­
1­
316b
Phase
II
Cost
Module
4.0
Fish
Barrier
Nets
Fish
barrier
net
can
be
used
where
improvements
to
impingement
performance
is
needed.
Because
barrier
nets
can
be
installed
independently
of
intake
structures,
there
is
no
need
to
include
any
costs
for
modifications
to
the
existing
intake
or
technology
employed.
Costs
are
assumed
to
be
the
same
for
both
new
and
existing
facilities.
Barrier
nets
can
be
installed
while
the
facility
is
operating.
Thus,
there
is
no
need
to
coordinate
barrier
net
installation
with
generating
unit
downtime
.

Fish
Barrier
Net
Questionnaire
EPA
identified
seven
facilities
from
its
database
that
employed
fish
barrier
nets
and
sent
them
a
brief
questionnaire
requesting
barrier
net
design
and
cost
data
(
EPA
2002).
The
following
four
facilities
received
but
did
not
submit
a
response:

Bethlehem
Steel
­
Sparrows
Point
Consumers
Energy
Co.
­
J.
R.
Whiting
Plant
Exelon
Corp.
(
formerly
Commonwealth
Edison)
­
LaSalle
County
Station
Southern
Energy
­
Bowline
Generating
Station
The
following
three
facilities
submitted
completed
questionnaires:

Entergy
Arkansas,
Inc.
­
Arkansas
Nuclear
One
Potomac
Electric
Power
Co.
­
Chalk
Point
Minnesota
Power
­
Laskin
Energy
Center
Net
Velocity
An
important
design
criterion
for
determining
the
size
of
fish
barrier
nets
is
the
velocity
of
the
water
as
it
passes
through
the
net.
Net
velocity
(
which
is
similar
to
the
approach
velocity
for
a
traveling
screen)
determines
how
quickly
debris
will
collect
on
the
nets.
Net
velocity
also
determines
the
force
exerted
on
the
net,
especially
if
it
becomes
clogged
with
debris.
For
facilities
that
supplied
technical
data,
Table
4­
1
presents
the
design
intake
flow
(
estimated
by
EPA)
and
facility
data
reported
in
the
Barrier
Net
Questionnaire.
These
data
include
net
size,
average
daily
intake
flow,
and
calculated
net
velocities
based
on
average
and
design
flows.
The
two
larger
facilities
have
similar
design
net
velocity
values
that,
based
on
design
flow,
is
equal
to
0.06
feet
per
second
(
fps).
This
value
is
roughly
an
order
of
magnitude
lower
than
compliance
velocities
used
for
rigid
screens
in
the
Phase
I
Rule
as
well
as
design
velocities
recommended
for
passive
screens.
There
are
two
reasons
for
this
difference.
One
difference
is
rigid
screens
can
withstand
greater
pressure
differentials
because
they
are
firmly
held
in
place.
The
second
is
rigid
screens
can
afford
to
collect
debris
at
a
more
rapid
rate
because
they
have
an
active
means
for
removing
debris
collected
on
the
surface.

Based
on
the
data
presented
in
Table
4­
1,
EPA
has
selected
a
net
velocity
of
0.06
fps
(
using
the
design
flow)
as
the
basis
for
developing
compliance
costs
for
fish
barrier
nets.
Nets
tested
at
a
high
velocity
(>
1.3
fps)
at
a
power
plant
in
Monroe
Michigan
clogged
and
collapsed.
Velocities
higher
­
2­
Facility
Owner
Facility
Name
Depth*
Length*
Area
EPA
Design
Flow
Net
Velocity
at
Design
Flow
Average
Daily
Flow*
Net
Velocity
at
Daily
Flow
Ft
Ft
sq
ft
gpm
fps
gpm
fps
PEPCO
Chalk
Point
30
900
27,000
762,500
0.06
500,000
0.04
Entergy
Arkansas
Nuclear
One
20
1500
30,000
805,600
0.06
593,750
0.04
Minn.
Power
Laskin
Energy
Center
16
600
9,600
101,900
0.02
94,250
0.02
than
0.06
fps
may
be
acceptable
at
locations
where
the
debris
loading
is
low
or
where
additional
measures
are
taken
to
remove
debris.
While
tidal
locations
can
have
significant
water
velocities,
the
periodic
reversal
of
flow
direction
can
help
dislodge
some
of
the
debris
that
collects
on
the
nets.
The
technology
scenario
described
below,
for
tidal
waterbodies,
is
designed
to
accommodate
significant
debris
loading
through
the
use
of
dual
nets
and
frequent
replacement
with
cleaned
nets.

Table
4­
1
Net
Velocity
Data
Derived
from
Barrier
Net
Questionnaire
Data
Mesh
Size
Mesh
size
determines
the
fish
species
and
juvenile
stages
that
will
be
excluded
by
the
net.
While
smaller
mesh
size
has
the
ability
to
exclude
more
organisms,
it
will
plug
more
quickly
with
debris.
The
Chalk
Point
facility
tried
to
use
0.5­
inch
stretch
mesh
netting
and
found
that
too
much
debris
collected
on
the
netting;
it
instead
uses
0.75
inch
stretch
(
0.375
inch
mesh)
netting
(
Langley
2002).
Unlike
rigid
screens,
fish
nets
are
much
more
susceptible
to
lateral
forces
which
can
collapse
the
net.

Mesh
size
is
specified
in
one
of
two
ways,
either
as
a
"
bar"
or
"
stretch"
dimension.
A
"
stretch"
measurement
refers
to
the
distance
between
two
opposing
knots
in
the
net
openings
when
they
are
stretched
apart.
Thus,
assuming
a
diamond
shaped
netting,
when
the
netting
is
relaxed
the
distance
between
two
opposing
sides
of
an
opening
will
be
roughly
½
the
stretch
diameter.
A
"
bar"
measurement
is
the
length
of
one
of
the
four
sides
of
the
net
opening
and
would
be
roughly
equal
to
½
the
stretch
measurement.
The
term
"
mesh
size"
as
used
in
this
document
refers
to
either
½
the
"
stretch"
measurement
or
is
equal
to
the
"
bar"
measurement
Table
4­
2
presents
reported
mesh
sizes
from
several
power
plant
facilities
that
either
now
or
in
the
past
employed
fish
barrier
nets.
An
evaluation
report
of
the
use
of
barrier
fish
nets
at
the
Bowline
Plant
in
New
York
cited
that
0.374
inch
mesh
was
more
effective
than
0.5
inch
mesh
at
reducing
the
number
of
fish
entering
the
plant
intake
(
Hutcheson
1988).
Both
fish
barrier
net
cost
scenarios
described
below
are
based
on
nets
with
a
mesh
size
of
0.375
in.
(
9.5
mm)
and
corresponds
to
the
median
mesh
size
of
those
identified
by
EPA.

Twine
Twine
size
mostly
determines
the
strength
and
weight
of
the
fish
netting.
Only
the
Chalk
Point
facility
reported
twine
size
data
(#
252)
knotless
nylon
netting.
Netting
#
252
is
a
75­
lb
test
braided
nylon
twine
in
which
the
twine
joints
are
braided
together
rather
than
knotted
(
Murelle
2002).
The
netting
used
at
the
Bowline
Power
Plant
was
cited
as
multi­
filament
knotted
nylon,
chosen
because
of
its
low
cost
and
high
strength
(
Hutcheson
1988).
­
3­
Facility
Description
Type
of
Measurement
and
Source
Inch
mm
Inch
mm
Inner
Net
0.75
19
Stretch
(
1)
0.375
9.5
Outer
Net
1.25
32
Stretch
(
1)
0.625
15.9
Low
0.375
10
Mesh
(
Bar)
(
1)
0.375
9.5
High
(
preferred)
0.5
13
Mesh
(
Bar)
(
1)
0.5
12.7
Laskin
Energy
0.25
6.4
Mesh
(
Bar)
(
1)
0.25
6.4
Bowline
Point
More
Effective
Size
0.374
9.5
Bar
(
3)
0.374
9.5
J.
P.
Pulliam
0.25
6.4
Stretch
(
2)
0.126
3.2
Median
0.374
9.5
(
1):
2002
EPA
Fish
Barrier
Survey
(
2):
ASCE
1982
(
3):
Hutcheson
1988
Reported
Mesh
Size
Entergy
Arkansas
Nuclear
One
Effective
Mesh
Size
Chalk
Point
Table
4­
2
Available
Barrier
Net
Mesh
Size
Data
Support/
Anchoring
System
In
general,
two
different
types
of
support
and
anchoring
systems
have
been
identified
by
EPA.
In
the
simplest
system
the
nets
are
held
in­
place
and
the
bottom
is
sealed
with
weights
running
the
length
of
the
bottom
usually
consisting
of
a
chain
or
a
lead
line.
The
weights
may
be
supplemented
with
anchors
placed
at
intervals.
Vendors
indicated
the
requirement
for
anchors
varies
depending
on
the
application
and
waterbody
conditions.
The
nets
are
anchored
along
the
shore
and
generally
placed
in
a
semi­
circle
or
arc
in
front
of
the
intake.
The
Bowline
Facility
net
used
a
v­
shape
configuration
with
an
anchor
and
buoy
at
the
apex
and
additional
anchors
placed
midway
along
the
91
meter
length
sides.
In
some
applications
anchors
may
not
be
needed
at
all.
If
the
nets
are
moved
by
current
or
waves,
they
can
be
set
back
into
the
proper
position
using
a
boat.
The
nets
are
supported
along
the
surface
with
buoys
and
floats.
The
buoys
may
support
signs
warning
boaters
of
the
presence
of
the
net.
The
required
spacing
and
size
of
the
anchors
and
buoys
is
somewhat
dependent
on
the
size
of
the
net
and
lateral
water
velocities.
The
majority
of
facilities
investigated
used
this
float/
anchor
method
of
installation.
This
net
support
configuration,
using
weights,
anchors,
floats,
and
buoys,
is
the
basis
for
compliance
scenario
A.

A
second
method
is
to
support
nets
between
evenly
spaced
pilings.
This
method
is
more
appropriate
for
water
bodies
with
currents.
The
Chalk
Point
Power
Plant
uses
this
method
in
a
tidal
river.
The
Chalk
Point
facility
uses
two
concentric
nets.
Each
has
a
separate
set
of
support
pilings
with
a
spacing
between
pilings
of
about
18
feet
to
20
feet
(
Langley
2002).
Nets
are
hung
on
the
outside
of
the
pilings
with
spikes
and
are
weighted
on
the
bottom
with
galvanized
chain.
During
the
winter
the
top
of
the
net
is
suspended
below
the
water
surface
to
avoid
ice
damage
but
generally
thick
ice
does
not
persist
during
the
winter
months
at
the
facility
location.
­
4­
Debris
Debris
problems
generally
come
in
two
forms.
In
one
case
large
floating
debris
can
get
caught
in
the
netting
near
the
surface
and
result
in
tearing
of
the
netting.
In
the
other
cases,
floating
and
submerged
debris
can
plug
the
openings
in
the
net.
This
increases
the
hydraulic
gradient
across
the
net,
resulting
in
net
being
pulled
in
the
downstream
direction.
The
force
can
become
so
great
that
it
can
collapse
the
net,
and
water
flows
over
the
top
and/
or
beneath
the
bottom.
If
the
net
is
held
in
place
by
only
anchors
and
weights
it
may
be
moved
out
of
place.
At
the
Chalk
Point
facility,
debris
that
catches
on
the
nets
mostly
comes
in
the
form
of
jellyfish
and
colonial
hydroids
(
Langley
2002).

Several
solutions
are
described
for
mitigating
problems
created
by
debris.
At
the
Chalk
Point
Power
Plant
two
concentric
nets
are
deployed.
The
outer
net
has
a
larger
mesh
opening
designed
to
capture
and
deflect
larger
debris
so
it
does
not
encounter
the
inner
net,
which
catches
smaller
debris.
This
configuration
reduces
the
debris
buildup
on
any
one
net
extending
the
time
period
before
net
cleaning
is
required.
Growth
of
algae
and
colonization
with
other
organisms
(
biofouling)
can
also
increase
the
drag
force
on
the
nets.
Periodic
removal
and
storage
out
of
the
water
can
solve
this
problem.
At
Chalk
Point
both
nets
are
changed
out
with
cleaned
nets
on
a
periodic
basis.
This
approach
is
considered
to
be
appropriate
for
high
debris
locations.

Another
solution
is
to
periodically
lift
the
netting
and
manually
remove
debris.
A
solution
for
floating
debris
is
to
place
a
debris
boom
in
front
of
the
net
(
Hutcheson
1988).

Ice
During
the
wintertime
ice
can
create
problems
in
that
the
net
can
become
embedded
in
surface
ice
with
the
net
subject
to
tear
forces
when
the
ice
breaks
up
or
begins
to
move.
Flowing
ice
can
create
similar
problems
as
floating
debris.
Ice
will
also
affect
the
ability
to
perform
net
maintenance
such
as
debris
removal.
Solutions
include:

°
Removing
the
nets
during
winter
°
Drop
the
upper
end
of
the
net
to
a
submerged
location;
can
only
be
used
with
fixed
support,
such
as
pilings
and
in
locations
where
thick
ice
is
uncommon
°
Installing
an
air
bubbler
below
the
surface.
Does
not
solve
problems
with
flowing
ice.

Net
Deployment
EPA
assumes
that
barrier
nets
will
be
used
to
augment
performance
of
the
existing
shore­
based
intake
technology
such
as
traveling
screens.
The
float/
anchor
supported
nets
are
assumed
to
be
deployed
on
a
seasonal
basis
to
reduce
impingement
of
fish
present
during
seasonal
migration.
The
Arkansas
Energy
Arkansas
Nuclear
One
Plant
deploys
their
net
for
about
120
days
during
winter
months.
The
Minnesota
Power
Laskin
Energy
Center,
which
is
located
on
a
lake,
deploys
the
net
when
ice
has
broken
up
in
spring
and
removes
the
net
in
the
fall
before
ice
forms.
Thus,
the
actual
deployment
period
will
vary
depending
on
presence
of
ice
and
seasonal
migration
of
fish.
For
the
compliance
scenario
that
relies
upon
float/
anchor
supported
nets,
a
total
deployment
period
of
eight
months
(
240
day)
is
assumed.
This
is
equal
to
or
greater
than
most
of
the
deployment
periods
observed
by
EPA.
­
5­
EPA
notes
that
the
Chalk
Point
facility
currently
uses
year
round
deployment
and
avoids
problems
with
ice
in
the
winter
time
by
lowering
the
net
top
to
a
location
below
the
surface.
Prior
to
devising
this
approach,
nets
were
remove
during
the
winter
months.
This
option
is
available
because
the
nets
are
supported
on
pilings.
Thus,
the
surface
support
rope
(
with
floats
removed)
can
be
stretched
between
the
pilings
several
feet
below
the
surface.
Therefore,
a
scenario
where
nets
are
supported
by
pilings
may
include
year
round
deployment
as
was
the
case
for
the
Chalk
Point
Power
Plant.
However,
in
northern
climates
the
sustained
presence
of
thick
ice
during
the
winter
may
prevent
net
removal
and
cleaning
and
therefore,
it
may
still
be
necessary
to
remove
the
nets
during
this
period.

4.1
Capital
Cost
Development
Compliance
costs
are
developed
for
the
two
different
net
scenarios.

Scenario
A
Installation
at
Freshwater
Lake
Using
Anchors
and
Buoys/
Floats
This
scenario
is
intended
for
application
in
freshwater
waterbodies
where
low
water
velocities
and
low
debris
levels
occur
such
as
lakes
and
reservoirs.
This
scenario
is
modeled
on
the
barrier
net
data
from
the
Entergy
Arkansas
Nuclear
One
facility
but
has
been
modified
to
double
the
annual
deployment
period
from
120
days
to
240
days.
Along
with
doubling
the
deployment
period,
the
labor
costs
were
increased
to
include
an
additional
net
removal
and
replacement
step
midpoint
through
this
period.
To
facilitate
the
mid
season
net
replacement,
the
initial
net
capital
costs
will
include
purchase
of
a
replacement
net.

Scenario
B
Installation
Using
Pilings.

This
scenario
is
modeled
after
the
system
used
at
Chalk
Point.
In
this
case
two
nets
are
deployed
in
concentric
semi­
circles
with
the
inner
net
having
a
smaller
mesh
(
0.375
in)
and
the
outer
net
having
a
larger
mesh.
Deployment
is
assumed
to
be
year
round.
A
marine
contractor
performs
all
O&
M,
which
mostly
involves
periodically
removing
and
the
replacing
both
nets
with
nets
they
have
cleaned.
The
initial
capital
net
costs
will
include
purchase
of
a
set
of
replacement
nets.
This
scenario
is
intended
for
application
in
waterbodies
with
low
or
varying
currents
such
as
tidal
rivers
and
estuaries.
Two
different
O&
M
cost
estimates
are
developed
for
this
scenario.
In
one
the
deployment
is
assumed
to
be
year
round
as
is
the
case
at
Chalk
Point.
In
the
second,
the
net
is
deployed
for
only
240
days
being
taken
out
during
the
winter
months.
This
would
apply
to
facilities
northern
regions
where
ice
formation
would
make
net
maintenance
difficult.

Net
Costs
The
capital
costs
for
each
scenario
includes
two
components,
the
net
and
the
support.
The
net
portion
includes
a
rope
and
floats
spaced
along
the
top
and
weights
along
the
bottom
consisting
of
either
a
"
leadline"
or
chain.
If
similar
netting
specifications
are
used
the
cost
of
the
netting
is
generally
proportional
to
the
size
of
the
netting
and
can
be
expressed
in
a
unitized
manner
such
as
"
dollars/
sq
ft."
Table
4­
3
presents
the
reported
net
costs
and
calculated
unit
costs.
While
different
water
depths
will
change
the
general
ratio
of
net
area
to
length
of
rope/
floats
and
bottom
weights
,
the
differences
in
depth
also
result
in
different
float
and
weight
requirements.
For
example,
a
shallower
net
will
­
6­
Facility
Depth
Length
Area
Component
Cost/
net
Cost/
sq
ft
ft
ft
sq
ft
Chalk
Point
27
300
8,100
Replacement
Net
0.675
in.*
$
4,640
$
0.57
27
300
8,100
Replacement
Net
0.375
in.*
$
4,410
$
0.54
Calk
Point
(
equivalent)
10
300
3,000
Replacement
Net*
$
1,510
$
0.50
Entergy
Arkansas
20
250
5,000
Replacement
Net*
$
3,920
$
0.78
Entergy
Arkansas
20
1500
30,000
Net
&
Support
Costs**
$
36,620
$
1.22
Laskin
Energy
Center
16
600
9,600
Net
Costs***
$
1,600
$
0.17
*
Costs
include
floats
and
lead
line
or
chain
and
are
based
on
replacement
costs
plus
12%
shipping.
**
Costs
include
replacement
net
components
plus
anchors,
buoys
&
cable
plus
12%
shipping
***
Cost
based
on
reported
1980
costs
adjusted
to
2002
dollars
plus
12%
for
shipping.
require
more
length
of
surface
rope
and
floats
and
weights
per
unit
net
area
but
a
shallower
depth
net
will
also
exert
less
force
and
require
smaller
floats
and
weights.

EPA
is
using
the
cost
of
nets
in
the
average
depth
range
of
20
to
30
feet
as
the
basis
for
costing.
This
approach
is
consistent
with
the
median
Phase
II
facility
shoreline
intake
depth
of
18
feet
and
median
"
average
bay
depth"
of
20
feet.
While
nets
are
deployed
offshore
in
water
deeper
than
a
shoreline
intake,
costs
are
for
average
depths,
which
include
the
shallow
sections
at
the
ends,
and
net
placement
can
be
configured
to
minimize
depth.
To
see
how
shallower
depths
may
affect
unit
costs,
the
costs
for
a
shallower
10­
foot
net
with
specifications
similar
to
the
Chalk
Point
net
(
depth
of
30
feet)
were
obtained
from
the
facility's
net
supplier.
As
shown
in
Table
4­
3,
the
unit
cost
per
square
foot
for
the
shallower
net
was
less
than
the
deeper
net.
Therefore,
EPA
has
concluded
that
the
use
of
shallower
nets
does
not
increase
unit
costs
and
has
chosen
to
apply
the
unit
costs,
based
on
the
20­
foot
and
30­
foot
depth
nets,
to
shallower
depths.

Table
4­
3
presents
costs
obtained
for
the
net
portion
only
from
the
facilities
that
completed
the
Barrier
Net
Questionnaire.
These
costs
have
been
increased
by
12%
over
what
was
reported
to
include
shipping
costs.
This
12%
value
was
obtained
from
the
Chalk
Point
net
supplier
who
confirmed
that
the
costs
reported
by
Chalk
Point
did
not
include
shipping
(
Murelle
2002)
The
unit
net
costs
range
from
$
0.17/
sq
ft
to
$
0.78/
sq
ft.
Consultation
with
net
vendors
indicates
that
the
barrier
net
specifications
vary
considerably
and
that
there
is
no
standard
approach.
Although
no
net
specification
data
(
besides
mesh
size)
was
submitted
with
the
Laskin
Energy
Center
data,
EPA
has
concluded
that
the
data
for
this
net
probably
represents
lower
strength
netting
which
would
be
suitable
for
applications
where
the
netting
is
not
exposed
to
significant
forces.
Because
the
compliance
cost
scenarios
will
be
applied
to
facilities
with
a
variety
net
strength
requirements,
EPA
has
chosen
to
use
the
higher
net
costs
that
correspond
to
higher
net
strength
requirements.
As
such,
EPA
has
chosen
to
use
the
cost
data
for
the
Chalk
Point
and
Arkansas
Nuclear
One
facilities
as
the
basis
for
each
scenario.

Table
4­
3
Net
Size
and
Cost
Data
Scenario
A
Net
Costs
­
7­
2,000
10,000
50,000
100,000
250,000
500,000
750,000
1,000,000
1,250,000
74
371
1,857
3,714
9,284
18,568
27,852
37,136
46,420
$
149
$
744
$
3,722
$
7,445
$
18,611
$
37,223
$
55,834
$
74,445
$
93,057
$
6,540
$
6,540
$
6,540
$
6,540
$
6,540
$
6,540
$
6,540
$
6,540
$
6,540
$
65
$
324
$
1,619
$
3,238
$
8,096
$
16,191
$
24,287
$
32,383
$
40,478
$
6,754
$
7,608
$
11,881
$
17,223
$
33,247
$
59,954
$
86,661
$
113,368
$
140,075
$
1,351
$
1,522
$
2,376
$
3,445
$
6,649
$
11,991
$
17,332
$
22,674
$
28,015
Total
Capital
Costs
$
8,104
$
9,130
$
14,258
$
20,667
$
39,896
$
71,945
$
103,993
$
136,042
$
168,090
Net
Area
(
sq
ft)
Flow
(
gpm)

Net
Costs
Installation
Costs
Fixed
Installation
Costs
Variable
Total
Direct
Capital
Costs
Indirect
Costs
In
this
scenario
the
net
and
net
support
components
are
included
in
the
unit
costs.
At
the
Arkansas
Nuclear
One
facility
unitized
costs
for
the
net
and
anchors/
buoys
are
$
1.22/
sq
ft
plus
$
0.78/
sq
ft
for
the
replacement
net,
resulting
in
a
total
initial
unit
net
costs
of
$
2.00/
sq
ft
for
both
nets.
Because
the
data
in
Table
4­
3
indicate
that,
if
anything,
unit
costs
for
nets
may
decrease
with
shallower
depths,
EPA
concluded
that
this
unit
cost
was
representative
of
most
of
the
deeper
nets
and
may
slightly
overestimate
the
costs
for
shallower
nets.

Scenario
A
Net
Installation
costs
Installation
costs
for
Arkansas
Nuclear
One
(
Scenario
A)
were
reported
as
$
30,000
(
in
1999
dollars;
$
32,700
when
adjusted
for
inflation
to
2002
dollars)
for
the
30,000
sq
ft
net.
This
included
placement
of
anchors
and
cable
including
labor.
In
order
to
extrapolate
the
installation
costs
for
different
net
sizes,
EPA
has
assumed
that
approximately
20%
($
6,540)
of
this
installation
cost
represents
fixed
costs
(
e.
g.,
mobilization/
demobilization).
The
remainder
($
26,160)
divided
by
the
net
area
results
in
an
installation
unit
cost
of
$
0.87/
sq
ft
to
be
added
to
the
fixed
cost.

Scenario
A
Total
Capital
Costs
Table
4­
4
presents
the
component
and
total
capital
costs
for
Scenario
A.
Indirect
costs
are
added
for
engineering
(
10%)
and
contingency/
allowance
(
10%).
Contractor
labor
and
overhead
are
already
included
in
the
component
costs.
Because
most
of
the
operation
occurs
offshore
no
cost
for
sitework
are
included.

Table
4­
4
Capital
Costs
for
Scenario
A
Fish
Barrier
Net
With
Anchors/
Buoys
as
Support
Structure
Scenario
B
Net
Costs
In
this
scenario
the
net
costs
are
computed
separately
from
the
net
support
(
pilings)
costs.
In
this
scenario
there
are
two
separate
nets
and
an
extra
set
of
replacement
nets
for
each.
This,
the
unit
costs
for
the
nets
will
be
two
times
the
sum
of
the
units
net
costs
for
each
of
the
large
and
small
mesh
nets.
As
shown
in
Table
4­
3,
the
unit
costs
for
each
net
was
$
0.57/
sq
ft
and
$
0.54/
sq
ft
resulting
in
a
total
cost
for
all
four
nets
of
$
2.24/
sq
ft
for
the
area
of
a
single
net.
­
8­
Water
Depth
Total
Pile
Length
Cost
Per
Pile
Flow
Per
20
ft
Net
Section
Flow
Per
20
ft
Net
Section
Fixed
Cost
Mobilizati
on
Ft
Ft
cfs
gpm
10
22.0
$
627
12
5,386
$
2,325
20
40.0
$
1,140
24
10,771
$
2,325
30
56.0
$
1,596
36
16,157
$
2,325
Scenario
B
Installation
Costs
Installation
costs
were
not
provided
for
the
Chalk
Point
facility.
Initial
net
installation
is
assumed
to
be
performed
by
the
O&
M
contractor
and
is
assumed
to
be
a
fixed
cost
regardless
of
net
size.
EPA
assumed
the
initial
installation
costs
to
be
two­
thirds
of
the
contractor,
single
net
replacement
job
cost
($
933).

Scenario
B
Piling
Costs
The
cost
for
the
pilings
at
the
Chalk
Point
facility
were
not
provided.
The
piling
costs
for
scenario
B
is
based
primarily
on
the
estimated
cost
for
installing
two
concentric
set
of
treated
wooden
pilings
with
a
spacing
of
20
ft
between
pilings.
To
see
how
water
depth
affects
piling
costs,
separate
costs
were
developed
at
water
depths
of
10
feet,
20
feet,
and
30
feet.
Piling
costs
are
based
on
the
following
assumptions:

°
Costs
for
pilings
is
based
on
a
unit
cost
of
$
24.50/
ft
of
piling
(
Costworks
2001)
°
Piling
installation
mobilization
costs
are
equal
to
$
2,325
based
on
a
mobilization
rate
of
$
46.50/
mile
for
barge
mounted
pile
driving
equipment
(
Costworks
2001)
and
an
assumed
distance
of
50
miles
°
Each
pile
length
includes
the
water
depth
plus
a
6­
foot
extension
above
the
water
surface
plus
a
penetration
depth
(
at
two­
thirds
the
water
depth);
the
calculated
length
was
rounded
up
to
the
next
even
whole
number
°
The
two
concentric
nets
are
nearly
equal
in
length
with
one
pile
for
every
20
feet
in
length
and
one
extra
pile
to
anchor
the
end
of
each
net.

Table
4­
5
presents
the
individual
pile
costs
and
intake
flow
for
each
net
section
between
two
pilings
(
at
0.06
fps).

Table
4­
5
Pile
Costs
and
Net
Section
Flow
Tables
4­
6,
4­
7,
and
4­
8
present
the
total
capital
costs
and
cost
components
for
the
installed
nets
and
pilings.
Indirect
costs
are
added
for
engineering
(
10%)
and
contingency/
allowance
(
10%).
Contractor
labor
and
overhead
are
already
included
in
the
component
costs.
Because
most
of
the
operation
occurs
offshore
no
cost
for
sitework
are
included.
The
costs
were
derived
for
nets
with
multiple
20
ft
sections.
Because
the
net
costs
are
derived
such
that
the
cost
equations
are
linear
with
­
9­
2
4
8
12
25
50
75
100
200
6
10
18
26
52
102
152
202
402
40
80
160
240
500
1000
1500
2000
4000
400
800
1,600
2,400
5,000
10,000
15,000
20,000
40,000
10,771
21,542
43,085
64,627
134,640
269,280
403,920
538,560
1,077,120
$
6,429
$
9,165
$
14,637
$
20,109
$
37,893
$
72,093
$
106,293
$
140,493
$
277,293
$
1,380
$
1,827
$
2,721
$
3,614
$
6,519
$
12,106
$
17,692
$
23,279
$
45,624
$
7,809
$
10,992
$
17,358
$
23,723
$
44,412
$
84,199
$
123,985
$
163,772
$
322,917
$
1,562
$
2,198
$
3,472
$
4,745
$
8,882
$
16,840
$
24,797
$
32,754
$
64,583
$
9,371
$
13,190
$
20,829
$
28,468
$
53,295
$
101,039
$
148,782
$
196,526
$
387,501
Net
Area
(
sq
ft)

Indirect
Costs
Total
Capital
Costs
Flow
(
gpm)
Total
Piling
Cost
Net
Costs
Total
Direct
Costs
Number
of
20
ft
Sections
Total
Number
of
Pilings
Single
Net
Length
(
ft)

2
4
8
12
25
50
75
100
6
10
18
26
52
102
152
202
40
80
160
240
500
1000
1500
2000
800
1600
3200
4800
10000
20000
30000
40000
21,542
43,085
86,170
129,254
269,280
538,560
807,840
1,077,120
$
9,165
$
13,725
$
22,845
$
31,965
$
61,605
$
118,605
$
175,605
$
232,605
$
1,827
$
2,721
$
4,508
$
6,296
$
12,106
$
23,279
$
34,452
$
45,624
$
10,992
$
16,446
$
27,353
$
38,261
$
73,711
$
141,884
$
210,057
$
278,229
$
2,198
$
3,289
$
5,471
$
7,652
$
14,742
$
28,377
$
42,011
$
55,646
$
13,190
$
19,735
$
32,824
$
45,913
$
88,453
$
170,260
$
252,068
$
333,875
Net
Area
(
sq
ft)
Single
Net
Length
(
ft)

Total
Direct
Costs
Indirect
Costs
Total
Capital
Costs
Flow
(
gpm)
Total
Piling
Cost
Net
Costs
Number
of
20
ft
Sections
Total
Number
of
Pilings
2
4
8
12
25
50
75
6
10
18
26
52
102
152
40
80
160
240
500
1000
1500
1,200
2,400
4,800
7,200
15,000
30,000
45,000
32,314
64,627
129,254
193,882
403,920
807,840
1,211,760
$
9,576
$
15,960
$
28,728
$
41,496
$
82,992
$
162,792
$
242,592
$
2,274
$
3,614
$
6,296
$
8,977
$
17,692
$
34,452
$
51,211
$
11,850
$
19,574
$
35,024
$
50,473
$
100,684
$
197,244
$
293,803
$
2,370
$
3,915
$
7,005
$
10,095
$
20,137
$
39,449
$
58,761
Total
Capital
Costs
$
14,220
$
23,489
$
42,029
$
60,568
$
120,821
$
236,692
$
352,563
Net
Costs
Total
Direct
Costs
Indirect
Costs
Total
Number
of
Pilings
Single
Net
Length
(
ft)

Flow
(
gpm)
Total
Piling
Cost
Number
of
20
ft
Sections
Net
Area
(
sq
ft)
respect
to
flow,
the
maximum
number
of
sections
shown
are
selected
so
they
cover
a
similar
flow
range.
Values
that
exceed
this
range
can
use
the
same
cost
equation.

Table
4­
6
Capital
Costs
for
Fish
Barrier
Net
With
Piling
Support
Structure
for
10
Ft
Deep
Nets
Table
4­
7
Capital
Costs
for
Fish
Barrier
Net
With
Piling
Support
Structure
for
20
Ft
Deep
Nets
Table
4­
8
Capital
Costs
for
Fish
Barrier
Net
With
Piling
Support
Structure
for
30
Ft
Deep
Nets
­
10­
Figure
4­
1
presents
the
total
capital
costs
for
scenarios
A
and
B
from
Tables
4­
4
through
4­
8,
plotted
against
design
flow.
Figure
4­
1
also
presents
the
best­
fit
linear
equations
used
top
estimate
compliance
costs.
EPA
notes
that
pilings
for
shallower
depths
costed
out
more,
due
to
the
need
for
many
more
pilings.
Scenario
B
costs
for
10­
foot
deep
nets
will
be
applied
wherever
the
intake
depth
is
less
than
12
ft.
For
scenario
B
applications
in
water
much
deeper
than
12
feet,
EPA
will
use
the
cost
equation
for
20­
foot
deep
nets.

3.2
O&
M
Costs
Development
Scenario
A
O&
M
Costs
­
Float/
Anchor
Supported
Nets
Barrier
net
O&
M
costs
generally
include
costs
for
replacement
netting,
labor
for
net
inspection,
repair,
and
cleaning,
and
labor
for
net
placement
and
removal.
The
Arkansas
Nuclear
One
facility
supplied
data
that
estimate
all
three
components
for
its
1500
ft
long
by
20
ft
deep
net
located
on
a
reservoir.
Net
deployment,
however,
was
for
only
a
120­
day
period.
This
net
is
installed
in
November
and
removed
in
March
(
in­
place
for
120
days
total).
Each
year
two
250­
foot
sections
of
the
net
(
one­
third
of
the
total)
are
replaced
due
to
normal
wear
and
tear.
EPA
assumes
the
labor
rate
is
similar
to
the
estimate
for
traveling
screen
maintenance
labor
($
41.10/
hr).
The
reported
Arkansas
Nuclear
One
O&
M
labor
requirements
includes
3
hrs
per
day
during
the
time
the
net
is
deployed
for
inspection
&
cleaning
by
personnel
on
a
boat
(
calculated
at
$
14,800).
This
involves
lifting
and
partially
cleaning
the
nets
on
a
periodic
basis.
Labor
to
deploy
and
remove
the
net
was
reported
at
240
hrs
(
calculated
at
$
9,860).
Two
sections
of
the
six
total
net
sections
were
replaced
annually
at
a
cost
of
$
7,830
total
(
including
shipping).
Total
annual
O&
M
costs
are
calculated
to
be
$
32,500.

Because
other
facilities
on
lakes
reported
longer
deployment
periods
(
generally
when
ice
is
not
present),
EPA
chose
to
adjust
O&
M
costs
to
account
for
longer
deployment.
EPA
chose
to
base
O&
M
costs
for
scenario
A
on
a
deployment
period
of
240
days
(
approximately
double
the
Arkansas
Nuclear
One
facility
deployment
period).
EPA
also
added
costs
for
an
additional
net
removal
and
deployment
step
using
the
second
replacement
net
midway
through
the
annual
deployment
period.
The
result
is
a
calculated
annual
O&
M
cost
of
$
57,200.

Scenario
B
O&
M
Costs
­
Piling
Supported
Nets
Nearly
all
of
the
O&
M
labor
for
Chalk
Point
facility
is
performed
by
a
marine
contractor
who
charges
$
1,400
per
job
to
simultaneously
remove
the
existing
net
and
replace
it
with
a
cleaned
net.
This
is
done
with
two
boats
where
one
boat
removes
the
existing
net
followed
quickly
by
the
second
that
places
the
cleaned
net
keeping
the
open
area
between
nets
minimized
.
The
contractors
fee
includes
cleaning
the
removed
nets
between
jobs.
This
net
replacement
is
performed
about
52
to
54
times
per
years.
It
is
performed
about
twice
per
week
during
the
summer
and
once
every
two
weeks
during
the
winter.
The
facility
relies
upon
the
contractor
to
monitor
the
net.
Approximately
one
third
of
the
nets
are
replaced
each
year,
resulting
in
a
net
replacement
cost
of
$
9,050.

Using
an
average
of
53
contractor
jobs
per
year
and
a
net
replacement
cost
of
$
9,050
the
resulting
annual
O&
M
cost
was
$
83,250.
EPA
notes
that
some
facilities
that
employ
scenario
B
technology
may
choose
to
remove
the
nets
during
the
winter.
As
such,
EPA
has
also
estimated
the
scenario
B
­
11­
Deploym
ent
Net
Replaceme
nt
O&
M
Labor
Model
Facility
O&
M
Fixed
Cost
Variable
Costs
Unit
Variable
O&
M
Costs
Days
$/
sq
ft
Scenario
A
240
$
7,830
$
57,200
$
57,200
$
11,440
$
45,760
$
1.53
Scenario
B
365
$
9,050
$
74,200
$
83,250
$
16,650
$
66,600
$
2.47
Scenario
B
240
$
9,050
$
60,200
$
69,250
$
13,850
$
55,400
$
2.05
2,000
10,000
50,000
100,000
250,000
500,000
750,000
1,000,000
1,250,000
Net
Area
(
sq
ft)
74
371
1,857
3,714
9,284
18,568
27,852
37,136
46,420
Scenario
A
240
days
$
11,553
$
12,006
$
14,272
$
17,104
$
25,601
$
39,762
$
53,924
$
68,085
$
82,246
Scenario
B
365
days
$
16,833
$
17,566
$
21,230
$
25,810
$
39,551
$
62,451
$
85,352
$
108,252
$
131,153
Scenario
B
240
days
$
14,002
$
14,612
$
17,660
$
21,470
$
32,899
$
51,949
$
70,998
$
90,048
$
109,097
Flow
(
gpm)
O&
M
costs
based
on
a
deployment
period
of
approximately
240
days
by
reducing
the
estimated
number
of
contractor
jobs
from
53
to
43
(
deducting
10
jobs
using
the
winter
frequency
of
roughly
1
job
every
2
weeks).
The
resulting
O&
M
costs
are
shown
in
Tables
4­
9
and
4­
10.

EPA
notes
that
other
O&
M
costs
reported
in
literature
are
often
less
than
what
is
shown
in
Table
4­
9.
For
example,
1985
O&
M
cost
estimates
for
the
JP
Pulliam
plant
($
7,500/
year,
adjusted
to
2002
dollars)
calculate
to
$
11,800
for
a
design
flow
roughly
half
that
of
Arkansas
Entergy.
This
suggests
the
scenario
A
and
B
estimates
represent
the
high
end
of
the
range
of
barrier
net
O&
M
costs.
Other
O&
M
estimates,
however,
do
not
indicate
the
cost
components
that
are
included
and
may
not
represent
all
cost
components.

In
order
to
extrapolate
costs
for
other
flow
rates,
EPA
has
assumed
that
roughly
20%
of
the
Scenario
A
and
B
O&
M
costs
represent
fixed
costs.
Table
4­
9
presents
the
fixed
and
unit
costs
based
on
this
assumption
for
both
scenarios.

Table
4­
9
Cost
Basis
for
O&
M
Costs
Table
4­
10
presents
the
calculated
O&
M
costs
based
on
the
cost
factors
in
Table
4­
9
and
Figure
4­
2
presents
the
plotted
O&
M
costs
and
the
linear
equations
fitted
to
the
cost
estimates.

Table
4­
10
Annual
O&
M
Cost
Estimates
3.4
Nuclear
Facilities
Even
though
the
scenario
A
costs
are
modeled
after
the
barriers
nets
installed
at
a
nuclear
facility,
the
higher
unit
net
costs
cited
by
the
Arkansas
Nuclear
One
facility
include
components
that
are
not
included
with
the
non­
nuclear
Chalk
Point
nets
and
thus
the
differences
may
be
attributed
to
­
12­
equipment
differences
and
not
differences
between
nuclear
and
non­
nuclear
facilities.
In
addition,
the
labor
rates
used
for
scenario
A
and
B
O&
M
were
for
non­
nuclear
facilities.
Because
the
function
of
barrier
nets
is
purely
for
environmental
benefit,
and
not
critical
to
the
continued
function
of
the
cooling
system
(
as
would
be
technologies
such
as
traveling
screens).
EPA
does
not
believe
that
a
much
more
rigorous
design
is
warranted
at
nuclear
facilities.
However,
higher
labor
rates
plus
greater
paperwork
and
security
requirements
at
nuclear
facilities
should
result
in
higher
costs.
As
such,
EPA
has
concluded
that
the
capital
costs
for
nuclear
facilities
should
be
increased
by
a
factor
of
1.58
(
lower
end
of
range
cited
in
passive
screen
section).
Because
O&
M
costs
rely
heavily
on
labor
costs,
EPA
has
concluded
that
the
O&
M
costs
should
be
increased
by
a
factor
of
1.24
(
based
on
nuclear
vs
non­
nuclear
operator
labor
costs).

3.3
Application
Fish
barrier
net
technology
will
augment,
but
not
replace,
the
function
of
any
existing
technology.
Therefore,
the
calculated
net
O&
M
costs
will
include
the
O&
M
costs
described
here
without
any
deductions
for
reduction
in
existing
technology
O&
M
costs.
Fish
barrier
nets
may
not
be
applicable
in
locations
where
they
would
interfere
with
navigation
channels
or
boat
traffic.

Fish
barrier
nets
require
low
waterbody
currents
in
order
to
avoid
becoming
plugged
with
debris
that
could
collapse
the
net.
Such
conditions
can
be
found
in
most
lakes
and
reservoirs,
as
well
as
some
tidal
waterbodies
such
as
tidal
rivers
and
estuaries.
Placing
barrier
nets
in
a
location
with
sustained
lateral
currents
in
one
direction
may
cause
problems
because
the
section
of
net
facing
the
current
will
continually
collect
debris
at
higher
rate
than
the
remainder
of
the
net.
In
this
case,
net
maintenance
cleaning
efforts
must
be
able
to
keep
up
with
debris
accumulation.
As
such,
barrier
nets
are
suitable
for
intake
locations
that
are
sheltered
from
currents,
e.
g.,
locations
within
an
embayment,
bay,
or
cove.
On
freshwater
rivers
and
streams
only
those
facilities
within
an
embayment,
bay,
or
cove
will
be
considered
as
candidates
for
barrier
nets..
The
sheltered
area
needs
to
be
large
enough
for
the
net
sizes
described
above.
The
fish
barrier
net
designs
considered
here
would
not
be
suitable
for
waterbodies
with
the
strong
wave
action
typically
found
in
ocean
environments.

Scenario
A
is
most
suitable
for
lakes
and
reservoirs
where
water
currents
are
low
or
almost
nonexistent.
Scenario
B
is
more
suitable
for
tidal
waterbodies
and
any
other
location
where
higher
quantities
of
debris
and
light
or
fluctuating
currents
may
be
encountered.
In
northern
regions
where
formation
of
thick
ice
in
winter
would
prevent
access
to
the
nets,
and
scenario
B
may
be
applied,
the
scenario
B
O&
M
costs
for
a
240­
day
deployment
should
be
used.
However,
because
this
scenario
results
in
reduced
costs,
EPA
has
chose
to
apply
the
scenario
B
365
days
deployment
for
all
facilities
in
suitable
waterbodies.

EPA
notes
that
nets
with
net
velocities
higher
than
0.06
fps
have
been
successfully
employed
(
EPRI
1985).
While
such
nets
will
be
smaller
than
those
described
here,
they
will
accumulate
debris
at
a
faster
rate.
Because
the
majority
of
the
O&
M
costs
are
related
to
cleaning
nets,
EPA
expects
the
increase
in
frequency
of
cleaning
smaller
nets
will
be
offset
by
the
smaller
net
size
such
that
the
smaller
nets
should
require
similar
costs
to
maintain.
­
13­
Facilities
with
Canals
Most
facilities
with
canals
have
in­
canal
velocities
of
between
0.5
and
1
fps
based
on
average
flow.
These
velocities
are
an
order
of
magnitude
greater
than
the
design
net
velocity
used
here.
If
nets
with
mesh
sizes
in
the
range
considered
here
were
placed
within
the
canals
they
will
likely
experience
problems
with
debris.
Therefore,
if
barrier
nets
are
used
at
facilities
with
canals,
the
net
would
need
to
be
placed
in
the
waterbody
just
outside
the
canal
entrance.

References
EPA.
Responses
to
Fish
Barrier
Net
Questionnaires.
2002.(
Update
memo
from
Candace)

Taft,
E.
P.
"
Fish
Protection
Technologies:
A
Status
Report."
Alden
Research
laboratory,
Inc.
1999.

Hutcheson,
J.
B.
Jr.
Matousak,
J.
A.
"
Evaluation
of
a
Barrier
Net
Used
to
Mitigate
Fish
Impingement
at
a
Hudson
River
Power
Plant."
American
Fisheries
Society
Monograph
4:
208­
285.
1988
Murelle,
D.
Nylon
Nets
Company.
Telephone
Contact
Report
with
John
Sunda,.
SAIC.
Regarding
cost
and
design
information
for
fish
barrier
nets.
November
5,
2002.

Langley,
P.
Chalk
Point
Power
Station.
Telephone
Contact
Report
with
John
Sunda,.
SAIC.
Regarding
fish
barrier
net
design,
operation,
and
O&
M
costs.
November
4,
2002.

ASCE.
Design
of
Water
Intake
Structures
for
Fish
Protection.
American
Society
of
Civil
Engineers.
1982.

EPRI.
Intake
Research
Facilities
Manual.
Prepared
by
Lawler,
Matusky
&
Skelly
Engineers,
Pearl
River,
New
York,
for
Electric
Power
Research
Institute.
EPRI
CS­
3976.
May
1985.

Costworks
2001.
­
14­
Figure
4­
1
Total
Capital
Costs
for
Fish
Barrier
Nets
y
=
0.3038x
+
6645.6
R
2
=
1
y
=
0.1282x
+
7848
R
2
=
1
y
=
0.3546x
+
5551.2
R
2
=
1
y
=
0.2869x
+
4950
R
2
=
1
$
0
$
50,000
$
100,000
$
150,000
$
200,000
$
250,000
$
300,000
$
350,000
$
400,000
$
450,000
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
1,400,000
Scenario
A
Barrier
Net
Scenario
B
Net
at
10
ft
Depth
Scenario
B
Net
at
20
ft
Depth
Scenario
B
Net
at
30
ft
­
15­
Figure
4­
2
Barrier
Net
Annual
O&
M
Costs
y
=
0.0916x
+
16650
R
2
=
1
y
=
0.0566x
+
11440
R
2
=
1
y
=
0.0762x
+
13850
R
2
=
1
$
0
$
20,000
$
40,000
$
60,000
$
80,000
$
100,000
$
120,000
$
140,000
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
1,400,000
Design
Flow
(
gpm)

Annual
O&

M
Costs
Scenario
A
Scenario
B
365
Days
Scenario
B
240
days
­
16­
