Document ID: EPA-HQ-OW-2002-0049-0009
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2003-03-19T05:00Z

­
1­
316b
Phase
II
Cost
Module
1.0
Submerged
Passive
Intakes
The
modules
described
in
this
section
involve
submerged
passive
intakes,
and
address
both
adding
technologies
to
the
inlet
of
existing
submerged
intakes
and
converting
shoreline
based
intakes
(
e.
g.,
shoreline
intakes
with
traveling
screens)
to
submerged
offshore
intakes
with
added
passive
inlet
technologies.
The
passive
inlet
technologies
that
are
considered
include
passive
screens
and
velocity
caps.
All
intakes
relocated
from
shore­
based
to
submerged
offshore
are
assumed
to
employ
either
a
velocity
cap
or
passive
screens.
The
module
discussing
velocity
caps
begins
in
section
3.0.

1.1
Relocated
Shore­
based
Intake
to
Submerged
Near­
shore
and
Offshore
with
Fine
Mesh
Passive
Screens
at
Inlet
This
section
contains
three
sections.
The
first
section
discusses
the
selection
and
deriviation
of
cost
input
values.
This
discussion
includes:
passive
screen
technology
selection,
selection
of
flow
values,
intake
configurations,
connecting
walls,
and
connecting
pipes.
The
second
section
discusses
cost
development
for:
screen
construction
materials,
connecting
walls,
pipe
manifolds,
airburst
systems,
indirect
costs,
nuclear
facilities,
O&
M
costs,
construction­
relatred
downtime.
The
third
section
presents
a
discussion
of
the
applicability
of
this
cost
module.

1.1.1
Selection/
Deriviation
of
Cost
Input
Values
Passive
Screen
Technology
Selection
Passive
screens
come
in
one
of
three
general
configurations:
flat
panel,
cylindrical,
and
cylindrical
T­
type.
Only
passive
screens
constructed
of
welded
wedgewire
were
considered
due
to
the
improved
performance
of
wedgewire
with
respect
to
debris.
After
discussion
with
vendors
concerning
the
attributes
and
prevalence
of
the
various
passive
screen
technology
configurations,
EPA
selected
the
T­
screen
configuration
as
the
most
versatile
with
respect
to
a
variety
of
local
intake
waterbody
attributes.
The
most
important
screen
attribute
was
the
requirement
for
screen
placement.
Both
cylindrical
and
T­
screens
allow
for
placement
of
the
screens
extending
into
the
waterbody,
which
allows
for
debris
to
migrate
away
from
the
screens
once
dislodged.
T­
screens
produce
greater
flow
per
screen
unit
and
thus
were
chosen
because
they
are
more
practical
in
multi­
screen
installations.
Due
to
the
potential
for
build­
up
and
plugging
by
debris,
passive
screens
are
usually
installed
with
an
airburst
backwash
system.
This
system
includes
a
compressor,
an
accumulator
(
aka
receiver),
controls,
a
distributor
and
air
piping
that
directs
a
burst
of
air
into
each
screen.
The
air
burst
produces
a
rapid
backflow
through
the
screen;
this
air­
induced
turbulence
dislodges
accumulated
debris,
which
then
drifts
away
from
the
screen
unit.
Vendors
claimed
(
although
with
minimal
or
no
supporting
data)
that
only
very
stagnant
water
with
a
high
debris
load
or
very
shallow
water
(<
2
ft
deep)
would
prevent
use
of
this
screen
technology.
Areas
with
low
water
velocities
would
simply
require
more
frequent
airburst
backwashes,
and
few
facilites
are
constrained
by
water
depths
as
shalllow
as
2
feet..
­
2­
SCREEN
SIZE
CAPACIT
Y
SLOT
SCREEN
LENGTH
AIRBURST
PIPE
DIAMETER
SCREEN
OUTLET
DIAMETER
SCREEN
WEIGHT
GPM
MM
FT
INCHES
INCHES
LBS
T24
2,500
1.78
6.3
2
18
375
T36
5,700
1.78
9.3
3
30
1,050
T48
10,000
1.78
13.3
4
36
1,600
T60
15,800
1.78
16.6
6
42
2,500
T72
22,700
1.78
19.8
8
48
4,300
T84
31,000
1.78
22.9
10
60
6,000
T96
40,750
1.78
26.4
12
72
NA
*
Source:
Johnson
Screen
­
Brochure
2002
­
High
Capacity
Screen
at
50%
Open
Area
PASSIVE
T­
SCREEN
DESIGN
SPECIFICATIONS
While
there
are
waterbodies
with
levels
of
debris
low
enough
to
preclude
installation
of
an
airburst
system,
EPA
has
chosen
to
include
an
airburst
backwash
system
with
each
T­
screen
installation
as
a
prudent
precaution.
The
capital
cost
of
the
airburst
backwash
system
is
a
substantial
component,
particularly
in
offshore
applications,
because
of
the
need
to
install
a
separate
air
supply
pipe
from
the
shoreline
air
supply
to
each
screen
or
group
of
smaller
screens.
Thus,
the
assumption
that
airburst
backwash
systems
are
needed
in
all
applications
is
considered
as
part
of
an
overall
cost
approach
that
increases
projected
capital
costs
to
the
industry
to
develop
a
high­
side
cost
estimate.

T­
screens
ranging
in
diameter
from
2
feet
(
T24)
to
8
feet
(
T96),
in
one­
foot
intervals,
are
used
in
the
analysis.
The
costs
provided
are
for
screens
with
a
slot
size
of
approximately
1.75
mm.
The
design
flow
values
used
for
each
size
screen
correspond
to
wedgewire
T­
screens
with
a
through
screen
velocity
of
0.5
fps.
Table
1­
1
presents
design
specifications
for
the
wedgewire
T­
screens
costed.

TABLE
1­
1
Selection
of
Flow
Values
The
flow
values
used
in
the
development
of
cost
equations
range
from
a
design
flow
of
2,500
gpm
(
which
is
the
design
flow
for
the
smallest
screen
(
T24)
for
which
costs
were
obtained)
to
a
flow
of
163,000
gpm
(
which
is
equivalent
to
the
design
flow
of
four
T96
screens).
The
higher
flow
was
chosen
because
it
was
equal
to
the
flow
in
a
10­
foot
diameter
pipe
at
a
pipe
velocity
of
just
4.6
fps.
A
10­
foot
diameter
pipe
was
chosen
as
the
largest
size
for
individual
pipes
because
this
size
was
within
the
range
of
sizes
that
are
capable
of
being
installed
using
the
technology
assumed
in
the
cost
model.
Additionally,
the
need
to
spread
out
the
multiple
screens
across
the
bottom
is
facilitated
by
multiple
pipes.
One
result
of
this
decision
is
that
for
facilities
with
design
flows
significantly
greater
than
163,000
gpm,
the
total
costs
are
based
on
dividing
the
intake
into
multiple
units
and
summing
the
costs
of
each.

Intake
Configuration
­
3­
The
scenarios
evaluated
in
this
analysis
are
based
on
retrofit
construction
in
which
the
new
passive
screens
are
connected
to
the
existing
intake
by
newly
installed
pipes,
while
the
existing
intake
pumps
and
pump
wells
remain
intact
and
functional.
The
cost
scenario
also
retains
the
existing
screen
wells
and
bays,
since
in
most
cases
they
are
connected
directly
to
the
pump
wells.
Facilities
may
retain
the
existing
traveling
screens
as
a
backup,
but
the
retention
of
functioning
traveling
screens
is
not
necessary.
No
operating
costs
are
considered
for
the
existing
screens
since
they
are
not
needed.
Even
if
they
are
retained,
there
should
be
almost
no
debris
to
collect
on
their
surfaces.
Thus,
they
would
only
need
to
be
operated
on
an
infrequent
basis
to
ensure
they
remain
functional.

The
new
passive
screens
are
placed
along
the
bottom
of
the
waterway
in
front
of
the
existing
intake
and
connected
to
the
existing
intake
with
pipes
that
are
laid
either
directly
on
or
buried
below
the
stream
bed.
The
key
components
of
the
retrofit
are:
the
transition
connection
to
the
existing
intake,
the
connecting
pipe
or
pipes
(
a.
k.
a.
manifold
or
header),
the
passive
screens
or
velocity
cap
located
at
the
pipe
inlet,
and
if
passive
screens
are
used,
the
backwash
system.

At
most
of
the
T­
screen
retrofit
installations,
particularly
those
requiring
more
than
one
screen,
the
installation
of
passive
T­
screens
will
likely
require
relocating
the
intake
to
a
near­
shore
location
or
to
a
submerged
location
farther
offshore,
depending
on
the
screen
spacing,
water
depth,
and
other
requirements.
An
exception
would
be
smaller
flow
intakes
where
the
screen
could
be
connected
directly
to
the
front
of
the
intake
with
a
minimal
pipe
length
(
e.
g.,
half
screen
diameter).
Other
considerations
that
may
make
locating
farther
offshore
necessary
or
desirable
include:
the
availability
of
cooler
water,
lower
levels
of
debris,
and
fewer
aquatic
organisms
for
placements
outside
the
littoral
zone.
As
such,
costs
have
been
developed
for
a
series
of
distances
from
the
shoreline.

In
retrofits
where
flow
requirements
do
not
increase,
EPA
has
found
existing
pumps
and
pump
wells
can
be,
and
have
been,
retained
as
part
of
the
new
system.
The
cost
scenarios
assume
flow
volumes
do
not
increase.
Thus,
using
existing
pumps
and
pump
wells
is
both
feasible
and
economically
prudent.
There
are,
however,
two
concerns
regarding
the
use
of
existing
pumps
and
pump
wells.
One
is
the
degree
of
additional
head
loss
associated
with
the
new
pipes
and
screens.
The
second
is
the
intake
downtime
needed
to
complete
the
installation
and
connection
of
the
new
passive
screen
system
or
velocity
cap.
The
downtime
considerations
are
discussed
later
in
a
separate
section.

The
additional
head
losses
associated
with
the
passive
screen
retrofit
scenario
described
here
include
the
frictional
losses
in
the
connecting
pipes
and
the
losses
through
the
screen
surface.
If
the
new
connecting
pipe
velocities
are
kept
low
(
e.
g.,
5
fps
is
used
in
this
analysis),
then
the
head
loss
in
the
extension
pipe
should
remain
low
enough
to
allow
the
existing
pumps
to
function
properly
in
most
instances.
For
example,
a
48­
inch
diameter
pipe
at
a
flow
of
2,800
gpm
(
average
velocity
of
4.96
fps)
will
have
a
head
loss
of
2.31
feet
of
water
per
1,000­
foot
pipe
length
(
Shaw
and
Loomis
1970).
The
new
passive
screens
will
contribute
an
additional
0.5
to
0.75
feet
of
water
to
this
head
loss,
which
will
further
increase
when
the
screen
is
clogged
by
debris
(
Screen
Services
2002).
In
fact,
the
rate
at
which
this
screen
head
loss
increases
due
to
debris
build­
up
will
dictate
the
frequency
of
use
of
the
air
backwash.
Pump
wells
are
generally
equipped
with
alarms
that
warn
of
low
water
levels
due
to
increased
head
loss
through
the
intake.
If
the
screen
becomes
plugged
to
the
point
where
backwash
fails
to
maintain
the
necessary
water
level
in
the
pump
well,
the
pump
flow
rate
must
be
reduced.
­
4­
This
reduction
may
result
in
a
derating
or
shut
down
of
the
associated
generating
unit.
Lower
than
normal
surface
water
levels
may
exacerbate
this
problem.

In
terms
of
required
dimensions
for
installation,
Table
1­
1
shows
screen
length
is
just
over
three
times
the
diameter
and
each
screen
requires
a
minimum
clearance
of
one­
half
diameter
on
all
sides
except
the
ends.
Thus,
an
8­
foot
diameter
screen
will
require
a
minimum
water
depth
of
16
feet
at
the
screen
location
(
four
feet
above,
four
feet
below,
and
eight
feet
for
the
screen
itself).
It
is
recommended
that
T­
screens
be
oriented
such
that
the
long
axis
is
parallel
to
the
waterbody
flow
direction.
T­
screens
can
be
arranged
in
an
end­
to­
end
configuration
if
necessary.
However,
using
a
greater
separation
above
the
minimum
will
facilitate
dispersion
of
the
released
accumulated
debris
during
screen
backwashes.

In
the
retrofit
scenario
described
here,
screen
size
and
number
are
based
on
using
a
single
screen
with
the
screen
size
increasing
with
increasing
design
flows.
When
flow
exceeds
the
capacity
of
a
single
T96
screen,
multiple
T96
screens
are
used.
This
retrofit
scenario
also
assumes
the
selected
screen
location
has
a
minimum
water
depth
equal
to
or
greater
than
the
values
shown
in
Table
1­
2.

TABLE
1­
2
MINIMUM
DEPTH
AT
SCREEN
LOCATION
FOR
SINGLE
SCREEN
SCENARIO
Flow
Screen
Size
Minimum
Depth
2,500
gpm
T24
4
ft
5,700
gpm
T36
6
ft
10,000
gpm
T48
8
ft
15,800
gpm
T60
10
ft
22,700
gpm
T72
12
ft
31,000
gpm
T84
14
ft
40,750
gpm
T96
16
ft
>
40,750
gpm
Multiple
T96
16
ft
In
certain
instances
water
depth
or
other
considerations
will
require
using
a
greater
number
of
smaller
diameter
screens.
For
these
cases
the
same
size
header
pipe
can
be
used,
but
the
intake
will
require
either
more
branched
piping
or
multiple
connections
along
the
header
pipe.

Connecting
Wall
The
retrofit
of
passive
T­
screen
technology
where
the
existing
pump
well
and
pumps
are
retained
will
require
a
means
of
connecting
the
new
screen
pipes
to
the
pump
well.
Pump
wells
that
are
an
­
5­
integral
part
of
shoreline
intakes
(
often
the
case)
will
require
installing
a
wall
in
front
of
the
existing
intake
pump
well
or
screen
bays.
This
wall
serves
to
block
the
existing
intake
opening
and
to
connect
the
T­
screen
pipe(
s)
to
the
existing
intake
pump
wells.
In
the
proposed
cost
scenario,
the
T­
screen
pipe(
s)
can
be
attached
directly
to
holes
passing
through
the
wall
at
the
bottom.

Two
different
types
of
construction
have
been
used
in
past
retrofits
or
have
been
proposed
in
feasibility
studies.
In
one,
a
wall
constructed
of
steel
plates
is
attached
to
and
covers
the
front
of
each
intake
bay
or
pump
well,
such
that
one
or
more
connecting
pipes
feed
water
into
each
screen
bay
or
pump
well
individually.
In
this
scenario,
a
single
steel
plate
or
several
interlocking
plates
are
affixed
to
the
front
of
the
screen
bays
by
divers,
and
the
T­
screen
pipe
manifolds
are
then
attached
to
flanged
fittings
welded
at
the
bottom
of
the
plate(
s).
For
smaller
flow
intakes
that
require
a
single
screen,
this
may
be
the
best
configuration
since
the
screen
can
be
attached
directly
to
the
front
of
the
intake
minimizing
the
intrusion
of
the
retrofit
operation
into
the
waterway.

In
the
second
scenario,
an
interlocking
sheet
pile
wall
is
installed
in
the
waterbody
directly
in
front
of,
and
running
the
length
of,
the
existing
intake.
Individual
screen
manifold
pipe(
s)
are
attached
to
holes
cut
in
the
bottom
along
the
length
of
the
sheet
pile
wall.
In
this
case,
a
common
plenum
between
the
sheet
pile
wall
and
the
existing
intake
runs
the
length
of
the
intake.
This
configuration
provides
the
best
performance
from
an
operational
standpoint
because
it
allows
for
flow
balancing
between
the
screen/
pump
bays
and
the
individual
manifold
pipes.
If
there
are
no
concerns
with
obstructing
the
waterway,
the
sheet
pile
wall
can
be
placed
far
enough
out
so
that
the
portion
of
the
wall
parallel
to
the
intake
can
be
installed
first
along
with
the
pipes
and
screens
that
extend
further
offshore.
In
this
case,
the
plenum
ends
are
left
open
so
that
the
intake
can
remain
functional
until
the
offshore
construction
is
completed.
At
that
point,
the
intake
must
shut
down
to
install
the
final
end
portions
of
the
wall,
the
air
piping
connection
to
the
air
supply,
and
make
final
connections
of
the
manifold
pipes.
EPA
is
not
aware
of
any
existing
retrofits
where
this
construction
technique
has
been
used.
However,
it
has
been
proposed
in
a
feasibility
study
where
a
new,
larger
intake
was
to
be
constructed
offshore
(
see
discussion
in
Construction
Downtime
Section).

Costs
were
developed
for
this
module
based
on
the
second
scenario
described
above.
These
costs
are
assumed
equal
or
greater
than
costs
for
steel
plate(
s)
affixed
to
the
existing
intake
opening,
and
therefore
inclusive
of
either
approach.
This
assumption
is
based
on
the
use
of
a
greater
amount
of
steel
material
for
sheet
piles
(
which
is
offset
somewhat
by
the
fabrication
cost
for
the
steel
plates),
the
use
of
similarly­
sized
heavy
equipment
(
pile
driver
versus
crane),
and
similar
diver
costs
for
constructing
pipe
connections
and
reinforcements
in
the
sheet
pile
wall
versus
installing
plates.
Costs
were
developed
for
both
freshwater
environments
and,
with
the
inclusion
a
cost
factor
for
coating
the
steel
with
a
corrosion­
resistant
material,
for
saltwater
environments.

Connecting
Pipes
The
design
(
length
and
configuration)
of
the
connecting
pipes
(
also
referred
to
as
pipe
manifold
or
header)
is
partly
dictated
by
intake
flow
and
water
depth.
A
review
of
the
pipe
diameter
and
design
flow
data
submitted
to
EPA
by
facilities
with
submerged
offshore
intakes
indicates
intake
pipe
velocities
at
design
flow
were
typically
around
5
fps.
Note
that
a
minimum
of
2.5
to
3
fps
is
recommended
to
prevent
deposition
of
sediment
and
sand
in
the
pipe
(
Metcalf
&
Eddy
1972).
Also,
­
6­
calculations
based
on
vendor
data
concerning
screen
attachment
flange
size
and
design
flow
data
resulted
in
pipe
velocities
ranging
from
3.2
to
4.5
fps
for
the
nominal
size
pipe
connection.
EPA
has
elected
to
size
the
connecting
pipes
based
on
a
typical
design
pipe
velocity
of
5
fps.

Even
at
5
fps,
the
piping
requirements
are
substantial.
For
example,
if
the
existing
intake
has
traveling
screens
with
a
high
velocity
(
e.
g.,
2.5
fps
through­
screen
velocity),
then
the
cross­
sectional
area
of
the
intake
pipe
needed
to
provide
the
same
flow
would
be
approximately
one­
third
of
the
existing
screen
area
(
assuming
existing
screen
open
area
is
69%).
Given
the
above
assumptions,
an
existing
intake
with
a
10­
foot
wide
traveling
screen
and
a
20­
foot
water
depth
would
require
a
9.4­
foot
diameter
pipe
and
be
connected
to
at
least
four
8­
foot
diameter
T­
screens
(
T96).
The
flow
rate
for
this
hypothetical
intake
screen
would
be
155,000
gpm.

For
small
volume
flows
(
40,750
gpm
or
less
 
see
Table
1­
2),
T­
screens
(
particularly
those
with
a
single
screen
unit)
can
be
installed
very
close
to
the
existing
intake
structure,
as
the
upstream
or
downstream
extensions
of
the
screen
should
not
be
an
issue.
In
the
10­
foot
wide
by
20­
foot
deep
traveling
screen
example
above,
each
of
the
T96
screens
required
is
26
feet
long.
For
this
example,
it
is
possible
to
place
the
four
T96
screens
directly
in
front
of
the
existing
intake
connected
to
a
single
manifold
extending
56
feet
(
2*
8+
2*
8+
2*
8+
8)
to
the
centerline
of
the
last
T­
screen.
This
is
based
on
a
configuration
where
the
manifold
has
multiple
ports
(
four
in
this
case)
spaced
along
the
top.
However,
this
configuration
will
experience
some
flow
imbalance
between
the
screens.
A
better
configuration
would
be
a
single
pipe
branching
twice
in
a
double
"
H"
arrangement.
In
this
case,
the
total
pipe
length
would
be
62
feet
(
20+
26+
2*
8).
Therefore,
a
minimum
pipe
length
of
66
feet
(
20
meters)
was
selected
to
cover
the
pipe
installation
costs
for
screens
installed
close
to
the
intake.

Based
on
the
above
discussion,
facilities
with
design
flow
values
requiring
multiple
manifold
pipes
(
i.
e.,
>
163,000
gpm)
will
require
the
screens
to
extend
even
further
out.
In
these
cases,
costs
for
a
longer
pipe
size
are
appropriate.
Using
a
longer
pipe
allows
for
individual
screens
to
be
spread
out
laterally
and/
or
longitudinally.
Longer
pipes
would
also
tend
to
provide
access
to
deeper
water
where
larger
screens
can
be
used.
While
using
smaller
screens
allows
for
operations
in
shallower
water,
many
more
screens
would
be
needed.
This
configuration
covers
a
greater
bottom
area
and
requires
more
branching
and
longer,
but
smaller,
pipes.
Therefore,
with
the
exception
of
the
lower
intake
flow
facilities,
a
length
of
connecting
pipe
longer
than66
feet
(
20
meters)
is
assumed
to
be
required.

The
next
assumed
pipe
length
is
410
feet
(
125
meters),
based
on
the
PhaseI
proposed
rule
cost
estimates.
A
length
of
125
meters
was
selected
in
Phase
I
costing
as
a
reasonable
estimate
for
extending
intakes
beyond
the
littoral
zone.
Additional
lengths
of
820
feet
(
250
meters)
and
1640
feet
(
500
meters)
were
selected
to
cover
the
possible
range
of
intake
distances.
The
longest
distance
(
1640
feet)
is
similar
in
magnitude
to
the
intake
distances
reported
for
many
of
the
Phase
II
facilities
with
offshore
intakes
located
on
large
bodies
of
water,
such
as
oceans
and
Great
Lakes.

As
described
in
the
document
Economic
and
Engineering
Analyses
of
the
Proposed
Section
316(
b)
New
Facility
Rule,
Appendix
A,
submerged
intake
pipes
can
be
constructed
in
two
ways.
One
construction
uses
steel
that
is
concrete­
lined
and
coated
on
the
outside
with
epoxy
and
a
concrete
overcoat.
The
second
construction
uses
prestressed
concrete
cylinder
pipe
(
PCCP).
Steel
is
generally
used
for
lake
applications;
both
steel
and
PCCP
are
used
for
riverine
applications;
PCCP
­
7­
is
typically
used
in
ocean
applications.
A
review
of
the
submerged
pipe
laying
costs
developed
for
the
Phase
I
proposed
rule
showed
that
the
costs
of
installing
steel
and
PCCP
pipe
using
the
conventional
method
were
similar,
with
steel
being
somewhat
higher
in
cost.
EPA
has
thus
elected
to
use
the
Phase
I
cost
methodology
for
conventional
steel
pipe
as
representative
of
the
cost
for
both
steel
and
concrete
pipes
installed
in
all
waterbodies.
The
conventional
pipe
laying
method
was
selected
because
it
could
be
performed
in
front
of
an
existing
intake
and
was
least
affected
by
the
limitations
associated
with
local
topography.

While
other
methods
such
as
the
bottom­
pull
or
micro­
tunneling
methods
could
potentially
be
used,
the
bottom­
pull
method
requires
sufficient
space
for
laying
pipe
onshore
while
the
micro­
tunneling
method
requires
that
a
shaft
be
drilled
near
the
shoreline,
which
may
be
difficult
to
perform
in
conjunction
with
an
existing
intake.
The
conventional
steel
pipe
laying
cost
methodology
and
assumptions
are
described
in
detail
in
the
document
Economic
and
Engineering
Analyses
of
the
Proposed
Section
316(
b)
New
Facility
Rule,
Appendix
A.

1.1.2
Capital
Cost
Development
Screen
Material
Construction
and
Costs
Costs
were
obtained
for
T­
screens
constructed
of
three
different
types
of
materials:
304
stainless
steel,
316
stainless
steel,
and
copper­
nickel
(
CuNi)
alloy.
In
general,
screens
installed
in
freshwater
are
constructed
of
304
stainless
steel.
However,
where
Zebra
Mussels
are
a
problem,
CuNi
alloys
are
often
used
because
the
leached
copper
tends
to
discourage
screen
biofouling
with
Zebra
mussels.
In
corrosive
environments
such
as
brackish
and
saltwater,
316
stainless
steel
is
often
used.
If
the
corrosive
environment
is
harsh,
particularly
where
oxygen
levels
are
low,
CuNi
alloys
are
recommended.
Since
the
T­
screens
are
to
be
placed
extending
out
into
the
waterway,
such
low
oxygen
environments
are
not
expected
to
be
encountered
very
often.

Based
on
this
information,
EPA
has
chosen
to
base
the
cost
estimates
on
utilizing
screens
made
of
304
stainless
steel
for
freshwater
environments
without
Zebra
Mussels,
CuNi
alloy
for
freshwater
environments
with
the
potential
for
Zebra
Mussels
and
316
stainless
steel
for
brackish
and
saltwater
environments.
Table
1­
3
provides
a
list
of
states
that
contain
or
are
adjacent
to
waterbodies
where
Zebra
Mussels
are
currently
found.
The
cost
for
CuNi
screens
are
applied
to
all
freshwater
environments
located
within
these
states.
EPA
notes
that
the
screens
comprise
only
a
small
portion
of
the
total
costs,
particularly
where
the
design
of
other
components
are
the
same,
such
as
the
proposed
design
scenarios
for
freshwater
environments
with
Zebra
Mussels
versus
those
without.
­
8­
State
Name
Abbreviation
Alabama
AL
Connecticut
CT
Illinois
IL
Indiana
IN
Iowa
IA
Kentucky
KY
Louisiana
LA
Michigan
MI
Minnesota
MN
Mississippi
MS
Missouri
MO
New
York
NY
Ohio
OH
Oklahoma
OK
Pennsylvania
PA
Tennessee
TN
Vermont
VT
West
Virginia
WV
Wisconsin
WI
List
of
States
with
Freshwater
Zebra
Mussels
as
of
2001
TABLE
1­
3
Table
1­
4
presents
the
component
and
total
installed
costs
for
the
three
types
of
screens.
Installation
and
mobilization
costs
are
based
on
vendor­
provided
cost
estimates
for
velocity
caps,
which
are
comparable
to
those
for
T­
screens.
The
individual
installation
cost
per
screen
of
$
35,000
was
reduced
by
30%
for
multiple
screen
installations.
Costs
for
steel
fittings
are
also
included.
These
costs
are
based
on
steel
fitting
costs
developed
for
Phase
I
and
are
adjusted
for
a
pipe
velocity
of
5
fps
and
converted
to
2002
dollars.
An
additional
5%
was
added
to
the
total
installed
screen
costs
to
account
for
installation
of
intake
protection
and
warning
devices
such
as
pilings,
dolphins,
buoys,
and
warning
signs.
1
Note
that
this
50%
value
was
derived
by
comparing
the
estimated
costs
of
a
sheet
pile
wall
presented
in
a
feasibility
study
for
the
Salem
Nuclear
Plant
to
the
cost
estimated
for
a
similarly
sized
sheet
pile
wall
using
the
EPA
method
described
here.
This
factor
was
intended
to
cover
the
cost
of
items
such
as
walers,
bracing
and
installation
costs
not
included
in
the
Costworks
unit
cost.
The
Salem
facility
costs
included
bypass
gates,
which
are
assumed
to
be
similar
in
cost
to
the
pipe
connections.

­
9­
SIZE
NUMBER
OF
SCREENS
CAPACITY
AIR
BURST
EQUIPMENT
SCREEN
INSTALL
ATION
MOBILIZAT
ION
STEEL
FITTING
GPM
304SS
316SS
CuNi
304SS
316SS
CuNi
T24
1
2,500
$
5,800
$
6,100
$
8,000
$
10,450
$
25,000
$
15,000
$
2,624
$
50,846
$
51,161
$
53,156
T36
1
5,700
$
10,000
$
11,200
$
18,000
$
15,050
$
25,000
$
15,000
$
3,666
$
56,349
$
57,609
$
64,749
T48
1
10,000
$
17,000
$
18,800
$
31,700
$
22,362
$
30,000
$
15,000
$
5,067
$
70,421
$
72,311
$
85,856
T60
1
15,800
$
23,000
$
26,200
$
44,500
$
28,112
$
35,000
$
15,000
$
6,964
$
83,962
$
87,322
$
106,537
T72
1
22,700
$
34,000
$
39,500
$
69,700
$
35,708
$
35,000
$
20,000
$
9,227
$
103,139
$
108,914
$
140,624
T84
1
31,000
$
45,000
$
51,900
$
93,400
$
43,588
$
35,000
$
20,000
$
11,961
$
117,560
$
124,805
$
168,380
T96
1
40,750
$
61,000
$
70,200
$
124,000
$
49,338
$
35,000
$
25,000
$
15,189
$
142,999
$
152,659
$
209,149
T96
2
81,500
$
122,000
$
140,400
$
248,000
$
49,338
$
49,000
$
25,000
$
28,865
$
236,108
$
255,428
$
368,408
T96
3
122,250
$
183,000
$
210,600
$
372,000
$
49,338
$
73,500
$
30,000
$
42,840
$
345,807
$
374,787
$
544,257
T96
4
163,000
$
244,000
$
280,800
$
496,000
$
49,338
$
98,000
$
30,000
$
57,113
$
450,569
$
489,209
$
715,169
MATERIAL
TOTAL
INSTALLED
SCREEN
COSTS
EXCLUDING
AIRBURST
SYSTEM
TABLE
1­
4
T­
SCREEN
EQUIPMENT
AND
INSTALLATION
COSTS
Connecting
Wall
Cost
Development
The
cost
for
the
connecting
wall
that
blocks
off
the
existing
intake
and
provides
the
connection
to
the
screen
pipes
is
based
on
the
cost
of
an
interlocking
sheet
pile
wall
constructed
directly
in
front
of
the
existing
intake.
In
general,
the
costs
are
mostly
a
function
of
the
total
area
of
the
wall
and
will
vary
some
with
depth.
Cost
estimates
were
developed
for
a
range
of
wall
dimensions.
The
first
step
was
to
estimate
the
nominal
length
of
the
existing
intake
for
each
of
the
design
flow
values
shown
in
Table
1­
1.
The
nominal
length
was
estimated
using
an
assumed
water
depth
and
intake
velocity.
The
use
of
actual
depths
and
intake
velocities
imparted
too
many
variables
for
the
selected
costing
methodology.
A
depth
of
20
feet
was
selected
because
it
was
close
to
both
the
mean
and
median
intake
water
depth
values
reported
by
Phase
II
facilities
in
their
Detailed
Technical
Questionnaires.

The
length
of
the
wall
was
also
based
on
an
assumed
existing
intake,
through­
screen
velocity
of
1
fps
and
an
existing
screen
open
area
of
50%.
Most
existing
coarse
screens
have
an
open
area
of
69%.
However,
a
50%
area
was
chosen
to
produce
a
larger
(
i.
e.,
more
costly)
wall
size.
Selecting
a
screen
velocity
of
1
fps
also
will
overestimate
wall
length
(
and
therefore,
costs)
for
existing
screen
velocities
greater
than
1
fps.
This
is
the
case
for
most
of
the
facilities
(
just
under
70%
of
the
Phase
II
Facilities
reported
screen
velocities
of
1
fps
or
greater).
An
additional
length
of
30
to
60
feet
(
scaled
between
30
feet
for
3150
gpm
to
60
feet
for
182,44
gpm)
was
added
to
cover
the
end
portions
of
the
wall
and
to
cover
fixed
costs
for
smaller
intakes.
The
costs
are
based
on
the
following:

°
Sheet
pile
unit
cost
of
$
24.50/
sq
ft
(
Costworks
2001)
°
An
additional
50%
of
sheet
pile
cost
to
cover
costs
not
included
in
sheet
pile
unit
cost1
°
Total
pile
length
of
45
feet
for
20­
foot
depth
including
15­
foot
penetration
and
10­
foot
extension
above
water
level
­
10­
Design
Flow
Total
Estimated
Wall
Length
Mobilization
gpm
Ft
Freshwater
Saltwater
2,500
31
$
36,600
$
87,157
$
103,840
5,700
32
$
36,600
$
89,351
$
106,758
10,000
34
$
36,600
$
92,359
$
110,759
15,800
36
$
36,600
$
96,416
$
116,155
22,700
39
$
36,600
$
101,243
$
122,575
31,000
43
$
36,600
$
107,049
$
130,297
40,750
47
$
36,600
$
113,870
$
139,369
81,500
64
$
36,600
$
142,376
$
177,283
122,250
81
$
36,600
$
170,883
$
215,196
163,000
96
$
36,600
$
195,960
$
248,549
Sheet
Pile
Wall
Costs
20
Ft
Water
Depth
SHEET
PILE
WALL
CAPITAL
COSTS
°
Mobilization
of
$
18,300
for
20­
foot
depth
(
Costworks
2001),
added
twice
(
assuming
sheet
pile
would
be
installed
in
two
stages
to
minimize
generating
unit
downtime
(
see
Downtime
discussion)
°
An
additional
cost
of
33%
for
corrosion­
resistant
coating
for
saltwater
environments.

Table
1­
5
presents
the
estimated
wall
lengths,
mobilization
costs,
and
total
costs
for
20­
foot
depth
for
both
freshwater
and
saltwater
environments.

TABLE
1­
5
Pipe
Manifold
Cost
Development
For
facilities
with
design
intake
flows
that
are
10%
or
more
greater
than
163,000
gpm
(
i.
e.,
above
180,000
gpm),
multiple
intakes
are
costed
and
the
costs
summed.
This
apoproach
leads
to
probable
costing
over­
estimates
for
both
the
added
length
of
end
sections
wall
costs.

Pipe
costs
are
developed
using
the
same
general
methodology
as
described
in
Economic
and
Engineering
Analyses
of
the
Proposed
Section
316(
b)
New
Facility
Rule,
Appendix
A,
but
modified
based
on
a
design
pipe
velocity
of
5
fps.
The
pipe
laying
cost
methodology
was
revised
to
include:
costs
for
several
different
pipe
lengths
were
developed.
These
pipe
lengths
include:
66
feet
(
20
meters),
410
feet
(
125
meters),
820
feet
(
250
meters),
and
1640
feet
(
500
meters).
The
cost
for
pipe
installation
includes
an
equipment
rental
component
for
the
pipe
laying
vessel,
support
barge,
crew,
and
pipe
laying
equipment.
The
Phase
I
proposed
rule
Economic
and
Engineering
Analyses
document
estimates
that
500
feet
of
pipe
can
be
laid
in
a
day
under
favorable
conditions.
Equipment
rental
costs
for
the
longer
piping
distances
were
adjusted
upward,
in
single­
day
increments,
to
limit
daily
production
rates
not
to
exceed
550
feet/
day.
For
the
shorter
distance
of
66
feet
(
20
meters),
the
single­
day
pipe
laying
vessel/
equipment
costs
were
reduced
by
a
factor
of
40%.
This
reduction
is
­
11­
based
on
the
assumption
that,
in
most
cases,
a
pipe
laying
vessel
is
not
needed
because
installation
can
be
performed
via
crane
located
on
the
shoreline.

Figure
1­
1
presents
the
capital
cost
curves
for
the
pipe
portion
only
for
each
of
the
offshore
distance
scenarios.
The
pipe
cost
development
methodology
adopted
from
the
Phase
I
effort
used
a
different
set
of
flow
values
than
are
shown
in
Table
1­
1.
Therefore,
second­
order,
best­
fit
equations
were
derived
from
pipe
cost
data.
These
equations
were
applied
to
the
flow
values
in
Table
1­
1
to
obtain
the
relevant
installed
pipe
cost
component.

An
additional
equipment
component
representing
the
cost
of
pipe
fittings
such
as
tees
or
elbows
are
also
included.
The
costs
are
based
on
the
cost
estimates
developed
for
the
Phase
I
proposed
rule,
adjusted
to
a
pipe
velocity
of
5
fps
and
2002
dollars.

Airburst
System
Costs
Capital
costs
for
airburst
equipment
sized
to
backwash
each
of
the
T­
screens
were
obtained
from
vendor
estimates.
These
costs
included
air
supply
equipment
(
compressor,
accumulator,
distributor)
minus
the
piping
to
the
screens,
air
supply
housing,
and
utility
connections
and
wiring.
Capital
costs
of
the
airburst
air
supply
system
are
shown
in
Table
1­
6.
Costs
for
a
housing
structure,
electrical,
and
controls
were
added
based
on
the
following:

°
electrical
costs
=
10%
of
air
supply
equipment
(
BPJ)
°
Controls
=
5%
of
air
supply
equipment
(
BPJ)
°
Housing
=
$
142/
sq
ft
for
area
shown
in
Table
1­
6.
This
cost
was
based
on
the
$
130/
sq
ft
cost
used
in
the
Phase
I
cost
for
pump
housing,
adjusted
to
2002
dollars.
­
12­
Screen
Size
Vendor
Supplied
Equipment
Costs
Estimated
Housing
Area
Housing
Area
Housing
Costs
Electrical
Controls
Total
Airburst
Minus
Air
Piping
to
Screens
sq
ft
10%
5%
T24
$
6,000
5x5
25
$
3,550
$
600
$
300
$
10,450
T36
$
10,000
5x5
25
$
3,550
$
1,000
$
500
$
15,050
T48
$
15,000
6x6
36
$
5,112
$
1,500
$
750
$
22,362
T60
$
20,000
6x6
36
$
5,112
$
2,000
$
1,000
$
28,112
T72
$
25,000
7x7
49
$
6,958
$
2,500
$
1,250
$
35,708
T84
$
30,000
8x8
64
$
9,088
$
3,000
$
1,500
$
43,588
T96
$
35,000
8x8
64
$
9,088
$
3,500
$
1,750
$
49,338
TABLE
1­
6
CAPITAL
COSTS
OF
AIRBURST
AIR
SUPPLY
EQUIPMENT
The
costs
of
the
air
supply
pipes,
or
"
blow
pipes,"
are
calculated
for
each
installation
depending
on
the
length
of
the
intake
pipe,
plus
an
assumed
average
distance
of
70
feet
from
the
airburst
system
housing
to
the
intake
pipe
at
the
front
of
the
sheet
pile
wall.
Pipe
costs
are
based
on
this
total
distance
multiplied
by
a
derived
unit
cost
of
installed
pipe
Vendors
indicated
that
the
pipes
are
typically
made
of
schedule
10
stainless
steel
or
high
density
polyethylene
and
that
material
costs
are
only
a
portion
of
the
total
installed
costs.
Consistent
with
the
selection
of
screen
materials,
EPA
chose
to
assume
that
the
blow
pipes
are
constructed
of
304
stainless
steel
for
freshwater
and
316
stainless
steel
for
saltwater
applications.

The
unit
costs
for
the
installed
blow
pipes
are
based
on
the
installed
cost
of
similar
pipe
in
a
structure
on
land
multiplied
by
an
underwater
installation
factor.
This
underwater
installation
factor
was
derived
by
reviewing
the
materials­
versus­
total
costs
for
underwater
steel
pipe
installation,
which
ranged
from
about
3.2
to
4.5
with
values
decreasing
with
increasing
pipe
size.
A
review
of
the
materials­
versus­
installed­
on­
land
costs
for
the
smaller
diameter
stainless
steel
pipe
(
Costworks
2001)
found
that
if
the
installed­
on­
land
unit
costs
are
multiplied
by
2.0,
the
resulting
materials­
to­
totalestimated
(
underwater)­
installed­
cost
ratios
fell
within
a
similar
range.
These
costs
are
considered
as
over­
estimating
costs
somewhat
because
they
include
304
and
316
stainless
steel
where
less
costly
materials
may
be
used.
Also,
they
do
not
consider
potential
savings
associated
with
concurrent
installation
alongside
the
much
larger
water
intake
pipe.

Blow
pipe
sizes
were
provided
by
vendors
for
T60
and
smaller
screens.
For
larger
screens,
the
blow
pipe
diameter
was
derived
by
calculating
pipe
diameters
(
and
rounding
up
to
even
pipe
sizes)
using
the
same
ratio
of
screen
area
to
blow
pipe
area
calculated
for
T60
screens.
This
is
based
on
the
assumption
that
blow
pipe
air
velocities
are
proportional
to
the
needed
air/
water
backwash
velocities
at
the
screen
surface.
A
separate
blow
pipe
was
included
for
each
T­
screen
where
multiple
screens
are
included,
but
only
one
set
of
the
air
supply
equipment
(
compressor,
accumulator,
distributor,
­
13­
Design
Flow
Air
Pipe
Unit
Cost
­
Schedule
10
304
SS
Air
Pipe
Unit
Cost
­
Schedule
10
316
SS
gpm
$/
Ft
$/
Ft
20
Meters
125
Meters
250
Meters
500
Meters
20
Meters
125
Meters
250
Meters
500
Meters
2,500
$
55.0
$
62.0
$
7,458
$
26,400
$
48,950
$
94,050
$
8,407
$
29,760
$
55,180
$
106,020
5,700
$
82.0
$
98.0
$
11,119
$
39,360
$
72,980
$
140,220
$
13,289
$
47,040
$
87,220
$
167,580
10,000
$
98.0
$
114.0
$
13,289
$
47,040
$
87,220
$
167,580
$
15,458
$
54,720
$
101,460
$
194,940
15,800
$
154.0
$
181.0
$
20,882
$
73,920
$
137,060
$
263,340
$
24,544
$
86,880
$
161,090
$
309,510
22,700
$
214.0
$
268.0
$
29,018
$
102,720
$
190,460
$
365,940
$
36,341
$
128,640
$
238,520
$
458,280
31,000
$
292.0
$
354.0
$
39,595
$
140,160
$
259,880
$
499,320
$
48,002
$
169,920
$
315,060
$
605,340
40,750
$
362.0
$
438.0
$
49,087
$
173,760
$
322,180
$
619,020
$
59,393
$
210,240
$
389,820
$
748,980
81,500
$
362.0
$
438.0
$
98,174
$
347,520
$
644,360
$
1,238,040
$
118,786
$
420,480
$
779,640
$
1,497,960
122,250
$
362.0
$
438.0
$
147,262
$
521,280
$
966,540
$
1,857,060
$
178,178
$
630,720
$
1,169,460
$
2,246,940
163,000
$
362.0
$
438.0
$
196,349
$
695,040
$
1,288,720
$
2,476,080
$
237,571
$
840,960
$
1,559,280
$
2,995,920
Saltwater
Airburst
Distribution
Installed
Pipe
Costs
Freshwater
Airburst
Distribution
Installed
Pipe
Costs
controls
etc.)
is
included
in
each
installation.
The
calculated
costs
for
the
air
supply
pipes
are
shown
in
Table
1­
7.

TABLE
1­
7
CAPITAL
COSTS
OF
INSTALLED
AIR
SUPPLY
PIPES
Indirect
Costs
The
total
calculated
capital
costs
were
adjusted
to
include
the
following
added
costs:

°
Engineering
at
10%
of
direct
capital
costs
°
Contractor
overhead
and
profit
at
15%
of
direct
capital
costs
(
based
on
O&
P
component
of
installing
lift
station
in
Costworks
2001);
some
direct
cost
components,
e.
g.,
the
intake
pipe
cost
and
blow
pipe
cost,
already
include
costs
for
contractor
overhead
and
profit
°
Contingency
at
10%
of
direct
capital
costs
°
Sitework
at
10%
of
direct
capital
costs;
based
on
sitework
component
of
Fairfax
Water
Intake
costs
data,
including
costs
for
erosion
&
sediment
control,
trash
removal,
security,
dust
control,
access
road
improvements,
and
restoration
(
trees,
shrubs,
seeding
&
sodding).

Total
Capital
Costs
Table
1­
8
presents
the
total
capital
costs
of
the
complete
system
including
indirect
costs.
Figures
1­
2,
1­
3,
and
1­
4
present
the
plotted
capital
costs
in
Table
1­
8
for
freshwater,
saltwater,
and
freshwater
with
Zebra
mussels,
respectively.
Figures
1­
2,
1­
3,
and
1­
4
also
present
the
best­
fit,
second
order
equations
used
in
estimating
compliance
costs.
­
14­

Design
Flow
gpm
304
SS
316
SS
CuNi
304
SS
316
SS
CuNi
304
SS
316
SS
CuNi
304
SS
316
SS
CuNi
Freshwater
Saltwater
Zebra
Mussels
Freshwater
Saltwater
Zebra
Mussels
Freshwater
Saltwater
Zebra
Mussels
Freshwater
Saltwater
Zebra
Mussels
3,150
$
226,234
$
244,261
$
228,544
$
317,824
$
338,262
$
320,134
$
484,935
$
508,243
$
487,245
$
708,887
$
737,935
$
711,197
7,100
$
246,433
$
267,593
$
254,833
$
368,265
$
394,936
$
376,665
$
571,913
$
605,144
$
580,313
$
868,212
$
914,563
$
876,612
11,400
$
276,666
$
299,449
$
292,101
$
426,879
$
455,173
$
442,314
$
664,952
$
699,805
$
680,387
$
1,029,380
$
1,077,354
$
1,044,815
17,800
$
313,965
$
341,187
$
336,540
$
517,642
$
554,163
$
540,217
$
820,421
$
868,012
$
842,996
$
1,313,330
$
1,383,061
$
1,335,905
25,650
$
362,161
$
397,272
$
399,646
$
628,646
$
682,354
$
666,131
$
1,007,678
$
1,083,526
$
1,045,163
$
1,652,171
$
1,772,299
$
1,689,656
34,950
$
411,364
$
451,176
$
462,184
$
754,958
$
816,123
$
805,778
$
1,227,803
$
1,314,388
$
1,278,623
$
2,059,145
$
2,196,571
$
2,109,965
45,600
$
471,488
$
518,072
$
537,638
$
897,156
$
969,915
$
963,306
$
1,470,358
$
1,574,277
$
1,536,508
$
2,501,955
$
2,668,193
$
2,568,105
91,200
$
707,345
$
784,421
$
839,645
$
1,511,007
$
1,640,433
$
1,643,307
$
2,549,704
$
2,741,450
$
2,682,004
$
4,515,446
$
4,831,832
$
4,647,746
136,800
$
976,111
$
1,083,680
$
1,174,561
$
2,166,086
$
2,352,178
$
2,364,536
$
3,686,913
$
3,966,485
$
3,885,363
$
6,628,388
$
7,094,920
$
6,826,838
182,400
$
1,246,414
$
1,381,225
$
1,511,014
$
2,831,017
$
3,070,526
$
3,095,617
$
4,850,609
$
5,214,758
$
5,115,209
$
8,809,404
$
9,422,833
$
9,074,004
Total
Costs
500
Meters
Offshore
Total
Costs
20
Meters
Offshore
Total
Costs
125
Meters
Offshore
Total
Costs
250
Meters
Offshore
TABLE
1­
8
TOTAL
CAPITAL
COSTS
OF
INSTALLED
T­
SCREEN
SYSTEM
AT
EXISTING
SHORELINE
BASED
INTAKES
­
15­
Nuclear
Facilities
Construction
and
material
costs
tend
to
be
substantially
greater
for
nuclear
facilities
due
to
burden
of
increased
security
and
to
the
requirements
for
more
robust
system
design.
Rather
than
performing
a
detailed
evaluation
of
the
differences
in
capital
costs
for
nuclear
facilities,
EPA
has
chosen
to
apply
a
simple
cost
factor
based
on
total
costs.

In
the
Phase
I
costing
effort,
EPA
used
data
from
an
Argonne
National
Lab
study
on
retrofitting
costs
of
fossil
fuel
power
plants
and
nuclear
power
plants.
This
study
reported
average,
comparative
costs
of
$
171
for
nuclear
facilities
and
$
108
for
fossil
fuel
facilities,
resulting
in
a
1.58
costing
factor.
In
comparison,
recent
consultation
with
a
traveling
screen
vendor,
the
vendor
indicated
costing
factors
in
the
range
of
1.5­
2.0
were
reasonable
for
estimating
the
increase
in
costs
associated
with
nuclear
power
plants
based
on
their
experience.
Because
there
are
likely
to
be
additional
security
burdens
above
that
experienced
when
the
Argonne
Report
was
generated,
EPA
has
selected
1.8
as
a
capital
costing
factor
for
nuclear
facilities.
Costs
for
nuclear
facilities
are
not
presented
here
but
can
be
estimated
by
multiplying
the
applicable
non­
nuclear
facility
costs
by
the
1.8
costing
factor.

O&
M
Costs
O&
M
cost
are
based
on
the
sum
of
costs
for
annual
inspection
and
cleaning
of
the
intake
screens
by
a
dive
team
and
for
estimated
operating
costs
for
the
airburst
air
supply
system.
Dive
team
costs
were
estimated
for
a
total
job
duration
of
one
to
four
days,
and
are
shown
in
Table
1­
9.
Dive
team
cleaning
and
inspections
were
costed
at
once
per
year
for
low
debris
locations
and
twice
per
year
for
high
debris
locations.
The
O&
M
costs
for
the
airburst
system
are
based
on
power
requirements
of
the
air
compressor
and
labor
requirements
for
routine
O&
M.
Vendors
cited
a
backwash
frequency
per
screen
from
as
low
as
once
per
week
to
as
high
as
once
per
hour.
The
time
needed
to
recharge
the
accumulator
is
about
0.5
hours,
but
can
be
as
high
as
1
hour
for
those
with
smaller
compressors
or
accumulators
that
backwash
more
than
one
screen
simultaneously.

The
Hp
rating
of
the
typical
size
airburst
compressor
for
each
screen
size
was
obtained
from
a
vendor
and
is
presented
in
the
table
in
Attachment
A.
A
vendor
stated
that
several
hours
per
week
would
be
more
than
enough
labor
for
routine
maintenance,
so
labor
is
assumed
to
be
two
to
four
hours
per
week
based
on
roughly
half­
hour
daily
inspection
of
the
airburst
system.
However,
during
seasonal
periods
of
high
debris
such
as
leaves
in
the
fall,
it
may
be
necessary
for
someone
to
man
the
backwash
system
24
hours/
day
for
several
weeks
(
Frey
2002).
Thus,
an
additional
two
to
four
weeks
of
24­
hour
labor
are
included
for
these
periods
(
two
weeks
low
debris;
four
weeks
high
debris).

The
O&
M
cost
of
the
airburst
system
are
based
on
the
following:

°
Average
backwash
frequency
in
low
debris
areas
is
2
times
per
day
°
Average
backwash
frequency
in
high
debris
areas
is
12
times
per
day
°
Time
to
recharge
accumulator
is
0.5
hours
°
Compressor
motor
efficiency
is
90%
°
Cost
of
electric
power
consumed
is
$
0.04/
Kwh
°
Routine
inspection
and
maintenance
labor
is
3
hours
per
week
for
systems
up
to
182,400
gpm
­
16­
Item
Daily
Cost*
One
Time
Cost*
Total
Duration
One
Day
One
Day
Two
Day
Three
Day
Four
Day
Cost
Year
1999
2002
2002
2002
2002
Supervisor
$
575
$
575
$
627
$
1,254
$
1,880
$
2,507
Tender
$
200
$
200
$
218
$
436
$
654
$
872
Diver
$
375
$
750
$
818
$
1,635
$
2,453
$
3,270
Air
Packs
$
100
$
100
$
109
$
218
$
327
$
436
Boat
$
200
$
200
$
218
$
436
$
654
$
872
Mob/
Demob
$
3,000
$
3,000
$
3,270
$
3,270
$
3,270
$
3,270
Total
$
4,825
$
5,260
$
7,250
$
9,240
$
11,230
*
Source:
Paroby
1999
(
cost
adjusted
to
2002
dollars).
Adjusted
Total
Installation
and
Maintenance
Diver
Team
Costs
°
O&
M
labor
rate
per
hour
is
$
38.00/
hr.
The
rate
is
based
on
Bureau
of
Labor
Statistics
Data
using
the
median
labor
rates
for
electrical
equipment
maintenance
technical
labor
(
SOC
49­
2095)
and
managerial
labor
(
SOC
11­
1021);
benefits
and
other
compensation
are
added
using
factors
based
on
SIC
29
data
for
blue
collar
and
white
collar
labor.
The
two
values
were
combined
into
a
single
rate
assuming
90%
technical
labor
and
10%
managerial.
See
Doley
2002
for
details.

TABLE
1­
9
ESTIMATED
COSTS
FOR
DIVE
TEAM
TO
INSPECT
AND
CLEAN
T­
SCREENS
Attachment
A
presents
the
worksheet
data
used
to
develop
the
annual
O&
M
costs,
plotted
in
Figure
1­
5.
Figure
1­
5
also
shows
the
second­
order
equations
that
were
fitted
to
these
data
and
used
to
estimate
the
O&
M
costs
for
individual
Phase
II
facilities.
As
with
the
capital
costs,
at
facilities
where
the
design
flow
exceeds
the
maximum
cost
model
design
flow
of
163,000
gpm
plus
10%
(
180,000
gpm),
the
design
flow
are
divided
and
the
corresponding
costs
are
summed.

Construction
Related
Downtime
Downtime
may
be
a
substantial
cost
item
for
retrofits
using
the
existing
pump
wells
and
pumps.
The
proposed
EPA
retrofit
scenario
includes
a
sheet
pile
wall
in
front
of
the
existing
intake.
This
scenario
is
modeled
after
a
proposed
scenario
presented
in
a
feasibility
study
for
the
Salem
Nuclear
Plant.
In
this
scenario,
a
sheet
pile
plenum
with
bypass
gates
is
constructed
40
feet
in
front
of
the
existing
intake
with
about
twelve
10­
foot
diameter
header
pipes
connecting
the
plenum
to
about
240
T­
screens.
Construction
is
estimated
to
take
two
years,
with
installation
of
the
sheet
pile
plenum
in
the
first
year.
The
facility
projects
the
installation
of
10­
foot
header
pipes
and
screens
to
take
nine
months
and
the
air
backwash
piping
to
take
two
months.
The
feasibility
study
states
that
Units
1
&
2
would
each
have
to
be
shutdown
for
about
six
months,
to
install
the
plenum,
and
for
an
additional
two
months
to
install
the
10­
foot
header
pipe
connection
to
the
plenum
and
to
install
the
air
piping.
Thus,
an
estimated
total
of
eight
months
downtime
is
estimated
for
this
very
large
(
near
worst
case)
­
17­
intake
scenario.
This
scenario
was
discarded
by
the
facility
due
to
uncertainty
about
biofouling
and
debris
removal
at
slack
tides.
No
cost
estimates
were
developed
and,
therefore
no
incentive
to
focus
on
a
system
design
and
a
construction
sequence
that
would
minimize
downtime
existed.

In
the
same
feasibility
study,
a
scenario
is
proposed
where
a
new
intake
with
dual
flow
traveling
screens
is
installed
at
a
distance
of
65
feet
offshore
inside
a
cofferdam.
In
this
scenario,
a
sheet
pile
plenum
wall
connects
the
new
intake
to
the
existing
shore
intake.
In
this
scenario
the
intake
is
constructed
first;
Units
1
&
2
are
estimated
to
be
shut
down
for
about
one
month
each
to
construct
and
connect
the
plenum
walls
to
the
existing
intake.

It
would
seem
that
the
T­
screen
plenum
construction
scenario
could
follow
the
same
approach,
i.
e.,
performed
while
the
units
are
operating.
This
apporach
would
result
in
a
much
lower
downtime,
similar
to
that
for
the
offshore
intake,
but
including
consideration
for
added
time
for
near­
shore
air
pipe
installation.
There
are
two
relevant
differences
between
these
scenarios.
One
is
the
distance
offshore
to
the
T­
screen
piping
connection
versus
the
new
intake
structure
(
40
feet
versus
65
feet).
The
second
is
that
T­
screens,
pipes,
and
plenum
would
be
installed
underwater
while
the
new
intake
would
be
constructed
behind
a
coffer
dam.
Conceivably
the
offshore
portion
of
the
T­
screen
plenum
(
excluding
the
ends)
and
all
pipe
and
screen
installation
on
the
offshore
side
could
be
performed
without
shutting
down
the
intake.

The
WH
Zimmer
plant
is
one
of
the
few
facilities
that
EPA
has
identified
as
actually
having
converted
an
existing
shoreline
intake
with
traveling
screens
to
submerged
offshore
T­
screens.
This
facility
was
originally
constructed
as
a
nuclear
facility
but
was
never
completed.
In
the
late
80'
s
it
was
converted
to
a
coal
fired
plant.
The
original
intake
was
to
supply
service
water
and
make­
up
water
for
recirculating
wet
towers,
and
had
been
completed.
However,
the
area
in
front
of
the
intake
was
plagued
with
sediment
deposition.
A
decision
was
made
to
abandon
the
traveling
screens
and
install
T­
screens
approximately
50
feet
offshore.
However,
because
the
facility
was
not
operating
at
the
time
of
this
conversion,
there
was
no
monetary
incentive
to
minimize
construction
time.
Actual
construction
took
six
to
eight
months
for
this
intake,
with
a
design
flow
of
about
61,000
gpm
(
Frey
2002).
The
construction
method
in
this
case
used
a
steel
wall
installed
in
front
of
the
existing
intake
pump
wells.

The
WH
Zimmer
plant
engineer
was
consulted
and
asked
to
estimate
how
long
it
would
take
to
perform
this
retrofit
particularly
with
a
goal
of
minimizing
generating
unit
downtime.
The
estimated
downtime
was
a
minimum
of
seven
to
nine
weeks,
assuming
mobilization
goes
smoothly
and
a
tight
construction
schedule
is
maintained.
A
more
generous
estimate
of
a
total
of
12
to
15
weeks
was
estimated
for
their
facility.
This
estimate
includes
five
to
six
weeks
for
installing
piping
(
some
support
pilings
can
be
laid
ahead
of
time),
an
additional
five
to
six
weeks
to
tie
in
piping
and
install
the
wall,
and
an
additional
two
to
three
weeks
to
clean
and
dredge
the
intake
area.
This
last
two­
to
three­
week
period
was
a
construction
step
somewhat
unique
to
the
Zimmer
plant,
especially
because
the
presence
of
sediment
was
the
driving
factor
in
the
decision
to
convert
the
system.

Based
on
the
above
information,
EPA
has
concluded
that
a
reasonable
unit
downtime
should
be
in
the
range
of
8
to
12
weeks.
It
is
reasonable
to
assume
that
this
downtime
can
be
scheduled
to
coincide
with
routine
generating
unit
downtime
of
approximately
four
weeks
or
longer,
resulting
in
a
total
­
18­
potential
lost
generation
period
of
four
to
eight
weeks.
Rather
than
select
a
single
downtime
for
all
facilities
installing
passive
screens,
EPA
chose
to
apply
the
8
to
12
week
downtime
duration
based
on
variations
in
project
size
using
design
flow
as
a
measure
of
size.
As
such,
EPA
assumed
a
downtime
of
8
weeks
for
facilities
with
intake
flow
volumes
of
less
than
400,000
gpm,
10
weeks
for
facilities
with
intake
flow
volumes
greater
than
400,000
gpm
but
less
than
800,000
gpm,
and
12
weeks
for
facilities
with
intake
flow
volumes
greater
than
800,000
gpm.

Application
General
Applicability
The
following
site­
related
conditions
may
preclude
the
use
of
passive
T­
screens
or
create
operational
problems:

°
Water
depths
of
<
2
feet
at
screen
location;
for
existing
facilities
this
should
not
be
an
issue
°
Stagnant
waterbodies
with
high
debris
load
°
Waterbodies
with
frazil
ice
in
winter.

Frazil
ice
consists
of
fine,
small,
needle­
like
structures
or
thin,
flat,
circular
plates
of
ice
suspended
in
water.
In
rivers
and
lakes
it
is
formed
in
supercooled,
turbulent
water.
Remedies
for
this
problem
include
finding
another
location
such
as
deeper
water
that
is
outside
of
the
turbulent
water
or
creating
a
provision
for
periodically
applying
heated
water
to
the
screens.
The
application
of
heated
water
may
not
be
feasible
or
economically
justifiable
in
many
instances.

Some
facilities
have
reported
limited
success
in
alleviating
frazil
ice
problems
by
blowing
a
small
constant
stream
of
air
through
the
screen
backwash
system
(
Whitaker
2002b).

Application
of
Different
Pipe
Lengths
As
noted
previously,
the
shortest
pipe
length
cost
scenario
(
20
meters)
are
assumed
to
be
applicable
only
to
facilities
with
flows
less
than
163,000
gpm.
Conversely,
facilities
located
on
large
waterbodies
that
are
subject
to
wave
action
and
shifting
sediment
are
assumed
to
install
the
longest
pipe
length
scenario
of
500
meters.
Large
waterbodies
in
this
instance
will
include
Great
Lakes,
oceans,
and
some
estuarine/
tidal
rivers.
The
matrix
in
Table
1­
10
will
provide
some
initial
guidance.
Generally,
if
the
waterbody
width
is
known,
the
pipe
length
should
not
exceed
half
the
width.
­
19­
TABLE
1­
10
SELECTION
OF
APPLICABLE
RELOCATION
OFFSHORE
PIPE
LENGTHS
BY
WATERBODY
Freshwater
Rivers/
Streams
Lakes/
Reservoirs
Estuaries/
Tidal
Rivers
Great
Lakes
Oceans
20
Meters
Flow
<
163,000
Flow
<
163,000
NA
NA
NA
125
Meters
TBD
TBD
TBD
NA
NA
250
Meters
TBD
TBD
TBD
TBD
NA
500
Meters
NA
NA
TBD
TBD
ALL
TBD:
Criteria
or
selection
to
be
determined;
criteria
may
include
design
flow,
waterbody
size
(
if
readily
available).

References
Whitaker,
J.
Hendrick
Screen
Company.
Telephone
Contact
Report
with
John
Sunda,
SAIC,
concerning
Tscreen
cost
and
design
information.
August
2,
&
September
9,
2002a
Whitaker,
J.
Hendrick
Screen
Company.
Email
correspondence
with
John
Sunda
SAIC
concerning
Tscreen
cost
and
design
information.
August
9,
2002b
Johnson
Screen
­
Brochure
­
"
High
Capacity
Surface
Water
Intake
Screen
Technical
Data."

Petrovs,
H.
Johnson
Screens.
Telephone
Contact
Report
Regarding
Answers
to
Passive
Screen
Vendor
Questions.

Screen
Services
­
Brochure
­
Static
Orb,
2002
Shaw,
G.
V.
&
Loomis,
A.
W.
Cameron
Hydraulic
Data.
Ingersoll­
Rand
Company.
1970
Frey,
R.
Cinergy.
Telephone
Contact
Report
Regarding
Retrofit
of
Passive
T­
Screens.
September
30,
2002.

Doley,
T.
SAIC
Memorandum
to
the
316b
Record
regarding
Development
of
Power
Plant
Intake
Maintenance
Personnel
hourly
compensation
rate.
2002
R.
S.
Means.
2001.
R.
S.
Means
Cost
Works
Database,
2001.

Metcalf
&
Eddy.
Wastewater
Engineering.
Mcgraw­
Hill
Book
Company.
1972
­
20­

Scren
Size
Number
of
Screens
Design
Flow
Compresso
r
Power
Electric
Power
Required
Low
Debris
Backwash
Frequency
High
Debris
Backwash
Frequency
Accumulato
r
recharge
time
Operating
Days
Annual
Power
Required
­

Low
Debris
Annual
Power
Required
­

High
Debris
Annual
Power
Costs
­

Low
Debris*
Annual
Power
Costs
­

High
Debris*
Annual
Labor
Required
­

Low
Debris
Annual
Labor
Cost
­

Low
Debris
Annual
Labor
Required
­

High
Debris
gpm
Hp
Kw
at
$/
kw
=
at
$/
kw
=

Events/
day
Events/
day
Hrs
Days/
yr
Kwh
Kwh
$
0.04
$
0.04
Hours
Hours
T24
1
2,500
2
1.7
2
12
0.5
365
605
3,631
$
24
$
145
272
$
10,336
608
T36
1
5,700
5
4.1
2
12
0.5
365
1,513
9,076
$
61
$
363
272
$
10,336
608
T48
1
10,000
10
8.3
2
12
0.5
365
3,025
18,153
$
121
$
726
272
$
10,336
608
T60
1
15,800
12
9.9
2
12
0.5
365
3,631
21,783
$
145
$
871
324
$
12,312
660
T72
1
22,700
15
12.4
2
12
0.5
365
4,538
27,229
$
182
$
1,089
324
$
12,312
660
T84
1
31,000
20
16.6
2
12
0.5
365
6,051
36,305
$
242
$
1,452
324
$
12,312
660
T96
1
40,750
25
20.7
2
12
0.5
365
7,564
45,382
$
303
$
1,815
324
$
12,312
660
T96
2
81,500
25
20.7
4
24
0.5
365
15,127
90,763
$
605
$
3,631
376
$
14,288
712
T96
3
122,250
25
20.7
6
36
0.5
365
22,691
136,145
$
908
$
5,446
376
$
14,288
712
T96
4
163,000
25
20.7
8
48
0.5
365
30,254
181,527
$
1,210
$
7,261
376
$
14,288
712
ATTACHMENT
A
O&
M
DEVELOPMENT
DATA
­
21­
Figure
1­
1
Capital
Costs
Conventional
Steel
Pipe
Laying
Method
At
Various
Offshore
Distances
y
=
2E­
05x
2
+
25.418x
+
388636
R
2
=
0.9995
y
=
1E­
05x
2
+
12.81x
+
249598
R
2
=
0.9993
y
=
6E­
06x
2
+
6.4038x
+
125256
R
2
=
0.9992
y
=
4E­
06x
2
+
1.1221x
+
69265
R
2
=
0.9966
$­

$
1,000,000
$
2,000,000
$
3,000,000
$
4,000,000
$
5,000,000
$
6,000,000
$
7,000,000
$
8,000,000
$
9,000,000
0
50,000
100,000
150,000
200,000
250,000
300,000
Design
Flow
gpm
Capital
Costs
125
Meter
250
Meter
500
Meter
20
Meter
­
22­
Figure
1­
2
Capital
Costs
for
Passive
Screen
Relocation
Offshore
in
Freshwater
at
Selected
Offshore
Distances
y
=
3E­
05x
2
+
63.009x
+
841363
R
2
=
1
y
=
1E­
05x
2
+
34.841x
+
608473
R
2
=
1
y
=
6E­
06x
2
+
20.609x
+
412534
R
2
=
0.9999
y
=
2E­
06x
2
+
8.7987x
+
318207
R
2
=
0.9996
$
0
$
1,000,000
$
2,000,000
$
3,000,000
$
4,000,000
$
5,000,000
$
6,000,000
$
7,000,000
$
8,000,000
$
9,000,000
$
10,000,000
$
11,000,000
$
12,000,000
$
13,000,000
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
180,000
Design
Intake
Flow
(
gpm)

Total
Capital
Costs
20
Meter
125
Meter
250
Meter
500
Meter
­
23­
Figure
1­
3
Capital
Costs
for
Passive
Screen
Relocation
Offshore
in
Saltwater
at
Selected
Offshore
Distances
y
=
3E­
05x
2
+
68.287x
+
871178
R
2
=
1
y
=
1E­
05x
2
+
37.925x
+
634921
R
2
=
1
y
=
6E­
06x
2
+
22.596x
+
437299
R
2
=
0.9999
y
=
2E­
06x
2
+
9.8641x
+
341558
R
2
=
0.9997
$
0
$
1,000,000
$
2,000,000
$
3,000,000
$
4,000,000
$
5,000,000
$
6,000,000
$
7,000,000
$
8,000,000
$
9,000,000
$
10,000,000
$
11,000,000
$
12,000,000
$
13,000,000
$
14,000,000
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
180,000
Design
Intake
Flow
(
gpm)

Total
Capital
Costs
20
Meter
125
Meter
250
Meter
500
Meter
­
24­
Figure
1­
4
Capital
Costs
for
Passive
Screen
Relocation
Offshore
in
Freshwater
with
Zebra
Mussels
at
Selected
Offshore
Distances
y
=
3E­
05x
2
+
65.418x
+
839278
R
2
=
1
y
=
1E­
05x
2
+
37.25x
+
606388
R
2
=
1
y
=
6E­
06x
2
+
23.018x
+
410449
R
2
=
1
y
=
2E­
06x
2
+
11.207x
+
316122
R
2
=
0.9997
$
0
$
1,000,000
$
2,000,000
$
3,000,000
$
4,000,000
$
5,000,000
$
6,000,000
$
7,000,000
$
8,000,000
$
9,000,000
$
10,000,000
$
11,000,000
$
12,000,000
$
13,000,000
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
180,000
Design
Intake
Flow
(
gpm)

Total
Capital
Costs
20
Meter
125
Meter
250
Meter
500
Meter
­
25­
Figure
1­
5
Total
O&
M
Cost
for
Passive
Screen
Relocated
Offshore
with
Airburst
Backwash
y
=
­
5E­
07x
2
+
0.1393x
+
16582
R
2
=
0.9246
y
=
­
6E­
07x
2
+
0.2289x
+
35945
R
2
=
0.9531
$
0
$
10,000
$
20,000
$
30,000
$
40,000
$
50,000
$
60,000
$
70,000
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
180,000
Design
Intake
Flow
Annual
O&

M
Costs
Low
Debris
High
Debris
­
26­