federalregister
36741
Tuesday
July
7,
1998
Part
II
Environmental
Protection
Agency
40
CFR
Part
131
Water
Quality
Standards
Regulation;
Proposed
Rule
36742
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
ENVIRONMENTAL
PROTECTION
AGENCY
40
CFR
Part
131
[
FRL
 
0W
 
6118
 
9]

RIN
 
2040
 
AC56
Water
Quality
Standards
Regulation
AGENCY:
Environmental
Protection
Agency.
ACTION:
Advance
notice
of
proposed
rulemaking.

SUMMARY:
EPA
is
today
publishing
this
advance
notice
of
proposed
rule
making
(
ANPRM)
seeking
comments
from
interested
parties
on
possible
revisions
to
the
Water
Quality
Standards
Regulation
at
40
CFR
Part
131.
This
ANPRM
is
intended
to
initiate
discussions
on
what
if
any
changes
are
needed
in
the
national
water
quality
standards
program
to
improve
the
effectiveness
of
water
quality
standards
in
restoring
and
maintaining
the
quality
of
the
Nation's
waters.
EPA
will
consider
all
comments
before
deciding
whether
to
propose
revisions
to
the
regulation.
EPA
is
particularly
interested
in
comments
on
certain
key
portions
of
the
current
Water
Quality
Standards
Regulation
(
the
regulation)
contained
in
40
CFR
Part
131,
which
establishes
requirements
for
adoption
of
water
quality
standards
pursuant
to
section
303
of
the
Clean
Water
Act
(
CWA
or
the
Act).
This
ANPRM
identifies
specific
issues
on
which
EPA
solicits
comment.
In
addition
to
the
specific
issues
on
which
EPA
solicits
comments,
EPA
is
interested
in
comments
on
any
other
aspects
of
the
program.
EPA
requests
comments
with
the
objectives
of:
supporting
watershed
or
place­
based
environmental
water
quality
management,
ensuring
that
current
water
quality
criteria
and
water
quality
assessment
science
can
be
easily
incorporated
into
State
and
Tribal
water
quality
programs,
and
enhancing
effective
implementation
of
the
Act.
DATES:
Written
comments
must
be
submitted
by
midnight
January
4,
1999.
ADDRESSES:
Send
written
comments
to
W
 
98
 
01,
WQS­
ANPRM
Comment
Clerk,
Water
Docket,
MC
4101,
US
EPA,
401
M
Street,
S.
W.,
Washington,
D.
C.
20460.
Comments
may
also
be
submitted
electronically
to
OWDocket
epamail.
epa.
gov.
The
record
is
available
for
inspection
from
9:
00
to
4:
00
p.
m.,
Monday
through
Friday,
excluding
legal
holidays
at
the
Water
Docket,
East
Tower
Basement,
USEPA,
401
M
St.,
S.
W.,
Washington,
D.
C.
For
access
to
docket
materials,
please
call
(
202)
260
 
3027
to
schedule
an
appointment.

FOR
FURTHER
INFORMATION
CONTACT:
Rob
Wood
at
U.
S.
EPA
Standards
and
Applied
Science
Division
(
4305),
401
M
Street
SW,
Washington,
DC
20460
(
email
WOOD.
ROBERT@
EPA.
GOV)
(
telephone:
202
 
260
 
9536).

SUPPLEMENTARY
INFORMATION:
EPA
will
hold
a
series
of
full­
day
public
meetings
for
the
purpose
of
discussion
and
debate
on
the
issues
presented
in
this
notice.
EPA
plans
to
hold
the
public
meetings
during
the
180­
day
public
comment
period
on
this
notice.
Dates,
times
and
locations
of
public
meetings
will
be
announced
to
the
public.

A.
Potentially
Affected
Entities
This
ANPRM
by
itself
will
have
no
regulatory
impact
or
effect.
The
ANPRM
does
contain
EPA
interpretations
of
core
areas
of
the
regulation
as
well
as
EPA
thinking
about
how
the
regulation
may
need
to
be
changed.
As
discussed
in
more
detail
below,
this
ANPRM
marks
the
beginning
of
a
national
dialogue
on
possible
changes
to
the
water
quality
standards
regulation
and
program.
If
changes
to
the
regulation
are
proposed
and
ultimately
made
final,
to
the
extent
such
changes
would
require
and/
or
authorize
changes
to
State
and
Tribal
water
quality
standards,
States
and
authorized
Tribes
would
be
affected.
If
changes
to
State
and
Tribal
water
quality
standards
result
from
any
final
rule
that
EPA
may
promulgate
in
the
future,
entities
subject
to
compliance
with
State
or
Tribal
water
quality
standards
would
also
potentially
be
affected.
For
example,
States
and
Tribes
authorized
to
implement
the
National
Pollutant
Discharge
Elimination
System
(
NPDES)
Permit
Program
would
need
to
ensure
that
permits
they
issue
include
any
limitations
on
discharges
necessary
to
comply
with
any
water
quality
standards
established
as
a
result
of
any
subsequent
final
rulemaking.
Therefore,
entities
discharging
pollutants
to
waters
of
the
United
States
under
NPDES
could
be
affected
by
subsequent
proposed
and
final
rulemaking.
Categories
and
entities
that
may
ultimately
be
affected
include:

Category
Examples
of
potentially
affected
entities
State,
Tribes
and
Jurisdictional
Governments
.........................................
States,
Tribes
authorized
to
administer
water
quality
standards,
and
jurisdictional
governments.
Industry
.....................................................................................................
Industrial
dischargers
of
pollutants
to
waters
of
the
U.
S.
Municipalities
............................................................................................
Publicly­
owned
treatment
works
discharging
pollutants
to
waters
of
the
U.
S.

This
table
is
not
intended
to
be
exhaustive,
but
rather
provides
a
guide
for
readers
regarding
entities
that
could
be
affected
by
any
subsequent
final
rulemaking.
If
you
have
questions
regarding
the
applicability
of
this
action
to
a
particular
entity,
consult
the
person
listed
in
the
preceding
FOR
FURTHER
INFORMATION
CONTACT
section.

B.
Water
Docket
Information
The
record
for
this
notice
has
been
established
under
docket
number
W
 
98
 
01
and
includes
supporting
documentation.
When
submitting
written
comments
to
the
Water
Docket,
(
see
ADDRESSES
section
above)
please
reference
docket
number
[
W
 
98
 
01]
and
submit
an
original
and
three
copies
of
your
comments
and
enclosures
(
including
references).
To
ensure
that
EPA
can
read,
understand
and
therefore
properly
respond
to
comments,
the
Agency
would
prefer
that
commenters
cite
the
specific
question(
s)
in
the
notice
to
which
each
comment
refers.
The
questions
presented
in
this
notice
for
public
comment
are
organized
by
subsection
and
numbered.
Each
question
has
a
unique
number
(
for
example
III.
B.
3.
a.,
question
1)
for
this
purpose.
Comments
must
be
received
or
postmarked
by
midnight
January
4,
1999.
Commenters
who
want
EPA
to
acknowledge
receipt
of
their
comments
should
enclose
a
self­
addressed,
stamped
envelope.
No
facsimiles
(
faxes)
will
be
accepted.
Electronic
comments
are
encouraged
and
may
be
submitted
to
the
Water
Docket
(
see
ADDRESSES
section
above).
Electronic
comments
must
be
submitted
as
an
ASCII
file
or
a
WordPerfect
file
avoiding
the
use
of
special
characters
and
any
form
of
encryption.
Electronic
comments
must
be
identified
by
the
docket
number,
[
W
 
98
 
01],
and
be
received
by
midnight
of
January
4,
1999.
Comments
and
data
will
also
be
accepted
on
disks
in
WP5.1
format
or
36743
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
ASCII
file
format.
No
confidential
business
information
(
CBI)
should
be
sent
via
e­
mail.
The
remainder
of
this
Supplementary
Information
section
is
organized
as
follows:

I.
Purpose
and
Objectives
of
This
ANPRM
A.
General
Purpose
and
Vision
B.
Objectives
II.
Introduction
to
Water
Quality
Standards
A.
Statutory
History
B.
Regulatory
History
C.
Water
Quality
Guidance
for
the
Great
Lakes
System
III.
Program
Areas
for
Public
Comment
A.
Introduction
B.
Uses
1.
Background
2.
Refined
Designated
Uses
3.
Existing
Uses
a.
Protection
of
Existing
Uses
4.
Use
Attainability
a.
Attainability
of
Uses
b.
Removal
of
Designated
Uses
c.
Use
Attainability
Analysis
d.
Alternatives
to
``
Downgrade''
of
the
Designated
Use
i.
Variances
ii.
Temporary
Standards
iii.
Ambient­
based
Criteria
C.
Criteria
1.
Background
2.
Ambient
Water
Quality
Criteria
to
Protect
Aquatic
Life
3.
Site­
Specific
Criteria
4.
Narrative
Water
Quality
Criteria
5.
State
or
Tribe
Derived
Criteria
6.
Water
Quality
Criteria
for
Priority
Pollutants
7.
Criteria
for
Non­
Priority
Pollutants
with
Toxic
Effects
8.
Criteria
Where
Data
or
Guidance
is
Limited
9.
Toxicity
Criteria
10.
Sediment
Quality
Criteria
11.
Biological
Criteria
12.
Wildlife
Criteria
13.
Physical
Criteria
14.
Human
Health
a.
Risk
Levels
b.
Fish
Consumption
Assumptions
c.
Maximum
Contaminant
Levels
15.
Microbiological
Criteria
16.
Nutrient
Criteria
D.
Antidegradation
1.
Background
2.
General
Description
of
Antidegradation
3.
40
CFR
131.12
(
a)(
1)
``
tier
1''
a.
Tier
1
Implementation
4.
40
CFR
131.12
(
a)(
2)
``
tier
2''
a.
Identification
of
``
High
Quality''
Waters
b.
Tier
2
Implementation
i.
Triggers
for
tier
2
Review
ii.
``
Necessary''
Lowering
of
Water
Quality
iii.
Identification
of
``
Important''
Social
or
Economic
Activities
iv.
Tier
2
and
Identification
of
Waters
under
CWA
Section
303(
d)
v.
Achieving
all
cost­
effective
and
reasonable
best
management
practices
for
nonpoint
sources
5.
40
CFR
131.12
(
a)(
3)
``
tier
3''
a.
Designating
ONRWs
i.
Relationship
of
tier
3
to
the
Wild
and
Scenic
Rivers
Act
b.
Tier
3
Implementation
c.
Tier
21 
2
6.
40
CFR
131.12
(
a)(
4)
``
Thermal
Discharges''
E.
Mixing
Zones
1.
Background
2.
EPA
Policy
and
Guidance
on
Mixing
Zones
3.
State
and
Tribal
Mixing
Zone
Policies
4.
Mixing
Zone
Requirements
5.
Mixing
Analyses
6.
Narrative
Criteria
for
Mixing
Zones
7.
Mixing
Zones
for
Bioaccumulative
Pollutants
8.
Stream
Design
Flow
Policies
F.
Wetlands
as
Waters
of
the
United
States
G.
Independent
Application
Policy
1.
Introduction
a.
Biological
Assessments
b.
Toxicological
Assessments
c.
Chemical
Assessments
2.
Independent
Application
and
Water
Quality
Assessments
a.
Independent
Application
b.
Alternatives
to
Independent
Application
3.
Independent
Application
and
NPDES
Permitting
a.
Independent
Application
b.
Alternatives
to
Independent
Application
IV.
Summary
and
Potential
Program
and
Regulation
Changes
V.
Regulatory
Assessment
Requirements
A.
Executive
Order
(
E.
O.)
12866,
Regulatory
Planning
and
Review
B.
The
Regulatory
Flexibility
Act
(
RFA)
as
Amended
by
the
Small
Business
Regulatory
Enforcement
Fairness
Act
(
SBREFA)
of
1996
C.
Paperwork
Reduction
Act
I.
Purpose
and
Objectives
of
This
ANPRM
A.
General
Purpose
and
Vision
On
February
14,
1998,
the
visionary
``
Clean
Water
Action
Plan''
was
announced
by
the
Administrator
of
EPA
and
the
Secretary
of
Agriculture.
The
``
Clean
Water
Action
Plan''
is
a
blueprint
for
restoring
and
protecting
the
Nation's
precious
water
resources.
A
key
element
of
the
plan
is
advancement
of
the
watershed
approach
to
water
quality
protection.
EPA's
belief
is
that
refining
designated
uses
and
implementing
better
more
integrated
water
quality
criteria
to
protect
the
refined
uses,
two
important
themes
of
this
ANPRM,
are
essential
steps
in
carrying
out
the
blueprint
presented.
Revision
of
the
water
quality
standards
regulation
can
be
an
essential
component
in
implementing
the
vision
of
the
``
Clean
Water
Action
Plan.''
States,
Tribes
and
EPA
have
developed
functional
water
quality
standards
programs
under
the
current
regulation
and
these
programs
have
provided
the
basis
for
significant
water
quality
improvement
in
the
United
States.
Simply
put,
the
current
regulation
is
not
broken.
Rather,
with
the
renewed
interest
in
watershed
management
combined
with
improved
methods
for
water
quality
assessment,
a
comprehensive
evaluation
for
the
purpose
of
strengthening
the
regulation
is
appropriate
at
this
time.
EPA
and
the
public
need
to
examine
whether
changes
in
the
regulation
could
enhance
water
quality
management
on
a
watershed
basis
and
focus
resources
on
areas
of
greatest
concern.
A
review
of
the
regulation
will
also
complement
similar
outreach
discussions
EPA
is
currently
undertaking
for
the
purposes
of
reviewing
the
water
quality
planning
and
management
and
total
maximum
daily
load
(
TMDL)
programs
as
well
as
aspects
of
the
NPDES
program.
EPA
is
committed
to
ensuring
that
these
programs,
combined,
form
an
even
stronger
integrated
basis
for
water
quality
planning,
priority
setting
and
implementation
on
a
watershed
basis.
In
recent
years
there
has
been
a
rising
level
of
scrutiny
placed
on
water
quality
standards
and
the
State,
Tribal
and
EPA
decisions
based
on
water
quality
standards.
The
increased
scrutiny
comes
from
virtually
all
parties
affected
by
water
quality­
based
decisions
and
is
evidenced
by
the
growing
tide
of
challenges
to
State
standards,
EPA
policies
and
guidance,
and
individual
water
quality­
based
decisions.
Remaining
water
quality
problems
in
the
U.
S.
are
often
difficult
to
assess,
define
and
solve.
Once
agreed
upon,
the
solutions
will
be
less
conventional
than
we
are
used
to
and
may
result
in
different
regulatory
approaches.
Examples
of
such
problems
include
aquatic
and
riparian
habitat
destruction
from
municipal
and
agricultural
run­
off
and
fish
tissue
contamination
from
chemicals
with
many
and
diverse
sources.
EPA
believes
that
this
scrutiny
will
continue
and
that
an
evaluation
of
the
water
quality
standards
program
and
its
regulatory
and
policy
underpinnings
to
identify
where
these
program
underpinnings
may
need
to
be
strengthened,
clarified
or
revised
is
imperative.
Our
task
under
the
Clean
Water
Act
is
to
ensure
adequate
water
quality
even
where
it
is
difficult
to
do
so.
To
accomplish
this
task,
EPA
envisions
a
national
water
quality
standards
program
in
which:
the
best
possible
information
on
whether
designated
uses
are
being
attained
and
how
to
attain
and
maintain
them
is
available
and
used;
water
quality
criteria
are
selected
from
a
wide­
ranging
menu
of
scientifically
sound
criteria
that
can
be
tailored
to
each
watershed;
national
norms
of
consistency
and
flexibility
in
State
and
Tribal
water
quality
standards
are
clear;
and
innovative,
cost­
effective
approaches
are
36744
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
encouraged.
To
realize
this
vision,
EPA
believes
that
a
structured
national
debate
is
needed
to
identify
a
focused
set
of
issues
that
may
ultimately
lead
to
changes
to
the
water
quality
standards
regulation
and
policy.
The
ANPRM
process
allows
EPA
to
begin
this
work
by
consulting
with
all
interested
parties
to
find
out
what
changes,
if
any,
are
necessary
and
desirable,
to
make
the
water
quality
standards
regulation
more
responsive
to
current
needs
and
to
identify
opportunities
for
further
clarifications
of
policy
and
guidance
by
EPA.
In
the
fourteen
years
since
EPA
last
revised
the
water
quality
standards
regulation,
interested
parties
have
gained
considerable
experience
in
developing
and
implementing
water
quality
standards.
This
experience
will
provide
valuable
information
for
review
of
these
regulations.
The
most
significant
shift
in
water
quality
management
programs
in
recent
years
has
been
the
increased
emphasis
on
the
use
of
watershed
based
programs.
It
is
increasingly
apparent
that
EPA,
States,
Tribes,
municipalities
and
the
public
share
a
common
view
that
water
quality
programs,
including
water
quality
standards,
can
be
better
tailored
to
the
characteristics,
problems,
risks
and
implementation
tools
available
in
individual
watersheds
or
basins
with
meaningful
involvement
of
the
local
communities.
The
water
quality
standards
regulation
should
ensure
that
States
and
Tribes
have
the
flexibility
to
define
the
water
quality
standards
and
hence
the
environmental
objectives
of
a
water
body
according
to
the
characteristics
of
the
ecosystem
and
the
needs
of
the
water's
users
within
the
bounds
established
under
the
CWA.
The
regulation
must
allow
the
States
and
Tribes
to
tailor
water
body
use
designations
and
criteria
to
protect
these
uses
within
individual
basins
or
watersheds
based
on
the
needs
in
the
basin.
The
present
use
of
broad,
jurisdiction­
wide
use
classifications
and
lists
of
associated
chemical
criteria
may
be
at
once
too
general
and
too
narrow
for
some
waters,
lacking
the
refinement
necessary
to
tailor
water
quality
management
actions
to
specific
watersheds.
This
general
approach
reflects
the
historical
lack
of
information
on
specific
basins
or
water
bodies
and
the
need
to
ensure
that
all
waters
receive
adequate
protection.
Additionally,
it
should
be
made
clear
how
much
flexibility
States
and
Tribes
have
to
adjust
use
designations
as
information
improves
about
whether
a
designated
use
or
a
higher
use
can
be
attained
and
to
reflect
natural
and
human
caused
changes
in
water
quality
that
may
have
occurred.
The
challenge
for
EPA,
States
and
Tribes
is
to
identify
and
use
opportunities
to
refine
use
designations
for
waters
where
it
makes
sense
and
better
match
the
water
quality
criteria
to
the
refined
use,
thus
making
water
quality
standards
more
flexible.
In
addition,
to
more
effectively
implement
the
standards,
the
criteria
that
are
used
need
to
better
integrate
multiple
stressors
and
their
cumulative
impacts
in
order
to
more
effectively
protect
designated
uses.
Significant
scientific
advancements
in
recent
years
have
added
to
the
ability
to
assess
environmental
impacts
and
risks
related
to
changes
in
water
quality.
As
they
are
further
developed,
new
and
emerging
sophisticated
and
integrated
analytical
tools
such
as
bioassessment,
criteria
for
bioaccumulative
chemicals,
sediment
quality
criteria
and
toxicity
assessments
will
increasingly
allow
States,
Tribes,
EPA
and
the
public
to
characterize
better
the
ecological
condition
of
water
resources.
At
present,
this
improving
capability,
used
in
a
tailored
watershed
planning
and
management
framework,
can
enhance
the
ability
of
States
and
Tribes
to
characterize
and
protect
locally
agreed
upon
goals
for
maintaining
and
protecting
the
chemical,
physical
and
biological
integrity
of
individual
basins.
In
the
long
term,
chemical,
physical
and
biological
assessment
methods
will
continue
to
improve.
As
they
do,
the
water
quality
standards
program
should
be
designed
to
accommodate
effectively
the
new
science.
In
the
meantime,
progress
should
not
be
stalled
by
incomplete
knowledge.
With
the
new
science
and
assessment
methodologies,
however,
come
new
challenges
for
States
and
Tribes
to
identify
the
resources
necessary
to
make
use
of
these
advances.
One
of
the
main
themes
of
this
ANPRM
is
the
need
for
better
data,
and
new
types
of
data,
in
order
to
support
a
more
refined
approach
to
water
quality
protection.
EPA
recognizes,
however,
that
efforts
to
obtain
such
data,
and
develop
the
analytical
capacity
to
integrate
it
into
existing
regulatory
programs,
could
encounter
significant
resource
constraints
in
some
States
and
Tribes.
EPA
is
well
aware
that
in
order
for
a
new,
data­
intensive,
watershed­
specific
approach
to
succeed,
it
must
be
workable
for
the
States
and
Tribes
that
will
have
to
implement
it.
EPA
welcomes
comments
regarding
concerns
over
resource
constraints
and
ideas
for
how
to
address
them.
The
water
quality
standards
program
must
protect
the
nation's
waters
as
envisioned
in
the
CWA.
It
must
establish
requirements
that
are
necessary
to
attain
and
maintain
healthy,
sustainable
ecosystems.
It
must
be
flexible
enough
for
States
and
Tribes
to
ensure
that
standards
are
protecting
water
quality
in
a
way
that
makes
sense.
EPA
seeks
to
avoid
a
program
that
results
in
costly
requirements
that
have
little
or
no
environmental
benefit.
Thus
EPA
intends
to
use
its
experience
and
that
of
the
States,
Tribes,
municipalities,
the
regulated
community,
environmental
groups
and
the
general
public
in
implementing
and
utilizing
water
quality
standards
over
the
last
fourteen
years,
to
evaluate
the
regulation
and
determine
if
changes
are
needed
to
allow
greater
State,
Tribal
and
local
flexibility
to
develop
innovative,
cost­
effective
ways
to
protect
water
quality.
EPA
may
determine
through
the
ANPRM
process
that
the
concepts
described
above
can
be
better
integrated
into
water
quality
management
decision
making
through
development
of
new
or
revised
policies
and
guidance
rather
than
revisions
to
the
regulation.
Because
of
this
possibility,
EPA
is
reserving
its
decision
whether
to
propose
and
finalize
revisions
to
the
regulation.
At
minimum,
EPA
believes
that
any
revisions
to
the
water
quality
standards
regulation
should
result
in
a
regulation
that
can
be
used
to
render
protective,
tailored,
site­
specific
water
qualitybased
decisions
that
bear
reasonable
compliance
costs
for
the
regulated
community,
as
well
as
reasonable
implementation
costs
for
States,
Tribes
and
EPA.
At
the
same
time,
the
regulation
should
allow
sufficient
flexibility
to
States
and
Tribes,
if
they
choose,
to
implement
water
quality
standards
programs
in
a
manner
that
is
no
more
burdensome
than
under
the
existing
regulation.

B.
Objectives
In
publishing
this
ANPRM,
EPA
is
beginning
a
review
of
the
regulation
in
a
public
forum
in
an
attempt
to
identify
possible
amendments
to
the
regulation,
and
new
guidance
or
policy
that
may
be
needed
to
address
three
distinct
objectives.
They
are:
(
1)
to
eliminate
any
barriers
and
develop
incentives
to
enhance
State
and
Tribal
implementation
of
watershed­
based
water
quality
planning
and
management;
(
2)
to
enhance
State
and
Tribal
capability
to
incorporate
current
criteria
and
water
quality
assessment
science
into
their
water
quality
standards
programs,
and;
(
3)
to
improve
the
regulation
so
that
it
may
be
implemented
more
efficiently
and
effectively
(
including
cost­
effectively).
Meeting
these
three
objectives,
EPA
believes,
will
facilitate
further
water
36745
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
quality
improvements
locally
and
nationally.
EPA
urges
commenters
to
keep
all
three
main
objectives
in
mind
when
reviewing,
analyzing
and
commenting
on
this
ANPRM.

II.
Introduction
to
Water
Quality
Standards
A.
Statutory
History
The
first
comprehensive
legislation
for
water
pollution
control
was
the
Water
Pollution
Control
Act
of
1948
(
Pub.
L.
845,
80th
Congress).
This
law
adopted
principles
of
State­
Federal
cooperative
program
development,
limited
federal
enforcement
authority,
and
limited
federal
financial
assistance.
These
principles
were
continued
in
the
Federal
Water
Pollution
Control
Act
(
Pub.
L.
660,
84th
Congress)
in
1956
and
in
the
Water
Quality
Act
of
1965.
Under
the
1965
Act,
States
were
directed
to
develop
water
quality
standards
establishing
water
quality
goals
for
interstate
waters.
By
the
early
1970'
s,
all
the
States
had
adopted
such
water
quality
standards.
Since
then,
States
have
revised
their
standards
to
reflect
new
scientific
information,
the
impact
on
water
quality
of
economic
development
and
the
results
of
water
quality
controls.
Due
to
enforcement
complexities
and
other
problems,
an
approach
based
solely
on
water
quality
standards
was
deemed
too
weak
to
make
a
difference.
The
purely
water
quality­
based
approach
prior
to
1972
lacked
enforceable
Federal
mandates
and
standards,
and
a
strong
impetus
to
implement
plans
for
water
quality
improvement.
The
result
was
an
incomplete
program
that
in
Congress'
view
needed
strengthening.
In
the
Federal
Water
Pollution
Control
Act
Amendments
of
1972
(
Pub.
L.
92
 
500,
Clean
Water
Act
or
CWA),
Congress
established
the
National
Pollutant
Discharge
Elimination
System
(
NPDES)
whereby
each
point
source
discharger
to
waters
of
the
U.
S.
is
required
to
obtain
a
discharge
permit.
The
1972
Amendments
required
EPA
to
establish
technology­
based
effluent
limitations
that
are
to
be
incorporated
into
NPDES
permits.
In
addition,
the
amendments
extended
the
water
quality
standards
program
to
intrastate
waters
and
required
NPDES
permits
to
be
consistent
with
applicable
State
water
quality
standards.
Thus,
the
CWA
established
complementary
technologybased
and
water
quality­
based
approaches
to
water
pollution
control.
Now,
after
nearly
25
years
of
investment
in
technology­
based
controls
and
some
$
70
billion
in
sewage
treatment
plant
construction,
attention
is
turning
back
to
water
quality
standards
as
a
mechanism
to
make
improvements
in
water
quality
beyond
those
that
have
been
achieved
through
technologybased
controls.
Water
quality
standards
serve
as
the
foundation
for
the
water­
quality
based
approach
to
pollution
control
and
are
a
fundamental
component
of
watershed
management.
Water
quality
standards
are
State
or
Tribal
law
or
regulation
that:
define
the
water
quality
goals
of
a
water
body,
or
segment
thereof,
by
designating
the
use
or
uses
to
be
made
of
the
water;
set
criteria
necessary
to
protect
the
uses;
and
protect
water
quality
through
antidegradation
provisions.
Although
the
CWA
gives
EPA
an
important
role
in
determining
appropriate
minimum
levels
of
protection
and
providing
national
oversight,
it
also
gives
considerable
flexibility
and
discretion
to
States
and
Tribes
to
design
their
own
programs
and
establish
levels
of
protection
above
the
national
minimum.
States
and
Tribes
adopt
water
quality
standards
to
protect
public
health
or
welfare,
enhance
the
quality
of
water,
and
serve
the
purposes
of
the
Act.
``
Serve
the
purposes
of
the
Act''
(
as
defined
in
Sections
101(
a),
101(
a)(
2),
and
303(
c)
of
the
Act)
means
that
water
quality
standards
should:
(
1)
include
provisions
for
restoring
and
maintaining
chemical,
physical,
and
biological
integrity
of
State
and
Tribal
waters,
(
2)
provide,
wherever
attainable,
water
quality
for
the
protection
and
propagation
of
fish,
shellfish,
and
wildlife
and
recreation
in
and
on
the
water
(``
fishable/
swimmable''),
and
(
3)
consider
the
use
and
value
of
State
and
Tribal
waters
for
public
water
supplies,
propagation
of
fish
and
wildlife,
recreation,
agricultural
and
industrial
purposes,
and
navigation.
See
40
CFR
131.2.
Section
303(
c)
of
the
CWA
establishes
the
basis
for
the
current
water
quality
standards
program.
Section
303(
c):
1.
Defines
water
quality
standards;
2.
Identifies
acceptable
beneficial
uses:
public
water
supply,
propagation
of
fish
and
wildlife,
recreational
purposes,
agricultural
and
industrial
water
supplies
and
navigation;
3.
Requires
that
State
and
Tribal
standards
protect
public
health
or
welfare,
enhance
the
quality
of
water
and
serve
the
purposes
of
the
Act;
4.
Requires
that
States
and
Tribes
review
their
standards
every
three
years;
5.
Establishes
the
process
for
EPA
review
of
State
and
Tribal
standards,
including
where
necessary
the
promulgation
of
a
superseding
Federal
rule
in
cases
where
a
State's
or
Tribe's
standards
are
not
consistent
with
applicable
requirements
of
the
CWA
or
in
situations
where
the
Administrator
determines
that
Federal
standards
are
necessary
to
meet
the
requirements
of
the
Act.
The
decade
of
the
1970'
s
saw
State
and
EPA
attention
focus
on
creating
the
infrastructure
necessary
to
support
the
NPDES
permit
program
and
development
of
technology­
based
effluent
limitations.
While
the
water
quality
standards
program
continued,
it
was
a
low
priority
in
the
overall
CWA
program.
In
the
early
1980'
s,
it
began
to
be
recognized
that
greater
attention
to
the
water
quality­
based
approach
to
pollution
control
would
be
needed
to
effectively
protect
and
enhance
all
of
the
nation's
waters.
The
first
statutory
evidence
of
this
was
the
enactment
of
a
CWA
requirement
that
after
December
29,
1984,
no
construction
grant
could
be
awarded
for
projects
that
discharged
into
stream
segments
which
had
not,
at
least
once
since
December
1981,
had
their
water
quality
standards
reviewed
and
revised
or
new
standards
adopted
as
appropriate
under
Section
303(
c).
(
Public
Law
97
 
117,
Section
24,
``
Revised
Water
Quality
Standards.'')
The
efforts
by
the
States
to
comply
with
this
one­
time
requirement
essentially
made
the
States'
water
quality
standards
current
as
of
that
date
for
segments
with
publicly­
owned
treatment
works
(
POTWs)
discharging
into
them.
Additional
impetus
to
the
water
quality
standards
program
occurred
on
February
4,
1987,
when
Congress
enacted
the
Water
Quality
Act
of
1987
(
Pub.
L.
100
 
4).
Congressional
impatience
with
the
lack
of
progress
in
State
adoption
of
standards
for
toxics
(
which
had
been
a
national
program
priority
since
the
early
1980'
s)
resulted
in
the
1987
adoption
of
new
water
quality
standard
provisions
in
the
Water
Quality
Act
amendments.
These
amendments
reflected
Congress'
conclusion
that
toxic
pollutants
in
water
are
one
of
the
most
pressing
water
pollution
problems.
One
concern
Congress
had
was
that
States
were
relying,
for
the
most
part,
on
narrative
criteria
to
control
toxics
(
e.
g.,
``
no
toxics
in
toxic
amounts''),
which
made
development
of
effluent
limitations
in
permits
difficult.
To
remedy
this,
Congress
adopted
section
303(
c)(
2)(
B),
which
essentially
required
development
of
numeric
criteria
for
those
water
body
segments
where
toxic
pollutants
were
likely
to
adversely
affect
designated
uses.
The
1987
Amendments
gave
new
teeth
to
the
control
of
toxic
pollutants.
As
Senator
Mitchell
put
it,
Section
303(
c)(
2)(
B)
requires
``
States
to
identify
waters
that
do
not
meet
water
quality
36746
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
standards
due
to
the
discharge
of
toxic
substances,
to
adopt
numerical
criteria
for
the
pollutants
in
such
waters,
and
to
establish
effluent
limitations
for
individual
discharges
to
such
water
bodies.''
(
From
Senator
Mitchell,
133
Cong.
Rec.
S733.)
To
assist
States
in
complying
with
Section
303(
c)(
2)(
B),
EPA
issued
program
guidance
in
December
1988
and
instituted
an
expanded
program
of
training
and
technical
assistance.
Section
518
was
another
major
addition
in
the
1987
Amendments
to
the
Act.
This
section
extended
participation
in
the
water
quality
standards
and
401
certification
programs
to
certain
Indian
Tribes.
The
Act
directed
EPA
to
establish
procedures
by
which
a
Tribe
could
``
qualify
for
treatment
as
a
State,''
at
its
option,
for
purposes
of
administering
the
standards
and
401
certification
programs.
The
Act
also
required
EPA
to
create
a
mechanism
to
resolve
disputes
that
might
develop
when
unreasonable
consequences
arise
from
a
Tribe
and
a
State
or
another
Tribe
adopting
different
water
quality
standards
on
common
bodies
of
water.
Furthermore,
with
the
1987
Amendments,
the
Act
explicitly
recognized
EPA's
antidegradation
policy
for
the
first
time.
The
intent
of
the
antidegradation
policy
in
EPA's
regulation
was
and
is
to
protect
existing
uses
and
the
level
of
water
quality
necessary
to
protect
existing
uses
and
to
provide
a
means
for
assessing
activities
that
may
impact
high
quality
waters
and
ruling
on
whether
such
projects
could
proceed.
Section
303(
d)(
4)
of
the
Act
requires
that
water
quality
standards
in
those
waters
that
meet
or
exceed
levels
necessary
to
support
designated
uses
``
may
be
revised
only
if
such
revision
is
subject
to
and
consistent
with
the
antidegradation
policy
established
under
this
section.''

B.
Regulatory
History
In
the
late
1960'
s
and
early
1970'
s
the
water
quality
standards
program
was
initiated
and
administered
based
on
minimal
guidance
and
Federal
policies
 
many
of
which
are
still
reflected
in
the
water
quality
standards
program
today.
EPA
first
promulgated
a
water
quality
standards
regulation
in
1975
(
40
CFR
130.17,
40
FR
55334,
November
28,
1975)
as
part
of
EPA's
water
quality
management
regulations
mandated
under
Section
303(
e)
of
the
Act.
As
discussed
earlier,
the
standards
program
had
a
relatively
low
priority
during
this
time.
This
was
reflected
in
the
minimal
requirements
of
the
first
Water
Quality
Standards
Regulation.
Few
requirements
on
designating
water
uses
and
procedures
were
included.
The
Regulation
was
general,
requiring
``
appropriate''
water
quality
criteria
necessary
to
support
designated
uses
and
incorporating
the
antidegradation
policy.
Toxic
pollutants
or
any
other
specific
criteria
were
not
mentioned.
Some
States
developed
detailed
water
quality
standards
regulations
while
others
adopted
only
general
provisions
which
proved
to
be
of
limited
use
in
the
management
of
increasingly
complex
water
quality
problems
and
created
disparities
in
requirements
on
regulated
entities.
The
few
water
quality
criteria
that
were
adopted
addressed
a
limited
number
of
pollutants
and
primarily
described
fundamental
water
quality
conditions
(
e.
g.,
pH,
temperature,
dissolved
oxygen
and
suspended
solids)
or
dealt
with
conventional
pollutants.
In
the
late
1970s,
EPA
determined
that
existing
State
water
quality
standards
needed
to
be
better
developed.
EPA
moved
to
strengthen
the
water
quality
program
to
complement
the
technology
based
controls.
EPA
amended
the
Water
Quality
Standards
Regulation
to
explicitly
address
toxic
criteria
requirements
in
State
standards
and
other
legal
and
programmatic
issues.
November
8,
1983
(
54
FR
51400).
This
regulation
is
more
comprehensive
than
its
predecessor
and
includes
more
specific
regulatory
and
procedural
requirements.
The
1983
regulation
created
the
concept
of
use
attainability
analysis,
added
detail
on
the
adoption
of
numeric
criteria
including
authorization
for
site­
specific
criteria,
and
listed
specific
procedural
requirements
and
definitions
not
included
in
the
original
1975
regulation.
The
regulation
specified
the
roles
of
the
States
and
EPA
and
the
administrative
requirements
for
States
in
adopting
and
submitting
their
standards
to
EPA
for
review.
It
also
delineated
the
EPA
requirements
for
review
of
State
standards
and
promulgation
of
federal
standards.
The
1983
regulation
provided
States
(
and
subsequently
in
1991)
Tribes
with
the
option
of
refining
their
use
designation
process
by
allowing
them
to
establish
subcategories
of
uses,
such
as
cold
water
and
warm
water
aquatic
life
designations.
The
1983
regulation
also
clarified
that
States
(
and
subsequently
Tribes)
may
adopt
discretionary
policies
affecting
the
implementation
of
standards,
such
as
mixing
zones,
low
flows,
and
variances.
In
support
of
the
1983
Regulation,
EPA
simultaneously
issued
program
guidance
entitled
Water
Quality
Standards
Handbook
(
December,
1983).
The
Handbook
provided
guidance
on
the
interpretation
and
implementation
of
the
Water
Quality
Standards
Regulation.
This
document
also
contained
information
on
scientific
and
technical
analyses
that
are
used
in
making
decisions
that
would
impact
water
quality
standards.
EPA
also
developed
the
Technical
Support
Document
for
Water
Quality­
Based
Toxics
Control
(
EPA
44/
4
 
85
 
032,
September,
1985)
(
TSD)
which
provided
additional
guidance
for
implementing
State
water
quality
standards.
In
1991,
EPA
revised
and
expanded
the
TSD.
(
EPA
505/
2
 
90
 
001,
March
1991).
In
1994,
EPA
issued
the
Water
Quality
Standards
Handbook:
Second
Edition
(
EPA
 
823
 
B
 
94
 
006,
August
1994).
To
accelerate
compliance
with
CWA
section
303(
c)(
2)(
B)
(
created
by
the
1987
Water
Quality
Act),
EPA
started
action
in
1990
to
promulgate
numeric
water
quality
criteria
for
those
States
that
had
not
adopted
sufficient
water
quality
standards
for
toxic
pollutants.
The
intent
of
the
rulemaking,
known
as
the
National
Toxics
Rule,
was
to
strengthen
State
water
quality
management
programs
by
increasing
the
level
of
protection
afforded
to
aquatic
life
and
human
health
through
the
adoption
of
all
available
criteria
for
toxic
pollutants
listed
under
307(
a)
of
the
CWA
(
priority
pollutants)
present
or
likely
to
be
present
in
State
waters.
This
action
culminated
on
December
22,
1992,
with
EPA
promulgating
Federal
water
quality
criteria
for
priority
toxic
pollutants
for
14
States
and
Territories
(
see
57
FR
60848).
Subsequent
to
the
promulgation
of
criteria
under
the
National
Toxics
Rule,
EPA
altered
its
national
policy
on
the
expression
of
aquatic
life
criteria
for
metals.
On
May
4,
1995
at
60
FR
22228,
EPA
issued
a
stay
of
several
metals
criteria
(
expressed
as
total
recoverable
metal)
previously
promulgated
under
the
National
Toxics
Rule
for
the
protection
of
aquatic
life.
EPA
simultaneously
issued
an
interim
final
rule
that
changed
these
metal
criteria
promulgated
under
the
National
Toxics
Rule
from
the
total
recoverable
form
to
the
dissolved
form.
The
Water
Quality
Standards
Regulation
was
amended
in
1991
to
implement
Section
518
of
the
Act
to
expand
the
standards
program
to
include
Indian
Tribes
(
56
FR
64893,
December
12,
1991).
EPA
added
40
CFR
131.7
to
describe
the
requirements
of
the
issue
dispute
resolution
mechanism
(
to
resolve
unreasonable
consequences
that
may
arise
between
a
Tribe
and
a
State
or
another
Tribe
when
differing
water
quality
standards
have
been
adopted
for
a
common
body
of
water)
and
40
CFR
131.8
to
establish
the
36747
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
procedures
by
which
a
Tribe
applies
for
authorization
to
assume
the
responsibilities
of
the
water
quality
standards
and
section
401
certification
programs.
Fourteen
years
since
its
last
major
revision,
the
water
quality
standards
regulation
is
undergoing
review
and
potential
revision
in
light
of
experiences
gained
in
its
implementation
by
States,
Tribes,
EPA
and
the
public.
The
review
is
intended
to
reflect
the
changing
nature
of
the
program
and
to
identify
specific
changes
that
will
strengthen
water
quality
protection
and
restoration,
facilitate
watershed
management
initiatives,
and
incorporate
evolving
water
quality
criteria
and
assessment
science
into
water
quality
standards
programs.
Based
on
the
review
and
the
comments
expected
on
the
ANPRM,
EPA
may
decide
to
revise
parts
of
the
regulation
and/
or
change
some
of
its
existing
policies
and
guidance
for
the
water
quality
standards
program.
Water
quality
standards
are
essential
to
a
wide
range
of
surface
water
activities,
including:
(
1)
setting
and
revising
water
quality
goals
for
watersheds
and/
or
individual
water
bodies,
(
2)
monitoring
water
quality
to
provide
information
upon
which
water
quality­
based
decisions
will
be
made,
(
3)
calculating
total
maximum
daily
loads
(
TMDLs),
waste
load
allocations
(
WLAs)
for
point
sources
of
pollution,
and
load
allocations
(
LAs)
for
natural
background
and
nonpoint
sources
of
pollution,
(
4)
developing
water
quality
management
plans
which
prescribe
the
regulatory,
construction,
and
management
activities
necessary
to
meet
the
water
body
goals,
(
5)
calculating
NPDES
water
quality­
based
effluent
limitations
for
point
sources,
in
the
absence
of
TMDLs,
WLAs,
LAs,
and/
or
water
quality
management
plans,
(
6)
preparing
various
reports
and
lists
that
document
the
condition
of
the
State's
or
Tribe's
water
quality,
and
(
7)
developing,
revising,
and
implementing
an
effective
section
319
management
program
which
outlines
the
State's
or
Tribe's
control
strategy
for
nonpoint
sources
of
pollution.

Note:
The
term
``
State''
as
used
in
this
Notice
refers
to
the
fifty
States,
all
Territories
of
the
United
States,
and
the
District
of
Columbia.
The
term
``
Tribe''
or
``
Tribal''
as
used
in
this
Notice
generally
refers
to
all
Indian
Tribes
authorized
to
administer
the
water
quality
standards.
On
occasion,
the
term
``
Tribe''
or
``
Tribal''
refers
to
Indian
Tribes
that
are
eligible
to
seek
authorization
to
administer
the
water
quality
standards,
but
have
not
yet
secured
such
authorization.
There
are
some
parts
of
the
law
and
regulation
where
``
State''
is
now
interpreted
to
mean
``
State
or
Tribe.''
C.
Water
Quality
Guidance
for
the
Great
Lakes
System
On
March
23,
1995,
EPA
published
in
the
Federal
Register
its
Water
Quality
Guidance
for
the
Great
Lakes
System
(
60
FR
15366,
March
23,
1995)
(
Great
Lakes
Guidance).
The
Guidance
consists
of
water
quality
criteria
for
29
pollutants
to
protect
aquatic
life,
wildlife,
and
human
health,
and
detailed
methodologies
to
develop
criteria
for
additional
pollutants;
implementation
procedures
to
develop
more
consistent,
enforceable
water
quality­
based
effluent
limits
in
discharge
permits,
as
well
as
TMDLs
of
pollutants
that
can
be
allowed
to
reach
the
Great
Lakes
and
their
tributaries
from
all
sources;
and
antidegradation
policies
and
procedures.
Section
118(
c)(
2)
of
the
Clean
Water
Act
(
CWA)
(
Pub.
L.
92
 
500
as
amended
by
the
Great
Lakes
Critical
Programs
Act
of
1990
(
CPA),
Pub.
L.
101
 
596,
November
16,
1990)
required
EPA
to
publish
proposed
and
final
water
quality
guidance
on
minimum
water
quality
standards,
antidegradation
policies,
and
implementation
procedures
for
the
Great
Lakes
System.
EPA
responded
to
these
requirements
by
initiating
a
rulemaking,
publishing
the
Proposed
Water
Quality
Guidance
for
the
Great
Lakes
System
(
proposed
Guidance)
in
the
Federal
Register
on
April
16,
1993
(
58
FR
20802).
EPA
also
published
four
subsequent
documents
in
the
Federal
Register
identifying
corrections
and
requesting
comments
on
additional
related
materials.
EPA
received
over
26,500
pages
of
comments,
data,
and
information
from
over
6,000
commenters
in
response
to
these
documents
and
from
meetings
with
members
of
the
public.
After
reviewing
and
analyzing
the
information
in
the
proposal
and
these
comments,
EPA
developed
and
published
the
Great
Lakes
Guidance,
codified
at
40
CFR
Part
132.
Part
132
contains
six
appendixes
of
detailed
methodologies,
policies,
and
procedures.
Detailed
discussion
of
the
final
Guidance
is
provided
in
``
Final
Water
Quality
Guidance
for
the
Great
Lakes
System:
Supplementary
Information
Document''
(
SID),
(
EPA,
1995,
820
 
B
 
95
 
001)
and
in
additional
technical
and
supporting
documents
which
are
available
in
the
docket
for
the
rulemaking.
Copies
of
the
SID
and
other
supporting
documents
are
also
available
from
EPA
in
electronic
format,
or
in
printed
form
for
a
fee
upon
request.
Developing
the
Great
Lakes
Guidance
was
an
enormous
effort
based
on
extensive
public
comment
and
analysis
on
some
of
the
same
issues
that
are
addressed
in
this
ANPRM.
One
principal
difference
between
the
provisions
in
the
Great
Lakes
Guidance
and
the
regulation,
policy
and
guidance
that
is
the
subject
of
this
ANPRM
is
that
where
the
Great
Lakes
Guidance
addressed
programs
in
the
Great
Lakes
States
only,
this
ANPRM
addresses
the
national
water
quality
standards
regulation
and
program,
and
thus
the
programs
of
all
States
and
Tribes
with
water
quality
standards
authority.
Where
the
Great
Lakes
Guidance
addressed
an
issue
or
issue
area
that
is
also
addressed
in
the
ANPRM,
that
analysis
and
conclusion
may
or
may
not
be
relevant
to
the
discussion
of
the
national
program.
Where
it
is,
today's
ANPRM
identifies
the
specific
relevant
Great
Lakes
Guidance
provisions
in
the
specific
issue
discussions.
Many
of
the
provisions
in
the
Great
Lakes
Guidance
were
developed
to
address
the
unique
problems
in
the
Great
Lakes
Basin
that
stem
from
known
contamination
by
bioaccumulative
chemicals
and
the
long
retention
time
of
water
in
the
Lakes.
Commenters
should
keep
in
mind
that
the
Great
Lakes
provisions
were
derived
for
States
that
are
in
the
Great
Lakes
Basin
in
whole
or
part
and
should
consider
the
uniqueness
of
the
Great
Lakes
Basin
when
evaluating
Great
Lakes
Guidance
provisions
for
application
outside
of
the
Great
Lakes
Basin.

III.
Program
Areas
for
Public
Comment
A.
Introduction
Entering
its
33rd
year,
the
water
quality
standards
program
has
begun
to
evolve
from
one
with
a
narrow
focus
on
establishing
water
body
uses
and
adopting
chemical
criteria
for
basic
water
quality
characteristics
addressing
the
most
obvious
sources
of
pollution
to
a
more
comprehensive
program.
In
recent
years
the
scientific
community
has
developed
greater
knowledge
of
the
full
range
of
stressors
adversely
impacting
surface
waters.
EPA
believes
the
water
quality
standards
program
should
evolve
to
keep
pace
with
expanding
science
to
address
water
quality
problems
in
a
more
comprehensive
way,
accommodating
more
specific
and
sophisticated
water
use
classifications,
criteria
for
more
pollutants,
new
forms
of
criteria
and
companion
ecological
and
health
indicators,
and
closer
integration
with
other
programs.
At
the
same
time,
EPA
realizes
that
such
an
evolution
could
require
a
significant
increase
in
analytical
resources
from
States,
Tribes
and
the
regulated
community,
and
that
changes
to
the
existing
program
must
be
structured
in
a
way
that
is
workable.
36748
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
This
is
an
appropriate
time
to
begin
a
structured
national
debate
aimed
at
identifying
the
focused
changes
necessary
to
strengthen
the
underpinnings
of
water
quality
standards
and
implementation.
In
the
fourteen
years
since
the
regulation
was
last
revised,
there
have
been
numerous
scientific
developments,
statutory
changes,
court
decisions,
and
implementation
issues
affecting
the
water
quality
standards
program.
The
shift
in
program
focus
beyond
just
chemical
contamination
to
include
ecosystem
protection
and
watershed
approaches
necessitates
reexamining
basic
program
concepts.
In
addition,
there
is
an
opportunity
to
address
possible
barriers
to
effective
water
quality
improvements
where
it
is
determined
that
regulatory
changes
are
possible
under
existing
law.
In
recent
years,
EPA
has
heard
from
the
States
and
Tribes
as
well
as
the
environmental
and
regulated
communities
regarding
the
necessity
and
focus
of
a
revision
to
the
water
quality
standards
regulation.
As
indicated
by
the
wide
range
of
issues
and
options
presented
in
this
advance
notice,
views
of
the
different
stakeholder
groups
often
differ
considerably.
Many
stakeholders
believe
that
a
revised
regulation
is
needed
for
continued
improvements
in
water
quality
protection.
Others
believe
changes
are
needed
to
allow
more
flexible,
cost­
effective
approaches
by
States
and
Tribes.
Conversely,
many
stakeholders
have
said
that
the
regulation
is
sufficient
and
does
not
need
to
be
reviewed.
A
key
issue
presented
here
relates
to
the
degree
of
specificity
necessary
should
EPA
revise
the
regulation.
There
are
many
who
support
a
more
flexible
regulation
to
allow
States
and
Tribes
to
address
new
and
changing
circumstances.
Under
a
more
flexible
regulation,
States
and
Tribes
could
more
easily
tailor
their
programs
to
deal
with
pressing
water
quality
restoration
and
protection
needs
that
are
not
well
addressed
presently.
Others
support
a
regulation
with
more
specific
regulatory
requirements.
The
latter
would
promote
a
more
consistent
minimal
level
of
protection
in
State
and
Tribal
water
quality
standards,
provide
more
clarity
on
standards
issues,
and
serve
as
a
stronger
tool
in
encouraging
States
and
Tribes
to
take
appropriate
restoration
and
protection
actions.
EPA
urges
commenters
to
consider
the
appropriate
balance
between
flexibility,
national
consistency,
and
consistency
within
States
and
Tribes
when
commenting
on
any
of
the
ideas
presented
in
this
notice.
One
of
the
outcomes
of
this
ANPRM
and
follow­
on
actions
can
be
establishment
of
a
clearer
set
of
national
minimum
policies
and
implementation
procedures
on
which
EPA
will
reliably
and
predictably
base
its
approval
and
disapproval
decisions
on
State
and
Tribal
water
quality
standards
submittals.
EPA
remains
committed
to
making
consistent
decisions
from
State
to
State
and
Tribe
to
Tribe
and
State
to
Tribe
to
meet
our
obligation
to
ensure
an
appropriate
level
of
protection
nationally
and
that
the
goals
of
the
Act
are
achieved.
Clarifying
these
national
norms
will
serve
to
better
articulate
the
norms
of
protection
from
State
to
State
and
Tribe
to
Tribe
and
State
to
Tribe
and
also
to
clarify
national
norms
of
flexibility.
Defining
the
appropriate
level
of
consistency,
in
turn,
defines
the
appropriate
degree
level
of
flexibility.
In
addition,
establishing
norms
of
consistency
and
flexibility
should
help
to
resolve
State
or
Tribal
differences
with
EPA
on
water
quality
standards
early
in
the
process,
before
the
approval/
disapproval
stage.
While
the
following
discussion
describes
specific
areas
and
issues
for
public
review,
the
public
is
welcome
to
comment
on
any
aspect
of
the
water
quality
standards
program.
EPA
emphasizes,
however,
that
publication
of
this
Notice
does
not
commit
the
Agency
to
proceeding
with
a
regulatory
change.
EPA
has
not
decided
whether
it
will,
in
fact,
propose
regulatory
amendments,
and,
if
proposed,
how
extensive
that
effort
might
be.
This
decision
will
be
made
after
considering
the
comments
received
and
the
need
to
address
other
priority
activities
as
well
as
any
Congressional
and
Executive
Branch
directives.
A
potential
outcome
of
this
public
review
may
be
additional
guidance
and/
or
policies
rather
than
regulatory
changes.
EPA
has
not
determined
the
next
steps
it
will
take
after
evaluation
of
all
the
comments
received
on
this
ANPRM.
It
is
likely
that
any
follow­
on
proposed
rule
to
amend
40
CFR
131
would
focus
on
a
relatively
narrow
set
of
issues
and
that
many
other
issues
could
be
resolved
through
policy
and
guidance.
EPA
requests
that
commenters
identify
the
five
to
seven
issues
considered
highest
priority
for
possible
regulatory
amendments.
The
summary
section
at
the
end
of
this
notice
contains
a
brief
summary
of
the
potential
changes
to
the
water
quality
standards
regulation
that
are
discussed
and
considered
in
this
ANPRM.
The
list
of
potential
changes
includes
the
full
range
of
potential
changes
to
the
regulation
on
which
EPA
is
specifically
requesting
comment.
Each
potential
change
to
the
regulation
is
discussed
in
detail
in
the
corresponding
section
of
the
ANPRM.

B.
Uses
1.
Background
Section
131.10
of
the
current
regulation
describes
States'
and
authorized
Tribes'
responsibilities
for
designating
and
protecting
uses.
The
regulation
requires
that
States
and
Tribes
specify
the
water
uses
to
be
achieved
and
protected;
requires
protection
of
downstream
uses;
allows
for
sub­
category
and
seasonal
uses,
for
instance,
to
differentiate
between
cold
water
and
warm
water
fisheries;
sets
out
minimum
attainability
criteria;
lists
six
factors
of
which
at
least
one
must
be
satisfied
to
justify
removal
of
designated
uses
which
are
not
existing
uses;
prohibits
removal
of
existing
uses;
establishes
a
mandatory
upgrading
of
uses
which
are
existing
but
not
designated;
and
establishes
conditions
and
requirements
for
conducting
use
attainability
analyses.
These
provisions
make
a
distinction
between
existing
and
designated
uses
and
set
out
specific
requirements
to
ensure
protection
of
these
two
broad
use
categories.
Designated
uses
are
defined
as
those
uses
specified
in
water
quality
standards
for
each
water
body
or
segment
whether
or
not
they
are
being
attained.
EPA
interprets
existing
uses
as
those
uses
actually
attained
in
the
water
body
on
or
after
November
28,
1975
(
the
date
of
EPA's
initial
water
quality
standards
regulation),
whether
or
not
they
are
included
in
water
quality
standards.
40
CFR
131.3(
e).
Designated
uses
focus
on
the
attainable
condition
while
existing
uses
focus
on
the
past
or
present
condition.
Section
131.10
then
links
these
two
broad
use
categories
in
a
manner
which
intends
to
ensure
that
States
and
Tribes
designate
appropriate
water
uses,
reflecting
both
the
existing
and
attainable
uses
of
each
water
body.
For
this
discussion
it
is
important
to
consider
both
the
distinction
between
and
linkage
of
designated
and
existing
uses.
It
is
in
designating
uses
that
States
and
Tribes
establish
the
environmental
goals
for
their
water
resources,
and
it
is
in
designating
uses
that
States
and
Tribes
are
allowed
to
evaluate
the
attainability
of
those
goals.
Because
water
quality
standards
perform
the
dual
function
of
establishing
water
quality
goals
and
ultimately
serving
as
the
regulatory
basis
for
water
qualitybased
treatment
controls
and
strategies,
typically,
although
not
exclusively,
via
water
quality
criteria
protecting
those
uses,
a
State
or
Tribe
often
weighs
the
environmental,
social
and
economic
36749
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/
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No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
consequences
of
its
decisions
in
designating
uses.
The
regulation
allows
the
State
or
Tribe
some
flexibility
in
weighing
these
considerations
and
adjusting
these
goals
over
time.
Reaching
a
conclusion
on
the
uses
that
appropriately
reflect
the
potential
for
a
water
body,
determining
the
attainability
of
those
goals,
and
appropriately
evaluating
the
consequences
of
a
designation,
however,
can
be
a
difficult
and
controversial
task.
Appropriate
application
of
this
process
involves
a
balancing
of
environmental,
scientific,
technical,
and
economic
and
social
considerations
as
well
as
public
opinion
and
is
therefore
one
of
the
most
challenging
areas
of
the
current
regulation.
To
direct
this
decision
makingprocess
the
regulation
establishes
requirements
that
must
be
followed
when
designating
uses
or
concluding
that
attaining
a
use
is
infeasible.
When
performing
this
attainability
analysis,
a
State
or
Tribe
considers
physical,
chemical,
biological
and
economic
factors
that
may
limit
the
potential
for
achieving
the
goal
use.
EPA's
current
water
quality
regulation
effectively
establishes
a
``
rebuttable
presumption''
that
``
fishable/
swimmable''
uses
are
attainable
and
therefore
should
apply
to
a
water
body
unless
it
is
affirmatively
demonstrated
that
such
uses
are
not
attainable.
EPA
believes
that
the
rebuttable
presumption
policy
reflected
in
these
regulations
is
an
essential
foundation
for
effective
implementation
of
the
Clean
Water
Act
as
a
whole.
The
``
use''
of
a
water
body
is
the
most
fundamental
articulation
of
its
role
in
the
aquatic
and
human
environments,
and
all
of
the
water
quality
protections
established
by
the
CWA
follow
from
the
water's
designated
use.
This
approach
preserves
States'
and
Tribes'
paramount
role
in
establishing
water
quality
standards,
in
this
instance,
in
weighing
any
available
evidence
regarding
the
attainable
uses
of
a
particular
water
body.
The
rebuttable
presumption
approach
does
not
restrict
the
discretion
that
States
and
Tribes
have
to
determine
that
``
fishable/
swimmable''
uses
are
not,
in
fact,
attainable
in
a
particular
case.
Rather,
if
the
water
quality
goals
articulated
by
Congress
are
not
to
be
met
in
a
particular
water
body,
the
regulations
simply
require
that
such
a
determination
be
based
upon
a
credible,
``
structured
scientific
assessment''
of
use
attainability.
Because
there
is
a
presumption
that
the
uses
specified
in
sections
101(
a)(
2)
and
303(
c)
of
the
Clean
Water
Act
are
attainable
(
protection
and
propagation
of
fish,
shellfish
and
wildlife
and
recreation
in
and
on
the
water
[
101(
a)(
2)];
public
water
supplies,
propagation
of
fish
and
wildlife,
recreational
purposes,
agricultural
purposes,
and
navigation
[
303(
c)(
2)(
A)]),
the
criteria
for
overcoming
that
presumption
are
carefully
circumscribed.
The
economic
use
removal
test,
for
example,
requires
a
showing
that
the
cost
of
compliance
with
the
use(
s)
would
result
in
``
substantial
and
widespread
economic
and
social
impact.''
This
is
a
high
threshold
to
ensure
that
the
interim
goals
of
section
101(
a)(
2)
and
the
section
303(
c)
uses
are
not
abandoned
without
appropriate
cause.
The
general
construction
of
the
§
131.10
requirements
for
designating
uses,
supplemented
with
specific
Agency
guidance,
has
worked
well
in
most
situations
over
the
last
14
years,
and
the
use
designation
process
is
well
established
in
State
and
Tribal
water
quality
standards
programs.
There
are,
however,
a
number
of
new
issues
that
have
arisen
since
the
1983
regulation
was
promulgated.
Often
these
new
issues
are
associated
with
site­
specific
decision­
making,
and
EPA
expects
the
trend
toward
site­
specific
application
of
water
quality
standards
will
accelerate
as
States
and
Tribes
begin
implementing
watershed
protection
programs,
using
field
biological
information
to
more
precisely
describe
aquatic
communities
to
be
protected
or
restored,
and
applying
new
watershed
or
ecosystem­
specific
approaches
to
criteria
development.
As
explained
in
the
``
Objectives''
discussion
in
this
document,
one
of
the
principal
reasons
for
this
notice
is
to
determine
whether
or
not
the
current
regulation
is
sufficiently
flexible
to
accommodate
an
expected
shift
in
program
emphasis
beyond
chemical
contaminants
to
ecosystem
protection
and
watershed
approaches
that
will
necessarily
place
greater
emphasis
on
integrated
assessments
of
both
chemical
and
non­
chemical
stressors
and
watershed­
specific
decision­
making.
While
it
is
important
to
identify
potential
barriers
to
needed
flexibility,
commenters
should
identify,
as
well,
any
changes
or
clarification
that
may
be
needed
to
ensure
that
an
appropriate
level
of
national
consistency
is
maintained
across
and
within
all
jurisdictions.
In
this
section
of
the
notice,
EPA
seeks
comment
on
the
following
issues:
(
1)
refined
designated
uses
with
more
focus
on
watersheds
and
ecosystems,
(
2)
existing
uses,
(
3)
attainability
and
removal
of
designated
uses,
and
(
4)
alternatives
to
removal
of
designated
uses.
2.
Refined
Designated
Uses
The
current
regulation
at
40
CFR
131.10(
a),
based
on
section
303
of
the
CWA,
requires
that
States
and
authorized
Tribes
specify
appropriate
water
uses
to
be
achieved
and
protected,
taking
into
consideration
the
use
and
value
of
water
for
public
water
supplies,
protection
and
propagation
of
fish,
shellfish
and
wildlife,
recreation
in
and
on
the
water,
agricultural,
industrial,
and
other
purposes
including
navigation.
The
regulation
also
allows,
but
does
not
require,
States
and
Tribes
to
identify
more
specific
sub­
categories
of
these
general
use
categories.
Over
the
years,
States
and
Tribes
have
created
many
different
use
classification
systems
ranging
from
a
straightforward
replication
of
uses
specifically
listed
in
section
303
of
the
Act
to
more
complex
systems
that
express
designated
uses
in
very
specific
terms
or
establish
subclassifications
which
identify
different
levels
of
protection.
For
example,
some
States
simply
specify
``
water
supply''
as
a
use
classification
applicable
throughout
the
State
while
others
may
identify
several
specific
sub­
categories
related
to
the
quality
of
the
raw
water
supply
and
anticipated
treatment
requirements.
Similarly,
some
States
designate
general
``
aquatic
life''
uses
while
others
list
a
variety
of
subcategories
based
on
a
range
of
aquatic
community
types
which
may
include
descriptions
of
core
aquatic
species
representative
of
each
sub­
category.
Although
a
variety
of
approaches
have
evolved
and
become
established
in
State
and
Tribal
programs,
the
current
regulation
is
not
specific
about
the
level
of
precision
States
or
Tribes
must
achieve
in
designating
uses.
There
are
advantages
and
drawbacks
for
either
the
general
or
specific
use
classification
systems
and
it
is
not
clear
that
either
is
necessarily
superior
in
ensuring
full
protection
of
State
or
Tribal
water
quality.
There
is,
however,
a
need
for
the
use
designation
process,
whether
implementing
a
general
or
specific
classification
system,
to
clearly
articulate
and
differentiate
intended
levels
of
protection
with
enough
specificity
so
that
decision­
makers
can
appropriately
develop
and
implement
the
standards
on
a
site­
or
watershedspecific
basis
and
so
that
the
public
can
understand,
identify
with,
and
influence
the
goals
set
for
waters
they
care
about.
Lack
of
precision
in
uses
and
criteria
assigned
to
protect
those
uses
can
inadvertently
result
in
either
a
lesser
or
greater
level
of
protection
than
was
actually
intended
when
the
water
quality
standards
were
adopted.
Although
the
designated
use
specificity
36750
Federal
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/
Vol.
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No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
issue
may
apply
to
any
of
the
Section
303
general
use
categories,
it
may
be
most
relevant
for
aquatic
life
uses.
Aquatic
communities
can
vary
significantly
from
water
body­
to­
water
body.
As
noted
above,
however,
State
and
Tribal
use
classifications
generally
do
not
reflect
the
variability
among
aquatic
community
types
and
may
list,
instead,
very
general
descriptions
such
as
``
aquatic
life''
as
the
designated
use.
Where
this
is
the
case,
it
is
possible
that
measurable
changes
in
aquatic
community
composition
or
production
could
occur
at
a
specific
site
and
still
satisfy
the
definition
of
``
aquatic
life,''
unless
somewhere
in
its
process
the
State
or
Tribe
has
documented
information
about
its
specific
intent
in
applying
the
``
aquatic
life''
classification
to
each
water
body.
For
example,
an
activity
that
causes
the
discharge
of
sediment,
altering
the
physical
habitat
in
the
receiving
water
body,
could
result
in
a
measurable
change
in
aquatic
community
structure
and
function
(
e.
g.,
the
types
of
aquatic
species
found
in
that
segment).
Yet,
that
activity
may
arguably
satisfy
a
general
``
aquatic
life''
use
protection
requirement
simply
because
of
a
lack
of
specificity
in
the
regulatory
description
of
that
designated
use.
In
this
case,
lack
of
precision
in
the
designation
or
description
of
the
use
could
result
in
under
protection
of
the
resource,
unless
somewhere
in
the
State
or
Tribal
process
an
intended
level
of
protection
is
specified.
Alternatively,
lack
of
precision
in
uses
and
assigned
criteria
could
result
in
standards
that
are
over
protective,
resulting
in
application
of
unnecessary
control
requirements.
In
assigning
criteria
to
protect
general
use
classifications,
a
State
or
Tribe
must
ensure
that
the
criteria
are
sufficiently
protective
to
safeguard
the
full
range
of
waters
in
the
State
or
Tribe
(
i.
e.,
criteria
would
be
based
on
the
most
sensitive
use).
While
this
approach
will
result
in
full
protection
of
all
State
or
Tribal
waters,
the
approach
has
been
challenged,
especially
for
aquatic
life
uses,
where
evidence
suggests
that
the
general
use
and
criteria
will
require
controls
more
stringent
than
needed
to
protect
either
the
existing
or
potential
aquatic
community
for
a
specific
water
body.
Although
EPA
supports
broad
application
of
statewide
or
tribe­
wide
criteria
to
ensure
that
sensitive
uses
are
protected
where
site­
specific
information
is
lacking,
the
Agency's
current
thinking
is
that
there
is
a
growing
need
to
more
precisely
tailor
use
descriptions
and
criteria
to
match
site­
specific
conditions,
ensuring
that
uses
and
criteria
provide
an
appropriate
level
of
protection
which,
to
the
extent
possible,
is
neither
over
nor
under
protective.
This
concept
was
reflected
in
the
Agency's
1994
Combined
Sewer
Overflow
Policy
(
59
FR
18688).
The
level
of
protection
issue
is
one
of
both
use
and
criteria.
To
have
a
meaningful
effect,
a
more
precise
use
description
must
be
accompanied
by
more
focused
criteria,
appropriately
tailored
to
the
refined
use
description.
EPA
recognizes
that,
at
present,
national
or
statewide
or
tribe­
wide
criteria
generally
are
not
sufficiently
precise
to
distinguish
among
all
of
the
various
sub­
categories
of
uses.
As
water
quality
standards
issues
become
more
watershed­
specific
or
site­
specific,
however,
the
trend
will
very
likely
be
toward
more
specific
use
descriptions
and;
because
the
essential
purpose
of
the
criteria
is
to
describe,
evaluate
attainment
of,
and
protect
the
designated
use;
more
site­
specific
criteria
development.
A
potential
constraint
for
refining
the
aquatic
life
uses
would
be
the
resource
commitment
often
associated
with
developing
a
comprehensive
biological
database.
Because
of
the
resource
constraints,
it
may
be
difficult
for
a
State
or
Tribe
to
develop
designated
uses
(
or
use
descriptions)
for
each
segment
that
include
a
detailed
biological
description
of
the
aquatic
community
to
be
protected.
Simply
from
a
practical
standpoint,
it
may
be
more
workable
to
reserve
such
precise
determinations
for
watershed­
specific
decision­
making.
Therefore,
in
highlighting
the
issue
of
greater
specificity,
EPA
is
suggesting
that
one,
but
perhaps
not
the
only,
way
to
resolve
this
issue
is
to
mandate
much
greater
specificity
in
a
State
or
Tribal
use
classification
structure.
Obviously,
there
is
a
need
for
designated
use
descriptions
in
State
and
Tribal
regulation
to
be
defined,
at
a
minimum,
with
sufficient
specificity
to
ensure
existing
and
potential
uses
will
be
protected
and/
or
attained.
The
difficulty
is
in
striking
a
balance
between
specificity
sufficient
to
ensure
uses
are
appropriately
protected
and
flexibility
needed
to
allow
efficient
widespread
application
of
a
classification
system
to
all
State
or
Tribal
waters.
A
question
has
been
raised
about,
and
EPA
is
considering,
whether
or
not
the
current
regulation
and
guidance
provide
the
framework
needed
to
strike
the
appropriate
balance
and
the
guidance
on
when
and
how
to
refine
uses.

Aquatic
Life
An
issue
related
to
the
manner
in
which
States
and
Tribes
define
designated
aquatic
life
uses
is
the
occasional
confusion
expressed
between
the
actual
intent
of
the
CWA
section
101(
a)(
2)
interim
goals
and
the
``
fishable/
swimmable''
short
hand
expression
often
used
to
describe
those
interim
goals.
EPA
acknowledges
that
the
phrase
``
fishable/
swimmable''
does
not
fully
describe
the
intent
and
scope
of
the
CWA
section
101(
a)(
2)
interim
goals.
The
confusion
over
the
expression
``
fishable''
often
surfaces
where
there
is
an
action
aimed
at
removing
an
aquatic
life
use
from
a
particular
water
body
where
there
are
no
sport
or
commercial
fisheries.
In
these
instances,
an
argument
is
often
made
that
the
water
body
does
not
meet
the
``
fishable''
intent
of
the
section
101(
a)(
2)
interim
goals
because
the
water
body
naturally
supports
only
``
minnows''
and/
or
aquatic
invertebrates.
EPA
believes
this
is
an
unacceptable
argument
for
removing
an
aquatic
life
designated
use
or
excluding
an
aquatic
life
designated
use.
As
explained
in
EPA's
Questions
and
Answers
on
Antidegradation
(
USEPA,
1985,
p.
3),
the
Agency
considers
the
protection
afforded
by
standards
to
focus
on
an
appropriately
representative
aquatic
community
whether
or
not
that
community
includes
sport
or
commercial
fish:

The
fact
that
sport
or
commercial
fish
are
not
present
does
not
mean
that
the
water
may
not
be
supporting
an
aquatic
life
protection
function.
An
existing
aquatic
community
composed
entirely
of
invertebrates
and
plants,
such
as
may
be
found
in
a
pristine
tributary
alpine
stream,
should
be
protected
whether
or
not
such
a
stream
supports
a
fishery.
Even
though
the
shorthand
expression
``
fishable/
swimmable''
is
often
used,
the
actual
objective
of
the
Act
is
to
restore
the
chemical,
physical
and
biological
integrity
of
our
Nation's
waters
(
Section
101(
a)).
The
term
``
aquatic
life''
would
more
accurately
reflect
the
protection
of
the
aquatic
community
that
was
intended
in
Section
101(
a)(
2)
of
the
Act.

Thus,
EPA's
current
interpretation
of
the
regulation
means
that
the
Agency
will
not
approve
State
or
Tribal
action
to
exclude
aquatic
life
protection
based
on
a
conclusion
that
a
water
body
does
not
support
a
``
fishery'',
implying
a
sport
or
commercial
fishery.
EPA's
current
thinking
is
that
it
would
improve
the
regulatory
text
to
reflect
this
interpretation
explicitly.
More
specific
to
this
discussion
of
refined
designated
uses
is
the
question
of
whether
or
not
the
Agency
should
mandate
that
a
minimum
``
aquatic
life''
use
sub­
category
or
sub­
categories
be
included
in
all
State
or
Tribal
designated
use
classification
systems
to
ensure
appropriate
protection
of
waters
36751
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
which
do
not
support
commercial
or
sport
fisheries
(
or
any
fish).

Refined
Designated
Uses
and
Use
Attainability
Requirements
There
is
one
additional
issue
related
to
the
refined
designated
use
discussion
that
should
be
addressed.
A
question
has
been
raised
about
the
applicability
of
the
use
attainability
requirements
when
establishing
refined
designated
uses
(
with
particular
emphasis
of
aquatic
life
uses).
The
question
raised
is:
since
refined
designated
uses
may
be
less
inclusive
than
broad
designations,
will
EPA
consider
development
of
a
more
refined
use
description
to
be
a
change
in
use
subject
to
the
use
attainability
requirements?
Under
current
regulation,
the
combination
of
a
new
use
sub­
category
and
less
stringent
criteria
triggers
the
use
attainability
requirements
in
§
131.10
of
the
Federal
regulation
(
see
§
131.10(
j)(
2)).
However,
it
is
possible
that
under
certain
circumstances,
this
requirement
could
be
modified.
Such
a
modification
would
focus
on
the
kind
of
information
that
should
accompany
any
refined
use
classification
based
on
a
more
precise
biological
description,
whether
or
not
formal
use
attainability
assessment
requirements
apply.
Essentially,
there
are
two
issues
to
be
addressed:
(
1)
does
the
refined
description
of
the
aquatic
community
reflect
the
reference
condition
(
i.
e.,
natural
states)
for
the
kinds
of
waters
to
which
the
new
classification
is
to
be
applied?
and
(
2)
are
any
newly
proposed
criteria
scientifically
defensible?
These
are
basic
questions
which
would
have
to
be
addressed
whether
or
not
the
use
attainability
requirements
were
invoked.
As
a
result,
a
proposal
to
refine
use
categories
will
have
to
be
accompanied
by
a
rationale
explaining
how
it
was
determined
that
the
proposed
biological
description
appropriately
reflects
the
potential
for
waters
to
which
the
new
sub­
classification
is
to
be
applied.
If
warranted,
this
refined
description
can
then
serve
as
the
basis
for
deriving
defensible
and
appropriate
criteria
specific
to
the
new
sub­
classification.

Request
for
Comment
Refining
Use
Designations
EPA
seeks
comment
on
the
following
questions:
1.
The
current
regulation
is
not
specific
about
the
level
of
precision
States
or
Tribes
must
achieve
in
designating
uses.
The
regulation
allows
for
subcategories
of
uses,
but
does
not
mandate
such
an
approach.
Should
the
regulation
be
revised
to
promote
or
require
greater
specificity
in
designated
uses,
particularly
for
aquatic
life
uses,
to
support
watershed­
specific
decisionmaking
such
as
is
anticipated
in
implementing
watershed
or
place­
based
initiatives?
2.
Where
a
State
or
Tribe
utilizes
broadly­
defined
designated
uses,
could
the
desired
level
of
specificity
be
adequately
addressed
in
State
or
Tribal
standards
that
clearly
articulate
the
intent
of
the
designated
uses
as
they
would
apply
to
specific
waters
of
the
State
or
Tribe?
3.
If
EPA
were
to
specify
a
required
level
of
precision
in
establishing
use
categories,
what
factors
should
be
considered
in
prescribing
a
level
of
specificity?
That
is,
what
factors
should
be
considered
in
striking
a
balance
between
specificity
sufficient
to
ensure
uses
are
afforded
an
appropriate
level
of
protection
and
flexibility/
efficiency
needed
to
allow
widespread
application
of
the
classification
system?
4.
At
a
minimum,
should
the
regulation
require
that
State
and
Tribal
aquatic
life
use
categories
include
a
subcategory
or
sub­
categories
that
may
be
assigned
to
protect
aquatic
communities
that
do
not
include
a
``
fishery''?
Alternatively,
should
the
regulation
explicitly
reflect
EPA's
current
interpretation
of
the
regulations
to
the
effect
that
State
and
Tribal
aquatic
life
classification
systems
protect
a
range
of
aquatic
communities
whether
or
not
there
are
sport
or
commercial
fish
(
or
any
fish)
present?
5.
Should
the
use
attainability
requirements
in
131.10(
j)(
2)
be
modified
to
recognize
situations
where
scientifically
defensible
less
stringent
criteria
may
be
appropriate
for
refined
uses
which
reflect
the
reference
condition
for
particular
waters?

3.
Existing
Uses
a.
Protection
of
Existing
Uses.
The
requirement
to
protect
existing
uses
is
addressed
in
two
places
in
the
current
regulation
 
Section
131.10,
designation
of
uses
and
Section
131.12,
antidegradation.
(
see
discussion
of
antidegradation,
``
tier
1'',
in
section
III.
D
of
this
document)
As
discussed
in
the
background
section
above,
the
regulation
defines
``
existing
uses''
as
``
those
uses
actually
attained
in
the
water
body
on
or
after
November
28,
1975,
whether
or
not
they
are
included
in
the
water
quality
standards.''
(
40
CFR
131.3(
e))
As
a
result,
the
focus
of
existing
uses,
is
on
the
past
or
present
condition
of
the
water
body.
Furthermore,
by
establishing
requirements
prohibiting
the
removal
of
existing
uses
and
ensuring
those
uses
will
be
appropriately
recognized
in
State
and
Tribal
water
quality
standards,
the
current
regulation
ensures
that
the
better
of
the
past
or
present
condition,
at
a
minimum,
will
be
maintained
and
protected.
Determining
whether
or
not
an
existing
use
has
occurred
in
the
past
or
is
currently
in
place
is
not
always
a
straightforward
task,
however,
and
over
the
years,
a
number
of
questions
have
been
raised
about
exactly
what
the
``
existing
use''
provisions
in
131.10
require.
These
questions
generally
fall
into
two
categories:
(
1)
what
is
the
link
between
existing
uses
and
the
State
or
Tribal
use
classification
system?
and
(
2)
what
is
the
relationship
between
existing
uses,
existing
water
quality
and
potential
uses,
i.
e.
uses
that
may
be
attainable
in
the
water
body
whether
or
not
those
uses
are
presently
designated
for
the
water
body
or
are
presently
being
attained?
The
first
question
addresses
the
relationship
between
the
existing
use
protection
provisions
in
Section
131.10
and
State
or
Tribal
use
classification
systems.
There
appears
to
be
some
confusion
on
this
point.
The
confusion
seems
to
center
on
what
may
appear
to
be
conflicting
mandates
 
protect
what
is
there
and
allow
no
further
erosion
of
water
quality,
and
appropriately
designate
the
existing
use
in
regulation
using
the
established
classification
system.
The
existing
use
definition
and
the
requirement
that
existing
uses
be
protected
suggests
to
some
that
the
description
of
existing
uses
is
constrained
by
the
way
in
which
a
State
or
Tribe
has
described
its
designated
uses
in
its
classification
system.
That
is,
they
argue
that
an
existing
use,
to
be
adequately
protected,
needs
to
fit
into
one
of
the
categories
or
sub­
categories
established
in
State
or
Tribal
regulation,
and
as
a
result,
a
decision
about
whether
or
not
a
use
is
``
existing''
is
likewise
constrained
by
the
use
descriptions
and
criteria
established
in
that
classification
system.
For
purposes
of
Section
131.10,
this
is
generally
the
case.
Again,
this
Section
of
the
Federal
regulation
establishes
two
requirements
with
respect
to
existing
use
protection:
(
1)
a
prohibition
against
removal
of
a
designated
use
where
that
use
is
determined
to
be
an
existing
use,
and
(
2)
a
requirement
that
existing
uses
be
protected
by
State
or
Tribal
regulation.
To
ensure
a
workable
process,
EPA
interprets
Section
131.10
as
necessarily
recognizing
a
linkage
between
the
existing
use
protection
provisions
and
the
established
State
or
Tribal
use
classification
system.
This
interpretation
of
the
regulatory
framework,
however,
also
presumes
a
responsibility
on
the
part
of
a
State
or
Tribe
to
establish
a
classification
system
that
is
sufficiently
flexible
and/
or
36752
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
encompassing
to
assure
an
appropriate
level
of
protection
for
the
anticipated
range
of
existing
uses
(
see
discussion
on
refined
designated
uses
in
this
chapter).
As
explained
earlier
in
the
discussion
on
refined
designated
uses,
a
variety
of
use
classification
systems
has
evolved
and
become
established
in
State
and
Tribal
programs.
Although
there
are
likely
some
advantages
to
a
more
refined
use
classification
system
when
it
comes
to
protecting
existing
uses
(
more
precise
categories
in
which
to
fit
the
existing
use),
such
a
system
may
not
be
necessary
as
long
as
the
State
or
Tribal
standards
clearly
articulate
the
intended
and
appropriate
level
of
protection
for
existing
uses
(
again,
see
discussion
of
refined
designated
uses).
The
following
example
illustrates
the
point.
An
acid
bog
is
a
water
body
type
which
may
be
fairly
widespread
but
which,
as
a
classification
type,
may
not
appear
in
many
State
or
Tribal
standards.
Where
the
aquatic
characteristics
of
an
acid
bog
are
discovered
to
constitute
an
existing
use,
a
State
or
Tribe
could:
(
1)
establish
a
classification
type
and
criteria
for
acid
bogs
to
ensure
appropriate
protection
by
way
of
a
specific
designation,
or
(
2)
classify
the
bog
within
the
existing,
general
classification
system,
e.
g.,
warm
water
aquatic
life,
and
adopt
any
needed
site­
specific
criteria
to
ensure
the
existing
nature
and
quality
of
this
specific
water
resource
is
protected.
Either
approach
can
result
in
an
appropriate
level
of
protection
and
there
may
not
be
a
need
for
States
or
Tribes
to
include
an
``
acid
bog''
water
body
type
in
their
classification
system.
Under
either
approach
the
standards
must
articulate
clearly
the
intended
and
appropriate
level
of
protection,
ensuring
protection
of
the
existing
use.
It
is
also
important
to
remember
that
the
existing
use
provisions
in
both
§
§
131.10
and
131.12
must
be
considered
together.
The
classification
requirements
in
§
131.10
ensure
that
all
existing
uses
will
be
recognized
and
protected
through
appropriate
classification
of
those
water
bodies
in
the
standards
(
and/
or
application
of
appropriate
site­
specific
criteria
where
the
existing
classification
system
is
broadly
constructed).
The
antidegradation­
based
existing
use
protection
provision
guarantees
that
individual
activities
on
individual
water
bodies
will
be
examined
to
ensure
those
activities
will
not
eliminate
existing
uses,
whether
or
not
those
uses
are
currently
recognized
in
the
State
or
Tribal
standards.
The
antidegradation
provisions,
through
the
general
requirement
that
existing
uses
be
protected,
ensure
immediate
protection
from
specific
activities
which
may
threaten
the
existing
use,
and
the
classification
requirements
ensure
recognition
and
longer­
term
protection
from
any
present
or
future
stressors
through
specific
designation
in
the
standards.
Both
these
provisions
apply
and
should
not
be
considered
in
isolation.
Together
they
constitute
the
existing
use
protection
requirements,
ensuring
the
existing
uses
and
water
quality
to
support
those
uses
are
maintained
and
protected.
The
second
question
addresses
the
relationship
between
existing
uses,
existing
water
quality
and
potential
uses.
The
Agency's
guidance,
Questions
and
Answers
on
Antidegradation,
August,
1985
(
Notice
of
Availability,
50
FR
34546,
August
26,
1985
[
included
as
appendices
to
Water
Quality
Standards
Handbook,
cited
above])
addresses
this
issue,
in
part.
The
answer
to
``
question
7''
states:
``
an
existing
use
can
be
established
by
demonstrating
that
fishing,
swimming,
or
other
uses
have
actually
occurred
since
November
28,
1975,
or
that
the
water
quality
is
suitable
to
allow
such
uses
to
occur
(
unless
there
are
physical
problems
which
prevent
the
use
regardless
of
water
quality).''
Using
an
example
of
a
healthy
shellfish
community
which
is
not
currently
being
harvested,
the
answer
goes
on
to
explain
that
the
existence
of
a
use
(
past
or
present)
is
not
dependent
solely
upon
a
demonstration
that
the
use
is
being
satisfied
in
a
functional
sense
(
i.
e.,
in
this
case,
the
shellfish
harvested).
In
this
example,
``
shellfish
harvesting''
is
considered
an
existing
use,
even
though
there
is
presently
no
harvesting
underway,
because
the
water
quality
and
habitat
support
a
healthy
shellfish
community
suitable
for
harvesting.
The
answer
further
explains
that
to
assume
otherwise
``*
*
*
would
be
to
say
that
the
only
time
an
aquatic
protection
use
`
exists'
is
if
someone
succeeds
in
catching
fish.''
As
illustrated
in
this
example,
the
existing
use
question
must
address
both
the
current
or
past
functional
use
and
the
current
or
past
(
since
November
28,
1975)
water
quality,
and
the
intent
of
the
regulation
is
to
ensure
the
existing
use
and
the
water
quality
necessary
to
support
that
use
are
maintained
and
protected.
Thus,
in
this
example,
the
shellfish
harvesting
use
is
to
be
protected
by
designated
uses
in
water
quality
standards.
The
shellfish
example
is
a
good
one
in
that
it
clearly
illustrates
EPA's
position
that
an
existing
use
finding
can
be
made
either
where
the
use
is
or
has
been
``
actually
attained''
or
where
the
water
quality
necessary
to
support
the
use
is
in
place
even
if
the
use,
itself,
is
not
currently
established,
as
long
as
other
site­
specific
factors,
for
example
physical
problems
like
flow
or
substrate,
would
not,
despite
the
suitable
water
quality,
prevent
attainment
of
the
use.
The
``
other
factors''
caution
is
important
in
understanding
EPA's
position
on
existing
uses.
In
making
an
existing
use
determination,
there
is
a
link
between
the
use
and
water
quality.
To
be
considered
an
existing
use,
the
use
must
have
been
actually
attained
in
the
past,
is
now
attained
or
water
quality
is
sufficient
to
support
the
use.
However,
for
some
sites,
water
quality,
alone,
may
be
an
insufficient
basis
for
making
an
existing
use
finding
if
there
are
other
factors
that
would
prohibit
the
use
from
taking
place
regardless
of
the
quality
of
the
water
at
a
site.
In
the
shellfish
example,
the
necessary
water
quality
is
present,
and
there
are
no
obvious
limiting
factors
which
would
prohibit
present
or
future
shellfish
harvesting.
Although
this
example
is
useful
in
illustrating
important
principles
in
implementing
existing
use
protection
requirements,
it
is
a
rather
straightforward
example.
An
appropriate
resolution
of
the
existing/
designated
use
issue
may
be
somewhat
less
clear­
cut
where
either
the
existing
water
quality
or
the
existing
use
is
marginal
(
i.
e.,
it
is
difficult
to
determine
whether
or
not
the
use
is
actually
attained,
or
whether
or
not
there
are
factors,
other
than
water
quality,
that
could
prohibit
the
use).
It
is
in
addressing
these
situations
that
questions
have
been
raised
about
what
the
current
regulation
requires.
A
principal
difficulty
in
addressing
these
questions
may
lie
in
resolving
the
linkage
between
the
present
and
past
conditions
protected
by
the
``
existing
uses''
provisions
and
the
attainable
or
potential
condition
protected
by
``
designated
uses''
provisions.
It
may
be
useful
to
evaluate
this
issue
by
considering
the
link
between
existing
and
designated
uses
established
in
the
current
regulation.
Obviously,
any
decision
about
whether
or
not
a
use
is
an
``
existing
use''
must
be
a
water
body­
specific
determination.
The
existing
use
determination
is,
therefore,
site­
specific,
and
decisions
should
consider
water
quality
and
other
limiting
factors
such
as
the
physical
habitat
specific
to
a
particular
water
body.
A
few
examples
may
help
illustrate
the
issue.
A
somewhat
common
existing
use
question
applies
to
primary
contact
recreation:
if
a
few
people
on
a
few
occasions
``
swim''
in
a
water
body
that
does
not
have
the
quality
or
physical
characteristics
to
support
swimming,
is
this
an
existing
use,
even
if
the
water
body
is
posted
``
no
swimming''
due
to
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/
Tuesday,
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7,
1998
/
Proposed
Rules
bacterial
contamination
and
lacks
the
physical
features
to
actually
support
swimming?
The
straightforward
answer
to
this
question
is
that
``
swimming''
is
not
an
existing
use
because
the
present
(
or
past)
condition
does
not
support
that
use.
This
conclusion
is
based
on
the
very
limited
actual
``
use''
and,
more
importantly,
the
lack
of
suitable
water
quality
and
physical
characteristics
that
would
support
a
recreational
swimming
use
now
or
in
the
future
(
as
determined
by
the
water
quality
requirements
and
recreational
swimming
considerations,
including
safety
considerations,
in
the
State
or
Tribal
classification
system
for
primary
contact
recreation).
A
question
has
been
raised
as
to
how
to
interpret
the
regulation
in
the
context
of
this
example.
One
could
determine
that
because
the
water
body
is
not
suitable
for
swimming,
and
has
not
been
since
1975,
primary
contact
recreation
is
not
an
existing
use.
Alternatively,
one
could
determine
primary
contact
recreation
to
be
an
existing
use
because
the
water
body
was
actually
used
for
swimming,
even
though
the
use
was
occasional
and
water
quality
and
physical
characteristics
were
not
acceptable
to
support
such
a
use.
EPA
believes
the
first
alternative
is
the
better
interpretation
of
Agency
regulations
and
guidance
in
this
example,
because
the
use
is
not
established
and
the
water
quality
and
other
factors
would
appear
to
prohibit
actually
attaining
a
recreational
swimming
use.
Stating
that
this
is
an
appropriate
interpretation
of
the
regulation
means
that
EPA
would
not
object
if
a
State
or
Tribe
reached
a
conclusion,
in
a
similar
case,
that
this
was
not
an
existing
use.
As
noted
above,
however,
existing
use
decisions
are
very
site­
specific,
and
it
is
possible
that,
on
a
specific
water
body
under
similar
circumstances,
a
different
conclusion
could
be
reached
by
a
State
or
Tribe
based
on
public
comment
at
a
hearing
and
a
decision
to
take
a
protective
approach
to
the
incidental
use
for
that
specific
resource.
The
Federal
requirements
do
not
prohibit
a
State
or
Tribe
from
taking
a
more
protective
approach
than
would
be
required
by
the
water
quality
standards
regulation.
Although,
in
the
above
example,
a
State
or
Tribe
could
conclude
that
primary
contact
recreation
is
not
an
existing
use,
it
may
well
be
an
attainable
use
that
must
be
protected
as
a
designated
use
by
the
State's
or
Tribe's
water
quality
standards.
This
finding
would
depend
on
whether
the
physical
condition
of
the
water
body
is
suitable
for
swimming
and
whether
the
water
quality
problems
limiting
the
use
are
controllable.
(
See
40
CFR
131.10(
j)
and
discussion
on
use
attainability
analysis
below).
The
point
is
that,
although
the
existing
use
provisions
most
directly
address
past
or
present
conditions,
decisions
about
existing
uses
generally
are
not
made
in
isolation.
With
respect
to
uses
contained
in
CWA
Section
101(
a)(
2),
the
regulation
links
existing
and
designated
uses,
and
it
may
be
useful
to
view
these
provisions
as
a
continuum
in
examining
the
broader
question
of
use
protection.
Some
States
and
Tribes
have
recognized
that
continuum
in
developing
use
attainability
guidance
for
recreational
uses
which
includes
questions
about
the
actual
use,
existing
water
quality,
water
quality
potential,
recreational
facilities,
location,
safety
considerations,
physical
conditions
of
the
water
body,
and
access
Note:
access
here
means
restricted
access,
as
in
fenced
property;
access
is
not
intended
to
suggest
the
``
remoteness''
of
the
water
body;
in
EPA's
view,
remoteness
is
not
a
valid
basis
for
an
attainability
decision
on
recreation.

When
all
of
these
factors
are
considered,
the
adopted
water
quality
standards
are
consistent
with
both
the
existing
and
designated
use
provisions.
For
example,
suppose
a
city
has
created
a
greenway
along
a
stream
that
receives
wastewater
effluent
upstream
of
the
greenway
and
has
posted
``
no
swimming''
signs.
The
greenway
attracts
children
leading
to
the
inevitable
``
unauthorized''
swimming.
If
the
physical
condition
of
the
stream
is
suitable
for
swimming,
the
swimming
occurs
on
a
frequent
basis
and
the
greenway
provides
recreational
facilities
and
access,
the
only
factor
limiting
the
use
may
be
a
water
quality
problem
that
in
the
judgement
of
the
State
or
Tribe
can
be
controlled
to
achieve
the
primary
contact
use.
The
linkage
between
existing
and
designated
uses
encourages
the
evaluation
of
this
full
suite
of
factors
in
making
a
decision
about
whether
or
not
primary
contact
recreation
should
be
protected.
A
similar
existing
use
question
is
often
raised
for
aquatic
life
uses
where
the
existing
aquatic
community
is
impaired
as
a
result
of
marginal
water
quality.
A
common
example
in
the
western
part
of
the
country
is
a
mountain
stream
impaired
by
historic
hard
rock
mining
(
with
the
impacts
occurring
well
before
November
28,
1975).
Although
the
physical
condition
of
the
stream
may
represent
ideal
trout
habitat,
the
trout
population
may
be
severely
limited,
in
poor
condition
or
absent
as
a
result
of
the
toxic
effects
of
metals.
In
its
classification
system,
however,
a
State
or
Tribe
may
describe
and
designate
this
type
of
stream
as
a
``
salmonid
spawning''
use
based
on
its
physical
habitat
and
potential.
For
streams
such
as
these,
where
a
few
adult
trout
are
present
but
there
is
no
evidence
of
younger
age
classes,
the
question
is
asked
 
is
this
an
existing
``
salmonid
spawning''
use?
Again,
the
appropriate
answer,
based
on
EPA
regulations
and
guidance,
is
that
this
is
not
an
existing
use
(
although
it
may
nonetheless
be
an
appropriate
designated
use
if
it
has
the
potential
to
support
salmonid
spawning).
The
current
use,
matching
the
classification
description,
is
absent,
and
the
limiting
water
quality
problems
have
been
in
existence
prior
to
November
28,
1975.
(
This
does
not
mean,
necessarily,
there
is
not
some
existing
aquatic
life
use
which
would
then
serve
as
the
regulatory
``
floor''
for
this
water
body;
see
the
``
limited''
aquatic
life
use
discussion
in
the
use
attainability
analysis
discussion
in
this
section
below
and
the
``
tier
1''
discussion
in
the
antidegradation
section,
III.
D)
As
in
the
``
swimming''
example,
however,
there
can
be
a
gradation
of
conditions,
and
occasionally
it
may
be
difficult
to
draw
a
bright
line
and
conclude,
with
confidence,
that
this
is
where
the
existing
use
begins.
In
situations
similar
to
this
impaired
stream
example,
where
the
existing
water
quality
problems
are
considered
controllable
by
the
State
or
Tribe,
arguments
have
been
made
on
both
sides
of
the
existing
use
issue:
the
salmonid
spawning
use
is
not
existing,
or
the
salmonid
spawning
use
is
in
place,
albeit
currently
at
an
impaired
level.
Disputes
about
the
correct
interpretation
of
Agency
guidance
become
even
more
difficult
to
resolve
where
the
existing
impacts
to
water
quality
are
not
as
great
as
those
in
the
above
example.
Often
streams
impacted
by
historical
mining,
such
as
the
one
described
above,
are
headwater
streams.
As
the
water
moves
downstream,
clean
water
tributaries
reduce
the
effect
of
the
metals
contamination,
and
fish,
in
number,
begin
to
move
into
these
``
improved''
waters.
Nevertheless,
many
such
streams
would
be
considered
impaired
when
compared
to
unaffected,
similar
waters
(
reference
streams).
And,
despite
supporting
``
fairly
good
numbers''
of
trout,
the
existing
water
quality
in
such
streams
often
exceeds
the
chronic
and,
occasionally,
acute
standards
for
metals.
In
situations
such
as
these,
States
and
Tribes
have
had
difficulty
in
reaching
conclusions
about
whether
or
not
an
existing
use,
matching
the
classification,
is
in
place.
Because
States
and
Tribes
may
evaluate
existing
uses
when
they
are
designating
uses,
threshold
existing
use
36754
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Register
/
Vol.
63,
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129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
determinations
may
lead
to
questions
about
the
potential
for
the
water
body
and
the
appropriate
designated
uses
for
it.
EPA's
current
interpretation
is
that
the
existing
use
should
be
identified
either
where
the
use
has
taken
place
or
the
water
quality
sufficient
to
support
the
use
has
existed
since
November
28,
1975,
or
both.
That
is
to
say,
State
and
Tribal
existing
use
decisions
can
be
based
on
a
finding
that
the
use,
as
defined
in
the
classification
system,
and/
or
the
water
quality
needed
to
support
the
use
is
in
place
(
and
there
are
no
other
factors
that
would
prohibit
actually
attaining
the
use).
This
interpretation
does
not
fully
address
the
issue
of
partially
impaired
uses.
Thus,
a
fuller
explanation
may
be
needed
in
the
regulation
or
policy
of
how
that
interpretation
is
applied
where
the
use
or
the
water
quality
may
be
somewhat
impaired.
EPA
is
considering
whether
changes
to
the
regulation
or
additional
guidance
is
needed
to
explain
the
Agency's
position
and
to
offer
direction
in
making
such
determinations.

Request
for
Comment
on
Existing
Uses
EPA
seeks
comment
on
the
following
questions:
1.
Does
EPA
need
to
further
clarify
the
existing
use
protection
provisions
in
§
131.10,
more
clearly
explaining
that
existing
uses
are
defined
by
the
uses
made
of
water
bodies
and
existing
water
quality,
where
that
quality
is
or
was
sufficient
to
allow
the
use
to
occur
(
and
there
are
no
other
limiting
factors)?
If
so,
will
the
clarification
require
a
regulatory
amendment
or
can
the
needed
clarification
be
accomplished
in
Agency
policy
or
guidance?
2.
Does
EPA
need
to
expand
its
guidance
to
explain
how
the
current
regulation
addresses
existing
use
decisions
where
there
is
some
semblance
of
a
use
even
though
the
water
quality
is
insufficient
to
support
the
use
in,
for
example
a
safe
or
healthful
manner?
Should
this
additional
guidance
clarify
the
linkage
between
existing
and
designated
uses?
3.
Should
the
regulatory
definition
of
``
existing
use''
at
40
CFR
131.3(
e)
be
modified?
If
so,
how?
4.
Use
Attainability.
a.
Attainability
of
Uses.
States
and
Tribes
may
remove
a
designated
use,
that
is
not
an
existing
use,
if
they
can
demonstrate
that
attaining
the
designated
use
is
infeasible.
(
40
CFR
131.10(
g))
The
current
regulation
identifies
the
factors
that
must
be
considered
in
making
such
a
demonstration.
As
explained
in
the
regulation,
existing
uses,
by
definition,
are
attainable
and
must
be
protected
by
designated
uses
in
water
quality
standards
(
40
CFR
131.10(
h)(
1),
131.10(
i)
and
131.12(
a)(
1)).
Further,
at
a
minimum,
uses
are
considered
attainable
if
they
can
be
achieved
by
implementing
effluent
limits
required
under
Sections
301(
b)
and
306
of
the
Clean
Water
Act
(
Act)
and
by
implementing
cost­
effective
and
reasonable
best
management
practices
(
BMPs)
for
nonpoint
source
control.
(
40
CFR
131.10(
h)(
2)).
These
existing
uses,
technology
and
BMP
provisions
establish
the
basic
regulatory
threshold
test
for
what
the
attainable
use
of
a
water
body
is
and
thus
what
the
minimum
use
designation
for
the
particular
water
body
must
be.
Where
either
the
use
is
existing
or
the
use
can
be
attained
through
implementation
of
Clean
Water
Act
technology
requirements
and/
or
implementation
of
applicable
State
requirements
regarding
BMPs
for
nonpoint
source
control,
40
CFR
131.10(
h)
establishes
that
the
use
is
attainable
and
must
be
designated.
Once
a
use
is
designated,
it
is
presumed
to
be
attainable
and
may
not
be
removed
(
downgraded)
unless
the
State
or
Tribe
can
demonstrate
that
attaining
the
designated
use
is
not
feasible
based
on
one
of
the
six
use
removal
criteria
(
40
CFR
131.10(
g)).
Therefore,
uses
are
considered
attainable
if:
(
1)
the
use
is
existing;
(
2)
the
use
can
be
attained
through
application
of
CWA
technology
requirements
and/
or
State
or
Tribe
required
BMPs;
or,
(
3)
none
of
the
use
removal
criteria
is
satisfied.
EPA
has
in
the
past
recommended
that
these
use
removal
criteria
referenced
under
number
3
above,
serve
as
additional
tests,
over
and
above
numbers
1
and
2
above,
for
determining
when
a
use
is
attainable.
Clearly
these
use
removal
criteria
(
131.10(
g))
are
designed
to
determine
whether
a
use
is
attainable
and
therefore
can
serve
that
purpose
equally
effectively
when
considering
whether
to
remove
a
designated
use
(
the
situation
where
they
are
clearly
required
to
be
used)
and
when
considering
whether
a
use
is
attainable
and
should
be
designated.
The
discussion
below
on
use
attainability
analysis
(
UAA)
and
non
section
101(
a)(
2)
uses
further
discusses
the
relationship
between
designation
of
attainable
uses,
UAAs,
and
the
analysis
required
to
justify
use
removal.
That
discussion
solicits
comment
on
whether
the
use
removal
criteria
at
§
131.10(
g),
in
addition
to
being
the
regulatory
justifications
for
use
removal,
should,
consistent
with
EPA's
interpretation
of
the
regulation,
be
included
in
the
basic
elements
of
a
UAA.
Despite
what
EPA
believes
are
fairly
clear
guidelines
in
the
current
regulation
and
guidance,
questions
have
been
raised
about
EPA's
minimum
attainability
requirements.
The
Agency's
current
thinking
is
that
basic
attainability
requirements,
the
methods
for
demonstrating
attainability,
the
circumstances
under
which
attainability
analysis
must
be
done,
and
what
that
analysis
must
consist
of
should
be
clarified
in
the
regulation.
b.
Removal
of
Designated
Uses.
The
regulation
(
at
40
CFR
131.10(
g))
specifies
that
States
and
Tribes
may
remove
a
designated
use
which
is
not
an
existing
use
if
attainment
of
a
use
is
not
feasible
due
to
the
following:
(
1)
Naturally
occurring
pollutant
concentrations
prevent
the
attainment
of
a
use;
or,
(
2)
Natural,
ephemeral,
intermittent,
or
low
flow
conditions
or
water
levels
prevent
the
attainment
of
the
use,
unless
these
conditions
may
be
compensated
for
by
the
discharge
of
sufficient
volume
of
effluent
discharges
without
violating
State
or
Tribal
water
conservation
requirements
to
enable
uses
to
be
met;
or,
(
3)
Human
caused
conditions
or
sources
of
pollution
prevent
the
attainment
of
the
use
and
cannot
be
remedied
or
would
cause
more
environmental
damage
to
correct
than
to
leave
in
place;
or;
(
4)
Dams,
diversions
or
other
types
of
hydrological
modifications
preclude
the
attainment
of
the
use,
and
it
is
not
feasible
to
restore
the
water
body
to
its
original
condition
or
operate
such
modification
in
a
way
that
would
result
in
the
attainment
of
a
use;
or,
(
5)
Physical
conditions
related
to
the
natural
features
of
the
water
body,
such
as
the
lack
of
a
proper
substrate,
cover,
flow,
depth,
pools,
riffles,
and
the
like,
unrelated
to
water
quality,
preclude
attainment
of
aquatic
life
protection
uses;
or,
(
6)
Controls
more
stringent
than
those
required
by
Sections
301(
b)
and
306
of
the
Act
would
result
in
substantial
and
widespread
economic
and
social
impact.
The
use
removal
criteria
were
included
in
the
regulation
to
address
those
circumstances
where
the
attainability
of
certain
uses
would
be
precluded
by
conditions
over
which
the
water
quality
protection
provisions
in
the
regulation
had
little
or
no
control.
The
uncontrollable
conditions
considered
most
likely
to
limit
attainability
were:
natural
water
quality
or
habitat
limitations,
irretrievable
human­
caused
contamination
or
conditions,
or
insupportable
economic
and
social
costs.
These
general
36755
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
conditions,
then,
formed
the
basis
for
the
six
use
removal
criteria.
Although
EPA
believes
the
use
removal
criteria
have
functioned
reasonably
well,
the
growing
number
and
reoccurring
nature
of
the
questions
raised
about
these
criteria
have
convinced
EPA
of
the
need
to
review
this
central
element
of
the
program.
Some
have
argued
that
the
six
criteria
and
their
interpretation
are
overly
stringent,
making
any
proposal
to
remove
a
designated
use
futile
even
where
a
use
was
``
mistakenly''
designated.
Others
argue
that
the
use
removal
criteria
and
their
interpretation
are
overly
generous,
granting
the
possibility
of
use
removal
where
the
principal
stressor
is
a
condition
which
should
not
be
immune
from
the
water
quality
protection
provisions
in
the
federal
regulation
(
operation
of
dams
is
one
example
used
in
arguing
this
position).
Others
complain
that
there
seems
to
be
no
national
consistency
in
the
way
the
use
removal
criteria
are
interpreted
by
EPA,
the
States
or
the
Tribes.
And,
finally,
questions
also
have
been
raised
about
whether
or
not
the
criteria
adequately
address
or
apply
to
all
uses
equally.
The
key
to
appropriate
application
of
the
use
removal
criteria
is
to
focus
on
whether
or
not
a
condition,
at
a
specific
site,
would
preclude
attaining
a
designated
use.
A
decision
on
this
question
is
not
always
straightforward
however,
and
as
a
result,
there
are
questions
about
the
application
of
the
use
removal
criteria.
A
few
examples
may
help
the
discussion.
Criterion
number
1
allows
removal
of
a
designated
use
where
``
naturally
occurring
pollutant
concentrations
prevent
attainment
of
the
use.''
A
reoccurring
question
about
this
provision
is:
under
what
circumstances
should
``
naturally
occurring
pollutant
concentrations''
be
the
justification
for
use
removal
versus
the
basis
for
calculating
site­
specific
criteria,
acknowledging
that
the
natural
condition
defines
the
existing
use?
Often,
the
numerical
criteria
assigned
to
the
designated
use
are
the
initial
benchmark
for
estimating
whether
or
not
a
designated
use
will
be
attained.
In
this
approach,
a
comparison
of
the
natural
condition
with
the
numerical
criteria
is
used
in
the
evaluation
of
attainability.
Where
such
an
analysis
demonstrates
clearly
that
the
naturally
occurring
pollutant
concentrations
would
preclude
the
designated
use,
the
use
may
be
removed.
There
are,
however,
examples
of
situations
where
statewide
or
national
criteria
for
one
or
more
contaminants
are
exceeded,
and
yet
the
available
information
on
the
overall
condition
of
the
water
indicate
the
use
is
supported.
This
situation
is
most
common
for
aquatic
life
uses
where
local
populations
of
aquatic
organisms
may
have
acclimated
to
natural
conditions
outside
the
estimated
``
normal''
tolerance
range,
where
species
on
the
edge
of
their
distribution
are
reproducing
but
are
physiologically
stressed
or
where
broadly
derived
criteria
may
not
be
appropriate
for
the
particular
aquatic
community
at
that
site.
In
such
a
situation,
the
observed
condition
of
the
resource
obviously
will
take
precedence
over
the
predicted
condition,
and
the
natural
water
quality
will
form
the
basis
for
site­
specific
criteria
since
the
use
is
clearly
not
precluded.
Again,
the
key
to
answering
the
use
removal
question
is
to
determine
whether
or
not
``
natural
conditions''
preclude
attainment
of
the
use,
and
because
of
the
site­
specific
circumstances
discussed
above,
answering
this
question
involves
more
than
a
simple
comparison
of
numeric
criteria
with
the
natural
condition.
Criterion
number
2
allows
removal
of
a
designated
use
where
natural,
ephemeral,
intermittent,
or
low
flow
conditions
would
preclude
the
use
unless
these
conditions
may
be
compensated
for
by
the
discharge
of
sufficient
volume
of
effluent
discharges
without
violating
State
or
Tribal
water
conservation
requirements
to
enable
uses
to
be
met
(
emphasis
added).
Questions
have
been
raised
about
exactly
what
the
above
italicized
language
means.
EPA's
interpretation
of
this
phrase
is
that,
where
an
effluent
discharge
creates
an
essentially
perennial
flow
for
what
naturally
would
be
ephemeral
or
intermittent
waters,
the
resulting
aquatic
community
is
to
be
protected.
EPA's
current
thinking
is
that
in
situations
such
as
these,
the
second
criterion
for
use
removal
means
that
a
State
or
Tribe
cannot
remove
a
use
of
a
water
body
where
the
augmented
flow
supports
an
aquatic
life
use.
Criterion
number
4
allows
removal
of
a
use
where
dams,
diversions
or
other
types
of
hydrological
modifications
preclude
the
attainment
of
the
use,
and
it
is
not
feasible
to
restore
the
water
body
to
its
original
condition
or
operate
such
modification
in
a
way
that
would
result
in
the
attainment
of
a
use.
As
indicated
above,
some
have
argued
that
operation
of
dams
is
an
inappropriate
basis
for
concluding
that
Section
101(
a)(
2)
uses
are
not
attainable,
and
they
have
suggested
this
criterion
be
removed
from
the
regulation.
In
arguing
this
position,
these
commenters
have
pointed
to
the
1986
amendments
to
the
Federal
Power
Act
(
Electric
Consumer's
Protection
Act,
or
ECPA)
and
the
legislative
history
of
these
amendments
as
an
indication
of
Congress'
intent
to
give
equal
priority
to
protecting
and
restoring
fish
and
wildlife
habitat
even
where
dams
exist.
Specifically,
the
ECPA
states:

*
*
*
In
deciding
whether
to
issue
any
license
the
{
Federal
Energy
Regulatory
Commission
}
,
in
addition
to
the
power
and
development
purposes
for
which
licenses
are
issued,
shall
give
equal
consideration
to
the
purposes
of
energy
conservation,
the
protection,
mitigation
of
damages
to,
and
enhancement
of
fish
and
wildlife
(
including
related
spawning
grounds
and
habitat),
the
protection
of
recreational
opportunities,
and
the
preservation
of
other
aspects
of
environmental
quality.
(
ECPA
amending
the
Federal
Power
Act,
Section
4(
e),
16
U.
S.
C.
Section
797(
e))

The
legislative
history,
these
commenters
believe,
provides
a
particularly
clear
indication
of
congressional
intent
to
protect
and
restore
aquatic
life
uses.
They
specifically
point
to
that
part
of
the
record
which
states
that
no
one
``
expect[
s]
`
business
as
usual,'
''
but
rather
the
expectation
is
that:

[
P]
rojects
licensed
years
earlier
must
undergo
the
scrutiny
of
today's
values
as
provided
in
this
law
and
other
environmental
laws
applicable
to
such
projects.
If
nonpower
values
cannot
be
adequately
protected,
FERC
should
exercise
its
authority
to
restrict
or,
particularly
in
the
case
of
original
licenses,
even
deny
a
license
on
a
waterway.
(
H.
R.
Rep.
No.
99
 
934,
99th
Cong.,
2d
Sess.
(
1986)
at
22)

Groups
arguing
for
removal
of
criterion
4
use
the
amendments
to
the
Federal
Power
Act
as
an
example
of
the
recognition
being
given
today's
environmental
values
and
the
importance
of
restoring
and
enhancing
the
aquatic
habitats
and
recreational
uses
of
water
resources.
They
maintain
that
``...
the
Water
Quality
Rule
should
be
updated
to
recognize
that
aquatic
and
recreational
uses
can
not
be
removed
based
simply
on
the
existence
of
a
dam.''
EPA's
current
thinking
is
that
the
above
rationale
and
legislative
history
raise
a
serious
question
about
whether
the
existence
of
a
dam
and
the
infeasibility
of
operating
that
dam
in
a
way
that
will
result
in
attaining
the
designated
use,
measured
against
today's
values,
is
sufficient
reason
to
remove
a
designated
use.
EPA
is
interested
in
commenters
views
on
this
issue.
Criterion
number
5
allows
removal
of
a
designated
use
where
physical
conditions
related
to
the
natural
features
of
the
water
body,
such
as
the
lack
of
proper
substrate,
cover,
flow,
depth,
pools,
riffles,
and
the
like,
unrelated
to
water
quality,
preclude
attainment
of
36756
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
aquatic
life
protection
uses.
Notwithstanding
the
reference
to
aquatic
life
uses
in
131.10(
g)(
5),
some
have
argued
that
recreational
uses,
especially
swimming
uses,
might
also
be
limited
by
physical
factors
(
especially
where
safety
is
an
issue),
and
they
have
asked
whether
or
not
the
physical
factors
consideration
could
be
applied
to
evaluations
of
recreational
use
attainability.
As
now
written,
the
regulatory
language
would
not
allow
consideration
of
physical
factors,
alone,
as
the
basis
for
removing
a
designated
recreational
use.
In
the
preamble
to
the
1983
regulation,
EPA
explained
that,
while
the
Agency
recognized
that
physical
factors
also
affect
recreational
uses,
States,
and
now
Tribes,
would
need
to
give
consideration
to
incidental
uses
of
the
water
body
even
though
it
may
not
make
sense
to
encourage
use
of
a
stream
for
swimming
because
of
the
flow,
depth
or
velocity
of
the
water.
Instead,
the
preamble
discussion
explained
that
based
on
prudent
public
health
considerations,
the
use
protection
question
was
not
to
be
judged
wholly
on
an
analysis
of
the
water
body's
suitability
for
swimming
but
rather
on
whether
or
not
swimming
would
actually
occur.
EPA's
current
thinking
is
that
physical
factors,
alone,
would
not
be
sufficient
justification
for
removing
or
failing
to
designate
a
primary
contact
recreation
use.
EPA's
suggested
approach
to
the
recreational
use
question
has
been
for
States
and
Tribes
to
look
at
a
suite
of
factors
such
as,
the
actual
use,
existing
water
quality,
water
quality
potential,
access,
recreational
facilities,
location,
safety
considerations,
and
physical
conditions
of
the
water
body
in
making
any
use
attainability
decision.
The
guidance
suggests
that
any
one
of
these
factors,
alone,
may
not
be
sufficient
to
conclude
that
designation
of
the
use
is
not
warranted.
Nevertheless,
there
clearly
are
situations
such
as
high
flows
caused
by
storm
events
where
the
physical
conditions
of
a
water
body
would
make
swimming,
if
not
impossible,
extremely
dangerous.
It
is
in
addressing
situations
such
as
these
that
questions
have
been
raised
about
the
applicability
of
physical
factors
to
the
recreational
use
issue.
The
question
is
sometimes
posed
in
terms
of
whether
or
not
a
State
or
Tribe
would
incur
some
liability
by
designating
or
continuing
to
designate
such
waters
as
swimmable.
They
argue
that
a
reasonable,
common
sense
approach
is
to
acknowledge
that
there
are
certain
waters
for
which
primary
contact
recreation
is
not
an
attainable
use
solely
because
of
the
physical
condition
of
the
water.
EPA
is,
therefore,
considering
whether
the
regulation
or
Agency
guidance
should
be
amended
to
allow
consideration
of
physical
factors,
alone,
as
the
basis
for
removing
or
not
designating
primary
contact
recreational
uses.
The
above
discussion
is
about
EPA's
interpretation
of
the
conditions
that
would
have
to
be
satisfied
to
either
remove
or
not
designate
recreational
uses.
As
explained
earlier
in
this
section,
satisfying
those
conditions
gives
a
State
or
Tribe
the
option
of
either
removing
or
not
designating
the
use.
It
does
not,
however,
create
an
obligation.
A
specific
example
may
help.
A
western
State
was
concerned,
partly
for
liability
reasons,
about
designating
swimming
uses
for
a
number
of
waters
where
the
physical
conditions
and
other
factors
made
swimming,
if
it
did
occur,
unwise.
Although
available
information
indicated
the
actual
swimming
use
was
limited
or
nonexistent,
the
State
also
wanted
to
ensure
protection
of
that
use,
based
on
public
health
considerations,
should
it
occur.
The
issue
for
the
State
was
striking
the
appropriate
balance
between
the
two
concerns:
the
possibility
of
inadvertently
encouraging
swimming
where
it
should
not
occur
because
of
safety
considerations
and
protecting
that
use
if
it
did
occur.
To
resolve
this
issue,
the
State
designated
these
waters
for
secondary
contact
recreation
but
assigned
primary
contact
recreation
bacteriological
criteria
to
provide
an
appropriate
level
of
protection
should
swimming
occur,
however
unlikely.
In
this
way,
the
State
felt
it
did
not
inappropriately
encourage
swimming
in
these
waters,
but
if
swimming
did
occur,
the
required
water
quality
would
provide
an
appropriate
level
of
protection.
This
is
an
approach
to
the
``
incidental
use''
issue,
discussed
in
the
existing
use
section
of
this
chapter,
that,
while
acknowledging
uncertainty,
errs
on
the
side
of
protectiveness.

Consistency
EPA
has
provided
guidance
on
implementing
the
requirements
in
§
131.10(
g).
Although
EPA
believes
the
guidance
has
been
fairly
comprehensive
and
has
functioned
reasonably
well,
the
growing
number
and
recurring
nature
of
the
questions
raised
about
implementation
of
the
use
removal
criteria
have
convinced
EPA
to
solicit
comments
on
the
need
for
additional
guidance
or
regulatory
changes
to
ensure
appropriate
and
consistent
application
of
the
use
removal
criteria.
As
indicated
in
the
introduction
to
this
discussion,
one
of
the
reoccurring
concerns
about
implementation
of
§
§
131.10(
j)
and
131.10(
g)
with
respect
to
designating
or
removing
uses,
is
that
to
some,
there
are
instances
of
inconsistency
in
the
way
the
§
131.10(
g)(
1)
 
(
6)
criteria
are
interpreted
by
EPA,
the
States
or
the
Tribes.
One
example
that
has
been
cited
is
that
the
application
of
the
fish
consumption
use
is
dissimilar
in
different
regions
of
the
country.
In
one
area
of
the
country,
some
maintain,
the
fish
consumption
use
is
applied
to
all
waters
assigned
any
aquatic
life
use
without
regard
to
whether
or
not
there
is
a
credible
exposure
pathway
to
humans
by
way
of
contaminated
fish.
In
other
areas
of
the
country,
the
application
of
the
fish
consumption
use
allows
consideration
of
occurrence,
size
and
species
of
fish
present
and
evidence
that
fishing
actually
occurs
as
a
basis
for
concluding
that
there
is
a
potential
exposure
pathway
and
the
use
should
be
designated.
An
associated
consistency
issue
has
to
do
with
the
manner
in
which
the
terms
in
§
131.10(
g)
are
interpreted.
An
example
is
the
term
``
feasible''
in
criterion
number
4.
Feasibility
could
be
based
on
technical
considerations,
such
as
the
ability
to
operate
an
impoundment
in
an
efficient
manner
that
does
not
degrade
water
quality,
as
EPA
intended
when
it
originally
wrote
the
regulation.
Alternatively,
some
have
suggested
that
feasibility
could
be
based
on
economic
considerations
or
a
balanced
consideration
of
cost
and
technology
(
EPA's
current
thinking
is
that
the
term
``
feasible''
in
use
removal
criterion
number
4,
regarding
the
operation
of
dams
should
continue
to
refer
to
technical
feasibility
and
not
to
economic
feasibility.
Criterion
number
6,
not
number
4,
is
the
appropriate
avenue
to
address
economic
feasibility
of
attaining
the
designated
use
because
it
establishes
an
appropriate
test
of
economic
infeasibleness.)
EPA's
view
is
that
the
use
removal
criteria
should
be
clear
and
consistently
interpreted.
Questions
and/
or
positions
such
as
those
described
above
suggest
there
may
be
a
need
for
additional
guidance
on
or
interpretation
of
§
131.10(
g)
to
ensure
the
§
131.10(
g)
criteria
are
consistently
interpreted
and
applied,
and
to
address
whether
review
under
§
131.10(
g)
could
be
done
for
categories
of
sources.
c.
Use
Attainability
Analysis.
A
use
attainability
analysis
(
UAA)
is
a
structured
scientific
assessment
of
the
factors
affecting
the
attainment
of
uses
specified
in
section
101(
a)(
2)
of
the
Act
(
the
``
fishable/
swimmable''
uses).
The
factors
to
be
considered
in
such
an
analysis
include
the
physical,
chemical,
biological,
and
economic
use
removal
36757
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Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
criteria
described
in
the
current
regulation
(
40
CFR
131.10(
g)(
1)
 
(
6)).
The
current
regulation
(
40
CFR
131.10(
j))
establishes
the
requirement
that
States
and
Tribes
conduct
a
UAA
when
designating
uses
that
do
not
include
the
section
101(
a)(
2)
uses,
removing
section
101(
a)(
2)
uses,
or
designating
new
subcategories
of
section
101(
a)(
2)
uses
that
require
less
stringent
criteria.

New
Information
for
Waters
Without
Section
101(
a)(
2)
Use
Designations
The
current
regulation
(
§
131.20(
a))
specifically
requires
the
re­
examination
of
water
bodies
with
less
than
Section
101(
a)(
2)
use
designations
every
three
years
to
determine
if
new
information
has
become
available.
If
new
information
indicates
that
a
use
is
attainable,
the
State
or
Tribe
is
to
revise
the
use
accordingly.
EPA
interprets
the
current
regulation
as
requiring
review
of
past
UAA­
based
use
designation
decisions
when
there
is
new
information
that
could
have
a
bearing
on
that
use
designation
decision.
The
1983
preamble
to
the
regulation
explained
that
a
State
or
Tribe
need
only
conduct
a
UAA
once
for
a
given
water
body.
The
preamble
went
on
to
explain,
however,
that
where
the
UAA
is
used
as
justification
for
removing
a
section
101(
a)(
2)
use
or
failing
to
designate
a
section
101(
a)(
2)
use,
the
State
is
required
to
review
the
basis
for
that
decision
in
subsequent
triennial
reviews
to
determine
whether
or
not
the
circumstances
have
changed
in
a
way
that
would
alter
the
original
decision.
EPA
recognizes
that
the
requirement
to
review
new
information
about
past
UAA­
based
use
designation
decisions,
because
it
creates
a
demand
for
further
analysis
of
the
decision
by
the
State
or
Tribe,
can
serve
to
discourage
States
and
Tribes
from
generating
new
information.
EPA's
current
thinking
is
that
interested
parties
should
be
encouraged
to
generate
and
consider
relevant
information
that
could
have
a
bearing
on
the
use
designation
decision
for
a
particular
water
and
that
the
trigger
for
reviewing
past
use
designation
decisions
should
be
clear.
In
addition,
EPA
is
interested
in
comments
on
whether
there
should
be
some
definable
burden
placed
on
the
State
or
Tribe
to
actively
seek
information
for
such
waters.
The
Agency
may
need
to
be
more
specific
in
requiring
that
States
and
Tribes
specify
the
procedures
they
will
use
in
identifying
water
bodies
where
``
new
information''
has
become
available
and
ensuring
new
information
is
generated
where
appropriate.
UAAs
and
Non
Section
101(
a)(
2)
Uses
The
current
regulation
indicates
that
the
UAA
requirements
apply
to
uses
specified
in
Section
101(
a)(
2)
of
the
Act.
The
regulation
at
40
CFR
131.10(
j)
specifically
requires
that
a
State
or
Tribe
conduct
a
UAA
where:
``(
1)
the
State
[
or
Tribe]
designates
or
has
designated
uses
that
do
not
include
the
uses
specified
in
Section
101(
a)(
2)
of
the
Act,
or
(
2)
the
State
[
or
Tribe]
wishes
to
remove
a
designated
use
that
is
specified
in
Section
101(
a)(
2)
of
the
Act
or
to
adopt
subcategories
of
uses
specified
in
Section
101(
a)(
2)
of
the
Act
which
require
less
stringent
criteria.''
Although
the
regulation
at
40
CFR
131.10(
g)
has
always
provided
that
States
and
Tribes
may
not
remove
a
designated
use
unless
they
can
demonstrate
that
attaining
the
use
is
not
feasible,
the
regulatory
language
does
not
expressly
require
the
State
or
Tribe
to
conduct
a
UAA
as
defined
in
40
CFR
131.10(
j)
before
a
use
not
referenced
in
section
101(
a)(
2)
may
be
removed.
As
a
result,
some
have
questioned
whether
or
not
the
UAA
requirements
actually
apply
to
uses
other
than
those
referenced
in
Section
101(
a)(
2),
such
as
water
supply
or
agriculture.
EPA's
position
on
this
issue
is
that,
while
the
analysis
to
downgrade
a
use
not
included
in
CWA
section
101(
a)(
2)
is
not
expressly
referenced
in
§
131.10(
j),
40
CFR
131.10(
g)
of
its
own
terms
requires
the
State
or
Tribe
to
document
whether
any
use
being
considered
for
removal
is
attainable
under
the
six
criteria
outlined
in
that
section.
Where
such
a
use
is
shown
to
be
attainable,
it
may
not
be
removed
(
downgraded).
In
practice,
EPA
believes
there
is
no
cognizable
difference
between
these
two
analyses.
EPA
is
thus
considering
whether
it
should
combine
these
elements
of
40
CFR
131.10(
g)
and
131.10(
j)
or
otherwise
clarify
the
relationship
between
these
provisions
in
the
regulation.
Given
EPA's
position
that
the
regulation
requires
the
use
attainability
of
a
water
body
to
be
documented
before
any
of
its
uses
may
be
removed,
EPA
is
interested
in
a
discussion
of
specific
attainability
issues
that
might
arise
in
applying
the
UAA
requirements
to
non­
Section
101(
a)(
2)
uses
such
as
water
supply
or
agriculture.

Information
in
UAAs
The
regulation
is
not
specific
about
what
a
UAA
should
contain
other
than
the
general
description
contained
in
the
definition
of
a
UAA
at
40
CFR
131.3(
g).
Instead,
EPA
has
issued
various
national
and
regional
guidance
documents
to
assist
with
the
completion
of
such
analyses.
Some
have
suggested,
however,
that
the
regulation
be
amended
to
provide
more
specificity
on
information
needed
in
a
UAA.
Topics
for
consideration
might
include:
what
specific
questions
should
a
use
attainability
analysis
address?
what
are
the
data
requirements?
and
what
are
the
requirements
for
reporting
the
results
of
the
analysis?
EPA
seeks
comment
on
this
issue.

UAAs
and
Refinement
of
``
Fishable/
Swimmable''
Use
Designation
As
long
as
a
State
or
Tribe
designates
uses
that
fall
within
the
broad
range
of
uses
consistent
with
the
section
101(
a)(
2)
goals,
there
is
no
requirement
to
conduct
a
UAA.
In
fact,
40
CFR
131.10(
k)
explicitly
states
that
``
a
State
is
not
required
to
conduct
a
use
attainability
analysis
.
.
.
whenever
designating
uses
which
include
those
specified
in
section
101(
a)(
2)
of
the
Act.''
As
a
result,
there
does
not
appear
to
be
a
mechanism
that
ensures
State
or
Tribal
waters
are
not
under­
classified
(
i.
e.,
a
use
subcategory
is
designated
for
a
water
when
a
higher
or
more
protective
subcategory
is
actually
attainable).
Some
have
suggested
that
the
regulation
be
amended
or
guidance
clarified
to
require
a
UAA
(
i.
e.,
a
structured
scientific
assessment)
whenever
an
aquatic
life
use
is
designated
(
or
refined)
to
ensure
the
level
of
protection
assigned
matches
the
potential
for
the
water
body.
EPA's
current
thinking
is
that
there
needs
to
be
a
solid
underlying
rationale
for
use
designations.
One
of
the
emerging
themes
from
EPA
and
the
larger
community
of
parties
interested
in
further
protecting
water
quality
is
that
refining
designated
uses
and
tailoring
suites
of
criteria
to
the
refined
uses
in
watersheds
is
an
important
future
direction
of
this
program.
Clearly
for
this
approach
to
succeed,
a
solid
evaluation
of
attainability
must
be
at
the
heart
of
any
decision
to
characterize
designated
uses
in
greater
detail
than
has
been
the
norm.
EPA
is
interested
in
comment
on
this
view,
in
particular
as
it
relates
to
the
rebuttable
presumption
that
the
generic
uses
described
as
fishable/
swimmable
are
attainable.

Thresholds
for
Aquatic
Life
Use
Designation
In
part
2
of
this
section,
``
Refined
Designated
Uses'',
there
is
a
discussion
explaining
EPA's
position
that
the
definition
of
``
aquatic
life''
is
not
limited
to
those
waters
that
support
``
fisheries.''
That
discussion
explains
that
a
more
biologically­
grounded
definition
of
aquatic
life
would
be
sufficiently
expansive
to
include
aquatic
communities
made
up,
for
example,
36758
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Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
entirely
of
invertebrate
organisms.
This
broad
definition
of
``
aquatic
life
uses''
has
an
impact
on
the
manner
in
which
UAAs
are
planned
and
evaluated.
The
current
regulation
allows
States
and
Tribes
to
designate
uses
for
certain
waters
that
do
not
include
the
section
101(
a)(
2)
uses,
where
such
uses
are
not
attainable.
As
a
result,
some
States
and
Tribes
have
waters
which
have
not
been
assigned
an
aquatic
life
designated
use.
However,
if
aquatic
life
uses
are
defined
broadly,
as
EPA
believes
they
should
be,
there
would
be
very
few,
if
any,
waters
that
would
not
be
considered
as
supporting
some
type
of
existing
aquatic
life
use.
Aquatic
communities
form
a
continuum,
making
it
difficult,
if
not
impossible
in
the
biological
sense,
to
identify
where
the
threshold
for
aquatic
life
use
begins.
As
a
result,
some
have
suggested
that
a
broad
definition
of
aquatic
life
would
appear
to
revoke
the
option
of
excluding
aquatic
life
protection
from
a
water
body
since
essentially
all
waters
support
some
level
of
aquatic
life.
They
have
suggested,
therefore,
that
there
is
a
need
to
identify
a
threshold,
based
on
some
physical
rather
than
biological
limitation,
that
could
be
used
as
an
acceptable
justification
for
concluding
that
an
aquatic
life
use
is
not
attainable.
For
example,
some
States
and
Tribes
have
urged
the
use
of
a
flow­
based
threshold
to
justify
a
conclusion
that
an
aquatic
life
use
in
not
attainable.
Generally,
ephemeral
waters
(
waters
whose
channel
does
not
intersect
the
ground
water
table
and
which
are
dependent
on
precipitation
events
for
their
flow)
are
suggested
as
an
appropriate
threshold.
In
a
biological
sense,
this
may
not
be
a
satisfactory
solution
since
there
are
ecologically
important
ephemeral
waters
which
should
receive
aquatic
life
use
protection
regardless
of
the
temporal
nature
of
the
flow.
This
is
especially
true
for
many
ephemeral
wetlands.
EPA
is
considering
whether
changes
are
needed
in
the
regulation
or
guidance
to
address
whether,
and
under
what
circumstances,
UAAs
may
be
used
to
justify
a
non­
aquatic
life
use
classification,
given
the
broad
range
of
aquatic
communities
that
may
exist.

Request
for
Comments
on
Use
Removal
and
Use
Attainability
EPA
seeks
comment
on
the
following
questions:
1.
Although
EPA
believes
the
use
removal
criteria
in
§
131.10(
g)
have
functioned
reasonably
well,
questions
have
been
raised
about
the
applicability
of
specific
section
131.10(
g)
criteria
and
the
manner
in
which
EPA
interprets
those
criteria.
EPA
seeks
comment
on
the
use
removal
criteria.
Are
the
six
criteria
sufficiently
comprehensive
or
should
other
factors
be
considered
as
a
basis
for
removing
designated
uses?
Are
the
criteria
too
comprehensive
and
are
certain
of
the
criteria
inappropriate
as
a
basis
for
designated
use
removal?
Is
there
a
need
to
modify
the
existing
criteria
to
more
clearly
address
the
full
range
of
use
removal
issues
that
have
developed
since
the
regulation
was
originally
published?
2.
Even
with
the
statements
in
the
current
regulation,
questions
have
been
raised
about
the
minimum
requirements
of
a
use
attainability
analysis.
Is
there
need
for
further
clarification
in
guidance,
policy
or
in
the
regulatory
text
on
this
issue?
3.
Triennial
review
of
UAA­
based
use
designations
that
do
not
include
section
101(
a)(
2)
uses,
are
currently
triggered
only
when
new
information
becomes
available.
Should
EPA
require
that
States
and
Tribes
specify
procedures
they
will
use
in
identifying
what
constitutes
new
information
and
thus
when
the
review
of
the
UAA­
based
use
designations
is
required?
4.
Although
40
CFR
131.10(
g)
requires
an
assessment
of
attainability
before
removal
of
any
designated
use,
the
regulatory
language
does
not
expressly
require
an
analysis
called
a
UAA
as
specified
in
40
CFR
131.10(
j)
any
time
a
State
or
Tribe
seeks
to
designate
a
non
section
101(
a)(
2)
use.
EPA,
however,
believes
that
the
analysis
under
either
provision
is
equivalent.
Should
the
current
regulation
be
revised
to
clarify
that
the
UAA
requirements
apply
to
any
``
downgrade''
of
a
use
and
not
just
the
CWA
Section
101(
a)(
2)
uses?
Can
any
needed
clarification
be
achieved
through
guidance
or
policy?
EPA
would
be
interested
in
comments
on
factors
to
be
considered
in
evaluating
the
attainability
of
non
Section
101(
a)(
2)
uses,
such
as
water
supply
or
agricultural
uses
which
generally
take
place
after
the
water
is
diverted
from
the
natural
water
body.
5.
How
should
the
water
quality
standards
regulation,
guidance
or
policy
be
modified
to
provide
more
specificity
on
appropriate
factors
to
consider
in
developing
a
use
attainability
analysis?
6.
In
order
to
ensure
the
present
aquatic
life
use
designation
(
or
use
subcategory)
matches
the
attainable
level
of
aquatic
life
use
in
a
water
body,
should
the
water
quality
standards
regulation,
policy
or
guidance
be
modified
to
clarify
that
a
periodic
review
of
designated
uses
is
required
where
a
State
or
Tribe
has
designated
only
marginal
or
limited
aquatic
life
uses?
7.
Are
changes
needed
in
the
water
quality
standards
regulation,
policy
or
EPA
guidance
to
address
whether,
and
under
what
circumstances,
use
attainability
analyses
may
be
used
to
justify
a
non­
aquatic
life
use
classification,
given
the
broad
range
of
aquatic
communities
that
may
exist?
d.
Alternatives
to
``
Downgrade''
of
the
Designated
Use.
As
discussed
above,
where
a
State
or
Tribe
believes
that
a
particular
designated
use
is
not
attainable,
States
and
Tribes
have
the
option
of
refining
a
water
body's
designated
use,
for
example
by
creating
subcategories
of
the
use
and
describing
the
use
in
more
detail.
A
subcategory
can,
and
may
need
to
be,
water
bodyspecific
if
the
State's
or
Tribe's
use
classification
system
is
not
sufficiently
precise
to
accommodate
the
subcategory
of
designated
use
for
the
water
body
in
question.
States
and
Tribes
also
have
the
option
of
removing
the
designated
use
and
replacing
the
removed
use
with
a
new
one
that,
under
the
regulation,
reflects
attainable
conditions
in
the
water
body.
Use
removal
and
to
a
lesser
extent
refinement
are
also
commonly
referred
to
as
use
``
downgrade.''
Both
of
these
options,
refinement
and
removal
of
the
designated
use,
are
not
timelimited
That
is,
the
designated
use
that
results
from
exercising
either
of
these
options
becomes
the
new
goal
use
of
the
water
body.
In
the
following
discussion,
three
alternatives
to
use
downgrade
that
have
been
used
by
States
are
presented.
They
are
variances,
temporary
standards,
and
ambient­
based
criteria.
These
alternatives
are
less
``
draconian''
than
use
downgrading
in
the
sense
that
they
can
provide
adjustments
to
particular
aspects
of
the
standards
 
i.
e.,
to
the
criteria
for
particular
pollutants
or
the
criteria
as
applied
to
certain
dischargers
 
without
changing
the
designated
use
and
the
full
suite
of
criteria
to
protect
the
designated
use.
EPA's
current
thinking
is
that
often
the
attainable
condition
of
particular
water
bodies
is
not
well
understood
due
to
uncertainty
about
expected
results
of
water
quality
improvement
actions.
In
such
situations,
EPA
believes
it
may
be
appropriate
to
implement
water
quality
protection
actions,
assess
the
results
of
those
actions,
and
implement
additional
measures
where
necessary
to
continue
to
improve
water
quality.
EPA
believes
that
iterative
assessment
and
implementation
in
these
types
of
situations
is
probably
the
best
way
to
gain
an
understanding
of
the
ultimate
attainable
condition
of
the
water
body.
The
mechanisms
described
below
may
be
well­
suited
to
this
situation
because
they
leave
the
designated
use
of
the
36759
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
water
body,
the
ultimate
goal,
in
place
while
providing
a
defined
period
of
time
(
in
the
case
of
variances
and
temporary
standards)
to
document,
through
implementation
and
assessment,
the
water
quality
improvements
that
are
possible
through
various
measures
and
thus,
the
attainability
of
the
goal.
i.
Variances.
One
option
authorized
under
the
regulation
that
is
used
by
some
States
or
Tribes
is
the
water
quality
standard
variance.
A
variance
is
a
short­
term
exemption
from
meeting
certain
otherwise
applicable
water
quality
standards.
EPA
authorizes
States
and
Tribes
to
include
variances
in
their
water
quality
standards.
(
see
40
CFR
131.13).
Agency
guidance
on
variances
identifies
what
the
Agency
believes
to
be
the
essential
elements
of
a
variance:
 
a
variance
should
be
granted
only
where
there
is
a
demonstration
that
one
of
the
use
removal
factors
(
40
CFR
131.10(
g))
has
been
satisfied;
 
a
variance
is
granted
to
an
individual
discharger
for
a
specific
pollutant(
s)
and
does
not
otherwise
modify
the
standards;
 
a
variance
identifies
and
justifies
the
numerical
criteria
that
will
apply
during
the
existence
of
the
variance;
 
a
variance
is
established
as
close
to
the
underlying
numerical
criteria
as
is
possible;
 
a
variance
is
reviewed
every
three
years,
at
a
minimum,
and
extended
only
where
the
conditions
for
granting
the
variance
still
apply;
 
upon
expiration,
of
the
variance,
the
underlying
numerical
criteria
have
full
regulatory
effect;
 
a
variance
does
not
exempt
the
discharger
from
compliance
with
applicable
technology
or
other
water
quality­
based
limits;
and
 
a
variance
does
not
affect
effluent
limitations
for
other
dischargers.
With
these
safeguards
in
place,
the
principal
difference
between
a
variance
and
a
downgrade
of
a
designated
use
is
that
a
variance
is
temporary.
That
is,
when
the
variance
expires,
an
affirmative
showing
would
be
needed
to
continue
it,
or
the
underlying
standards
are
applicable.
Because
a
variance
is
temporary,
it
actively
supports
the
improved
water
quality
goal,
and
it
can,
under
appropriate
circumstances
serve
as
an
environmentally
preferable
alternative
to
what
otherwise
might
become
a
permanent
change
in
a
designated
use.
Historically,
the
intent
of
the
variance
provision
has
been
to:
provide
a
mechanism
by
which
permits
can
be
written
to
meet
a
modified
standard
where
discharger
compliance
with
the
underlying
water
quality
standard
is
demonstrated
to
be
infeasible
within
the
meaning
of
§
131.10(
g)
at
the
present
time
(
e.
g.,
meeting
the
standard
would
cause
substantial
and
widespread
social
and
economic
impact);
encourage
maintenance
of
original
standards
as
goals
rather
than
removing
uses
that
may
be
ultimately
attainable;
and
ensure
the
highest
level
of
water
quality
achievable
during
the
term
of
the
variance.
EPA
has
approved
State
and
Tribal
use
of
variances
when
the
individual
variance
is
included
in
State
or
Tribal
water
quality
standards,
each
variance
is
subject
to
the
same
public
review
as
other
changes
in
water
quality
standards,
the
State
or
Tribe
demonstrates
that
meeting
the
standard
is
unattainable
based
on
one
or
more
of
the
grounds
listed
in
40
CFR
131.10(
g)
for
removing
a
designated
use,
existing
uses
are
protected,
the
variance
secures
the
highest
level
of
water
quality
attainable
short
of
achieving
the
standard
and
the
State
or
Tribe
demonstrates
that
advanced
treatment
and
alternative
effluent
control
strategies
have
been
considered
(
See
48
FR
51400,
51403
(
Nov.
8,
1983);
Water
Quality
Standards
(
WQS)
Handbook
at
5
 
12;
Memorandum
from
EPA's
Office
of
Water,
``
Variances
in
Water
Quality
Standards,''
March
15,
1985;
and
Decision
of
the
General
Counsel
No.
58,
In
Re
Bethlehem
Steel
Corporation,
March
29,
1977).
The
Preamble
to
the
1983
water
quality
standards
regulation
revision
suggested
that
substantial
and
widespread
social
and
economic
impact,
the
sixth
element
for
use
removal
under
§
131.10(
g),
is
an
important
and
appropriate
test
that,
if
met,
could
be
used
as
the
basis
for
granting
a
variance
(
see
48
FR
51403).
Subsequently,
on
March
15,
1985,
EPA
issued
further
guidance
on
the
conditions
under
which
a
variance
might
be
granted.
The
1985
EPA
Office
of
Water
guidance
explained
that
it
would
be
appropriate
to
grant
shortterm
variances
to
individual
dischargers
based
on
any
of
the
six
factors
for
removing
a
designated
use
as
listed
at
§
131.10(
g).
As
variances
represent
a
temporary
downgrade
in
the
water
quality
standards,
EPA
reasoned
that
more
stringent
treatment
of
variances
than
permanent
downgrades
would
not
be
appropriate.
In
practice,
however,
the
only
factor
that
is
commonly
used
to
grant
a
discharger­
specific
variance
is
the
economic
test.
The
Office
of
Water
guidance
continued
to
interpret
variances
as
being
limited
to
individual
dischargers.
In
``
Guidance
for
State
Implementation
of
Water
Quality
Standards
for
CWA
Section
303(
c)(
2)(
B)''
(
December
1988;
Notice
of
Availability
published
at
54
FR
346,
January
5,
1989),
EPA
recommends
that
States
and
Tribes
adopt
a
variance
provision
whenever
adopting
statewide
or
tribe­
wide
criteria
for
a
large
number
of
toxic
pollutants
for
human
health
or
aquatic
life
protection.
The
rationale
behind
this
recommendation
was
to
avoid
unreasonable
consequences
from
adopting
State­
or
Reservation­
wide
criteria
which
could
underestimate
or
overestimate
the
toxic
potential
of
some
pollutants
in
a
specific
water
body.
The
Water
Quality
Guidance
for
the
Great
Lakes
System
(
Great
Lakes
Guidance)
published
March
1995
by
EPA
(
56
FR
15366,
March
23,
1995;
40
CFR
section
132)
contains
provisions
allowing
for
variances
from
water
quality
standards.
Variances
granted
under
the
Great
Lakes
Guidance
are
pollutant­
specific
and
point
sourcespecific
and
are
limited
to
five
years
or
the
term
of
the
NPDES
permit
implementing
the
variance,
whichever
is
less.
Variances
may
be
granted
for
any
of
the
reasons
listed
at
40
CFR
131.10(
g)
for
which
a
use
downgrade
may
be
considered.
Like
all
revisions
to
State
or
Tribal
water
quality
standards,
EPA
review
and
approval
is
required
of
any
variance
granted
by
a
State
or
Tribe
and
variances
may
be
renewed
following
the
same
procedure
originally
used
for
applying
for
a
variance.
Variances
are
also
subject
to
review
as
part
of
a
State's
or
Tribes
triennial
review
of
water
quality
standards.
Multiple
discharger
variances
(
a
variance
that
applies
to
multiple
point
sources
discharging
to
the
same
water
body)
are
also
allowed
under
the
Great
Lakes
Guidance.
Variances
granted
under
the
Great
Lakes
Guidance
provisions
may
not
jeopardize
the
continued
existence
of
any
Federally
listed
threatened
or
endangered
species.
Further,
under
the
Guidance,
variances
are
not
available
for
new
or
recommencing
discharges.
A
recommencing
discharge
is
a
source
that
recommences
discharge
after
terminating
operations.
(
40
CFR
122.2).
The
Great
Lakes
Guidance
was
developed
in
concert
with
many
other
provisions
addressing
designated
uses,
criteria,
antidegradation
and
various
implementation
policies
for
the
Great
Lakes
States
and
Tribes.
Any
evaluation
of
the
level
of
protection
afforded
water
quality
under
the
Great
Lakes
Guidance
variance
procedures
should
be
made
in
the
context
of
the
Great
Lakes
Guidance
as
a
whole.
Similarly,
the
water
quality
standards
regulation
is
more
than
simply
the
sum
of
its
parts.
Any
36760
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
approach
to
the
implementation
of
water
quality
standards
variances
must
be
evaluated
in
the
context
of
the
entire
regulation.
EPA
is
considering
whether
implementation
of
the
variance
provision
has
been
a
useful
component
of
the
water
quality
standards
program,
and
the
overall
program
for
protection
of
water
quality
standards.
In
1990,
EPA
conducted
a
survey
of
State
variances
and
variance
provisions
(
National
Assessment
of
State
Variance
Procedures,
Report,
November
1990,
Office
of
Water
Regulations
and
Standards).
This
study
showed
that
variances
had
been
granted
on
a
very
limited
basis.
In
fact,
only
16
out
of
57
States
and
Territories
had
granted
variances
and
some
of
those
had
done
so
infrequently.
EPA
lacks
detailed
information
on
why
variances
are
not
being
significantly
utilized
in
most
States
and
Tribes.
EPA
is
interested
in
information
regarding
alternative
mechanisms
that
are
being
used
by
States
or
Tribes
in
lieu
of
variances
to
provide
necessary
short
term
and
temporary
relief
from
applicable
criteria,
and
how
any
alternative
approaches
address
the
feasibility
of
ultimately
attaining
the
criteria
associated
with
the
underlying
designated
use.
EPA
is
considering
whether
it
would
be
useful
to
include
in
the
regulation
more
explicit
language
reflecting
current
EPA
thinking
and
practice
regarding
variances.
As
explained
above,
in
order
to
issue
variances,
States
or
Tribes
must
include
variances
as
part
of
the
State's
or
Tribe's
water
quality
standards.
EPA
believes,
however,
that
in
some
instances
States
may
be
misusing
variances.
For
example,
over
the
years,
there
have
been
instances
where
a
State
has
improperly
granted
a
``
variance''
from
compliance
with
NPDES
permit
limits,
failing
to
include
these
variances
within
the
water
quality
standards
themselves.
There
has
also
been
some
confusion
regarding
the
necessity
of
formal
adoption
of
individual
variances
into
State
and
Tribal
water
quality
standards
and
whether
the
public
participation
process
associated
with
NPDES
permit
issuance
sufficiently
addresses
those
same
needs
for
variance
adoption.
EPA
is
also
considering
whether
to
specify
the
degree
to
which
individual
dischargers
must
document
the
continued
need
for
a
variance
before
the
variance
can
be
renewed
at
each
triennial
review.
EPA
is
considering
whether
the
water
quality
standards
regulation
should
provide
more
specific
guidelines
on
the
use
and
content
of
variance
policies.
EPA's
current
thinking
is
that
the
regulation
may
need
to
articulate
certain
aspects
of
variances
more
explicitly,
including:
 
explicit
reference
to
the
criteria
listed
in
40
CFR
131.10(
g)
as
the
criteria
for
granting
a
variance;
 
explicit
statement
that
the
granting
of
a
variance
may
not
result
in
any
loss
or
impairment
of
an
existing
use;
 
explicit
statement
that
before
a
variance
can
be
granted,
the
applicant
must
provide
documentation
that
treatment
more
advanced
than
that
required
by
sections
303(
c)(
2)(
A)
and
(
B)
of
the
CWA
has
been
carefully
considered,
and
that
alternative
effluent
control
strategies
have
been
evaluated
and
reasonable
progress
is
being
made
toward
meeting
the
underlying
or
original
standards;
 
explicit
statement
requiring
the
highest
level
of
water
quality
achievable
under
the
relaxed,
interim
standard
during
the
period
of
the
variance.
 
explicit
statment
that
a
variance
shall
not
be
granted
if
standards
will
be
attained
by
implementing
costeffective
and
reasonable
best
management
practices
for
nonpoint
source
control.
EPA
believes
that
such
a
clarification
of
its
policy
regarding
variances
could
serve
to
encourage
proper
use
of
variances
by
States
and
Tribes
while
at
the
same
time
reducing
the
possibility
of
inappropriate
use.
ii.
Temporary
Standards.
As
indicated
in
the
discussion
on
variances
above,
the
1985
EPA
Office
of
Water
guidance
explained
that
it
would
be
appropriate
to
grant
short­
term
variances
to
individual
dischargers
based
on
any
of
the
six
factors
for
removing
a
designated
use
as
listed
at
§
131.10(
g).
Of
the
six
use
removal
factors,
the
first
five
address
water
quality
and
habitat
features
of
the
water
body
as
a
whole.
These
same
factors
are
not,
however,
ideally
suited
to
making
decisions
about
the
capabilities
of
individual
dischargers.
For
example,
it
is
not
immediately
clear
how
use
removal
factor
five,
``
physical
conditions
related
to
natural
features
of
a
water
body
*
*
*
preclude
attainment
of
a
use'',
could
be
applied
to
a
decision
about
an
individual
discharger.
On
the
other
hand,
the
sixth
factor,
the
substantial
and
widespread
economic
and
social
impact
factor,
is
well
suited
to
decisions
about
individual
dischargers
which
explains
why
the
economic
hardship
test
has
been
historically
applied
in
evaluating
variances.
Several
States
have
applied
factors
similar
to
the
first
five
use
removal
factors
in
establishing
variances
for
entire
water
body
segments
or
portions
of
water
body
segments.
These
States
sometimes
refer
to
these
as
``
temporary
standards''
or
``
temporary
modifications''.
This
has
been
done
where
the
problems
in
a
water
body
are
significant
and
widespread,
involving
point
and
nonpoint
sources
of
pollution
and
their
impacts
on
water
quality
and
habitat,
that
is
waters
significantly
impaired
by
multiple
sources
and
not
just
one
or
a
few
point
sources.
For
example,
where
historic
mining
practices
have
severely
impaired
both
water
quality
and
habitat
throughout
a
headwater
basin,
temporary
standards
have
been
used.
Rather
than
downgrading
these
waters,
the
States
have
applied
temporary
standards
with
specific
expiration
dates
for
certain
pollutants
affected
by
the
historic
mining
practices.
In
this
way,
the
States
have
maintained
designated
uses
and
underlying
criteria
for
other
pollutants,
while
recognizing
that
existing
ambient
conditions
for
certain
pollutants
are
not
correctable
in
the
short­
term.
In
such
cases,
the
temporary
standards
provide
a
basis
for
permit
limits
in
the
shorterterm
The
temporary
standards
approach
is
then
used
by
these
States
as
the
basis
for
remediation
of
damaged
water
resources
because
the
underlying
designated
use
and
criteria
to
protect
that
use
actively
drive
water
quality
improvements
in
the
longer­
term.
EPA
Regional
Offices
have
approved
the
use
of
such
temporary
standards.
Temporary
standards
have
been
implemented
to
date
with
little
specific
Agency
guidance
on
a
water
body
approach
to
variances.
EPA
is
considering
whether
the
water
quality
standards
regulation
or
guidance
should
specifically
address
temporary
standards.
EPA's
current
thinking
is
that
if
the
regulation
or
Agency
guidance
were
to
specifically
address
temporary
standards,
such
regulation
or
guidance
would
need
to
address
certain
relevant
issues
including:
application
criteria
to
be
used
in
deciding
which
waters
might
qualify
for
temporary
standards;
a
way
of
identifying
the
existing,
impaired
water
quality
conditions;
a
mechanism
for
specifying
the
water
quality
needed
to
fully
attain
the
anticipated
uses;
and
a
plan
and
driving
mechanism
aimed
at
achieving
needed
water
quality
and
habitat
improvements
to
fully
support
compliance
with
the
designated
uses.
Where
EPA
has
provided
guidance
to
individual
States
on
use
of
State
temporary
standards
provisions,
EPA
has
advised
that
any
temporary
standard
should:
 
be
granted
only
where
there
is
a
demonstration
that
one
of
the
use
removal
factors
(
40
CFR
131.10(
g)(
1)
through
(
6)
has
been
satisfied;
36761
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
 
be
granted
for
a
specific
water
body
or
portion
of
a
specific
water
body
as
defined
in
State
standards;
 
identify
and
justify
the
numerical
criteria
that
will
apply
during
the
existence
of
the
temporary
standard
and
identify
a
``
remediation
plan''
aimed
at
compliance
with
the
underlying
designated
uses
and
criteria;
 
be
established
as
close
to
the
underlying
numerical
criteria
as
is
possible;
 
be
reviewed
every
three
years,
at
a
minimum,
and
extended
only
where
the
conditions
for
granting
the
temporary
standard
still
apply;
 
be
in
effect
only
for
the
specified
term
of
the
temporary
standard
(
or
extension
thereof),
and
upon
expiration
of
the
temporary
standard,
the
underlying
numerical
criteria
have
full
regulatory
effect;
 
not
exempt
any
discharge
to
the
water
body
from
compliance
with
applicable
technology
or
water
quality­
based
limits
(
based
on
the
temporary
standards)
or
best
management
practices;
 
not
apply
to
any
new
discharger
to
the
water
body;
and
 
protect
existing
uses.
EPA
is
considering
whether
the
use
of
temporary
standards
represents
a
viable
alternative
to
use
refinement
or
removal.
EPA
is
also
considering
whether
the
regulation
or
guidance
should
explicitly
address
use
of
temporary
standards,
including
specific
limitations
on
the
use
of
temporary
standards
like
those
listed
above.
iii.
Ambient­
based
Criteria.
On
a
limited
basis,
States
have
developed
and
EPA
has
approved
``
ambient­
based
criteria.''
These
ambient­
based
criteria
have
been
developed
for
specific
water
bodies
and
pollutants
where
such
criteria
are
shown
to
protect
the
designated
use
and
the
existing
use.
EPA
believes
that
ambient­
based
criteria
can
be
preferable
to
a
``
downgrade''
of
a
use
because
the
underlying
designated
use
is
retained
and
because
they
may
be
limited
to
only
a
small
subset
of
pollutants.
EPA
has
issued
a
policy
memorandum
concerning
one
type
of
ambient­
based
criteria,
site­
specific
criteria
for
aquatic
life
protection
that
are
based
on
natural
conditions.
(
See
Memorandum
from
Tudor
T.
Davies,
Director
Office
of
Science
and
Technology,
Subject:
Establishing
Site­
Specific
Aquatic
Life
Criteria
Equal
to
Natural
Background,
November
5,
1997.)
This
policy
states
that
States
and
Tribes
may
establish
site­
specific
aquatic
life
criteria
equal
to
natural
background
conditions,
but
such
criteria
must
be
scientifically
defensible.
Additionally,
the
State's
or
Tribe's
water
quality
standards
should
contain
or
provide
specific
authority
for
sitespecific
criteria
based
on
natural
background.
States
and
Tribes
should
also
identify
procedures
for
determining
natural
background.
EPA's
current
policy
also
states
that
the
State
or
Tribal
procedure
for
determining
natural
background
needs
to
be
specific
enough
to
establish
natural
background
concentration
accurately
and
reproducibly.
States
and
Tribes
should
also
provide
for
public
notice
and
comment
on
the
provision,
the
procedure
and
the
site­
specific
application
of
the
procedure.
The
States
or
Tribes
will
also
need
to
document
the
resulting
site­
specific
criteria
in
its
water
quality
standards,
including
specifying
the
water
body
segment
the
site­
specific
criterion
applies
to.
This
can
be
accomplished
through
adopting
the
site­
specific
criteria
into
the
State
and
Tribal
water
quality
standards,
or,
alternatively
by
appending
the
sitespecific
criteria
to
the
water
quality
standards.
In
addition,
a
second
approach
that
some
States
have
used
and
EPA
has
approved
is
where
the
State
or
Tribe
could
have
met
the
test
for
downgrading
a
use
under
40
CFR
131.10(
g)(
3)
i.
e.,
``
Human
caused
conditions
or
sources
of
pollution
prevent
the
attainment
of
the
use
and
cannot
be
remedied
or
would
cause
more
environmental
damage
to
correct
than
to
leave
in
place'',
but
instead
of
downgrading
the
use,
the
State
or
Tribe
established
certain
criteria
based
on
ambient
conditions
where
those
ambient
conditions
were
shown
to
be
irreversible.
In
addition
to
assuring
that
the
existing
use
is
protected,
EPA
is
interested
in
assuring
that
where
the
ambient
concentration
of
a
pollutant
cannot
be
improved,
i.
e.,
it
is
irreversible,
that
such
condition
be
maintained
and
not
made
worse.
When
this
occurs,
EPA
believes
that
for
other
pollutants
in
the
same
water
body
for
which
applicable
criteria
are
being
or
can
be
met,
those
criteria
should
remain
in
place
and
not
be
made
less
protective
via
a
use
downgrade.
EPA's
current
thinking
is
that
the
ambient­
based
criteria
need
to
be
the
best
attainable.
In
addition,
EPA's
current
thinking
is
that
in
order
to
establish
ambient­
based
criteria,
the
State
or
Tribe
should
conduct
an
analysis
equivalent
to
a
use
attainability
analysis
for
a
downgrade
that
should
include
a
thorough
description
of
the
biota
that
will
be
protected
via
applicable
water
quality
criteria
(
both
the
unchanged
preexisting
criteria
and
the
ambient­
based
criteria).
EPA
is
interested
in
hearing
comments
regarding
these
ambientbased
criteria
mechanisms,
and
specifically
whether
the
regulation
should
discuss
these
mechanisms
more
specifically,
and
whether
the
regulation
should
be
more
explicit
about
the
biological
evaluation
necessary
to
describe
the
aquatic
life
use
being
protected.
EPA
is
also
interested
in
comments
on
whether
the
other
relief
mechanisms
based
on
the
§
131.10(
g)
reasons,
such
as
variances
and
temporary
standards,
should
also
require
criteria
which
reflect
the
best
attainable
conditions.

Request
for
Comments
on
Alternatives
to
Downgrading
a
Designated
Use
EPA
seeks
comment
on
the
following
questions:
1.
EPA
requests
comment
on
whether
variances,
temporary
standards
and/
or
ambient­
based
criteria
can
under
certain
circumstances
offer
an
environmentally
preferable
alternative
to
refinement
or
removal
(
downgrade)
of
the
designated
use?
Under
what
circumstances?
2.
Does
the
current
water
quality
standards
regulation
or
Agency
guidance
or
policy
discourage
persons
from
seeking
variances
and/
or
discourage
States
and
Tribes
from
granting
variances
(
including
temporary
standards)?
What
components
of
the
procedures
are
most
problematic?
3.
Reflecting
EPA's
current
interpretation
of
the
regulation,
should
the
regulation
make
explicit
that
individual
variances
and
temporary
standards
must
be
documented
in
a
State's
or
Tribe's
water
quality
standards
before
implementation
as
part
of
NPDES
permits?
4.
Reflecting
EPA's
current
interpretation
of
the
CWA
and
the
regulation,
should
the
regulation
contain
express
reference
to
the
factors
listed
in
40
CFR
131.10(
g)
as
the
criteria
under
which
a
variance
(
including
temporary
standards)
from
water
quality
standards
will
be
allowed?
Should
any
of
these
factors
be
deleted?
Should
any
new
factors
be
added?
5.
Reflecting
EPA's
current
interpretation
of
the
CWA
and
the
regulation
regarding
existing
uses,
should
the
variance
portion
of
the
regulation
at
40
CFR
131.13
underscore
that
the
granting
of
a
variance
must
not
result
in
any
loss
or
impairment
of
an
existing
use,
for
example
by
crossreferencing
the
requirement
at
40
CFR
131.12(
a)(
1)
that
existing
uses
must
be
protected?
6.
To
reflect
current
practice
and
EPA
guidance,
should
the
regulation
be
36762
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
amended
to
require
documentation
by
either
the
applicant
or
the
State
or
Tribe
demonstrating
that
treatment
more
advanced
than
that
required
by
sections
303(
c)(
2)(
A)
and
(
B)
of
the
CWA
has
been
carefully
considered,
and
that
alternative
effluent
control
strategies
have
been
evaluated
and
reasonable
progress
is
being
made
toward
meeting
the
underlying
or
original
standards?
7.
Should
the
regulation
require
that
States
and
Tribes
document
in
their
water
quality
standards
the
criteria
that
are
applicable
to
the
water
body
or
segment
thereof
during
the
period
of
a
variance
or
temporary
standards?
8.
Should
the
regulation
discuss
ambient­
based
criteria
mechanisms
more
specifically?
9.
Should
the
regulation
be
more
explicit
about
the
biological
evaluation
necessary
to
describe
the
aquatic
life
use
being
protected
where
ambient­
based
criteria
are
used?
10.
EPA
is
also
interested
in
comments
on
whether
the
other
relief
mechanisms
based
on
the
§
131.10(
g)
reasons,
such
as
variances
and
temporary
standards,
should
in
the
regulation,
expressly
be
required
to
require
criteria
which
reflect
the
best
attainable
conditions?
11.
Do
the
alternatives
to
use
removal
help
address
pulsed
or
intermittent
impacts,
such
as
those
from
urban
and
rural
runoff?

C.
Criteria
The
following
section
discusses
water
quality
criteria
in
the
water
quality
standards
programs.
EPA
is
considering
the
implementation
of
and
effectiveness
of
different
types
of
criteria
and
on
the
desirability
of
changes
to
the
water
quality
standards
regulation
as
it
pertains
to
criteria.
The
scope
of
the
criteria
section
includes
all
Clean
Water
Act
criteria
for
which
EPA
has
issued
national
criteria
guidance,
and
several
types
of
criteria
for
which
there
is
no
national
criteria
guidance
but
where
criteria
guidance
and
policy
are
being
contemplated.

1.
Background
Water
quality
criteria
are
levels
of
individual
pollutants
or
water
quality
characteristics,
or
descriptions
of
conditions
of
a
water
body
that,
if
met,
will
generally
protect
the
designated
use
of
the
water.
EPA,
under
section
304(
a)
of
the
Act,
periodically
publishes
recommendations
(
guidance)
for
use
by
States
and
Tribes
to
set
water
quality
criteria.
Water
quality
criteria
are
developed
to
protect
aquatic
life
and
human
health,
and
in
some
cases
wildlife,
from
the
deleterious
effects
of
pollutants
and
other
effects
of
pollution.
There
are
three
principal
categories
of
water
quality
criteria:
criteria
to
protect
human
health,
criteria
to
protect
aquatic
life,
and
criteria
to
protect
wildlife.
Within
these
broad
categories,
there
are
different
types
of
criteria,
for
example
within
the
human
health
category,
there
are
chemical­
specific
and
microbiological
criteria.
Within
the
aquatic
life
category,
there
are
chemicalspecific
criteria,
toxicity
criteria,
biological
criteria,
sediment
criteria
and
physical
criteria
such
as
habitat
and
flow
balance.
These
criteria
may
be
expressed
in
either
narrative
or
numeric
forms.
Many
of
these
criteria
may
be
developed
to
apply
generally,
or
they
may
be
developed
to
apply
to
sitespecific
situations.
The
CWA
section
303(
a)
 
(
c)
requires
all
States,
and
any
Tribe
that
has
water
quality
program
authority,
to
evaluate
the
need
for
water
quality
criteria
to
protect
a
designated
use
and
then
adopt
water
quality
criteria
(
either
EPA's
or
its
own)
sufficient
to
protect
uses
designated
for
State
or
Tribal
waters.
Economic
and
technological
factors
(
e.
g.,
the
ability
of
analytical
techniques
to
detect
the
pollutant
and
treatment
cost
considerations)
may
not
be
used
to
justify
adoption
of
criteria
that
do
not
protect
the
designated
use.
Narrative
criteria
are
descriptions
of
conditions
necessary
for
the
water
body
to
attain
its
designated
use.
Often
expressed
as
``
free
from''
certain
characteristics,
narrative
criteria
can
be
the
basis
for
controlling
nuisance
conditions,
e.
g.
floating
debris
or
objectionable
deposits.
Narrative
criteria
are
often
the
basis
for
limiting
toxicity
in
discharges.
States
and
Tribes
establish
narrative
criteria
where
numeric
criteria
cannot
be
established
or
to
supplement
numeric
criteria
under
40
CFR
131.11(
b)(
2).
When
a
water
body
is
classified
for
more
than
one
use,
criteria
necessary
to
protect
the
most
sensitive
use
must
be
applied
to
the
water
body.
40
CFR
131.11(
a).
CWA
section
304(
a)
directs
EPA
to
develop
criteria
guidance.
These
criteria
recommendations
assist
States
and
Tribes
in
developing
water
quality
standards.
The
AWQC
are
published
pursuant
to
Section
304(
a)(
1)
of
the
CWA
which
states:

The
Administrator
*
*
*
shall
develop
and
publish
*
*
*
(
and
from
time
to
time
thereafter
revise)
criteria
for
water
quality
accurately
reflecting
the
latest
scientific
knowledge
(
A)
on
the
kind
and
extent
of
all
identifiable
effects
on
health
and
welfare
including,
but
not
limited
to,
plankton,
fish,
shellfish,
wildlife,
plant
life,
shorelines,
beaches,
esthetics,
and
recreation
which
may
be
expected
from
the
presence
of
pollutants
in
any
body
of
water,
including
ground
water;
(
B)
on
the
concentration
and
dispersal
of
pollutants,
or
their
byproducts,
through
biological,
physical,
and
chemical
processes;
and
(
C)
on
the
effects
of
pollutants
on
the
biological
community
diversity,
productivity,
and
stability,
including
information
on
the
factors
affecting
rates
of
eutrophication
and
rates
of
organic
and
inorganic
sedimentation
for
varying
types
of
receiving
waters.

Pursuant
to
section
304(
a),
EPA
has
developed
to
date,
aquatic
life
criteria
guidance
for
31
chemicals
and
human
health
criteria
guidance
for
100
chemicals.
For
the
most
part,
States
and
Tribes
have
found
such
EPA
criteria
guidance
useful
in
setting
standards
to
protect
designated
uses.
Since
1980,
most
States
and
Tribes
have
adopted
at
least
some
of
the
criteria
guidance
published
by
EPA
pursuant
to
CWA
section
304(
a).
However,
EPA's
resources
available
to
develop
criteria
guidance
are
limited.
Thus,
there
are
cases
where
the
scientific
information
or
data
necessary
to
develop
criteria
exist
but
EPA
has
been
unable
to
establish
section
304(
a)
criteria
guidance.
States
and
Tribes
may
establish
numeric
criteria
using
CWA
section
304(
a)
criteria
guidance,
section
304(
a)
criteria
guidance
modified
to
reflect
site­
specific
conditions,
or
other
scientifically
defensible
methods.
40
CFR
131.11(
b)(
1).
There
are
situations
where
EPA
relies
on
the
304(
a)
criteria
guidance
when
promulgating
replacement
standards
for
a
State
or
Tribe
pursuant
to
section
303(
c).
EPA
promulgation
of
304(
a)
criteria
for
States
or
Tribes
is
discussed
in
more
detail
below.
Numeric
criteria
are
values
expressed
as
levels,
concentrations,
toxicity
units,
or
other
numbers
deemed
necessary
to
protect
designated
uses.
Water
quality
criteria
developed
under
Section
304(
a)
are
based
solely
on
data
and
scientific
judgments
on
the
relationship
between
pollutant
concentrations
and
environmental
and
human
health
effects.
EPA
criteria
under
section
304(
a)
do
not
reflect
consideration
of
economic
impacts
or
the
technological
feasibility
of
meeting
the
chemical
concentrations
in
ambient
water.
As
discussed
below,
304(
a)
criteria
are
used
by
States
and
Tribes
to
establish
water
quality
standards,
and
ultimately
provide
a
basis
for
controlling
discharges
or
releases
of
pollutants.
Numeric
criteria
are
important
because
they
provide
a
proven
effective
basis
for
implementation
of
the
CWA.
For
example,
these
criteria
often
form
the
basis
for
NPDES
water
quality­
based
permit
limits
for
point
source
dischargers
and
for
establishing
TMDLs
for
a
water
body
as
a
whole.
Numeric
criteria
can
also
be
useful
in
assessing
36763
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/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
and
managing
nonpoint
source
pollution
problems.
The
Act
uses
the
term
``
criteria''
in
two
separate
ways.
In
section
303(
c),
the
term
is
part
of
the
definition
of
a
water
quality
standard.
That
is,
a
water
quality
standard
is
comprised
of
designated
uses,
and
the
criteria
necessary
to
protect
those
uses.
Thus,
States
and
Tribes
are
required
to
adopt
regulations
that
contain
legally
enforceable
criteria.
However,
in
section
304(
a)
the
term
``
criteria''
is
used
in
the
scientific
sense.
That
is,
under
section
304(
a),
EPA
develops
scientifically
sound
criteria
guidance
which
may
form
the
basis
for
State,
Tribal
or
Federal
adoption
of
water
quality
standards
pursuant
to
section
303(
c).
Thus,
two
distinct
purposes
are
served
by
the
section
304(
a)
criteria.
The
first
is
as
guidance
to
the
States
and
Tribes
in
the
development
and
adoption
of
water
quality
criteria
that
will
protect
designated
uses,
and
the
second
is
as
the
basis
for
promulgation
of
legally
enforceable
water
quality
criteria
by
the
State
or
Tribe,
or
via
a
superseding
Federal
rule
when
such
action
is
necessary.
As
with
all
science,
new
information
leads
to
new
insights
concerning
pollutant
impacts
on
water
quality.
This
ongoing
evolution
affects
two
important
and
inter­
related
responsibilities
of
the
Agency,
which
are
carried
out
concurrently.
First,
from
time
to
time
EPA
revises
the
304(
a)
water
quality
criteria
to
reflect
the
latest
data
and
advances
in
criteria
science.
EPA
compiles
the
current
water
quality
criteria
guidance
from
time
to
time
in
a
series
of
guidance
documents:
the
Green
Book
in
1968,
the
Blue
Book
in
1972,
the
Red
Book
in
1976,
and
the
Gold
Book
in
1986.
The
second
responsibility
pertains
to
the
requirements
of
section
303(
c).
As
part
of
the
water
quality
standards
triennial
review
process
defined
in
section
303(
c)(
1),
the
States
and
Tribes
are
responsible
for
maintaining
and
revising
water
quality
standards.
Section
303(
c)(
1)
requires
States
and
Tribes
to
review,
and
modify
if
appropriate,
their
water
quality
standards
at
least
once
every
three
years.
If
EPA
determines
that
a
new
or
revised
standard
is
not
consistent
with
the
requirements
of
the
CWA,
or
EPA
determines
that
a
revised
standard
is
necessary
to
meet
the
requirements
of
the
Act,
Section
303(
c)(
4)
authorizes
EPA
to
promulgate
replacement
water
quality
standards.
From
time
to
time
EPA
has
chosen
to
undertake
such
promulgations.
In
doing
so,
EPA
considers
the
most
current
available
scientific
information,
such
as
toxicity
data
and
exposure
assumptions.
With
a
number
of
Federal
promulgations
of
water
quality
criteria
under
section
303(
c)(
4)
occurring
over
time,
or
the
publication
of
a
new
or
revised
304(
a)
criteria
guidance
document,
the
criteria
value(
s)
in
an
earlier
Federal
action
may
differ
from
the
value(
s)
in
a
subsequent
Federal
action.
This
has
led
to
some
confusion
among
the
public
with
regard
to
what
EPA's
current
section
304(
a)
water
quality
criteria
may
be
for
a
given
chemical
at
any
given
time,
and,
what
values
EPA
would
promulgate
for
a
State
or
Tribe
under
section
303(
c).
Currently,
EPA
interprets
the
most
recent
Federal
action,
whether
taken
pursuant
to
303(
c)
or
304(
a),
as
establishing
the
current
section
304(
a)
criteria
guidance.
When
EPA
determines
that
a
Federal
rule
is
necessary
to
correct
deficiencies
in
State
criteria,
EPA
looks
to
the
most
recent
criteria
science,
as
articulated
in
either
section
304(
a)
criteria
guidance
or
EPA's
most
recent
statement
contained
in
a
proposed
or
final
section
303(
c)
rule.
To
date,
the
most
recent
Federal
recalculation
of
section
304(
a)
criteria
occurred
in
the
proposed
California
Toxics
Rule
(
CTR)(
62
FR
42160),
July
30,
1997.
The
proposed
CTR
was
undertaken
pursuant
to
CWA
section
303(
c)(
2)(
B).
In
the
Water
Quality
Act
of
1987,
Congress
increased
the
emphasis
on
numeric
criteria
for
toxic
pollutants
by
enacting
section
303(
c)(
2)(
B).
This
section
requires
all
States
and
any
Tribe
with
water
quality
standards
authority
to
adopt
ambient
water
quality
criteria
for
toxics
(
priority
pollutants)
for
which
EPA
has
published
criteria
under
section
304(
a),
and
for
which
the
discharge
or
presence
could
reasonably
be
expected
to
interfere
with
the
designated
use
adopted
by
the
State
or
Tribe.
In
adopting
such
criteria,
States
and
Tribes
must
establish
numerical
values
based
on:
(
1)
304(
a)
criteria;
(
2)
304(
a)
criteria
modified
to
reflect
sitespecific
conditions;
or,
(
3)
other
scientifically
defensible
methods.
Again,
EPA
views
the
criteria
program
as
constantly
evolving.
Whenever
new
or
revised
criteria
are
published,
whether
under
304(
a)
or
a
rule
under
303(
c),
that
action
establishes
the
Agency's
most
current
section
304(
a)
criteria
guidance.
Whenever
a
State
or
Tribe
revises
its
water
quality
criteria
EPA
compares
the
State
criteria
values
and
the
basis
of
their
derivation
to
the
criteria
contained
in
the
most
recent
Federal
action
(
either
303(
c)(
4)
rule
making
or
304(
a)
criteria
guidance
publication).
Thus,
there
may
be
cases
where
the
applicable
policies
and
science
have
evolved
such
that
EPA
would
be
comparing
State
or
Tribe
adopted
criteria
values
to
Federal
criteria
values
other
than
those
in
older
rules
or
criteria
guidance
to
determine
whether
to
approve
the
State's
or
Tribes's
criteria.
This
approach
is
necessary
to
encourage
State
and
Tribal
adoption
of
the
most
recent
section
304(
a)
criteria.
2.
Ambient
Water
Quality
Criteria
to
Protect
Aquatic
Life
Aquatic
life
criteria
are
scientificallyderived
values,
derived
by
States,
Tribes,
or
EPA,
to
protect
aquatic
life
from
the
deleterious
effects
of
pollutants
in
ambient
water.
States
and
Tribes
may
use
EPA's
section
304(
a)
criteria
guidance
in
developing
such
criteria.
When
developing
numeric
aquatic
life
criteria,
States
and
Tribes
usually
express
two
concentrations;
one
that
protects
against
acute
effects
(
effects
from
short
term
exposure)
and
one
that
protects
against
chronic
effects
(
effects
from
long
term
exposure).
The
shortterm
concentration
is
expressed
as
a
Criterion
Maximum
Concentration
(
CMC)
and
is
the
highest
ambient
concentration
of
a
toxicant
to
which
aquatic
organisms
may
be
exposed
for
a
short
time
period
without
causing
an
unacceptable
effect.
The
long­
term
concentration
is
expressed
as
a
Criterion
Continuous
Concentration
(
CCC)
and
is
the
highest
ambient
concentration
of
a
toxicant
to
which
aquatic
organisms
can
be
continuously
exposed
without
causing
an
unacceptable
effect.
Water
quality
criteria
to
protect
aquatic
life
consist
of
three
components
 
magnitude,
duration
and
frequency.
Magnitude
refers
to
the
acceptable
concentration
of
a
pollutant.
Duration
is
the
period
of
time
(
averaging
period)
over
which
the
ambient
concentration
is
averaged
for
comparison
with
criteria
concentrations.
Frequency
is
how
often
the
criteria
can
be
exceeded
to
allow
the
aquatic
community
sufficient
time
to
recover
from
excursions
of
aquatic
life
criteria
and
to
thrive
after
recovery.
The
numerical
aquatic
life
criteria
are
expressed
as
short­
term
and
long­
term
concentrations
in
order
that
the
criteria
more
accurately
reflect
toxicological
and
practical
realities.
The
combination
of
a
Criterion
Maximum
Concentration
(
CMC),
over
a
one­
hour
acute
duration
(
a
short­
term
average
acute
limit),
and
a
Criterion
Continuous
Concentration
(
CCC),
over
a
four­
day
chronic
duration
(
a
long­
term
average
chronic
limit)
provide
protection
of
aquatic
life
and
its
uses.
Recommended
averaging
periods
are
kept
relatively
short
because
excursions
higher
than
the
average
can
36764
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Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
kill
or
cause
substantial
damage
in
short
periods.
The
frequency
limitations
specify
that
both
the
acute
and
chronic
criteria
may
be
exceeded
once
in
a
three­
year
period
on
the
average.
The
recommended
once
in
a
three­
year
period
coupled
with
the
4­
day
chronic
averaging
period
used
for
the
CCC
approximately
corresponds
to
the
historically
used
criterion
concentrations
that
occurs
in
a
once­
inten
year
seven­
day­
average
low
flow
(
7Q10).
The
once­
in­
three­
year
period
coupled
with
the
one­
hour
acute
averaging
period
used
for
the
CMC
approximately
corresponds
to
the
historically
used
criterion
concentration
that
occurs
in
a
once­
in­
ten
year
oneday
average
low
flow
(
1Q10)
The
method
by
which
EPA
derives
criteria
is
updated
from
time
to
time,
to
incorporate
advances
in
the
science.
To
overcome
the
limitations
in
the
previous
approaches
to
duration
and
frequency,
a
new
risk
assessment
methodology
is
being
developed.
EPA
expects
that
the
new
risk
assessment
methodology
will
include
an
approach
that
will
better
handle
variable
concentrations
by
use
of
a
kinetic­
based
toxicity
model
coupled
with
a
population
response
model.
A
kinetic­
based
toxicity
model
considers
the
speed
at
which
effects
appear
in
different
individuals
and
at
different
concentrations.
The
kinetic­
based
model
allows
prediction
of
the
toxicity
of
any
series
of
time­
variable
concentrations.
It
can
predict
how
often
effects
would
occur,
and
what
fraction
of
individuals
in
the
species
would
be
affected.
To
weigh
the
full
impact
that
a
particular
time
series
of
concentrations
would
have
on
the
exposed
population
of
a
species,
an
additional
factor
is
being
considered:
how
long
it
takes
to
replace
those
individuals
lost
due
to
the
toxic
effects.
Consideration
of
this
involves
the
use
of
a
population
model
indicating
rates
of
recovery
of
different
taxonomic
groups
to
stresses.
The
intent
of
this
part
of
the
derivation
is
to
allow
the
toxic
impact
to
be
portrayed
as
the
overall
average
reduction
in
the
number
of
individuals
in
a
species,
both
during
lethal
or
sublethal
periods
and
during
recovery
periods,
accounting
for
both
partial
lethality
and
partial
recovery.

Request
for
public
comment
on
Aquatic
Life
Criteria
EPA
requests
comments
on
the
following
question:
1.
Prior
to
completion
of
all
of
the
aquatic
life
methodology
revisions,
should
EPA
use
the
tools
that
have
thus
far
been
developed
(
the
kinetic
model
of
individual
organism
response
to
derive
the
appropriate
duration/
averaging
period
of
the
criterion
or
to
evaluate
mixing
zone
alternatives
and
the
population
effects
model
to
derive
the
allowable
frequency
of
excursion
above
the
criterion)
to
re­
examine
and
possibly
revise
its
recommendations
on
the
duration
and
frequency
of
criteria
excursions?

3.
Site­
Specific
Criteria
EPA
also
provides
guidance
on
how
States
and
Tribes
may
develop
sitespecific
numeric
aquatic
life
criteria
that
are
either
more
or
less
stringent
than
the
criteria
adopted
by
the
State
or
Tribe
and
that
would
normally
apply
to
a
water
body.
Currently,
national
guidance
only
has
recommendations
and
methods
for
establishing
sitespecific
water
quality
criteria
for
aquatic
life
but
guidance
is
under
development
for
deriving
site­
specific
sediment
quality
criteria
as
well.
The
regulation
currently
specifies
that
States
and
Tribes
may
adopt
numeric
criteria
based
on
published
CWA
section
304(
a)
guidance,
section
304(
a)
guidance
modified
to
reflect
sitespecific
conditions,
or
other
scientifically
defensible
methods.
40
CFR
131.11(
b).
EPA
recognizes
that
States
and
Tribes
may
want
to
develop
numeric
criteria
that
vary
from
CWA
section
304(
a)
guidance
for
specific
waters
(
e.
g.,
where
chemical
and
physical
characteristics
of
local
waters
alter
the
bioavailability
and/
or
toxicity
of
a
pollutant;
or
when
the
species
or
community
actually
present
or
desired
may
be
more
or
less
sensitive
than
the
species
or
community
represented
by
the
criteria
database.)
In
such
situations,
a
site­
specific
criterion
may
be
appropriate.
EPA
has
developed
and
continues
to
develop
guidance
to
assist
States
and
Tribes
in
the
development
of
site­
specific
criteria.
(
See
Water
Quality
Standards
Handbook,
Second
Edition,
EPA
823
 
B
 
94
 
005a,
August,
1994,
pp
3
 
38
through
3
 
45
and
documents
cited
therein.)
Site­
specific
criteria
are
allowed
by
regulation
and
must
be
submitted
to
EPA
for
review
and
approval,
as
are
any
changes
to
a
WQS.
The
regulation
at
40
CFR
131.11(
b)(
1)
specifically
provides
States
and
authorized
Tribes
with
the
opportunity
to
adopt
water
quality
criteria
that
are
``*
*
*
modified
to
reflect
site
specific
conditions.''
Under
40
CFR
131.5(
a)(
2),
EPA
reviews
State
and
Tribal
standards
to
determine
``
whether
a
State
has
adopted
criteria
to
protect
the
designated
uses''
and
whether
such
criteria
are
scientifically
defensible
(
40
CFR
131.11(
b)).
Existing
guidance
and
practice
are
that
EPA
will
approve
site­
specific
criteria
developed
on
the
basis
of
sound
scientific
rationales.
Currently,
EPA
has
specified
three
scientifically
defensible
procedures
that
States
and
Tribes
may
follow
in
deriving
site­
specific
aquatic
life
criteria.
These
are
the
Recalculation
Procedure,
the
Water­
Effect
Ratio
Procedure
and
the
Resident
Species
Procedure.
These
procedures
can
be
found
in
the
Water
Quality
Standards
Handbook
(
USEPA,
1994).
States
may
also
develop
other
procedures
for
deriving
such
criteria
as
long
as
they
are
scientifically
defensible.
EPA
also
recognizes
there
may
be
naturally
occurring
concentrations
of
pollutants
that
may
exceed
the
national
criteria
guidance
published
under
Section
304(
a)
of
the
Clean
Water
Act.
The
Great
Lakes
Guidance
contains
a
procedure
for
developing
site­
specific
criteria
for
protection
of
wildlife.
While
the
Great
Lakes
States
and
Tribes
must
adopt
a
procedure
consistent
with
that
procedure,
other
States
and
Tribes
may
derive
site­
specific
criteria
using
the
procedure
in
the
Great
Lakes
Guidance
and
such
criteria
can
be
more
or
less
stringent
than
the
applicable
wildlife
criteria
where
scientifically
defensible.
This
is
most
likely
to
be
in
cases
where
a
site­
specific
Bioaccumulation
Factor
(
BAF)
has
been
developed.
The
Great
Lakes
Guidance
also
provides
a
procedure
for
modifying
human
health
criteria
on
a
site­
specific
basis
based
on
differences
in
fish
consumption
or
BAF.
With
regard
to
aquatic
life
criteria,
if
a
State
or
Tribe
could
demonstrate
that
physical
or
hydrological
conditions
preclude
aquatic
life
from
remaining
at
a
site
for
a
period
of
time
in
which
acute
or
chronic
effects
may
occur,
less
stringent
site­
specific
aquatic
life
criteria
are
allowed.
EPA's
current
thinking
is
that
States
and
Tribes
should
identify
in
their
water
quality
standards
the
methods
they
intend
to
use
for
site­
specific
criteria
development
and
generally
the
circumstances
under
which
such
criteria
may
be
developed.
Additional
discussion
and
request
for
comment
on
emerging
rationales
and
methods
for
site­
specific
criteria,
beyond
that
described
and
referenced
above,
is
contained
in
section
B.
4.
d
of
this
notice,
entitled
``
Alternatives
to
Removal
of
the
Designated
Use.''

Request
for
Comments
on
Site­
Specific
Criteria
EPA
seeks
public
comment
on
the
following
questions:
1.
Should
the
regulation
be
modified
to
require
States
and
Tribes
to
specifically
authorize
and
identify
the
procedures
for
developing
site­
specific
water
quality
criteria?
Would
additional
EPA
guidance
be
necessary?
36765
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
2.
Should
the
regulation
or
EPA
guidance
specify
the
circumstances
under
which
site­
specific
criteria
are
necessary?
3.
Does
EPA
need
to
develop
guidance,
policy,
or
clarify
the
regulation
regarding
site­
specific
criteria
based
on
ambient
conditions?
4.
Should
EPA
explore
broadening
the
concept
of
site­
specific
criteria
to
include
watershed­
specific
or
ecosystem­
specific
criteria
perhaps
in
conjunction
with
a
refined
use
designation?
If
so,
what
type
of
additional
guidance
or
policy
is
necessary
to
fully
explain
these
concepts
and
are
any
changes
to
the
regulation
needed
to
enable
and/
or
facilitate
use
of
watershed
or
ecosystemspecific
criteria?

4.
Narrative
Water
Quality
Criteria
Narrative
criteria
can
be
an
effective
tool
for
controlling
the
discharge
of
pollutants
when
numeric
criteria
are
not
available.
Narrative
criteria,
which
have
become
known
as
``
free
froms'',
were
first
developed
in
1968
and
continue
to
be
used
in
State
and
Tribal
water
quality
standards.
EPA
guidance
explains
that
these
``
free
froms''
apply
to
all
waters
of
the
United
States
at
all
flow
conditions
(
including
ephemeral
and
intermittent
streams)
(
see
Water
Quality
Standards
Handbook:
Second
Edition
(
EPA
 
823­
B
 
94
 
006,
August
1994).
Narrative
'
free
from'
criteria
guidance
indicates
that
all
waters
be
free
from
substances,
for
example,
that
(
a)
cause
toxicity
to
aquatic
life
or
human
health,
(
b)
settle
to
form
objectionable
deposits,
(
c)
float
as
debris,
oil,
scum
and
other
materials
in
concentrations
that
form
nuisances,
(
d)
produce
objectionable
color,
odor,
taste
or
turbidity,
or
(
e)
produce
undesirable
aquatic
life
or
result
in
the
dominance
of
nuisance
species.
The
toxic
``
free
froms''
include
protection
from
both
chronic
and
acute
toxicity
and
include
all
pollutants
which
cause
toxic
effects,
including
but
not
limited
to
those
listed
under
Section
307(
a)
if
necessary
to
protect
the
designated
use.
All
States
have
adopted
narrative
water
quality
criteria
pursuant
to
section
303(
c).
See
48
FR
51400
 
51402,
November
8,
1983.
EPA
guidance
interprets
these
``
free
froms,''
as
with
all
criteria,
to
apply
to
the
ambient
water
quality,
not
distinguishing
between
point
sources
and
nonpoint
sources
of
toxicity.
Currently,
40
CFR
131.11(
a)(
2)
of
the
water
quality
standards
regulation
requires
States
and
Tribes
that
have
established
narrative
criteria
for
toxic
pollutants
to
identify
the
methods
by
which
the
State
or
Tribe
intends
to
regulate
point
source
discharges
of
toxic
pollutants
based
on
such
narrative
criteria.
EPA
regulations
at
40
CFR
122.44(
d)(
1)(
v)
and
(
vi)
require
narrative
criteria
to
be
implemented
through
NPDES
permit
limits.
More
specifically,
when
the
permitting
authority
determines
that
a
discharge
causes,
has
the
reasonable
potential
to
cause,
or
contributes
to
an
excursion
above
a
narrative
criterion,
the
permit
must,
under
most
circumstances,
contain
effluent
limits
for
whole
effluent
toxicity.
In
addition,
where
the
permitting
authority
determines
that
a
specific
pollutant
for
which
the
State
or
Tribe
has
not
adopted
a
chemical
criterion
is
in
a
discharge
in
an
amount
that
causes,
has
the
reasonable
potential
to
cause,
or
contributes
to
an
excursion
above
a
narrative
criterion,
the
permit
must
contain
effluent
limits
for
that
pollutant
that
are
based
on
an
interpretation
of
the
State's
or
Tribe's
narrative
criterion.
The
regulation
provides
three
options
for
interpreting
the
narrative
criterion,
and
in
addition,
EPA
has
provided
guidance
on
this
requirement
in
both
the
Technical
Support
Document
for
Water
Quality­
Based
Toxics
Control
and
the
Water
Quality
Standards
Handbook
(
both
Cited
above).
The
guidance
advises
States
and
Tribes
to
develop
implementation
procedures
that
explain
the
application
and
integration
of
all
mechanisms
used
by
the
State
or
Tribe
to
ensure
that
narrative
criteria
are
attained
(
e.
g.,
chemical­
specific
requirements,
whole
effluent
toxicity
requirements,
and
biological
criteria,
where
biological
criteria
programs
have
been
developed
by
the
State
or
Tribe).
The
rationale
for
this
approach
is
that
comprehensive
written
procedures
facilitate
implementation
decisions,
reduce
inconsistencies
that
can
result
in
different
requirements
for
similar
situations,
and
promote
effective
and
sensible
application
of
narrative
toxics
criteria.
Although
all
States
and
Tribes
have
some
type
of
customary
practice
for
implementing
narrative
criteria,
and
many
States
and
Tribes
have
developed
implementation
policies
on
narrowly
defined
topics
(
e.
g.,
to
explain
application
of
whole
effluent
toxicity
testing
requirements),
very
few,
if
any,
States
and
Tribes
have
developed
comprehensive
written
implementation
procedures
that
address
all
of
the
narrative
toxics
criteria
implementation
issues.
The
result
may
be
inconsistent
application
of
narrative
toxics
requirements
within
those
States
and
Tribes
that
have
not
developed
such
procedures.
In
addition,
the
lack
of
documented
methods
makes
it
difficult
for
EPA
to
evaluate
whether
aquatic
life
and
or
human
health
is
being
adequately
protected.

Request
for
Comments
on
Narrative
Criteria
EPA
seeks
public
comment
on
the
following
questions:
1.
Should
the
regulation
require
adoption
of
``
free
froms''
and
similar
criteria
as
being
the
minimum
floor
allowable
under
the
Clean
Water
Act.
2.
Reflecting
current
practice,
should
the
regulation
specify
that
States
and
Tribes
are
required
to
adopt
narrative
criteria
for
all
waters?
3.
At
this
time,
EPA
has
limited
information
about
how
States
and
Tribes
are
implementing
narrative
criteria
with
regard
to
nonpoint
source
activities.
How
can
narrative
criteria
best
be
implemented
in
the
nonpoint
source
context
and
what
might
EPA
do,
including
modifying
the
regulation,
to
enhance
or
further
the
use
of
narrative
criteria?
4.
Does
the
existing
requirement
for
States
and
Tribes
to
identify
methods
for
implementing
narrative
toxics
criteria
need
to
be
clarified,
and
if
so,
should
EPA
clarify
the
requirement
with
additional
guidance,
or
with
revisions
to
the
regulation?
5.
What
minimum
elements
should
be
included
in
an
implementation
method
for
narrative
toxics
criteria?
Should
implementation
methods
describe
application
and
integration
of
all
of
the
various
mechanisms
used
to
regulate
point
sources,
or
should
such
methods
focus
on
only
certain
aspects
of
toxics
control
(
e.
g.,
chemical­
specific
limits,
whole
effluent
toxicity
limits)?
6.
The
current
regulation
requires
the
State
or
Tribe
to
identify
the
method
by
which
the
State
or
Tribe
intends
to
regulate
point
source
discharges
of
toxic
pollutants
on
water
quality
limited
segments
based
on
such
narrative
criteria.
Should
this
narrative
criteria
translation
method
apply
only
to
point
source
discharges
of
toxic
pollutants
on
water
quality
limited
segments
or
to
both
point
and
non­
point
sources?
7.
Should
the
regulation
more
explicitly
require
implementation
procedures
for
narrative
criteria
other
than
toxics
criteria?
Should
the
regulation
include
minimum
requirements
for
these
implementation
procedures?

5.
State
or
Tribe
Derived
Criteria
States
and
Tribes
may
develop
their
own
criteria
although
the
water
quality
standards
regulation
40
CFR
131.11
provides
that
where
such
criteria
are
less
stringent
than
304(
a)
criteria
36766
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
guidance,
the
State
or
Tribe
must
demonstrate
the
criteria
are
scientifically
defensible.
Despite
this
available
flexibility,
and
for
a
variety
of
reasons,
most
States
and
Tribes
are
reluctant
to
derive
their
own
criteria.
EPA
is
evaluating
whether
either
changes
to
the
water
quality
standards
regulation
or
development
of
additional
guidance
would
assist
State
or
Tribal
efforts
to
develop
protective
criteria.
For
example,
for
many
pollutants
where
EPA
criteria
guidance
has
not
been
issued,
information
is
available
which
would
be
useful
in
determining
a
protective
water
quality
criterion.
Sources
of
such
information
include
relevant
scientific
literature,
EPA's
Integrated
Risk
Information
System
(
IRIS),
EPA's
Aquatic
Toxicity
Database
(
AQUIRE),
a
database
of
high
quality
aquatic
life
toxicity
data
(
under
development),
and
other
sources.

Request
for
Comment
on
State
or
Tribal
Derived
Criteria
EPA
requests
comment
on
the
following
question:
1.
Would
changes
to
the
water
quality
standards
regulation
or
development
of
additional
guidance
assist
State
or
Tribal
efforts
to
derive
criteria?
What
changes
or
guidance
would
be
most
helpful?

6.
Water
Quality
Criteria
for
Priority
Pollutants
EPA
has
not
revised
the
water
quality
standards
regulation
to
incorporate
CWA
section
303(
c)(
2)(
B)
which
was
added
to
the
CWA
in
1987.
EPA
has,
however,
issued
guidance
on
how
States
and
Tribes
may
comply
with
section
303(
c)(
2)(
B).
The
``
Guidance
for
State
Implementation
of
Water
Quality
Standards
for
CWA
Section
303(
c)(
2)(
B):
December,
1988''
provides
three
options
for
compliance:

Option
1
States
and
Tribes
may
adopt
Statewide
or
Reservation­
wide
numeric
chemical­
specific
criteria
for
all
priority
toxic
pollutants
where
EPA
has
issued
CWA
section
304(
a)
criteria
guidance.
Option
2
States
and
Tribes
may
adopt
numeric
chemical­
specific
criteria
for
those
stream
segments
where
the
State
or
Tribe
determines
that
the
priority
toxic
pollutants
for
which
EPA
has
issued
CWA
section
304(
a)
criteria
guidance
are
present
and
can
reasonably
be
expected
to
interfere
with
designated
uses.
Option
3
States
or
Tribes
may
adopt
a
chemical­
specific
translator
procedure
that
can
be
used
to
develop
numeric
criteria
as
needed.

The
phrase
``
translator
procedure''
in
this
context
means
a
method
for
translating
a
State's
or
Tribe's
narrative
toxics
criterion
into
chemical­
specific,
numeric
criteria
sufficient
to
comply
with
CWA
section
303(
c)(
2)(
B).
As
discussed
in
EPA
guidance
(``
Guidance
for
State
Implementation
of
Water
Quality
Standards
for
CWA
Section
303(
c)(
2)(
B),''
December
1988,
Notice
of
Availability
at
54
FR
346,
January
5,
1989),
such
translator
procedures
generally
identify
the
equations,
protocols,
and
data
sources
that
are
used
to
translate
narrative
criteria
into
derived
chemical­
specific
criteria.
Such
translator
procedures
are
different
from
the
narrative
criteria
implementation
procedures
required
in
40
CFR
131.11(
a)(
2)
of
the
water
quality
standards
regulation
in
that
such
implementation
procedures
must
be
adopted
into
the
State's
or
Tribe's
regulations
and
generally
describe
all
mechanisms
that
are
used
and
integrated
to
attain
narrative
criteria,
including
chemical­
specific,
whole
effluent
toxicity,
and
biological
methods
(
see
the
discussion
of
narrative
criteria
implementation
procedures
in
subsection
(
c)(
6)
above).
EPA
believes
that
revisions
to
the
water
quality
standards
regulation
to
incorporate
the
CWA
section
303(
c)(
2)(
B)
requirements
would
enhance
public
understanding
of
EPA's
implementation
of
the
provision.
EPA's
guidance
on
CWA
section
303(
c)(
2)(
B)
established
a
presumption
that
any
information
indicating
that
such
pollutants
are
discharged
or
present
in
surface
waters
(
now
or
in
the
future)
may
be
considered
sufficient
justification
to
require
adoption
or
derivation
of
numeric
criteria.
The
guidance
made
clear
that
the
requirement
to
adopt
(
or
derive)
criteria
applies
not
just
to
pollutants
that
are
already
affecting
surface
waters,
but
also
to
pollutants
that
have
the
potential
to
affect
surface
waters
in
the
future.
The
rationale
for
this
approach
is
that
it
is
important
to
have
numeric
criteria
applied
to
waters
where
current
or
future
activities
may
result
in
sources
of
priority
toxics
that
warrant
regulatory
controls
or
other
pollution
abatement
or
assessment
activities.
This
interpretation
of
section
303(
c)(
2)(
B)
is
now
reflected
in
EPA
guidance
included
in
the
Technical
Support
Document
(
TSD)
for
Water
Quality­
Based
Toxics
Control
(
TSD)
and
the
Water
Quality
Standards
Handbook
(
see
page
30
in
the
TSD).
In
implementing
CWA
section
303(
c)(
2)(
B),
many
States
and
Tribes
have
adopted
statewide
or
reservationwide
criteria
for
all
priority
toxics
where
EPA
has
issued
CWA
section
304(
a)
criteria
guidance.
Taking
this
approach
eliminates
the
need
to
determine
whether
a
``
reasonable
expectation''
for
use
interference
exists
on
a
water
body­
by­
water
body
basis,
and
thus
greatly
simplifies
the
process
for
establishing
numeric
criteria
for
priority
toxics.
In
other
States
and
Tribes,
however,
broad
application
of
numeric
criteria
for
priority
toxics
has
not
occurred,
and
the
``
reasonable
expectation''
question
has
been
a
significant
implementation
issue.
EPA
is
considering
whether
its
existing
guidance
on
this
issue
is
adequate
to
support
equitable
decisions
nationally.
Another
issue
stemming
from
CWA
section
303(
c)(
2)(
B)
implementation
concerns
the
State
or
Tribe
option
to
develop
a
``
translator
procedure''
to
achieve
compliance.
In
EPA's
CWA
section
303(
c)(
2)(
B)
guidance,
this
approach
was
described
as
Option
3.
The
guidance
intended
to
be
used
are
the
1980
Human
Health
Guidelines
and
1985
Aquatic
Life
Guidelines.
All
of
which
have
been
both
peer
reviewed
and
publicly
reviewed
and
thus
meet
the
requirements
of
``
scientific
defensibility''
under
40
CFR
131.11.
Although
EPA
believes
that
adoption
of
such
chemical­
specific
translator
procedures
potentially
provide
a
State
or
Tribe
with
a
useful
means
of
establishing
criteria,
there
are
several
issues
associated
with
the
use
of
such
procedures.
For
example:
(
1)
It
may
be
difficult
for
the
public
to
stay
abreast
of
the
current
applicable
criteria
where
a
State
or
Tribe
does
not
routinely
publish
an
updated
list
of
State
or
Tribe
criteria
and
provide
wide
distribution.
(
2)
Public
participation
may
occur
primarily
on
the
details
of
the
procedure
itself,
rather
than
the
pollutant­
specific
criteria
resulting
from
application
of
the
procedure.
(
3)
Without
requirements
to
submit
to
EPA
for
review
and
approval
the
individual
criteria
generated
using
the
translator
procedure,
there
could
be
a
tendency
to
not
include
such
criteria
in
the
State's
or
Tribe's
water
quality
standards
at
the
time
they
are
generated.
A
third
issue
that
arises
from
State
and
Tribal
efforts
to
implement
CWA
section
303(
c)(
2)(
B)
concerns
the
provision
for
priority
toxic
pollutants
that
are
not
the
subject
of
CWA
section
304(
a)
criteria
guidance.
Where
such
numeric
criteria
guidance
is
not
available,
and
where
necessary
to
protect
the
designated
uses,
CWA
section
303(
c)(
2)(
B)
provides
that
when
a
State
or
Tribe
(
1)
reviews
Water
Quality
Standards
or
(
2)
revises
or
adopts
new
standards
pursuant
to
this
paragraph,
States
and
Tribes
are
to
adopt
criteria
based
on
biological
monitoring
or
assessment
methods.
When
adopting
criteria
based
on
biological
monitoring
or
assessment
methods,
States
and
Tribes
currently
36767
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
have
considerable
latitude
to
devise
an
approach
to
satisfy
the
requirement.
For
example,
States
and
Tribes
may
establish
ambient
criteria
for
the
parameter
toxicity.
Alternatively,
States
and
Tribes
could
adopt
narrative
biological
criteria.
Clearly,
a
variety
of
approaches,
representing
a
range
of
resource
commitments,
may
be
used
to
satisfy
this
requirement.
All
of
these
approaches
must
meet
the
test
of
``
scientific
defensibility''
and
be
consistent
with
the
goals
of
the
CWA.

Request
for
Comments
on
Water
Quality
Criteria
for
Priority
Pollutants
EPA
seeks
public
comment
on
the
following
questions:
1.
With
regard
to
compliance
with
section
CWA
section
303(
c)(
2)(
B),
would
it
be
better
to
include
only
a
general
requirement,
such
as
one
which
repeats
the
language
in
the
statute
itself,
or
should
the
regulation
reflect
EPA's
interpretation
of
the
options
to
achieve
compliance
with
the
provision?
2.
Have
problems
or
issues
arisen
in
the
implementation
of
CWA
section
303(
c)(
2)(
B)
that
may
need
to
be
addressed
by
changes
in
the
regulation
or
revised
EPA
guidance?
3.
What
factors
should
be
considered
in
determining
whether
a
``
reasonable
expectation''
for
use
interference
exists?
How
has
the
``
reasonable
expectation''
threshold
decision
been
interpreted
and
addressed
by
the
States
or
Tribes?
Does
EPA
need
to
clarify
when
a
``
reasonable
expectation''
for
use
interference
exists,
and
if
so,
should
the
Agency
clarify
the
requirement
by
issuing
additional
guidance,
by
issuing
regulatory
requirements,
or
a
combination
of
the
two
approaches?
4.
Where
a
State
or
Tribe
adopts
a
chemical­
specific
translator
procedure
for
derivation
of
numeric
criteria,
what
process
should
the
State
or
Tribe
follow
to
ensure
that
notice
of
State
derived
criteria
is
provided
to
the
public?
5.
Should
EPA
require
States
or
Tribes
using
translator
procedures
to
publish
an
updated
list
of
criteria
for
all
water
bodies?
6.
Should
EPA
revise
the
regulation
to
explicitly
require
that,
where
a
translator
procedure
is
used
to
derive
criteria,
public
participation
is
required
for
each
individual
criterion,
even
where
an
opportunity
for
public
participation
was
previously
provided
when
the
procedure
itself
was
adopted?
7.
Should
submission
of
each
criterion
derived
using
translator
mechanisms
for
review
and
approval
or
disapproval
be
a
requirement,
even
where
EPA
previously
reviewed
and
approved
the
procedure
itself?
If
so,
should
implementation
of
derived
criteria
(
e.
g.,
in
NPDES
permit
renewal
and
development)
proceed
even
where
EPA
has
not
yet
issued
an
approval/
disapproval
decision?
8.
Does
this
statutory
provision
need
to
be
further
clarified
and
interpreted
by
the
Agency?
Should
changes
to
the
water
quality
standards
regulation
or
Agency
guidance
be
pursued?

7.
Criteria
for
Non­
Priority
Pollutants
with
Toxic
Effects
Over
the
years,
an
issue
which
has
periodically
arisen,
particularly
for
nonpriority
pollutants,
has
been
the
proper
approach
to
identifying
the
circumstances
for
which
adoption
of
numeric
criteria
is
required.
Currently,
the
regulation
does
not
elaborate
on
how
this
question
should
be
addressed;
it
only
provides
the
general
mandate
to
adopt
criteria
``
sufficient
to
protect
uses.''
EPA's
current
thinking
is
that
the
regulation
should
probably
be
modified
to
further
specify
the
circumstances
under
which
numeric
criteria
for
nonpriority
pollutants
must
be
adopted.
One
approach
would
be
to
model
the
requirements
for
non­
priority
pollutants
after
the
requirements
included
in
CWA
section
303(
c)(
2)(
B)
for
priority
pollutants.
That
is,
for
non­
priority
pollutants
where
EPA
has
issued
criteria
guidance,
the
regulation
could
require
adoption
of
numeric
chemical­
specific
criteria
where
the
discharge
or
presence
of
the
pollutant
can
reasonably
be
expected
to
interfere
with
designated
uses.
EPA
could
define
``
reasonable
expectation''
broadly
to
support
adoption
of
criteria
before
new
pollution
sources
are
proposed,
or
more
narrowly
for
non­
priority
pollutants,
limiting
such
a
requirement
for
adoption
of
criteria
to
only
those
water
bodies
and
pollutants
where
uses
are
already
being
interfered
with,
or
where
pollution
sources
now
exist
or
are
certain
to
occur
in
the
near
future.
Establishing
Such
a
requirement
would
encourage
development
of
criteria
for
commonly­
discharged
and
highly
toxic
pollutants
like
ammonia
and
chlorine
that
are
currently
not
considered
priority
pollutants
under
section
307(
a)
of
the
CWA.
Strengthening
the
requirements
for
adoption
of
criteria
for
non­
priority
pollutants
would
address
a
concern
of
some
that
many
of
the
CWA
section
307(
a)
priority
pollutants
are
no
longer
an
appropriate
focal
point
for
State,
Tribe
and
EPA
toxic
control
efforts
(
e.
g.,
some
of
the
pesticides
included
on
that
list
are
no
longer
in
widespread
use).
Request
for
Comments
on
Criteria
for
Non­
Priority
Pollutants
With
Toxic
Effects
EPA
seeks
public
comment
on
the
following
questions:
1.
For
what
specific
pollutants
and
under
what
circumstances
should
adoption
of
criteria
for
non­
priority
pollutants
be
required
by
regulation?
2.
Should
EPA
amend
the
water
quality
standards
regulation
or
issue
additional
guidance
to
clarify
when
adoption
of
numeric
chemical­
specific
criteria
for
non
priority
pollutants
is
necessary
to
``
protect
designated
uses''?
3.
Should
EPA
require
States
or
Tribes
to
adopt
narrative
criteria
and
a
narrative
criteria
translation
method
for
both
307(
a)
and
other
pollutants
which
elicit
toxic
effects
on
organisms?

8.
Criteria
Where
Data
or
Guidance
is
Limited
A
key
issue
facing
States
and
Tribes
seeking
to
develop
aquatic
life
and
human
health
criteria
concerns
the
data
requirements
necessary
to
support
derivation
of
a
criterion.
(
In
developing
national
CWA
section
304(
a)
criteria
guidance,
EPA
has
established
minimum
data
requirements.)
When
sufficient,
acceptable
data
are
not
available,
however,
many
States
and
Tribes
have
resorted
to
adoption
of
lowest
observed
effect
levels
(
LOELs)
as
criteria
in
order
to
ensure
that
some
level
of
protection
is
in
place.
LOELs
are
based
on
the
lowest
observed
concentration
of
a
chemical
at
which
a
statistically
significant
adverse
effect
was
observed
in
an
aquatic
test
organism.
However,
EPA
would
counsel
against
adoption
of
water
quality
criteria
based
on
LOELs
alone
because
they
may
not
ensure
protection
of
aquatic
life
uses
since:
(
1)
they
represent
effect
concentrations,
and
(
2)
there
may
be
significant
limitations
in
the
database
upon
which
they
are
supported.
Thus,
if
this
approach
is
used,
States
and
Tribes
are
encouraged
to
use
safety
factors
to
approximate
better
a
protective
water
quality
level.
The
particular
safety
factor
employed
generally
depends
on
the
amount
and
quality
of
data
concerning
the
LOEL.
EPA
has
approved
this
approach
in
particular
instances
because
criteria
based
on
such
LOELs
provide
more
protection
than
no
criteria
at
all.
A
better
approach
to
developing
values
with
sparse
data
was
developed
and
promulgated
by
EPA
as
part
of
the
Water
Quality
Guidance
for
the
Great
Lakes
System
(
Great
Lakes
Guidance).
Under
that
Guidance's
Tier
II
procedure,
States
and
Tribes
derive
values
to
interpret
the
narrative
criteria
for
36768
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
pollutants
where
the
minimum
data
requirements
for
derivation
of
a
criterion
are
not
satisfied
(
see
appendix
C
of
40
CFR
Part
132.)
These
values
are
then
used
in
place
of
the
absent
criteria
as
the
basis
for
NPDES
permit
limits
where
needed.
EPA's
current
thinking
is
that
this
approach
for
establishing
values
for
interpreting
the
narrative
for
pollutants
where
data
are
limited
is
preferable
to
adoption
of
criteria
based
on
a
LOEL.
The
Tier
II
methodology
in
the
Great
Lakes
Guidance
is
designed
to
be
used
in
the
absence
of
the
full
set
of
data
needed
to
meet
criteria
data
requirements.
For
pollutants
for
which
criteria
have
not
been
adopted
into
State
or
Tribal
water
quality
standards,
Great
Lakes
States
must,
under
the
guidance,
use
methodologies
consistent
with
either
the
criteria
(
GLI
Tier
I)
or
Tier
II
methodologies,
depending
on
the
data
available
to
implement
their
existing
narrative
water
quality
criteria
that
prohibit
toxic
pollutants
in
toxic
amounts
in
all
waters.
In
adopting
the
Great
Lakes
Tier
II
methodology,
EPA,
working
with
the
States,
determined
that
there
is
a
need
to
regulate
pollutants
more
consistently
in
the
Great
Lakes
System
when
faced
with
limited
data
on
which
to
base
criteria.
Many
of
the
Great
Lakes
States
are
already
employing
procedures
similar
to
the
approach
in
the
final
Guidance
to
implement
narrative
criteria.
EPA
determined
the
Tier
II
approach
improves
upon
existing
mechanisms
by
utilizing
all
available
data.
The
Tier
II
aquatic
life
methodology
is
used
to
derive
Tier
II
values
which
can
be
calculated
with
fewer
toxicity
data
than
under
the
Tier
I
water
quality
criteria
methodology.
Tier
II
values
can,
in
certain
instances,
be
based
on
toxicity
data
from
a
single
taxonomic
family,
provided
the
data
are
acceptable.
The
Tier
II
methodology
generally
produces
more
stringent
values
than
the
Tier
I
criteria
methodology,
to
reflect
greater
uncertainty
in
the
absence
of
additional
toxicity
data.
As
more
data
become
available,
the
derived
Tier
II
values
tend
to
become
less
conservative.
That
is,
they
more
closely
approximate
Tier
I
numeric
criteria.
States
and
Tribes
may
also
develop
their
own
criteria
derivation
procedure
under
option
3
of
EPA's
CWA
section
303(
c)(
2)(
B)
guidance
for
priority
toxic
pollutants.
This
approach
allows
for
timely
derivation
of
criteria
based
on
the
latest
available
data,
and
may
be
used
to
derive
criteria
for
pollutants
for
which
EPA
has
not
issued
guidance.
However,
as
for
all
criteria,
such
a
procedure
would
need
to
result
in
criteria
that
are
scientifically
defensible,
so
again
the
issue
of
minimum
data
requirements
is
important.

Request
for
Comment
on
Criteria
Where
Data
or
Guidance
is
Limited
EPA
requests
comment
on
the
following
questions:
1.
Should
adoption
of
a
lowest
observed
effect
concentration
be
considered
an
acceptable
option
where
no
other
criteria
guidance
is
available,
or
should
use
of
an
uncertainty
factor
(
e.
g.,
0.1,
0.5)
be
required
to
better
approximate
a
protective
water
quality
level?
If
an
uncertainty
factor
is
used,
should
that
factor
vary
based
on
the
amount
and
quality
of
data
used
to
drive
the
LOEL?
If
so
how?
2.
Should
EPA
develop
a
method
for
derivation
of
alternative
values
for
pollutants
where
the
minimum
data
requirements
included
in
EPA's
criteria
guidelines
are
not
satisfied,
such
as
the
tier
2
procedure
in
EPA's
Water
Quality
Guidance
for
the
Great
Lakes
System?
3.
How
applicable
should
the
Tier
2
process
be
to
States
and
Tribes
outside
of
the
Great
Lakes?
Does
the
regulation
need
to
be
modified
to
include
Tier
2
specifically
for
the
entire
country?
4.
Does
the
information
included
in
EPA's
toxicity
databases
(
e.
g.,
IRIS,
AQUIRE)
need
to
be
made
more
accessible
to
States,
Tribes,
or
others
seeking
to
develop
their
own
criteria?
If
so,
how
can
this
be
accomplished?

9.
Toxicity
Criteria
Toxicity
criteria
are
an
additional
type
of
water
quality
criteria
used
to
protect
aquatic
life.
Toxicity
criteria
are
expressed
in
terms
of
``
toxic
units''
that
cause
toxic
effects
to
aquatic
organisms
and
are
determined
by
exposing
aquatic
organisms
to
water
samples
(
e.
g.,
ambient
water
or
effluent
discharges).
Whole
effluent
toxicity
(
WET)
testing
can
be
effective
for
controlling
discharges
containing
multiple
pollutants.
It
can
also
provide
a
method
for
addressing
synergistic
and
antagonistic
effects
on
aquatic
life.
EPA
is
considering
revising
the
water
quality
standards
regulation
to
require
States
and
Tribes
with
water
quality
standards
authority
to
develop
a
numeric
quantification
of
acceptable
surface
water
levels
for
the
parameter
``
toxicity.''
Doing
so
would
implement
the
narrative
criteria
that
waters
be
``
free
from''
toxics
in
toxic
amounts.
Currently,
States
and
Tribes
use
various
approaches
to
implementing
their
narrative
criteria,
including
using
numeric
toxicity
values
and
implementing
them
through
NPDES
permits.
However,
there
is
no
current
requirement
for
States
or
Tribes
to
specify
numeric
criteria
for
toxicity
in
their
water
quality
standards.
Under
current
requirements
and
guidance,
States
and
Tribes
do
not
always
specify
implementation
of
toxicity
criteria
and
test
methods
as
a
required
means
to
implement
the
narrative
water
quality
criteria.
Toxicity
is
commonly
measured
by
exposing
test
organisms
(
e.
g.
Ceriodaphnia,
Fathead
minnow)
to
various
concentrations
of
chemicals
or
chemical
mixtures
in
water.
EPA
has
promulgated
methods
for
measuring
aquatic
toxicity
in
effluents
and
surface
waters
in
40
CFR
Part
136.
EPA
provided
a
recommendation
on
the
allowable
magnitude
of
this
parameter
in
the
1991
Technical
Support
Document
for
Water
Quality­
based
Toxics
Control
(
TSD)
that
would
facilitate
State
or
Tribal
implementation
of
such
a
requirement.
The
recommendation
reads:
For
protection
against
acute
toxicity,
``
the
criterion
maximum
concentration
(
CMC)
should
not
exceed
0.3
acute
toxic
units
to
the
most
sensitive
of
at
least
3
test
species;
for
chronic
protection,
the
criterion
continuous
concentration
(
CCC)
should
not
exceed
1.0
chronic
toxic
units
to
the
most
sensitive
of
at
least
3
test
species.''
Such
a
quantification
serves,
in
conjunction
with
numeric
criteria
for
individual
pollutants
and
biological
criteria,
to
establish
an
integrated
and
fully
protective
basis
for
assessment
and
control
of
pollutants.

Request
for
Comment
on
Toxicity
Criteria
EPA
seeks
public
comment
on
the
following
question:
1.
Should
the
regulation
be
modified
to
explicitly
require
States
and
Tribes
to
adopt
numeric
toxicity
criteria,
or
alternatively
to
use
toxicity
values
and
test
methods
as
a
required
means
to
interpret
and
implement
the
narrative
criteria?
Or,
is
the
current
practice
acceptable,
whereby
some
States
or
Tribes
have
numeric
toxicity
criteria,
some
utilize
toxicity
methods
to
interpret
their
narrative
requirements
of
no
toxics
in
toxic
amounts,
and
others
use
toxicity
mainly
as
a
tool
to
assess
effluent
quality,
but
not
as
the
basis
for
permit
limits?

10.
Sediment
Quality
Criteria
Sediment
quality
criteria
(
SQC)
are
being
developed
by
EPA
pursuant
to
sections
304(
a)(
1)
and
118(
c)(
7)(
C)
of
the
CWA
in
recognition
that
many
water
bodies
are
not
meeting
water
quality
goals
even
though
ambient
water
quality
criteria
are
being
met.
(
See
``
The
Incidence
and
Severity
of
Sediment
Contamination
in
Surface
Waters
of
the
36769
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
United
States,
Volume
1:
National
Sediment
Inventory,''
Office
of
Science
and
Technology,
September
1997,
EPA
 
823
 
R
 
97
 
006.)
The
contaminants
of
interest
are
those
that
preferentially
partition
to
sediments,
become
sequestered,
and
remain
bioavailable
to
the
aquatic
community.
SQC
are
intended
to
protect
against
chronic
effects
to
benthic
organisms
resulting
from
sediment
contamination.
The
development
and
implementation
of
SQC
is
intended
primarily
to
enable
development
of
pollutant­
specific
State
standards
and
NPDES
permit
limits
needed
for
implementation
of
a
more
effective
source
control
program.
In
addition,
SQC
will
be
useful
in
other
programs,
such
as
developing
clean­
up
levels
for
sediment
remediation
activities
and
in
evaluating
sediments
dredged
from
the
Nation's
waterways.
Sediment
quality
criteria
have
been
proposed
for
five
non­
ionic
organic
compounds:
acenapthene,
dieldrin,
endrin,
fluoranthene,
and
phenanthrene.
See,
Technical
Basis
for
Deriving
Sediment
Quality
Criteria
for
Nonionic
Organic
Contaminants
for
the
Protection
of
Benthic
Organisms
by
Using
Equilibrium
Partitioning
(
EPA
 
822
 
R
 
93
 
011);
Acenapthene
(
EPA
 
822
 
R
 
93
 
013);
Dieldrin
(
EPA
 
822
 
R
 
93
 
015);
Endrin
(
EPA
 
822
 
R
 
93
 
016);
Fluoranthene
(
EPA
 
822
 
R
 
93
 
012);
Phenanthrene
(
EPA
 
822
 
R
 
93
 
014).
In
addition
to
non­
ionic
organic
compounds,
the
Agency
also
is
working
to
develop
SQC
for
metals.
After
considering
public
comments,
EPA
intends
to
publish
final
SQC
dieldrin
and
aldrin
in
final
form.
The
proposed
criteria
for
acenapthene,
fluoranthene,
and
phenanthrene
will
not
go
final;
instead,
EPA
plans
to
propose
a
total
PAH
sediment
criterion.
In
addition
to
its
work
on
SQC,
the
Agency
also
is
working
to
develop
standardized
methods
for
performing
chronic
sediment
bioassay
tests.
The
EPA
Science
Advisory
Board
subcommittee
reviewing
SQC
for
nonionic
organics
concluded
that:
``
these
criteria
not
be
used
as
stand­
alone,
passfail
values
for
all
applications.''
(
EPA
 
SAB
 
EPEC
 
93
 
002).
EPA
is
developing
a
users
manual
to
provide
guidance
on
use
of
SQC
in
a
regulatory
context
to
ensure
consistency
with
that
recommendation.
The
guidance
would
recommend
that
SQC
be
used
in
conjunction
with
chronic
sediment
bioassay
tests
in
determining
compliance
with
State
standards,
such
as
in
interpreting
the
narrative
criterion
of
no
toxics
in
toxic
amounts.
Such
an
approach
is
currently
being
developed
in
more
detail,
and
the
users
guidance
will
be
made
available
to
the
public
for
comment
prior
to
being
finalized.

Request
for
Comment
on
Sediment
Quality
Criteria
EPA
seeks
public
comment
on
the
following
questions:
1.
Should
the
current
regulation
be
revised
to
specifically
address
sediment
quality
criteria,
and
if
so,
what
should
such
revisions
address?
2.
What
chemicals
or
classes
of
compounds
should
receive
priority
for
development
of
SQC?

11.
Biological
Criteria
Biological
Integrity,
Assessments
and
Criteria
'

The
Clean
Water
Act
directs
EPA
to
work
with
States
and
Tribes
to
restore
and
maintain
the
biological
integrity
of
the
Nation's
surface
waters
(
CWA
101(
a),
303,
518(
e)).
Biological
integrity
is
defined
as
a
balanced,
integrated,
adaptive
community
of
organisms
having
a
species
composition,
diversity,
and
functional
organization
comparable
to
that
of
the
natural
habitat
of
a
region
(
Karr
and
Dudley,
EPA
 
440/
5
 
90
 
004,
1981).
Biological
integrity
does
not
necessarily
represent
an
aquatic
system
untouched
by
human
influence,
but
does
represent
one
that
is
balanced,
adaptive
and
reflects
natural
evolutionary
processes.
Designated
uses
and
criteria
to
protect
those
uses
in
State
and
Tribal
water
quality
standards
programs
provide
the
means
to
achieve
biological
integrity.
To
more
fully
protect
aquatic
resources
and
provide
more
comprehensive
assessments
of
aquatic
life
use
attainment,
it
is
EPA's
policy
that
States
and
Tribes
should
designate
aquatic
life
uses
for
their
waters
that
appropriately
address
biological
integrity
and
adopt
biological
criteria
necessary
to
protect
those
uses
(
EPA
 
823
 
B
 
93
 
002,
Office
of
Water
Memorandum
to
EPA
Regions,
Policy
on
Bioassessment
and
Biological
Criteria,
1991).
Designated
uses
to
support
aquatic
life
can
cover
a
broad
range,
or
continuum,
of
biological
conditions
with
some
waters
being
closer
to
the
ideal
of
biological
integrity
than
others.
The
attainable
levels
of
biological
integrity
for
any
water
is
a
State
and/
or
Tribal
determination
involving
public
participation.
For
example,
the
State
of
Maine
used
the
water
quality
classification
law
to
establish
the
minimum
standards
for
three
levels
of
biological
integrity.
These
levels
correspond
to
the
water
quality
classification
system
and
are
increasingly
restrictive,
proceeding
from
the
minimum
state
standard,
Class
C,
to
Class
A,
the
most
protective
standard.
These
refinements
serve
to
explicitly
specify
the
designated
aquatic
life
uses
that
apply
to
each
classification
category.
Class
C
requires
that
the
structure
and
function
of
the
biological
community
be
maintained
and
provides
for
the
support
of
all
indigenous
fish
species.
The
intermediate
standard
of
Class
B
requires
that
there
be
no
detrimental
changes
to
the
aquatic
community,
that
all
indigenous
species
are
supported
and
that
habitat
be
unimpaired.
The
Class
A
standard
requires
that
aquatic
life
be
``
as
naturally
occurs''
and
habitat
be
characterized
as
``
natural.''
Within
Class
A,
there
is
even
a
subset,
Class
AA,
that
further
specifies
``
free­
flowing''
habitat.
Waters
with
the
Class
AA
designation
are
protected
from
any
additional
discharge
or
alteration.
Under
this
system,
attainment
of
the
aquatic
life
classification
standards
for
a
given
water
body
is
evaluated
using
numeric
biological
criteria
that
were
statistically
derived
from
a
statewide
database.
The
numeric
biological
criteria
are
slated
to
go
to
rule­
making
in
1998.
Biological
assessments
are
used
to
evaluate
the
condition
of
a
water
body
using
direct
measurements
of
the
resident
biota
in
surface
waters.
Biological
assessments
integrate
the
cumulative
impacts
of
chemical,
physical,
and
biological
stressors
on
aquatic
life.
Biological
criteria,
derived
from
biological
assessment
information,
can
be
used
to
define
State
and
Tribal
water
quality
goals
for
aquatic
life
by
directly
characterizing
the
desired
biological
condition
for
an
aquatic
life
use
designation.
Biological
criteria
are
narrative
descriptions
or
numerical
values
that
describe
the
reference
condition
of
the
aquatic
biota
inhabiting
waters
of
a
specific
designated
aquatic
life
use
(
EPA
 
440/
5
 
90
 
004).
Biological
criteria
are
based
on
integrated
measures,
or
indices,
of
the
composition,
diversity,
and
functional
organization
of
a
reference
aquatic
community.
The
reference
condition
describes
the
attainable
biological
conditions
for
water
body
segments
with
common
characteristics
within
the
same
biogeographic
region.
In
summary,
biological
criteria
provide
a
direct
measure
of
the
desired
condition
of
the
aquatic
biota.
This
capability
serves
a
dual
purpose
 
goal
setting
and
environmental
impact
analysis.
Biological
assessments
are
then
conducted
to
evaluate
if
a
water
body
is
attaining
its
designated
aquatic
life
use.
Biological
criteria
can
play
an
important
role
in
water
quality
programs
and
when
properly
implemented,
complement
and
support
36770
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
other
methods
and
criteria,
such
as
chemical
water
quality
criteria
and
whole
effluent
toxicity
criteria.
The
latter
are
measures,
or
indicators,
of
environmental
stress
and
exposure
whereas
the
biological
assessments
and
criteria
measure
the
cumulative
effects
of
stressors
on
the
aquatic
community,
whether
chemical,
physical
or
biological
stressors,
singly
or
in
combination.
A
water
quality
program
that
employs
the
full
array
of
methods
and
criteria
will
develop
the
information
needed
for
more
accurate
assessment
of
impairment
and
effective
resource
management.
The
linkage
of
biological
effects,
stressor
identification
and
exposure
assessment
is
particularly
important
when
there
are
multiple
stressors
impacting
a
water
body,
especially
when
a
watershed
management
approach
is
taken,
or
where
wet
weather
flows
are
a
major
source
of
impairment
in
the
water
body.
A
comprehensive
water
quality
program
with
biological,
chemical,
toxicity,
and
physical
components
will
enable
States
and
Tribes
to
make
better
decisions
and
focus
limited
resources
to
maximize
environmental
gain.
A
critical
issue
facing
EPA's
National
Water
Program
is
the
manner
and
extent
to
which
biological
assessments
and
criteria
should
be
incorporated
into
water
quality
programs
to
transition
to
a
more
comprehensive
water
quality
control
program
that
will
better
identify
impairments
and
track
improvements.
This
includes
integrating
biological
assessments
and
criteria
into
use
designations
and
attainability
analyses,
watershed
management
strategies
and
source
control
requirements.
Biological
criteria
typically
include
measures
of
the
types,
abundance,
and
condition
of
aquatic
plants
and
animals,
providing
information
on
the
status
and
function
of
the
aquatic
community
in
response
to
the
cumulative
impact
of
both
chemical
and
nonchemical
stressors.
For
example,
Ohio
uses
a
multi
metric
approach
to
develop
numeric
biological
criteria
for
two
different
assemblages:
benthic
macro
invertebrates
(
bottom
dwelling
insects,
etc.)
and
fish
(
Yoder,
1995).
Biological
indices
have
been
derived
that
integrate
measurable
structural
and
functional
characteristics
of
the
in­
stream
fish
and
macro
invertebrate
communities
which
help
assess
the
health
of
the
community.
Structural
characteristics
are
based
on
measures
of
biological
community
structure
such
as
diversity
or
taxa
richness
(
e.
g.
total
number
of
taxonomic
groups)
and
the
representation
of
specific
taxonomic
groups
(
e.
g.
number
of
mayfly
or
caddisfly
taxonomic
groups)
within
the
community.
Functional
characteristics
include
measures
of
biological
function
such
as
feeding
strategy
(
e.
g.
percent
carnivores,
omnivores),
environmental
tolerance
(
e.
g.
number
of
intolerant
and
tolerant
species),
and
disease
symptoms
(
e.
g.
percent
diseased
species
and
anomalies,
including
deformities,
eroded
fins,
lesions
and
external
tumors
in
fish).
The
Ohio
biological
criteria
were
developed
based
on
ecoregional
reference
conditions
and
provide
a
quantitative
biological
description
of
the
State's
designated
aquatic
life
uses
for
warm
water
rivers
and
streams,
including
exceptional,
general,
modified
and
limited
warm
water
habitat.
The
description
and
derivation
of
the
indices
and
ecoregions
are
contained
in
the
``
Biological
Criteria
for
the
Protection
of
Aquatic
Life:
Volume
II.
Users
Manual
for
Biological
Field
Assessment
of
Ohio
Surface
Waters''
cited
in
Ohio's
Water
Quality
Standards.
Ohio
uses
biological
criteria
to
support
all
aspects
of
its
water
quality
management
program
(
Yoder,
1995).
Ohio's
approach
is
another
example
of
how
a
State
can
adopt
biologicallybased
refined
designated
aquatic
life
uses
and
biological
criteria
consistent
with
EPA's
policy.

Application
of
Biological
Assessments
and
Criteria
in
State
and
Tribal
Water
Programs
Biological
assessments
and
criteria
can
be
an
important
component
of
State
and
Tribal
watershed
management
programs
by
assisting
in
prioritization
and
targeting
of
actions,
setting
restoration
goals
and
performance
standards,
and
documenting
results.
For
example,
North
Carolina
has
adopted
narrative
biological
criteria
into
its
water
quality
standards
regulation
that
references
standardized
methods
for
data
collection
and
analysis
for
fish
and
macro
invertebrate
communities.
Specific
biological
indices,
metrics,
or
numeric
criteria
are
not
included
in
the
water
quality
standards
regulation.
However,
by
citing
the
standardized
methods
in
the
State's
water
quality
standards,
North
Carolina
established
a
mechanism
for
consistent,
quantitative
translation
of
the
narrative
biological
criteria.
Under
the
State's
five
year
basin­
wide
management
program,
benthic
macro
invertebrate
and
fish
community
data
are
presented
in
individual
basin­
wide
assessment
reports.
Macroinvertebrate
and
fish
community
surveys,
special
studies,
and
other
water
quality
sampling
activities
are
conducted
in
the
second
and
third
years
of
the
cycle
to
provide
information
for
assessing
status
and
trends
through
the
basin.
Water
quality
management
plans
are
being
developed
for
all
of
the
State's
major
river
basins
on
five
year
cycles.
Biological
assessments
and
criteria
can
fulfill
several
assessment
functions
within
the
NPDES
permitting
process.
In
conjunction
with
pollutant
concentration
and
toxicity
data,
biological
assessments
can
be
used
to
detect
previously
undetected
chemical
water
quality
problems
and
to
evaluate
the
effectiveness
of
control
actions.
Biological
findings
of
use
impairment
can
trigger
the
necessary
technical
investigations
which
can
identify
the
source
or
sources
of
impairment
and
determine
appropriate
corrective
measures
through
point
or
nonpoint
source
controls
as
appropriate.
The
State
of
Maine
uses
biological
assessments
and
criteria
to
evaluate
the
effectiveness
of
controls
and
to
inform
the
permit
review
process.
Aquatic
life
criteria
are
specified
in
the
water
quality
classification
law
and
attainment
is
assessed
using
quantitative
data
and
a
multi
variate
statistical
model.
Findings
of
biological
impairment
trigger
management
intervention
to
identify
possible
causes.
Permits
have
been
modified
and
enforcement
actions
initiated
to
address
biological
impacts.
Alternatively,
favorable
biological
findings
have
been
used
in
a
tiered
approach
to
re­
direct
limited
agency
and
permittee
resources
to
more
urgent
concerns.
In
Maryland,
investigators
use
bioassessments
as
an
integral
part
of
the
Rapid
Stream
Assessment
Technique
(
RSAT)
to
conduct
watershed­
wide
stream
quality
reconnaissance,
rapid
screening
of
general
storm
water
BMP
performance
and
for
elucidating
general
watershed
land
use
 
stream
quality
relationships
(
Galli,
J.,
1997).
In
Michigan,
biological
assessments
have
been
used
in
the
Wayne
County
Rouge
River
National
Wet
Weather
Demonstration
Project
to
identify
impacts
and
to
guide
decision­
makers
and
the
public
in
evaluating
options
for
preventing,
reducing
and
minimizing
pollution
loading
impacts
on
the
river
under
a
watershed
approach
to
wet
weather
pollution
management
(
Cave,
1997).
Biological
assessments
and
criteria
can
be
useful
in
evaluating
highly
variable
or
diffuse
sources
of
pollution
such
as
storm
water
runoff.
These
types
of
point
source
pollution
do
not
lend
themselves
well
to
traditional
chemical
water
quality
monitoring
and
a
biological
assessment
of
their
cumulative
impact
may
effectively
evaluate
these
discharges
and
the
success
of
control
actions.
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/
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7,
1998
/
Proposed
Rules
Bioassessments
have
been
successfully
used
in
Florida
to
assess
the
cumulative
impacts
of
multiple
pollution
sources
within
a
watershed,
in
particular,
storm
water
runoff
and
other
nonpoint
source
discharges
(
McCarron,
Livingston
and
Frydenborg,
1997).
The
Florida
Storm
water/
Nonpoint
Source
Bioassessment
Projects
have
found
that
bioassessments,
over
time,
help
reflect
impacts
from
the
fluctuating
environmental
conditions
and
highly
variable
pollutant
inputs
of
wet
weather
discharges.
Bioassessments
also
help
to
evaluate
the
habitat
degradation
typically
associated
with
Storm
water
discharges.
Bioassessments
were
also
identified
by
key
storm
water
experts
from
across
the
Nation
as
an
important
environmental
indicator
tool
for
assessing
the
impacts
of
storm
water
runoff
and
the
effectiveness
of
storm
water
management
strategies
(
Claytor
and
Brown,
1996).
When
attempting
to
identify
the
specific
sources
of
use
impairment
(
stressors),
the
role
that
biological
assessments
and
criteria
will
play
needs
to
be
carefully
defined.
Stressor
identifications
based
solely
on
biological
information
may
be
straightforward
in
certain
water
bodies
where
a
single
source
is
the
cause
of
impairment.
In
these
cases,
paired
bioassessments,
conducted
above
and
below
the
discharge
point,
or
in
the
vicinity
of
the
source,
may
readily
identify
the
degree
of
impairment
and
the
efficacy
of
chosen
control
strategies.
In
small
urban
watersheds,
dominated
by
storm
water
runoff,
bioassessments
and
criteria
may
provide
a
direct
means
to
measure
and
control
the
storm
water
impacts.
However,
in
complex
water
bodies,
where
numerous
sources
contribute
to
the
observed
biological
impairment,
it
may
be
difficult
for
bioassessments
to
distinguish
the
relative
degrees
of
impairment
from
each
contributing
source.
Given
these
situations,
EPA
anticipates
that
a
stressor
identification
evaluation
(
SIE)
procedure
will
need
to
be
developed
to
provide
the
technical
tools
and
information
that
watershed
managers
can
use
to
identify
and
evaluate
the
different
sources
of
impairment
that
the
bioassessments
reveal
and
the
specific
stressors
associated
with
each
source
(
e.
g.
flow,
turbidity,
temperature,
metals,
etc.).

Guidance
on
Development
of
Biological
Criteria
EPA
has
developed
and
will
continue
to
develop
technical
guidance
on
conducting
bioassessments
and
developing
biological
criteria
for
the
following
specific
water
body
types:
streams
and
wadable
rivers,
lakes
and
reservoirs,
estuaries
and
near
coastal
waters,
wetlands
and
large
rivers.
Technical
guidance
for
streams
and
small
rivers
biological
assessments
and
criteria
was
published
in
1996
(
EPA
822
 
B
 
96
 
001).
Publication
of
technical
guidance
on
lakes
and
reservoirs
is
expected
in
1998
followed
by
guidance
on
estuaries
and
near
coastal
waters
by
1999.
Technical
guidance
development
for
wetlands
was
initiated
in
1997
and
for
large
rivers
in
1998.
Completion
of
these
documents
is
planned
within
5
years.

Guidance
on
Implementation
of
Biological
Criteria
EPA
is
currently
considering
how
to
best
advance
State
and
Tribal
adoption
and
implementation
of
biological
criteria.
A
draft
discussion
document
on
implementation
of
biological
criteria
by
States
and
Tribes
sets
forth
an
iterative,
step­
wise
approach
to
development
of
biological
criteria
and
adoption
in
State
and
Tribal
water
quality
standards.
(
draft
guidance
document
on
biological
criteria
implementation,
EPA,
March
1998)
Elements
of
a
stepwise
approach
could
include:
(
1)
establishment
of
a
long
term
goal
to
restore
and
maintain
biological
integrity
of
State
or
Tribal
surface
waters
where
determined
feasible;
(
2)
implementation
plan
for
development
of
biological
criteria
for
specific
water
body
types,
including
time
frame;
(
3)
development
of
standardized
biological
assessment
methods,
regional
reference
conditions,
and
biological
database
to
support
refinement
of
designated
aquatic
life
uses
and
development
of
biological
criteria;
(
4)
adoption
of
narrative
biological
criteria
into
water
quality
standards;
(
5)
adoption
of
quantitatively­
based
biological
criteria
in
water
quality
standards.
In
developing
a
flexible,
stepwise
approach,
EPA
is
evaluating
options
for
adoption
of
biological
criteria
that
would
result
in
the
consistent
translation
of
narrative
biological
criteria
into
numeric
criteria
(
e.
g.
quantitatively­
based
biological
criteria).
A
quantitatively­
based
biological
criteria
could
be
defined
as:
(
1)
A
narrative
statement
adopted
into
State
or
Tribal
water
quality
standards
that
describes
specific
designated
aquatic
life
uses
and
cites
technical
procedures
existing
outside
of
regulation.
The
technical
procedures
result
in
the
translation
of
the
narrative
statement
into
quantitative
measures;
including
description
of
how
biological
assessment
data
is
collected
and
analyzed,
and
how
the
biological
criteria
are
developed.

 
and/
or
 
(
2)
A
narrative
statement
as
above
plus
the
adoption
of
the
technical
procedures
or
the
actual
numeric
biological
criteria
in
State
or
Tribal
water
quality
standards.
These
two
options
for
adopting
quantitatively­
based
biological
criteria
are
based
on
existing
State
models
such
as
Maine,
North
Carolina
and
Ohio
(
EPA
230
 
R
 
96
 
007).
North
Carolina
has
adopted
a
narrative
biological
criteria
for
its
aquatic
life
use
classification
and
cites
in
the
water
quality
standard
regulation
the
standardized
methods
for
data
collection
and
analysis.
Maine
and
Ohio
have
developed
more
refined
classifications
of
their
aquatic
life
uses
and
developed
biological
criteria
for
each
specific
use.
Both
States
cite
technical
manuals
specifying
standardized
methods.
Ohio
has
adopted
its
numeric
biological
criteria
directly
into
its
standards
regulation.
As
mentioned
earlier,
the
Maine
Department
of
Environmental
Protection
is
currently
embarking
on
a
rule
making
process
to
adopt
its
existing
standardized
field
methods,
statistical
analysis
protocols
and
numeric
classification
criterion
(
numeric
biological
criteria)
into
its
water
quality
regulation.
Similar
to
Ohio,
these
rules
will
codify
the
technical
procedures
for
determining
attainment
of
aquatic
life
use
classification.
EPA
describes
these
various
States'
work
for
consideration
as
possible
models
of
biological
criteria
that
would
result
in
the
consistent
translation
of
narrative
biological
criteria
into
numeric
criteria
(
e.
g.
quantitatively­
based
biological
criteria).

A
Regulatory
Requirement
for
Biological
Criteria
EPA
is
considering
whether
it
should
explicitly
require
States
and
Tribes
to
adopt
biological
criteria
in
either
the
narrative
or
numeric
form,
and,
if
not,
whether
an
alternative
approach
to
encouraging
the
use
of
biological
criteria
is
appropriate.
Some
States
and
Tribes
have
already
allocated
resources
to
biological
criteria
development
because
a
regulatory
requirement
is
anticipated
at
some
time
in
the
future.
Others
have
been
unwilling
to
commit
resources
to
development
of
biological
criteria
before
specifically
required
to
do
so.
Concerns
have
also
been
raised
about
yet
another
regulatory
requirement
to
be
imposed
over
existing
requirements
that
are
still
not
fully
implemented
 
adding
new
layers
of
requirements
in
a
piecemeal
fashion
without
adequate
resources.
EPA
is
sensitive
to
the
concern
that
36772
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/
Vol.
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No.
129
/
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7,
1998
/
Proposed
Rules
generating
the
data
and
developing
the
analytical
capacity
to
incorporate
biological
criteria
into
water
quality
standards
may
present
a
significant
resource
challenge
to
some
States
and
Tribes.
Advocates
for
a
requirement
for
States
and
authorized
Tribes
to
adopt
biological
criteria
argue
that
States
and
Tribes
will
not
implement
biological
criteria
in
a
timely
manner,
if
at
all,
without
an
explicit
Federal
regulatory
requirement.
The
viewpoint
has
been
expressed
that
States
and
authorized
Tribes
will
not
adequately
increase
program
emphasis
or
resources
if
biological
criteria
are
not
required
and,
as
a
consequence,
biological
criteria
will
be
relegated
to
a
lesser
role
then
chemical
water
quality
criteria
or
whole
effluent
toxicity.
Some
States
have
either
direct
(
i.
e.
executive
orders,
legislative
mandates)
or
indirect
limitations
on
adopting
new
regulations
and
policies
that
are
more
stringent
than
that
required
by
Federal
legislation.
Adopting
biological
criteria
may
be
seen
in
some
States
and
Tribes
as
exceeding
minimum
Federal
requirements.
Concern
has
been
expressed
that
without
biological
criteria
as
a
fundamental
component
of
a
State
or
Tribal
water
quality
standards
program,
transition
of
water
quality
standards
programs
to
a
more
integrated
ecosystem
approach
with
an
emphasis
on
watersheds
will
not
succeed.

Adoption
of
Narrative
Biological
Criteria
As
an
alternative
to
requiring
adoption
of
numeric
biological
criteria,
EPA
could
require
States
and
Tribes
to
adopt
a
narrative
biological
criteria.
The
narrative
biological
criteria
could
be
a
statement
of
intent
adopted
in
a
State's
or
Tribe's
water
quality
standards
to
formally
consider
the
fate
and
status
of
aquatic
biological
communities
and
to
establish
the
framework
for
the
consistent
and
quantitative
translation
of
a
State's
or
Tribe's
designated
aquatic
life
uses
and
development
of
numeric
biological
criteria.
EPA
has
published
a
document
on
procedures
for
initiating
narrative
biological
criteria
(
EPA
 
822
 
B
 
92
 
002).
An
example
of
a
narrative
biological
criteria
based
upon
that
publication
follows:

The
State
will
preserve,
protect,
and
restore
the
water
resources
in
their
most
natural
condition
deemed
attainable.
The
condition
of
these
water
bodies
shall
be
determined
from
the
measures
of
physical,
chemical,
and
biological
characteristics
of
each
surface
water
body
type,
according
to
its
designated
use.
As
a
component
of
these
measurements,
the
biological
quality
of
any
given
water
system
shall
be
assessed
by
comparison
to
a
reference
condition(
s)
based
upon
similar
regional
hydrologic
and
watershed
characteristics
(
reference
standardized
methods
and
operating
protocols).
Where
attainable,
such
reference
conditions
or
reaches
of
water
courses
shall
be
those
observed
to
support
the
variety
and
abundance
of
aquatic
life
in
the
region
as
is
expected
to
be
or
has
been
historically
found
in
natural
settings
essentially
undisturbed
or
minimally
disturbed
by
human
impacts,
development
or
discharges.
This
condition
shall
be
determined
by
consistent
sampling
and
reliable
measures
of
selected
indicated
communities
of
flora
and/
or
fauna
as
established
by
[
cite
appropriate
State
agency
or
agencies]
and
may
be
used
in
conjunction
with
acceptable
chemical,
physical,
and
microbial
water
quality
measurements
and
records
judged
to
be
appropriate
to
this
purpose.
Regulations
and
other
management
efforts
relative
to
these
criteria
shall
be
consistent
with
the
objective
of
preserving,
protecting
and
restoring
the
most
natural
communities
of
fish,
shellfish,
and
wildlife
attainable
in
these
waters;
and
shall
protect
against
degradation
of
the
highest
existing
or
subsequently
attained
uses
or
biological
conditions
pursuant
to
State
antidegradation
requirement.

EPA
is
considering
what
could
constitute
approvable
narrative
biological
criteria
and
the
feasibility
of
EPA
promulgating
narrative
biological
criteria
where
a
State
or
Tribe
fails
to
adopt
such
criteria.

Time
Frame
for
Adoption
of
Biological
Criteria
in
State
and
Tribal
Water
Quality
Standards
In
1991
EPA
issued
a
policy
that
established
as
a
long­
term
Agency
goal
the
development
and
adoption
of
biological
criteria
in
State
and
Tribal
water
quality
programs
(
Transmittal
of
Final
Policy
on
Biological
Assessments
and
Criteria,
memorandum
from
Tudor
Davies,
Director
of
the
EPA
Office
of
Science
and
Technology,
to
Regional
Water
Management
Division
Directors,
June,
1991).
EPA
has
identified
as
a
program
priority
during
the
FY1997
 
1999
Water
Quality
Standards
Triennium
that
States
and
Tribes
initiate
and
continue
to
expand
development
of
scientifically
defensible
biological­
based
classification
systems
(
FY
1997
 
1999
Water
Quality
Standards
Priorities,
memorandum
from
Tudor
Davies,
Director
of
the
EPA
Office
of
Science
and
Technology,
July
22,
1996).
Based
on
State
experiences,
development
of
biological
criteria
can
range
between
five
to
ten
years,
depending
on
several
factors
such
as
available
resources,
existing
State
expertise,
existing
data
bases
and
geographic
variability.
If
EPA
were
to
require
or
recommend
that
States
and
Tribes
adopt
biological
criteria,
EPA
would
need
to
determine
appropriate
time
frames
for
adoption
and
implementation
of
these
criteria.
EPA
is
considering
whether
the
following
are
reasonable
and
appropriate
time
frames
for
adoption
of
biological
criteria
in
State
and
Tribal
water
quality
programs:
1.
narrative
biological
criteria
for
streams
and
an
implementation
plan
for
development
of
quantitatively­
based
biological
criteria
for
streams
in
the
2000
 
2003
Water
Quality
Standards
Triennium.
2.
narrative
biological
criteria
and
an
implementation
plan
for
development
of
quantitatively­
based
biological
criteria
for
other
applicable
water
body
types
(
e.
g.
lakes
and
reservoirs,
estuaries
and
near
coastal
waters,
large
rivers
and
wetlands)
within
ten
years
following
EPA
publication
of
technical
guidance.

Linkage
of
Biological
Criteria
to
Stressor­
Identification
One
of
the
potential
benefits
of
developing
a
biological
criteria
program
is
the
increased
ability
to
assess
water
quality
impairment
due
to
nonpoint
source
pollution,
broadening
the
scope
of
most
water
quality­
based
programs
beyond
regulation
of
effluent
discharges.
However,
many
currently
regulated
point
source
dischargers
are
skeptical
that
greater
focus
on
nonpoint
source
would
actually
occur,
particularly
considering
the
time
and
resource
constraints
on
most
State
and
Tribal
programs.
Industry
and
municipalities
are
concerned
that
biological
criteria
bring
an
additional
layer
of
regulatory
and
associated
costs
and
that
they
may
be
an
easy
target
for
additional
requirements
whether
their
discharge
is
the
source
of
impairment
or
not.
EPA
recognizes
that
the
role
biological
assessments
and
criteria
will
play
to
help
identify
specific
stressors
or
sources
of
use
impairment
will
need
to
be
carefully
defined
and
is
interested
in
practical,
effective
approaches
to
evaluate
potential
stressors
and
sources
of
impairment
when
a
water
body
fails
biological
criteria.

Request
for
Comment
on
Biological
Criteria,
Assessment
and
Implementation
EPA
is
soliciting
comment
on
the
following
questions:
1.
Should
EPA
amend
the
regulation
to
explicitly
require
States
and
Tribes
to
adopt
biological
criteria
or
are
there
alternative
approaches
that
EPA
should
consider?
Should
EPA
seek
to
ensure
that
biological
criteria
will
be
developed
and
implemented
in
all
State
and
Tribal
water
quality
programs?
2.
If
EPA
were
to
explicitly
require
States
and
Tribes
to
adopt
biological
36773
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
criteria,
should
it
require
a
narrative
only,
or
a
combination
of
both
narrative
and
numeric
criteria
as
described
in
the
draft
implementation
guidance
(
e.
g
quantitatively­
based
biological
criteria)?
What
should
EPA
promulgate
if
a
State
or
Tribe
fails
to
adopt
biological
criteria
in
its
water
quality
standards?
3.
If
EPA
were
to
explicitly
require
biological
criteria,
what
is
a
reasonable
time
frame
for
State
or
Tribal
adoption?
4.
What
are
practical,
effective
approaches
to
identify
and
evaluate
potential
stressors
and
sources
of
impairment
when
a
water
body
fails
biological
criteria?
5.
In
what
ways
can
biological
criteria
and
biological
assessments
be
used
to
effectively
manage
known
stressors
or
sources
of
impairment,
including
urban
and
rural
runoff?

12.
Wildlife
Criteria
Wildlife
criteria
are
designed
to
protect
mammals
and
birds
from
adverse
impacts
from
pollutants
due
to
consumption
of
food
or
water
from
a
water
body.
A
wildlife
criteria
methodology
applicable
to
the
Great
Lakes
Basin
and
a
few
wildlife
criteria
were
published
as
part
of
the
Great
Lakes
Guidance.
EPA
does
not
have
an
active
wildlife
criteria
guidance
program
at
this
time
but
it
is
a
potential
emerging
criteria
program.
The
wildlife
criteria
that
EPA
promulgated
in
the
Great
Lakes
Guidance
are
for
the
following
four
chemicals:
DDT
(
and
metabolites),
mercury,
PCBs,
and
dioxin
(
2,3,7,8
 
TCDD).

Request
for
Comment
on
Wildlife
Criteria
EPA
requests
comment
on
the
following
question:
1.
Does
the
regulation
need
to
be
clarified
to
specifically
address
the
development
of
wildlife
criteria
guidance
for
the
protection
of
aquatic
dependent
wildlife?

13.
Physical
Criteria
Physical
criteria
is
a
concept
that
takes
into
account
the
physical
attributes
of
the
aquatic
environment,
such
as
quality
of
habitat
and
hydrologic
balance.
Commenters
on
the
draft
ANPRM
identified
physical
habitat
and
hydrologic
balance
criteria
as
additional
important
forms
of
criteria
that
should
be
discussed
in
the
ANPRM.
EPA
agrees
that
physical
habitat
parameters,
including
flow,
are
important
and
often
overlooked
parameters
that
influence
and
at
some
sites
control
whether
or
not
an
aquatic
life
use
is
or
will
be
attained.
For
example,
research
referenced
by
Schueler
(
see
Schueler,
T.
The
Importance
of
Imperviousness.
Watershed
Protection
Techniques,
Fall
1994)
suggests
that
in
many
small
urban
streams
substantial
loadings
from
municipal
separate
storm
sewer
systems
are
severely
degrading
the
aquatic
habitat.
The
authors
suggest
that
the
primary
cause
of
this
habitat
impairment
is
the
high
volume
and
velocity
of
the
storm
water
flows
into
this
type
of
stream.
The
high
flows
exceed
the
peaks
in
the
natural
flow
regime
of
these
streams
and
as
a
result
stream
bank
erosion,
turbidity
and
siltation
occur
and
the
local
habitat
is
degraded.
Further
habitat
destruction
in
larger
downstream
receiving
waters
often
results
from
the
physical
deterioration
of
the
upstream
urban
systems.
For
example,
some
recent
studies
have
shown
that
in
some
lakes
the
biggest
source
of
silt
and
sediment
deposition
into
the
lake
is
actually
from
the
eroded
material
that
comes
directly
out
of
the
stream
bed
and
stream
banks
that
are
scoured
out
during
elevated
wet
weather
peak
discharges
and
extended
hydrographs.
This
can
lead
to
eutrophication,
increased
turbidity,
decreased
light
penetration,
submerged
aquatic
vegetation
(
SAV)
loss,
spawning
bed
smothering,
and
shellfish
habitat
damage.
Studies
of
this
phenomenon
suggest
that
until
these
man­
made
flow
regimes
are
better
managed
and
the
resulting
stresses
to
physical
habitat
corrected,
no
amount
of
control
of
pollutants
is
likely
to
restore
the
aquatic
ecosystem
to
a
level
more
closely
resembling
a
natural
state.
The
character
of
natural
waters
is
obviously
affected
by
wet
weather
events.
Flowing
waters,
especially,
can
change
dramatically
with
the
seasons
and
in
response
to
specific
precipitation
events.
Seasonal
and
event
driven
changes
in
flows,
sediment
loads,
temperature,
etc.
are
common
and
natural
processes
which
are
integral
to
the
maintenance
of
natural
waters
and
their
aquatic
communities.
Humancaused
changes
to
the
landscape,
however,
have
altered
these
natural
processes,
and
for
many
waters,
the
altered
flows
and
the
contamination
now
associated
with
wet
weather
discharges
(
discharges
that
occur
in
whole
or
in
part
as
the
result
of
wet
weather
events)
present
significant
environmental
problems.
Although
these
problems
are
generally
well
recognized,
they
have
been
difficult
to
address
effectively
precisely
because
of
their
magnitude
and
variable
nature.
The
CWA's
objectives
include
the
protection
and
restoration
of
the
physical
integrity
of
our
nation's
waters.
Scientific
experts
agree
that
overall
physical
habitat
loss
is
the
single
biggest
factor
in
the
loss
of
aquatic
species.
Physical
habitat
damage
and
loss
to
the
nation's
waters
includes:
(
1)
Wetlands
losses;
(
2)
the
denuding
of
stream
banks
through
unwise
forestry,
farming,
mining,
and
urbanization;
(
3)
the
embedding
of
stream
bottoms
with
finegrained
silt
from
poorly
designed
and
managed
farm
and
construction
sites;
(
4)
the
damming
of
river
systems;
(
5)
the
channelization
and/
or
concrete
lining
of
rivers
and
streams;
(
6)
the
obliteration
of
ephemeral
and
first­
order
streams
and
springs
during
urbanization
and;
(
7)
the
widening
and
deepening
of
stream
channels
due
to
high­
velocity
urban
storm
flows.
All
seven
of
these
phenomena
are
common
forms
of
aquatic
habitat
damage
and
loss,
and
yet
there
is
little
national
guidance
to
address
the
physical
parameters
that
contribute
to
these
impacts.
In
addition,
EPA
does
not
have
a
clear
picture
of
how
often
physical
habitat
parameters,
including
flow
are
used
by
States
and
Tribes
to
assess,
manage,
and/
or
regulate
activities
that
damage
habitat.
Some
commenters
on
the
draft
asserted
that
water
quality
criteria
guidance
is
needed
to
address
these
forms
of
habitat
loss,
to
create
threshold
values
to
protect
designated
uses
and
to
provide
measuring
tools
for
monitoring
watershed
and
water
body
health.
EPA
agrees
that
further
investigation
of
the
role
of
physical
habitat
parameters,
including
hydrologic
balance,
in
water
quality
standards
programs
is
necessary.
EPA
is
considering
the
relative
importance
of
such
criteria
guidance
as
compared
to
other
forms
of
criteria
guidance
such
as
ambient
water
quality
criteria,
sediment
criteria
and
biological
criteria;
and
on
the
likelihood
that
States
and
Tribes
would
develop
and
implement
such
criteria
if
technical
guidance
and
supporting
policy
were
available.
EPA
is
also
interested
in
identifying
examples
of
where
such
criteria
guidance
has
already
been
used
as
the
basis
for
assessing,
managing
and
protecting
water
quality.
With
respect
to
hydrologic
balance,
EPA
discusses
the
issue
in
the
antidegradation
section
of
this
ANPRM.
Some
commenters
on
the
draft
ANPRM
suggested
that
maintaining
hydrologic
balance
in
surface
waters,
though
important
in
the
context
of
antidegradation,
is
also
important
for
other
aspects
of
water
quality
standards.
These
commenters
suggested
that
hydrologic
balance
should
be
part
of
basic
water
quality
criteria
guidance
for
watershed
and
water
body
assessment
and
for
long­
term
urban
storm
water
abatement
and
prevention
plans
under
36774
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
the
storm
water
NPDES
program,
as
well
as
for
the
traditional
NPDES
program.
EPA
is
further
interested
in
issues
associated
with
hydrologic
imbalances
created
by
various
industries
and
land
operations,
and
the
options
for
researching
and
creating
a
set
of
hydrologic
balance
criteria
guidance.
These
could
include,
for
instance,
regional
minimum
stream
flow
criteria
on
a
seasonal
or
average
monthly
basis,
a
groundwater­
recharge
criterion
meant
to
maintain
adequate
stream
base
flow,
and
a
peak­
flood
and
bank
full
discharge
prevention
criterion,
perhaps
based
on
hydrologic
regions
of
the
country.

Request
for
Comment
on
Physical
Criteria
EPA
seeks
comment
on
the
following
questions:
1.
Would
it
be
useful
to
explicitly
identify
physical
criteria
such
as
habitat
and
hydrologic
balance
in
40
CFR
131
as
a
valid
form
of
criteria
that
States
and
Tribes
can
adopt
in
their
water
quality
standards?
2.
Would
EPA
technical
guidance
on
physical
criteria
be
useful
to
States
and
Tribes?
Is
it
necessary?
3.
What
are
some
examples
of
physical
criteria
that
are
being
used
today
and
what
are
they
being
used
for?
4.
What
should
be
the
principal
uses
for
physical
criteria?
Would
these
help
address
pulsed
or
intermittent
impacts,
such
as
those
from
urban
and
rural
runoff?

14.
Human
Health
Human
health
water
quality
criteria
are
scientifically
derived
values
developed
by
States,
Tribes,
or
EPA
to
protect
human
health
from
the
deleterious
effects
of
carcinogens
and
noncarcinogenic
toxicants.
Human
health
criteria
take
into
account
the
health
effects
from
the
consumption
of
aquatic
organisms
and
drinking
water.
Human
health
criteria
are
based
on
the
potential
of
carcinogens
and
noncarcinogenic
toxicants
to
cause
adverse
impacts
to
human
health.
When
adopting
criteria
to
protect
human
health,
a
State
or
Tribe
may
use
EPA's
Section
304(
a)
criteria
documents
or
other
information
on
factors
to
derive
human
health
criteria.
However,
if
a
State
or
Tribe
decides
to
adopt
criteria
less
stringent
than
recommended
by
EPA,
the
State
or
Tribe
must
provide
documentation
which
supports
that
the
approach
is
based
on
sound
scientific
rationale.
Changes
to
the
Human
Health
Criteria
Methodology
are
anticipated
for
proposal
in
the
Federal
Register
in
1998.
These
changes
to
the
1980
ambient
water
quality
criteria
(
AWQC)
derivation
guidelines
(
45
FR
79347)
are
intended
to
reflect
the
many
significant
scientific
advances
that
have
occurred
during
the
past
17
years
in
such
key
areas
as
cancer
and
noncancer
risk
assessments,
exposure
assessments
and
bioaccumulation.
Comments
on
any
of
the
key
area
issues,
as
well
as
implementation
issues,
are
welcome
and
should
be
made
during
the
public
comment
period
following
the
anticipated
1998
proposal.
The
following
discussion
focuses
on
three
key
policy­
related
issues,
including:
choice
of
risk
levels;
fish
consumption
assumptions
and
environmental
justice,
and
the
use
of
maximum
contaminant
levels.
a.
Risk
Levels.
Criteria
for
specific
pollutants
for
the
protection
of
human
health
rely
in
part
on
risk
levels
(
incidence
of
cancer).
Numeric
criteria
for
carcinogens
are
based
on
three
interrelated
assumptions:
exposure,
cancer
potency,
and
risk
level.
Exposure
considerations
are
based
on
a
wide
range
of
factors,
including
an
estimate
of
the
rate
of
fish
and
drinking
water
consumption,
an
estimate
of
the
body
weight
of
an
exposed
individual,
and
an
estimate
of
the
rate
of
a
chemical's
relative
tendency
to
bioaccumulate
in
fish
tissue
as
compared
to
the
surrounding
water.
Cancer
potency
factors
(
q1*)
provide
a
measure
of
a
chemical's
potential
to
cause
cancer,
and
are
typically
derived
from
studies
on
laboratory
animals.
The
risk
level
represents
an
incremental
increase
in
cancer
incidences
resulting
from
exposure
to
the
chemical.
EPA
guidance
sets
forth
a
range
of
criteria
values
that
result
in
calculated
risk
levels
of
10
¥
5,
10
¥
6,
and
10
¥
7
for
informational
purposes.
Most
States
and
Tribes
select
either
a
10
¥
5
or
10
¥
6
risk
level
as
an
appropriate
value,
i.
e.,
one
additional
cancer
incidence
per
one
hundred
thousand
or
one
million
exposed
individuals,
respectively.
This
level
seems
to
represent
some
general
scientific
and
public
consensus
that
the
cancer
risks
are
acceptably
small
or
insignificant.
States
and
Tribes,
however,
are
not
limited
to
selecting
among
the
risk
levels
published
in
the
CWA
section
304(
a)
guidance
documents.
If
exposure
assumptions
are
changed,
while
the
assumed
risk
level
remains
the
same,
the
criterion
will
change
accordingly.
The
risk
to
people
who
intake
more
than
the
default
exposure
assumptions
increases
with
the
degree
of
change
in
the
intake
rates.
For
example,
if
the
State
or
Tribe
chooses
to
protect
at
a
risk
level
of
10
¥
5
and
assumes
a
fish
consumption
rate
of
6.5
gm/
day,
but
some
individuals
within
the
State
or
Tribe
actually
eat
65
gm/
day
of
fish,
the
criterion
actually
protects
those
individuals
at
a
risk
level
of
1
x
10
¥
4
(
one
additional
cancer
case
per
10,000
people).
The
risk
level
can
change
based
on
the
relative
change
in
each
parameter.
When
adopting
these
standards,
States
and
Tribes
are
strongly
encouraged
to
provide
documentation
that
the
assumptions
made
in
establishing
the
criteria
are
reasonable
and
adequately
protect
the
population,
including
highly
exposed
subpopulations
at
the
risk
level
asserted
in
the
States'
and
Tribes'
standards.
EPA
strongly
encourages
States
and
Tribes
to
highlight
these
provisions
of
their
standards
during
the
public
participation
process.
EPA's
current
criteria
documents
indicate
the
risk
level
within
a
range
of
10
¥
5
to
10
¥
7
for
the
general
population.
The
policy
has
been
to
allow
States
and
Tribes
to
select
appropriate
risk
levels
and
is
consistent
with
the
framework
of
the
CWA
that
recognizes
and
supports
State
and
Tribal
primacy
in
making
risk
management
decisions
to
protect
its
population
provided
that
the
goals
of
the
Act
are
met.
EPA's
approval
of
different
cancer
risk
levels
to
protect
human
health
in
different
States
or
Tribes
is
subject
to
debate.
Many
have
questioned
States'
and
Tribes'
selection
and
EPA's
approval
of
various
risk
levels
to
protect
human
health.
Some
assert
that
EPA
should
require
all
States
and
Tribes
to
adopt
a
single
risk
level.
Others
believe
EPA
should
require
States
and
Tribes
to
develop
data
on
the
different
exposure
assumptions
that
may
be
present
within
the
State
or
Tribe.
With
regard
to
subpopulations
that
may
consume
higher
amounts
of
fish
than
is
assumed
for
the
general
population,
EPA's
Great
Lakes
Guidance
stated
that
a
risk
level
of
10
¥
4
for
such
subpopulations
in
the
Great
Lakes
basin
can
be
protective.
In
a
draft
proposal
of
the
water
quality
criteria
methodology
revisions,
EPA
is
considering
proposing
that
risk
levels
in
the
range
of
10
¥
4
to
10
¥
6
be
adopted
in
deriving
criteria.
However,
the
proposed
revisions
also
note
that
care
must
be
taken
in
situations
where
the
AWQC
includes
fish
intake
levels
based
on
the
general
population
to
ensure
that
the
risk
to
more
highly
exposed
subgroups
(
subsistence,
minority)
does
not
exceed
the
10
¥
4
risk
level.
Furthermore,
EPA
is
considering
proposing
the
10
¥
6
risk
level
as
the
level
that
ensures
protection
for
all
exposed
population
groups.
As
stated
before,
all
comments
regarding
methodology,
including
risk
levels,
36775
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
should
be
made
during
the
public
comment
period
following
the
anticipated
1998
Human
Health
Criteria
Methodology
proposal.
EPA
intends
to
foster
consistent
approaches
between
Agency
program
offices,
including
its
approach
to
determining
allowable
risk
levels.
The
Food
Quality
Protection
Act
of
1996
(
FQPA)
amended
the
Federal
Food,
Drug
and
Cosmetic
Act
(
FFDCA)
to
prohibit
EPA
from
issuing
tolerances
for
pesticide
residues
in
or
on
food
unless
the
Agency
determined
that
there
is
a
``
reasonable
certainty''
that
the
residues
will
result
in
``
no
harm.''
Tolerances
are
allowable
levels
of
chemicals
in
food;
food
containing
residues
in
excess
of
a
tolerance
may
not
be
sold
in
commerce.
The
legislative
history
of
FQPA
indicated
Congressional
support
for
EPA's
view
that
reasonable
certainty
of
no
harm
would
generally
be
met
when
a
non­
threshold
risk
is
below
a
10
¥
6
level.
For
threshold
risks,
the
legislative
history
contained
general
support
for
a
margin
of
safety
of
100,
except
that
the
Statute
required
the
Agency
to
add
an
additional
10­
fold
margin
of
safety
to
protect
infants
and
children,
unless
the
Agency
concluded
on
the
basis
of
reliable
data
that
a
different
margin
would
be
safe
for
infants
and
children.
In
determining
whether
dietary
exposures
are
safe,
the
FQPA
also
directs
EPA
to
consider
nonoccupational
exposures
to
chemicals
used
as
pesticides,
and
to
aggregate
risks
from
chemicals
that
share
a
common
mechanism
of
toxicity.
EPA's
Office
of
Pesticide
Programs
is
in
the
process
of
developing
new
policies
in
response
to
the
FQPA.
EPA's
Office
of
Water
will
consider
these
policies
when
they
are
completed.
b.
Fish
Consumption
Assumptions.
EPA's
recommended
human
health
criteria
under
CWA
section
304(
a)
guidance
are
currently
derived
with
a
fish
consumption
rate
of
6.5
grams
per
day
(
roughly
one
quarter
ounce
of
fish
and
shellfish).
This
value
represents
an
average
based
on
market
survey
data
gathered
in
1973
 
74,
and
reflects
a
national
average
for
all
consumers
and
nonconsumers
of
fish
and
shellfish
from
estuarine
and
fresh
waters.
Again,
EPA
intends
to
propose
revisions
to
the
human
health
methodology
for
deriving
ambient
water
quality
criteria,
including
revisions
of
the
fish
consumption
rate.
Some
assumptions
regarding
fish
consumption
and
criteria
policy
are
also
discussed
in
FR
Vol.
61,
No.
239,
65183
(
December
11,
1996).
EPA
recognizes
that,
while
important,
the
national
fish
consumption
estimate
is
one
of
many
different
parameters
used
to
set
ambient
water
quality
criteria
to
protect
human
health
and
that
the
interactions
of
these
parameters
adds
substantial
complexity
to
the
methodology.
However,
because
this
component
is
easily
understood,
it
receives
the
most
attention
from
the
general
public.
Overall,
EPA
considers
its
human
health
criteria
methodologies
to
be
conservative
and
protective
of
human
health.
EPA
also
recognizes
that
there
are
subpopulations
that
consume
greater
quantities
of
fish
and
has
considered
this
as
part
of
the
human
health
methodology
for
developing
water
quality
criteria.
State
and
Tribal
human
health
criteria
are
often
based
on
a
risk
level
of
10
¥
5
or
10
¥
6
to
protect
people
inclined
to
consume
higher
quantities
than
the
average.
In
addition,
with
regulatory
actions
for
carcinogens,
individuals
consuming
even
20
times
the
6.5
gram
amount
would
still
be
protected
at
the
10
¥
4
risk
level.
(
EPA
is
not
proposing
a
national
risk
level
of
10
¥
4
here,
rather
EPA
is
acknowledging
that
the
level
of
risk
is
relative
to
the
consumption
of
fish
(
i.
e.,
it
is
greater
for
individuals
consuming
more
fish
than
the
national
average).
A
similar
rationale
for
the
protectiveness
of
a
criterion
may
not
apply
to
non­
carcinogenic
pollutants
(
i.
e.,
RfD­
based
chemicals),
where
significantly
higher
fish
consumption
rates
may
(
when
combined
with
other
exposure
sources)
result
in
exposures
significantly
exceeding
the
RfD.
Although
there
are
safety
factors
associated
with
an
RfD,
they
are
related
to
uncertainties
associated
with
the
toxicological
evaluation,
not
with
the
sources
and
levels
of
exposure.
Therefore,
significantly
higher
intakes
may
require
more
stringent
criteria
to
protect
human
health.
EPA
is
seeking
ways
to
implement
Executive
Order
12898
(
February
16,
1994,
59
FR
7629)
regarding
environmental
justice
to
ensure
that
water
quality
criteria
are
developed
taking
into
account
populations
such
as
Native
Americans
and
other
minorities,
as
well
as
other
subsistence
fishers.
This
would
include
working
with
the
scientific
community
and
the
public
to
improve
EPA's
health
assessments
and
risk
assessments
and
incorporate
relevant
issues
into
its
policies
and
guidance.
This
also
includes
mechanisms
for
public
participation
(
e.
g.,
meetings)
for
the
purposes
of
factfinding
receiving
comments,
and
conducting
inquiries
concerning
environmental
justice.
Relevant
to
water
quality
standards,
EPA
recognizes
the
need
to
address
issues
regarding
different
fish
consumption
patterns
among
subsistence,
minority
populations.
EPA
acknowledges
that
these
groups
may
consume
a
greater
quantity
of
fish
than
the
national
average.
In
addition,
these
groups
have
asserted
that
States
and
Tribes
should
be
required
to
take
a
more
aggressive
role
in
protecting
them.
Guidance
for
Assessing
Chemical
Contaminated
Data
for
Use
in
Fish
Advisories
(
Vol.
1
 
IV,
USEPA,
1993
and
1994)
notes
that
fish
and
shellfish
consumption
rates
vary
greatly
for
sections
of
the
U.
S.
population
(
e.
g.,
by
gender,
race,
age,
cultural
and
recreational
activity,
and
income
levels).
Given
the
wide
variations
in
consumption
patterns,
it
would
not
seem
to
be
possible
for
States
and
Tribes
to
provide
the
same
level
of
protection
from
contaminated
fish
for
all
consumers.
EPA
believes
criteria
should
ensure
adequate
protection
of
all
significant
populations
and
subpopulations
from
reasonable
risks.
States
and
Tribes
are
encouraged
to
consider
local
surveys
when
selecting
fish
consumption
rates
to
protect
their
populations
since
the
national
average
value
may
not
be
indicative
of
local
consumption
habits.
In
its
Water
Quality
Guidance
for
the
Great
Lakes
System
(
60
FR
15366,
March
23,
1995),
EPA
included
a
Great
Lakes­
specific
fish
consumption
rate
of
15
grams
per
day.
This
rate
was
based
on
several
fish
consumption
surveys
from
the
Great
Lakes
(
see
60
FR
15366
at
15374,
March
23,
1995.)
EPA
has
also
published
for
external
peer
review
``
Draft
Guidance
for
Conducting
Fish
and
Wildlife
Consumption
Surveys.''
(
U.
S.
EPA
1997).
States
and
Tribes
could
be
encouraged
to
modify
criteria
on
a
site­
specific
basis
to
provide
additional
protection
appropriate
for
highly
exposed
subpopulations.
That
is,
where
high­
end
consumers
would
not
be
adequately
protected
by
criteria
derived
using
the
default
fish
intake
assumption,
the
State
or
Tribe
may
modify
this
assumption
to
provide
appropriate
additional
protection.
Again,
such
a
recommendation
was
made
in
the
Great
Lakes
Guidance.
This
preference
will
also
be
stated
in
the
proposed
revisions
to
the
human
health
methodology
for
deriving
ambient
water
quality
criteria.
c.
Maximum
Contaminant
Levels.
Under
the
Safe
Drinking
Water
Act
(
SDWA),
EPA
develops
chemicalspecific
numeric
values
for
use
in
protecting
public
drinking
water
supplies.
They
are
maximum
contaminant
level
goals
(
MCLGs)
and
maximum
contaminant
levels
(
MCLs).
A
MCLG
is
a
non­
enforceable
concentration
of
a
drinking
water
contaminant
that
is
protective
of
36776
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
adverse
human
health
effects
and
allows
an
adequate
margin
of
safety.
A
MCL
is
the
maximum
permissible
level
of
a
contaminant
in
water
which
is
delivered
to
any
user
of
a
public
water
system.
MCLGs
are
based
solely
on
human
health
considerations
(
i.
e.,
an
identified
adverse
effect
to
human
health,
combined
with
an
exposure
intake
estimate).
In
contrast,
MCLs
are
to
be
as
close
to
the
MCLG
as
feasible,
taking
into
consideration
the
availability
and
the
cost
of
treatment
technologies
as
well
as
the
availability
of
analytical
methodologies.
When
these
two
additional
factors
beyond
health
(
treatment
cost
and
analytical
factors)
are
considered,
the
MCL
for
some
chemicals
is
a
higher
(
i.
e.,
less
stringent)
value
than
the
MCLG.
However,
there
are
also
many
chemicals
for
which
the
MCL
is
equal
to
the
MCLG.
This
is
particularly
true
for
noncarcinogens.
Over
80%
of
all
current
MCLs
for
noncarcinogens
are
identical
to
the
corresponding
MCLG
for
that
substance.
For
carcinogens,
MCLs
are
always
higher
than
MCLGs
because
MCLGs
for
carcinogens
are
routinely
set
to
zero.
Some
States
and
Tribes
utilize
MCLs
and
MCLGs,
as
criteria
to
protect
human
health
under
the
CWA.
For
some
chemicals,
the
MCL
or
MCLG
is
more
stringent
than
CWA
section
304(
a)
human
health
criteria.
In
other
cases,
CWA
criteria
are
more
stringent
than
the
MCL
or
MCLG.
These
differences
come
about
for
three
basic
reasons.
First,
as
noted
above,
the
304(
a)
criteria
under
the
CWA
and
MCLGs
under
the
SDWA
are
strictly
health­
based
values
that
do
not
account
for
treatment
costs
or
analytical
limitations.
The
MCL,
however,
does
take
into
account
treatment
costs
and
analytical
limitations.
Second,
the
methodologies
used
to
calculate
the
304(
a)
criterion
and
the
MCLG
 
both
health­
based
values
 
for
the
same
chemical
often
differ.
Third,
the
MCLG
and
the
304(
a)
criterion
sometimes
have
been
calculated
at
different
times,
often
years
apart,
using
the
current
risk
and
exposure
information
at
the
time.
Where
different
information
on
risk
and
exposure
was
used,
differences
in
the
numerical
values
can
be
expected.
It
is
important
to
consider
some
of
the
methodological
differences
between
the
derivation
of
304(
a)
criteria
and
MCLs
and
MCLGs.
Although
the
methods
under
SDWA
and
CWA
both
use
the
same
reference
dose
(
RfD)
or
cancer
potency
slope,
and
both
methods
assume
a
70
kg
adult
and
consumption
of
2
liters
of
water
per
day,
there
are
several
important
differences.
One
difference
is
that
MCLGs
for
chemicals
that
are
known
or
likely
carcinogens
are
usually
set
equal
to
zero,
while
CWA
section
304(
a)
criteria
for
carcinogens
are
based
on
an
incremental
cancer
risk
level
and
are
never
set
equal
to
zero.
For
chemicals
with
limited
evidence
of
carcinogenicity,
the
MCLG
is
usually
based
on
the
chemical's
reference
dose
(
RfD)
for
noncancer
effects
with
the
application
of
an
additional
uncertainty
factor
of
1
to
10
to
account
for
its
possible
carcinogenicity.
In
contrast,
the
1980
CWA
section
304(
a)
criteria
guidelines
do
not
differentiate
among
carcinogens
with
respect
to
the
weight
of
evidence
grouping;
all
were
derived
based
on
lifetime
carcinogenic
risk
levels.
Another
important
difference
between
the
two
methodologies
is
that
a
single
determined
risk
value
(
single
reference
dose
or
single
cancer
risk
value
within
the
10
¥
4
to
10
¥
6
range)
is
used
in
setting
an
MCLG,
while
CWA
section
304(
a)
criteria
have
been
derived
for
each
of
the
three
incremental
risk
levels
spanning
10
¥
5
to
10
¥
7,
with
the
decision
on
which
value
to
adopt
left
to
the
State
or
Tribe.
Another
important
methodological
difference
is
in
the
approach
to
accounting
for
exposure
sources.
MCLGs
for
RfD­
based
chemicals
developed
under
the
SDWA
follow
a
relative
source
contribution
(
RSC)
approach
in
which
the
percentage
of
exposure
that
is
attributed
to
drinking
water
is
determined
relative
to
the
total
exposure
from
all
sources
(
e.
g.,
drinking
water,
food,
air).
The
rationale
for
this
approach
is
to
ensure
that
an
individual's
total
exposure
to
a
chemical
does
not
exceed
the
RfD.
To
develop
CWA
human
health
criteria
for
noncarcinogens,
the
1980
CWA
National
Guidelines
recommended
taking
nonfish
dietary
sources
and
inhalation
into
account.
However,
data
on
these
other
sources
were
generally
not
available.
Therefore,
it
was
typically
assumed
that
an
individual's
total
exposure
to
a
chemical
came
solely
from
drinking
water
from
the
water
body
and
consumption
of
fish
and
shellfish
living
in
the
water
body.
Also,
CWA
criteria
are
based
on
a
prediction
of
exposure
from
fish
and
shellfish
using
a
bioconcentration
factor
(
BCF)
to
estimate
the
bioconcentration
of
the
individual
chemical,
and
a
fish/
shellfish
consumption
rate.
To
date,
under
the
current
MCLG
methodology,
BCFs
have
not
been
used
in
the
exposure
estimates
and
fish/
shellfish
consumption
rates
have
been
only
marginally
accounted
for
(
e.
g.,
via
general
FDA
dietary
estimate
or
conservative
default
assumption).
Because
of
the
differences
in
the
approach
to
exposure
and
the
basis
of
toxicity
values,
the
health­
based
drinking
water
goal
(
MCLG)
is
sometimes
more
stringent
than
the
CWA
human
health
criterion
(
304(
a)
criterion).
However,
the
opposite
is
sometimes
true.
An
example
of
the
former
is
1,4­
dichlorobenzene,
for
which
both
the
MCL
and
MCLG
are
75
ug/
L
and
the
304(
a)
criterion
(
for
protection
of
human
health
from
the
exposures
of
drinking
water
and
consuming
contaminated
fish)
is
400
ug/
L.
In
this
case,
the
MCLG
was
developed
based
on
an
assumption
that
20%
of
the
total
exposure
is
from
drinking
water
(
the
RSC
factor
applied
to
this
noncarcinogen),
whereas
the
CWA
criterion
effectively
assumes
that
non­
water
exposure
is
negligible.
Additional
sources
of
difference
between
the
two
values
are:
(
1)
the
BCF/
BAF
for
1,4­
dichlorobenzene
is
low
and
thus
does
not
make
the
304(
a)
value
significantly
lower;
(
2)
the
MCLG
was
derived
from
an
RfD
of
0.1
mg/
kg/
day,
while
the
304(
a)
criterion
utilized
an
Acceptable
Daily
Intake
(
ADI,
now
replaced
by
the
use
of
RfDs)
of
0.013
mg/
kg/
day;
and,
(
3)
the
MCLG
included
a
safety
factor
of
10,000,
whereas
the
water
quality
criterion
included
a
safety
factor
of
only
1,000.
In
contrast,
for
noncarcinogens
where
the
BCF/
BAF
is
high,
the
CWA
criteria
may
be
roughly
equivalent
or
more
stringent
than
the
health­
based
drinking
water
levels
because
of
the
considerable
exposure
via
fish/
shellfish
consumption
that
is
assumed
in
deriving
the
CWA
criteria.
As
with
the
previous
example,
the
difference
may
be
compounded
if
the
toxicological
values
have
a
different
basis.
An
example
is
endrin,
for
which
the
MCL
and
MCLG
are
2
ug/
L
and
the
CWA
section
304(
a)
human
health
criterion
(
again,
for
protection
from
the
exposures
of
drinking
water
and
consuming
contaminated
fish)
is
0.76
ug/
L.
In
this
case,
the
drinking
water
level
is,
again,
developed
based
on
the
RSC
assumption
of
20%,
whereas
the
CWA
criterion
assumes
that
non­
water
exposure
is
negligible.
However,
the
BCF/
BAF
for
endrin
is
quite
high
(
3,970)
and
drives
the
304(
a)
value
significantly
lower.
Furthermore,
the
MCLG
was
derived
from
an
RfD
of
3.0
´
 
10
¥
4
mg/
kg/
day,
while
the
CWA
criterion
utilized
an
ADI
of
1.0
´
 
10
¥
3
mg/
kg/
day.
With
endrin,
both
the
MCLG
and
the
water
quality
criterion
included
a
safety
factor
of
100.
Of
course
as
noted
above,
the
MCL
takes
into
account
the
cost
or
availability
of
treatment
technology
or
analytical
methods,
and
may
be
much
less
stringent
than
the
CWA
human
health
criterion,
regardless
of
the
36777
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Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
exposure
assumptions
or
toxicological
basis
(
e.
g.,
1,1,2­
trichloroethane).
Because
of
the
differing
methods
used
to
implement
the
SDWA
and
the
CWA,
EPA
has
recommended
that,
where
consideration
of
available
treatment
technology,
costs,
or
availability
of
analytical
methodologies
has
resulted
in
MCLs
that
are
less
protective
than
MCLGs
or
CWA
section
304(
a)
criteria,
States
and
Tribes
should
consider
using
MCLGs
and/
or
health­
based
CWA
section
304(
a)
criteria
to
protect
surface
waters
that
are
designated
for
water
supply
use
under
the
State's
or
Tribe's
water
quality
standards.
Furthermore,
when
adopting
water
quality
criteria
to
protect
a
surface
water
designated
for
drinking
water
supply
use,
States
and
Tribes
should
carefully
consider
what
value
(
e.
g.,
the
MCLG
or
the
304(
a)
value)
provides
a
defensible
estimate
of
the
water
quality
level
necessary
to
fully
protect
the
use,
and
whether
relevant
exposure
routes
have
been
adequately
considered
in
the
derivation
of
each
value.
EPA
stated
its
policy
on
the
use
of
Section
304(
a)
human
health
criteria
versus
MCLs
in
45
FR
79318,
November
28,
1980.
Additionally,
a
memorandum
from
R.
Hanmer
to
the
EPA
Regional
Water
Management
Division
Directors
dated
December
12,
1988,
provided
detailed
guidance
with
regard
to
this
policy.
Specifically,
for
the
protection
of
public
water
supplies,
EPA
encouraged
the
use
of
MCLs.
When
fish
ingestion
is
considered
an
important
activity,
EPA
recommended
the
use
of
304(
a)
criteria
to
protect
human
health.
In
all
cases,
if
a
304(
a)
criterion
did
not
exist
for
a
chemical,
an
MCL
was
deemed
a
suitable
level
of
protection.
The
forthcoming
proposed
human
health
criteria
guidelines
(
scheduled
for
publication
in
1998
and
cited
above)
are
expected
to
recommend
a
slightly
different
approach.
Although
EPA
considers
the
use
of
MCLs
to
protect
surface
waters
under
the
CWA
to
be
acceptable
in
the
absence
of
304(
a)
criteria,
EPA
expects
to
recommend
that:
 
MCLs
only
be
used
when
they
are
numerically
the
same
as
the
MCLG
and
only
when
the
sole
concern
is
the
protection
of
public
water
supply
sources
(
e.
g.,
where
the
chemically
toxic
form
in
water
is
not
the
form
found
in
fish
tissue
and,
therefore,
fish
ingestion
exposure
is
not
an
issue
of
concern);
 
where
consideration
of
available
treatment
technology,
costs,
or
availability
of
analytical
methodologies
has
resulted
in
MCLs
that
are
different
than
MCLG
values
or
304(
a)
criteria,
States
and
Tribes
consider
using
MCLGs
and/
or
304(
a)
criteria
to
protect
surface
waters
designated
for
water
supply
use;
 
where
fish
consumption
is
an
existing
or
potential
activity,
States
and
Tribes
ensure
that
their
adopted
human
health
criteria
adequately
address
this
exposure
route;
 
where
fish
consumption
is
a
designated
use,
States
and
Tribes
use
304(
a)
criteria
to
protect
that
use
because
fish
consumption
and
bioaccumulation
are
explicitly
addressed
by
the
304(
a)
methodology;
 
where
water
monitored
at
existing
drinking
water
intakes
has
concentrations
at
or
below
MCLGs,
then
the
water
could
be
considered
to
meet
a
CWA
designated
use
as
a
drinking
water
supply
and
a
criterion
reflecting
that
level
could
be
adopted;
and,
 
for
carcinogens
where
the
MCLG
is
equal
to
zero,
States
and
Tribes
base
a
criteria
value
at
the
drinking
water
intake
on
an
acceptable
cancer
risk
level
(
i.
e.,
a
level
within
the
range
of
10
 
4
to
10
 
6),
to
protect
human
health.
It
is
not
intended
that
MCLGs
of
zero
would
be
used
as
the
basis
for
State
or
Tribal
water
quality
criteria.
As
States
and
Tribes
may
be
more
stringent
than
EPA,
States
and
Tribes
may
adopt
an
MCL
or
MCLG
as
a
water
quality
criterion
that
is
more
stringent
than
EPA's
recommended
section
304(
a)
criterion.
In
situations
where
a
recommended
304(
a)
criterion
is
less
protective
than
an
MCL,
EPA
expects
to
recommend
in
the
1998
human
health
criteria
methodology
proposal
use
of
the
MCL
instead
of
the
recommended
304(
a)
criterion
because
it
would
help
to
ensure
adequate
source
water
protection
and
avoid
costly
compliance
problems
for
downstream
water
supply
utilities.
EPA
has
considered
extensively
this
issue
of
equivalency
between
the
drinking
water
component
of
CWA
section
304(
a)
criteria
and
MCLGs
or
MCLs.
EPA
expects
to
move
toward
similar
assessment
methodologies
(
including
its
exposure
and
relative
source
contribution
[
RSC]
policies)
for
deriving
CWA
criteria
and
MCLGs.
Consistent
exposure
evaluation
methodologies
for
deriving
CWA
304(
a)
criteria
for
human
health
protection
and
MCLGs
under
SDWA,
would,
over
time,
eliminate
the
need
to
consider
using
MCLs
for
adopting
State
water
quality
standards.
In
the
meantime,
where
there
are
differences
between
the
MCLG
and
the
304(
a)
criteria
for
human
health
protection,
EPA
expects
to
continue
to
recommend
using
as
the
water
quality
criterion
the
value
that,
in
the
judgement
of
the
State
or
Tribe,
best
accounts
for
the
relevant
routes
of
exposure.
Of
course,
EPA
will
also
approve
use
of
the
more
stringent
value.

Request
for
Comments
on
Human
Health
Criteria
EPA
seeks
public
comment
on
the
following
questions:
1.
Should
the
regulation
require,
or
should
guidance
recommend,
higher
intake
assumptions
for
site­
specific
or
regional
situations
when
subpopulations
that
are
highly
exposed
have
been
identified?
If
so,
what
should
be
the
basis
for
such
intake
assumptions?
2.
Should
the
regulation
be
modified
to
clarify
(
beyond
the
guidance
being
proposed
in
1998)
the
use
of
MCLs
and
MCLGs
in
State
water
quality
standards?
[
Note:
Comments
on
the
establishment
of
similar
assessment
methodologies
for
deriving
CWA
criteria
and
MCLGs
should
be
made
during
the
public
comment
period
following
the
anticipated
1998
Human
Health
Criteria
Methodology
proposal.]

15.
Microbiological
Criteria
Currently
EPA
has
a
criteria
document
titled
``
Ambient
Water
Quality
Criteria
for
Bacteria
 
1986''
which
provides
information
on
microbiological
indicator
organisms,
sampling
frequencies,
and
risk
based
criteria
guidance
which
States
and
Tribes
can
use
in
establishing
State
or
Tribal
standards,
especially
for
recreational
waters.
The
indicators
used
are
the
Enterococci
for
fresh
and
salt
waters
(
33/
100mL
and
35/
100mL
respectively)
and
E.
Coli
for
fresh
waters
(
126/
100mL).
It
is
recommended
that
sampling
be
performed
on
a
weekly
basis
and
the
acceptability
criteria
are
based
on
a
running
average
level
of
the
indicators
on
a
monthly
basis.
The
EPA
Office
of
Research
has
completed
a
new
Enterococci
method
(
See
``
Membrane
Filter
Test
Method
for
Enterococci
in
Water,''
EPA
 
821
 
R
 
97
 
004,
May
1997).
This
indicator
method
allows
samples
to
be
read
in
24
hours
rather
than
the
48
hours
of
the
old
Enterococci
method.
In
1997,
EPA
established
the
Beaches
Environmental
Assessment
Closure
and
Health
Program
(``
BEACH''
Program)
to
protect
the
health
of
beach
goers
through
assistance
to
State,
Tribal,
and
local
health
officials
in
designing,
developing
and
implementing
beach
monitoring
and
advisory
programs.
The
BEACH
Program
will
also
survey
local
beach
authorities
about
their
programs
and
develop
an
Internet
website
to
provide
the
public
with
information
on
local
beach
water
quality
conditions,
36778
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
beach
advisories
and
closures,
and
health
risks
associated
with
swimming
in
contaminated
water.
While
the
Enterococci
and
E.
Coli
indicators
and
criteria
guidance
are
satisfactory
for
determining
risks
from
acute
gastrointestinal
disease
they
are
not
necessarily
acceptable
for
determining
risks
from
enteric
viruses
nor
from
pathogenic
enteric
protozoa
such
as
Giardia
and
Crypto
Sporidium
since
these
pathogens
are
much
more
resistant
environmentally
and
experience
different
treatment
effectiveness.
EPA
is
currently
evaluating
how
it
may
develop
human
health
criteria
for
protection
from
these
organisms.
EPA
may
conduct
additional
research
to
develop
indicator
methods
for
nonenteric
pathogens
that
cause
skin,
respiratory,
eye,
ear,
and
throat
infections
that
are
not
detected
by
the
current
indicator
methods.
EPA
also
intends
to
examine
the
phenomenon
of
regrowth
of
the
current
indicators
on
soil
and
vegetation
in
tropical
areas,
and
if
deemed
necessary
add
indicator
development
studies
to
replace
the
current
indicators
in
tropical
recreational
areas.
Further
studies
are
proposed
to
examine
rapid
chemical
indicators
of
fecal
pollution
to
see
if
a
tiered
sampling
protocol
can
be
established
for
recreational
water
monitoring.
Also,
EPA
plans
to
examine
the
development
of
improved
monitoring
strategies
that
States,
Tribes
and
local
authorities
could
use
to
assess
the
true
impact
of
pollution
during
wet
weather
events.
Finally,
EPA
will
examine
various
computer
models
that
could
be
used
to
predict
microbial
pollution
from
storm
water
events
in
watersheds
and
at
recreational
areas.
These
models
would
be
validated
by
microbiological
monitoring.

Request
for
Public
Comment
on
Microbiological
Criteria
EPA
seeks
public
comment
on
the
following
questions:
1.
Where
and
how
is
it
best
to
conduct
future
programs
to
determine
the
safety
of
recreational
waters?
2.
What
communication
strategies
would
best
inform
the
public
about
pathogen
exposures?
3.
What
guidance
should
EPA
provide
to
States,
Tribes,
and
local
governments
on
how
to
conduct
beach
monitoring
activities?

16.
Nutrient
Criteria
In
the
National
Water
Quality
Inventory
1994
Report
to
Congress,
nutrients
(
nitrogen
and
phosphorous)
are
cited
as
one
of
the
leading
causes
of
water
quality
impairment
in
our
Nation's
rivers,
lakes
and
estuaries.
While
nutrients
are
essential
to
the
health
of
aquatic
ecosystems,
excessive
nutrient
loadings
can
result
in
the
growth
of
aquatic
weeds
and
algae,
leading
to
oxygen
depletion,
increased
fish
and
macro
invertebrate
mortality
and
other
water
quality
impairments.
In
December
1995,
EPA
held
a
National
Nutrient
Assessment
Workshop
with
the
goal
of
developing
a
comprehensive
nutrient
strategy
which
would
provide
tools
that
can
be
used
in
assessing
and
controlling
nutrients
in
all
types
of
water
bodies.
Major
conclusions
from
that
workshop
were:
(
1)
a
single
set
of
national
nutrient
criteria
is
not
a
realistic
goal,
and
(
2)
nutrient
criteria
need
to
be
set
on
an
ecoregional
or
watershed
basis.
EPA
has
since
been
developing
a
national
nutrient
strategy
in
order
to
communicate
the
specific
approach
and
activities
necessary
to
meet
the
goals
and
major
conclusions
of
the
National
Nutrient
Assessment
Workshop.
On
February
14,
1998,
the
``
Clean
Water
Action
Plan''
was
announced
by
the
Administrator
of
EPA
and
the
Secretary
of
Agriculture.
The
``
Clean
Water
Action
Plan''
is
a
blueprint
for
restoring
and
protecting
the
Nation's
precious
water
resources.
As
part
of
this
Action
Plan,
EPA
intends
to
identify
the
major
sources
of
nitrogen
and
phosphorous
in
our
waters
and
to
identify
actions
to
address
these
sources.
In
particular,
EPA
intends
to
accelerate
development
of
nutrient
criteria
guidance
for
waters
in
every
geographic
region
in
the
country,
so
that
EPA
and
the
States
and
Tribes
can
begin
implementing
a
criteria
system
for
nitrogen
and
phosphorous
runoff
for
lakes,
rivers,
and
estuaries
by
the
year
2000.
EPA
will
assist
States
and
Tribes
in
adopting
numeric
water
quality
criteria
for
nitrogen
and
phosphorous,
which
EPA
expects
will
take
the
form
either
of
State­
or
Tribe­
derived
criteria
where
data
is
available,
or
criteria
based
on
EPA
default
ranges
applicable
to
their
ecoregion(
s).
Where
a
State
or
Tribe
does
not
adopt
appropriate
nutrient
standards,
EPA
intends
to
begin
the
process
of
promulgating
nutrient
standards.
To
support
meeting
these
expectations,
EPA
anticipates
the
following
actions
described
below.
First,
EPA
intends
to
publish
a
National
Nutrient
Strategy
which
will
present
currently
available
tools
for
assessing
eutrophication,
identify
important
implementation
issues
related
to
controlling
eutrophication,
and
provide
the
Agency's
plan
for
developing
water
body­
type
guidance
on
nutrient
over
enrichment.
This
national
strategy
will
also
present
EPA's
expectations
for
action
on
the
part
of
States
and
Tribes,
namely,
development
of
numeric
nutrient
criteria
and
standards
on
a
regional/
watershed
basis.
Second,
by
the
end
of
the
year
2000,
EPA
expects
to
publish
the
water
body­
type
guidance
documents
which
would
serve
as
``
user
manuals''
for
assessing
and
controlling
nutrient
over
enrichment
for
specific
water
body
types:
lakes
and
reservoirs,
rivers
and
streams,
and
estuarine
and
coastal
waters.
These
documents
will
include
techniques
for
assessing
the
trophic
state
of
a
water
body
and
a
methodology
for
developing
regionspecific
nutrient
criteria.
In
each
document,
EPA
intends
to
provide
regional
nutrient
ranges
for
phosphorus
and
nitrogen
(
and
other
parameters),
which
EPA
would
expect
States
and
Tribes
to
use
in
setting
nutrient
criteria
in
the
absence
of
any
criterion
that
has
been
developed
site­
specifically.
EPA
intends
to
use
existing
State
and
Tribal
projects
and
data,
supplemented
with
new
regional
case
studies
and
demonstration
projects
that
are
being
conducted
to
collect
information
in
data­
limited
areas
of
the
country.
An
important
component
in
developing
default
nutrient
values
is
determining
the
appropriate
scale
of
application
(
e.
g.,
watershed,
ecoregion,
Northern
lakes/
Southern
lakes,
etc.).
Finally,
in
order
to
promote
the
use
of
the
water
body­
specific
guidance,
and
ensure
the
development
of
nutrient
criteria
on
a
watershed
or
ecoregional
basis
nationwide,
EPA
will
undertake
several
activities,
including:
(
1)
training
in
EPA
regions
and
States,
and
Tribes,
through
the
use
of
Regional
Technical
Assistance
Centers;
(
2)
appointing
EPA
Regional
Nutrient
Coordinators
who
will
oversee
the
development
and
implementation
of
nutrient
criteria
and
standards
in
each
of
the
EPA
Regions;
and
(
3)
offering
assistance
grants
which
will
provide
financial
support
to
States
and
Tribes
in
their
efforts
to
assemble
existing
data,
including
nutrient
endpoint
data,
and
to
establish
nutrient
criteria
either
by
watershed
or
ecoregion,
where
sufficient
data
are
available.

Request
for
Comments
on
Nutrient
Criteria
EPA
requests
comment
on
the
following
questions:
1.
Should
the
regulation
specifically
require
States
and
Tribes
to
adopt
and
implement
numeric
nutrient
criteria?
2.
What
capabilities
do
States
and
Tribes
have
right
now
for
developing
and
implementing
water
quality
criteria
for
nutrients?
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/
Tuesday,
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7,
1998
/
Proposed
Rules
3.
What
are
the
institutional
impediments
to
collecting
nutrient
data
and
developing
nutrient
standards,
for
example,
staff
numbers
and
expertise
and
financial
resources?
4.
Which
States
or
Tribes
are
using
an
ecoregion
or
watershed
approach
to
develop
numeric
nutrient
standards
(
EPA
is
aware
of
some
States
doing
this)?
For
those
States
and
Tribes
that
do
not,
on
what
scale
do
their
nutrient
standards
apply
 
statewide
or
by
water
body
type?

D.
Antidegradation
1.
Background
The
Federal
antidegradation
policy
has
its
roots
in
the
Water
Quality
Act
of
1965
(
Pub.
L.
89
 
234),
which
stated
in
its
declaration
of
policy,
``
The
purpose
of
this
Act
is
to
enhance
the
quality
and
value
of
our
water
resources
and
to
establish
national
policy
for
the
prevention,
control,
and
abatement
of
water
pollution.''
Policy
guidelines
established
by
the
Department
of
the
Interior
in
1966
for
use
in
the
approval
of
States'
water
quality
standards
contained
additional
direction
on
antidegradation,
stating
that
``
In
no
case
will
standards
providing
for
less
than
existing
quality
be
acceptable''
and
``
The
water
quality
standards
proposed
by
a
state
should
provide
for:
.
.
.
The
maintenance
and
protection
of
quality
and
use
or
uses
of
waters
now
of
a
high
quality
or
of
a
quality
suitable
for
present
and
potential
future
uses.''
Secretary
of
the
Interior
Udall
further
defined
the
Federal
policy
on
antidegradation
in
1968,
when
he
said
that
each
State
was
to
include
a
statement
similar
to
the
following
in
their
water
quality
standards:
Waters
whose
existing
quality
is
better
than
the
established
standards
as
of
the
date
on
which
such
standards
become
effective
will
be
maintained
at
their
existing
high
quality.
These
and
other
waters
of
a
State
will
not
be
lowered
in
water
quality
unless
and
until
it
has
been
affirmatively
demonstrated
to
the
State
water
pollution
control
agency
and
the
Department
of
the
Interior
that
such
change
is
justifiable
as
a
result
of
necessary
economic
or
social
development
and
will
not
interfere
with
or
become
injurious
to
any
assigned
uses
made
of,
or
presently
possible
in,
such
waters.
This
will
require
that
any
industrial,
public
or
private
project
or
development
which
would
constitute
a
new
source
of
pollution
or
an
increased
source
of
pollution
to
high
quality
waters
will
be
required,
as
part
of
the
initial
project
design,
to
provide
the
highest
and
best
degree
of
waste
treatment
available
under
existing
technology,
and,
since
these
are
also
Federal
standards,
these
waste
treatment
requirements
will
be
developed
cooperatively.

The
Federal
Water
Pollution
Control
Act
Amendments
of
1972
(
Pub.
L.
92
 
500)
continued
to
emphasize
the
prevention
of
pollution
and,
in
1973,
EPA
developed
guidance
for
State
water
quality
standards
under
the
Amendments
that
essentially
repeated
the
1968
statements
of
Secretary
Udall.
In
1975,
EPA
promulgated
regulations
at
40
CFR
130.17(
e)
that
required
the
States
to
develop
an
antidegradation
policy
and
implementation
procedures.
The
1975
rule
contained
provisions
that
are
very
similar
to
those
in
40
CFR
131.12,
and
provided
protection
for
existing
uses,
high
quality
waters,
high
quality
waters
that
constituted
an
outstanding
National
resource,
and
waters
impaired
by
thermal
discharges.
EPA
issued
final
rules
on
November
8,
1983
(
48
FR
51400)
that
retained,
with
certain
changes,
the
1975
antidegradation
policy
and
incorporated
it
into
the
regulations
at
40
CFR
131.12.
The
changes
to
the
1975
antidegradation
policy
are
discussed
in
the
preamble
to
the
1983
rulemaking
(
48
FR
51402
 
51403),
but
they
were
generally
intended
to
clarify
the
policy
with
no
change
in
coverage
or
effect.
An
exception
to
this
was
the
change
in
the
provisions
applicable
to
outstanding
National
resource
waters,
which
eliminated
the
strict
``
no
degradation''
requirement
in
favor
of
a
limited
exception
for
activities
that
result
in
temporary
and
short­
term
lowering
of
water
quality.
The
1983
regulation
(
40
CFR
131.12(
a))
provides
that
a
State
or
Tribe
is
to
identify
its
method
for
implementing
the
antidegradation
policy,
i.
e.,
decision
measures
for
assessing
activities
that
may
impact
the
integrity
of
a
water
body.
The
1987
Water
Quality
Act
Amendments
to
the
Clean
Water
Act
(
CWA)
explicitly
incorporated
reference
to
antidegradation
policies
in
section
303(
d)(
4)(
B),
which
requires
that
such
antidegradation
requirements
be
satisfied
prior
to
modifying
certain
NPDES
permits
to
include
less
stringent
effluent
limitations
(
this
concept
is
referred
to
as
antibacksliding).
On
March
23,
1995,
EPA
published
the
final
Water
Quality
Guidance
for
the
Great
Lakes
System
(
the
Great
Lakes
Guidance).
The
Great
Lakes
Guidance
includes
an
antidegradation
component
that
is
intended
to
work
in
conjunction
with
the
other
components
of
the
Great
Lakes
Guidance
to
address
the
most
pressing
threats
to
water
quality
in
the
Great
Lakes.
In
order
to
achieve
this
end,
the
focus
of
the
antidegradation
component
is
on
decisions
pertaining
to
new
or
increased
loadings
of
specified
bioaccumulative
chemicals
of
concern
within
the
Great
Lakes
basin.
For
other
types
of
pollutants,
States
and
Tribes
are
required
to
comply
with
the
existing
regulations
at
40
CFR
131.12.
In
the
course
of
establishing
a
framework
for
making
decisions
regarding
increased
loadings
of
bioaccumulative
chemicals
of
concern,
the
Great
Lakes
Guidance
touches
on
a
number
of
issues.
The
Great
Lakes
Guidance
provides
a
procedure
for
identifying
high
quality
waters
on
a
pollutant­
by­
pollutant
basis.
The
Great
Lakes
Guidance
also
defines
how
a
significant
lowering
of
water
quality
will
be
identified
for
purposes
of
determining
whether
or
not
an
antidegradation
review
is
required.
Finally,
the
Great
Lakes
Guidance
includes
implementation
procedures
that
describe
how
an
antidegradation
review
should
be
conducted.
In
all
cases,
the
antidegradation
components
of
the
Great
Lakes
Guidance
are
tailored
to
the
control
of
bioaccumulative
chemicals
of
concern;
other
solutions
may
be
necessitated
by
environmental
threats
faced
elsewhere
in
the
Nation.
EPA's
current
thinking
is
that
on
a
national
scale,
antidegradation
is
not
being
used
as
effectively
as
it
could
be
and
that
a
structured
national
debate
on
antidegradation
is
key
to
improvement.
The
debate
needs
to
identify
deficiencies
in
antidegradation
policy
and
implementation
provisions
and
begin
the
process
of
strengthening
antidegradation
as
a
meaningful
mechanism
to
attain
and
maintain
water
quality
standards.
EPA
invites
comments
and
suggestions
on
the
threetiered
approach
currently
in
use
and
described
below,
as
well
as
possible
other
approaches
to
more
effectively
accomplish
the
intent
of
the
antidegradation
requirements.
As
part
of
the
``
Clean
Water
Action
Plan''
announced
on
February
14,
1998
by
the
Administrator
of
EPA
and
the
Secretary
of
Agriculture,
EPA
plans
to
develop
additional
guidance
on
Antidegradation.
The
discussion
below
articulates
current
EPA
thinking
in
several
areas
of
antidegradation.
Elements
of
this
current
EPA
thinking
will
likely
be
incorporated
into
the
Antidegradation
guidance
EPA
develops
under
the
``
Clean
Water
Action
Plan.''

2.
General
Description
of
Antidegradation
An
antidegradation
policy
performs
an
essential
function
as
part
of
the
of
States'
and
Tribes'
water
quality
standards.
Designated
uses
establish
the
water
quality
goals
for
the
water
body,
water
quality
criteria
define
the
minimum
conditions
necessary
to
achieve
the
goals
and
an
antidegradation
policy
specifies
the
framework
to
be
used
in
making
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129
/
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July
7,
1998
/
Proposed
Rules
decisions
regarding
changes
in
water
quality.
The
intent
of
an
antidegradation
policy
is
to
ensure
that
in
all
cases,
at
a
minimum,
water
quality
necessary
to
support
existing
uses
is
maintained
(
tier
1),
that
where
water
quality
is
better
than
the
minimum
level
necessary
to
support
protection
and
propagation
of
fish,
shellfish
and
wildlife,
and
recreation
in
and
on
the
water
(``
fishable/
swimmable''),
that
water
quality
is
also
maintained
and
protected
unless,
through
a
public
process,
some
lowering
of
water
quality
is
deemed
to
be
necessary
to
allow
important
economic
or
social
development
to
occur
(
tier
2),
and
to
identify
water
bodies
of
exceptional
recreational
or
ecological
significance
and
maintain
and
protect
water
quality
in
such
water
bodies
(
tier
3).
Antidegradation
plays
a
critical
role
in
allowing
States
and
Tribes
to
maintain
and
protect
the
finite
public
resource
of
clean
water
and
ensure
that
decisions
to
allow
reductions
in
water
quality
are
made
in
a
public
manner
and
serve
the
public
good.
The
watershed
approach
may
be
a
powerful
tool
to
achieving
antidegradation
goals
(
i.
e.,
maintaining
the
chemical,
physical,
and
biological
integrity
of
the
Nation's
waters).
Many
and
varied
uses
are
made
of
the
Nation's
waters
and
in
some
cases,
these
uses
conflict.
The
ability
of
particular
waters
to
accommodate
all
uses
is
limited.
High
quality
surface
waters
are
an
important
and
finite
resource
whose
availability
affects
the
health,
welfare,
and
economic
well­
being
of
all
the
citizens
of
the
United
States.
When
operating
properly,
the
antidegradation
policies
of
States
and
Tribes
ensure
that
water
quality
is
conserved
where
possible
and
lowered
only
when
necessary,
and
that
those
affected
by
the
lowering
of
water
quality
have
a
say
in
the
final
decision.
As
a
result,
antidegradation
policies
are
well­
suited
to
assist
States,
Tribes
and
local
communities
in
establishing
and
achieving
watershed
goals.
Sensitive
or
highly
valued
water
bodies
can
be
identified
and
protected
from
degradation
through
outstanding
national
resource
water
(
ONRW)
or
related
designations.
In
other
water
bodies,
where
water
quality
is
better
than
the
minimum
necessary
to
support
fish
and
aquatic
life
and
recreation,
water
quality
should
be
maintained
unless
there
is
a
demonstrated
need
to
lower
water
quality.
Consistent
with
the
watershed
approach
and
communitybased
environmental
management,
States'
and
Tribes'
antidegradation
policies
and
procedures
can
be
a
basis
for
a
systematic
and
accessible
planning
process
that
protects
against
development
having
negative
impacts
on
water
quality.
Additional
authorities
exist
at
the
local
level
beyond
State,
Tribal
and
federal
authorities
which
may
allow
additional
protections
to
be
put
in
place
in
accordance
with
the
watershed
management
plan.
The
water
quality
standards
regulation
requires
each
State
and
authorized
Tribe
to
adopt,
as
part
of
its
water
quality
standards,
an
antidegradation
policy
consistent
with
40
CFR
131.12
and
identify
implementation
methods
for
such
a
policy.
This
antidegradation
policy
provides
a
multi­
level
approach
for
the
protection
of
water
quality
and
applies
to
both
point
and
non­
point
source
activities.
The
level
of
protection
that
is
provided
to
a
specific
segment
depends
upon
a
number
of
factors
(
e.
g.,
a
key
determinant
is
whether
existing
water
quality
is
found
to
exceed
levels
necessary
to
support
``
fishable/
swimmable''
uses).
Antidegradation
requirements
are
typically
triggered
when
an
activity
is
proposed
that
may
have
some
effect
on
existing
water
quality.
Such
activities
are
reviewed
to
determine,
based
on
the
level
of
antidegradation
protection
afforded
to
the
affected
water
body
segment,
whether
the
proposed
activity
can
be
authorized.
``
Antidegradation
reviews''
under
all
three
tiers
of
antidegradation
should
be
documented
and
subjected
to
public
review
and
comment
(
e.
g.,
as
part
of
the
public
review
of
the
water
quality
certification,
NPDES
permit,
or
other
regulatory
action).
Identifying
the
universe
of
activities
that
trigger
antidegradation
requirements
is
a
fundamental
and
often
controversial
issue
because
of
the
number
and
variety
of
activities
that
can
affect
water
quality.
Clearly,
a
wide
range
of
activities
that
affect
water
quality
may
be
subject
to
antidegradation
requirements,
and
States
and
Tribes
have
considerable
flexibility
in
applying
antidegradation
policies.
The
federal
antidegradation
requirements
do
not
create,
nor
were
they
intended
to
create,
State
or
Tribal
regulatory
authority
over
otherwise
unregulated
activities.
It
is
the
position
of
EPA
that,
at
a
minimum,
States
and
authorized
Tribes
must
apply
antidegradation
requirements
to
activities
that
are
``
regulated''
under
State,
Tribal,
or
federal
law
(
i.
e.,
any
activity
that
requires
a
permit
or
a
water
quality
certification
pursuant
to
State,
Tribal
or
federal
law,
such
as
CWA
§
402
NPDES
permits
or
CWA
§
404
dredge
and
fill
permits,
any
activity
requiring
a
CWA
§
401
certification,
any
activity
subject
to
State
or
Tribal
nonpoint
source
control
requirements
or
regulations,
and
any
activity
which
is
otherwise
subject
to
State
or
Tribal
regulations
that
specify
that
water
quality
standards
are
applicable).
Where
a
State
or
Tribe
wishes
to
require
antidegradation
reviews
for
activities
that
are
not
currently
``
regulated''
under
this
definition,
EPA
recommends
that
a
complete
discussion
of
the
activities
requiring
an
antidegradation
review
be
included
in
the
State
or
Tribal
water
quality
standards
or
other
State
or
Tribal
regulation.
Although
States
and
authorized
Tribes
have
discretion
to
apply
antidegradation
requirements
more
broadly
than
minimally
required,
application
of
antidegradation
requirements
to
activities
that
are
otherwise
unregulated
under
State,
Tribal,
and
federal
water
law
is
not
required
by
the
federal
water
quality
standards
regulation.
EPA's
current
thinking
is
that
antidegradation
principles
can
and
should
be
considered
in
connection
with
a
number
of
activities
even
where
application
of
the
antidegradation
review
requirements
is
not
explicitly
required
by
the
regulation.
EPA
is
interested
in
identifying
ways
to
better
implement
antidegradation,
especially
for
activities
such
as
urban
and
agricultural
run­
off.
As
part
of
general
planning
for
development
that
is
likely
to
affect
surface
water
quality,
it
makes
sense
to
consider
existing
ambient
water
quality
and
evaluate
available
means
to
protect
that
water
quality.
Thus,
although
a
State
or
Tribe
may
not
require
a
formal
antidegradation
review
for
a
particular
activity
(
e.
g.,
an
unregulated
nonpoint
source),
there
may
still
be
value
in
applying
the
antidegradation
principles
in
an
analysis
of
potential
environmental
impacts.
In
sum,
EPA's
current
thinking
is
that
the
antidegradation
policy
is
significantly
underused
as
a
tool
to
attain
and
maintain
water
quality
and
plan
for
and
channel
important
economic
and
social
development
that
can
impact
water
quality.
EPA
believes
this
is
especially
true
for
nonpoint
source
run­
off.
This
ANPRM
provides
an
opportunity
to
identify
and
evaluate
options
for
clarifying
and
strengthening
antidegradation
policy
and
its
implementation.
States
and
authorized
Tribes
often
submit
implementation
procedures
to
EPA
for
review
as
part
of
the
water
quality
standards
triennial
review
required
by
section
303(
c)
of
the
Act.
This
enables
EPA
to
determine
if
the
implementation
procedures
fulfill
the
requirements
of
the
antidegradation
36781
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
policy.
The
antidegradation
policy
itself
is
expressly
required
by
40
CFR
131.20(
c)
to
be
submitted
to
EPA
for
review.
EPA's
longstanding
policy
is
that
the
implementation
procedure
should
also
be
submitted
to
EPA
for
review.
Often,
however,
implementation
procedures
are
not
submitted
to
EPA.
EPA's
current
thinking
is
that
an
important
change
to
the
regulation
would
be
to
clarify
under
40
CFR
section
131.20(
c)
that
State
and
Tribal
antidegradation
implementation
procedures
(
in
addition
to
the
policy)
must
be
included
in
the
submittal
of
a
State's
or
Tribe's
water
quality
standards.
Such
a
change
could
establish
the
foundation
for
additional
substantive
changes
to
the
regulation
concerning
national
norms
for
antidegradation
implementation
procedures.
A
State's
or
Tribe's
implementation
method
is
on
occasion
so
constructed
as
to
essentially
set
aside
the
intent
of
the
antidegradation
policy.
EPA
has
disapproved
this
aspect
of
State
standards
where
the
implementation
procedure
is
inconsistent
with
the
policy.
Revising
the
regulation
to
specify
requirements
addressing
the
content
of
such
implementation
procedures
(
e.
g.,
a
core
set
of
issues
that
must
be
resolved),
and
clarifying
that
implementation
procedures
must
be
included
in
the
submittal
package,
may
help
to
clarify
EPA's
role
in
determining
whether
State
or
Tribal
antidegradation
implementation
procedures
adequately
uphold
and
implement
the
State's
or
Tribe's
antidegradation
policy.
In
addition,
specifying
in
the
regulation
the
basic
elements
of
an
implementation
procedure
could
serve
to
better
establish
national
norms
for
State
and
tribal
antidegradation
procedures.
EPA
is
considering
whether
it
would
assist
States
and
Tribes
if
the
regulation
were
amended
to
identify
the
basic
elements
that
must
be
included
in
an
antidegradation
implementation
method.
Guidance
on
developing
antidegradation
implementation
methods
is
provided
through
EPA's
Regional
Offices.
EPA
has
not
issued
national
guidance
on
these
implementation
methods
and
is
interested
in
comments
on
whether
national
guidance
on
antidegradation
implementation
methods
is
needed,
and
whether
elements
of
such
guidance
should
be
referenced
or
included
in
the
Regulation.

Request
for
Comments
on
General
Antidegradation
Policy
EPA
requests
comment
on
the
following
questions:
1.
What
changes
or
clarifications
could
be
made
to
the
current
tiered
approach
to
protecting
waters
under
antidegradation
that
would
streamline
and
enhance
antidegradation
implementation?
2.
Should
the
regulation
be
amended
to
identify
the
basic
elements
that
must
be
included
in
an
antidegradation
implementation
method
and
would
such
changes
assist
States
and
Tribes
in
understanding
the
requirements
and
in
utilizing
the
flexibility
available?
3.
Is
national
guidance
on
antidegradation
implementation
methods
needed
and
should
elements
of
such
guidance
be
referenced
or
included
in
the
Regulation?

3.
40
CFR
131.12
(
a)(
1)
``
tier
1''
Section
131.12
(
a)(
1)
of
the
antidegradation
policy
contained
in
the
water
quality
standards
regulation
requires
that
existing
uses
and
the
water
quality
necessary
to
protect
them
be
maintained
and
protected.
This
provision,
in
effect,
establishes
the
floor
of
water
quality
in
the
U.
S.
It
also
protects
the
environment
where
the
existing
use
of
a
water
body
happens
to
be
better
than
the
use
designated
by
the
State
or
Tribe.
An
existing
use
as
defined
in
40
CFR
131.3
can
be
established
by
demonstrating
that
a
use
has
actually
occurred
since
November
28,
1975,
or
that
the
water
quality
is
suitable
to
allow
such
uses
to
occur,
whether
or
not
such
uses
are
designated
uses
for
the
water
body
in
question.
All
waters
of
the
U.
S.
are
subject
to
tier
1
protection.
In
general,
waters
that
are
subject
to
only
tier
1
antidegradation
policies
are
those
water
bodies
that
do
not
exceed
the
CWA
Section
101(
a)(
2)
goals,
or
do
not
have
assimilative
capacity
to
receive
additional
quantities
of
a
pollutant(
s)
without
jeopardizing
the
existing
use.
Existing
uses
and
additional
issues
related
to
defining
them
and
their
relationship
to
designated
uses
are
further
discussed
in
section
III(
B)(
3)
of
this
document.
Antidegradation
policies
are
generally
implemented
for
tier
1
by
a
review
procedure
that
evaluates
any
discharge
to
determine
whether
it
would
impair
an
existing
use.
Prior
to
authorizing
any
proposed
activity,
a
State
or
authorized
Tribe
shall
ensure
that
water
quality
sufficient
to
protect
existing
uses
fully
will
be
achieved.
In
addition
to
ensuring
that
existing
uses
will
be
protected,
the
State
or
Tribe
should
ensure
that
all
existing
uses
are
designated
in
accordance
with
40
CFR
131.10(
i).
a.
Tier
1
Implementation.
In
order
to
implement
tier
1,
a
State
or
Tribe
must
define
what
is
meant
by
the
term
``
existing
in­
stream
water
use''
(
40
CFR
131.12(
a)(
1))
and
must
also
be
able
to
identify
the
level
of
water
quality
that
is
required
to
permit
an
existing
use
to
continue
to
occur.
Section
131.3
defines
existing
uses
as,
``
those
uses
actually
attained
in
the
water
body
on
or
after
November
28,
1975
*
*
*''
Traditionally,
when
establishing
designated
uses,
States
and
Tribes
tend
to
define
uses
in
terms
of
broad
classes,
such
as
warm
water
fishery
or
secondary
contact
recreation.
Inherent
in
each
of
the
broad
use
categories
are
specific
uses
that
may
be
affected
by
a
change
in
water
quality.
For
example,
a
warm
water
fishery
designated
use
may
include
the
existing
use
of
large
mouth
bass
fishery.
Many
people
would
be
upset
if
the
warm
water
fishery
designated
use
was
protected
in
such
a
way
as
to
allow
a
decline
in
the
bass
population.
The
central
question
faced
by
States
and
Tribes
in
determining
whether
or
not
a
proposed
action
will
impact
existing
uses
is
whether
each
specific
use
within
a
use
class
must
be
maintained
(
each
individual
type
of
species),
or
whether
only
the
use
class
itself
must
be
maintained
(
allow
changes
in
species
composition,
but
maintain
a
fishery).
State
and
Tribal
interpretations
of
this
requirement
vary
considerably
and
are
often
tied
to
the
degree
of
precision
the
State
or
Tribe
achieves
in
defining
designated
uses.
Many
States
and
some
Tribes
have
addressed
these
questions
by
using
the
same
degree
of
precision
for
both
designated
and
existing
uses.
EPA's
current
thinking
is
that
this
is
an
acceptable
approach
as
long
as
the
State's
or
Tribe's
designated
uses
and
criteria
applicable
to
those
uses
are
adequate
to
ensure
that
existing
uses
are
maintained
under
the
federal
antidegradation
provisions.
It
would
not
be
acceptable,
for
example,
for
a
state
to
allow
the
loss
of
an
existing
natural
cold
water
community
in
favor
of
a
warm
water
community
because
both
satisfy
the
general
use
designation
of
``
aquatic
life.''
Nor
would
it
be
acceptable
to
allow
shifts
from
existing
pollution
intolerant
communities
to
communities
that
tolerate
degraded
conditions.
The
advantage
of
this
approach
is
that
the
same
criteria
used
to
protect
the
designated
use
can
be
assumed
to
also
protect
the
existing
use.
Under
this
approach,
however,
the
protection
afforded
to
existing
uses
is
limited
by
the
degree
of
refinement
associated
with
the
designated
uses.
States
and
Tribes
that
have
more
specific
designated
uses
(
i.
e.,
including
a
number
of
use
subcategories
can
potentially
provide
more
protection
by
addressing
more
subtle
changes
to
the
existing
use.
States
and
36782
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
Tribes
with
less
specific
designated
uses
would
have
less
precision
associated
with
their
existing
use
protection
scheme.
An
important
tier
1
implementation
issue
concerns
how
a
State
or
Tribe
will
prevent
negative
or
harmful
impacts
to
existing
uses
when
water
quality
criteria
that
have
been
established
to
protect
the
designated
uses
are
not
adequate
to
protect
the
existing
uses.
For
example,
a
regulated
discharge
of
uncontaminated
sediment
may
result
in
significant
negative
or
harmful
impacts
to
aquatic
life
habitat
and
loss
of
aquatic
life
use.
In
such
cases,
where
clean
sediment
or
siltation
criteria
have
not
been
developed
for
the
site,
and
where
the
State
or
Tribe
has
not
established
clear
procedures
to
implement
narrative
criteria
governing
sedimentation,
it
may
be
difficult
to
prohibit
such
loss
of
use,
particularly
where
a
State
or
Tribe
has
not
adopted
biological
criteria.
A
second
example
arises
where
a
proposed
activity
will
result
in
the
discharge
of
a
substance
for
which
numeric
criteria
have
not
been
adopted
by
the
State
or
Tribe,
but
sufficient
data
to
derive
criteria
or
a
numeric
translation
of
the
narrative
criteria
are
available.
Where
a
range
of
numeric
criteria
can
potentially
be
justified
for
the
particular
substance
to
protect
the
designated
and/
or
existing
use,
it
may
be
difficult
or
contentious
for
the
State
or
Tribe
to
derive
effluent
limits
protective
of
the
existing
use.
A
third
example
arises
where
a
proposed
hydrologic
modification
will
result
in
diminished
flow
in
a
water
body
and
create
the
potential
for
loss
of
existing
aquatic
life
use
either
through
increased
temperatures
or
turbidity,
or
loss
of
habitat.
State
and
Tribal
water
quality
criteria
generally
do
not
describe
minimum
acceptable
flows
and
may
not,
by
themselves,
adequately
protect
against
such
loss
of
use.
In
P.
U.
D.
No.
1
of
Jefferson
County
and
City
of
Tacoma
v.
Washington
Department
of
Ecology,
(
114
S.
Ct
1900
(
1994)),
the
Supreme
Court
ruled
that
State
certifications
under
section
401
of
the
CWA
may
include
conditions
to
ensure
compliance
not
only
with
a
State's
water
quality
criteria,
but
also
with
a
State's
designated
uses
or
antidegradation
policy.
The
Court
concluded
that
a
State
could
require,
in
this
case,
a
dam
to
be
designed
and
operated
in
such
a
way
as
to
maintain
stream
flows
necessary
to
protect
the
designated
use
of
a
stream.
While
this
specific
case
had
to
do
with
a
dam
and
stream
flows
necessary
to
protect
a
use,
it
should
be
noted
that
the
opinion
applies
more
broadly
than
to
just
flow
and
that
in
addition
to
maintenance
of
in­
stream
flows
to
protect
water
quality
standards,
States
may
also
apply
any
other
parameter
that
may
not
be
specifically
identified
in
the
State's
standards.
EPA
notes
that
where
such
implementation
methods
are
spelled
out,
as
a
practical
matter,
they
may
be
more
easily
implemented.
(
See
related
discussion
in
Section
III.
B.
on
uses).
EPA
believes
that
tier
1
methods
or
policies
for
addressing
situations
such
as
those
described
above
may
need
to
be
included
in
an
antidegradation
implementation
procedure.

Request
for
Comments
on
Antidegradation
Tier
1
EPA
specifically
requests
public
comment
on
the
following
questions:
1.
Do
State
and
Tribal
programs
under
the
existing
regulation
do
an
adequate
job
of
protecting
existing
in­
stream
uses?
2.
Is
a
more
detailed
definition
of
``
existing
in­
stream
water
uses''
needed
in
the
regulation?
Should
it
be
the
same
as
``
existing
uses?'
3.
Should
the
regulation
define
what
constitutes
loss
of
an
existing
in­
stream
water
use?
4.
Should
a
clear
approach
to
maintaining
and
protecting
existing
uses
that
may
not
be
adequately
protected
by
strict
application
of
water
quality
criteria
be
a
required
element
of
an
antidegradation
implementation
procedure?
5.
Should
the
regulation
specify
under
antidegradation
that
protection
of
both
existing
and
designated
uses
is
required?

4.
40
CFR
131.12
(
a)(
2)
``
tier
2''

``
Tier
2''
(
§
131.12(
a)(
2))
antidegradation
policies
are
intended
to
protect
the
waters
in
which
water
quality
is
better
than
necessary
to
support
propagation
of
fish,
shellfish
and
wildlife,
and
recreation
in
and
on
the
water
body.
These
are
called
high
quality
waters.
For
such
high
quality
waters,
existing
water
quality
must
be
maintained
and
protected
unless
it
is
demonstrated
that
a
lowering
of
water
quality
is
necessary
to
accommodate
important
economic
or
social
development.
The
protection
of
high
quality
waters
envisioned
by
the
regulation
encourages
a
systematic,
public
decision
making
process
for
determining
whether
or
not
to
allow
limited
deterioration
of
water
quality
in
high
quality
waters.
a.
Identification
of
``
High
Quality''
Waters.
Identifying
waters
that
are
``
high
quality''
and
subject
to
tier
2
protection
is
an
important
antidegradation
issue.
The
water
quality
standards
regulation
requires
application
of
tier
2
requirements
``
where
the
quality
of
the
waters
exceed
levels
necessary
to
support
propagation
of
fish,
shellfish,
and
wildlife
and
recreation
in
and
on
the
water.''
However,
the
regulation
does
not
include
specific
guidelines
for
identifying
high
quality
waters.
Various
EPA
guidance
documents,
including
those
issued
by
EPA's
Regional
offices,
make
a
variety
of
suggestions
concerning
approaches
to
defining
tier
2
waters.
Not
surprisingly,
States
and
Tribes
have
developed
various
ways
to
identify
tier
2
waters.
Existing
approaches
for
identifying
high
quality
waters
fall
into
two
basic
categories:
(
1)
pollutant­
by­
pollutant
approaches,
and
(
2)
water
body­
bywater
body
approaches.
States
and
Tribes
following
the
first
approach
determine
whether
water
quality
is
better
than
applicable
criteria
for
specific
pollutants
that
would
be
affected
by
the
proposed
activity.
Thus,
available
assimilative
capacity
for
any
given
pollutant
is
always
subject
to
tier
2
protection,
regardless
of
whether
the
criteria
for
other
pollutants
are
satisfied.
Such
determinations
are
made
at
the
time
of
the
antidegradation
review
(
i.
e.,
as
activities
that
may
degrade
water
quality
are
proposed).
States
and
Tribes
following
the
second
approach
weigh
a
variety
of
factors
to
judge
a
water
body
segment's
overall
quality.
Such
determinations
may
be
made
prior
to
the
antidegradation
review
(
i.
e.,
the
State
or
Tribe
may
assign
``
high
quality''
designations
in
the
State
or
Tribal
standards),
or
during
the
course
of
the
antidegradation
review.
Under
this
water
body­
by­
water
body
approach,
sometimes
referred
to
as
the
``
designational''
approach,
assimilative
capacity
for
a
given
pollutant
may
not
be
subject
to
tier
2
protection
if,
overall,
the
segment
is
not
deemed
``
high
quality.''
There
are
advantages
and
disadvantages
to
each
approach.
EPA's
current
thinking
is
that
neither
approach
is
clearly
superior
and
that
either,
when
properly
implemented,
is
acceptable.
EPA
has
approved
both
approaches
in
State
standards.
Some
States
and
Tribes
have
found
the
pollutant­
by­
pollutant
approach
to
be
easier
to
implement
because
the
need
for
an
overall
assessment
considering
various
factors
is
avoided.
Also,
decisions
are
driven
strictly
by
water
column
data
(
i.
e.,
rather
than
judgments
concerning
a
segment's
overall
value
or
quality)
and
thus
may
be
less
susceptible
to
challenge.
The
pollutantby
pollutant
approach
may
result
in
more
waters
receiving
some
degree
of
tier
2
protection
because
it
would
cover
36783
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Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
waters
that
are
clearly
not
attaining
goal
uses
(
i.
e.,
waters
which
are
not
supporting
``
fishable/
swimmable''
goal
uses
but
that
possess
assimilative
capacity
for
one
or
more
pollutant).
The
water
body­
by­
water
body
approach,
on
the
other
hand,
allows
for
a
weighted
assessment
of
chemical,
physical,
biological,
and
other
information
(
e.
g.,
unique
ecological
or
scenic
attributes).
In
this
regard,
the
water
body­
by­
water
body
approach
may
be
better
suited
to
EPA's
stated
vision
for
the
water
quality
standards
program:
refined
designated
uses
with
tailored
criteria,
complete
information
on
uses
and
use
attainability,
and
clear
national
norms.
The
water
body­
bywater
body
approach
preserves
water
quality
even
if
criteria
for
certain
pollutants
are
not
attained
or
if
criteria
for
certain
uses
may
be
limited,
such
as
fish
consumption.
This
approach
also
allows
for
the
high
quality
water
decision
to
be
made
in
advance
of
the
antidegradation
review
(
and
included
in
the
water
quality
standards
for
the
segment),
which
may
facilitate
implementation.
A
water
body­
by­
water
body
approach
also
allows
States
and
Tribes
to
focus
limited
resources
on
protecting
higher­
value
State
or
Tribal
waters.
The
water
body­
by­
water
body
approach
can
also
distinguish
between
high
quality
waters
and
high
water
quality
and
preserve
high
quality
waters
on
the
basis
of
physical
and
biological
attributes,
rather
than
high
water
quality
attributes
alone.
However,
the
flexibility
of
the
water
body­
by­
water
body
approach
is
also
its
principal
disadvantage
where
a
State
or
Tribe
does
not
develop
inclusive
qualification
criteria.
For
example,
where
a
State's
or
Tribe's
implementation
guidelines
define
a
narrow
universe
of
waters,
many
deserving
high
quality
waters
may
not
receive
tier
2
protection.
Thus
water
quality
may
actually
decrease
in
the
waters
not
classified
for
tier
2
protection
without
a
public
review
of
the
development
decision.
Also,
a
potential
problem
can
arise
if
the
process
of
identifying
high
quality
waters
becomes
so
complicated,
resource­
intensive,
and
data­
intensive
that
the
primary
purpose
of
tier
2
(
i.
e.,
seeking
to
maintain
and
protect
existing
quality
by
identifying
whether
there
are
reasonable
lessdegrading
or
non­
degrading
alternatives)
is
not
adequately
accomplished.
In
other
words,
the
limited
resources
available
for
water
quality
protection
could
be
spent
on
the
identification
process
at
the
expense
of
analysis
of
the
necessity
for
degradation.
b.
Tier
2
Implementation.
The
current
regulation
provides
a
great
deal
of
flexibility
to
States
and
Tribes
in
implementing
tier
2
requirements.
Some
States
and
Tribes
devote
little
effort
to
implementing
their
tier
2
requirements,
some
States
and
Tribes
apply
tier
2
requirements
in
an
inconsistent
or
infrequent
manner,
and
other
States
and
Tribes
have
active
programs
that
routinely
and
consistently
implement
tier
2.
In
general,
those
States
and
Tribes
that
actively
implement
their
tier
2
requirements
do
so
by
conducting
an
antidegradation
review
to
determine
whether
proposed
activities
that
might
affect
water
quality
may
be
authorized.
EPA's
current
sense
is
that
the
antidegradation
policy,
in
reality,
has
little
effect
on
decisions
related
to
surface
water
quality
unless
the
State
or
Tribe
adopts
an
implementation
procedure
and
uses
it.
EPA
currently
reviews
all
State
and
Tribal
water
quality
standards
at
the
time
of
adoption/
revision
to
ensure
they
establish
a
clear
approach
to
implementation.
A
brief
discussion
of
a
number
of
the
major
implementation
issues
is
presented
below.
i.
Triggers
for
tier
2
Review.
Although
not
discussed
in
40
CFR
131.12
of
the
water
quality
standards
regulation,
State
and
on
occasion
Tribal
tier
2
implementation
procedures
often
include
guidelines
which
are
used
to
determine
when
the
water
quality
degradation
that
will
result
from
a
proposed
activity
is
significant
enough
to
warrant
further
antidegradation
review.
Where
the
degradation
is
not
significant,
the
antidegradation
review
is
typically
terminated
for
that
proposed
activity.
The
significance
evaluation
is
usually
conducted
on
a
pollutant­
bypollutant
basis,
even
where
a
water
body­
by­
water
body
approach
is
used
to
identify
high
quality
waters,
and
significant
degradation
for
any
one
pollutant
triggers
further
review
for
that
pollutant.
Applying
antidegradation
requirements
only
to
activities
that
will
result
in
significant
degradation
is
a
useful
approach
that
allows
States
and
Tribes
to
focus
limited
resources
where
they
may
result
in
the
greatest
environmental
protection.
However,
there
is
a
great
deal
of
variation
in
how
States
and
Tribes
define
significant
degradation.
Significance
tests
range
from
simple
to
complex,
involve
qualitative
or
quantitative
measures
or
both,
and
may
vary
depending
upon
the
type
of
pollutant
(
e.
g.,
the
approach
may
be
different
for
highly
toxic
or
bioaccumulative
pollutants).
In
some
cases,
States
have
also
created
categorical
exemptions
from
tier
2
review
(
e.
g.,
they
have
exempted
entire
categories
of
activities
from
antidegradation
reviews
based
on
a
general
finding
that
such
activities
do
not
result
in
significant
degradation).
States
or
Tribes
that
define
a
high
threshold
of
significance
may
be
unduly
restricting
the
number
of
proposed
activities
that
are
subject
to
a
full
antidegradation
review.
Further
the
approach
currently
used
by
some
States
may
not
adequately
prevent
cumulative
water
quality
degradation
on
a
watershed
scale.
The
current
regulation
does
not
specify
a
significance
threshold
below
which
an
antidegradation
review
would
not
be
required.
EPA's
current
thinking
is
that
a
clear
national
norm
regarding
this
``
significance
test''
is
necessary
and
should
be
developed
and
established
in
either
the
regulation
or
national
guidance.
A
related
issue
concerns
whether
tier
2
should
be
applied
to
pollutants
where
numeric
criteria
have
not
been
adopted.
For
example,
where
there
is
a
proposed
discharge
of
a
pollutant
to
a
``
high
quality''
segment,
and
the
background
concentration
of
the
pollutant
is
at
or
near
zero
in
the
water
body,
should
significant
degradation
be
evaluated
and
should
it
be
evaluated
any
differently
where
numeric
criteria
for
the
pollutant
have
not
been
adopted?
For
example,
where
a
State
or
Tribe
lacks
numeric
criteria
for
nutrients
such
as
nitrogen
and
phosphorus
(
a
common
occurrence),
increased
discharges
of
these
nutrients
can
be
expected
to
result
in
changes
in
plant
life
or
species
diversity.
If
the
State
or
Tribe
relies
entirely
on
a
pollutant
loadings
comparison
to
numeric
criteria
for
the
tier
2
evaluation,
new
loadings
of
nutrients
may
not
even
be
evaluated
under
tier
2.
EPA's
sense
is
that,
in
practice,
the
current
tier
2
requirements
tend
to
be
used
to
protect
high
quality
waters
only
where
such
high
quality
supports
fishing
and
swimming
uses.
However,
limiting
tier
2
protection
to
assimilative
capacity
associated
with
only
fishing
and
swimming
uses
means
that
the
protection
afforded
by
tier
2
can
end
up
being
narrower
than
intended.
For
example,
where
a
water
has
unique
ecological
significance
(
e.
g.,
acid
bog
or
thermal
spring)
not
captured
by
``
fishable/
swimmable,''
the
State
or
Tribe
may
not
believe
it
is
appropriate
to
designate
the
water
as
high
quality
under
tier
2.
In
this
case,
the
unique
ecological
characteristic
would
warrant
protection
as
an
existing
use.
The
State
or
Tribe
also
has
the
option
of
designating
the
water
ONRW,
yet,
as
discussed
elsewhere
in
this
section,
EPA
believes
that
many
States
and
Tribes
are
not
inclined
to
designate
waters
ONRW.
The
result
in
this
example
is
that
a
water
with
unique
36784
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
ecological
significance
that
may
warrant
a
relatively
high
level
of
protection,
falls
through
the
crack
between
tiers
1
and
2
where
the
State
or
Tribe
interprets
the
level
of
protection
afforded
by
those
tiers
too
narrowly.
ii.
``
Necessary''
Lowering
of
Water
Quality.
The
water
quality
standards
regulation
requires
that
the
water
quality
of
high
quality
waters
not
be
lowered
unless
the
State
or
Tribe
determines
that
such
degradation
is
necessary
to
accommodate
important
social
and
economic
development.
Given
the
variety
of
available
engineering
approaches
to
pollution
control
and
the
emerging
importance
of
pollution
prevention,
the
finding
of
necessity
is
among
the
most
important
and
useful
aspects
of
an
antidegradation
program
and
potentially
an
extremely
useful
tool
in
the
context
of
watershed
planning.
An
approach
that
has
been
recommended
by
EPA
is
to
require
the
proponent
of
the
proposed
activity
to
develop
an
analysis
of
pollution
control/
pollution
prevention
alternatives.
In
conducting
its
antidegradation
review,
the
State
or
Tribe
then
ensures
that
all
feasible
alternatives
to
allowing
the
degradation
have
been
adequately
evaluated,
and
that
the
least
degrading
reasonable
alternative
is
implemented.
Also,
note
that
where
less­
degrading
alternatives
are
more
costly
than
the
pollution
controls
associated
with
the
proposal,
the
State
or
Tribe
should
determine
whether
the
costs
of
the
less­
degrading
alternative
are
reasonable.
EPA
believes
that
such
an
alternatives
analysis
approach
can
be
an
effective
tool
for
maintaining
and
protecting
existing
assimilative
capacity.
EPA's
current
thinking
is
that
specifying
what
would
constitute
an
acceptable
alternatives
analysis
in
the
regulation,
could
result
in
the
addition
of
substance
and
rigor
to
the
``
tier
2''
antidegradation
reviews
conducted
by
States
and
Tribes.
iii.
Identification
of
``
Important''
Social
or
Economic
Activities.
Another
task
that
must
be
completed
as
part
of
an
antidegradation
review
is
to
evaluate
whether
a
proposed
activity
that
will
result
in
degradation
is
necessary
to
accommodate
important
social
or
economic
development
in
the
area
in
which
the
waters
are
located.
(
40
CFR
131.12(
a)(
2))
The
significance
of
determining
if
an
activity
will
provide
for
important
social
or
economic
benefit
is
that,
absent
important
social
or
economic
benefit,
degradation
under
tier
2
must
not
be
allowed.
Factors
that
may
be
addressed
in
such
an
evaluation
include:
(
a)
employment
(
i.
e.,
increasing,
maintaining,
or
avoiding
a
reduction
in
employment),
(
b)
increased
production,
(
c)
improved
community
tax
base,
(
d)
housing,
and
(
e)
correction
of
an
environmental
or
public
health
problem.
Some
States
or
Tribes
have
addressed
this
issue
by
requiring
the
applicant
to
bear
the
burden
of
demonstrating
the
social
and
economic
importance
of
the
proposed
activity.
However,
approaches
for
evaluating
social
and
economic
importance
vary
widely.
EPA
published
Interim
Economic
Guidance
for
Water
Quality
Standards:
Workbook,
Appendix
M
to
the
``
Water
quality
Standards
Handbook
 
Second
Edition''
in
March
1995
(
EPA
 
823
 
B
 
95
 
002,
March
1995).
This
guidance
specifically
addresses
the
determination
of
social
and
economic
importance
in
the
context
of
a
tier
2
antidegradation
review
and
should
be
useful
to
States
and
Tribes
in
determining
the
relative
economic
consequences
of
various
development
proposals
and
their
relationship
to
water
quality
standards.
EPA's
current
thinking
is
that
determining
the
social
and
economic
importance
of
a
proposed
activity
is
an
important
public
question
best
addressed
by
State,
Tribal
or
local
interests,
perhaps
as
part
of
the
development
of
a
basin
plan.
iv.
Tier
2
and
Identification
of
Waters
under
CWA
Section
303(
d).
Section
303(
d)
of
the
Clean
Water
Act
and
EPA
regulations
require
States
to
develop
lists
of
waters
that
do
not
meet
State
water
quality
standards,
even
after
point
sources
of
pollution
install
the
minimum
required
levels
of
pollution
control
technology.
Section
303(
d)
lists
must
be
submitted
to
EPA
every
two
years.
The
waters
on
the
lists
are
called
water
quality­
limited
waters
and
are
defined
in
EPA
regulations
as
waters
``
where
it
is
known
that
water
quality
does
not
meet
applicable
water
quality
standards,
and/
or
is
not
expected
to
meet
applicable
water
quality
standards,
even
after
the
application
of
the
technology­
based
effluent
limitations
required
by
section
301(
b)
and
306
of
the
[
Clean
Water]
Act.''
40
CFR
130.2(
j).
States
are
then
required
to
develop
total
maximum
daily
loads
(
TMDLs)
for
water
quality­
limited
waters.
EPA's
current
policy
is
that
States
include
waters
on
section
303(
d)
lists
if
applicable
water
quality
standards
are
not
met
or
are
not
expected
to
be
met
by
the
next
list
submission
deadline,
i.
e.,
within
two
years
(
see
memorandum
from
Robert
Wayland,
Director
Office
of
Wetlands,
Oceans
and
Watersheds,
to
Water
Management
Division
Directors,
Regions
I
 
X,
Directors
Great
Water
Body
Programs
and
Water
Quality
Branch
Chiefs,
Regions
I
 
X,
Subject:
National
Clarifying
Guidance
for
1998
State
and
Territory
Section
303(
d)
Listing
Decisions,
August
27,
1997).
In
determining
whether
to
list
waters,
States
should
consider
all
aspects
of
applicable
water
quality
standards,
including
narrative
and
numeric
criteria,
designated
uses,
and
antidegradation
policies.
EPA
is
currently
discussing
with
stakeholders
possible
changes
and
clarifications
to
the
water
body
listing
regulations
and
guidance
under
section
303(
d)
of
the
Act.
Changes
and/
or
clarifications
could
include
a
statement
in
the
regulation,
or
a
clarification,
that
identifies
existing
tier
2
antidegradation
analyses
and
decisions
as
``
existing
and
readily
available
water
quality­
related
data
and
information''
that
must
be
considered
under
40
CFR
130.7(
b)(
5)
when
deciding
whether
to
place
a
water
body
on
a
section
303(
d)
list.
Information
from
existing
antidegradation
tier
2
reviews
on
assimilative
capacity
for
particular
water
bodies
could
be
used
to
determine
whether
a
water
body
is
likely
to
not
meet
water
quality
standards
in
the
near
future
and
thus
required
to
be
included
on
the
section
303(
d)
list.
In
addition,
EPA
could
amend
the
existing
antidegradation
regulations
to
direct
States
and
Tribes
to
consider
the
303(
d)
listing
status
of
a
water
body,
and
the
information
supporting
that
status,
when
determining
whether
a
proposed
activity
that
is
expected
to
degrade
water
quality
in
that
water
body
can
be
authorized
under
tier
2
of
the
State's
or
Tribe's
antidegradation
provisions.
v.
Achieving
all
cost­
effective
and
reasonable
best
management
practices
for
nonpoint
sources.
This
implementation
issue
arises
from
one
sentence
that
is
included
in
the
federal
antidegradation
policy
at
40
CFR
131.12(
a)(
2):

Further,
the
State
shall
assure
that
there
shall
be
achieved
the
highest
statutory
and
regulatory
requirements
for
all
new
and
existing
point
sources
and
all
cost­
effective
and
reasonable
best
management
practices
for
nonpoint
source
control.

This
sentence
has
been
somewhat
controversial
over
the
years
because
it
could
be
interpreted
to
require
a
State
or
Tribe
to
include,
in
its
water
quality
standards,
a
provision
requiring
adoption
of
authority
for,
as
well
as
achievement
of,
best
management
practices
(
BMPs)
for
nonpoint
sources
prior
to
allowing
degradation
of
high
quality
waters.
EPA
has
interpreted
131.12(
a)(
2)
as
not
requiring
a
State
or
Tribe
to
establish
BMP
requirements
for
nonpoint
sources
where
such
BMP
requirements
do
not
exist.
As
EPA
clarified
in
a
February
22,
1994
guidance
memorandum,
State
and
36785
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
Tribal
antidegradation
rules
need
only
include
provisions
to
assure
achievement
of
BMPs
that
are
required
under
State
or
Tribal
nonpoint
source
control
laws
or
regulations.
(
Memorandum
from
Tudor
T.
Davies,
Director
EPA
Office
of
Science
and
Technology
to
EPA
Water
Management
Division
Directors,
Regions
I
 
X,
Subject:
Interpretation
of
Federal
Antidegradation
Regulatory
Requirement,
February
22,
1994)
Thus,
States
and
Tribes
that
have
adopted
nonpoint
source
controls
must
assure
that
such
controls
are
properly
implemented
before
authorization
is
granted
to
allow
point
source
degradation
of
water
quality.
EPA's
current
thinking
is
that
the
term
``
all
cost­
effective
and
reasonable
best
management
practices
for
nonpoint
source
control''
in
40
CFR
131.12(
a)(
2)
would
be
more
effective
if
read
more
broadly.
In
other
words,
the
term
could
include
nonpoint
source
best
management
practices
established
through
Federal,
State,
Tribal,
and
local
authorities
and
programs
that
address
activities
on
the
land
or
water
that
create
or
exacerbate
impacts
to
surface
waters.
This
construction
is
consistent
with
EPA's
Total
Maximum
Daily
Load
(
TMDL)
program
under
Section
303(
d)
of
the
Clean
Water
Act.
There,
EPA's
current
policy
is
that
in
achieving
pollutant
load
reductions
from
nonpoint
sources,
EPA
and
States
should
work
in
partnership,
using
all
available
Federal,
State,
and
local
authorities
and
programs.
As
EPA
stated
in
an
August
1997
TMDL
guidance
memorandum,
States
are
expected
to
achieve
nonpoint
source
pollutant
load
reductions
through
such
authorities
and
programs,
including
non­
regulatory,
regulatory,
or
incentive­
based
programs.
EPA
is
considering
applying
the
same
test
to
§
131.12(
a)(
2).
In
addition,
EPA's
current
thinking
is
that
it
may
be
time
to
begin
to
more
actively
ensure
implementation
of
this
requirement:
to
implement
cost
effective
and
reasonable
best
management
practices
for
nonpoint
source
control
before
allowing
lowering
of
water
quality
in
a
water
body.
One
way
to
do
this
would
be
to
specify
that
State
and
Tribal
antidegradation
implementation
procedures
include
a
step
under
which
States
and
Tribes
inventory
their
nonpoint
source
authorities
and
programs,
and,
as
part
of
each
antidegradation
review,
include
in
the
record
documentation
on
how
those
authorities
and
programs
were
applied
to
activities
in
a
watershed
in
which
additional
loadings
subject
to
an
antidegradation
review
have
been
considered.
Emphasizing
this
requirement
by
specifying
it
as
a
required
aspect
of
a
State
or
Tribal
antidegradation
implementation
procedure,
in
EPA's
view,
would
facilitate
use
of
antidegradation
policy
as
a
tool
to
ensure
that
nonpoint
sources
are
controlled
where
possible
in
accordance
with
water
quality
standards,
before
any
additional
assimilative
capacity
in
a
water
body
can
be
allocated
to
an
activity.
EPA
is
interested
in
comment
on
this
current
thinking
and
specifically
on
whether
it
would
be
helpful
to
revise
the
regulation
to
clarify
the
relationship
between
nonpoint
source
controls
and
tier
2
antidegradation
requirements.
In
summary,
numerous
stakeholders
have
commented
to
EPA
that
antidegradation
reviews
are
conducted
inconsistently
across
the
country
and
that
EPA
should
attempt
to
improve
the
national
consistency
of
such
reviews.
EPA
is
interested
in
comment
on
the
appropriate
balance
between
national
consistency
and
State
and
Tribal
flexibility
in
the
implementation
of
the
tier
2
provision
and
on
what
changes
may
be
needed
to
the
regulation
or
EPA
policy
or
guidance
to
ensure
that
the
tier
2
provision
is
implemented
in
a
nationally
consistent
manner
that
is
consistent
with
the
intent
of
the
antidegradation
provision,
and
whether
a
consistent
approach
should
be
the
goal
of
States'
and
Tribes'
watershed
programs.

Request
for
Comments
on
Antidegradation
Tier
2
EPA
requests
comment
on
the
following
questions:
1.
Does
the
existing
requirement
to
apply
tier
2
``
where
the
quality
of
the
waters
exceed
levels
necessary
to
support
propagation
of
fish,
shellfish,
and
wildlife
and
recreation
in
and
on
the
water''
while
at
the
same
time
``
protecting
existing
uses
fully''
need
to
be
clarified
with
respect
to
which
waters
are
afforded
tier
2
antidegradation
protection,
and
if
so,
should
the
Agency
clarify
the
requirement
with
additional
guidance,
or
with
revisions
to
the
regulation?
2.
What
factors
should
be
considered
in
identifying
``
high
quality''
waters?
Should
the
decision
be
based
strictly
on
chemical
water
column
quality
(
i.
e.,
a
pollutant­
by­
pollutant
approach),
or
should
a
segment's
overall
quality
or
other
factors
be
considered
(
i.
e.,
a
water
body­
by­
water
body
approach)?
3.
Given
EPA's
current
thinking
that
both
approaches
may
be
acceptable
and
neither
is
necessarily
superior,
are
the
two
approaches
compatible
and
could
they
be
implemented
together?
4.
Should
application
of
tier
2
be
clarified
so
that
protection
of
assimilative
capacity
associated
with
non­
fishable/
swimmable
uses
is
clearly
required?
5.
What
methods
are
currently
being
used
by
States
and
Tribes
to
define
``
significant
degradation''?
6.
How
should
``
significant
degradation''
be
defined?
Is
there
a
need
for
a
nationally
consistent
approach?
Should
EPA
issue
additional
guidance,
or
revise
the
regulation
to
include,
for
purposes
of
implementing
tier
2
requirements,
a
definition
of
significant
degradation?
Are
categorical
exemptions
appropriate,
and
if
so,
under
what
circumstances?
7.
How
should
cumulative
effects
in
a
watershed
be
considered
in
assessing
the
significance
of
the
degradation
that
will
occur
as
a
result
of
a
proposed
activity?
8.
How
should
the
``
necessity''
of
degradation
be
determined?
When
should
the
costs
of
less
degrading
alternatives
be
considered
reasonable?
9.
How
should
significant
degradation
be
evaluated
for
pollutants
where
no
numeric
criterion
has
been
adopted?
10.
Is
additional
Agency
guidance
or
regulatory
requirements
necessary
to
help
States
and
Tribes
address
social
and
economic
importance
(
e.
g.,
additional
methods
or
options
beyond
those
discussed
in
the
March
1995
Interim
Economic
Guidance
document)?
11.
Should
evaluating
the
importance
of
proposed
discharges
be
entirely
a
State
or
Tribal
determination
and
not
be
a
required
element
for
EPA
review?
12.
Would
it
be
appropriate
to
revise
the
regulation
to
clarify
the
relationship
between
nonpoint
source
controls
and
tier
2
antidegradation
requirements?
13.
Should
EPA
revise
the
regulation
to
expressly
state
that
States
and
Tribes
are
to
consider
the
303(
d)
listing
status
of
a
water
body,
and
the
information
supporting
that
status,
when
determining
whether
a
proposed
activity
that
is
expected
to
degrade
water
quality
in
that
water
body
can
be
authorized
under
tier
2
of
the
State's
or
Tribe's
antidegradation
provisions?
14.
Is
greater
consistency
between
individual
State
and
Tribal
programs
desirable
and,
if
so,
what
changes
may
be
needed
to
the
regulation
or
EPA
guidance
to
ensure
that
the
tier
2
provision
is
implemented
in
a
nationally
consistent
manner?

5.
40
CFR
131.12
(
a)(
3)
``
Tier
3''

Tier
3
of
the
antidegradation
policy
is
intended
to
identify
and
protect
waters
of
extraordinary
ecological,
recreational
or
other
significance.
Tier
3
of
the
antidegradation
policy
incorporates
the
36786
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
concept
of
Outstanding
National
Resource
Waters
(
ONRW).
The
rationale
for
this
provision
is
that
some
water
bodies
are
of
such
high
quality
or
of
such
exceptional
ecological
significance
that
the
commonly
applied
designated
uses
such
as
warm
water
fishery
and
primary
contact
recreation
and
criteria
to
protect
those
uses
are
not
suitable
or
may
not
provide
adequate
protection
to
maintain
the
high
water
quality
or
ecological
significance
in
a
given
water
body.
ONRWs
are
intended
to
include
the
highest
quality
waters
of
the
United
States.
Additionally,
the
ONRW
antidegradation
classification
offers
special
protection
for
waters
of
``
exceptional
ecological
significance,''
i.
e.,
those
water
bodies
which
are
important,
unique,
or
sensitive
ecologically,
but
whose
water
quality,
as
measured
by
the
traditional
characteristics
such
as
dissolved
oxygen
or
pH,
may
not
be
particularly
high,
such
as
thermal
springs.
Waters
of
exceptional
ecological
significance
also
include
waters
whose
characteristics
cannot
adequately
be
described
by
traditional
parameters
(
such
as
wetlands
and
estuaries).
Tier
3
of
the
antidegradation
policy
provides
the
highest
level
of
protection
to
water
bodies
by
prohibiting
the
lowering
of
water
quality.
The
only
exception
to
this
prohibition
as
discussed
in
the
preamble
to
the
water
quality
standards
regulation
is
for
activities
that
result
in
short­
term
and
temporary
changes
in
the
water
quality
of
the
ONRW.
EPA
guidance
has
not
defined
temporary
and
short­
term
specifically,
but
views
these
terms
as
limiting
water
quality
degradation
for
weeks
or
months,
not
years.
The
intent
is
to
limit
degradation
to
the
shortest
possible
time.
a.
Designating
ONRWs.
The
designation
of
water
bodies
as
ONRWs
has
been
limited
in
its
application.
Overall,
there
are
relatively
few
water
bodies
designated
as
ONRWs
in
the
United
States,
although
some
States
have
designated
a
high
percentage
of
State
waters
as
ONRWs.
Several
States
have
been
reluctant
to
adopt
ONRWs
because
of
concerns
regarding
the
process
for
adopting
ONRW
classifications
and
the
level
of
protection
afforded
to
a
water
once
it
is
classified
as
an
ONRW.
Regarding
the
process
for
adoption
of
ONRWs,
the
existing
regulation
requires
the
State
or
Tribe
to
provide
an
ONRW
level
of
protection
in
their
antidegradation
policies,
but
there
is
no
requirement
that
any
water
body
be
so
designated
or
any
specificity
as
to
how
that
is
to
be
done.
One
way
to
address
this
issue
may
be
for
EPA
to
amend
the
regulation
to
require
States
and
Tribes
to
establish
a
nomination
process
with
criteria
guidelines
in
which
the
public
could
petition
the
State
or
Tribe
for
designation
of
certain
waters
as
ONRWs.
It
would
then
be
up
to
the
State
or
Tribe
to
set
criteria
for
the
ONRW
selection
process
with
the
final
decision
made
by
the
State
or
Tribe
after
consideration
of
the
public
comment.
EPA
currently
recommends
three
categories
of
waters
which
could
be
eligible
for
ONRW
designation:
waters
of
(
1)
National
and
State
parks,
(
2)
wildlife
refuges,
and
(
3)
exceptional
recreational
or
ecological
significance.
Regarding
the
level
of
protection
that
is
afforded
to
a
water
body
once
it
is
classified
as
an
ONRW,
a
common
concern
is
that
classifying
a
water
as
ONRW
will
result
in
a
federal
prohibition
on
any
further
development
of
any
kind
in
the
watershed.
As
described
above,
the
federal
antidegradation
policy
regarding
ONRWs
is
that
once
classified
as
an
ONRW,
the
water
quality
of
the
ONRW
must
be
maintained
and
protected.
One
way,
but
perhaps
not
the
only
way,
to
ensure
that
the
water
quality
is
maintained
and
protected
would
be
to
prohibit
activities
that
would
generate
additional
pollutant
loads
and
or
water
quality
impacts
in
the
ONRW.
This
approach
is
commonly
referred
to
as
``
no
new
or
increased
discharge''
and
was
explained
by
EPA
in
its
promulgation
of
antidegradation
provisions
for
the
State
of
Pennsylvania
in
1996
(
61
FR
64816,
December
9,
1996).
As
discussed
in
the
Pennsylvania
rule,
the
federal
policy
requiring
the
water
quality
to
be
maintained
and
protected
is
subject
to
some
interpretation
by
States
and
Tribes.
EPA
believes
there
is
considerable
uncertainty
from
jurisdiction
to
jurisdiction
concerning
the
impact
of
the
ONRW
classification
on
the
local
community
or
the
State
or
Tribe.
How
will
the
State
or
Tribe
handle
future
needs
for
development
in
the
area
of
the
ONRW?
What
role
does
EPA
play
in
ensuring
that
the
State
or
Tribe
provides
the
highest
protection
measures
to
ONRWs?
EPA's
current
thinking
is
that
this
``
no
further
development
in
the
watershed
prohibition''
may
be
an
overly
strict
interpretation
of
the
protection
required
by
tier
3
and
that
a
public
debate
is
necessary
to
clarify
the
level
or
range
of
protection
that
is
afforded
to
a
water
by
classifying
it
as
an
ONRW,
and
how
that
level
or
range
should
be
determined.
One
way
to
remove
uncertainty
surrounding
the
implications
of
ONRW
designations
is
for
States
and
Tribes
to
adopt
concurrent
with
the
ONRW
the
implementation
methods
for
that
water
body
that
define
what
attributes
of
the
water
will
be
protected
and
how
this
will
be
accomplished
by
both
point
and
nonpoint
sources.
It
may
make
sense
for
the
regulation
to
include
this
requirement
in
order
for
all
parties
concerned
to
know
the
impact
on
development
of
such
a
designation
before
adopting
an
ONRW.
i.
Relationship
of
Tier
3
to
the
Wild
and
Scenic
Rivers
Act.
Additionally
some
States
have
not
adopted
waters
as
ONRWs
when
there
has
been
concern
regarding
ONRW
requirements
and
the
requirements
of
a
wild,
scenic,
or
recreational
water
body.
Although
the
Department
of
Interior
(
DoI)
founded
the
antidegradation
policy
from
which
the
concept
of
an
outstanding
national
resource
water
(
ONRW)
that
EPA
currently
uses
evolved,
an
ONRW
is
different
from
the
Wild
and
Scenic
Rivers
program
administered
by
DoI.
ONRWs
are
designated
by
the
State
or
Tribe
in
their
water
quality
standards.
Wild
and
scenic
rivers
are
given
their
designation
by
Congress
or
the
Department
of
Interior
pursuant
to
the
Federal
Wild
and
Scenic
Rivers
Act.
The
main
purpose
of
the
Wild
and
Scenic
Rivers
Act
is
to
keep
waters
freeflowing
The
main
purpose
of
an
ONRW
designation
is
to
maintain
and
protect
high
quality
waters
that
constitute
outstanding
resources
due,
for
example,
to
their
exceptional
recreational
or
ecological
significance,
which
can
include
free­
flowing
water.
EPA
does
not
see
any
conflict
between
these
two
programs.
b.
Tier
3
Implementation.
EPA
in
chapter
4
of
the
Water
Quality
Standards
Handbook
interprets
the
``
water
quality
to
be
maintained
and
protected''
provision
of
the
regulation
as
requiring
no
new
or
increased
discharges
to
ONRWs
and
no
new
or
increased
discharge
to
tributaries
to
ONRWs
that
would
result
in
lower
water
quality
in
the
ONRWs.
The
only
exception
is
for
short­
term
and
temporary
changes.
In
contrast,
some
States,
Tribes,
and
EPA
Regions
have
interpreted
this
provision
to
allow
new
discharges
as
long
as
the
water
quality
is
either
maintained
or
improved.
Alternatively,
some
States,
Tribes
and
Regions
have
interpreted
water
quality
in
terms
of
the
characteristics
for
which
the
water
body
was
selected
to
be
an
ONRW
and
have
strictly
maintained
those
characteristics
while
allowing
other
characteristics
to
become
degraded.
EPA
has
also
allowed
a
proposed
activity
that
will
result
in
a
new
or
expanded
source
where
the
applicant
agrees
to
implement
or
36787
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
finance
upstream
controls
of
point
or
nonpoint
sources
sufficient
to
offset
the
water
quality
effects
of
the
proposed
activity.
This
offset
is
generally
called
trading
and
is
accomplished
through
a
TMDL
pursuant
to
CWA
Section
303(
d)
requirements.
Such
TMDLs
include
an
appropriate
margin
of
safety
and
address,
in
particular,
the
uncertainties
associated
with
any
proposed
nonpoint
source
controls,
as
well
as
variability
in
effluent
quality
for
point
sources.
This
variability
in
interpretation
has
created
ONRWs
across
the
Nation
that
vary
in
terms
of
the
stringency
of
point
source
controls,
and
types
of
water
bodies
considered
to
be
ONRWs.
Restrictions
on
physical
changes
have
also
been
implemented
in
an
inconsistent
manner.
EPA
is
considering
whether
the
existing
ONRW
protection
program
is
addressing
an
appropriate
universe
of
waters
and
whether
the
flexibility
provided
under
the
regulation,
in
terms
of
coverage
and
protection
requirements,
needs
to
be
further
restricted,
maintained,
or
expanded.
It
may
make
sense
to
have
an
ONRW
designation
which
is
permanent
and
allows
no
change
in
water
quality
and
applicable
to
few
waters
while
creating
a
subset
of
waters
which
can
have
some
change
in
water
quality
under
certain
circumstances.
c.
Tier
21 
2.
Several
States
and
Tribes
have
already
created,
as
part
of
their
antidegradation
policy,
a
provision
that
is
in
between
EPA's
recommended
tier
2
 
high
quality
waters
and
tier
3
 
Outstanding
National
Resource
Waters,
sometimes
referred
to
as
Tier
21 
2.
This
additional
tier
is
given
various
names,
such
as
Outstanding
State
Resource
Waters,
Outstanding
Tribal
Waters,
Special
Protection
Waters,
or
Water
of
Exceptional
Significance.
When
it
supplements
tier
2
and
tier
3
provisions,
EPA
has
accepted
this
provision
as
being
consistent
with
the
intent
and
spirit
of
the
antidegradation
policy.
Inclusion
of
a
tier
21 
2
within
the
regulation
would
encourage
States
and
Tribes
to
apply
more
stringent
controls
than
would
be
required
under
tier
2
but
with
more
flexibility
to
make
adjustments
in
criteria
and
permitting
decisions
than
would
normally
be
allowed
if
the
water
body
in
question
were
designated
as
an
ONRW.
Any
additional
flexibility
that
might
be
created
by
a
tier
21 
2
classification
to
allow
additional
activities
that
could
marginally
affect
water
quality,
might
not
be
necessary
where
a
State
or
Tribe
(
or
EPA)
considers
such
flexibility
to
already
exist
in
the
context
of
the
ONRW
classification.
In
commenting
on
the
flexibility
afforded
by
the
tier
21 
2
classification,
commenters
are
urged
to
state
their
understanding
of
the
flexibility
currently
afforded
in
the
ONRW
classification.

Request
for
Comments
on
Antidegradation
Tier
3
EPA
seeks
comment
on
the
following
questions:
1.
Should
EPA
add
definitions
of
important
terms
to
the
ONRW
part
of
the
regulation,
including
a
definition
of
``
degradation''
which
clarifies
that
temporary
or
short­
term
effects
on
ONRW
waters
could
be
authorized?
Should
definitions
of
``
short­
term''
and
``
significant''
also
be
included?
2.
Should
EPA
require
States
and
authorized
Tribes
to
establish
both
a
process
and
qualification
criteria
which
would
allow
the
public
to
nominate
waters
for
the
ONRW
designation?
Would
EPA
guidance
be
helpful?
3.
Should
the
tier
21 
2
antidegradation
policy
concept
be
explicitly
recognized
in
the
federal
regulation
and
what,
if
any,
limits
or
factors
for
application
of
the
tier
should
be
included?
4.
States
(
and
Tribes)
have
differing
interpretations
of
the
level
of
protection
afforded
ONRWs.
Should
EPA
further
specify
in
the
regulation
what
maintaining
and
protecting
water
quality
in
ONRWs
means?

6.
40
CFR
131.12
(
a)(
4)
``
Thermal
Discharges''

The
requirement
to
prevent
potential
water
quality
impairment
associated
with
thermal
discharges
contained
in
§
131.12
(
a)(
4)
of
the
regulation
is
intended
to
coordinate
the
requirements
and
procedures
of
the
antidegradation
policy
with
those
established
in
the
CWA
for
setting
thermal
discharge
limitations.
Regulations
implementing
section
316
may
be
found
at
40
CFR
124.66.
The
statutory
scheme
and
legislative
history
indicate
that
limitations
developed
under
section
316
take
precedence
over
other
requirements
of
the
CWA.
EPA
is
not
requesting
comment
on
this
section
of
the
regulation.
This
provision
is
mentioned
here
only
in
the
interest
of
completeness.

E.
Mixing
Zones
1.
Background
The
current
regulation
(
at
40
CFR
131.13)
describes
States'
and
Tribes'
discretionary
authority
to
include,
in
their
water
quality
standards,
policies
that
affect
the
implementation
of
those
standards.
For
example,
States
and
Tribes
may
adopt
policies
on
mixing
zones,
variances,
and
schedules
of
compliance
for
water
quality­
based
NPDES
permit
limits.
If
included
in
their
water
quality
standards
or
other
implementing
regulations,
States
and
Tribes
are
required
to
submit
such
policies
to
EPA
for
review
and
approval.
The
policies
governing
the
implementation
of
water
quality
standards
are
inseparable
from
the
standards
themselves
and,
consequently,
EPA
reviews
both
to
determine
whether
implementation
policies
are
compatible
with
the
State
or
Tribal
water
quality
standards
provisions,
technically
well
founded
and
consistent
with
the
CWA.
Concerns
have
been
expressed
both
by
the
regulated
community
and
environmental
groups
over
the
lack
of
specificity
in
State
and
Tribal
mixing
zone
policies
and
implementation
procedures
adopted
under
this
general
policies
provision.
These
groups
believe
that
this
lack
of
specificity
may
result
in
rather
subjective
and
inconsistent
implementation
of
water
quality
standards,
from
site­
to­
site.
EPA
has
also,
through
its
ten
regional
offices,
not
always
applied
uniform
standards
in
reviewing
individual
States'
and
Tribes'
mixing
zone
provisions.
In
encouraging
the
implementation
of
water
quality
management
activities
consistent
with
a
broader
watershed
approach,
EPA
has
encountered
inconsistent
implementation
of
mixing
zone
provisions
across
State
and
Tribal
borders,
within
whole
watersheds,
and
sometimes
along
a
single
water
body.
Remedies
to
water
quality
problems
designed
along
watershed
boundaries
can
be
limited
in
their
effectiveness
as
a
result
of
differing
policies,
procedures
and
treatment
of
the
same
water
body
by
different
authorities.
A
certain
amount
of
flexibility
is,
however,
essential
when
dealing
with
complex
water
quality
problems
on
a
watershed
or
basin
scale.
EPA's
current
thinking
is
that
it
is
preferable
to
be
more
explicit
about
where
the
program
requires
consistency
and
where
flexibility
is
allowed
or
encouraged.
The
current
regulation
does
not
articulate
any
EPA
requirements
regarding
the
content
of
mixing
zone
implementation
procedures.
Rather,
EPA
guidance
addressing
mixing
zones,
and
stream
design
flows
is
contained
in
several
documents,
including
the
Water
Quality
Standards
Handbook:
Second
Edition
(
the
Handbook)
and
the
Technical
Support
Document
for
Water
Quality­
based
Toxics
Control,
March,
1991
(
the
TSD).
Although
program
and
technical
guidance
identifies
the
approaches
to
standards
implementation
which
EPA
recommends
and
considers
protective
of
water
quality,
guidance
is
not
equally
effective
at
delineating
what
constitutes
36788
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
minimally
acceptable
content
or
the
approaches
EPA
considers
to
be
not
approvable
or
inconsistent
with
the
CWA.
Further,
most
regulatory
agencies,
as
well
as
the
regulated
community,
are
most
concerned
with
what
is
required
rather
than
what
is
recommended.
Policy
or
guidance
is
not
binding
whereas
regulation
is.
Guidance
is
better
designed
to
provide
detailed
descriptions
of
the
variety
of
technically
sound
implementation
approaches
and
their
underlying
scientific
basis;
regulation
provides
the
clearest
direction
regarding
required
minimal
program
content
and
identification
of
those
components
of
the
program
where
flexibility
is
allowed.
EPA
is
considering
an
expansion
of
the
section
of
the
regulation
addressing
general
policies
to
provide
clear,
detailed
and
specific
direction
to
States
and
Tribes
on
the
development
and
content
of
mixing
zone
policies
and
implementation
procedures.
EPA's
current
thinking
is
that
greater
specificity
within
this
portion
of
the
regulation
may
be
needed
to
clarify
the
minimum
necessary
elements
of
State
and
Tribal
mixing
zone
policy
and
implementation
procedures.
EPA's
current
thinking
is
that
this
area
of
the
regulation
needs
to
articulate
a
clear
level
of
national
consistency
in
mixing
zone
implementation
that
results
in
a
consistent
level
of
protection
across
the
country
and
at
the
same
time,
where
State
and
Tribal
flexibility
is
not
only
encouraged,
but
possibly
essential
to
program
efficiency
and
accuracy.

2.
EPA
Policy
and
Guidance
on
Mixing
Zones
The
concept
of
mixing
zones
as
a
regulatory
tool
to
address
the
incomplete
mixing
of
wastewater
discharges
in
receiving
waters
has
been
embraced
by
both
EPA
and
its
predecessor
agencies
as
part
of
a
larger
regulatory
effort
to
ensure
that
point
source
discharges
of
wastes
do
not
impair
beneficial
uses.
EPA
interprets
the
CWA
as
allowing
the
use
of
mixing
zones
as
long
as
the
provisions
addressing
toxicity
at
section
101(
a)(
3)
are
met
and
the
designated
uses
of
the
water
body
as
a
whole
are
protected.
One
court
has
considered
the
application
of
a
mixing
zone
in
a
discharge
permit
and
upheld
EPA's
use
of
a
limited
mixing
zone
(
See
Hercules
v.
EPA,
598
F.
2d
91
(
D.
C.
Cir.
1978)).
The
concept
of
a
mixing
zone
is
covered
by
a
series
of
guidance
documents
issued
by
EPA
and
its
predecessor
agencies
(
see,
for
example:
Water
Quality
Criteria
(
Green
Book),
Federal
Water
Pollution
Control
Administration,
1968,
pp.
29
 
31;
Water
Quality
Criteria
1972
(
Blue
Book),
EPA,
March
1973,
pp.
112
 
115,
231
 
232,
403
 
457;
Guidelines
for
Developing
or
Revising
Water
Quality
Standards,
January
1973;
Chapter
5
 
Guidelines
for
State
and
Areawide
Water
Quality
Management
Program
Development,
November,
1976;
Allocated
Impact
Zones
for
Areas
of
Non­
Compliance,
EPA
Region
1,
October
1986;
The
Water
Quality
Standards
Handbook,
August,
1994,
pp.
5
 
1
to
5
 
11;
Technical
Support
Document
for
Water
Quality­
based
Toxics
Control
(
TSD),
March,
1991,
pp.
31
 
34,
56
 
60,
69
 
89).
Many
definitions
of
mixing
zones
have
been
offered,
differing
primarily
by
perspective
(
i.
e.,
engineering,
hydrological,
ecological,
regulatory)
and
their
application.
From
a
hydrological/
engineering
perspective,
mixing
zones
can
be
defined
based
upon
the
recognition
of
incomplete
mixing
of
an
effluent
with
its
receiving
water
(
e.
g.,
``
that
area
or
volume
of
dilution
water
necessary
to
reduce
contaminant
concentrations
to
some
acceptable
level
or
to
a
totally
mixed
condition'').
Biologically,
mixing
zones
can
be
defined
based
on
the
premise
that
surface
water
quality
criteria
can
be
exceeded
under
limited
circumstances
without
causing
unacceptable
toxicity
or,
more
broadly,
impairment
of
the
designated
beneficial
uses
(
e.
g.,
``
the
area
contiguous
to
a
discharge
where
receiving
water
quality
is
not
required
to
meet
water
quality
criteria
nor
other
requirements
applicable
to
the
receiving
water'').
EPA's
policy
on
the
use
of
mixing
zones
has
evolved
since
its
early
recognition
within
general
water
quality
guidance,
primarily
in
association
with
the
institution
and
evolution
of
the
NPDES
permit
program
(
e.
g.,
the
TSD).
Initially,
guidance
emphasized
the
need
to
ensure
that
the
biological
integrity
of
the
aquatic
community
in
the
receiving
stream
was
protected
and
that
such
determinations
must
be
based
on
sitespecific
evaluations.
In
the
late
1980'
s
EPA
and
authorized
NPDES
States
began
increasing
the
development
and
issuance
of
water
quality­
based
effluent
limits.
With
this
increase,
came
a
demand
for
widely
applicable
national
guidance
to
support
those
programs.
EPA
and
States,
in
essence,
needed
wasteload
allocation
and
water
qualitybased
permit
limit
derivation
methods
that
were
relatively
simple
to
use
and
could
be
implemented
with
little
sitespecific
data.
EPA
met
this
demand
by
issuing
revised
guidance
(
the
TSD
and
Handbook,
cited
above,
are
examples)
and
by
accepting
a
wide
range
of
State
mixing
zone
practices.
As
a
result,
mixing
zone
provisions
have
become
less
prescriptive
than
earlier
guidance
that
envisioned
data
rich,
site­
specific
studies,
and
more
reliant
on
often
cursory
evaluations,
general
mixing
assumptions,
and
best
professional
judgement.
EPA's
current
policy
addresses
mixing
zones
as
allocated
impact
zones
(
AIZs)
where
certain
numeric
water
quality
criteria
may
be
exceeded
as
long
as:
there
is
no
lethality
to
organisms
passing
through
the
mixing
zone,
there
are
no
significant
risks
to
human
health,
and
the
designated
and
existing
uses
of
the
water
body
are
not
impaired
as
a
result.
These
AIZs
or
mixing
zones,
if
disproportionately
large,
could
unacceptably
impact
the
integrity
of
the
aquatic
ecosystem
and
have
unanticipated
ecological
consequences
on
the
water
body
as
a
whole
resulting
in
impairment
of
the
designated
or
existing
uses.
Therefore,
EPA's
policy
has
emphasized
a
holistic
approach
to
mixing
zone
regulation
which
considers
location,
size,
shape,
outfall
design
and
in­
zone
quality.
Mixing
zone
guidance
produced
by
EPA
since
1972
has
consistently
emphasized
the
need
to
protect
both
nonmotile
benthic
and
sessile
organisms
in
the
mixing
zone
as
well
as
swimming
and
drifting
organisms
(
Water
Quality
Criteria
1972).
States
and
Tribes,
however,
have
focused
primarily,
if
not
exclusively,
on
the
protection
of
swimming
and
drifting
organisms
and
the
need
to
provide
``
zones
of
passage''
within
waters
with
mixing
zones.
In
its
dependence
upon
conditions
protective
of
swimming
and
drifting
organisms
to
define
mixing
zones,
this
approach
results
in
an
incomplete
implementation
of
the
original
concept
supporting
mixing
zones.
As
originally
designed,
EPA's
mixing
zone
policy
provided
for
the
prevention
of
lethality
to
swimming
and
drifting
organisms
by
limiting
the
size
of
the
mixing
zone
and
to
nonmotile
organisms
by
limiting
the
placement
or
location
of
mixing
zones.
Although
existing
EPA
guidance
on
the
implementation
of
mixing
zones
(
cited
above)
is
quite
detailed,
at
present,
the
regulation
itself
simply
provides
that
States
and
Tribes
may
adopt,
as
part
of
their
water
quality
standards,
mixing
zone
policies
and
that
such
policies
are
subject
to
EPA
review
and
approval
(
40
CFR
131.13).
In
addition,
EPA
may
separately
review
individual
State
and,
once
approved
to
administer
NPDES,
Tribal
mixing
zone
determinations
as
part
of
the
wasteload
allocation
and
NPDES
permit
review
process,
outside
the
standards
adoption
and
review
process
to
ensure
appropriate
implementation
of
the
State's
mixing
zone
policy.
36789
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
EPA
is
considering
expanding
the
current
provisions
at
40
CFR
131.13
addressing
State
and
Tribal
development
of
mixing
zone
policies
within
their
water
quality
standards
program
to
address
the
content
and
design
of
those
policies.

3.
State
and
Tribal
Mixing
Zone
Policies
While
there
are
advantages
to
the
more
flexible
general
approach
adopted
in
the
late
1980'
s,
the
generality
of
the
current
regulation
has
led
to
some
uncertainty
as
to
what
constitutes
an
approvable
mixing
zone
policy.
Because
the
regulation
lacks
detailed
requirements
concerning
EPA's
standards
of
review
of
State
and
Tribal
mixing
zone
provisions,
EPA
is
considering
changing
the
language
regarding
State
and
Tribal
adoption
of
mixing
zone
policies
to
address
specifically
the
content
of
such
policies.
EPA's
current
thinking
is
that
greater
specificity
would
provide
for
increased
public
participation
in
State,
Tribal
and
Federal
decision­
making;
a
clearer
understanding
by
the
State,
Tribe
and
public
of
what
EPA
considers
an
approvable
mixing
zone
policy;
a
reduction
in
the
number
of
NPDES
permit
appeals
and
objections
based
on
differing
interpretations
of
a
State
or
Tribal
mixing
zone
policy;
and
a
more
consistent
review
of
State
and
Tribal
submissions
by
EPA
itself.
Fundamental
to
any
such
policy,
EPA
is
considering
requiring
States
and
Tribes
to
indicate
explicitly
in
their
water
quality
standards
whether
or
not
they
allow
mixing
zones
for
each
of
the
various
uses
designated
for
a
given
water
body.
Such
provisions
could
address
mixing
zones
applied
to
either
acute
or
chronic
aquatic
life
and
other
water
quality
criteria
(
e.
g.,
public
water
supply,
livestock
watering,
wildlife
protection,
etc.).
Under
this
approach,
if
the
State
or
Tribe
does
not
explicitly
authorize
mixing
zones,
then
no
mixing
zones
would
be
allowed
in
State
or
Tribal
waters,
and
all
applicable
criteria
would
have
to
be
met
at
the
end­
of­
pipe.
(
Memorandum
from
Robert
Perciasepe,
Assistant
Administrator
for
Water
to
Water
Program
Directors,
Regions
I­
X,
Subject:
EPA
Guidance
on
Application
of
State
Mixing
Zone
Policies
in
EPAIssued
NPDES
Permits,
August
6,
1996).
Alternatively,
States
and
Tribes
could
determine
that
such
prohibitions
would
be
applied
to
only
a
subset
of
uses
or
pollutants
rather
than
across
all
use
categories
and
pollutants.
Some
States
or
Tribes
have
used
this
approach
to
prohibit
mixing
zones
in
their
highest
use
classes
(
e.
g.,
class
AA),
while
allowing
mixing
zones
in
more
highly
impacted
watersheds
(
e.
g.,
class
C
or
D
waters).
States
and
Tribes
could
also
be
required
to
specify
the
conditions
under
which
mixing
zones
are
allowed
in
each
site­
specific
application
and
the
limitations
to
those
applications
(
e.
g.,
size,
shape,
length,
placement,
etc.).
In
addition,
States
and
Tribes
could
be
required
to
identify
any
circumstances,
pollutants,
locations
or
conditions
for
which
the
use
of
mixing
zones
is
prohibited.
States
and
Tribes
could
specify
circumstances
where
only
chronic
mixing
zones
would
be
allowed
(
i.
e.,
no
acute
mixing
zone
or
zone­
ofinitial
dilution)
and
circumstances
where
acute
and/
or
chronic
mixing
zones
would
be
prohibited.
Current
EPA
guidance,
for
example,
recommends
States
and
Tribes
consider
prohibition
of
mixing
zones
when
bioaccumulative
pollutants
are
present
in
the
discharge
or
where
an
effluent
is
known
to
attract
biota.
Other
circumstances
where
mixing
zone
prohibitions
or
location
restrictions
might
be
appropriate
include
areas
used
by
aquatic
life
for
breeding
or
feeding,
locations
of
shellfish
beds,
locations
of
critical
habitat
for
threatened
and
endangered
species,
across
tributary
mouths,
shallows,
near
shore
areas
and
in
areas
of
critical
habitat.
This
change
would
clarify
in
the
regulation
the
State
and
Tribal
general
authority
to
provide
mixing
zones,
the
scope
of
that
authority,
and
the
sitespecific
factors
evaluated
by
States
and
Tribes
when
deciding
whether
a
mixing
zone
is
authorized
in
each
individual
case.
EPA
is
considering
making
this
potential
clarification
to
the
regulation,
its
implications,
and
how
mixing
zone
policies
can
be
designed
to
better
support
and
foster
a
watershed
management
framework.

4.
Mixing
Zone
Requirements
Some
States
and
Tribes
that
have
adopted
mixing
zone
provisions
within
their
water
quality
standards
have
not
specified
mixing
zone
requirements
(
e.
g.,
water
quality
within
mixing
zones,
the
allowable
size
of
mixing
zones,
etc.)
under
their
mixing
zone
policies.
EPA
is
therefore
considering
including
as
regulatory
requirements
certain
specifications
derived
from
EPA's
guidance
on
mixing
zones.
Regarding
policy
content,
EPA
might
revise
the
regulation
to
require
that
State
and
Tribal
mixing
zone
policies
address
a
minimum
number
of
elements.
Those
required
elements
might
include
provisions
that:
identify
conditions
and
circumstances
(
e.
g.,
particular
locations)
when
mixing
zones
are
not
permitted;
identify
any
pollutants
or
classes
of
pollutants
for
which
mixing
zones
are
prohibited;
identify
the
mechanisms
to
be
used
to
ensure
that
mixing
zones
do
not
impinge
on
ecologically
or
recreationally
sensitive
areas;
identify
the
mechanisms
to
be
used
to
determine
complete
and
incomplete
mixing
of
effluent
and
receiving
water;
identify
conditions
when
a
mixing
analysis
is
required;
identify
default
design
flows
for
implementing
criteria;
identify
maximum
allowable
mixing
zone
size
and
configuration,
as
well
as
how
mixing
zones
dimensions
are
determined;
specify
what
water
quality
conditions
must
be
met
within
mixing
zones;
state
whether
zones
of
initial
dilution
are
allowed;
and
state
whether
there
are
special
conditions
established
for
bioaccumulative
pollutants.
Identification
in
the
regulation
of
minimum
elements
of
State
or
Tribal
mixing
zones
procedures
would
establish
the
basis
for
EPA
review
and
approval
of
State
and
Tribal
mixing
zone
provisions.
It
would
also
facilitate
the
review
of
individual
mixing
zone
determinations
made
under
the
wasteload
allocation/
permit
approval
process
by
EPA,
other
agencies
and
the
public.
This
would
not
significantly
change
EPA's
guidance
or
current
approach
to
mixing
zone
policies.
Rather,
it
would
clarify
and
codify
the
basis
by
which
EPA
will
review
and
approve
or
disapprove
State
and
Tribal
mixing
zone
policies
and
their
sitespecific
implementation
through
NPDES
permits.
As
discussed
previously,
EPA's
mixing
zone
guidance
is
premised
fundamentally
on
the
prevention
of
lethality
within
the
mixing
zone
and
siting
such
that
areas
of
critical
habitat
are
avoided,
resulting
in
the
protection
of
designated
uses.
One
aspect
of
this
guidance
is
that,
for
aquatic
life
uses,
water
quality
within
the
mixing
zone
should
be
such
that,
at
a
specified
concentration
of
a
contaminant
(
i.
e.,
magnitude),
any
``
swimming
or
drifting''
organism
would
not
remain
in
the
mixing
zone
long
enough
to
receive
an
exposure
that
is
sufficiently
long
(
i.
e.,
duration)
to
cause
lethality.
If
the
combination
of
the
concentration
of
a
given
pollutant
or
the
combined
effect
of
multiple
pollutants
(
e.
g.,
whole
effluent
toxicity)
in
a
discharge
and
the
duration
of
exposure
to
that
concentration
are
low
enough,
there
is
no
lethality
within
the
mixing
zone,
and
the
criteria
(
magnitude
and
duration
components
together)
are
met.
This
approach,
however,
only
provides
protection
in
situations
in
which
water
column
organisms
pass
in
and
out
of
the
mixing
zone.
This
interpretation
does
not
adequately
36790
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
protect
stationary
or
sessile
organisms
within
the
mixing
zone;
organisms
that
remain
within
the
mixing
zone
for
extended
periods
because
the
mixing
zone
extends
into
feeding
or
breeding
areas
or
critical
habitat
(
e.
g.,
tributary
mouths,
shallows,
shoreline
habitat
in
large,
fast­
flowing
rivers);
critical
habitat
areas
for
endangered
or
threatened
species;
or
instances
where
mixing
zone
conditions
attract
organisms.
EPA's
mixing
zone
policy
and
guidance
address
those
instances
where
the
provisions
protecting
swimming
and
drifting
organisms
are
not
adequate
to
protect
nonmotile
benthic
and
sessile
organisms
or
critical
habitat
areas
by
limiting
the
location,
size
and
shape
of
mixing
zones.
In
some
instances,
this
policy
has
been
implemented
in
a
fragmented
manner.
In
such
instances,
these
latter
restrictions
to
mixing
zone
placement
are
inadequately
addressed.
EPA
always
has
discretion
to
object
to,
and
take
over
if
necessary,
permits
that
provide
site­
specific
mixing
zones
in
cases
where
such
mixing
zones
would
fail
to
protect
all
aspects
of
designated
uses.
However,
oversight
of
individual
permits
is
not
an
efficient
approach
to
resolving
program­
level
issues.
To
clarify
the
meaning
of
its
policy
and
ensure
a
more
complete
implementation
of
protective
mixing
zone
provisions,
EPA
is
considering
changes
to
the
regulation.
EPA
could
require
that
State
and
Tribal
mixing
zone
policies
specifically
identify
prohibitions
(
where
appropriate)
or
limit
mixing
zones
where
necessary
to
protect
existing
or
designated
uses.
Some
States
and
Tribes
already
include
prohibitions
against
the
use
of
mixing
zones
where
they
could
intrude
upon
public
drinking
water
supply
intakes
or
public
swimming
beaches,
or
where
mixing
zones
prove
to
be
attractive
to
aquatic
life
or
wildlife
(
e.
g.,
water
temperature).
EPA
might
require
that
State
and
Tribal
mixing
zone
provisions
specifically
address
instances
such
as
these
where
restrictions
on
mixing
zones
are
appropriate.
Additionally,
EPA
is
considering
requiring
that
State
and
Tribal
water
quality
standards
include
a
description
of
the
State's
or
Tribe's
methodology
for
specifying
the
location,
geographic
boundaries,
size,
shape
and
in­
zone
quality
of
mixing
zones.
EPA
could
also
clarify
its
current
policy
that
an
approvable
mixing
zone
methodology
must
be
scientifically
defensible
and
ensure
the
protection
of
designated
uses
in
the
water
body
as
a
whole.
This
would
require
that
the
methodology,
at
a
minimum,
be
sufficiently
precise
to
support
consistent
regulatory
actions
(
e.
g.,
an
NPDES
permit).
EPA
is
considering
this
change
to
ensure
that
State
and
Tribal
mixing
zones
do
not
adversely
affect
the
integrity
of
State
and
Tribal
waters
and
to
address
inconsistent
allocation
of
mixing
zones
from
site­
to­
site.
Under
this
approach,
for
example,
when
a
State
or
Tribe
assumes
that
either
complete
or
incomplete
mixing
occurs,
the
State's
or
Tribe's
implementation
procedure
could
require
the
analyses
supporting
the
mix
assumption
to
be
documented
in
the
record
(
e.
g.,
permit
fact
sheet).
EPA
is
considering
the
need
for
additional
language
in
the
water
quality
standards
regulation
to
clarify
the
essential
elements
of
State
or
Tribal
mixing
zone
provisions
and,
alternatively,
whether
such
language
would
be
better
established
in
guidance.
EPA's
current
thinking
is
that
a
certain
amount
of
professional
judgement
is
necessary
in
making
site­
specific
mixing
zone
determinations
and
that
clarifications
to
the
regulation
regarding
the
minimum
mixing
zone
policies
and
implementation
procedures
should
not
preclude
such
flexibility.
However,
the
policy
and
implementation
procedures
should
be
clarified
so
that
the
guidelines
and
framework
for
making
site­
specific
mixing
zone
determinations
are
clear
to
everyone.

5.
Mixing
Analyses
The
above
discussion
focuses
on
establishing
State
and
Tribal
mixing
zone
policies
and
procedures.
The
following
discussion
addresses
the
application
of
such
procedures
in
individual
permitting
decisions.
Where
point
source
discharges
mix
in
a
slow
or
``
incomplete''
manner
with
receiving
waters
and
the
State
or
Tribe
has
authority
to
provide
a
mixing
zone,
EPA
guidance
recommends
that
a
mixing
zone
analysis
be
incorporated
into
the
derivation
of
water
qualitybased
effluent
limits
(
WQBELs)
in
NPDES
permits.
The
mixing
zone
analysis
should
demonstrate
compliance
with
State
or
Tribal
mixing
zone
requirements
(
e.
g.,
size,
shape,
location
and
in­
zone
quality)
that
are
included
in
the
water
quality
standards.
Providing
a
mixing
zone
in
incompletemix
situations
acknowledges
the
mixing
behavior
of
the
discharge
and
limits
excursions
above
criteria
to
a
specified
zone.
Where
a
discharge
mixes
with
the
receiving
water
in
a
rapid
and
``
complete''
manner,
by
definition
a
mixing
zone
analysis
is
not
needed
and
an
evaluation
of
the
assimilative
capacity
of
the
receiving
water
and
a
dilution
allowance
based
on
stream
design
flow
conditions
specified
in
the
State
or
Tribal
water
quality
standards
is
often
incorporated
into
the
derivation
of
WQBELs.
Presently,
all
State­
issued
NPDES
permits
are
reviewable
by
EPA.
EPA
may
object
to
individual
permits
and
assume
authority
to
issue
such
permits.
When
EPA
is
the
permit
issuing
authority,
it
must
follow
the
applicable
State
or
Tribal
water
quality
standards
and
ensure
that
any
water
quality­
based
effluent
limits
in
the
permit
are
derived
from
and
comply
with
the
applicable
State
or
Tribal
water
quality
requirements.
A
permit
that
does
not
include
a
defensible
mixing
zone
analysis
might
not
fully
protect
downstream
designated
uses.
A
common
example
is
where
a
discharge
mixes
slowly
(
i.
e.,
incomplete
mixing
is
occurring),
but
the
permit
limit
is
based
on
an
assumption
that
the
entire
design
flow
of
the
stream
rapidly
and
completely
dilutes
the
effluent.
When
this
does
not
occur
and
not
all
of
the
dilution
water
mixes
rapidly
with
the
effluent
discharge,
the
result
may
be
a
lengthy
downstream
plume
(
i.
e.,
mixture
of
effluent
and
surface
water)
with
water
quality
characteristics
that
exceed
applicable
chemical­
specific
or
toxicity
criteria,
are
potentially
lethal
to
aquatic
life,
and
may
impair
the
designated
use.
Such
plumes
are
of
concern
because:
(
1)
Chemical­
specific
criteria,
ambient
toxicity
criteria
or
other
narrative
criteria
may
not
be
achieved
in
the
extended
plume;
(
2)
Effluent
plumes
can
extend
far
downstream,
causing
impact
beyond
the
limited
area
of
a
mixing
zone
and
resulting
in
use
impairment;
(
3)
There
may
be
intakes
for
public
drinking
water
systems
located
downstream,
but
within
reach
of
an
extended
plume;
(
4)
Effluent
plumes
may
be
located
along
the
shore
in
shallow
waters
that
are
critical
nursery
areas
for
sensitive
species
and
which
constitute
important
or
critical
habitat,
particularly
in
large,
channelized
rivers;
(
5)
Aquatic
life
might
be
attracted
to
the
plume
because
of
its
temperature
differential
or
other
characteristics;
(
6)
Threatened
or
endangered
species
may
reside
within
or
near
the
plume
area,
and
(
7)
Additional
dischargers
may
be
located
downstream
and
the
cumulative
effects
of
all
discharges
may
not
be
adequately
considered,
particularly
regarding
unintended
overlapping
plumes.
EPA
believes
the
rate
of
ambient
mixing
and
the
complete
versus
incomplete
mix
decision
is
a
critical
but
frequently
overlooked
component
of
water
quality­
based
permitting.
36791
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Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
Although
a
mixing
zone
analyses
requires
site­
specific
information
and
additional
resources,
EPA
believes
that
the
approach
currently
followed
by
some
States
and
Tribes
might
be
too
simplistic,
might
allow
lethality
within
areas
of
critical
habitat
or
ecological
importance
and
may
not
fully
protect
designated
uses.
EPA's
current
thinking
is
that
the
regulation
should
be
made
more
explicit
as
to
the
circumstances
under
which
mixing
zones
must
be
supported
by
site­
specific
data
and
analysis.
EPA
is
considering
the
need
for
specific
requirements
within
the
regulation
governing
the
development
and
content
of
mixing
zone
analysis
procedures
as
part
of
State
and
Tribal
implementation
procedures.

6.
Narrative
Criteria
for
Mixing
Zones
Historically,
States
have
relied
on
narrative
criteria
as
a
means
to
provide
baseline
protection
for
water
quality,
to
address
toxicity
from
combinations
of
pollutants
or
unknown
pollutants
through
whole
effluent
toxicity
testing
and
limits,
and
to
control
pollutants
for
which
there
are
no
chemical­
specific
criteria
available.
EPA
has
consistently
maintained
that
prevention
of
nuisance
conditions
(
e.
g.,
materials
that
will
settle
to
form
objectionable
deposits,
floating
debris,
oil,
scum,
foam
and
other
matter,
toxic
conditions,
etc.),
through
the
application
of
narrative
criteria,
apply
to
all
waters,
at
all
times,
including
mixing
zones.
Despite
this
long­
standing
policy,
EPA
is
unaware
if,
in
practice,
States
and
Tribes
have
had
any
difficulty
ensuring
the
maintenance
of
these
narrative
criteria
within
mixing
zones.
EPA
is
interested
in
comment
which
might
identify
any
instances
where
the
application
of
narrative
criteria
has
created
difficulties
for
States
and
Tribes
implementing
these
provisions
in
mixing
zones.
In
addition,
EPA
has
traditionally
interpreted
these
narrative
``
free
froms''
as
including
a
prohibition
against
lethality
in
all
waters,
including
within
mixing
zones.
However,
lethality
is
a
non­
conservative
endpoint
for
measuring
toxicity.
Section
101(
a)(
3)
of
the
CWA
establishes
a
goal
of
prohibiting
``
the
discharge
of
toxic
pollutants
in
toxic
amounts''
which
could
be
interpreted
as
applying
to
chronic
as
well
as
acute
toxicity.
EPA
guidance
on
appropriate
water
quality
within
mixing
zones
also
recommends
that
``
the
total
time­
toxicity
exposure
history
must
not
cause
deleterious
effects
in
exposed
populations
of
important
species,
including
postexposure
effects''
(
EPA,
1973).
EPA
is
considering
how
such
an
interpretation
(
i.
e.,
applying
chronic
toxicity
endpoints
to
water
quality
within
a
mixing
zone)
could
be
implemented
in
the
context
of
the
application
of
narrative
criteria
within
a
mixing
zone.
Guidance
developed
by
EPA
in
1985
(
TSD)
established
a
rationale
for
allowing
zones­
of­
initial­
dilution
(
ZIDs)
or
acute
mixing
zones.
That
guidance
limited
the
use
of
ZIDs
to
extremely
small
areas
of
the
receiving
water
under
limited
conditions
and
to
discharges
using
rapid
diffusers
which
produce
effluent
discharge
velocities
exceeding
10
feet
per
second.
That
guidance
was
premised
on
the
rationale
that
organisms
would
be
physically
precluded
from
maintaining
a
position
within
the
ZID,
thus
preventing
lethal
exposures.
Benthic
and
sessile
organisms
were
also
protected
where
ZID
placement
was
controlled
and
directed
away
from
such
critical
areas
(
e.
g.,
near
shore,
shallows,
etc.).
In
addition,
EPA
reasoned,
high
rate
diffusers
achieve
compliance
with
both
acute
and
chronic
criteria
within
a
smaller
area,
utilizing
less
receiving
water
volume
for
dilution
than
other
discharge
designs.
Consequently,
high
rate
diffusers
are
believed
to
provide
greater
protection
of
water
quality
by
their
rapid
dispersion
of
effluent
within
a
smaller
volume
of
surface
water.
Where
acute
criteria
are
not
applied
at
the
end­
of­
pipe,
current
EPA
guidance
provides
for
a
number
of
alternative
means
of
protecting
against
lethality
in
a
mixing
zone,
even
in
situations
that
do
not
rely
on
high
rate
diffusers.
Alternatives
to
requiring
compliance
with
acute
criteria
at
the
end­
of­
pipe
or
employing
a
high­
rate
diffuser
to
ensure
compliance
``
within
a
very
short
distance
from
the
outfall''
require
a
significant
amount
of
site­
specific
data.
Such
site­
specific
data
could
be
requested
of
NPDES
permit
applicants.
It
is
EPA's
experience
that
the
collection
of
this
kind
of
data
does
not
occur
on
a
routine
basis.
EPA
is
interested
in
public
comment
on
the
relationship
between
ZIDs
or
acute
mixing
zones
and
narrative
criteria
prohibitions
against
lethality
and
States'
and
Tribes'
experiences
with
the
application
of
acute
mixing
zones
under
varying
sitespecific
and
discharge­
specific
conditions.
EPA
is
also
interested
in
comments
on
whether
the
water
quality
benefits
of
using
high
rate
diffusers
justify
potentially
detrimental
effects
on
stream
bed
or
shore
line
habitat.

7.
Mixing
Zones
for
Bioaccumulative
Pollutants
States
and
Tribes
should
exercise
caution
when
evaluating
whether
a
mixing
zone
is
appropriate
in
cases
where
bioaccumulative
pollutants
are
present.
The
impacts
of
bioaccumulative
compounds
may
extend
beyond
the
boundaries
of
a
given
mixing
zone
with
resulting
impairment
of
a
water
body's
designated
uses,
particularly
where
stationary
species
(
e.
g.
shellfish)
are
present,
where
uncertainties
exist
regarding
the
assimilative
capacity
of
a
water
body
or
where
bioaccumulation
in
the
food
chain
is
known
to
be
a
problem.
Sediment
contamination
has
also
become
a
major
concern
in
both
flowing
and
non­
flowing
water
bodies.
Concerns
about
sediment
contamination
require
additional
attention
since
typical
mixing
zone
evaluations
focus
only
on
water
column
toxicity.
The
effects
of
persistent
and
bioaccumulative
pollutants
may
not
be
detected
for
some
distance
from
the
point
of
discharge,
well
outside
the
mixing
zone,
or
possibly
not
in
the
water
column
at
all.
Some
members
of
the
public
have
expressed
concern
regarding
the
use
of
mixing
zones
in
situations
where
bioaccumulative
pollutants
are
present
in
a
discharge
and
have
urged
EPA
to
develop
specific
regulatory
requirements
prohibiting
the
use
of
mixing
zones
where
these
pollutants
are
present.
Mixing
zone
policies
are
developed
to
address
complete
and
incomplete
mixing
conditions
associated
with
point
source
discharges.
These
policies
identify
whether
mixing
zones
are
allowed
and
define
how
a
State
or
Tribe
will
limit
the
amount
of
surface
water
allocated
to
mixing
under
a
variety
of
circumstances.
These
circumstances
include
considerations
specific
to
the
effluent
and
pollutants
discharged
(
e.
g.,
toxicity,
solubility)
and
to
the
water
body
receiving
the
waste
(
e.
g.,
shallow,
flowing
or
non­
flowing,
high
flow
or
low
flow,
critical
habitat).
The
potential
for
bioaccumulation
problems
can
depend
on
a
number
of
site­
specific
factors
and
the
use
of
mixing
zones
for
bioaccumulative
pollutants
may
be
best
dealt
with
on
a
site­
or
basin­
specific
basis.
EPA's
mixing
zone
guidance
emphasizes
that
the
determination
by
a
State
or
Tribe
that
a
mixing
zone
is
appropriate
must
be
preceded
by
a
separate
determination
that
there
is
available
assimilative
capacity
in
the
receiving
water.
Localized
water
quality
concerns
are
to
be
balanced
with
the
larger
scale
issue
of
overall
pollutant
loading
to
the
entire
water
body
or
segment.
Perhaps
concerns
about
the
fate
and
transport
of
bioaccumulative
pollutants
are
more
effectively
addressed
under
total
maximum
daily
load
(
TMDL)
development
and
determinations
of
assimilative
capacity
which
incorporate
information
on
water
36792
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Register
/
Vol.
63,
No.
129
/
Tuesday,
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7,
1998
/
Proposed
Rules
column,
sediment
and
tissue
contamination.
EPA
is
considering
the
appropriateness
of
using
mixing
zones
when
controlling
for
bioaccumulative
pollutants.
As
discussed
in
more
detail
in
Section
C
of
this
Notice,
EPA
has
recently
developed
methodologies
for
deriving
sediment
quality
criteria
for
non­
ionic
organics
and
metals
and
has
proposed
sediment
quality
criteria
for
five
organics.
In
addition,
EPA
is
working
on
implementation
procedures
or
a
``
user's
guide''
for
these
sediment
criteria
which
will
address
risk
management
decisions
such
as
the
application
of
mixing
zones.
The
regulatory
impact
of
special
restrictions
on
mixing
zones
for
a
particular
family
of
pollutants
is
largely
determined
by
how
that
family
of
pollutants
is
defined
within
the
regulation.
The
issue
of
definition
of
bioaccumulative
pollutants
is
also
addressed
in
the
discussion
of
water
quality
criteria
in
Section
C
of
this
notice.
In
its
Great
Lakes
Guidance,
EPA
established
a
twelve
year
phase
out
of
mixing
zones
for
existing
discharges
of
bioaccumulative
chemicals
of
concern
(
BCCs)
in
the
Great
Lakes
Basin
and
a
ban
on
such
mixing
zones
for
new
discharges
(
effective
March
1997).
The
Great
Lakes
Guidance
also
allowed
States
and
Tribes
to
establish
limited
exceptions
to
the
mixing
zone
phase­
out
for
existing
discharges
based
on
water
conservation
or
economic
and
technical
considerations.
The
general
prohibition
on
mixing
zones
for
BCCs
was
established
largely
because
of
the
persistent
and
toxic
nature
of
even
minute
amounts
of
BCCs
in
the
environment;
an
effect
amplified
in
the
Great
Lakes
by
the
tendency
of
the
Lakes
to
act
as
``
sinks''
for
pollutants
discharged
to
the
Great
Lakes
Basin.
In
addition,
there
are
documented
problems
with
effects
of
BCCs
in
Great
Lakes
waters
(
e.
g.,
contamination
of
Great
Lakes
salmonid
sport
fisheries
with
PCBs
and
Basin­
wide
mercury
contamination).
The
Great
Lakes
Guidance
provision
phasing
out
mixing
zones
for
BCCs
reflected
the
Agency's
thinking
that,
in
general,
mixing
zone
allowances
for
BCCs
are
not
appropriate.
On
June
6,
1997,
the
United
States
Court
of
Appeals
for
the
District
of
Columbia
Circuit
issued
its
decision
in
American
Iron
and
Steel
Institute,
et
al.
v.
EPA,
115
F.
3d
979
(
D.
C.
Cir.
1997).
The
Court's
decision
upheld
the
Great
Lakes
Guidance
on
all
but
three
issues.
One
of
these
three
issues
was
the
phase
out
of
on
mixing
zones
for
BCCs.
Specifically,
the
Court
vacated
the
final
Guidance
insofar
as
it
would
eliminate
mixing
zones
for
bioaccumulative
chemicals
of
concern
(
BCCs).
While
the
Court
acknowledged
the
possibility
of
environmental
benefit
of
the
mixing
zone
provisions,
the
Court
found
that
EPA
failed
to
show
that
the
provisions
were
justified
in
light
of
the
costs.
EPA
continues
to
support
elimination
of
mixing
zones
for
BCCs
within
the
Great
Lakes
Basin
wherever
it
is
technically
and
economically
feasible
to
do
so.
Thus,
EPA
intends
to
propose
reinstating
this
provision
in
the
near
future.

8.
Stream
Design
Flow
Policies
States
and
Tribes
typically
identify,
within
their
water
quality
standards,
stream
design
flow
conditions
to
implement
numeric
water
quality
criteria.
The
stream
flow
conditions
are
typically
expressed
as
predictable
low
flow
conditions
below
which
numeric
water
quality
criteria
do
not
apply.
Examples
of
commonly
used
stream
design
flows
include:
the
lowest
seven
consecutive
day
average
stream
flow
that
has
the
annual
probability
of
occurring
once
in
ten
years
(
7Q10);
the
lowest
single
day
stream
flow
that
has
the
annual
probability
of
occurring
once
in
ten
years
(
1Q10);
and
the
harmonic
mean
stream
flow.
The
stream
design
flows
typically
employed
with
aquatic
life
criteria
(
i.
e.,
7Q10
and
1Q10),
sometimes
referred
to
as
critical
low
flows
or
drought
flows,
are
intended
to
define
stream
flow
conditions
at
and
above
which
the
designated
uses
are
presumed
to
exist
and
applicable
numeric
water
quality
criteria
must
be
met
in
order
for
those
uses
to
be
attained.
The
underlying
concept
is
that
these
low
flow
events
are
a
part
of
the
dynamic
hydrologic
character
of
all
flowing
water
bodies.
Low
flow
conditions
present
special
challenges
to
the
integrity
of
the
aquatic
community.
Even
under
these
low
flow
conditions,
however,
the
long­
term
beneficial
use
could
be
maintained
unless
toxic
conditions
stress
the
aquatic
community
beyond
its
ability
to
tolerate
and
recover.
In
practice,
stream
design
flows
serve
several
purposes
in
addition
to
defining
the
minimum
stream
flows
below
which
numeric
water
quality
criteria
do
not
apply.
Many
States
and
Tribes
have
used
the
stream
design
flows,
or
fractions
thereof,
to
define
the
amount
of
stream
flow
that
can
be
assumed
to
always
be
available
to
dilute
effluent.
Under
rapid
and
complete
mixing
conditions,
the
entire
stream
design
flow
is
used
as
the
basis
for
determining
permit
limits.
That
is,
no
mixing
zone
is
necessary.
Under
slow
or
incomplete
mixing
conditions,
where
a
mixing
zone
is
necessary,
fractions
of
stream
design
flow
are
used
to
calculate
assimilative
capacity
on
which
permit
limits
can
be
based;
in
other
words,
to
crudely
define
the
mixing
zone.
Often
this
default
approach
is
used
by
regulatory
agencies
in
response
to
limited
resources,
lack
of
site­
specific
information
and
the
time
pressures
of
permit
reissuance.
This
default
approach
to
defining
the
mixing
zone
is,
in
EPA's
view,
acceptable
as
long
as
the
mixing
of
the
effluent
in
the
receiving
water
occurs
away
from
critical
areas
and
the
amount
of
dilution
provided
is
conservative
for
a
broad
range
of
possible
effluent/
receiving
water
dilution
scenarios.
However,
where
a
complete
mixing
assumption
does
not
hold
true,
such
as
where
an
effluent
plume
does
not
disperse
quickly,
and
too
much
of
the
receiving
water
is
allocated
for
dilution,
this
default
assumption
approach
will
not
ensure
attainment
of
water
quality
standards
because
numeric
water
quality
criteria
will
be
exceeded
in
a
larger
area
than
anticipated
(
outside
the
regulatory
mixing
zone).
The
default
use
of
fractions
of
stream
design
flows
instead
of
more
exacting
mixing
zone
determinations
is
not
always
appropriate.
In
some
instances,
the
effluent
plume
may
never
fully
mix
with
the
specified
amount
of
receiving
water,
resulting
in
plumes
where
criteria
are
exceeded
extending
far
beyond
what
may
be
considered
protective
of
designated
uses
or
allowed
under
standards.
EPA
has
recommended
that
site­
specific
information
on
the
mixing
characteristics
of
a
discharge
be
collected
to
verify
the
level
of
protection
assumed
to
be
provided
to
a
water
body
using
default
mixing
zone
provisions.
EPA
believes
it
is
important
for
individual
States
and
Tribes
to
make
consistent
dilution
allowance
decisions
from
one
site
to
the
next.
Requiring
States
and
Tribes,
as
part
of
their
water
quality
standards,
to
specify
how
dilution
allowances
under
complete
and
incomplete
mix
situations
will
be
established
may
be
an
appropriate
way
to
ensure
consistent
decision­
making.
To
best
define
dilution
allowances
for
implementing
water
quality
standards,
it
is
useful
to
define
both
stream
design
flows
and
effluent
design
flows.
In
particular,
a
distinction
should
be
made
between
the
stream
design
flows
to
be
used
for
different
ambient
water
quality
criteria
(
e.
g.,
aquatic
life
acute,
aquatic
life
chronic,
human
health
carcinogen).
In
addition,
effluent
design
flows
may
vary
in
some
cases
based
upon
seasonal
changes
or
production
cycles.
Stream
design
flows
may
be
applied
as
a
maximum
dilution
allowance
or
adjusted
in
individual
cases
based
on
36793
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
any
stream­
specific
or
pollutant­
specific
considerations.
Stream
design
flows,
if
they
are
used,
must
correspond
to
the
duration
and
frequency
components
of
the
ambient
water
quality
criteria
contained
in
the
State
or
Tribal
water
quality
standards.
Currently,
States
and
Tribes
must
justify
the
scientific
validity
of
their
stream
design
flow
policies
where
they
differ
from
EPA's
recommendations.
States
and
Tribes
may
also
establish
specific
guidelines
for
restricting
dilution
allowances
in
individual
cases
(
e.
g.,
States
and
Tribes
may
adopt
special
restrictions
on
dilution
allowances
for
human
health
criteria
where
a
discharge
is
within
2
miles
of
a
drinking
water
intake).
EPA's
Great
Lakes
Guidance
and
its
Technical
Support
Document
for
Water
Quality­
Based
Toxics
Control
identify
acute
and
chronic
stream
design
flows
to
be
utilized
in
drafting
permit
limits.
The
Guidance
establishes
a
7Q10
or
4­
day,
3­
year
biologically­
based
stream
design
flow
for
implementation
of
the
aquatic
life
criterion
continuous
concentration
(
chronic
criteria);
a
1Q10
for
the
implementation
of
the
aquatic
life
criterion
maximum
concentration
(
acute
criteria);
harmonic
mean
flow
for
implementation
of
human
health
criteria;
and
a
90Q10
for
the
implementation
of
wildlife
criteria.
In
cases
where
complete
and
rapid
mixing
of
effluent
with
receiving
water
does
not
occur,
site­
specific
mixing
determinations
must
be
made.
Although
the
selection
of
fractions
of
stream
design
flows
for
the
assignment
of
available
dilution
for
point
source
discharges
does
affect
the
size
of
the
regulatory
mixing
zone,
such
default
assignments
are
not
hydrologically
linked
to
the
actual
behavior
of
the
effluent
plume
in
the
receiving
water,
may
not
protect
swimming
and
drifting
organisms
or
sessile
or
benthic
organisms
and
are
not
equivalent
to
a
mixing
analysis.
There
may
be
other
instances
where
the
reliance
on
a
fixed
percentage
of
flow
or
cross­
sectional
area
of
the
receiving
stream
in
lieu
of
an
actual
mixing
analysis
may
not
reflect
the
mixing
behavior
of
an
effluent.
In
some
high
dilution
situations,
there
may
be
more
rapid
dilution
occurring
than
is
assumed
in
dilution
calculations.
If
complete
and
instantaneous
mixing
actually
occurs,
using
less
than
100%
of
the
design
flow
can
be
a
means
of
accounting
for
situations
where
the
actual
assimilative
capacity
of
the
water
body
is
unknown.
States
and
Tribes
typically
determine
water
body
assimilative
capacity
based
on
ambient
background
concentration
of
a
pollutant,
when
data
on
such
concentrations
is
available.
The
assimilative
capacity
is
the
difference
between
the
background
level
of
a
pollutant
and
the
highest
level
that
would
comply
with
the
water
quality
criterion.
Where
information
on
all
sources
of
a
given
contaminant
to
a
specific
water
body
is
incomplete,
or
where
the
State
or
Tribe
wishes
to
reserve
assimilative
capacity
for
the
future,
States
and
Tribes
should
allocate
less
than
100%
of
the
assimilative
capacity
of
that
water
body
at
design
flow
by
utilizing
less
than
100%
of
the
design
flow
for
dilution.
EPA
is
interested
in
comment
addressing
the
use
of
these
stream
design
flows
or
fractions
of
stream
design
flows
in
setting
mixing
zones
and
in
reserving
assimilative
capacity
in
a
water
body.
The
Great
Lakes
Guidance
allows
States
and
Tribes
to
use
default
assumptions
for
available
dilution
in
the
absence
of
site­
specific
mixing
data.
The
default
dilution
assumption
for
open
waters
(
e.
g.,
lakes)
provides
for
ten­
toone
dilution.
The
Guidance
also
allows
for
a
demonstration
to
determine
actual
mixing
zone
water
quality,
size,
placement
and
behavior.
Under
the
Guidance,
for
open
waters,
in
no
case
can
mixing
zone
size
exceed
that
area
in
which
discharge­
induced
mixing
occurs.
As
a
default,
the
Guidance
restricts
the
mixing
zone
for
protection
of
aquatic
life
from
acute
effects
(
i.
e.,
the
dilution
allowed
in
calculating
limits
based
on
an
acute
aquatic
life
criterion
or
CMC)
to
2
parts
receiving
water
to
1
part
effluent,
at
water
body
design
flow
or
volume.
As
a
default
for
implementing
criteria
for
the
protection
of
aquatic
life
from
chronic
effects
(
CCC)
in
flowing
waters
(
e.
g.,
rivers
and
streams),
the
Great
Lakes
Guidance
allows
States
and
Tribes
to
use
up
to
25%
of
the
design
flow
for
dilution.
If
a
site­
specific
mixing
analysis
is
performed,
a
larger
mixing
zone
may
be
established.
Mixing
zones
for
acute
aquatic
life
criteria
in
flowing
waters
are
limited
to
the
final
acute
value
or
FAV
(
2
´
 
the
acute
criterion)
just
as
in
open
waters.
EPA
is
interested
in
comment
on
whether
this
FAV
default
``
cap''
approach
is
appropriate
for
waters
outside
the
Great
Lakes
Basin.
As
stated
above,
the
Great
Lakes
Guidance
allows
increases
above
the
default
mixing
zone
allowances
when
site­
specific
mixing
zone
analyses
are
conducted.
These
demonstrations
compile
data
on
the
mixing
behavior
of
the
effluent
at
a
particular
site
(
e.
g.,
the
size,
shape
and
location
of
the
mixing
zone).
The
Guidance
also
required
that
mixing
zones
maintain
existing
and
designated
uses
and
comply
with
narrative
water
quality
criteria
(
e.
g.,
``
free
froms'').
The
Great
Lakes
Guidance
also
specifies
that
mixing
zones
may
not
jeopardize
the
existence
of
threatened
or
endangered
species
or
their
critical
habitat.
EPA
advocates
the
watershed
approach
to
water
quality
protection.
For
the
water
quality
standards
program,
the
emphasis
has
been
toward
refinement
of
designated
uses
and
incorporation
of
new
and
emerging
sophisticated
and
integrated
analytical
tools
as
a
means
to
better
characterize
the
ecological
condition
of
water
resources
and
more
effectively
protect
designated
uses
(
see
section
I(
A)
``
General
Purpose
and
Vision''
of
this
document).
The
development
and
implementation
of
mixing
zone
policies
by
States
and
Tribes
constitutes
risk
management
at
the
sub­
watershed
level.
EPA
has
consistently
emphasized
the
need
to
ensure
that
State
and
Tribal
mixing
zone
provisions
protect
the
designated
uses
of
receiving
waters.
Site­
specific
data
collected
through
a
mixing
zone
analysis
will
ensure
that
designated
uses
will
be
protected
the
loss
of
ecological
integrity
from
the
discharge
of
effluents
will
be
prevented.
An
emphasis
on
the
protection
of
designated
uses
and
maintenance
of
ecological
integrity
is
essential
to
the
watershed
approach.
The
watershed
approach
requires
increased
sitespecific
information
on
local
aquatic
systems
and
an
assessment
of
the
impact
of
all
discharges
to
local
ecosystems.
The
watershed
approach
also
depends
upon
the
meaningful
involvement
of
local
communities
in
risk
management
decision­
making.
Explicit,
clear
implementation
policies
provide
the
public
with
the
information
necessary
to
understand
decisions
being
made
by
regulators
and
the
impact
of
those
decisions
on
local
resources.

Request
for
Comments
on
Mixing
Zone
Policies
and
Implementation
Procedures
EPA
requests
comment
on
the
following
questions:
1.
Should
the
regulation
be
changed
to
expressly
require
States
and
Tribes
to
include
a
statement
in
their
water
quality
standards
indicating
whether
mixing
zones
are
allowed?
2.
Should
the
regulation
be
changed
to
expressly
require
States
and
Tribes
to
specify
procedures
by
which
mixing
zone
decisions
for
individual
discharges
would
be
made?
3.
Should
the
regulation
be
modified
to
identify
the
minimum
requirements
or
elements
for
State
and
Tribal
mixing
zone
policies
(
including
size,
location,
and
methodologies)?
36794
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
4.
Consistent
with
current
EPA
policy,
should
the
regulation
explicitly
require
narrative
criteria
to
apply
in
mixing
zones?
5.
Should
the
regulation
require
States
and
Tribes
to
identify
in
their
mixing
zone
provisions
what
minimum
water
quality
conditions
are
required
within
mixing
zones?
6.
Are
there
any
circumstances,
types
of
pollutants
or
water
body
types
(
e.
g.,
wet
weather
discharges)
where
mixing
zones
should
be
restricted
or
prohibited?
7.
Should
mixing
zones
for
bioaccumulative
pollutants
be
prohibited?
If
so,
under
what
circumstances?
Should
such
prohibitions
be
addressed
on
a
water
body­
or
basin­
specific
basis?
Should
EPA
allow
exceptions
to
any
such
prohibitions?
8.
Should
the
regulation
require
States
and
Tribes
to
specify
procedures
and
decision
criteria
for
evaluating
complete
and
incomplete
mixing?
9.
Should
the
regulation
require
different
mixing
zone/
dilution
procedures
for
complete
and
incompletely
mixed
situations?
10.
Should
an
assumption
of
rapid
and
complete
mixing
within
State
and
Tribal
implementation
procedures
be
prohibited
except
where
a
defensible
technical
rationale
is
included
in
each
site­
specific
determination?
11.
Should
the
regulation
explicitly
allow
the
use
of
default
mixing
zone
assumptions
based
on
fractions
of
stream
design
flow
in
the
absence
of
site­
specific
data?
12.
Should
the
regulation
be
clarified,
consistent
with
current
EPA
policy,
to
require
States
and
Tribes
to
identify
the
water
body
design
flows
or
volumes
upon
which
their
water
quality
standards
are
based?

F.
Wetlands
as
Waters
of
the
United
States
The
current
water
quality
standards
regulation
contains
no
definition
of
``
waters
of
the
United
States,''
although
this
term
is
used
in
the
definition
of
``
water
quality
standards.''
The
phrase
``
waters
of
the
United
States''
has
been
defined
elsewhere
in
Federal
regulations,
including
regulations
governing
the
National
Pollutant
Discharge
Elimination
System
(
NPDES).
That
definition
at
40
CFR
122.2
includes
wetlands
whose
use,
degradation
or
destruction
could
affect
interstate
commerce
and
wetlands
adjacent
to
other
waters
of
the
U.
S.
However,
because
this
definition
does
not
appear
in
40
CFR
131,
some
have
questioned
whether
Part
131
applies
to
wetlands.
EPA's
position
is
that
the
Part
131
regulations
do
apply
to
wetlands.
EPA
is
considering
including
the
definition
for
``
waters
of
the
United
States''
under
the
standards
regulation
as
well,
or,
at
a
minimum,
cross­
referencing
the
definition
at
40
CFR
122.2
as
a
means
of
clarifying
that
the
existing
regulation
applies
to
wetlands
that
fall
within
the
definition
of
waters
of
the
United
States.
Currently,
EPA
plans
no
review
or
revision
of
the
existing
definition
of
``
waters
of
the
United
States''
as
part
of
any
revision
of
the
water
quality
standards
regulation.
Therefore,
under
the
ANPRM,
EPA
is
interested
in
comment
limited
to
whether
the
existing
definition
should
be
included
within
the
standards
regulation
in
some
form.
EPA
believes
that
some
States
or
Tribes
may
not
be
providing
the
same
protection
to
wetlands
that
they
provide
to
other
surface
waters,
including
designation
of
attainable
uses
consistent
with
the
CWA
and
assignment
of
protective
water
quality
criteria.
Therefore,
EPA
wishes
to
emphasize
that
wetlands
require
the
same
protection
under
water
quality
standards
as
other
waters
of
the
U.
S.
Section
303
of
the
CWA
requires
the
protection
of
all
``
waters
of
the
U.
S.''
under
standards.
Addition
of
the
definition
of
``
waters
of
the
U.
S.''
under
a
revision
of
the
regulations
would
not
constitute
an
expansion
of
authority
or
application,
but
merely
a
clarification
of
those
requirements
already
contained
within
the
CWA.
Treatment
of
jurisdictional
issues
would
not
be
affected
by
such
a
revision,
including
treatment
of
waters
constructed
as
waste
treatment
systems
(
e.
g.,
wetlands
constructed
for
wastewater
treatment).
Notwithstanding
protection
of
wetlands
under
other
provisions
of
the
CWA
(
e.
g.,
Section
404),
Section
303
clearly
establishes
a
baseline
level
of
protection
applicable
to
all
waters.
Further,
it
is
this
treatment
under
water
quality
standards
which
provides
for
protection
of
wetlands
as
applied
under
Section
404.
Necessary
components
of
water
quality
standards
for
wetlands
are
designated
uses
and
criteria,
as
defined
in
40
CFR
131.6.
EPA
recognizes
that
uses
and
criteria
should
reflect
the
unique
physical,
chemical
and
biological
characteristics
of
wetlands.
States
and
Tribes
are
encouraged
to
develop
and
adopt
appropriate
classification
systems
which
provide
protection
of
beneficial
uses
of
wetlands
through
the
application
of
physical,
chemical
and
biological
criteria.
EPA
also
recognizes
that
certain
parameters,
conditions
or
even
pollutants
may
be
most
appropriately
addressed
by
criteria
which
specifically
reflect
differences
between
wetlands
and
other
surface
waters.

Request
for
Comments
on
Wetlands
EPA
requests
public
comment
on
the
following
questions:
1.
Should
``
waters
of
the
United
States''
be
defined
in
the
water
quality
standards
regulation?
2.
Should
EPA
provide
explicit
reference
in
the
regulation
to
the
applicability
of
water
quality
standards
to
wetlands?
3.
Do
the
current
regulation
and
existing
guidance
provide
the
necessary
regulatory
clarity,
technical
tools,
and
incentives
for
States
and
Tribes
to
develop
appropriate
standards
for
wetlands?
4.
Are
specific
programmatic
changes
needed
to
facilitate
the
development
of
water
quality
standards
for
wetlands?

G.
Independent
Application
Policy
1.
Introduction
Section
101(
a)
of
the
Clean
Water
Act
states:
``
The
objective
of
this
Act
is
to
restore
and
maintain
the
chemical,
physical,
and
biological
integrity
of
the
Nation's
waters.''
To
this
end,
States
and
Tribes
designate
single
or
multiple
uses
for
their
waters
including
aquatic
life
protection.
For
the
purposes
of
assessing
the
extent
to
which
aquatic
life
is
protected
and
whether
actions
to
protect
aquatic
life
are
needed,
the
CWA
requires
that
States
and
Tribes
adopt
water
quality
criteria
necessary
to
support
designated
uses.
For
waters
where
aquatic
life
protection
is
an
applicable
designated
use,
the
extension
of
the
CWA
requires
States
and
Tribes
to
adopt
criteria
protective
of
aquatic
life.
Taken
together,
chemical,
physical,
and
biological
integrity
define
the
overall
ecological
integrity
of
an
aquatic
ecosystem.
Over
the
years,
EPA,
States
and
Tribes
have
developed
various
tools
to
assess
the
extent
to
which
water
quality
attains
this
objective.
These
tools
have
been
developed
to
build
on
and
support
the
capabilities
of
each
other
and
provide
a
comprehensive
set
of
elements
necessary
for
implementing
water
quality
standards
and
achieving
the
objective
of
the
CWA.
EPA
policy
and
guidance
recommends
that
States
and
Tribes
use
chemical­
specific,
toxicity,
and
biological
criteria
to
monitor
and
protect
designated
uses.
In
1991,
EPA
established
its
policy
on
independent
application
(
U.
S.
EPA,
transmittal
memorandum
of
final
policy
on
biological
assessment
and
criteria
from
Tudor
Davies
to
Regions,
June
19,
1991).
EPA's
independent
application
policy
speaks
to
how
assessments
based
36795
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
on
these
three
kinds
of
criteria
are
to
be
integrated
into
all
forms
of
water
quality
management
decision­
making.
EPA's
independent
application
policy
and
the
ensuing
discussion
here
address
the
issue
of
how
the
three
different
kinds
of
assessments
are
interpreted
only
in
the
context
of
protection
of
aquatic
life
and
aquatic
life
uses
and
not
in
the
context
of
protection
of
human
health
or
wildlife.
With
the
advent
of
different
ways
of
assessing
the
health
of
aquatic
systems
comes
the
possibility
of
conflicting
results.
To
address
such
conflicts,
EPA
developed
the
policy
of
independent
application.
Independent
application
states
that
where
different
types
of
monitoring
data
are
available
for
assessment
of
whether
a
water
body
is
attaining
aquatic
life
uses
or
for
identifying
the
potential
of
pollution
sources
to
cause
or
contribute
to
non
attainment
of
aquatic
life
uses,
any
one
assessment
is
sufficient
to
identify
an
existing
or
potential
impact/
impairment,
and
no
one
assessment
can
be
used
to
override
a
finding
of
existing
or
potential
impact
or
impairment
based
on
another
assessment.
The
independent
application
policy
takes
into
account
that
each
assessment
provides
unique
insights
into
the
integrity
and
health
of
an
aquatic
system.
In
addition,
each
assessment
approach
has
differing
strengths
and
limitations,
and
assesses
different
stressors
and
their
effects,
or
potential
effects,
on
aquatic
systems.
For
example,
while
biological
assessments
can
provide
information
in
determining
the
cumulative
effect
of
past
or
current
impacts
from
multiple
stressors,
these
assessments
may
be
limited
in
their
ability
to
predict,
and
therefore
prevent,
impacts.
While
chemical­
specific
assessments
are
useful
to
evaluate
and
predict
ecosystem
impacts
from
single
pollutants,
chemical­
specific
methods
are
unable
to
assess
the
combined
interactions
of
pollutants
(
e.
g.,
additivity).
Similar
to
biological
assessments,
toxicity
testing
provides
a
means
of
evaluating
the
aggregate
toxic
effects
of
pollutants,
and
like
chemical
assessments,
can
also
be
used
when
testing
effluent
to
predict
single
chemical
impacts.
One
of
the
limitations
of
toxicity
testing,
however,
is
that
the
identification
of
pollutants
causing
toxicity
is
not
always
possible
or
costeffective
Each
of
these
three
assessment
approaches
relies
on
different
kinds
of
water
quality
data,
measures
different
endpoints
and,
in
practice,
will
be
interpreted
in
the
context
of
implementing
a
water
quality
management
program
that
includes
assessment
and
pollution
control.
EPA's
policy
on
independent
application
is
based
on
the
premise
that
any
valid,
representative
data
indicating
an
actual
or
projected
water
quality
impairment
must
not
be
ignored
when
determining
the
appropriate
action
to
be
taken.
Independent
application
recognizes
the
strengths
and
limitations
of
all
three
assessment
approaches.
The
next
three
sections
briefly
describe
three
assessment
approaches
(
biological,
toxicological
and
chemical)
one
could
likely
be
evaluating
when
using
independent
application.
Those
three
sections
are
then
followed
by
two
parallel
discussions
on
different
uses
of
water
quality
data.
One
use
relates
to
the
NPDES
permits
program
to
determine
whether
a
permit
must
contain
water
quality­
based
chemical
or
toxicity
limits,
and
what
those
numeric
limits
should
be.
The
other
relates
to
the
use
of
such
data
to
evaluate
the
quality,
or
condition,
of
waters
under
the
CWA
section
305(
b)
and
303(
d)
programs.
At
the
core
of
both
of
these
contexts
is
the
question
``
are
the
present
applicable
water
quality
criteria
complete
and
appropriate
for
the
water
body,
and
how
are
we
to
measure
attainment
of
the
present
or
future
criteria
that
apply
to
any
water
body
in
question?''
Thus,
in
its
most
basic
sense,
independent
application
remains
a
water
quality
standards
question.
Any
changes
to
or
clarifications
of
the
policy
on
independent
application
must
therefore
be
considered
first
under
the
rubric
of
water
quality
standards
and
then
in
the
separate
contexts
of
permitting
and
water
quality
evaluation
which
are
based
on
water
quality
standards.
States
and
Tribes
routinely
determine
whether
water
bodies
are
attaining
their
designated
uses
and
whether
existing
pollution
controls
adequately
protect
those
uses.
Some
States
and
Tribes
have
recommended
to
EPA
that
it
modify
the
independent
application
policy.
Currently,
EPA's
policy
of
independent
application
is
the
same
for
both
NPDES
permitting
and
water
quality
assessment
programs.
However,
EPA
recognizes
that
each
of
the
programs
has
somewhat
different
data
needs
and
attributes.
Therefore,
today's
notice
separates
the
two
distinct
uses
of
independent
application
to
better
focus
the
discussion.
a.
Biological
Assessments.
Biological
assessments
are
based
on
quantifying
differences
between
expected
biological
community
attributes
such
as
structure,
function
and
condition
(
known
as
a
reference
condition)
and
the
biological
community
attributes
found
at
a
specific
site
being
evaluated.
The
extent
to
which
the
community
at
the
site
deviates
from
the
reference
conditions
is
indicative
of
the
degree
of
impairment
at
the
specific
site.
The
strength
of
biological
assessments
is
their
ability
to
provide
a
direct
measure
of
the
health
of
aquatic
ecosystems.
Biological
assessments
are
also
able
to
detect
nonchemical
impacts
(
e.
g.,
habitat
loss,
sedimentation,
temperature
effects)
in
addition
to
chemical
toxicity
problems.
States
and
Tribes
that
use
biological
assessments,
use
them
primarily
to
evaluate
the
ecological
condition
of
water
bodies
and
to
determine
whether
a
water
body
is
healthy,
threatened,
or
impaired
(
i.
e.,
aquatic
life
use
attainment
decisions).
In
some
instances,
States
and
Tribes
have
used
biological
assessments
to
establish
monitoring
requirements
in
an
NPDES
permit,
but
generally,
most
use
bioassessments
to
make
non­
regulatory,
general,
water
resource
management
decisions.
Data
from
a
biological
assessment
can
be
compared
to
a
gradient
that
shows
the
reference
(
expected)
conditions
without
impairment
on
one
end
and
the
worst
situation
on
the
other.
States
and
Tribes
generally
use
the
results
to
determine
whether
additional
measures
are
needed
to
protect
the
water
segment,
or
determine
how
close
to
attainment
an
impaired
system
is.
Biological
assessments
can
also
play
a
role
in
linking
impairment
to
causative
agents.
This
link
is
often
not
definitive,
but
can
be
very
useful
in
helping
to
identify
the
causes
and
sources
of
many
impairments.
Some
States
and
Tribes
have
used
indicator
species
or
groups
to
distinguish
effects
of
toxicity
from
effects
of
organic
enrichment.
For
example,
one
State
documented
that
a
midgefly
larvae
is
found
to
be
predominant
in
areas
contaminated
by
electroplating
or
metal
wastes.
Although
biological
assessments
cannot
be
used
to
predict
conditions
in
a
mathematical
modeling
sense,
over
time
they
can
be
used
to
indicate
the
direction
of
change,
and
the
degree
of
that
change,
in
the
condition
at
a
particular
site.
This
information,
where
it
is
based
on
enough
data
using
relatively
sensitive
appropriate
metrics,
can
be
very
valuable
in
deciding
whether
the
current
condition
is
likely
to
be
maintained
under
similar
conditions
in
the
future,
or
whether
there
are
early
warning
signs
of
biological
impacts
giving
reason
to
believe
that
additional
regulatory
actions
may
be
needed
to
prevent
water
quality
standards
impairment.
Regulatory
actions
that
are
a
response
to
measured
change
in
biological
condition
will
tend
to
be
restorative
more
than
preventative
(
i.
e.,
36796
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
once
biological
impact
is
measured,
by
definition,
that
impact
was
not
prevented).
Although,
slight
changes
that
are
not
sufficient
to
render
a
water
in
non­
attainment
of
its
aquatic
life
use,
can
provide
early
warning
of
potentially
more
significant
future
changes.
In
contrast,
as
noted
above,
regulatory
actions
based
on
impairment
predicted,
for
example
via
a
chemical­
specific
modeling
analysis,
tend
to
be
preventative.
To
the
extent
that
conditions
in
a
water
body
do
change
(
e.
g.,
flow),
biological
assessments
do
not
reveal
potential
future
impacts
under
other
exposure
conditions
(
e.
g.,
low­
flow
conditions).
Programmatically,
there
are
concerns
regarding
quality
assurance
and
quality
control
for
various
biological
assessment
techniques
since
they
have
yet
to
be
promulgated,
or
standardized,
in
any
EPA
programs.
This
is
mainly
due
to
the
site­
specific
nature
of
biological
assessments.
Implementation
of
biological
criteria
is
also
discussed
in
section
(
B)
of
this
notice.
b.
Toxicological
Assessments.
Toxicological
assessments
are
conducted
by
exposing
aquatic
organisms
to
effluent
or
ambient
water
samples
or
sediment
samples
in
a
laboratory
and
determining
the
effects
on
the
exposed
organisms.
Because
toxicity
assessments
evaluate
the
overall
effects
of
the
entire
suite
of
constituents
in
a
sample,
they
are
ideal
for
identifying
interactions
between
chemicals
that
can
alter
the
expected
effects
of
individual
chemicals
on
exposed
organisms.
Toxicity
assessments
also
capture
the
toxic
effects
of
chemical
compounds
not
commonly
monitored
for
or
for
which
chemical­
specific
criteria
are
lacking.
In
addition,
because
it
can
be
manipulated
in
the
laboratory,
toxicity
testing
can
predict
the
likelihood
of
ecological
impacts
before
they
occur.
This
allows
safeguards
to
be
put
into
place
before
an
actual
ecological
impact
occurs.
Toxicity
assessments
are
usually
limited
by
the
variety
of
species
that
can
be
cultured
in
the
laboratory.
While
numerous
test
species
can
be
used
to
evaluate
the
toxicity
of
individual
samples,
typically
only
two
or
three
species
are
used
for
such
tests.
By
comparison,
eight
different
families
are
required
to
develop
chemical­
specific
criteria.
For
some
toxicants,
the
broader
sensitivity
range
provided
by
testing
eight
different
families
is
particularly
important,
for
example,
where
the
mode
of
toxicity
action
is
specific
(
e.
g.,
pesticides).
Identifying
the
cause
of
toxicity
can,
in
some
situations,
be
a
difficult,
expensive,
and
lengthy
process.
Another
consideration
is
that
toxicity
testing
does
not
detect
habitat
perturbations
which
can
greatly
limit
a
water
resources
aquatic
life
use.
Finally,
toxicity
assessments
are
only
valid
for
as
long
as
all
the
sample
testing
conditions
remain
the
same.
Ambient
conditions
affecting
toxicity
may
change
over
time
necessitating
additional
testing.
c.
Chemical
Assessments.
Chemical
assessments
measure
individual
chemical
constituents
(
e.
g.,
copper,
lead)
or
chemical
conditions
(
e.
g.,
pH,
temperature,
hardness,
organic
content)
in
a
medium.
Chemical
assessments
may
be
performed
on
effluent
or
ambient
water
samples
or
sediment
samples.
Chemical
analyses
are
usually
simpler
to
conduct
and
generally
less
expensive
than
toxicity
assessments
or
bioassessments,
particularly
if
there
are
only
a
few
chemicals
of
concern,
but
the
information
from
these
tests
may
provide
limited
insight
into
the
ecological
condition
of
the
water
body.
If
information
is
available
on
pollutant
persistence
and
degradation,
modeling
can
be
used
to
predict
pollutant
fate
and
transport
under
a
variety
of
exposure
scenarios.
Further,
chemical­
specific
assessments
are
ideal
for
predicting
the
likelihood
of
ecological
impacts
where
they
may
not
yet
have
occurred
either
because
a
proposed
activity
affecting
water
quality
has
not
been
implemented
or
critical
exposure
conditions
have
not
yet
been
experienced
by
the
aquatic
community.
For
these
reasons,
regulatory
actions
based
on
chemicalspecific
assessment
can
be
preventative
as
well
as
restorative.
Basing
regulatory
and
management
decisions
on
chemical
assessment
of
water
quality
is
an
important
and
proven
aspect
of
water
quality
assessment
and
protection.
However,
as
an
indirect
measure
of
aquatic
health,
one
of
the
principal
limitations
to
chemical
assessments
is
dependence
upon
chemical­
specific
benchmarks
(
such
as
chemical
water
quality
criteria)
for
determining
whether
water
quality
is
suitable
or
unsuitable
for
attaining
and
maintaining
aquatic
life
uses.
As
noted
elsewhere
in
this
notice,
stressors
other
than
specific
chemicals
in
a
water
body
are
often
a
significant
or
even
predominant
cause
of
nonattainment
of
aquatic
life
uses.
EPA's
current
thinking
is
that
complete
reliance
on
chemicalspecific
assessments
of
water
quality
is
too
narrow
of
a
focus
and
fails
to
provide
information
on
other
important
ecosystem
stressors.
In
addition,
as
noted
elsewhere
in
this
notice,
there
are
currently
water
quality
criteria
for
the
protection
of
aquatic
life
for
31
chemicals.
There
are
tens
of
thousands
of
chemicals
discharged
into
surface
waters.
(
Note,
however,
that
the
chemicals
for
which
there
are
criteria
tend
to
be
the
most
frequently
discharged).
Thus
there
is
the
added
problem
of
too
few
criteria
and
too
many
chemicals,
making
it
inappropriate
to
rely
exclusively
on
the
chemical­
specific
approach.
Another
substantial
limitation
of
chemicalspecific
benchmarks
is
that
for
a
given
site,
the
benchmarks
that
are
used,
may
not
be
the
best
that
are
available
to
reflect
the
level
of
protection
applicable
at
the
site.
For
example,
site­
specific
aquatic
life
criteria
are
generally
different
(
higher
or
lower)
than
the
national
recommendations
for
the
same
chemical.
And
yet
absent
site­
specific
criteria,
the
national
recommendations
are
often
used.

2.
Independent
Application
and
Water
Quality
Assessments
a.
Independent
Application.
States
and
Tribes
often
collect
or
have
access
to
monitoring
data
that
measure
the
concentration
of
specific
chemicals
in
an
effluent
or
water
body,
the
level
of
toxicity
present
in
ambient
water
or
discharges
to
a
water
body
and/
or
the
biological
community
composition
within
a
water
body.
These
data
are
then
interpreted
by
comparing
them
to
reference
conditions
or
criteria
to
determine
whether
or
not
aquatic
life
uses
are
attained.
EPA's
1991
policy
on
independent
application
was
explicit
about
the
use
of
independent
application
in
water
quality
programs:
``
This
policy,
therefore,
states
that
appropriate
action
should
be
taken
when
any
one
of
the
three
types
of
assessment
determines
that
the
standard
is
not
attained.
States
and
Tribes
are
encouraged
to
implement
and
integrate
all
three
approaches
into
their
water
quality
programs
and
apply
them
in
combination
or
independently
as
sitespecific
conditions
and
assessment
objectives
dictate.''
In
implementing
this
policy,
EPA
recommends
that
data
from
the
three
assessment
approaches
be
applied
independently
in
water
quality
programs
since
each
method
provides
unique
and
distinct
information
on
the
characteristics
of
the
water
body.
In
other
words,
EPA
recommends
that
differences
in
assessment
results
be
resolved
in
one
of
two
ways:
either
presume
an
adverse
impact
when
any
one
source
of
data
indicates
an
adverse
impact,
or
reevaluate
the
complete
data
set
and
modify
the
applicable
criteria
to
account
for
the
new
site­
specific
information.
Given
EPA's
mission
to
protect
the
environment
and
absent
definitive
data
to
demonstrate
that
an
assessment
is
in
error
or
otherwise
biased,
EPA
presumes
36797
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
where
an
assessment
indicates
impairment,
that
assessment
is
valid.
In
the
context
of
applying
the
independent
application
policy
to
the
assessment
of
water
bodies,
there
are
two
distinct
CWA
provisions
to
consider:
(
1)
section
305(
b),
which
requires
States
and
Tribes
to
report
to
EPA
and
EPA
to
report
to
Congress
a
description
of
the
quality
of
the
Nation's
waters;
and
(
2)
section
303(
d),
which
relates
to
identification
of
waters
where
technology­
based
limitations
and
other
required
controls
are
not
stringent
enough
to
ensure
that
applicable
water
quality
standards
will
be
attained
and
maintained.
With
respect
to
the
section
305(
b)
Report,
the
CWA
broadly
calls
for
States
and
Tribes
to
assess
water
quality
conditions
in
a
biennial
report.
EPA
transmits
these
reports
to
Congress,
together
with
an
analysis
of
the
reports
describing
water
quality
conditions.
Because
these
are
water
quality
assessment
reports
that
States
and
Tribes
submit
to
EPA,
and
not
specific
regulatory
decisions,
there
may
be
sufficient
flexibility
in
the
interpretation
of
data
to
allow
a
more
integrated
approach
to
evaluating
limitations
and
inconsistencies
in
the
interpretation
of
data
produced
under
various
approaches.
For
example,
direct
assessments
of
the
condition
of
the
waters
(
e.
g.,
biological
assessment)
could
be
weighted
more
heavily
than
indirect
measurements
(
e.
g.,
chemical
and
toxicity).
With
respect
to
section
303(
d),
the
CWA
and
EPA's
implementing
regulations
require
States
and
Tribes
to
identify
those
waters
for
which
technology­
based
limitations
and
other
required
controls
are
not
stringent
enough
to
achieve
water
quality
standards
applicable
to
such
waters.
See
303(
d)(
1)(
A),
40
CFR
130.7(
b)(
1).
When
identifying
waters
pursuant
to
303(
d),
the
methods
used
to
determine
nonattainment
of
standards
for
water
quality
reporting
under
305(
b)
should
also
be
used.
However,
water
bodies
are
eliminated
from
303(
d)
list
consideration
if
technology­
based
controls
or
other
required
Federal,
State,
Tribal
or
local
requirements
will
result
in
the
attainment
of
applicable
water
quality
standards.
TMDLS
developed
to
secure
restoration
of
designated
uses
are
largely
dependent
upon
chemical
criteria
and
assessment
to
define
acceptable
pollutant
loadings.
The
question
arises
as
to
whether
States
and
Tribes
have
the
flexibility
to
exclude
a
water
body
from
305(
b)
reports
and
303(
d),
i.
e.,
conclude
that
the
designated
use
was
protected,
even
in
the
face
of
data
indicating
one
or
more
excursions
of
the
applicable
chemical­
specific
water
quality
criteria.
EPA
would
like
to
consider
possible
mechanisms
under
the
existing
CWA
and
the
legal
theories
supporting
them
to
address
these
questions.
As
with
determining
the
need
for
regulatory
controls
(
permit
limits),
similar
data
evaluation
issues
face
States,
Tribes
and
EPA
in
performing
water
body
assessments
for
purposes
of
sections
303(
d)
and
305(
b)
of
the
CWA.
With
respect
to
such
assessments,
EPA's
goals
for
States
and
Tribes
are
twofold:
(
1)
to
encourage
the
use
of
chemical,
toxicological,
physical
and
biological
data
in
making
water
body
assessments;
and,
(
2)
to
ensure
that
the
data
are
interpreted
and
reported
in
a
consistent
and
scientifically
defensible
manner
so
that
documents
such
as
the
305(
b)
report
to
Congress
provide
valid
and
useful
information
on
the
status
of
the
Nation's
waters
as
a
whole,
irrespective
of
State
or
Tribal
boundaries.
EPA
recognizes
that
there
may
be
instances
where
these
goals
appear
to
be
in
conflict.
It
is
possible
that
as
States
and
Tribes
implement
biological
assessment
programs,
they
may
identify
new
areas
of
impact
that
were
previously
undetected
using
other
assessment
techniques
and
that
this
may
lead
to
a
reluctance
on
the
part
of
States
and
Tribes
to
develop
the
expertise
necessary
to
conduct
biological
assessments.
Although
this
tendency
is
contrary
to
the
goals
and
objectives
of
the
CWA,
the
fact
is
that
addressing
new
and
previously
unaddressed
threats
to
surface
water
quality
places
additional
strain
on
already
limited
State
and
Tribal
resources.
Some
also
feel
that
adherence
to
a
strict
independent
application
policy
for
assessment
purposes
discourages
the
use
of
more
data
than
minimally
needed
to
make
an
aquatic
life
use
assessment.
In
most
cases,
the
minimal
amount
of
data
would
be
a
chemical
grab
sample
for
a
few
water
quality
characteristics
such
as
temperature,
pH,
BOD,
or
dissolved
oxygen.
Collecting
minimal
data
for
assessment
reporting
is
much
easier
and
less
resource
intensive
for
States
and
Tribes
that
are
required
to
increase
their
reporting
coverage,
and
these
States
and
Tribes
would
not
have
to
deal
with
differing
interpretation
of
assessment
results.
However,
EPA
believes
that
placement
of
waters
on
section
303(
d)
and
section
305(
b)
lists
should
be
based
on
broad
thorough
assessment
data,
not
on
limited
and
narrow
data.
The
former
will
help
ensure
that
targeted
water
quality
controls
and
management
actions
are
appropriate
and
will
result
in
water
quality
standards
attainment;
the
latter
can
result
in
significant
outlays
of
State
and
Tribal
resources
targeted
on
waters
where
water
quality
problems
are
not
well
understood.
EPA
is
considering
how
best
to
obtain
accurate,
high­
quality
assessment
data
and
how
to
reconcile
differences
between
assessments
conducted
using
different
techniques
in
a
manner
that
fosters
consistency
and
remains
scientifically
defensible.
b.
Alternatives
to
Independent
Application.
There
is
considerable
sentiment
among
various
stakeholder
groups
that
there
is
a
need
to
better
incorporate
more
comprehensive
data,
particularly
biological
data,
into
the
water
quality
assessment
framework
described
above
and
that
doing
so
will
facilitate
collection
and
use
of
more
integrated
and
insightful
water
quality
data.
EPA
shares
this
view.
Some
have
used
the
term
``
weight­
of­
evidence''
to
describe
an
alternative
to
the
present
EPA
policy
of
independent
application
that
could
facilitate
integration
of
chemical,
physical,
toxicological
and
biological
data
into
the
assessment
program.
However,
EPA
recognizes
that
individuals'
views
about
the
meaning
of
the
term
``
weight
of
evidence''
vary
considerably
and
this
variation
should
be
addressed.
The
term
``
weight­
ofevidence
has
been
interpreted
by
some
to
mean
that
one
approach
to
assessment,
e.
g.,
biological,
could
routinely
be
used
to
override
conclusions
drawn
using
another
assessment
technique,
e.
g.,
chemical.
EPA
believes
that
approach
is
hierarchical,
not
a
weight­
of­
evidence
approach.
EPA's
position
is
that
each
approach,
chemical,
toxicological,
physical
and
biological
has
inherent
strengths
and
limitations
and
that
all
valid
water
quality
assessment
data
generated
under
any
of
these
approaches
should
be
used
in
assessing
the
health
of
aquatic
ecosystems,
in
ways
that
adequately
take
into
account
the
strengths
and
limitations
of
each
approach.
EPA's
current
thinking
is
that
as
forms
of
water
quality
assessment
data
have
become
broader
(
chemical,
physical,
biological
and
toxicological),
and
as
the
amount
of
such
data
increases,
the
water
quality
standards
and
assessment
programs
need
to
facilitate
continued
collection
and
use
of
such
data,
and
that
doing
so
will
lead
to
more
thorough
water
quality
assessments,
more
insightful
water
quality
criteria,
and
better
descriptions
of
aquatic
life
designated
uses.
EPA
would
not
support
an
approach
that
could
lead
to
collecting
fewer
and
narrower
water
quality
data
by
States,
Tribes
and
dischargers.
On
the
contrary,
36798
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
EPA's
current
thinking
is
that
to
employ
a
weight­
of­
evidence
approach,
a
State
or
Tribe
(
or
EPA)
would
need
to
have
a
comprehensive
set
of
water
quality
data
to
evaluate
the
chemical,
physical,
toxicological
and
biological
conditions
in
a
water
and
to
conduct
ecological
impact
assessment
to
determine
the
precise
causes
of
impacts
(
chemical,
physical,
biological,
and
toxicological)
and
how
best
to
address
them.
EPA's
current
thinking
is
that
the
most
appropriate
context
for
using
a
weightof
evidence
approach
would
be
in
establishing
criteria.
In
addition,
as
discussed
below,
EPA
is
interested
in
evaluating
the
use
of
a
weight­
ofevidence
approach
for
assessment
and
reporting
under
section
305(
b)
of
the
CWA.
However,
once
the
criteria
are
established
for
a
water
body,
the
assessment
for
purposes
of
listing
under
section
303(
d)
of
the
CWA
and
permitting
under
NPDES,
must
be
based
on
all
applicable
water
quality
criteria.
EPA's
305(
b)
reporting
guidelines
interpret
the
independent
application
policy
to
apply
to
aquatic
life
use
assessments
for
State
305(
b)
reports,
not
just
to
permitting
for
protecting
waters
due
to
reasonable
potential
to
violate
water
quality
standards.
This
policy
helps
protect
against
dismissing
valuable
information
when
evaluating
aquatic
life
use
attainment,
particularly
in
detecting
impairment.
This
approach
is
most
protective
when
there
is
limited
data
available
and
when
there
is
no
documentation
on
the
rigor
of
the
assessment.
EPA
is
concerned
that
lack
of
information
can
provide
false
confidence
about
the
health
of
the
nation's
water
bodies.
However,
EPA
is
now
developing
a
comprehensive
approach
for
conducting
aquatic
life
use
assessments
which
integrates
chemical,
toxicological,
physical
and
biological
data,
and
includes
consideration
of
the
strengths
and
limitations
of
the
assessment
methods
and
the
data.
This
shift
toward
more
integrated
assessments
is
reflected
in
EPA's
most
recent
guidance
to
the
States
and
Tribes
on
conducting
305(
b)
assessments,
particularly
in
determining
nonattainment
(
EPA's
Guidelines
for
Preparation
of
the
1996
State
Water
Quality
Assessments
(
305(
b))
reports,
EPA
841
B
 
95
 
001)
and
is
the
primary
focus
of
the
Office
of
Water's
Criteria
and
Standards
program
Plan.
The
1996
305(
b)
guidelines
are
consistent
with
the
Policy
on
Independent
Application
while
incorporating
a
weight­
ofevidence
approach
in
determining
the
degree
of
impairment
(
partial
or
nonsupport).
The
1996
guidelines
do
not
allow
for
a
finding
of
full
support,
or
attainment,
of
aquatic
life
use
when
there
are
differences
in
assessment
results.
Under
certain
circumstances,
however,
the
guidelines
allow
for
the
possibility
of
a
finding
of
partial
support,
even
where
results
of
different
assessments
are
not
fully
consistent.
Generally,
in
assessing
severity
of
impairment,
assessments
based
on
data
with
high
levels
of
information,
or
rigor,
should
be
weighted
more
heavily
than
those
based
on
data
with
low
levels
of
information,
and,
rigorous
biological
data
should
be
weighted
more
heavily
than
other
data
types.
EPA
recommends
that
the
results
of
biological
assessments,
especially
those
with
high
levels
of
information,
be
the
basis
for
the
overall
aquatic
life
use
support
(
ALUS)
determination
if
the
data
indicate
impairment.
This
is
because
rigorous
biological
data
provide
a
direct
measure
of
the
status
of
the
aquatic
biota
and
detect
the
cumulative
impact
of
multiple
stressors
on
the
aquatic
community,
including
new
or
previously
undetected
stressors.
Determining
the
level
of
information
or
rigor
for
each
assessment
is
a
critical
component
of
the
305(
b)
guidelines
on
making
an
ALUS
determination.
The
levels
of
information
allow
characterization
of
the
quality
and
the
temporal
and
spatial
coverage
of
the
data
States
and
Tribes
utilize
to
conduct
their
use
assessments.
Levels
of
information
are
identified
for
assessments
based
on
biological,
physical,
chemical
and
toxicological
data.
For
example,
measures
of
the
condition
of
the
aquatic
community
using
indices
incorporating
multiple
assemblages
of
aquatic
organisms
based
on
a
regional
reference
approach
would
rate
higher
than
a
measure
of
a
single
organism
or
single
metric
or
annual
fixed
station
monitoring
for
chemical
contaminants.
Likewise,
three
years
of
bi­
monthly
fixed
station
monitoring
for
chemical
contaminants
would
rate
higher
than
annual
fixed
station
monitoring
for
the
same
chemicals
or
a
biological
measure
of
a
single
organism
or
metric.
Understanding
the
breadth
and
robustness
of
the
assessment
methods
used
in
evaluating
whether
a
water
body
is
attaining
its
designated
aquatic
life
use
is
important
information
for
EPA,
the
States,
and
the
public.
In
the
future,
EPA
will
be
evaluating
possible
scenarios
where
a
finding
of
full
support
could
be
justified
despite
differences
in
assessment
results.
For
example,
a
finding
of
full
support
based
on
rigorous
biological
data
may
be
justified
despite
differences
with
chemical
specific
assessment
results
depending
on
the
magnitude
and
frequency
of
the
chemical
exceedances
and
the
applicability
of
the
chemical
benchmark
to
the
site.
It
will
be
important
for
EPA
to
carefully
evaluate
such
potential
scenarios
and
to
define
the
adequate
data
requirements
and
level
of
rigor
necessary
to
support
a
determination
of
full
support
despite
differences
in
assessment
results.
Equally
important,
EPA
will
need
to
carefully
consider
the
ramifications
of
such
determinations
on
other
parts
of
its
water
program.
Another
permutation
of
the
weight­
ofevidence
approach
to
aquatic
life
use
assessment
is
to
establish
a
hierarchy
in
which
the
results
of
one
method
could
always
override
the
other
methods
should
there
be
difference
in
assessment
results.
Most
frequently,
it
has
been
argued
that
biological
assessments
could
always
override
chemical
assessments
in
determining
whether
the
designated
aquatic
life
uses
are
being
attained.
Some
prefer
this
approach
because
a
rigorous
biological
assessment
provides
a
direct
measure
of
existing
ecosystem
health
and
have
expressed
concern
that
the
policy
of
independent
application
oversimplifies
the
relationship
among
different
data
sets
used
to
assess
current
water
quality
conditions.
Proponents
of
this
approach
contend
that
biological
assessment
is
an
integrated
assessment
that
incorporates
the
information
that
would
be
provided
through
either
chemical
or
toxicological
assessments
into
a
single,
comprehensive
measure
of
aquatic
ecosystem
health.
Some
advocate
the
acceptance
of
rigorous
biological
data
as
the
ultimate
arbiter
of
aquatic
life
use
attainment.
They
also
suggest
that,
at
least
with
respect
to
current
aquatic
life
condition
assessments,
chemical,
toxicological,
and
biological
assessments
are
not
independent;
each
measures
the
same
assessment
endpoint,
but
from
different
stressors.
These
proponents
say
that
biological
assessment
is
the
only
assessment
approach
available
to
integrate
and
reflect
current
effects
from
chemical,
toxicological,
physical,
and
nonpoint
source
stressors.
Because
of
this
they
suggest
that
rigorous
data
based
on
biological
assessments
and
criteria
should
automatically
supersede
data
from
other
sources
when
determining
aquatic
life
use
attainment.
Some
contend
that
if
biological
data
demonstrate
that
biological
criteria
are
attained,
then
the
water
body
is
attaining
its
designated
use,
even
if
other
monitoring
data
such
as
toxicological
or
chemical
data
demonstrate
an
excursion,
or
potential
for
an
excursion,
above
a
water
quality
criterion.
Some
also
contend
that
rigorous
biological
assessments
should
be
used
36799
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
to
supersede
assessments
based
on
predicted
impacts
such
as
water
quality
modeling
and
wasteload
allocations
in
decision
making
for
aquatic
life
use
assessments.
One
concern
with
this
perspective
is
that
non­
rigorous
biological
assessments
could
be
used
in
such
situations,
though
EPA
has
305(
b)
reporting
guidance
which
suggest
minimum
quality
of
biological
assessments
that
could
also
be
used
for
these
situations.
In
this
guidance,
EPA
recommends
using
more
than
one
assemblage
(
fish
and/
or
macro
invertebrates/
and
or
algae),
several
index
values
or
metrics
(
multiple
metrics),
an
index
period
for
sampling,
and
ecoregional
or
other
biogeographic
regional
calibration.
EPA
agrees
that
rigorous
biological
assessment
based
on
adequate
sitespecific
data
is
a
direct
assessment
of
aquatic
ecosystem
health,
unlike
chemical
and
toxicity
assessments.
However,
biological
assessments
are
less
well
suited
for
use
in
preventing
water
quality
impacts
and
will
only
reflect
impacts
once
they
have
occurred.
Though
this
may
be
less
of
a
concern
in
waters
with
a
relatively
constant
level
of
discharge
where
there
has
been
ongoing
biological
assessment.
A
second
objective
of
water
quality
assessment
under
the
CWA,
beyond
assessing
when
the
aquatic
life
use
is
impaired,
is
assessing
when
stressors,
if
left
unchecked,
will
cause
impairment.
As
discussed
above,
the
chemical­
specific
approach
is
especially
strong
for
use
in
identifying
and
predicting
impacts
before
they
happen.
EPA
is
concerned
that
the
use
of
a
hierarchical
approach
may
ignore
or
undermine
valuable
information,
whether
that
information
is
biological,
physical,
chemical,
or
toxicological,
and
not
trigger
the
appropriate
action
to
address
the
inconsistency
(
e.
g.,
evaluation
of
existing
criteria
and
development
of
site­
specific
criteria).
Therefore,
EPA
does
not
support
such
an
approach.
EPA
has
a
number
of
concerns
with
any
approach
wherein
data
from
certain
assessment
techniques
may
be
automatically
superseded
by
those
from
others.
A
primary
concern
is
the
failure
of
such
a
system
to
make
use
of
all
valuable
information.
In
all
cases,
criteria,
whether
chemical­
specific,
toxicological,
physical
or
biological,
are
derived
with
the
intent
of
identifying
a
threshold
beyond
which
unacceptable
impacts
to
aquatic
ecosystems
are
expected
to
occur.
In
most
cases,
it
is
expected
that
when
different
assessment
techniques
(
i.
e.,
chemical
and
biological)
are
used
for
determining
attainment
of
aquatic
life
uses,
the
techniques
will
yield
similar
results
if
all
are
done
rigorously.
In
addition,
it
is
expected
to
be
rare
for
chemical
assessments
to
indicate
nonattainment
where
biological
assessment
indicate
attainment;
analyses
conducted
by
the
State
of
Ohio
confirm
this.
(
See
Yoder,
C.,
``
Answering
Some
Concerns
about
Biological
Criteria
Based
on
Experiences
in
Ohio.'').
However,
it
is
also
expected
that
in
certain
cases,
different
assessment
techniques
will
result
in
different
determinations
of
aquatic
life
use
attainment
due
to
the
fact
that
each
technique
evaluates
aquatic
life
use
attainment
differently,
and
some
take
into
account
safety
factors
for
ensuring
future
attainment
while
others
focus
on
the
current
status
of
the
condition.
When
different
assessment
techniques
that
are
intended
to
measure
similar
environmental
endpoints
and
yield
comparable
results
fail
to
do
so,
it
may
be
an
indication
that
assumptions
underlying
the
criteria
are
not
valid
for
a
particular
site,
or
that
the
data
were
not
rigorous.
While
in
some
cases
it
may
be
appropriate
to
weigh
one
set
of
data
more
heavily
than
another
in
making
a
use
attainment
determination,
in
others
it
may
be
preferable
to
take
advantage
of
such
circumstances
as
opportunities
to
validate
and
cross­
check
criteria,
making
adjustments
as
indicated
by
the
data.
This
could
result,
for
example,
in
an
adjustment
to
a
specific
chemical
criterion
in
a
particular
water
if
rigorous
biological
assessment
indicated
that
such
an
adjustment
is
appropriate.
Such
information
is
also
useful
to
EPA
in
improving
national
criteria
development
methodologies.
Lack
of
comparability
in
assessments
is
also
a
concern
for
either
a
weight­
ofevidence
or
a
hierarchical
approach
to
aquatic
life
use
assessments.
Therefore,
it
is
important
that
there
be
a
common
understanding
between
States,
Tribes
and
EPA
as
to
how
conflicts
in
data
interpretation
will
be
resolved
in
evaluating
and
reporting
water
quality.
Developing
comparable
methods
to
handle
data
conflicts
will
make
comparisons
between
States
and
Tribes
more
useful,
such
as
in
305(
b)
reports.
Without
a
consistent
approach
to
resolving
data
conflicts,
assessments
of
water
quality
data
at
the
national
level
becomes
problematic.
EPA's
policy
of
independent
application
is
one
way
of
providing
a
consistent
and
defensible
framework
for
data
evaluation
in
order
to
minimize
this
problem.

Request
for
Comments
on
integration
of
data
in
water
quality
assessments
EPA
is
interested
in
comment
on
how
chemical,
physical,
toxicological,
and
biological
assessments
can
be
effectively
incorporated
and
implemented
in
State
and
Tribal
water
quality
standards
programs
to
achieve
the
goals
of
the
CWA.
EPA
requests
comments
on
the
following
questions:
1.
How
can
conflicting
interpretations
of
water
quality
assessment
data
be
reconciled
in
a
scientifically
defensible
manner?
Should
each
kind
of
water
quality
information
stand
alone
as
a
scientific
measure
of
current
water
quality
conditions
and
ecosystem
health?
Alternatively,
are
there
situations
where
one
type
of
data
should
be
given
more
weight
than
another
in
determining
use
attainment?
2.
How
should
States
and
Tribes
evaluate
water
quality
information
generated
using
chemical,
toxicological,
physical,
and
biological
methods
when
determining
use
attainment
status?
3.
When
interpretation
of
water
quality
data
indicate
inconsistent
results,
what
factors
(
i.
e.,
data
richness),
if
any,
should
EPA
consider
relevant
to
determining
``
appropriate
actions''?
4.
Should
EPA
explicitly
address
in
the
water
quality
standards
regulation
the
evaluation
assessments
using
chemical,
toxicological,
physical
and
biological
assessment
methods?
5.
Should
an
approach
be
instituted
where
independent
application
may
be
relaxed
for
water
quality
assessment
strategies
and
decisions
when
a
State
or
Tribe
has
established
a
comprehensive
monitoring
and
assessment
program
including
biological
monitoring
and
assessment?
What
guidelines
should
be
used
to
evaluate
a
State
or
Tribal
biological
monitoring
and
assessment
program?
6.
How
should
the
policy
of
independent
application
address
the
distinction
between
situations
where
adequate
rigorous
data
are
available
for
each
assessment
technique
and
situations
where
available
data
for
one
or
more
of
the
assessment
techniques
are
limited
in
quantity
or
quality?
Specifically,
should
the
policy
be
modified
to
more
explicitly
encourage
or
require,
where
feasible,
additional
monitoring,
particularly
where
limited
data
are
to
be
used
as
a
basis
for
regulatory
action?

3.
Independent
Application
and
NPDES
Permitting
a.
Independent
Application.
Clean
Water
Act
section
101(
a)
states
that
``[
t]
he
objective
of
this
Act
is
to
restore
and
maintain
the
chemical,
physical,
and
biological
integrity
of
the
Nation's
waters.''
In
the
context
of
implementing
water
quality­
based
pollution
controls
under
the
NPDES
program,
EPA
has
maintained
that
independent
36800
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
application
of
all
forms
of
water
quality
assessment
data
(
i.
e.,
chemical,
physical,
toxicological
and
biological)
is
clearly
consistent
with
this
objective.
In
addition
to
restoring
impaired
surface
waters,
water
quality­
based
pollution
controls
are
often
implemented
to
prevent
water
quality
standards
impairment
that
projections
indicate
will
occur
in
the
absence
of
the
water
quality­
based
controls.
Thus,
predictive
assessment
tools
are
necessary
and
have
proven
effective
in
the
NPDES
water
quality­
based
program.
An
important
question
in
NPDES
permitting
that
EPA's
policy
of
independent
application
was
specifically
developed
to
address
is:
how
should
differences
in
interpretation
of
water
quality
data
produced
using
different
water
quality
assessment
techniques
for
aquatic
life
uses
be
reconciled?
Upon
examination
of
this
question,
EPA
determined
that
differences
in
data
interpretation
do
not
necessarily
equate
to
contradictory
results.
Different
assessment
results
may
be
complementary
since
the
different
approaches
can
measure
different
aspects
of
water
quality.
For
aquatic
life
uses,
all
three
data
types
(
chemical,
toxicological,
and
biological)
provide
useful
information
and
should
be
used
to
protect
designated
uses.
Because
the
different
types
of
assessments
often
focus
on
different
aspects
of
aquatic
community
health
and
each
has
different
strengths
and
limitations,
it
is
possible
that
any
one
type
of
assessment
may
fail
to
detect
impairments,
or
potential
impairments
of
the
designated
use.
For
that
reason,
EPA's
current
interpretation
of
the
CWA
and
its
implementing
regulations
is
that
all
three
types
of
data
(
chemical,
toxicological,
and
biological)
should
be
used
when
evaluating
the
reasonable
potential
for
a
discharge
to
cause
or
contribute
to
an
excursion
above
a
water
quality
criterion
and,
if
one
approach
indicates
that
water
quality
is,
or
will
be,
impacted,
the
results
from
the
other
methods
could
not
be
used
to
refute
that
finding.
Under
this
approach,
where
``
reasonable
potential''
is
found,
the
NPDES
permitting
authorities
must
take
appropriate
``
actions;''
that
is,
implement
water
quality­
based
effluent
limits
that
are
derived
from
and
comply
with
the
applicable
water
quality
criteria.
These
``
actions''
may
also
include
additional
monitoring
to
determine
whether
a
problem
exists,
or
to
derive
site­
specific
criteria
if
a
particular
criterion
is
found
to
be
inaccurate
for
a
site.
The
policy
on
independent
application
is
presented
in
further
detail
in
Chapter
1
of
EPA's
1991
Technical
Support
Document
for
Water
Quality­
based
Toxics
Control
(
TSD)
and
in
chapter
1
of
EPA's
Water
Quality
Standards
Handbook
 
Second
Edition,
September
1994
(
Handbook)
(
both
documents
cited
above).
In
the
Great
Lakes
Guidance,
EPA
maintained
its
policy
of
independent
application
with
respect
to
determining
the
need
for
water
quality­
based
effluent
limits,
making
it
an
explicit
implementation
requirement
in
the
Great
Lakes
States.
The
Guidance,
in
Appendix
F,
Procedure
5,
section
F
``
Other
Applicable
Conditions,''
states
``
When
determining
whether
WQBELs
are
necessary,
information
from
chemical­
specific,
whole
effluent
toxicity
and
biological
assessments
shall
be
considered
independently.''
(
40
CFR
Part
132,
Appendix
F,
Procedure
5,
Section
F.
3.).
In
the
permitting
context,
EPA's
independent
application
policy
reflects
language
in
sections
301(
b)(
1)(
C)
and
303
of
the
CWA
and
permit
regulations
implementing
these
statutory
provisions
at
40
CFR
122.44(
d).
Pursuant
to
section
303
of
the
CWA,
States
and
Tribes
adopt
chemical­
specific
numeric
criteria
and
toxicity
criteria
as
part
of
their
water
quality
standards.
Section
303(
c)(
2)(
B)
of
the
CWA
further
requires
States
and
Tribes
to
adopt,
as
part
of
their
water
quality
standards,
numeric
criteria
for
toxic
pollutants
for
which
EPA
has
published
guidance
under
section
304(
a),
and
whose
discharge
or
presence
in
State
or
Tribal
waters
could
reasonably
be
expected
to
interfere
with
the
designated
uses
adopted
by
the
State
or
Tribe
for
those
waters.
(
As
discussed
elsewhere
in
this
document,
all
States
and
Tribes
have
narrative
water
quality
criteria
as
well.)
Section
301(
b)(
1)(
C)
of
the
CWA
requires
effluent
limitations
in
NPDES
permits
that
are
``
necessary
to
meet
water
quality
standards''
or
necessary
to
``
implement
any
applicable
water
quality
standard.''
Consistent
with
this
provision,
EPA's
permitting
regulations
at
40
CFR
122.44(
d)
require
that
effluent
limits
be
imposed
where
the
discharge
has
the
``
reasonable
potential''
to
cause
or
contribute
to
an
excursion
above
water
quality
criteria
and
specifically
describe
how
those
limits
are
to
be
expressed
(
e.
g.,
chemical­
specific
versus
WET
limits).
Therefore,
once
a
numeric
(
or
narrative)
water
quality
criterion
becomes
part
of
a
State's
or
Tribe's
water
quality
standards,
and
a
permitting
authority
determines
that
a
discharge
of
a
pollutant
would
have
a
reasonable
potential
to
cause
or
contribute
to
an
excursion
above
the
applicable
numeric
or
narrative
criterion,
the
regulation
requires
that
a
limit
for
that
pollutant
be
established
as
necessary
to
meet
the
water
quality
criterion.
Although
the
CWA
specifies
that
permit
limits
must
meet
water
quality
standards,
it
is
the
permitting
regulations
that
specify
the
factors
that
must
be
considered
when
determining
whether
or
not
there
is
reasonable
potential
to
cause
or
contribute
to
an
excursion
above
a
State
or
Tribal
water
quality
standard,
and
specifically
describe
how
such
limits
are
to
be
expressed.
EPA
regulations
at
40
CFR
122.44(
d)(
1)(
iii)
 
(
v)
describe
the
conditions
under
which
water
qualitybased
effluent
limits
for
specific
chemicals
and
for
whole
effluent
toxicity
are
required
in
NPDES
permits.
While
these
regulations
do
not
specifically
use
the
term
``
independent
application,''
the
concept
is
expressly
laid
out.
These
regulations
require
chemical­
specific
limits
when
the
permitting
authority
determines
there
is
a
reasonable
potential
for
the
discharge
to
cause
or
contribute
to
the
excursion
above
the
chemical­
specific
criterion.
Likewise,
the
regulations
require
limits
for
whole
effluent
toxicity
if
the
permitting
authority
determines
there
is
a
reasonable
potential
for
the
discharge
to
cause
or
contribute
to
the
excursion
above
the
numeric
criterion
for
toxicity
or
narrative
criterion
for
water
quality.
Except
under
limited
circumstances
(
where
the
State
or
Tribe
lacks
a
chemical­
specific
criterion
for
a
pollutant
of
concern),
these
regulations
do
not
allow
a
permitting
authority
to
forgo
one
type
of
limit,
e.
g.
a
chemical
limit,
where
another
type
of
data,
e.
g.,
toxicity,
indicate
no
toxicity.
Instead,
the
two
types
of
data
are
required
to
be
considered
independently.
The
independent
application
policy
provides
a
consistent
and
coherent
protocol
for
resolving
conflicts
in
interpreting
monitoring
data
when
determining
``
reasonable
potential.''
Where
such
conflicts
exist
and
cannot
be
reconciled,
independent
application
directs
States
and
Tribes
to
presume
that
the
data
that
indicate
a
current
or
potential
impact
are
valid
and
to
take
appropriate
steps
to
prevent
or
remediate
the
impact.
The
reconciliation
phase
allows
a
State
or
Tribe
to
gather
additional
or
more
detailed
data
prior
to
taking
regulatory
action.
Data
interpretation
conflicts
may
be
best
addressed
by
identifying
the
cause
of
the
conflict
and
recalibrating
the
models
and
criteria
to
better
reflect
the
newly
acquired
site­
specific
information.
However,
if
the
causes
of
the
data
interpretation
conflicts
cannot
be
resolved,
under
independent
application,
the
State
or
Tribe
must
take
36801
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
action
based
on
the
data
indicating
impairment
or
the
reasonable
potential
for
impairment
of
the
water
body.
EPA
believes
this
procedure
for
addressing
conflicting
interpretations
of
monitoring
data
is
appropriate
for
a
number
of
reasons.
First,
as
stated
earlier,
each
of
the
different
assessment
techniques
monitors
aquatic
ecosystem
health
from
a
slightly
different
perspective.
Consequently,
it
is
entirely
plausible
that
only
one
of
the
assessment
techniques
would
detect
a
real
or
potential
impact.
Second,
assuming
that
the
data
generated
by
the
different
techniques
are
of
comparable
quality
and
relevance,
an
indication
of
a
water
quality
problem
using
any
of
the
techniques
is
sufficient
reason
to
implement
controls.
That
being
the
case,
EPA
believes
the
independent
application
of
water
quality
data
in
determining
when
water
quality­
based
effluent
limits
are
necessary
for
individual
dischargers
is
consistent
with
the
CWA.
Reconciliation
of
data
interpretation
conflicts
allows
flexible
evaluation
of
data.
Once
a
permit
application
is
received
from
a
discharger,
States
and
Tribes
frequently
engage
in
discussions
with
the
discharger
over
the
quality
and
representativeness
of
the
data.
This
period
of
data
review
and
evaluation
is
also
an
ideal
time
for
addressing
any
data
interpretation
conflicts
in
order
to
ensure
that
permitting
decisions
are
defensible
and
the
permit
limits
that
are
imposed
are
necessary
to
protect
designated
uses.
States
and
Tribes,
together
with
permittees,
may
obtain
additional
data
to
verify
earlier
data
or
conduct
timely
studies
to
support
the
development
of
site­
specific
criteria.
Ultimately,
these
site­
specific
criteria
may
serve
as
the
basis
for
a
permit
limit,
or
a
decision
that
it
is
not
necessary
to
limit
a
pollutant
in
a
particular
discharge.
All
of
the
actions
above
are
consistent
with
the
independent
application
policy
and
the
CWA.
Critics
of
EPA's
policy
believe
either
that
data
from
certain
types
of
water
quality
assessments
have
inherently
greater
value
than
data
obtained
by
other
means
or
that,
in
a
sense,
data
quality
and
ecological
significance
should
be
averaged,
such
that
if
data
obtained
from
two
different
assessment
methods
agree
and
data
from
a
third
disagree
with
the
other
two,
the
two
could
``
outweigh''
the
one.
In
either
case,
all
of
the
available
data
would
be
considered
together,
under
the
assumption
that
each
assessment
technique
measures
a
similar
endpoint.
Under
such
an
approach
to
data
evaluation,
limits
on
effluent
toxicity
would
be
appropriate
and
acceptable
as
surrogates
for
chemical­
specific
limits.
Similarly,
biological
assessment
data
that
do
not
indicate
unacceptable
levels
of
impact
on
the
biological
community
could
serve
as
the
basis
for
a
decision
not
to
include
either
chemical­
specific
or
effluent
toxicity
limits
designed
to
support
an
aquatic
life
use
in
a
facility's
discharge
permit.
Proponents
of
this
view
argue
that
independent
application
forces
them
to
take
inappropriate
regulatory
actions
when
faced
with
conflicting
assessment
data.
EPA
does
not
agree
in
principle
with
this
view.
b.
Alternatives
to
Independent
Application.
States,
Tribes,
municipalities,
and
dischargers
have
expressed
concerns
that
the
policy
of
independent
application
results
in
more
protection
than
is
necessary
to
attain
and
maintain
aquatic
life
designated
uses.
Many
express
a
preference
for
an
approach
which
invests
data
obtained
using
certain
assessment
techniques
with
greater
credibility
than
those
obtained
in
other
ways.
Such
an
approach,
as
discussed
above,
is
sometimes
referred
to
as
a
weight­
ofevidence
approach.
Under
such
an
alternative
approach,
assuming
a
high
level
of
confidence
in
all
the
available
data,
one
form
of
data
 
usually
it
is
argued
biological
data
 
would
be
the
ultimate
arbiter
of
whether
water
quality­
based
effluent
limits
are
needed
in
a
discharger's
permit.
To
determine,
for
example,
whether
a
water
qualitybased
effluent
limit
is
needed
for
a
particular
chemical
pollutant,
the
risk
of
adverse
impact
on
the
aquatic
community
would
be
determined
based
on
all
of
the
available
data
relying
more
heavily
on
high
quality,
thorough
biological
data
and
on
the
judgment
of
the
individual
conducting
the
evaluation.
Several
States
and
members
of
the
regulated
community
have
advanced
this
approach
as
preferable
to
EPA's
independent
application
policy,
arguing
that
such
flexibility
to
exercise
judgment
is
appropriate.
EPA's
current
thinking
is
that
it
should
not
promote
an
alternative
approach
to
making
``
reasonable
potential''
decisions
that
places
greater
emphasis
on
biological
data.
Instead,
EPA's
current
thinking
is
that
such
an
evaluation
of
water
quality
and
ecosystem
health
to
determine
the
appropriate
and
applicable
criteria
against
which
discharges
will
be
evaluated
is
most
appropriately
done
during
the
setting
of
the
applicable
criteria
for
a
water
body.
In
that
arena,
it
may
be
feasible
to
use
biological
assessment
as
a
basis
for
determining
the
appropriate
criteria
for
a
given
water
body.
However,
once
the
criteria
are
set,
EPA
believes
that
the
current
regulation
requires
``
reasonable
potential''
evaluations
against
all
the
applicable
criteria,
and
that
the
policy
of
independent
application
in
this
context
is
appropriate.
If
biological
data
indicate
that
designated
uses
are
being
attained
in
spite
of
projected
or
actual
chemicalspecific
criteria
exceedances,
then
additional
site­
specific
analysis
should
be
done
to
ensure
that
controls
are
developed
that
are
necessary
to
adequately
protect
the
water
body
from
use
impairment.
Site­
specific
approaches
could
include
mixing
zone
studies,
more
refined
water
quality
modeling
to
support
wasteload
allocation,
or
the
development
of
sitespecific
criteria.
In
any
case,
chemicalspecific
and
toxicity
criteria
are
proven
and
necessary
bases
of
water
qualitybased
effluent
limits.
In
``
reasonable
potential''
analysis,
chemical­
specific
monitoring
is
usually
focused
on
pollutant
concentrations
in
the
effluent
and
the
projected
ambient
result
of
those
concentrations
being
discharged.
Thus,
this
type
of
analysis
commonly
yields
projected
rather
than
measured
water
quality
impacts.
Where
biological
impact
is
not
detected
using
biological
assessment
methods,
it
is
possible
that
impairment
that
is
projected
and
plausible,
may
simply
have
not
yet
occurred.
However,
where
discharges
to
a
stream
have
been
relatively
constant
over
time
and
there
has
been
ongoing
biological
assessment,
this
would
be
less
of
a
concern.
EPA's
view
is
that
it
would
be
inappropriate
to
ignore
projected
impairment
simply
because
the
impairment
has
not
yet
been
observed
in
the
environment.
An
additional
argument
in
favor
of
retaining
the
independent
application
policy
for
``
reasonable
potential''
determinations
has
to
do
with
the
suitability
of
certain
types
of
data
and
the
unsuitability
of
others
for
certain
applications
within
the
water
pollution
control
program.
For
example,
biological
data
are
not
amenable
in
the
same
way
as
chemical­
specific
data
for
use
in
waste
load
allocations,
load
allocations,
total
maximum
daily
load
calculations
or
antidegradation
reviews.
An
approach
that
would
allow
biological
data
to
negate
a
finding
of
``
reasonable
potential''
would
suggest
possible
site­
specific
inadequacies
of
particular
criteria
without
providing
the
information
needed
to
determine
definitively
whether
or
not
the
criteria
are
appropriate
or
what
any
alternative
criteria
should
be.
As
a
consequence,
a
void
would
be
created
in
the
implementation
of
State
or
Tribal
water
quality
standards
which
would
render
them
unable
to
perform
all
of
their
36802
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
intended
functions.
Proponents
of
independent
application
contend
that
instead
of
discarding
data
and
invalidating
criteria
where
conflicting
interpretations
exist,
an
effort
should
be
made
to
determine
why
the
interpretations
conflict
and
to
refine
the
applicable
criteria
to
better
reflect
the
conditions
found
at
the
site.
Taking
this
step
would
ensure
that,
over
time,
a
full
suite
of
appropriate
criteria
would
be
developed
for
every
site
and
that
all
appropriate
and
necessary
pollution
controls
are
implemented.
In
addition,
such
an
approach
is
consistent
with
the
CWA.
Some
States
and
Tribes
may
be
concerned,
however,
that
revising
water
quality
standards,
especially
where
such
revision
is
to
deal
with
a
single
permitting
decision,
may
be
so
resource
intensive
that
it
is
not
a
realistic
option.
As
discussed
above,
if
numeric
water
quality
criteria
exist
and
are
applicable
to
a
water
body,
permits
for
dischargers
to
the
water
body
must
ensure
that
those
criteria
are
met
under
section
301(
b)(
1)(
C)
and
the
implementing
regulations
at
40
CFR
122.44(
d).
On
occasion,
States,
Tribes
and
dischargers
have
asserted
that
biological
and
toxicity
data
from
specific
waters
conflict
with
chemical
data.
EPA's
current
thinking
is
that
instances
of
clear
disagreement
between
biological
and
toxicity
data
and
chemical
data
are
infrequent.
Based
on
this
belief,
EPA
would
not
support
a
radical
shift
away
from
chemical
criteria
and
limits
or
toxicity
criteria
and
limits.
Those
tools
are
simply
too
important
as
proven
tools
for
assessing
potential
impacts
to
surface
waters
and
improving
water
quality.
EPA's
current
thinking
also
suggests
that
it
is
important
for
there
to
be
flexibility
to
resolve
instances
of
disagreement
between
different
forms
of
data
and
that
perhaps
mechanisms
for
such
flexibility
can
be
clarified
or
improved.
EPA's
current
thinking
is
that
through
collection
of
broader
and
more
thorough
water
quality
data,
EPA,
States
and
Tribes
will
be
able
to
develop
more
complete
profiles
of
water
body
conditions
and
stressors
and
that
through
such
evaluation
the
``
necessary
actions''
(
e.
g.,
water
quality­
based
effluent
limits
for
one
or
more
pollutants,
listing
of
the
water
body
as
not
attaining
its
aquatic
life
designated
use,
or
best
management
practices
to
address
nonpoint
sources
of
pollution)
to
improve
water
quality
in
a
given
water
will
become
more
obvious.
Disagreement
between
biological,
toxicity
and
chemical
data
for
the
same
water
is
cited
by
some
States
and
dischargers
as
a
potential
situation
in
which
independent
application
would
force
unnecessary
and
burdensome
requirements
on
dischargers.
Those
opposed
to
independent
application
of
criteria
would
like
to
see
States
and
Tribes
given
greater
latitude
to
determine
when
limits
based
on
a
given
criterion
are
necessary.
They
suggest
that
this
could
be
achieved
if
States
and
Tribes
were
to
include,
in
the
chemicalspecific
criteria
or
toxicity
criteria
portions
of
their
water
quality
standards,
statements
explaining
circumstances
under
which
the
otherwise
applicable
criteria
would
not
apply
at
a
particular
site
or
would
have
to
undergo
some
review
and
revision,
while
assuring
the
designated
use
of
the
water
body
would
be
maintained.
Such
circumstances
could
include
where
the
form
of
the
pollutant
in
the
effluent
or
receiving
water
is
not
the
form
addressed
by
the
chemical
criterion
in
the
State
or
Tribe's
standards;
or,
where
a
substantial
amount
of
biological
and
or
toxicity
data
indicate
that
discharges
of
the
pollutant
at
levels
that
would
exceed
the
chemical
criteria
are
not
causing
the
aquatic
life
use
in
a
particular
water
body
or
segment
of
the
water
to
be
impaired.
If
these
conditions
could
be
met,
permitting
authorities
would
have
the
flexibility
to
determine
that
a
numeric
water
quality­
based
effluent
limit
for
the
pollutant
in
question
is
not
required,
or
that
an
alternate
limit
should
apply.
This
type
of
flexibility,
to
rely
on
biological
evaluations
in
the
criteria
setting
phase,
where
data
are
sufficient
to
support
such
flexibility,
could
be
a
strong
incentive
for
States
and
Tribes
to
develop
stronger
biological
criteria
and
assessment
programs
including
monitoring
reference
areas
and
complete
chemical
and
toxicity
monitoring
programs,
including
sitespecific
data
on
most
sensitive
species
to
chemical(
s)
for
which
flexibility
is
being
sought.
EPA
approval
of
water
quality
standards
implementing
such
an
option
requires
acceptance
of
an
interpretation
that
sections
301(
b)(
1)(
C)
and
303(
c)(
2)(
B)
of
the
CWA
allow
States
and
Tribes
to
identify,
within
their
water
quality
standards,
conditions
or
circumstances
which
would
render
specific
numeric
criteria
not
applicable
to
certain
waters
in
specific
instances,
or
alternatively
in
need
of
refinement.
EPA
has
significant
technical
questions
about
how
such
an
option
could
be
implemented
within
the
context
of
a
State's
or
Tribe's
water
quality
standards.
EPA
is
especially
interested
in
detailed
technical
comments
describing
how
such
an
option
would
be
included
in
a
State's
or
Tribe's
water
quality
standards,
how
such
an
option
would
ensure
protection
of
designated
uses
in
water
bodies
where
criteria
are
deemed
not
applicable.
In
addition,
EPA
is
soliciting
comment
on
specific
procedures
that
could
be
used
by
a
State
or
Tribe
to
arrive
at
a
decision
that
a
criterion
is
not
applicable
at
a
specific
site.
In
particular,
EPA
is
interested
in
technical
evaluations
of
what
types
of
data
would
be
necessary
to
support
such
a
decision,
the
quantity
and
quality
of
the
data
and
how
the
data
would
be
evaluated.
Finally,
EPA
seeks
detailed
technical
comments
indicating
how
other
elements
of
the
water
quality
standards
program
would
function
in
situations
where
chemical
or
toxicological
water
quality
criteria
were
adjusted
based
on
biological
assessments.
For
example,
if
a
State
or
Tribe
were
to
employ
the
option
discussed
above,
it
is
not
apparent
how
critical
water
quality
program
elements
such
as
determining
the
need
for
permit
limits
or
whether
or
not
a
new
discharge
could
be
allowed
to
a
stream
segment
could
occur
absent
chemical­
specific
or
toxicity­
based
criteria
applicable
to
the
water
body.
To
be
workable,
this
option
may
need
to
be
paired
with
a
scientifically
defensible
mechanism
for
making
decisions
about
activities
such
as
permit
limits
and
load
increases.
Since
chemical
criteria
and
chemical­
specific
interpretations
of
narrative
criteria
currently
are
the
principal
benchmark
used
for
these
functions,
would
pursuing
the
option
discussed
above
be
workable,
or
would
it
introduce
a
level
of
complexity
into
State
and
Tribal
water
quality
standards
that
could
result
in
slowed
or
suspended
water
pollution
control
programs,
and
expose
aquatic
ecosystems
to
greater
risk
because
of
the
lack
of
an
identified
threshold
of
impact?
EPA's
current
thinking
is
that
significant
flexibility
already
exists
within
the
current
regulatory
framework
to
account
for
available
biological
and
toxicity
data.
For
example,
numeric
criteria,
once
adopted,
may
be
modified
to
better
reflect
conditions
at
a
specific
site.
Bioassessment
and
toxicity
data
can
play
a
valuable
role
in
identifying
sites
where
conditions
differ
sufficiently
from
those
assumed
in
the
calculation
of
the
national
or
State
or
Tribe­
wide
criteria
to
warrant
site­
specific
modification
of
the
criteria.
Bioassessment
and
toxicity
data
can
also
provide
useful
information
in
identifying
instances
where
a
given
constituent
in
an
effluent
is
toxicologically
distinct
from
a
similar
substance
for
which
a
criterion
is
available,
indicating
the
need
for
a
separate
criterion
for
the
constituent
in
36803
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
question.
Establishing
site­
specific
criteria
would
provide
relief
similar
to
that
contemplated
in
the
option
proposed
above.
Lastly,
public
participation
is
a
basic
tenet
of
the
water
quality
standards
development
process.
Public
participation
is
also
sought
in
the
context
of
issuing
NPDES
permits.
During
standards
development,
public
input
is
sought
to
assist
the
regulatory
agency
in
identifying
the
appropriate
water
quality
goals
for
the
waters
under
the
jurisdiction
of
a
State
or
Tribe.
During
NPDES
permit
issuance,
public
input
is
again
sought
to
verify
that
the
permit
proposed
to
be
issued
is
consistent
with
the
water
quality
goals.
Some
assert
that
these
two
public
participation
steps
seek
input
on
different
questions
and
are
not
interchangeable.
Does
the
weight­
ofevidence
option
discussed
above
reduce
the
opportunity
for
meaningful
public
participation
in
the
standards
setting
process
by
making
it
more
difficult
for
the
public
to
determine
which
water
quality
criteria
will
apply
to
which
water
bodies,
and,
as
a
result,
what
the
water
quality
goals
for
an
individual
water
body
are?
EPA
is
considering
how
a
weight­
of­
evidence
approach
might
be
implemented
in
a
manner
that
does
not
restrict
the
opportunities
for
meaningful
public
participation
in
the
water
quality
goal
setting
process.

Request
for
Comments
on
Independent
Application
EPA
requests
comment
on
the
following
questions:
1.
What
is
the
rationale
for
modifying
the
independent
application
policy
as
it
pertains
to
NPDES
permitting?
Under
what
circumstances
could
it
be
justified?
2.
If
there
are
circumstances
where
an
approach
other
than
independent
application
is
acceptable,
should
any
one
type
of
water
quality
data
receive
greater
weight
and
why?
3.
How
should
States
and
Tribes
evaluate
effluent
data
generated
using
chemical,
toxicity
and
biological
methods
in
determining
reasonable
potential
to
cause
or
contribute
to
an
impairment?
4.
Would
checks
or
oversight
mechanisms
be
necessary
to
ensure
that
where
decisions
about
reasonable
potential
are
based
on
chemical,
toxicity
and
biological
methods,
such
decisions
are
made
with
integrity?
For
example,
EPA
or
public
oversight?
5.
Are
there
any
cases
which
indicate
that
either
chemical­
specific,
whole
effluent
toxicity
or
biological
approaches
do
not
legitimately
represent
some
aspect
of
use
attainment?
6.
Should
EPA
explicitly
incorporate
into
the
water
quality
standards
regulation
the
independent
application
policy?
7.
Should
independent
application
be
addressed
the
same
or
differently
for
permitting
than
for
assessment
and
use
attainment
decisions
under
305(
b)
reporting
and
303(
d)
listing?
8.
If
EPA
were
to
separate
the
use
of
independent
application
in
determining
the
use
attainment
status
of
a
water
body
from
the
use
of
independent
application
when
determining
reasonable
potential
for
an
effluent,
what
approach,
independent
application,
weight­
of­
evidence,
or
hierarchical,
should
be
used
for
use
attainment
decisions?
NPDES
permitting?
What
would
the
implications
be
if
the
programs
used
two
different
policies?
9.
Would
a
policy
allowing
numeric
criteria
to
not
apply
to
all
waters
where
supported
by
scientifically
defensible
data
be
workable?
Would
it
unnecessarily
complicate
the
regulatory
program,
for
example
by
delaying
the
issuance
of
permits?
Are
existing
mechanisms
of
criteria
setting
and
permit
issuance
sufficiently
flexible?

IV.
Summary
and
Potential
Program
and
Regulation
Changes
EPA
believes
that
the
water
quality
standards
program
and
decisions
it
yields
will
continue
to
be
the
focus
of
growing
pressure
and
scrutiny
as
solutions
to
remaining
surface
water
quality
problems
in
this
country
are
found
to
be
increasingly
elusive,
difficult,
and/
or
expensive.
The
task
set
forth
by
the
Clean
Water
Act
is
to
improve
water
quality
even
where
it
is
difficult
to
do
so.
To
accomplish
this
task,
EPA
envisions
a
national
water
quality
standards
program
in
which:
the
best
possible
information
on
whether
designated
uses
are
being
attained
and
how
to
attain
and
maintain
them
is
available
and
used;
water
quality
criteria
are
selected
from
a
wide­
ranging
menu
of
scientifically
sound
criteria
and
tailored
to
each
watershed;
and
national
norms
of
consistency
and
flexibility
in
State
and
Tribal
water
quality
standards
are
clear.
With
this
vision
in
mind,
EPA,
through
this
ANPRM,
begins
a
review
of
the
water
quality
standards
regulation
in
a
public
forum
in
an
attempt
to
identify
possible
amendments
to
the
regulation
and
new
guidance
or
policy
that
may
be
needed
to
address
three
distinct
objectives:
(
1)
eliminate
any
barriers
to,
and
otherwise
enhance
State
and
Tribal
implementation
of,
watershed­
based
water
quality
planning
and
management;
(
2)
facilitate
use
of
new,
more
integrated
water
quality
assessment
and
criteria
science
in
water
quality
standards
programs,
and;
(
3)
improve
the
regulation
so
that
it
can
be
implemented
more
efficiently
and
effectively
(
including
cost­
effectively).
The
preceding
pages
of
this
ANPRM
outline
current
regulatory
provisions,
accompanying
guidance
and
policy,
and
current
practices
in
the
core
areas
of
the
water
quality
standards
program.
Each
section
of
the
ANPRM
identifies
issues
that
have
been
raised
to
EPA
that
come
out
of
the
collective
experiences
of
States,
Tribes,
cities,
industry
and
environmental
advocates,
as
well
as
EPA's
experience.
The
issue
discussions
are
followed
by
specific
questions
that
are
intended
to
elicit
focused
comments.
It
is
important
for
commenters
to
focus
on
these
specific
questions
as
a
vehicle
for
developing
comments.
It
is
equally
important
for
commenters
to
develop
ideas
that
address
the
three
objectives
above
in
a
more
general
sense
and
to
identify
the
five
to
seven
highest
priority
issues
the
commenter
believes
EPA
should
address
in
a
follow­
on
regulatory
proposal.
EPA
welcomes
ideas
on
how
the
water
quality
standards
regulation,
policy
and
or
guidance
can
be
revised
to
facilitate
water
quality
management
on
a
watershed
basis.
In
requesting
comment
on
eliminating
barriers
to
and
facilitating
implementation
of
watershed­
based
water
quality
planning
and
management,
EPA
directs
commenters'
attention
primarily
to
the
sections
on
designated
uses,
criteria,
antidegradation,
mixing
zones
and
independent
application.
In
requesting
comment
on
how
to
facilitate
use
of
new,
more
integrated
water
quality
assessment
and
criteria
science
in
water
quality
standards,
EPA
directs
commenters'
attention
primarily
to
the
sections
on
biological
criteria,
and
independent
application.
In
requesting
comment
on
how
to
improve
the
efficiency
and
effectiveness
(
including
cost­
effectiveness)
of
the
water
quality
standards
program,
all
sections
of
the
ANPRM
are
relevant
for
review.
EPA
seeks
a
water
quality
standards
program
that
protects
the
nation's
waters
as
envisioned
in
the
CWA,
that
establishes
requirements
that
are
necessary
to
attain
and
maintain
healthy
and
sustainable
ecosystems,
and
that
is
flexible
enough
for
States
and
Tribes
to
protect
water
quality
and
at
the
same
time
avoid
costly
requirements
that
have
little
or
no
environmental
benefit.
Below
is
a
brief
summary
outline
of
the
potential
changes
to
the
water
quality
standards
program
and
36804
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
regulation
that
are
discussed
and
considered
in
this
ANPRM.
The
list
of
potential
changes
includes
the
potential
changes
to
the
program
and
regulation
on
which
EPA
is
specifically
requesting
comment.
Each
area
of
potential
change
is
discussed
in
detail
in
the
specified
section
of
the
ANPRM.
It
is
possible
that
EPA
will
ultimately
propose
some
of
the
changes
outlined
below.
It
is
also
possible
that
EPA
will
conclude
based
on
the
public
comments
it
receives
that
some
or
all
of
the
issues
presented
in
the
ANPRM
can
be
best
addressed
through
non­
regulatory
mechanisms
such
as
guidance
or
policy.

A.
Uses
1.
Refinement
of
use
designations
to
achieve
increased
specificity
in
aquatic
life
and
recreation
uses
being
protected.
2.
Minimum
elements
of
a
use
attainability
analysis
(
UAA).
3.
When
is
UAA
required/
not
required?
a.
UAAs
whenever
an
aquatic
life
use
is
designated
(
beyond
fishable/
swimmable)
to
see
if
the
use
reflects
the
highest
potential
for
the
water
body.
b.
Periodic
review
of
marginal
or
limited
aquatic
life
use
designations.
c.
When
is
a
use
considered
attainable?
d.
Conditions
under
which
refinements
in
designated
uses
may
be
considered
actions
not
requiring
analysis
to
support
use
removal
and
alternatively
the
conditions
under
which
such
action
is
considered
a
use
removal
requiring
justification
under
§
131.10(
g).
e.
Circumstances
under
which
UAA
is
required
and
circumstances
under
which
UAA
must
be
reviewed.
4.
Removal
of
designated
uses.
a.
Minimum
aquatic
life
uses
for
all
waters,
because
even
degraded
water
bodies
support
some
form
of
aquatic
life.
b.
Evaluate
use
removal
provision
at
§
131.1(
10)(
g)
allowing
removal
of
a
use
due
to
the
existence/
operation
of
a
dam.
c.
Clarify
whether
the
physical
factors
reason
for
removing
a
use
includes
removal
of
a
recreational
use
due
to
poor
physical
access
to
the
water.
Alternatively,
the
removal
of
a
use
for
physical
factors
could
be
limited
to
aquatic
life
uses
only.
d.
Clarify
in
§
131.10
that
at
least
one
of
the
six
use
removal
criteria
must
be
met
to
remove
any
use,
not
just
aquatic
life
and
recreation
uses.
5.
Alternatives
to
use
downgrade
such
as
variances,
temporary
standards
and
ambient­
based
criteria.
a.
Recognize
site­
specific
criteria
set
to
natural
background
levels
as
a
permissible
alternative
to
use
downgrade.
b.
Recognize
site­
specific
criteria
set
to
irreversible
anthropogenic
background
levels
as
a
permissible
alternative
to
use
downgrade.

B.
Criteria
1.
Ambient
Water
Quality
criteria
for
Aquatic
Life
Protection.
a.
Examination
and
possible
interim
revisions
to
EPA
recommendations
on
the
duration
and
frequency
of
criteria
excursions
to
account
for
organism
response
model
and
population
response
model.
2.
Site­
specific
criteria
and
procedures.
a.
Specify
that
States
and
Tribes
must
have
regulatory
procedures
for
establishing
site­
specific
criteria.
b.
Minimum
requirements
for
development
of
site­
specific
criteria.
3.
Narrative
criteria
and
interpretation
procedures.
a.
Identify
additional
methods
for
implementation
of
narrative
criteria.
b.
Clarify
that
States
and
Tribes
are
required
to
adopt
narrative
criteria
for
all
waters.
(
all
States
already
have).
4.
Codification
of
CWA
requirement
to
adopt
numeric
toxics
criteria.
a.
Define
``
reasonable
expectation''
under
303(
c)(
2)(
B).
(``
States
and
Tribes
may
adopt
numeric
chemical­
specific
criteria
for
those
stream
segments
where
the
State
or
Tribe
determines
that
the
priority
toxic
pollutants
for
which
EPA
has
issued
CWA
section
304(
a)
criteria
guidance
are
present
and
can
reasonably
be
expected
to
interfere
with
designated
uses.''
emphasis
added)
5.
Chemical
criteria
beyond
priority
pollutants.
a.
Develop
and
recommend
or
require
criteria
for
certain
non­
priority
pollutants.
6.
Numeric
values
in
the
absence
of
criteria
or
data
sufficient
for
criteria.
a.
States
and
Tribes
develop
method
for
derivation
of
alternative
values
where
minimum
data
requirements
for
criteria
not
satisfied.
Specific
EPA
derivation
procedure
or
guidelines.
7.
Require
or
recommend
that
State
and
Tribes
adopt
numeric
toxicity
criteria.
8.
Sediment
quality
criteria.
a.
Require
or
recommend
that
States
and
Tribes
adopt
sediment
criteria
(
narrative
or
numeric).
b.
Specify
in
regulation
that
States
and
Tribes
have
the
flexibility
to
adopt
sediment
quality
criteria.
9.
Biological
criteria.
a.
Require
or
recommend
that
States
and
Tribes
adopt
biological
criteria
(
narrative
or
numeric).
b.
Specify
in
regulation
that
States
and
Tribes
have
the
flexibility
to
adopt
biological
criteria.
c.
Specify
linkage
between
biological
criteria
and
stressor
identification.
10.
Wildlife
Criteria.
a.
Recognize
in
regulatory
text
that
wildlife
criteria
are
valid
forms
of
water
quality
criteria.
b.
Recognize
in
regulatory
text
that
wildlife
criteria
endpoints
other
than
bioaccumulation
endpoints
are
valid
bases
for
wildlife
criteria.
11.
Physical
criteria:
Existing
and
potential
future
role
of.
a.
Identify
physical
criteria
such
as
habitat
(
including
clean
sediment)
and
hydrologic
balance
criteria
in
40
CFR
131
as
valid
forms
of
criteria
that
States
and
Tribes
can
adopt
in
their
water
quality
standards.
12.
Human
Health
Criteria.
a.
Higher
fish
consumption
assumptions
for
site­
specific
or
regional
situations
when
subpopulations
that
are
highly
exposed
have
been
identified.
b.
Clarification
of
the
use
of
MCLs
and
MCLGs
in
State
and
Tribal
water
quality
standards.

C.
Antidegradation
1.
Minimum
elements
of
State
and
Tribal
antidegradation
implementation
procedures.
a.
Revise
regulation
to
include
the
minimum
elements
of
a
State
and
Tribal
antidegradation
implementation
method.
b.
Revise
the
regulation
to
explicitly
say
that
State
and
Tribal
antidegradation
implementation
procedures
(
in
addition
to
just
the
policy)
must
be
submitted
in
triennial
review
package
and
are
reviewable
by
EPA.
2.
Tier
1
protection
(
protection
of
existing
uses).
a.
Define
or
clarify
what
constitutes
loss
of
an
existing
in­
stream
water
use.
b.
Specify
that
a
clear
approach
to
maintaining
and
protecting
existing
uses
that
may
not
be
adequately
protected
by
strict
application
of
water
quality
criteria
is
a
required
element
of
an
antidegradation
implementation
procedure.
3.
Waters
covered
by
tier
2
level
protection.
a.
Clarify
waters
subject
to
tier
2
level
protection.
b.
Clarify
tier
2
provision
requiring
all
cost
effective
and
reasonable
best
management
practices
for
nonpoint
sources
prior
to
allowing
a
lowering
of
water
quality.
c.
Clarify
that
States
and
Tribes
are
to
consider
the
303(
d)
listing
status
of
a
water
body,
and
the
information
supporting
that
status,
when
determining
whether
a
proposed
activity
that
is
expected
to
degrade
water
quality
in
that
water
body
can
be
authorized
under
tier
2
of
the
State's
or
Tribe's
antidegradation
provisions.
36805
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
4.
Outstanding
national
resource
water
(
ONRW)
classification,
level
of
protection,
and
public
role
in
nominating.
a.
Public
nomination
of
ONRWs.
b.
Level
of
protection
afforded
to
ONRWs.
5.
Creation
of
Antidegradation
tier
2.5.
a.
Revise
the
regulation
to
explicitly
recognize
tier
2.5
protection.

D.
Mixing
Zone
Policy
and
Implementation
Procedures
1.
Specify
that,
to
use
mixing
zones,
States
and
Tribes
must
indicate
in
their
water
quality
standards
whether
they
allow
mixing
zones,
conditions
under
which
mixing
zones
are
allowed,
minimum
requirements
for
mixing
zones.
2.
Procedures
and
decision
criteria
used
in
addressing
complete
and
incomplete
mixing.
3.
Site­
specific
technical
justification
for
rapid
and
complete
mix
assumption.
4.
State
and
Tribe
policies
and
procedures
to
address
rate
of
mixing.
5.
Clarify
in
regulation
that
narrative
criteria
apply
in
mixing
zones.
6.
Restrict
Mixing
zones
for
bioaccumulative
chemicals
of
concern.

E.
Applicability
of
Water
Quality
Standards
to
Wetlands
1.
Clarify
in
40
CFR
Part
131
that
wetlands
with
interstate
commerce
connection
are
waters
of
the
U.
S.
requiring
water
quality
standards.

F.
Evaluation
of
EPA
Policy
of
Independent
Application
(
IA)

1.
Increase
use
of
chemical,
toxicological,
physical
and
biological
data
in
making
water
body
assessments
in
a
consistent
and
scientifically
defensible
manner.
2.
Specify
how,
and
the
circumstances
under
which,
different
forms
of
assessments
(
chemical,
toxicological,
physical
and
biological)
can
be
used
together
to
determine:
a.
When
a
designated
aquatic
life
use
is
or
is
not
attained,
b.
The
type
and
value
of
criteria
that
should
apply
to
a
water,
and
c.
When
water
quality­
based
effluent
limits
are
required
in
a
permit.
3.
Specify
the
adequate
data
base
and
level
of
rigor
necessary
in
biological
assessments
to
support
a
determination
of
full
use
support
despite
differences
in
assessment
results.
In
addition
to
the
potential
program
and
regulation
changes
outlined
above,
EPA
is
also
requesting
comment
on
the
costs
and
benefits
and
potential
reporting
and
record
keeping
requirements
that
might
be
associated
with
these
changes.
These
issues
are
discussed
more
fully
in
the
next
section.

V.
Regulatory
Assessment
Requirements
A.
Executive
Order
(
E.
O.)
12866,
Regulatory
Planning
and
Review
Under
Executive
Order
12866,
[
58
Federal
Register
51,735
(
October
4,
1993)]
the
Agency
must
determine
whether
the
regulatory
action
is
``
significant''
and
therefore
subject
to
Office
of
Management
and
Budget
(
OMB)
review
and
the
requirements
of
the
Executive
Order.
The
Order
defines
``
significant
regulatory
action''
as
one
that
is
likely
to
result
in
a
rule
that
may:
(
1)
Have
an
annual
effect
on
the
economy
of
$
100
million
or
more
or
adversely
affect
in
a
material
way
the
economy,
a
sector
of
the
economy,
productivity,
competition,
jobs,
the
environment,
public
health
or
safety,
or
State,
local,
or
tribal
governments
or
communities;
(
2)
Create
a
serious
inconsistency
or
otherwise
interfere
with
an
action
taken
or
planned
by
another
agency;
(
3)
Materially
alter
the
budgetary
impact
of
entitlements,
grants,
user
fees,
or
loan
programs
or
the
rights
and
obligations
of
recipients
thereof;
or
(
4)
Raise
novel
legal
or
policy
issues
arising
out
of
legal
mandates,
the
President's
priorities,
or
the
principles
set
forth
in
the
Executive
Order.
While
this
advance
notice
of
proposed
rule
making
establishes
no
regulatory
requirements
it
could
ultimately
result
in
a
rule
that
would
satisfy
one
or
more
of
the
above
criteria.
It
has
therefore
been
determined
that
this
action
is
a
``
significant
regulatory
action''
under
the
terms
of
Executive
Order
(
E.
O.)
12866.
As
such
this
action
was
submitted
to
OMB
for
review.
Changes
made
in
response
to
OMB
suggestions
or
recommendations
have
been
documented
in
the
public
record.
Under
the
terms
of
E.
O.
12866,
EPA
is
to
prepare
for
any
significant
regulatory
action
an
assessment
of
its
potential
costs
and
benefits.
If
that
action
satisfies
the
first
of
the
criteria
listed
above,
this
assessment
must
include,
to
the
extent
feasible,
a
quantification
of
these
costs
and
benefits,
the
underlying
analyses
supporting
such
quantification,
and
an
assessment
of
the
costs
and
benefits
of
reasonably
feasible
alternatives
to
the
planned
regulation.
Because
the
purpose
of
this
notice
is
to
initiate
a
structured
national
debate
on
a
broad
set
of
issues
rather
than
to
propose
specific
regulatory
changes,
it
is
not
feasible
to
quantify
the
costs
and
benefits
of
any
resulting
regulations
at
this
time.
The
Agency
is
aware,
however,
that
this
notice
could
lead
to
a
regulatory
action
for
which
the
preparation
of
a
quantitative
assessment
of
costs
and
benefits
would
be
appropriate.
The
Agency
is
thus
requesting
comment
on
the
costs
and
benefits
of
any
of
the
possible
regulatory
changes
discussed
in
this
notice,
as
well
as
on
appropriate
methodologies
for
assessing
them.
The
Agency
would
be
particularly
interested
to
hear
from
States
and
Tribes
that
may
already
have
experience
implementing
some
of
the
measures
discussed
in
this
Notice
and
may
already
have
prepared
analyses
of
the
costs
and/
or
benefits
of
such
measures.
Other
members
of
the
public
are
also
encouraged
to
submit
any
data
they
may
have
on
the
costs
and
benefits
of
specific
measures
(
e.
g.,
conducting
biological
assessments).

B.
The
Regulatory
Flexibility
Act
(
RFA)
as
Amended
by
the
Small
Business
Regulatory
Enforcement
Fairness
Act
(
SBREFA)
of
1996
Under
the
RFA,
(
5
U.
S.
C.
601
et
seq.),
as
amended
by
SBREFA,
for
proposed
rules,
EPA
generally
is
required
to
conduct
an
initial
regulatory
flexibility
analysis
(
IRFA)
describing
the
impact
of
the
regulatory
action
on
small
entities
as
part
of
rulemaking.
However,
under
section
605(
b)
of
the
RFA,
if
the
Administrator
for
the
Agency
certifies
that
the
rule
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities,
EPA
is
not
required
to
prepare
an
IRFA.
The
requirement
applies
to
proposed
rules
only
and
as
this
notice
is
an
ANPRM,
these
requirements
do
not
apply
to
this
notice.

C.
Paperwork
Reduction
Act
Under
the
implementing
regulations
for
the
Paperwork
Reduction
Act,
an
agency
is
required
to
certify
that
any
agency­
sponsored
collection
of
information
from
the
public
is
necessary
for
the
proper
performance
of
its
functions,
has
practical
utility,
is
not
unnecessarily
duplicative
of
information
otherwise
reasonably
accessible
to
the
agency,
and
reduces
to
the
extent
practicable
and
appropriate
the
burden
on
those
required
to
provide
the
information
(
5
CFR
1320.9).
Any
proposed
collection
of
information
must
be
submitted,
along
with
this
certification,
to
the
Office
of
Management
and
Budget
for
approval
before
it
goes
into
effect.
Most
of
the
potential
regulatory
changes
discussed
in
this
Notice
could
entail
new
reporting
and
record
keeping
requirements
for
States
and
Tribes
and/
or
members
of
the
regulated
public.
EPA
36806
Federal
Register
/
Vol.
63,
No.
129
/
Tuesday,
July
7,
1998
/
Proposed
Rules
is
interested
in
comments
on
any
and
all
aspects
of
these
potential
paperwork
requirements,
and
in
particular
on
how
they
should
be
structured
to
fulfill
the
requirements
that
they
have
practical
utility,
are
not
unnecessarily
duplicative
of
other
available
information,
and
are
the
least
burdensome
necessary
to
satisfy
the
purposes
of
the
Water
Quality
Standards
Program.

Dated:
June
25,
1998.
Robert
Perciasepe,
Assistant
Administrator
for
Water.
[
FR
Doc.
98
 
17513
Filed
7
 
6
 
98;
8:
45
am]

BILLING
CODE
6560
 
50
 
P
