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12,
2004
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38
Seawater
Intake
Structure
and
Technologies
Investigation
I.
Introduction
This
study
has
been
undertaken
to
identify
suitable
technologies
to
minimize
impingement
and
entrainment
of
fish
in
typical
seawater
intake
structures
for
Offshore
and
Coastal
Oil
and
Gas
Extraction
Facilities
(
OCOGEFs)
and
Seafood
Processing
Vessels.

The
intent
is
to
identify
currently
known
technologies
and
any
"
other"
possible
technologies
to
prevent
fish
entrainment
and
mitigation
in
intake
structures.
Known
technologies
include
standard
screens,
velocity
caps
and
barrier
nets.
"
Other"
technologies
identified
include
acoustic
barriers,
air
curtains
and
electric
barriers.
Technologies
such
as
acoustic
barriers
or
electric
barriers
may
be
particularly
valuable
to
limit
impingement
on
difficult
to
modify
systems,
such
as
sea
chests.

This
investigation
also
includes
technologies
for
anti
bio­
fouling
systems.
Current
technology
includes
chemical
injection
at
the
intake,
air
sparging
of
screens
and
the
use
of
Cu­
Ni
alloys
on
the
intake
screen
surfaces.

An
alternative
technology
must
prove
to
be
practical
before
progressing
it
as
a
viable
alternative
to
current
technology.
The
primary
criteria
for
a
practical/
acceptable
alternative
configuration/
technology
is
that
it
is
successfully
implemented
at
one
or
more
facilities,
including
other
manufacturing
industries
with
a
similar
seawater
intake
structure,
anywhere
around
the
world.

I
n
addition
to
identifying
appropriate
fish
barrier
technologies,
this
study
also
aims
to
characterize
typical
seawater
intake
structures
used
by
OCOGEFs
and
Seafood
Processing
Vessels.

II.
Available
Technologies
A.
Known
Technologies
Known
technologies
evaluated
include
standard
screens,
velocity
caps,
and
barrier
nets.
It
is
assumed
that
the
reader
has
some
knowledge
of
these
"
Known
Technologies"
so
a
detailed
description
into
the
workings
of
these
technologies
has
not
been
presented.
Each
technology
is
discussed
below
with
respect
to
its
potential
use
with
OCOGEFs
and
Seafood
Processing
Vessels.

1.
Passive
Intake
Screens
­
Suitable
Passive
intake
screens
covers
the
whole
range
of
static
screens
that
act
as
a
physical
barrier
to
fish
entrainment.

These
barriers
include:
 
Simple
mesh
over
an
open
pipe
end
(
caisson
or
simple
intake
pipe)
with
a
suitably
low
face
velocity
to
prevent
impingement,
 
Grille
or
mesh
spanning
an
opening
(
as
used
on
sea
chest)
with
a
suitably
low
face
velocity
to
prevent
impingement,
 
Cylindrical
and
Tee
Wedge
Wire
Screens
designed
for
the
purpose
of
protecting
fish
stocks
(
suitable
for
caissons
or
simple
intake
pipes
but
not
sea
chests),
March
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Passive
intake
screens
are
very
commonly
used
throughout
industry
and
commercially
available
products
are
readily
available.

Tee
Screen
(
Johnson
Screens)

Fine
mesh
wedge
wire
screens
(
0.5­
1mm)
have
been
identified
(
TDD
2001
pp
5­
7)
as
having
potential
to
prevent
both
entrainment
and
impingement.
The
main
drawback
practical
with
this
fish
barrier
solution
is
that
the
screens
are
prone
to
blockages
as
a
result
of
bio­
fouling.
Since
this
type
of
equipment
is
so
common,
an
investigation
into
anti
bio­
fouling
technology
is
presented
below.

The
use
of
a
passive
intake
screen
on
a
sea
chest
(
as
used
by
some
mobile
offshore
drilling
units
(
MODUs)
and
Seafood
Processing
Vessels)
may
be
prone
to
impingement
issues.
This
is
because
the
size
of
the
opening
of
a
sea
chest
into
the
ocean
is
essentially
fixed.
To
increase
the
size
of
a
sea
chest
would
be
very
costly
due
to
significant
works
at
a
dry
dock.
A
passive
screen
that
has
a
suitably
low
face
velocity
may
therefore
have
to
protrude
outside
the
hull
of
the
vessel.
This
would
have
a
negative
impact
on
the
hydrodynamics
of
the
vessel
and
create
a
catch
point
under
the
waterline.
Alternatively,
the
passive
screen
may
be
used
in
conjunction
with
another
technology
such
as
an
acoustic
or
electro
barrier
to
reduce
impingement.

Due
to
the
success
of
passive
intake
screens
at
many
installations
around
the
world,
this
type
of
technology
is
a
suitable
fish
barrier
for
use/
retrofit
on
OCOGEFs
and
Seafood
Processing
Vessels.

2.
Velocity
Caps
­
Suitable
A
velocity
cap
is
a
device
that
is
placed
over
vertical
inlets
at
offshore
intakes.
This
cover
converts
vertical
flow
into
horizontal
flow
at
the
entrance
into
the
intake.
The
device
works
on
the
premise
that
fish
will
avoid
rapid
changes
in
horizontal
flow.
In
general,
velocity
caps
have
been
installed
at
many
offshore
intakes
and
have
been
successful
in
minimizing
impingement
(
TDD
2001).

Velocity
caps
can
reduce
fish
drawn
into
intakes
based
on
the
concept
that
they
tend
to
avoid
horizontal
flow.
They
do
not
provide
reductions
in
entrainment
of
eggs
and
larvae,
which
cannot
distinguish
flow
characteristics.
As
noted
in
ASCE
1981,
velocity
caps
are
often
used
in
conjunction
with
other
fish
protection
devices.
Therefore,
there
is
somewhat
limited
data
on
their
performance
when
used
alone
(
TDD
2001).
March
12,
2004
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Image
from
Passive
Screening
at
Surface
Water
Intakes
(
Fournier
P.
1983)

In
the
case
of
OCOGEFs
and
the
Seafood
Processing
Vessels,
velocity
caps
may
be
used
in
conjunction
with
a
passive
intake
screen
(
as
described
above).
However,
the
bio­
fouling
drawback
of
a
passive
intake
screen
would
also
be
present.
Other
possible
barriers
to
use
in
conjunction
with
a
velocity
cap
may
include
the
"
other"
technologies
noted
below
(
such
as
acoustic
barriers).

Velocity
caps,
when
use
in
conjunction
with
another
barrier
may
be
a
suitable
fish
barrier
technology
for
OCOGEFs
that
use
a
simple
pipe
intake
or
a
caisson.

The
use
of
a
velocity
cap
on
a
sea
chest
(
as
used
by
some
MODUs
and
Seafood
Processing
Vessels)
is
unlikely
to
be
a
practical
technology.
This
is
because
the
size
of
the
opening
of
a
sea
chest
into
the
ocean
is
essentially
fixed.
To
increase
the
size
of
a
sea
chest
would
very
costly
due
to
significant
works
at
a
dry
dock.
A
velocity
cap
over
the
inlet
would
therefore
have
to
protrude
outside
the
hull
of
the
vessel.
This
would
have
a
negative
impact
on
the
hydrodynamics
of
the
vessel
and
create
a
catch
point
under
the
waterline.

3.
Barrier
Nets
­
Less
Suitable
Barrier
nets
are
typically
utilized
in
locations
where
impingement
is
a
problem.
In
these
situations,
a
net
is
used
to
keep
relatively
large
fish
away
from
an
intake
screen.

Fish
net
barriers
are
wide­
mesh
nets,
which
are
placed
in
front
of
the
entrance
to
intake
structures.
The
size
of
the
mesh
needed
is
a
function
of
the
species
that
are
present
at
a
particular
site
and
vary
from
4
mm
to
32
mm
(
TDD
2001).
A
number
of
barrier
net
systems
have
been
used/
studied
at
large
onshore
power
plants.

Barrier
nets
have
clearly
proven
effective
for
controlling
impingement
(
i.
e.,
80+
percent
reductions
over
conventional
screens
without
nets)
in
areas
with
limited
debris
flows.
Experience
has
shown
that
high
debris
flows
can
cause
significant
damage
to
net
systems
(
TDD
2001).

Bio­
fouling
can
also
be
a
concern
but
this
can
be
addressed
through
frequent
maintenance.
Barrier
nets
are
also
often
only
used
seasonally,
where
the
source
water
body
is
subject
to
freezing.
Fine­
mesh
barrier
nets
show
some
promise
for
entrainment
control
but
would
likely
require
even
more
intensive
maintenance.
In
some
cases,
the
use
of
barrier
nets
may
be
further
limited
by
the
physical
constraints
and
other
uses
of
the
water
body
(
TDD
2001).
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Barrier
nets
are
not
suitable
(
practical)
for
use
on
seafood
processing
vessels
or
MODUs
since
the
net
would
be
a
major
hindrance
to
the
operation
of
the
vessel.

Fixed
platforms
may
potentially
use
barrier
nets
to
reduce
impingement
problems.
The
configuration
that
may
be
practical
is
to
set
the
nets
up
in
removable
panels
around
the
intake.
At
this
stage,
an
example
of
this
type
of
panelled
net
configuration
is
not
available.

4.
Perforated
Intake
Pipe
 
Less
Suitable
A
perforated
pipe
arrangement
draws
water
through
perforations
or
elongated
slots
in
a
cylindrical
section
placed
in
the
water
body.
Early
designs
of
this
technology
were
not
efficient,
velocity
distribution
was
poor,
and
they
were
specifically
designed
to
screen
out
detritus
(
i.
e.,
not
used
for
fish
protection)
(
TDD
2001).

Perforated
caissons
or
simple
pipes
have
been
used
on
some
fixed
platforms.
For
example:
Marathon
South
Pass
(
Block
86)
use
a
20"
inner
diameter
simple
pipe
with
bottom
at
59'
below
water
level.
The
lower
8'
pipe
section
is
slotted
with
bottom
open,
slots
are
1"
W
x
4"
L,
slots
spaced
3"
apart
along
circumference
and
8"
apart
vertically
(
from
Tetratech
2003
Draft
Oil
and
gas
platform
CWIS
data).

Since
impingement
and
entrainment
performance
data
for
perforated
pipe
arrangements
are
unavailable,
the
use
of
this
technology
is
questionable.
In
general,
EPA
projects
that
perforated
pipe
system
performance
should
be
comparable
to
wide­
mesh
wedge
wire
screens
(
eg.
at
Eddystone
Units
1
and
2
and
Campbell
Unit
3)
(
TDD
2001).

Perforated
Intake
Pipe
(
Thompson
Culvert
Company)

5.
Travelling
Screens
(
includes
Angular
and
Modular
Screens)
­
Unsuitable
Travelling
screens
are
generally
used
on
onshore
facilities
that
incorporate
large
stilling
and
pump
pits.
The
travelling
screen
installation
requires
a
significant
amount
of
specifically
designed
structure
to
be
included
in
the
intake
design.
Retrofitting
a
structure
that
to
accept
a
travelling
screen
on
an
OCOGEF
or
Seafood
Processing
Vessel
would
be
impractical
and
extremely
costly.
Furthermore,
the
maintenance
of
a
sub­
sea
travelling
screen
retrofitted
to
an
existing
structure
would
also
be
impractical
and
very
costly.

The
design
of
travelling
intake
screens
is
not
suited
to
either
OCOGEFs
or
Seafood
Processing
Vessels.
As
such,
this
technology
has
been
deemed
to
be
unsuitable
for
these
facilities.
March
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6.
Porous
Dykes
and
Leaky
Dams
­
Unsuitable
Porous
dykes,
also
known
as
leaky
dams
or
dykes,
are
filters
resembling
a
breakwater
surrounding
a
cooling
water
intake.
The
core
of
the
dyke
consists
of
cobble
or
gravel
that
permits
free
passage
of
water.
The
dyke
acts
both
as
a
physical
and
behavioral
barrier
to
aquatic
organisms.
Tests
conducted
to
date
have
indicated
that
the
technology
is
effective
in
excluding
juvenile
and
adult
fish.
The
major
problems
associated
with
porous
dykes
come
from
clogging
by
debris
and
silt,
ice
build­
up,
and
by
colonisation
of
fish
and
plant
life
(
TDD
2001).

Clearly
the
construction
of
a
fixed
major
civil
installation
such
as
a
porous
dam
or
leaky
dyke
is
not
possible
for
MODUs
or
Seafood
Processing
Vessels.
The
use
of
this
type
of
equipment
on
fixed
platforms
may
also
be
rejected
due
to
the
fact
that
if
one
were
constructed
in
the
middle
of
the
ocean
it
would
be
extremely
impractical
and
costly
and
result
in
the
death
or
dislocation
of
a
large
number
of
marine
wildlife.

As
such,
this
technology
has
been
deemed
to
be
unsuitable
for
the
facilities
investigated
here.

B.
"
Other"
Technologies
Other
technologies
reviewed
include
acoustic
barriers,
air
curtains,
electro
fish
barriers,
intake
location,
keel
cooling,
and
strobe
lights
and
illumination.
Each
technology
is
discussed
below
with
respect
to
its
potential
use
in
minimizing
impingement
and
entrainment
at
OCOGEFs
and
Seafood
Processing
Vessels.

1.
Acoustic
Barriers
­
Potentially
Suitable
with
Further
Development
Although
there
is
simplicity
in
the
concept
of
an
acoustic
fish
deterrent,
it
is
apparent
that
the
use
of
sound
for
fish
repulsion
is
not
a
simple
task.
The
use
of
sound
has
been
established
as
an
effective
means
of
repelling
many
species
of
fish.
The
major
problems
with
acoustic
barriers
are
that
some
sounds
repel
some
fish
yet
have
no
effect
or
attract
others,
and
fish
may,
over
time,
become
desensitized
to
a
sound
that
would
otherwise
scare
them
away.

There
have
been
a
number
of
studies
undertaken
on
specific
fish
entrainment
issues
at
specific
locations.
However,
from
a
commercial
perspective,
supply
of
acoustic
barrier
equipment
is
not
commonly
available.
Fish
Guidance
Systems
Limited
(
FGS)
from
Southampton
in
the
United
Kingdom
design
and
manufacture
a
range
of
acoustic
barriers
for
large
industrial
water
intakes.

For
fish
to
be
repelled
by
a
sound,
a
number
of
criteria
must
be
met
(
derived
from
www.
fish­
guide.
com):
1.
The
fish
must
be
able
to
detect
the
frequencies
used
to
compose
the
deterrent
signal.
2.
The
sound
signal
composition
must
be
of
a
type
that
is
repellent
to
fish
(
some
sounds
attract,
others
have
no
effect);
3.
The
level
of
the
sound
must
be
high
enough
to
elicit
a
reaction,
taking
account
of
background
noise.

The
background
noise
issue
is
important,
especially
where
acoustic
systems
are
deployed
near
underwater
machinery
such
as
pumps
and
turbines.
In
such
cases,
it
may
be
necessary
to
measure
the
underwater
noise
spectra
under
typical
operating
conditions.
March
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2004
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Underwater
noise
may
be
repellent
to
fish
if:
a)
Noise
of
any
type
having
frequencies
that
lie
within
the
fish
hearing
range
is
emitted
at
very
high
audio
levels
(
but
this
is
very
expensive
and
may
impact
other
biota);
b)
The
characteristics
of
the
noise
have
any
special
biological
meaning
to
the
fish
(
e.
g.,
mimicking
the
approach
of
a
predator);
c)
The
noise
is
designed
by
experimentation
to
cause
particularly
strong
avoidance.

The
biological
approach
(
b)
may
offer
good
possibilities
for
individual
species,
but
the
empirical
approach
(
c)
has
yielded
a
number
of
signal
types
that
are
effective
against
a
wide
range
of
species.

The
signal
types
that
have
proved
most
effective
in
all
applications
are
based
on
artificially
generated
waveforms
that
rapidly
cycle
in
amplitude
and
frequency
content,
thus
reducing
habituation.
A
human
equivalent
would
be
being
made
to
stand
near
to
a
wailing
police
or
ambulance
siren.
It
simply
gets
uncomfortable,
so
you
move
away.

In
practice,
considerable
attention
needs
to
be
given
to
the
design
and
specification
of
a
system
to
ensure
it
achieves
high
fish
deflection
efficiencies.
Key
variables
include
the
type
of
fish,
background
noise,
hydraulic
conditions
(
eg.
intake
velocities,
attraction
flow
to
the
fish
pass)
and
acoustic
design.

Acoustic
systems
may
be
designed
primarily
either
to
block
or
to
deflect
fish
movement.

Sound
Projector
Array
(
SPA)
system
blocking/
deflecting
fish
movements
at
a
water
intake
Deflection
is
usually
the
best
course
of
action,
as
the
fish
are
moved
swiftly
from
the
source
of
danger
(
e.
g.,
water
intake)
into
a
safe
flow.
Blocking
can
be
more
difficult
if
the
fish
are
not
moved
away
from
the
area,
as
the
risk
of
habituation
to
the
sound
signals
becomes
increased.
This
can
be
overcome
to
some
extent
by
changing
the
signal
pattern
at
intervals
but
acoustic
deterrents
are
essentially
a
mild
form
of
stimulus
less
effective
than
electric
barriers
purely
for
blocking.
For
this
reason
it
is
advised
that
a
well­
designed
and
suitably
placed
bypass
facility
be
provided.

Sound
projectors
are
electro­
mechanical
devices
and
regular
maintenance
of
them
is
required
to
ensure
optimum
performance.
This
involves
removing
the
underwater
units
to
replace
perished
seals
and
to
check
moving
components.
Also,
it
is
desirable
to
raise
and
clean
the
units
occasionally
to
remove
any
build­
up
of
silt
or
March
12,
2004
­
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7
of
38
fouling.
It
is
necessary
to
provide
a
deployment
system
to
bring
sound
projectors
to
the
surface
for
maintenance,
without
the
need
to
use
divers.
As
it
is
difficult
to
check
the
performance
of
submerged
equipment,
diagnostic
units
can
be
attached
to
the
control
electronics
to
monitor
performance
of
the
sound
projectors.

Examples
of
Acoustic
Barrier
Installations:

It
must
be
noted
that
the
examples
of
Acoustic
Barriers
did
not
include
any
facilities
that
fall
into
the
categories
of
OCOGEFs
or
Seafood
Processing
Vessels.
However,
the
following
installations
share
similarities
with
fixed
offshore
structures.
The
use
of
this
equipment
on
sea
chests
or
mobile
equipment
may
be
possible
but
is
not
proven
by
example.

Doel
Power
Station
­
SPA
System:

Doel
nuclear
power
station
operated
by
Electrabel
responded
to
concerns
expressed
by
environmental
regulators
and
fishermen
to
reduce
the
numbers
of
fish
that
were
being
drawn
into
their
cooling
water
intake
each
year.
The
main
species
being
affected
were
herring
and
sprat
(
clupeid
family).

In
1997,
a
SPA
fish
deterrent
system
was
designed
and
installed
on
the
offshore
intake.
In
total,
20
large
FGS
Mk
II
30­
600
sound
projectors
were
installed
to
create
a
repellent
sound
field
close
to
the
water
intake
openings
causing
passing
fish
to
veer
away.
A
multiple
signal
generator
was
used
to
avoid
resident
species
habituating
to
any
one
sound
signal.
To
allow
servicing
of
the
fish
deterrent
system
while
the
station
is
still
operating,
a
deployment
frame
has
been
installed
to
lower
sound
projectors
into
their
optimum
position
and
to
allow
them
to
be
raised
for
routine
inspections
and
maintenance.

The
acoustic
installation
has
subsequently
undergone
a
number
of
evaluation
trials
by
researchers
from
Belgium's
Leuven
University.
Independent
trials
have
shown
a
reduction
in
the
target
species
by
98%.
In
addition,
the
catch
of
other
non­
target
species
has
been
reduced
with
the
overall
reduction
being
81%.

Foss
Flood
Relief
Pumping
Station
SPA
System:

The
Environment
Agency
responded
to
a
fish
kill
at
the
River
Foss
Flood
Alleviation
Pumping
Scheme
in
York
(
UK).
The
scheme
consists
of
a
barrier
gate
to
prevent
floodwater
from
the
River
Ouse
flowing
up
the
River
Foss.
Water
flowing
down
the
Foss
is
pumped
from
the
upstream
side
of
the
floodgate
by
eight
vertical,
axial
flow
propeller
pumps,
and
discharged
below
the
gate.
Fish
damage
was
attributable
to
contact
with
moving
machinery
and
rapid
pressure
changes
during
passage
through
the
pumps.
March
12,
2004
­
Page
8
of
38
In
1994,
an
acoustic
fish
deflection
system
was
installed
to
deflect
fish
away
from
pumps
prior
to
and
during
operation.
As
the
pump
inlets
formed
a
popular
shelter
for
resident
fish,
the
acoustic
system
was
designed
to
start
operating
15
minutes
prior
to
the
pumps
operating.
The
SPA
installation
also
provided
important
protection
to
resident
fish
while
the
pumps
were
operating
by
creating
a
gradient
of
deterrent
sound,
increasing
towards
the
intake
openings.
The
installation
comprised
six
FGS
Mk
I
Model
30­
600
sound
projectors.

A
series
of
independent
trials
were
performed
to
test
the
effectiveness
of
an
acoustic
fish
deterrent
system
in
1994.
Coarse
fish
representing
12
species
were
captured
during
the
trial.
The
most
abundant
species
were
bleak,
dace,
chub,
perch
and
common
bream.
Prior
to
the
trial,
it
was
previously
considered
that
the
sudden
commencement
of
pumping
accounted
for
a
larger
proportion
of
the
fish
entrained
through
the
pumps,
as
the
enclosed
environment
of
the
pump
channels
provided
a
potential
refuge
for
fish.
It
was
found
that
the
majority
of
fish
were
drawn
into
the
Foss
Basin
during
pumping.
The
acoustic
system
was
found
to
reduce
overall
fish
entrainment
by
80%
with
the
system
deflecting
fish
in
the
pumpwells
and
outside
the
Foss
Basin
during
operation.

Other
Installations:

August
2000
­
Central
Hidroelectrica
de
Allones,
Spain:
Four
15­
100
Sound
Projector
Array
system
supplied
to
deflect
fish
away
from
a
head
race
channel
entrance.

July
2000
­
Blackdyke
Water
Transfer
Pumping
Station,
UK:
Eight
15­
100
Sound
Projector
Array
system
supplied
to
deflect
fish
out
of
pumping
station
chambers,
prior
to
and
during
water
transfers.

July
2000
­
Great
Yarmouth
CCGT,
UK:
Eight
30­
600
Sound
Projector
Array
system
supplied
for
cooling
water
system
to
new
CCGT
power
station.

June
2000
­
Shoreham
CCGT,
UK:
Six
30­
600
Sound
Projector
Array
system
supplied
for
cooling
water
intake
to
new
CCGT
power
station.

April
2000
­
Drinking
Water
Abstraction,
River
Stour,
UK:
Six
15­
100
Sound
Projector
Array
system
supplied
for
drinking
water
abstraction.

Acoustic
Barrier
Conclusions
Acoustic
barriers
have
proven
to
be
effective
as
fish
impingement
and
entrainment
barriers.
Since
there
is
no
fine
mesh
covering
the
intake,
this
type
of
barrier
is
not
prone
to
issues
with
bio­
fouling.

This
equipment
type
of
equipment
is
commercially
available
and
has
been
proven
effective
at
a
number
of
locations.
March
12,
2004
­
Page
9
of
38
The
typical
application
of
this
technology
has
been
onshore­
based
intake
structures
rather
than
OCOGEFs
or
Seafood
Processing
Vessels.
The
transfer
of
this
technology
to
OCOGEFs
or
Seafood
Processing
Vessels
intake
structures
may
be
possible
with
further
development.
It
is
particularly
interesting
for
fitting
to
sea
chest
intake
structures.

2.
Air
Curtains
­
Potentially
Suitable
with
Further
Development
Air
curtains
are
simply
a
screen
of
bubbles
used
to
guide
fish
away
from
an
intake
structure.
Air
bubbles
have
proven
to
have
some
effect
for
herding
and
guiding
fish
or
as
a
barrier
to
their
normal
activity
(
Bibko
et
al.
1973).
However,
the
effectiveness
of
air
bubble
curtains
at
water
intakes
varies
greatly
(
NEST,
1996).
Northeast
Science
and
Technology
(
NEST)
undertook
a
detailed
study
into
the
effectiveness
of
many
different
types
of
technology
for
preventing
lake
Sturgeon
impingent
and
entrainment
for
the
Little
Long
Generating
Station
Facilities
(
NEST
Technical
Report
TR­
031
1996).
This
facility
is
located
in
Northeastern
Ontario
on
the
Mattagami
River
and
represents
one
of
the
last
refuges
for
lake
Sturgeon.

Overall,
air
curtains
on
their
own
do
not
effectively
deter
fish
or
substantially
reduce
impingement
(
Zweiacker
et
al.
1977;
Lieberman
and
Muessig
1978;
Patrick
et
al.
1988:
NEST
1996).
Factors
that
reduce
the
effectiveness
of
an
air
curtain
include:

 
water
temperature
(
Bibko
et
al.
1973),
 
fish
crowding
(
Smith.
1971),
 
the
presence
of
predators
(
Smith.
1971),
 
levels
of
light
(
Alevras
1973).

The
effectiveness
of
an
air
curtain
may
be
improved
when
used
in
combination
with
acoustic
deterrents.
When
a
pneumatic
popper
is
used
in
combination
with
an
air
curtain,
there
is
an
improved
overall
effectiveness.
This
same
effect
is
not
observed
with
use
of
strobe
lights
(
Patrick
et
al.
1988).

Supply
of
air
curtain
and
acoustic
barrier
equipment
is
not
commonly
available.
Fish
Guidance
Systems
Limited
(
FGS)
from
Southampton
in
the
United
Kingdom
design
and
manufacture
a
device
that
utilizes
both
a
bubble
curtain
and
an
acoustic
deterrent
for
large
industrial
water
intakes.

Example
Design
of
a
Bubble
Curtain
/
Acoustic
System
(
derived
from
www.
fishguide
com):

Bio
­
Acoustic
Fish
Fence
(
BAFF)
system
guiding
fish
movements
towards
a
fish
pass
March
12,
2004
­
Page
10
of
38
The
BAFF
is
used
to
divert
fish
from
a
major
flow,
e.
g.,
entering
a
turbine,
into
the
minor
flow
of
a
fish
pass
channel.
It
may
be
regarded
as
analogous
to
a
conventional
angled
fish
screen.
It
uses
an
air
bubble
curtain
to
contain
a
sound
signal
that
is
generated
pneumatically.
Effectively,
this
creates
a
"
wall
of
sound"
(
an
evanescent
sound
field)
field
that
can
be
used
to
guide
fish
around
river
structures
by
deflection
into
fish
passes.

Physically,
the
BAFF
comprises
a
pneumatic
sound
transducer
coupled
to
a
bubblesheet
generator,
causing
sound
waves
to
propagate
within
the
rising
curtain
of
bubbles.
The
sound
is
contained
within
the
bubble
curtain
as
a
result
of
refraction,
since
the
velocity
of
sound
in
a
bubble­
water
mixture
differs
from
that
in
either
water
or
air
alone.
The
sound
level
inside
the
bubble
curtain
may
be
as
high
as
170
dB
re
1mPa,
typically
decaying
to
5%
of
this
value
within
0.5­
1
m
from
the
bubble
sheet.
It
can
be
deployed
in
much
the
same
way
as
a
standard
bubble
curtain,
but
its
effectiveness
as
a
fish
barrier
is
greatly
enhanced
by
the
addition
of
a
repellent
sound
signal.
The
characteristics
of
the
sound
signals
are
similar
to
those
used
in
SPA
systems,
i.
e.,
within
the
20­
500
Hz
frequency
range
and
using
frequency
or
amplitude
sweeps.

FGS
acoustic
BAFF
systems
comprise
the
following
components:

 
BAFF
Unit:
The
BAFF
system
comprises
of
modular
sections,
each
2.4
m
long,
which
are
linked
together
to
form
the
required
length.
The
acoustic
signal
is
entrapped
in
the
bubbles
by
a
driver
unit
and
the
resulting
'
wall
of
sound'
produces
an
uninterrupted
guidance
system.
 
Air
Blower
or
Compressor:
The
BAFF
uses
an
air
blower
or
compressor
to
supply
pressurised
air
to
create
a
continuous
bubble
curtain.
 
Air
Blower
/
Compressor
Pipe:
A
temperature
/
pressure
resistant
pipe
delivers
air
from
the
air
blower
or
compressor
to
the
BAFF
control
equipment.
 
BAFF
Control
Equipment
and
Control
Lines:
The
BAFF
control
equipment
is
used
to
operate
the
BAFF
system.
A
main
air
supply
and
two
control
lines
feed
driver
units
fitted
on
each
of
the
BAFF
units.
Solenoids
located
in
the
returning
control
line
regulate
the
airflow
to
the
driver
units.
Pressure
feedback
lines
run
from
the
BAFF
units
back
to
the
control
panel
to
allow
pressure
within
the
BAFF
to
be
monitored.
An
alarm
system
indicates
a
sudden
drop
in
pressure
resulting
from
a
failure
in
air
supply.

Examples
of
Air
Curtain
/
Acoustic
Barrier
Installations:

I
t
must
be
noted
that
the
examples
found
did
not
include
any
facilities
that
fall
into
the
categories
of
OCOGEFs
or
Seafood
Processing
Vessels.
However,
the
following
installations
share
similarities
with
fixed
offshore
structures.
The
use
of
this
equipment
on
sea
chests
or
mobile
equipment
may
be
possible
but
is
not
proven
by
example.

Beeston
Hydro­
electric
Station:

Beeston
Weir
Hydro
Scheme,
a
1.3MW
station
was
commissioned
in
May
2000.
The
£
3
million
Beeston
Hydro
Scheme
was
installed
at
an
existing
weir
on
the
River
Trent
near
Nottingham
in
the
UK.
A
prime
objective
of
the
new
hydro
was
to
make
the
scheme
fit
the
environment,
and
not
the
other
way
around.
March
12,
2004
­
Page
11
of
38
The
river
supports
a
mixed
population
of
resident
coarse
fish
and
migratory
eels.
Owing
to
a
history
of
poor
water
quality,
the
river
currently
has
a
very
small
population
of
salmonoid
fish.
However,
the
Environment
Agency
has
a
program
underway
of
continuous
improvement
of
water
quality,
with
the
goal
of
restoring
the
salmonoid
population.

To
divert
downstream
migrating
fish
away
from
the
headrace
channel,
a
80m
long
BAFF
was
installed.
It
is
located
diagonally
upstream
of
the
weir
to
guide
juvenile
salmon
and
other
fish
moving
downstream
to
the
fish
ladder.
A
new
vertical
single
slot
fish
pass
was
added
to
facilitate
upstream
and
downstream
passage
of
both
salmonoid
and
coarse
fish,
prior
to
construction
of
the
hydro
facility.

The
BAFF
system
produces
a
"
wall
of
underwater
sound"
by
using
compressed
air
to
generate
a
continuous
bubble
curtain
into
which
low
frequency
sound
(
varying
between
50
and
500
Hertz)
is
injected
and
entrapped.
Although
well­
defined
lines
of
high
level
sound
(
at
least
160
decibels)
are
generated
within
the
bubble
curtain,
the
noise
levels
are
negligible
a
few
meters
away
from
it.
By
restricting
the
sound
curtain
to
a
small
area,
the
system
allows
fish
to
act
normally
throughout
the
remainder
of
the
reservoir
or
river.

A
Smith­
Root
graduated
electric
barrier
is
located
just
below
the
power
plant
to
divert
adult
salmon
migrating
upstream
away
from
the
tailrace
and
into
the
fish
ladder.

Other
Installations:

August
2000
­
Backbarrow
Hydro,
UK:
Eleven
units
BAFF
system
supplied
to
guide
fish
in
headrace
channel
to
a
purpose
built
by
wash.

Spring
1996
­
Blantyre,
Hydro
Station,
Scotland,
UK:
Combined
Sound
Projector
Array
and
BAFF
system
installed
on
low­
head
hydro­
electric
power
station
for
evaluation
trials.
Results
published
in
ETSU
report
H/
01/
00046/
REP
www.
dti.
gov.
uk/
NewReview/
nr32/
html/
fish.
html
January
1999
­
Northampton,
Inland
Waterway
Pumping
Station,
UK
Two
bubble
curtain
system
installed
on
canal
pumping
station
intake
to
reduce
transfer
of
zander.

Air
Curtain
Conclusions
Air
curtains
have
proven
to
be
ineffective
barriers
to
impingement
and
entrainment
of
fish
stocks
when
they
are
use
on
their
own.
When
used
in
combination
with
other
acoustic
deterrent
systems,
their
effectiveness
is
greatly
increased.
This
equipment
type
of
equipment
is
commercially
available
and
has
been
proven
effective
at
a
number
of
locations.
March
12,
2004
­
Page
12
of
38
The
typical
application
of
this
technology
has
been
on
hydro­
electric
power
station
intake
structures
rather
than
OCOGEFs
or
Seafood
Processing
Vessels.
The
transfer
of
this
technology
to
OCOGEFs
or
Seafood
Processing
Vessels
intake
structures
may
be
possible
with
further
development.
As
such,
this
technology
has
the
potential
to
become
suitable
after
further
development.

3.
Electro
Fish
Barriers
­
Potentially
Suitable
with
Further
Development
Electrical
fields
are
frequently
used
to
frighten,
attract,
stun
or
kill
fish.
On
approaching
the
field,
many
fish
exhibit
a
fright
reaction
and
may
be
repelled
(
NEST
1996).

The
following
information
was
obtained
from
the
Smith­
Root
web
page
(
www.
smithroot
com).
Smith­
Root
is
a
leading
supplier
of
Electro
Fish
barriers:

Electric
current
passing
between
the
electrodes,
via
the
water
medium,
produces
an
electric
field.
When
fish
are
within
the
field,
they
become
part
of
the
electrical
circuit
with
some
of
the
current
flowing
through
their
body.
The
electric
current
passing
through
fish
can
evoke
reactions
ranging
from
a
slight
twitch
to
full
paralysis,
depending
on
the
current
level
and
shock
duration
they
receive.
(
Smith­
Root.
com)

One
of
the
most
important
advantages
of
the
parallel
field
orientation
is
that
when
a
fish
is
crosswise
to
the
electric
field
it
receives
almost
no
electric
shock.
Fish
learn
very
quickly
that
by
turning
side
ways
to
the
flow
they
can
minimize
the
effects
of
the
electric
field.

Examples
of
Electro
Fish
Barrier
Installations:

Great
Lakes
Division
­
80"
Mill,
Pump
House
#
2
(
1994):

Location:
Ecorse,
Michigan
Barrier
Type:
Smith­
Root
Concrete
weir
with
bottom
mounted
electrodes.
March
12,
2004
­
Page
13
of
38
Keeps
gizzard
shad
and
other
river
fish
from
entering
the
pumping
systems
used
for
steel
mill
cooling.
Previously,
dense
fish
runs
caused
several
shutdowns
each
year.
Since
installation
in
1994,
they
have
not
had
single
shutdown
attributed
to
fish
runs.

Shields
Lake
Forest
Lake,
Minnesota
1996:
Barrier
Type:
Smith­
Root
Plastic
culvert
with
stainless
steel
electrodes.
Keeps
carp
from
entering
Shields
Lake.

Heron
Lake
Worthington,
Minnesota
1993
Barrier
Type:
Smith­
Root
Concrete
weir
with
bottom
mounted
electrodes.
Keeps
carp
from
entering
Heron
Lake.
Barrier
is
very
effective
and
currently
in
operation.
This
once
sterile
lake
is
now
restored
to
a
bird
and
game
fish
habitat.
March
12,
2004
­
Page
14
of
38
Electro
Fish
Barrier
Conclusions
Electro
Fish
Barriers
have
proven
to
be
effective
as
fish
impingement
and
entrainment
barriers.
The
main
limitation
is
that
the
high
conductivity
of
seawater
limits
the
size
of
a
practical
electro
barrier.
Discussions
with
a
supplier
of
this
type
of
equipment
(
Smith­
Root)
stated
that
a
practical
installation
would
be
possible
at
a
caisson
or
sea
chest
opening.

Electro
Fish
Barriers
are
commercially
available
and
have
been
shown
to
be
effective
at
a
number
of
locations.
The
most
common
location
for
this
technology
to
be
used
is
on
river
or
lake
intake
locations
for
power
stations
where
local
fish
stocks
are
to
be
protected.

The
typical
application
of
this
technology
has
been
onshore­
based
intake
structures
rather
than
OCOGEFs
or
Seafood
Processing
Vessels.
The
transfer
of
this
technology
to
OCOGEFs
or
Seafood
Processing
Vessels
intake
structures
may
be
possible
with
further
development.
As
such,
this
technology
has
the
potential
to
become
suitable
after
further
development.
It
is
particularly
interesting
for
fitting
to
sea
chest
intake
structures.

4.
Intake
Location
­
Potentially
Suitable
with
Further
Development
Beyond
technology
design
alternatives,
an
operator
may
able
to
locate
cooling
water
intake
structures
offshore
or
otherwise
in
areas
that
minimize
entrainment
and
impingement
(
compared
to
conventional
onshore
locations).
It
is
well
known
that
there
are
certain
areas
within
every
waterbody
with
increased
biological
productivity,
and
therefore
where
the
potential
for
entrainment
and
impingement
of
organisms
is
higher
(
TDD
2001).

I
n
oceans,
nearshore
coastal
waters
are
generally
the
most
biologically
productive
areas.
The
euphotic
zone
(
zone
of
photosynthetic
available
light)
typically
does
not
extend
beyond
the
first
100
meters
(
328
feet)
of
depth.
Therefore,
nearshore
waters
are
generally
more
productive
due
to
photosynthetic
activity,
and
due
to
the
input
from
estuaries
and
run­
off
of
nutrients
from
land
(
TDD
2001).

Woodside
Energy
Limited
in
Western
Australia
(
See
Appendix
A
for
interview
notes)
indicated
that
the
depth
of
the
intake
structure
may
be
used
as
a
method
of
controlling
fish
entrainment
in
the
OCOGEF
seawater
intake
structures.
Unfortunately,
no
further
details
on
the
systems
that
are
employed
by
Woodside
are
currently
known.

I
ntake
Location
Conclusions
I
ntake
location
appears
to
offer
potential
in
reducing
entrainment
and
impingement
of
marine
organisms.
This
type
of
technology
may
be
implemented
on
fixed
platforms
that
are
located
in
deep
water.
A
detailed
marine
study
into
the
density
of
organisms
would
be
required
for
this
approach
to
be
successful.
This
type
of
technology
is
not
suitable
for
MODUs
or
Seafood
Processing
Vessels
since
they
would
operate
in
various
locations,
depths
and
environments.
Furthermore,
a
variable
depth
sea
chest
would
be
impractical
(
if
not
impossible).
March
12,
2004
­
Page
15
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38
5.
Keel
Cooling
­
Potentially
Suitable
with
Further
Development
Keel
cooling
is
a
process
which
bypasses
the
need
to
draw
cooling
water
on
board
a
vessel.
This
is
achieved
by
installing
a
heat
exchanger
in
the
waterbody
and
pumping
cooling
water
through
a
closed
loop
system.
This
technology
was
developed
during
the
Second
World
War
and
is
commonly
used
on
many
vessels
today.
The
Shine
Fisheries
Factory
Trawlers
operating
out
of
Fremantle
in
Western
Australia
use
keel
cooling
for
all
cooling
water
on
all
of
their
vessels.

Keel
(
Grid)
Cooler
Configurations
(
Fernstrum
Company
and
Flagship
Marine)

Fernstrum
Company
(
Frank
Bjorkman)
has
confirmed
that
this
system
is
suitable
for
retrofitting
to
an
existing
on­
board
cooling
water
system.
Furthermore,
it
is
not
limited
to
mobile
vessels.
The
coolers
may
be
designed
using
natural
convection
(
fixed
structure)
rather
than
forced
convection
(
moving
structure)
to
meet
a
heat
transfer
requirement.
Therefore,
this
equipment
could
be
used
on
the
cooling
water
systems
of
stationary
or
mobile
OCOGEFs
or
Seafood
Processing
Vessels.
It
is
believed
that
Brown
and
Root
installed
one
of
the
Fernstrum
systems
on
a
new
OCOGEF
some
20
years
ago.
Unfortunately
details
of
this
system
are
currently
unavailable.

Bio­
fouling
of
keel
coolers
is
limited
with
the
use
of
Cu­
Ni
alloys
for
fabrication.
See
Anti
Bio­
fouling
Technologies
below.

Keel
Cooling
Conclusions
Keel
cooling
is
a
suitable
technology
for
all
types
Seafood
Processing
Vessels.
OCOGEFs
may
also
be
able
to
benefit
from
this
technology.
March
12,
2004
­
Page
16
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38
6.
Strobe
lights
and
Illumination
­
Unsuitable
The
reaction
of
fish
to
light
is
not
consistent.
It
changes
with
the
type
of
light,
intensity,
angular
distribution,
polarization
and
duration
(
Hocutt
1980).
Some
fish
may
exhibit
a
positive
response
to
a
light
source
while
the
same
light
may
repel
others.
Also,
the
reaction
of
a
fish
to
a
light
source
may
vary
depending
on
the
life
stage
of
the
particular
species
(
Fore
1969).
Studies
have
been
undertaken
into
the
use
of
strobe
lights.
The
effectiveness
of
a
strobe
has
been
found
to
vary
with
species,
time
of
day
and
fish
size
(
Taft
et
al
1987).

Compared
with
other
behavioural
barriers,
strobe
lights
and
other
illumination
generally
appear
to
be
the
least
effective.
A
combination
of
strobe
lights
and
air
curtains
are
more
effective
for
repelling
fish
than
either
on
their
own
but
were
less
effective
than
the
air
curtain
/
acoustic
deterrents
(
NEST
1996).

Strobe
lights
and
Illumination
Conclusions
Based
on
the
above
research,
strobe
lights
and
illumination
may
be
rejected
as
a
suitable
technology
on
their
own.
However,
their
use
in
combination
with
other
technologies
may
prove
to
be
successful.

III.
Anti
Bio­
fouling
Technologies
Several
anti
bio­
fouling
technologies
are
available
including
air
sparges,
copper­
nickel
(
Cu­
Ni)
alloys,
chemical
injection,
and
hot
kill.
Each
technology
and
its
potential
application
to
OCOGEFs
and
Seafood
Processing
Vessels
is
discussed
below.
Bio­
fouling
past
any
intake
fish
barrier
(
i.
e.,
inside
the
piping
system)
is
outside
this
scope
of
work
and
will
not
be
considered.

A.
Air
Sparges
 
known,
suitable
The
use
of
compressed
air
(
air
sparges)
to
physically
remove
bio
matter
from
a
screen
face
is
commonly
used
in
industry.
It
is
particularly
useful
when
drifting
seaweed
or
trash
(
such
as
plastic
bags)
impinges
on
the
screen
face.
This
is
a
suitable
technology
in
most
marine
areas.
In
the
case
that
there
are
prolific
marine
organisms
that
may
grow
on
the
screen
surface
such
as
molluscs
(
zebra
mussel),
corral
or
seaweed
growth,
further
methods
may
need
to
be
taken
to
protect
the
screen,
such
as
use
of
specific
materials
or
"
hot
kill"
which
are
described
later
in
this
section.

Air
Sparging
a
Tee
Screen
(
Johnson
Screens)
March
12,
2004
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Page
17
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38
B.
Cu­
Ni
Alloys­
known,
suitable
Alloys
of
copper
and
nickel
have
been
found
to
limit
marine
growth
on
a
submerged
surface.
These
alloys
are
used
in
the
manufacture
of
screen
surfaces
to
prevent
problems
with
invasive
marine
growth.

Johnson
Screens
offer
screens
manufactured
from
"
Z
Alloy"
(
90/
10
CuNi).
Note:
This
material
is
commonly
used
for
other
sea
water
equipment
(
such
as
in
plate
types
heat
exchangers).

Z
Alloy
Product
Demonstrations
from
Johnson
Screens
This
technology
has
proven
to
be
suitable
for
seawater
fabricated
screen
applications.

C.
Chemical
Injection
 
known,
unsuitable
There
are
many
chemicals
that
may
be
used
to
prevent
bio­
fouling
of
sea
water
systems.
These
include
solutions
of
chlorine,
copper
and
many
other
possible
biocides.
These
systems
are
generally
designed
to
mix
in
with
the
intake
flow
and
protect
the
down
stream
process
rather
than
the
screen
face.
It
would
be
very
difficult
and
expensive
to
design
a
chemical
system
to
protect
an
entire
intake
screen
from
bio­
fouling.
Furthermore,
there
would
be
a
significant
impact
to
the
environment
around
the
intake
structure.
Therefore,
chemical
injection
for
the
protection
of
an
intake
barrier
is
considered
impractical
and
not
a
suitable
technology
for
this
purpose.

D.
Hot
Kill
 
other,
potentially
suitable
The
Hot
Kill
process
involves
recirculating
hot
water
back
through
the
intake
structure
to
kill
any
marine
growth
than
may
have
attached
to
the
intake
pipe
or
screen.

Kwinana
Power
Station
is
a
medium
sized
multi
fuel
(
gas,
oil
andcoal)
power
station
that
has
operated
in
Cockburn
Sound
Western
Australia
for
more
than
40
years.
The
Sound
is
the
natural
habitat
of
the
Blue
Mussel,
which
grows
prolifically
throughout
the
area.
The
power
station
was
designed
with
two
separate
intake
systems
(
one
unit
on
line,
the
other
off
line).
The
intake
systems
include
a
sub
sea
screened
intake
(
mesh
size
unknown),
inlet
pipe
of
approximately
500m
and
an
onshore
concrete
stilling
sump
with
travelling
(
rotatory)
screens.
Auto
chlorination
(
electrolysis)
is
used
to
treat
the
water
after
the
rotating
screens
before
the
cooling
water
pumps.
The
mussels
in
the
intake
system
have
been
controlled
by
recirculating
the
hot
water
return
back
through
the
off
line
intake
unit.
This
is
done
March
12,
2004
­
Page
18
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38
for
2
hours
at
a
temperature
of
46­
48
°
C
(
115­
118
°
F).
After
the
2
hour
kill
has
been
achieved,
the
discharge
flow
is
sent
back
to
the
main
discharge
channel.
This
system
has
worked
well
for
a
number
of
years
(
for
as
long
the
current
Environmental
Engineer
is
aware)
in
an
environment
of
prolific
mussel
growth.

Unfortunately
retrofitting
OCOGEFs
and
the
seafood
processing
vessels
with
additional
intakes
(
if
required),
cross
over
piping,
and
hot
water
return
is
very
expensive.
This
type
of
solution
is
best
incorporated
in
the
design
phase
of
a
facility.

IV.
Typical
Sea
Water
Intake
Structures
A.
General
Pumping
Arrangement
Descriptions
1.
Caisson
Pumping
Arrangements
A
caisson
(
as
referred
to
here)
is
simply
a
steel
pipe
attached
to
a
fixed
structure
that
extends
from
an
operating
area
down
some
distance
into
the
water.
It
is
used
to
provide
a
protective
shroud
around
another
process
pipe
or
pump
that
is
lowered
into
the
caisson
from
the
operating
area.
Please
refer
to
figure
1
below
for
a
generic
caisson
installation.

A
caisson
to
house
seawater
intake
equipment
is
a
very
common
arrangement
used
by
OCOGEFs.
Typical
equipment
installed
in
the
caisson
may
be
a
simple
suction
pipe,
submersible
pump
and
discharge
pipe
or
a
shaft
driven
borehole/
vertical
turbine
pump
(
please
see
diagrams
below).

All
caisson
arrangements
have
the
similarity
that
seawater
is
drawn
into
a
single
opening
at
the
bottom
of
the
caisson.
Also,
since
the
caisson
typically
houses
the
seawater
pump
and
pipe,
the
caisson
is
typically
large
in
diameter
compared
to
the
seawater
suction/
discharge
pipework.

Generic
Caisson
Arrangement
Caisson
Sea
Level
Sea
Floor
Platform
Structure
Working
Area
March
12,
2004
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Page
19
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38
Various
Submersible
Pump
Sizes
Submersible
Pump
Installed
in
Caisson
Vertical
Turbine
Pump
Vertical
Turbine
Pump
Installation
I
t
must
be
noted
that
there
are
many
other
types
of
pumps
that
may
be
used
inside
a
caisson
but
the
principal
that
the
caisson
is
open
at
the
bottom
remains.

Technologies
Suitable
for
Use
with
a
Caisson
The
most
likely
technologies
to
reduce
impingement
and
entrainment
of
marine
life
in
this
type
of
structure
would
be
passive
intake
screens
or
velocity
caps.
Air
sparges
and/
or
Cu/
Ni
alloys
can
be
used
to
control
bio­
fouling.

Other
technologies
such
as
acoustic
barriers,
electro
barriers
or
intake
location
may
also
be
used.
Furthermore,
keel
cooling
technologies
may
be
possible
to
remove
the
need
to
draw
up
cooling
water.
These
options
would
have
to
be
weighed
in
accordance
with
cost
and
benefit.

2.
Simple
Intake
Pipe
Pumping
Arrangements
A
simple
intake
pipe,
as
the
name
suggests,
is
a
pipe
that
is
open
ended
into
the
water.
A
pump
will
draw
water
up
through
the
pipe
for
distribution
as
required
by
the
process.
These
systems
generally
include
a
strainer
to
protect
the
pump
and,
if
the
pump
is
above
water
level,
a
non­
return
valve
(
foot
valve)
to
help
keep
the
system
primed.
March
12,
2004
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Page
20
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38
Generic
Simple
Pipe
Arrangement
Generic
Simple
Pipe
Intake
System
One
of
the
key
difficulties
with
this
type
of
system
is
that
the
Net
Positive
Suction
Head
(
NPSH)
available
to
the
pump
may
be
close
to
the
NPSH
required
for
the
desired
delivery.
That
is,
most
pumps
have
limitations
on
the
allowable
negative
gauge
pressure
on
the
suction
side
of
the
pump.
If
the
suction
pressure
falls
below
it's
NPSH
required
limit,
cavitation
will
occur
in
the
pump.
The
simple
pipe
intake
is
best
suited
to
situations
where
the
pump
is
close
to
or
below
the
water
level
to
maximise
NPSH
available.

Technologies
Suitable
for
Use
with
a
Simple
Pipe
The
most
likely
technologies
to
reduce
impingement
and
entrainment
of
marine
life
in
this
type
of
structure
would
be
Passive
Intake
Screens
or
Velocity
Caps.
Air
sparges
and/
or
Cu/
Ni
alloys
can
be
used
to
control
bio­
fouling.
A
great
deal
of
care
needs
to
be
taken
with
this
type
of
installation
to
protect
the
NPSH
available
to
the
pump.

Other
technologies
such
as
acoustic
barriers,
electro
barriers
or
intake
location
may
also
be
used.
Certainly
these
technologies
would
be
very
helpful
in
protecting
NPSH
available
to
the
pump.
Furthermore,
keel
cooling
technologies
may
be
possible
to
remove
the
need
to
draw
up
cooling
water
3.
Sea
Chest
Pumping
Arrangements
Sea
chest
is
a
shipping
industry
term
that
refers
to
the
sea
water
intake
structure
of
a
vessel.
A
sea
chest
arrangement
typically
includes
a
grill
(
coarse
screen)
on
the
outside
of
the
vessel,
an
open
pipe
from
grill
to
an
isolation
valve
on
the
inside
of
the
vessel,
a
screen
box
containing
a
fine
screen
and
removable
lid
and
another
isolation
valve
to
the
on
board
pump
header.
Simple
Pipe
Sea
Level
Sea
Floor
Platform
Structure
Working
Area
Pump
Strainer
Foot
Valve
March
12,
2004
­
Page
21
of
38
Generic
Sea
Chest
Arrangement
I
n
addition
to
this,
engine
room
sea
chests
are
normally
installed
in
pairs
(
more
than
a
single
pair
of
intakes
for
larger
vessels)
on
each
side
of
the
vessel
centre
line.
Following
is
a
plan
and
elevation
of
a
sea
chest
installation.

Sea
Chest
Plan
(
from
McAlpine
Marine
Design
Pty
Ltd)

Sea
Chest
Elevation
Pump
Header
External
Coarse
Screen
Screen
Box
with
removable
lid
Isolation
Valves
Vessel
Hull
Fine
Screen
March
12,
2004
­
Page
22
of
38
Photo
of
an
External
Sea
Chest
Screen
Photo
of
an
Internal
Sea
Chest
Screen
Box
The
design
of
sea
chests
for
everything
from
small
fishing
vessels
to
large
bulk
carrier
ships
typically
follows
the
same
principals.
However,
this
may
not
be
true
for
all
MODUs
or
other
OCOGEFs
that
may
use
a
sea
chest
arrangement.

I
nterviews
with
the
designers
of
fishing
and
commercial
vessels
revealed
that
plastic
bags
are
the
primary
concern
for
sea
chests.
A
single
plastic
bag
has
the
potential
to
completely
clog
an
intake
and
result
in
some
serious
mechanical
damage
to
the
engines.
The
intakes
and
grilles
are
consequently
sized
to
limit
the
impingement
of
plastic
bags.
Vessels
that
operate
in
a
stationary
manner
(
such
as
pearl
processors)
use
sea
chests
that
are
twice
the
diameter
of
an
equivalent
vessel
that
is
normally
in
motion
(
refer
to
Appendix
A).
This
design
consideration
has
the
double
benefit
that
it
also
limits
fish
entrainment
and
impingement.

Interviews
with
the
operators/
maintainers
of
sea
chests
on
commercial
vessels
revealed
that
it
is
not
common
for
fish
to
be
drawn
into
the
intake
structures.
The
Big
Lift
vessel
Happy
Buccaneer
operates
stationary
for
long
periods
and
utilizes
plate
type
heat
exchangers.
Any
fish
remnants
passing
through
the
cooling
water
system
would
clog
up
the
heat
exchangers.
This
problem
has
not
been
experienced
by
the
crew
(
refer
to
Appendix
A).
The
only
incidents
that
this
study
found
of
problems
with
fish
in
the
water
intakes
involved
jellyfish
swarms.

Technologies
Suitable
for
Use
with
a
Sea
Chest
A
passive
intake
screen
over
the
opening
in
the
hull
is
the
only
really
practical
physical
barrier
for
this
type
of
intake.
However,
the
use
of
a
passive
intake
screen
on
a
sea
chest
may
be
prone
to
impingement
issues.
The
size
of
the
opening
of
a
sea
chest
into
the
ocean
is
essentially
fixed
as
it
would
be
very
costly
to
expand
(
involving
significant
works
at
a
dry
dock
and
structural
works).
A
passive
screen
March
12,
2004
­
Page
23
of
38
that
has
a
suitably
low
face
velocity
may
therefore
have
to
protrude
outside
the
hull
of
the
vessel.
This
would
have
a
negative
impact
on
the
hydrodynamics
of
the
vessel
and
create
a
catch
point
under
the
waterline.
Alternatively,
the
passive
screen
may
be
used
in
conjunction
with
another
technology
such
as
and
acoustic
or
electro
barrier
to
reduce
impingement.

Keel
Cooling
Technology
is
a
practical
alternative
to
the
drawing
in
of
seawater
for
cooling
purposes.

V.
Typical
OCOGEF
Sea
Water
Intake
Structures
A.
Fixed
Platforms
Image
from
Safety
Projects
International
Inc.

Fixed
platforms
are
by
far
the
most
numerous
OCOGEFs
currently
operating
in
the
OCS.
The
number
of
active
facilities
that
drilling
is
likely
to
occur
is
well
into
the
thousands
(
2381)
(
TDD
2001
6­
4).

There
is
no
limit
to
number
of
different
designs
of
these
structures.
There
may
be
some
generic
similarities
between
designs
of
this
type
of
structure
but
each
structure
is
designed
for
a
very
specific
job
to
be
done
at
a
fixed
location.
As
such,
platforms
may
vary
vastly
in
layout.

Typically,
these
facilities
utilize
caisson
structures
or
simple
pipe
structures
to
draw
seawater
up
from
the
ocean
(
as
per
the
Tetratech
2003
Draft
Oil
and
gas
platform
CWIS
data).
The
technologies
suitable
for
retrofitting
these
intake
structures
include
passive
intake
screens
and
velocity
caps
(
as
noted
above
for
caisson
and
simple
pipe
arrangements).

The
special
considerations
that
need
to
be
accounted
for
when
considering
retrofitting
to
these
structures
are
as
follows:

 
They
may
be
in
very
remote
locations,
 
The
intake
opening
may
be
congested
among
other
structures,
 
Access
to
the
intake
opening
may
be
only
be
achievable
with
the
use
of
special
divers,
 
Installation
of
other
equipment
(
such
as
air
compressors
for
sparge
systems)
may
be
very
difficult
due
to
limited
deck
space,
and,
 
Each
platform
is
an
individual
design.
March
12,
2004
­
Page
24
of
38
B.
Jack­
ups
Image
from
EPA
Web
site
Jack­
up
facilities
are
the
most
numerous
of
the
mobile
OCOGEFs
(
Mobile
Offshore
Drilling
Units
 
MODU)
currently
operating
in
the
OCS.
There
are
in
the
order
of
140
currently
operating
in
the
Gulf
of
Mexico
(
GOM)
(
TDD
2001
6­
4).

There
is
less
variation
in
the
design
of
these
structures
as
they
are
typically
manufactured
by
a
relatively
small
number
of
suppliers.
Furthermore,
they
all
do
a
similar
job.
Jack­
ups
are
designed
to
be
transported
to
various
sites
around
an
oil
field
to
undertake
exploration
and
development
drilling
activities.
When
they
arrive
at
the
desired
location,
their
legs
are
lowered
to
the
sea
floor.
As
such,
they
have
depth
limitations
as
a
function
of
the
length
of
their
legs.

These
facilities
may
use
a
form
of
caisson
structure,
simple
pipe
structure
or
a
sea
chest
arrangement
to
draw
seawater
up
from
the
ocean
(
as
per
the
Tetratech
2003
Draft
Oil
and
gas
platform
CWIS
data).
The
different
intake
designs
are
likely
to
represent
different
solutions
to
the
problem
that
the
vessel
operates
with
variable
leg
length
submerged.
The
technologies
suitable
for
retrofitting
these
intake
structures
need
to
be
confirmed
by
the
designers
of
these
facilities.

The
special
considerations
that
need
to
be
accounted
for
when
considering
retrofitting
to
these
structures
are
as
follows:

 
They
generally
operate
to
very
tight
schedules
that
may
be
very
expensive
to
alter,
 
Access
to
the
intake
opening
may
be
only
achievable
with
the
use
of
special
divers,
and,
 
Installation
of
other
equipment
(
such
as
air
compressors
for
sparge
systems)
may
be
very
difficult
due
to
limited
deck
space
and
payload
limits.
March
12,
2004
­
Page
25
of
38
C.
Semi­
submersibles
Image
from
US
Minerals
Management
Service
(
MMS)
web
page
A
number
of
semi­
submersible
MODU
facilities
operate
in
the
OCS;
in
the
order
of
40
currently
operating
in
the
GOM
(
TDD
2001
6­
4).

Like
jack­
ups,
there
is
limited
variation
to
the
design
of
these
structures
as
they
are
typically
manufactured
by
a
relatively
small
number
of
suppliers
and
they
all
do
a
similar
job.
They
are
designed
to
be
transported
to
various
sites
around
an
oil
field
to
undertake
exploration
and
development
drilling
activities.
When
they
arrive
at
the
desired
location,
they
fill
up
vast
ballast
tanks
with
seawater
for
stability
and
partially
sink
(
hence
the
name
semi­
submersible).

These
facilities
typically
use
a
sea
chest
arrangement
to
draw
seawater
up
from
the
ocean
(
as
per
the
Tetratech
2003
Draft
Oil
and
gas
platform
CWIS
data).
The
technologies
suitable
for
modifying
a
sea
chest
intake
on
a
semi­
submersible
structure
need
to
be
confirmed
by
the
designers
of
these
facilities.

The
special
considerations
that
need
to
be
accounted
for
when
considering
retrofitting
to
these
structures
are
as
follows:

 
They
generally
operate
to
very
tight
schedules
that
may
be
very
expensive
to
alter,
 
Access
to
the
intake
opening
may
be
only
achievable
with
the
use
of
special
divers,
and,
 
Installation
of
other
equipment
(
such
as
air
compressors
for
sparge
systems)
may
be
very
difficult
due
to
limited
deck
space
and
payload
limits.
March
12,
2004
­
Page
26
of
38
D.
Drill
Barges
Image
from
Flexifloat
web
page
A
number
of
drill
barge
MODU
facilities
operate
in
the
OCS;
in
the
order
of
20
currently
operate
in
the
GOM
(
TDD
2001
6­
4).

There
is
no
limit
to
the
number
of
different
possible
designs
of
these
facilities.
Furthermore,
no
group
of
suppliers
that
specialize
in
this
type
of
equipment
has
been
identified.
As
such,
drill
barges
may
vary
vastly
in
fundamental
design
and
layout.
They
are
designed
to
be
transported
(
generally
towed
but
self­
propelled
is
possible)
to
various
sites
around
an
oil
field
to
undertake
exploration
and
development
drilling
activities.

Tetratech
2003
Draft
Oil
and
gas
platform
CWIS
data
does
not
include
any
data
on
Submersible
MODUs.
It
is,
however
a
reasonable
assumption
that
sea
chest
arrangements
or
simple
pipe
inlets
would
be
used
to
draw
in
seawater.
The
technologies
suitable
for
modifying
these
intake
structures
needs
to
be
confirmed
by
the
designers/
operators
of
these
facilities.

The
special
considerations
that
need
to
be
accounted
for
when
considering
retrofitting
to
these
structures
may
include:

 
Tight
operating
schedules
that
may
be
very
expensive
to
alter,
 
Access
to
the
intake
opening
may
be
only
achievable
with
the
use
of
special
divers,
and,
 
Installation
of
other
equipment
(
such
as
air
compressors
for
sparge
systems)
may
be
very
difficult
due
to
limited
deck
space
and
payload
limits.

E.
Submersibles
Image
from
Transocean
Web
Page
March
12,
2004
­
Page
27
of
38
A
limited
number
of
submersible
MODU
facilities
operate
in
the
OCS;
in
the
order
of
6
are
currently
operating
in
the
GOM
(
TDD
2001
6­
4).

Due
to
the
limited
number
of
submersible
MODUS,
there
are
a
limited
number
of
designs
for
these
structures.
Furthermore,
they
must
all
do
a
similar
job.
They
are
designed
to
be
transported
to
various
sites
around
an
oil
field
to
undertake
exploration
and
development
drilling
activities.
When
they
arrive
at
the
desired
location,
they
fill
up
vast
ballast
tanks
with
seawater
for
stability
and
sink
to
the
ocean
floor
(
hence
the
name
submersible).

These
facilities
typically
use
a
sea
chest
arrangement
to
draw
seawater
up
from
the
ocean
(
as
per
the
Tetratech
2003
Draft
Oil
and
gas
platform
CWIS
data).
The
technologies
suitable
for
modifying
a
sea
chest
intake
on
a
semi­
submersible
structure
need
to
be
confirmed
by
the
designers
of
these
facilities.

The
special
considerations
that
need
to
be
accounted
for
when
considering
retrofitting
to
these
structures
are
as
follows:

 
They
generally
operate
to
very
tight
schedules
that
may
be
very
expensive
to
alter,
 
Access
to
the
intake
opening
may
be
only
achievable
with
the
use
of
special
divers,
and,
 
Installation
of
other
equipment
(
such
as
air
compressors
for
sparge
systems)
may
be
very
difficult
due
to
limited
deck
space
and
payload
limits.

F.
Drill
Ships
Image
from
US
Minerals
Management
Service
(
MMS)
web
page
A
limited
number
of
drill
ship
MODU
facilities
operate
in
the
OCS;
in
the
order
of
5
are
currently
operating
in
the
GOM
(
TDD
2001
6­
4).

Drill
ships
may
be
purpose
designed
or
constructed
by
modifying
a
bulk
carrier.
These
facilities
typically
use
a
number
of
sea
chests
to
draw
seawater
up
from
the
ocean
(
as
per
the
Tetratech
2003
Draft
Oil
and
gas
platform
CWIS
data).
These
sea
chests
are
very
likely
to
be
a
conventional
design
(
refer
to
the
generic
sea
chest
arrangement
above).
Therefore,
the
technologies
noted
above
as
suitable
for
a
sea
chest
should
be
suitable
for
use
on
a
drill
ship.
This
needs
to
be
confirmed
by
the
designers/
operators
of
these
vessels.

The
special
considerations
that
need
to
be
accounted
for
when
considering
retrofitting
to
these
structures
are
as
follows:

 
They
generally
operate
to
very
tight
schedules
that
may
be
very
expensive
to
alter,
March
12,
2004
­
Page
28
of
38
 
Access
to
the
intake
opening
may
be
best
achieved
during
routine
dry
dock
maintenance
of
the
vessel,
and,
 
Installation
of
other
equipment
(
such
as
air
compressors
for
sparge
systems)
may
be
very
difficult
due
to
limited
deck
space
and
payload
limits.

VI.
Typical
Seafood
Processing
Vessel
Sea
Water
Intake
Structures
A.
Factory
Trawlers
Image
from
Tetratech
A
large
number
of
Factory
Trawlers
are
likely
to
be
operating
in
the
OCS
at
any
given
time.

I
t
is
reasonable
to
assume
that
the
majority
of
these
vessels
use
a
sea
chest
arrangement
that
resembles
the
generic
system
noted
above
(
refer
to
interviews
with
vessel
designers,
builders
and
operators
in
Appendix
A).
Furthermore,
interviews
with
trawler
designers
and
operators
indicate
that
keel
cooling
is
a
"
standard"
technology
used
by
this
type
of
vessel.
Discussions
with
keel
cooler
manufacturers
have
found
that
keel
cooling
is
a
practical
system
to
retrofit
to
an
existing
vessel.
The
cost
magnitude
of
this
type
of
retrofit
is
unknown.

The
special
considerations
that
need
to
be
accounted
for
when
considering
retrofitting
to
these
structures
are
as
follows:

 
Access
to
the
intake
opening
may
be
best
achieved
during
routine
dry
dock
maintenance
of
the
vessel,
and,
 
Anything
protruding
past
the
hull
at
the
sea
chest
would
create
major
operational
difficulties
(
generally
very
undesirable
due
to
the
ropes
and
nets
used
on
these
vessels).

B.
Floating
Processors
A
number
of
floating
processors
are
known
to
be
operating
in
the
OCS.

Floating
processors
(
also
called
offshore
processors)
are
usually
ships
or
barges
that
have
been
converted
into
floating
fish
processing
factories.
They
rarely
do
any
actual
fishing.
Instead
they
buy
and
process
the
fish
and
shellfish
caught
by
other
boats.
The
also
resupply
the
fishing
boats
with
food
and
fuel.
The
advantage
is
that
the
smaller
vessels
do
not
have
to
return
to
port
to
resupply
and
can
spend
more
time
fishing.
Floating
processors
usually
dock
in
sheltered
bays
near
major
fishing
activities
and
may
remain
for
as
long
as
three
months
at
a
time
(
Tetratech
2003)

It
is
reasonable
to
assume
that
that
majority
of
these
vessels
would
use
a
sea
chest
arrangement
that
resembles
the
generic
system
noted
above.
In
the
case
of
a
converted
barge,
a
simple
intake
pipe
would
also
be
possible.
March
12,
2004
­
Page
29
of
38
As
noted
above,
keel
cooling
is
a
"
standard"
technology
used
by
cooling
circuits
on
trawlers.
A
keel
cooler
manufacturer
indicated
that
keel
cooling
could
be
used
on
a
stationary
vessel.
However,
this
is
likely
to
require
a
significantly
larger
to
achieve
the
same
heat
transfer.
It
may
be
practical
system
to
retrofit
to
an
existing
vessel
but
the
cost
magnitude
of
this
type
of
retrofit
is
unknown.

The
special
considerations
that
need
to
be
accounted
for
when
considering
retrofitting
to
these
structures
are
as
follows:

 
Access
to
the
intake
opening
may
be
best
achieved
during
routine
dry
dock
maintenance
of
the
vessel,
and,
 
Anything
protruding
past
the
hull
at
the
sea
chest
would
create
major
operational
difficulties
(
generally
very
undesirable
due
to
the
ropes
and
nets
used
on
these
vessels).
March
12,
2004
­
Page
30
of
38
REFERENCES
Alevras,
R.
A.
1973.
Status
of
air
bubble
fish
protection
system
at
Indian
Point
Station
on
the
Hudson
River.
pp.
289­
291.
in
Entrainment
and
Intake
Screening
Workshop
held
at
the
Johns
Hopkins
Bibko,
P.
N.,
L.
Wirtenan,
and
P.
E.
Kueser.
1973.
Preliminary
studies
on
the
effects
of
air
bubbles
and
intense
illumination
on
the
swimming
behavior
of
the
striped
bass
(
Morone
saxitalis)
and
the
gizzard
shad
(
Dorosoma
cepedianum).
pp.
293­
304.
in
Entrainment
and
Intake
Screening
Workshop
held
at
the
Johns
Hopkins
University,
Baltimore,
Maryland.

Northeast
Science
and
Technology
(
NEST)
Technical
Report
TR­
031
May
1996:
Mattagami
River
Lake
Sturgeon
Entrainment:
Little
Long
Generating
Facilities.
J
Seyler,
J
Evers,
Dr
S
McKinley,
R
Evans,
G
Prevost,
R
Carson,
D
Phoenix
Fish
Guidance
Systems
Limited
(
FGS):
Designer
and
supplier
of
a
range
of
acoustic
barriers
for
large
industrial
water
intakes.
www.
fish­
guide.
com
Fournier
P.
1983
Passive
Screening
at
Surface
Water
Intakes.
Johnson
Screen
Division.

Fore,
P.
L.
1969.
Responses
of
freshwater
fishes
to
artificial
light.
Ph.
D.
Disser.,
South.
IL.
Univ.,
86pp.
(
cited
from
Hocutt.
1980).

Hocutt,
C.
H.
1980.
Behavioral
barriers
and
guidance
systems.
pp.
183­
205.
In
Hocutt
et
al.
(
ed.)
Power
Plants:
Effects
on
fish
and
shellfish
behavior.
Academic
Press.
New
York.

Lieberman,
J.
T.
and
P.
H.
Muessig.
1978.
Evaluation
of
an
air
bubble
to
mitigate
fish
impingement
at
anelectric
generating
plant.
Estuaries.
1:
129­
132.
Loeffelman,
P.
H.,
J.
H.
Van
Hassel,
and
D.
A.
Klinect.
l991a.
Using
sound
to
divert
fish
from
turbine
intakes.
Hydro
rev.
10(
6):
30­
37.

Patrick,
P.
H.,
R.
S.
McKinley,
and
W.
C.
Micheletti.
1988.
Field
testing
of
behavioral
barriers
for
cooling
water
intake
structures
­
Test
Site
1
­
Pickering
Nuclear
Generating
Station.
pp.
4­
13­
25.
in
Proceedings:
fish
protection
at
steam
and
hydro­
electric
power
plants.
EPRI/
AP­
5663.
Electric
Power
Research
Institute.
Palo
Alto,
CA.

Smith,
K.
A.
1961.
Air­
curtain
fishing
for
marine
sardines.
Comm.
Fish.
Rev.,
23(
3):
1
14.
(
cited
from
Hocutt
1980).

Taft,
E.
P.,
J.
K.
Downing,
and
C.
W.
Sullivan.
1987.
Studies
of
fish
protection
methods
at
hydroelectric
plants.
pp.
512­
521.
in
Waterpower
'
87.

Tetratech
2003
Draft
Oil
and
gas
platform
CWIS
data
Tetratech
2003
Draft
Cooling
Water
use
by
Offshore
Seafood
Processing
Vessels
9
May
2003.

TDD
2001,
United
States
Environmental
Protection
Agency,
Technical
Development
Document
for
the
Final
Regulations
Addressing
Cooling
Water
Intake
Structures
for
New
Facilities
Zweiacker,
P.
J.,
J.
R.
Gaw,
E.
Green,
and
C.
Adams.
1977.
Evaluation
of
air­
bubble
curtain
to
reduce
impingement
at
an
electric
generating
station.
Proceedings
of
the
Thirty­
First
Annual
Conference
Southeastern
Association
of
Fish
and
Wildlife
Agencies.
31:
343­
356.
March
12,
2004
­
Page
31
of
38
Appendix
A
Industry
Representative
Interview
Notes
1/
4/
2003
 
Kwinana
Power
Station
 
Robin
Howarth:
Environmental
Engineer
General
Info:
 
Kwinana
Power
Station
is
a
medium
size
multi
fuel
(
gas,
oil
andcoal)
power
station
that
operates
on
Cockburn
Sound
in
Western
Australia.
 
The
power
station
draws
seawater
from
the
Sound
for
cooling
via
a
submerged
pipe
into
an
onshore
sump.
The
offshore
intake
uses
a
static
screen
(
size
unknown)
to
prevent
entrainment.
Rotating
screens
are
used
to
ensure
any
debris/
fish
is
kept
away
from
the
cooling
water
pumps.
 
There
are
two
identical
seawater
intake
units
(
duty
and
stand­
by).
 
There
is
a
large
supply
of
fish
and
mussel
within
the
Sound
that
create
problems
with
the
power
station
water
supply.
 
The
power
station
has
a
novel
method
for
dealing
with
the
mussel
growths
in
the
intake
system.
It
uses
the
hot
seawater
return
to
prevent
the
mussels
from
forming
in
the
intake
pipe.

Environmental
Engineer's
Comments:
 
Auto
chlorination
(
electrolysis)
is
uses
to
treat
the
water
after
the
rotating
screens
before
the
cooling
pumps.
 
The
mussels
in
the
intake
system
have
been
controlled
by
recirculating
the
hot
water
return
back
through
the
intake
system
of
the
off
line
intake
unit.
This
is
done
for
2
hours
at
a
temperature
of
46­
48
°
C
(
115­
118
°
F).
After
the
2
hour
kill
has
been
achieved,
the
discharge
flow
is
sent
back
to
the
main
discharge
channel.
 
This
system
has
worked
well
for
a
number
of
years
in
an
environment
of
prolific
mussel
growth.

Engineer
Observations
(
Hatch
Associates):
 
A
very
interesting
and
environmental
way
to
keep
mussel
numbers
under
control.
 
This
is
not
likely
to
be
a
practical
method
to
prevent
bio
growth
in
offshore
oil
and
gas
or
fishing
vessel
seawater
intakes
but
it
is
worth
knowing
about.

10/
4/
2003
 
Cargo
Ship
"
Lyndsay
Clarke"
Sample
of
photo's
taken:
March
12,
2004
­
Page
32
of
38
Note
the
jelly
fish
on
the
intake!
General
Info:
 
Captain:
Rumi,
Ship's
Engineer:
Mike.
 
Size:
183m
(
600ft)
x
23m
(
75ft).
36,000
tonne.
 
Engine:
Single
BMW
Direct
Reversible
2
stroke
diesel
 
Two
intakes
on
each
side
of
vessel
("
high"
and
"
low")
 
4
sea
chests
each
with
3ftx3ft
screens
fitted
(
slotted
opening
size
not
known
exactly
but
approx
1.5­
2"
based
on
photos
supplied
by
the
Engineer)
 
2
chests
on
each
side
of
the
vessel
and
connected
by
a
common
header
running
laterally
across
the
ship.
 
There
are
two
strainer
baskets
on
the
common
header
(
one
each
side
of
the
ship).
 
The
sea
chests
were
located
aft
in
the
vessel
on
either
side
of
the
engine
room.
 
The
flow
line
from
the
sea
chests
on
the
outside
of
the
vessel
(
as
viewed
from
the
inside)
would
appear
to
coincide
with
the
flow
approaching
he
propeller.
 
Intake
Peak
flow
rate
(
everything
running):
13400GPM
(~
3ft/
sec
through
1
screen)
 
Typical
Inflow
Rate
(
engine
cooling
+
some
ancillary):
6400GPM
(~
1.5ft/
sec
through
1
screen)

Chief
Engineer's
Comments:
 
Typically
the
strainers
are
emptied
once
every
6
months.
 
The
biggest
problem
with
the
intake
is
seaweed
not
fish.
Apart
from
jellyfish
while
in
port,
there
was
very
little
evidence
in
the
Chief
Engineer's
experience
(
7
years
with
this
ship)
that
fish
were
a
problem
in
the
intake
system.
 
The
engineer
commented
that
the
propeller
and
bow
thrusters
would
be
the
most
likely
source
of
fish
injuries
or
fatalities.

Engineer
Observations
(
Hatch
Associates):
March
12,
2004
­
Page
33
of
38
 
Although
this
is
not
a
fish
processing
or
oil
and
gas
extraction
vessel,
the
configuration
of
the
intake
system
and
the
experience
of
the
people
operating
and
maintaining
it
is
very
useful.
The
intake
structure
currently
sits
between
the
ships
ribs
and
any
increase
in
it's
size
would
require
some
significant
structural
modifications.
Furthermore,
as
the
intake
is
under
the
operating
level,
to
gain
access
to
the
structure
for
upgrade
would
require
the
removal
and
refit
of
a
significant
amount
of
equipment
located
in
the
engine
room.
This
would
be
extremely
time
consuming
and
expensive
to
achieve.
Based
on
the
Chief
Engineers
comments
regarding
the
small
quantity
of
fish
observed
to
be
drawn
into
the
intake
structure,
I
believe
that
any
sea
chest
modification
to
this
vessel
would
not
achieve
anything.
 
The
engineer's
experience
with
the
intake
structure
indicates
that
this
system
does
not
have
an
entrainment
issue.
Impingement
is
not
likely
to
be
an
issue
with
this
intake
while
the
ship
is
in
motion
as
the
flow
past
the
hull
will
be
faster
than
the
flow
into
the
intake.

14/
4/
2003
 
Woodside
Energy
Limited
 
Garry
Bowtell:
Lead
Projects
Engineer
General
Info:
 
Garry
indicated
that
the
Rankin
A
platform
offshore
in
the
Northwest
of
Western
Australia
uses
the
depth
of
the
intake
as
the
primary
fish
deterrent.
He
was
uncertain
of
the
detail
but
indicated
that
he
was
not
aware
of
any
problems
with
this
approach.
 
Garry
suggested
that
we
contact
the
environmental
department
of
Woodside
Energy
to
pursue
this
further.

Engineer
Observations
(
Hatch
Associates):
 
This
looks
to
be
a
very
interesting
approach
but
I
have
had
no
luck
getting
anyone
else
in
Woodside
to
talk
to
me
about
their
intake
technologies.
I
will
ask
the
US
EPA
will
provide
an
introductory
letter
for
me
to
be
able
to
make
more
effective
contact
with
this
company.

16/
4/
2003
 
M
G
Kailis
Pty
Ltd
Fishing
Vessel
Builder
General
Info:
 
MG
Kailis
is
one
of
the
main
fishing
vessel
design
and
fabricators
in
Western
Australia.
 
Kailis
group
also
operates
one
of
the
largest
fishing
vessel
fleets
in
the
state.
 
An
interview
was
held
with
their
Senior
Design
Engineer
Frank
Pensabene.

Design
Engineer
Comments:
 
Fishing
vessels,
such
as
trawlers,
generally
have
sea
chest
arrangement
that
includes
a
screen.
 
Typically
fish
being
drawn
into
the
intake
system
is
not
a
problem.
Frank
indicated
that
this
was
not
a
general
design
consideration
even
though
a
significant
fish
intake
would
damage
the
pumps
and
heat
exchangers
on
board
the
vessel.
 
The
primary
design
criteria
for
seawater
intakes
are
to
prevent
fouling
by
plastic
bags
(
impingement
and
entrainment).
A
single
plastic
bag
can
cause
massive
problems
with
a
vessel's
cooling
water
circuit.
 
On
vessels
that
are
moving
(
like
trawlers)
the
screen
is
sized
to
be
typically
3
times
the
pipe
diameter.
 
On
vessels
that
are
stationary
(
like
pearl
harvesters)
the
screen
is
sized
to
be
typically
6
times
the
pipe
diameter.
 
Following
are
the
details
on
one
pearl
harvesting
vessel
that
Frank
had
details
on
hand:
March
12,
2004
­
Page
34
of
38

Vessel
Type:
Multi
Purpose
Pearling
­
monohull

Size:
35.5m
(
116.5ft)
x
9.1m
(
29.9ft),
450
tonnes.


Apart
from
engine
cooling
water,
there
are
11
service
water
pumps
each
with
their
own
sea
chest.


Service
Water
Pumps:
Centrifugal
pumps
with
100NB
(
4")
suction,
7.5kW
(
10HP),
30
l/
sec
(
475.5GPM)


Sea
chests
for
each
pump
have
a
Diameter
of
600mm
(
2ft)
and
a
resultant
through
screen
velocity
of
0.139m/
s
(
0.46
ft/
sec).
Hole
size
=
3/
8".

Engineer
Observations
(
Hatch
Associates):
 
It
appears
to
me
that
the
primary
design
criterion
for
plastic
bags
has
the
dual
purpose
of
protecting
the
seawater
intakes
from
fish
impingement
and
entrainment.
This
is
very
good
news
and
the
US
industry
may
also
use
this
design
criteria.
Further
investigations
into
the
design
of
fishing
vessels
are
required
(
next
interview
to
be
arranged
with
Lombardo's).

23/
4/
2003
 
Walkers
Clean
Water
Company
Pty
Ltd
General
Info:
 
Walkers
Clean
Water
is
the
largest
supplier
of
water
intake
systems
in
Western
Australia
(
and
an
agent
for
Johnson
Screens
among
others).
 
An
interview
was
held
with
their
Manager
Kevin
Lampard.

Manager's
Comments:
 
The
Johnson
Range
of
screens
is
the
most
common
type
of
protection
used
for
industrial
water
intake
applications.
 
The
most
common
reason
that
screens
are
used
on
a
seawater
intake
is
to
protect
mechanical
equipment
rather
than
fish;
however,
the
Johnson
screens
are
designed
to
prevent
fish
mortality
(
many
years
of
RandD
into
this
field).
As
a
consequence,
industries
that
use
this
type
of
screen
are
also
helping
to
protect
the
environment.
 
Kevin
was
not
aware
of
any
ultrasonic,
strobe
or
other
technologies
that
were
used
to
warn
off
fish.
Compressed
air
is
frequently
used
to
purge
screens
but
there
was
no
evidence/
history
that
it
is
used
to
scare
away
fish.
 
Kevin
was
able
to
show
me
a
copy
of
a
specification
that
he
is
currently
biding
on.
This
was
for
a
seawater
intake
that
fish
mortality
was
a
design
consideration.
The
design
included
a
caisson
with
a
Tee
screen
at
the
bottom.
The
interesting
thing
is
that
this
is
the
type
of
modification
that
is
likely
to
work
for
an
offshore
platform.
The
caisson
has
a
vertical
turbine
pump
inside
that
would
be
very
similar
to
many
offshore
platforms
(
flow
rate
=
800
l/
s
=
12680
GPM).

Engineer
Observations
(
Hatch
Associates):
 
Kevin
invited
me
to
forage
through
his
files
on
intake
systems.
During
my
search,
I
found
a
report
(
dated
1982)
that
included
Velocity
caps
as
a
form
of
fish
protection.
Wisconsin
Power
and
Light
may
have
installed
a
velocity
cap
system
in
Lake
Michigan
in
1982
(
according
to
the
report).

25/
4/
2003
 
Big
Lift
Ship
"
Happy
Buccaneer"
Sample
of
photo's
taken:
March
12,
2004
­
Page
35
of
38
General
Info:
 
Ship's
Engineer:
Evo.
 
Size:
145.9m
(
478.7ft)
x
28.3m
(
92.8ft).
16,341
tonne
Gross,
4902
tonne
Net.
 
Engines:
2
x
5000HP
Souzer
(
main
engines),
2
x
800kW
(
1070HP)
Daihatsu
(
auxiliary
engines).
 
Single
intakes
on
each
side
of
vessel
(
Port
side
"
high"
starboard
side
"
low")
 
Sea
chest
plus
strainer
 
Header
size
500NB
 
Sea
chest
screen
1000x500
with
5mm
holes/
openings
(
assume
50%
opening).
Strainer
has
same
size
holes.
 
Max
intake
flow
rate
=
2000tonne
per
hour
(
8800GPM)
with
all
3
ballast
pumps
running
(
600kl/
hr
ea)
=>
face
velocity
at
sea
chest
=
0.9m/
s
(
3ft/
sec)
bulk,
1.8m/
s
(
5ft/
sec)
local
at
screen
opening.
 
Typical
inflow
rate
less
than
500
tonne/
hr
=>
face
velocity
at
sea
chest
=
0.225m/
s
(
0.75t/
sec)
bulk,
0.45m/
s
(
1.5ft/
sec)
local
at
screen
opening.
 
Once
ballast
is
taken
on
for
a
cargo,
it
is
kept
for
the
entire
time
that
the
cargo
is
held
on
board
and
moved
from
hold
to
hold
to
adjust
during
the
big
lift
operations.

Ship's
Engineer
Comments:
 
Have
not
found
any
evidence
that
fish
are
drawn
into
the
intake
structure
during
normal
conditions.
If
there
were
a
problem
it
would
be
obvious
since
the
heat
exchangers
are
plate
type
and
any
"
bio­
mush"
would
clog
up
the
plates.
 
The
strainers
are
cleaned
out
once
every
4
months
and
there
is
no
evidence
of
fish
debris
in
the
screen.
 
The
only
time
that
they
had
a
fish
intake
problem
was
during
operation
in
a
jellyfish
swarm.
This
was
an
isolated
incident
and
caused
all
sorts
of
problems
to
the
operation
of
the
ship
(
Similar
experience
as
had
the
Lindsay
Clarke
ships
engineer).
 
Have
found
crabs
living
in
the
intake
pipework
on
rare
occasions.
The
interesting
thing
is
that
they
were
larger
than
the
screen
holes.
This
suggests
that
they
had
lived
for
some
time
in
the
intake
system
(
long
enough
to
grow
larger
than
the
screen).

Engineer
Observations
(
Hatch
Associates):
 
Modifications
to
the
existing
intake
system
would
be
extremely
expensive.
The
sea
chests
are
integral
to
the
hull
and
would
require
major
structural
re­
enforcement
if
made
larger.
Extended
dry
dock
time
would
be
required
for
this
operation.
 
The
engineer's
experience
with
the
intake
structure
indicates
that
this
system
does
not
have
an
entrainment
issue.
Impingement
is
not
likely
to
be
an
issue
with
this
intake
while
the
ship
is
in
motion
as
the
flow
past
the
hull
will
be
faster
than
the
flow
into
the
intake.
However,
while
the
ship
is
stationary
or
in
port,
impingement
may
occur.
The
portion
of
time
that
this
may
be
a
problem
would
be
if
the
ship
were
drawing
in
ballast
at
max
flow
rate
in
preparation
for
cargo.
Filling
the
ballast
tanks
would
take
a
few
hours
(~
4
hours
at
max
fill
rate)
from
empty
and
represent
a
very
small
portion
of
the
operating
time
of
the
vessel.
 
Overall,
I
would
say
that
there
would
be
very
little
benefit
gained
from
modifying
the
intake
structure
of
this
vessel.
There
may
be
some
benefit
with
other
technologies
with
regard
fish
scaring
devices
but
these
have
not
yet
been
identified.

5/
5/
2003
 
Western
Australian
(
WA)
Fisheries
Department
­
Dan
Machin:
Project
Officer
General
Info:
 
Dan
Machin
is
a
"
Special
Projects
Officer"
for
the
WA
fisheries
Department
and
has
the
most
exposure
to
the
front
end
of
unusual
or
novel
fisheries
projects.
As
such,
he
was
interviewed
to
ascertain
if
there
were
any
technologies
other
than
screens
that
have
been
used
to
keep
fish
away
from
intakes
and
other
structures.
March
12,
2004
­
Page
36
of
38
 
Dan
said
that
the
most
common
devices
used
were
screen
(
as
per
the
Johnson
style
of
screen)
or
barrier
nets.
He
was
not
aware
of
any
other
technology
being
used
commercially.
 
Dan
did
however
know
of
a
research
project
that
may
be
under
way
at
the
Curtin
University
in
WA
that
was
looking
at
a
sonic
barrier
to
at
keep
predatory
fish
away
from
commercial
mussel
lines.
 
Dan
was
asked
about
air
or
bubble
curtains
but
did
not
think
that
that
technology
was
in
use
within
the
industry
in
WA.
Engineer
Observations
(
Hatch
Associates):
 
Dan
had
a
keen
interest
in
trying
to
help
us
out
but,
apart
from
the
lead
to
Curtin
University,
was
unable
to
point
us
at
any
new
technologies
that
may
be
helpful.
 
Dan
took
my
contact
details
and
will
let
me
know
if
he
comes
across
anything
that
we
might
find
interesting.

6/
5/
2003
 
Curtin
University
of
Technology
 
Rob
McCauley:
Research
Leader
General
Info:
 
Rob
is
the
primary
contact
for
the
sonic
fish
barriers
to
be
used
for
the
mussel
industry.
 
Unfortunately,
funding
for
this
study
was
not
approved
and
it
has
gone
no
further
than
concept.
 
Rob
indicated
that
sonic
barriers
may
be
able
to
scare
away
some
fish
some
of
the
time
but
he
was
not
aware
of
any
way
to
make
it
work
for
all
fish
all
(
or
most)
of
the
time.
 
Rob
said
that
there
may
be
some
research
being
done
in
German
University
but
was
unable
to
give
us
further
contact
details.
Engineer
Observations
(
Hatch
Associates):
 
It
is
disappointing
that
the
trail
has
gone
cold
but
it
points
to
the
fact
that
there
is
very
little
technology
available
for
keeping
fish
away
from
intake
structures
other
than
what
we
already
know
about.

12/
5/
2003
 
Shine
Fisheries
 
Kim
Head:
Fleet
Supervisor
General
Info:
 
Shine
fisheries
is
one
of
the
larger
fishing
companies
in
WA.
 
Kim
indicated
that
plastic
bags
were
the
primary
cause
of
problems
with
seawater
intakes.
Kim
confirmed
Prank
Pensabene's
comments
(
MG
Kailis)
regarding
the
plastic
bag
issue
as
the
primary
design
criteria
for
their
intakes.
Also,
Kim
quoted
a
screen
size
of
3/
8"
opening.
 
Kim
indicated
that
he
had
seen
no
evidence
of
fish
being
drawn
into
the
strainer,
pump
of
heat
exchangers
(
shell
and
tube).
He
said
that
if
they
were
he
would
expect
some
maintenance
issues
with
this
equipment.
 
Kim
indicated
within
their
fleet
of
vessels,
their
most
common
vessel
is
a
25m
(
82ft)
trawler/
processor.
The
engines
are
cooled
using
keel
cooling
(
no
sea
water
requirement).
They
have
sea
water
intakes
for
two
primary
purposes:
1.
Condenser
cooling
for
their
refrigeration
and
2.
Deck
service/
wash
down
water.
Each
of
these
systems
draw
approximately
200l/
min
(
76,000gal/
day).
The
condenser
seawater
pump
runs
24hr/
day
7day/
week
in
port
or
not.
 
Kim
indicated
that
the
trawler
may
be
stationary
(
on
anchor)
in
the
open
ocean
and
running
their
service
pumps
up
to
50%
of
the
time.
For
example,
when
they
are
fishing
prawns,
the
catch
is
only
taken
at
night
and
the
vessel
will
wait
on
anchor
in
the
fishing
zone
during
the
day.
Engineer
Observations
(
Hatch
Associates):
 
This
is
very
useful
information.
Need
to
find
more
out
about
commercial
coolers/
chillers
and
their
seawater
intake/
cooling
requirements.
Also,
the
quantity
of
water
used
appears
to
be
small
in
comparison
to
what
may
be
used
to
cool
typical
March
12,
2004
­
Page
37
of
38
engines.
A
typical
flow
rate
of
between
75,000
and
150,000
Gal
per
day
is
significantly
less
than
the
2MGD
limit
required.
However,
these
vessels
are
not
very
big
(
only
82ft)

14/
5/
2003
 
Tenix
 
Victor:
Project
Engineer
Sample
of
photo's
taken
and
images
provided:
Rescue
vessel
info:

Impounded
Fishing
Vessel:

General
Info:
 
Tenix
is
one
of
the
major
ship
building
companies
in
Western
Australia.
At
the
time
of
my
visit
there
were
two
35m
(
115ft)
search
and
rescue
vessels
under
construction,
on
55m
(
180ft)
vessel
complete,
A
Collins
Class
Submarine
on
dry
dock
for
maintenance
and
an
impounded
fishing
vessel
on
the
slipway.
 
Unfortunately,
I
was
not
allowed
on
board
or
to
take
any
photographs
of
the
submarine
(
it
is
one
of
a
new
fleet
built
diesel
 
electric
for
Australia's
Navy).
The
engineer
who
was
guiding
me
around
the
facility
indicated
that
the
sea
chest
arrangements
were
exactly
the
same
configuration
as
on
other
commercial
vessels.
Interestingly,
there
were
no
external
grills
on
the
sea
chest
inlets
(
straight
through
pipes).
The
engineer
had
also
served
on
one
of
these
March
12,
2004
­
Page
38
of
38
vessels
and
indicated
that
he
was
not
aware
of
any
problems
with
fish
being
sucked
into
the
intakes
(
except
jellyfish).
 
Victor
took
me
though
the
rescue
boats
being
fabricated
(
photo's
above).
Victor
told
me
that
they
use
essentially
the
same
sea
chest
intake
arrangement
on
all
vessels.
 
The
flow
rates
through
grille
are
variable
depending
on
the
demand
on
board
the
ship.
The
"
Rule
of
Thumb"
used
by
Victor
is
to
ensure
that
the
open
area
of
the
intake
is
at
leat
the
same
open
area
of
all
of
the
services
that
it
supplies
(
i.
e.,
pump
suction
diameters).
In
practice,
both
sea
chests
are
operated
in
parallel.
For
the
35m
rescue
vessels,
the
design
intake
volume
was
100kl/
hr
(
630,000
GAL/
Day)
primarily
for
engine
cooling.
The
intake
open
area
is
approximately
0.05m2
(
after
taking
the
grill
into
account)
giving
an
intake
velocity
of
0.5m/
s
(
1.6ft/
sec)
on
1
intake
or
0.25
(
0.8ft/
sec)
with
both
intakes
running.
 
Engine
specifications
for
the
35m
rescue
vessels
are:
2
off
Main
Engines
CAT
3508
(
1050kW
=
1410HP
each),
1
off
Loiter
Engine
CAT
3408
(
65kW
=
540HP),
2
off
CAT
Gen
Sets
(
65kW
=
90HP
each)
 
Following
is
a
design
that
Tenix
have
used
to
protect
the
rescue
boat's
seawater
intake
from
environments
of
excessive
seaweed.
The
resultant
open
area
is
nearly
twice
that
of
the
uncovered
opening
(
therefore,
the
intake
velocity
is
approximately
halved).
Also,
the
mesh
opening
is
significantly
smaller
than
the
grill
opening
to
prevent
the
seaweed
entering
the
intake.
Victor's
comments
were
that
this
was
not
a
common
addition
(
he
was
not
aware
of
this
type
of
solution
being
used
elsewhere)
and
he
was
unsure
that
it
would
remain
attached
for
long.
The
intention
is
for
it
to
be
install
by
a
diver
just
prior
to
entering
the
water
with
a
weed
problem
and
remove
it
again
as
soon
as
the
area
has
been
passed.

Engineer
Observations
(
Hatch
Associates):
 
This
is
very
useful
information.
The
fact
sea
chests
apparently
all
abide
by
the
same
general
configuration
is
very
helpful.
Furthermore,
this
appears
to
be
a
tried
and
true
approach
that
avoids
contamination
form
debris
and
fish.
 
This
sea
chest
cover
may
be
useful
when
ships
are
passing
areas
of
high
fish
densities.
