D­
1
GLOSSARY
Action
level
(
for
chlorophyll
a):
According
to
OAR
340­
41­
150,
an
average
chlorophyll
a
level
of
15
ug/
L
is
set
to
identify
rivers
where
algae
may
impair
the
beneficial
uses.
This
value
is
not
a
numeric
criteria,
rather
it
triggers
a
requirement
for
DEQ
to
conduct
studies.
When
this
action
level
is
exceeded,
DEQ
will
conduct
studies
to
determine
the
probable
causes
of
the
exceedance
and
develop
a
control
strategy
for
attaining
compliance
with
the
action
level.

Best
Management
Practice
(
BMP):
A
physical,
structural,
non­
structural,
or
managerial
practice,
when
used
singly
or
in
combination,
prevents,
reduces,
or
minimizes
water
pollution
and/
or
water
quantity.

Biochemical
Oxygen
Demand
(
BOD):
The
amount
of
oxygen
per
unit
volume
of
water
required
to
bacterially
or
chemically
oxidize
(
stabilize)
the
oxidizable
matter
in
water.
Biochemical
oxygen
demand
measurements
are
usually
conducted
over
specified
time
intervals
(
5,
10
,20
,30
days).
The
term
BOD
generally
refers
to
the
standard
5
day
BOD
test.

Combined
Sewer
Overflow
(
CSO):
Discharges
from
sewer
systems
that
are
designed
to
carry
storm
water
rainfall
and
snowmelt
runoff,
along
with
sanitary
sewage,
pretreated
industrial
wastewater,
and
a
certain
quantity
of
flow
from
storm
and
groundwater
infiltration.

Designated
Management
Agency:
The
agency
required
to
develop
a
Water
Quality
Management
Plan
(
WQMP)
under
a
Total
Maximum
Daily
Load
(
TMDL)
and
having
authority
to
implement
the
specified
control
recommendations.

Epiphyte:
a
plant
growing
on
another
plant.

Eutrophication:
Enrichment
of
an
aquatic
ecosystem
with
nutrients
(
nitrates,
phosphates)
that
accelerate
biological
productivity
(
growth
of
algae
and
weeds)
and
an
undesirable
accumulation
of
algal
biomass.

Illicit
Discharge:
any
discharge
to
a
municipal
separate
storm
sewer
system
that
is
not
composed
entirely
of
storm
water
(
except
discharges
covered
under
an
NPDES
permit).

Loading
Capacity
(
LC):
The
greatest
amount
of
loading
that
a
water
can
receive
without
violating
water
quality
standards.

Load
Allocation
(
LA):
The
portion
of
a
receiving
water's
loading
capacity
that
is
attributed
to
either
to
one
of
its
existing
or
future
nonpoint
sources
of
pollution
or
to
natural
background
sources.
Wherever
possible,
natural
and
nonpoint
source
loads
should
be
distinguished.
D­
2
Macrophyte:
A
large,
vascular,
rooted
aquatic
plant.

Margin
of
Safety
(
MOS):
A
required
component
of
the
TMDL
that
accounts
for
the
uncertainty
about
the
relationship
between
the
pollutant
loads
and
the
quality
of
the
receiving
waterbody.
The
MOS
can
be
incorporated
into
conservative
assumptions
used
to
develop
TMDLs,
generally
within
the
calculations
or
models.
An
additional
MOS
can
be
added
as
a
separate
component
of
the
TMDL.
Quantitatively
this
is
expressed
as:
TMDL
=
LC
=

WLA
+

LA
+
MOS
Memorandum
of
Agreement:
A
mutual
agreement
between
Oregon
Department
of
Environmental
Quality
(
DEQ)
and
the
Designated
Management
Agencies
(
DMAs)
for
implementation
of
the
Water
Quality
Management
Plan
(
WQMP).

National
Pollutant
Discharge
Elimination
System
(
NPDES)
Permit:
A
license
to
discharge
pollutants,
as
prescribed
by
the
Clean
Water
Act.

Storm
water:
storm
water
runoff,
snow
melt
runoff
and
surface
runoff
and
drainage
Total
Maximum
Daily
Load
(
TMDL):
The
sum
of
the
individual
WLAs
for
point
sources
and
LAs
for
nonpoint
sources
and
natural
background.

Wasteload
Allocation
(
WLA):
The
portion
of
a
receiving
water's
loading
capacity
that
is
allocated
to
one
of
its
existing
or
future
point
sources
of
pollution.

Water
Quality
Criteria:
Water
quality
criteria
consist
of
numeric
and
narrative
criteria.
Numeric
criteria
are
scientifically
derived
ambient
concentrations
developed
by
EPA
or
States
for
various
pollutants
of
concern
to
protect
human
health
and
aquatic
life.
Narrative
criteria
are
statements
that
describe
the
desired
water
quality
goal.

Water
Quality
Limited
Segments:
Those
water
segments
that
do
not
or
are
not
expected
to
meet
applicable
water
quality
standards
even
after
the
application
of
technology
based
effluent
limitations.

Water
Quality
Management
Plan:
A
watershed
enhancement
approach
which
includes
goals
and
objectives
that
focus
on
achieving
water
quality
standards
at
the
earliest
possible
date.

Water
Quality
Standards
(
WQS):
A
law
or
regulation
that
consists
of
the
beneficial
use
or
uses
of
a
waterbody,
the
numeric
and
narrative
water
quality
criteria
that
are
necessary
to
protect
the
use
or
uses
of
that
particular
waterbody,
and
an
antidegradation
statement.
