1
31
January
2003
Regional
Methodology
Used
in
the
§
316(
b)
Phase
II
Notice
of
Data
Availability
Objectives
of
Regional
Approach
In
its
analysis
for
the
§
316(
b)
Phase
II
proposal,
EPA
relied
on
nine
case
studies
to
estimate
the
potential
economic
benefits
of
reduced
impingement
and
entrainment
(
I&
E)
EPA
extrapolated
facility­
specific
estimates
to
other
facilities
located
on
the
same
waterbody
type
and
summed
the
results
for
all
waterbody
types
to
obtain
national
estimates.
A
number
of
commenters
expressed
concern
about
this
method
of
extrapolation,
noting
that
even
within
the
same
water
body
type,
there
are
important
ecological
and
socioeconomic
differences
among
different
regions
of
the
country.
For
example,
commercial
and
recreational
fisheries
of
Atlantic
Coast
estuaries
are
substantially
different
from
those
of
Pacific
Coast
estuaries.

To
address
this
concern,
EPA
has
revised
the
design
of
its
analysis
to
examine
impingement
and
entrainment
(
I&
E)
losses,
and
the
economic
benefits
of
reducing
these
losses,

at
the
regional­
scale.
The
estimated
benefits
are
then
aggregated
across
all
regions
to
yield
a
national
benefit
estimate.

EPA
is
proposing
this
regional
approach
for
the
national
rulemaking
effort,
but
is
not
advocating
that
this
approach
be
followed
for
impact
and/
or
benefits
analyses
that
might
be
conducted
for
individual
National
Pollution
Discharge
Elimination
System
(
NPDES)
permits.

At
the
individual
permit
level
it
is
both
necessary
and
possible
to
conduct
a
more
detailed,

sitespecific
analysis
on
the
environmental
ramifications
of
cooling
water
intake
structures
governed
by
the
permit
in
question
than
is
necessary
or
feasible
for
this
national­
level
rulemaking
analysis.

Definitions
of
Regions
