PRELIMINARY REGULATOR? DEVELOPMENT
SECTION 316(B) OF IHE CLEAN WATER ACT
BACKGROUND PAPER NUMBER 3:
COOLING WATER INTAKE TECHNOLOGIES
April 4, 1994
Prepared for?
U.S. Environmental Protection Agency
Office of Wastewater Enforcement and Compliance
Permits Division
401 M Street S.W.
Washington, D.C. 20460
Prepared by:
Science Applications International Corporation
7600-A Leesburg Pike
Falls Church, VA 22043
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TABLE OF CONTENTS
INTRODUCTION AND METHODOLOGY 1-1
COOLING WATER INTAKE CONSIDERATIONS 2-1
2.1 Cooling Water Intake Flows and Sources 2-1
23. Impacts and Problems Associated with Cooling Water Withdrawal from
Surface Waters 2-1
2.2.1 Entiainnient and/or ^"ipinggtncnt 2-2
2.2.2 Biofouling and Corrosion 2-2
2.3 Mitigation Techniques 2-2
2.3.1 Location of Cooling Water Intakes 2-3
2.3.2 Cooling Water Flow Reduction Techniques 2-3
2.3.3 Cooling Water Intake Technologies 2-5
3. IK'AKE TECHNOLOGY REVIEW 3-1
3.1 Intake Screen Systems 3-1
3.1.1 Summary of Findings: Intake Screen Systems 3-2
3.1.2 Conclusions: Intake Screen Systems 3-5
3.2 Passive Intake Systems (Physical Exclusion Devices) 3-6
3.2.1 Summary of Findings: Passive Intake Systems 3-6
3.2.2 Conclusions: Passive Intake Systems 3-7
3.3 Fish Diversion and/or Avoidance Systems 3-8
3.3.1 Summary of Findings: Fish Diversion and/or Avoidance
Systems 3-8
3.3.2 Conclusions: Fish Diversion and/or Avoidance Systems 3-11
4. SUMMARY AND NEXT STEPS 4-1
1
APPENDIX A A-l
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LIST OF TABLES
Table 3-1. Cooling Water Intake Technologies by System Category (with
spading fact sheet number) 3-2
VUUlrtHMJ
11
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1. INTRODUCTION AND METHODOLOGY
The purpose of this paper is to present the finding* of an initial examination of cooling
water intake technologies currently used or being tested for minimising the loss of aquatic
organisms due to gntnrinniynt and impingement effects. The paper also provides a brief
discussion of flow reduction techniques and intake siting considerations. The information is
intended to be used by the U.S. Environmental Protection Agency (EPA) as baseline data for
evaluating the range of future regulatory options under Section 316(0) of the Clean Water Act
(CWA).
Background Paper 2, entitled •Cooling Water Use for Selected U.S. Industries and
Summary of Selected EPA Regional and State Section 316(b) Activities", described the cooling
water uses and flows for the steam electric power generation industry and for various
facturing industries. Paper 2 indicated mat the majority of high flow water use industries
steam electric power plants) use private intake water supplies from fresh, brackish,
and marine sourctiV To supply these intake flows, steam electric power plants and other
industrial facilities ^k&t construct some type of intake structure capable of handling the large
flows of intake wateV. These structures are designed to allow the free flow of water, but must
ai«> ensure that organic and inorganic debris does not enter the system and cause damage to
pumps, equipment, or cooling system condensers and/or heat exchangers. In accordance with
Section 316(b), these intake structures must also be located, designed, and constructed utilizing
the best technology available to mjnimjre adverse environmental impact.
To identify technologies used at cooling water intakes, the available literature was
reviewed. Most of the literature available is related to the technologies used by the steam
electric industry. This industry withdraws the bulk of the cooling water used in the United
Stales. However, information on technologies used at other types of water intakes, such as those
for desalinization plants, water supply systems, hydroelectric facilities, and irrigation systems,
was also reviewed. It should be noted that the literature reviewed for this initial examination
does not represent an exhaustive list of all the available information on each technology.
Because of time and resource constraints, the literature search was limited to those resources that
could be identified and obtained within a reasonable period of time.
This paper rfjynw* the impacts of high flow cooling water intakes and the location,
design and operational technologies that have been developed to mitigate these impacts. Section
2 of this paper presents background information regarding cooling water intake and use, effects
of cooling water withdrawal, and techniques for minimizing these effects. Section 3 categorizes
intake control technologies into system types and presents a listing of the various technologies
identified as a result of this research effort. Section 3 continues by discussing the operation and
use of the intake technologies investigated. Section 4 summarizes all of the technology types
reviewed and offers some recommendations for additional study. Finally, Appendix A contains
detail^ fact sheets for each of the technologies identified. The fact sheets provide pertinent
information on the frequency of use, design considerations, field testing results, and advantages
and limitations for each technology reviewed.
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2. COOLING WATER INTAKE CONSIDERATIONS
This section discusses cooling water intake practices at steam electric power plants and
Other i«^igtrial fnattflfacfliyffjg farili^i^ Initially f a hfjgf ciitntnafy pf pooling wafl»f f"tato» fl«uic
and sources is provided along with a ^yH1?****1 of the potential problems and impacts
with the withdrawal of large flows of cooling waters from surface water sources. Finally, mis
section disnissfff the types of mitigation tpch'pquffs that may be considered to nhiimi***- impacts
to aquatic organisms at cooling water intakes.
2.1 Cooling Water Intake Flows and Sources
The findings in Background Paper 2 indicate mat the 2,417 power generation units of the
U.S. steam electric industry withdrew approximately 303,350 million gallons per day (MGD)
in 1991. This equates to an avenge of approximately 12S.S MGD per generation unit. Of this
total, approximately 208,300 MGD (68.7 percent) were withdrawn from a fresh water source,
50,000 MGD (16.5 percent) WCK, withdrawn from a saline water source, and 42,800 MGD (14. 1
percent) were withdrawn fror^c brackish water source. The remaining 0.7 percent was
withdrawn from groundwater, -n-unicipal effluent, and municipal water supplies (EH, 1993).
Non-steam electric generation facilities used a total intake (for all uses) of approximately
28,600 MGD and had a total cooling water intake flow of approximately 16,000 MGD in 1982.
Of *h*g total, the four industrial categories withdrawing the highest flows of cooling water
reported an average withdrawal of 4.86 MGD per facility. These four industrial categories also
reported mat an average of 70 to 90 percent of their total flows were from private surface water
systems (USDOC, 1983).
Based on these findings, it is evident mat nearly all steam electric feHii^^ and the
majority of other industrial facilities withdrawing large flows of pooling water use surface water
sources (fresh, saline or brackish).
23 Imparts and Problems Associated with Cooling Water Withdrawal from Surface
Waters
Inherent in the use of surface waters as a source, is the need for the construction of an
intake structure into mat water source. Because of the large flows of water withdrawn at cooling
water intake structures, organic and inorganic matter present in the water source may be
inadvertently drawn into the intake. Aquatic organisms may be injured and/or killed through
entrainment or impingement if drawn into the cooling water intakes. In addition, intake of these
materials may cause biofouling and corrosion and can seriously damage pumps and equipment
at steam electric power plants anj other industrial facilities that tair*» jn large flows of cooling
water. Cooling water intake structures, therefore, should be designed to minimize the intake of
unwanted
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2.2.1 IfotrMiimMif antUar
The process of withdrawing surface waters from fresh, marine, or brackish sources for
use as pooling water may result hi the entrap""*"* (i.e., drawing in) of small gq"a**g organisms,
such as fish eggs and larvae, and the inmingement (Le., trapping and holding) of larger
s, such as fish and shellfish, against the outer part the cooling water intake structure.
In addition, entrauunent and/or impingement can cause injury and/or mortality to these
"Entrain tnynt
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2.3.1 Location of CffoBng Water Tntalr*>*
The first approach that can be taken to mfrMini«e adverse aquatic impacts from cooling
water intakes is the location of the cooling water intake structure. There are three principal
related to intake location: *«fe»v*> operation, construction activities, and
GUYUVIU
For the purposes of this paper, only die «™tigatinn practices related to intake
operation will be discussed.
To properly characterize the site, a facility nay need to peifuiiu an extensive
geographical and ecological survey in the vicinity of the proposed site. The survey data arc then
used to determine potential impacts that may be caused to important wildlife and aquatic
breeding, nursery, feeding, and/or migration areas. Furthermore, the survey data might enable
determinations to be made with regard to concentrations of aquatic life within specific and
proposed siting areas. In addition to ecological considerations, the final selection of an intake
location is dependent on physical characteristics of the proposed water body as well as hydraulic
2HQ
A principal factor determining thu^ . sntial impact of an intake location is the water
source. As stated earlier in Section 2. 1, thf:\,Sst common water sources are fresh water rivers,
fresh water lakes and reservoirs, estuaries, and1 oceans. Each of these sources has unique flow
characteristics that must be considered in the location of the intake structure. Intake structure
design and siting considerations related to the water source include, direction and rate of stream
flow, flooding, ice and ice flows, tidal influences, thermal stratification, salinity and currents
(EPA, 1973).
Other intake siting considerations include the proximity of the effluent discharge point,
distance from the shoreline, the water depth of the intake structure, and the proximity of
sensitive biological communities. ^*arh of these factors should be flTff*s**d to determine possible
environmental iprcparfo and the intake location established to m*™ifriwt the impact.
2*3.2 Cooling Water Flow Reduction Techniques
The second approach that can be taken to minimize the adverse aqira**r impacts of
cooling water intake structures is to reduce the rate and degree to which cooling water is
withdrawn. Reductions in cooling water intake flow will reduce entrainment and impingement
impacts. Once-through cooling systems have been found to cause higher rates of entrainment
frfcausp of the considerable and continuous amount of water used by these systems as compared
to the flows used by closed-cycle systems.
Steam electric power plants may be designed to use cooling water in a once-through,
system a closed-cycle system, or a combination of the two. Once-through cooling systems
withdraw water from a replenishable source (e.g., river, estuary or ocean), run the water
through condensers, and then discharge the withdrawn water without recirculation.
Closed-cycle systems extract cooling water from a natural source, or from a plant's own
dedicated cooling pond, or some other source. Unlike the once-through system, cooling water
in a closed-cycle system is recirculated. Closed-cycle systems generally utilize some type of
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cooling tower to return the cooling water to a nominal temperature which will allow it to be used
repeatedly. Only water necessary to replace evaporative loss is then continuously withdrawn
from the water source. These closed-cycle systems typically use only two to three percent of
the cooling water flow mat is required by once-through systems.
As noted above, most closed-cycle systems utilize cooling towers to return the heated
cooling water to a lower temperature. Cooling towers can be defined as enclosed devices for
the evaporative cooling of water by contact with air. Although multiple types of cooling towers
exist, the basic premise far all types is similar. To be cooled, water is usually sprayed into air
passing through the tower, and, as evaporation occurs, the temperature of the water decreases.
To aid in evaporation, the water falls onto a series of decks or baffles within the tower which
act to increase the surface area of the water exposed to evaporation. The cooled water men falls
to a catch basin or pond for potential reuse, or is discharged back to the original water bcry.
The resultant airsteam is directed through drift eliminators prior to being vented to die
atmosphere (Stanford, 1970).
;-agh cooling towers are typics. -sfened to as closed-loop systems, water lest to
evaporati^/aiid blowdown mtist be consider.. As water is lost thorough evaporation, dissolved
minerals are concentrated and total dissolved solids (TDS) concentrations begin to rire,
Excessive TDS concentrations have detrimental impacts on cooling systems; thus, water (with
high concentrations of TDS) is constantly released from the system as blowdown. Additional
water (make-up water) is men taken into the system to provide dilution. The amount of
blowdown and evaporative loss varies considerably depending on the type of cooling tower used
and the operational parameters; however, make-up water (i.e., raw water intake) requirements
are far lower for these closed-cycle systems than for once-through cooling systems (Plant
Engineering, 1992).
In practice, either natural or mechanical draft cooling towers are standard. Natural draft
towers have no mechanical device to create airflow through the tower and are usually applied
in very small or very large applications. A common natural draft tower is the hyperbolic
cooling tower often utilized at steam electric power plants. These towers, which may be up to
300 feet tall, are capable of cooling approximately 50,000 to 150,000 gallons per minute of
flow, allow air to enter through an open ring around the bottom and flow up through packing
«"*!f"3l over which warm water is distributed. The air is released through the chimney and the
cooled water rains into a pond below the tower for collection and reuse (Plant Engineering,
1989). Although c^yfoig varies with the size and materials sfifcfrd, typical costs asy"***"*1 with
the construction of a hyperbolic cooling tower range from S3 to $6 million (Mariey, 1994).
For intermediate-sized water cooling applications with throughputs ranging from 20,000
to 50,000 gpm, mechanically induced or forced draft cooling towers are typically employed.
In addition, for some larger appi*?3tioins, cross-flow inditctyf draft cooling towers may be TiVfd
In each of these systems, air is forced or drawn by fans through cooling cells containing the
water flow (Foust, 1980). As with the hyperbolic systems, costs vary widely depending on size
and materials. However, for most individual cells, costs range from $100,000 to $200,000
(Mariey, 1994).
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Environmental factors such as composition of the blowdown water, discharge steam
plume effects, discharge temperature and noise generation must be considered in the design and
construction of cooling towers. As water is circulated through a cooling system, it is typically
treated to inhibit scale formation and biofouling. Bfcauy of chgntica* additives,
dissolved scatet and increased temperatures, the blowdown (effluent) from cooling towers may
adversely affect amfr*CTt receiving water quality. In addition, steam plumes from large cooling
towers may create fogging, icing, and/or drift, which can deposit water or minerals on adjacent
areas (Power, 1992).
2.3.3 Cooling Water Intake Technologies
The third apppffiicn th** can be employed to tnttiitmae adverse aq'"^ impacts is to
require an fa**aiia*rgn of an effective ««ftK«g water *ntaigg» technology that will reduce fish loss
due to entrainment and impingement. Currently, many cooling water intake structures employ
some type of technology but, in most cases, these technologies have been installed only to
prevent debris from entering the cooling water system; they were not usually installed to prevent
adverse environmental impacts from occurring. The i*'-;t common intake devices used by the
steam electric industry, as well as other industries, ir* * .'- a design with front-end trash racks
(usually consisting of fixed bars) to prevent large debr>- Tiom entering the system, followed by
single-entry, single-exit vertical traveling screens (conventional traveling screens) to prevent
smaller debris from clogging the condenser tubes. These devices are by far the most common
The remainder of this paper will provide a review of intake technologies that have been
developed to minimize environmental impact. The review includes all intake technologies
currently used at steam electric power plants (U.S. and foreign), as well as any other
technologies under development mat may have die potential to mfrimiiMt fish losses. Since the
1970s, when there was a regulatory initiative to tninimfaf environmental impacts at cooling
water fofiikffSi many additional technologies (or fnodificfltiotis to existing technologies) were
tested and installed, particularly at ******] electric power plants.
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3. INTAKE TECHNOLOGY REVIEW
A total of 25 intake trrhnfl1r>gies were identified in the literature as being appropriate
ftt install at <*ftft]it>g *"g*y *"firi» etroetOTBe tn minimfn* Mvimnmental impacts. Each technology
was Pffurr-1*^ and reviewed to evalnate its application at cooling water intake structures and
to affffs its potential and efficacy to tnitnmiaa advene environmental «««pag»y The 25 intake
technologies were «-fa««fi*»< as faffing under one of three system categories. The technologies
were iH*nrifiiid as being: (1) an intake screen system, (2) a passive intake system, or (3) a fish
diversion or avoidance system.
Table 3-1 presents technologies classified under each of the three categories. The general
purpose of these technologies, in addition to the frequency of their use and performance, is
summarized in the text below. Fact sheets supplying additional detaU regarding each technology
are provided in Appendix A. The fact sheets furnish information in the following areas: general
technology description, testing facility** and/or facilities using the technology,
research/operational findings, design considerations, advantages &d limitations of using the
technology, and supporting references. Additional references are i ' provided for some of the
technologies. These additional references were not reviewed during is research effort because
of time and budget constraints; however, these references should be considered for review at a
date so th?f the efficiency of die technologies is thoroughly evaluated.
3.1 Intake Screen Systems
The technologies rfawfi«< as intake screen systems in Table 3-1 are mainly those devices
mat screen debris mechanically as compared to the passive intake systems where little or no
activity is required. The intake screen systems category includes technologi
currently in use at steam electric generating units. The system category also includes alternative
screen technologies, which are not currently in use at U.S. steam electric facilities. Although
the intake screen system technologies were not designed with fish protection in mind, they may
provide a certain level of protection. They are, therefore, presented so that their use may be
considered under subsequent Section 316(b) regulatory activities.
3.1.1 Summary of Findings: Intake Screen Systems
Singla-Fntrv. Single-Exit Vertical Traveling Screens: These conventional traveling
screens are the most widely used screening device for removal of debris. They are used by 60
percent of an the steam electric generating units in the United States (EEI, 1993). Their use
is based on the collection and removal concept, high screenwell velocities, entrapment areas in
the screenwell, and the handling of impinged fish as debris. These screens are most commonly
ayyviatprf with devices that cause entrainment and impingement impacts (Fritz, 1980). Some
major United States steam electric power plants have experienced problems in debris handling
when these screens have been used (Richards, 1988).
Modified Traveling Screens (Ristroph Screens): These are conventional traveling screens
modified so mat fish impinged on the screens can be removed with minimal stress and mortality.
An »«gntiai feature of such screens is continuous operation during periods where fish are being
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Table 3-1. Cooling Water Intake Technologies by System Category
(with corresponding fact sheet number)
•f; -V,'
_
.INTAKE COKXB0L, *
'XcuuflO
(Coovmtionil)
Modified Vertical Twvcfing
(RamqA Screens)
TaveUng
-a(Do«lFlow)
HcflXQtttU TlBVBIE."
Screens
10
11
Vertical Drum
Systems
12
Wedge-Wire
13
Penontod Pipec
14
Radial Wefls (Ramey CoDeaon)
15
Porous Dikes
16
Artificial Filter Beds
17
IS
Velocity Cap
19
Fish Banter Nets
20
21
Etectrical Barriers
TJght
Water Jet
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impinged compared to conventional traveling screens, which operate on an intermittent basis.
Most of the impingement performance studies conducted for these screens at a number of steam
electric power plants indicate a high initial survival rate for impinged fish (EPRI, 1989, Fritz,
1980). However, limited information was obtained during this research effort regarding the
long-term survival of impinged fish on these screens. Since modified screens have been shown
to lower fish impingement and mortality over conventional screens, the modified screens have
been installed at several facilities as best available intake technology (EPRI, 1989). Eight
currently operating, once-through steam Hff'lf'r- generating units use mis technology at their
water j"«gto»« (EEI, 1993).
SinPte"FntfV- Single-Brit Inclined THYBJing SffTP^^' This technology uses conventional
traveling screens but places them at an angle to the faea«M^g flow. The angle placement
improves the overall effectiveness of the screen since fish tend to avoid the screen's face. A fish
bypass facility with independently induced flow must be provided with mis technology to direct
fish away from the intake device. Tj"litari""g include higher costs than die conventional
traveling screen and a need far stable water elevation at the intake structure (ASCE, 1982).
Single-Entry. Double-Brit Vertical Traveling Screens: In this screen'Xf'X-.inown as the
a), water enters the center of the screen and passes from the ins&j to the outside
of the smTTM^f surface. The screen surface is theoretically double the y«» of a conventional,
vertical traveling screen. This type of stieen, which was developed in Europe almost 30 yean
ago, is currently in operation at only a few major U.S. steam electric plants. The velocity of
flow entering between the screen races is usually high, which leads to increased impingement
and entrainment (Richards, 1988). Such screens can contribute to higher impingement because
the required screen well can act as an entrapment device. From a fish protection standpoint, this
screen does not offer any advantage over the single-entry, single-exit vertical traveling screen.
Single-Exit Vertical Traveling Screens fP*^J J*ivar Screens!: In the double-
entry, single-exit (dual flow) vertical traveling screens, water enters from both me ascending and
^gy-onHiiig sides of the screens and discharges from the downstream end between the faces while
the upstream end is blocked off. The unit is turned so that the approach flow is parallel to the
faces of the screen. Several utilities have recently completed installation, or are planning to
install, dual flow screens because of their debris handling capabilities (EPRI, 1989). The
performance evaluation of dual flow screens available from several in-plant studies does not
indicate any real increase in impingement survival over conventional vertical traveling screens,
especially when incorporated at an intake designed with low approach velocity (EPRI, 1989).
Data from the F^ Power Statistics Database indicate mat nine once-through steam electric
ating units currently use this technology.
Horizontal Traveling Screens: Horizontal traveling screens are continuously moving
screens that span the intake area in water source being screened. The screens rotate horizontally
in the waterway with the upstream face placed at an angle to the flaw. This placement guides
fish in a manner similar to louvers and angled screen systems. Horizontal traveling screens form
a complete physical barrier and have a high fish diversion efficiency in that they also release
impinged fish into a bypass without passing the air-water interface. However, the requirement
of continuous operation, at much higher speeds than the conventional vertical traveling screens,
has created mechanical problems that have not yet been resolved (ASCE, 1982). Because of this
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rational limitation, the Miff"6 are not currently manufactured. Application of this type of
screen to a large industrial intake would require extensive and costly research (EPA, 1976).
Fine \iieth Scr****** Mmm**jd_on_TrayeKpp SCI*PM; Fine tn**^1 iMipdtff "iffliPtfd on
traveling screens are used to exclude eggs, larvae, and juvenile farms of fish from intakes.
These screens rely on gentle impingement of organisms on the screen surface or retention of
larvae within the screens. The success of an installation using fine mesh screens is contingent
on the application of satisfactory *****""»£ and recovery *»•«***•• to allow the safe return of
impinged organisms to the aquatic environment (Pagano et aL, 1977; Shanna, 1978). In situ
studies on the use of fine mesh on conventional traveling screens and modified traveling screens
have indicated that these mesh v •*"•« reduce entzainmenL However* these II^MHS have not
been demonstrated to be effective for reducing mortality or mtnrinmrnt losses (EPRI, 1989).
which ars widely iTffd outside tfag
United States, are screens placed on large evolving wheels. The screens are placed witn then-
longitudinal axes horizontal across the inakc channel. They are considered more ^ffiHenf in
debris removal and more reliable titan conv^fmal traveiing screens. The main advantages of
drum screens are their simplicity, fewer mcv^S parts man in conventional traveling screens,
their ease of nutiiQ^nanog, and the elimination -o? any possibility of debns carryover. The main
disadvantage of horizontal drum screens is their capital cost The screens themselves are usually
less costly than the conventional traveling screens, but the cost of the screen structures is much
larger. The total differential costs are $821,000 (1982 dollars) in favor of die conventional
traveling screens (Richards, 1988). Drum screens are not currently used at U.S. steam electric
plants. There is little evidence to indicate that these screens offer any fish protection advantage
over the conventional traveling screens (ASCE, 1982).
Pniirj Screens: The vertical revolving drum ff Tfii technology CO^T^T** of a
screen placed on a vertical revolving drum, which is located across an intake opening in front
of the pumps. This arrangement operates well under conditions of fluctuating water levels.
Vertical drum screens are not used at U.S. power plants. They have been used for fish
diversion in irrigation canals and in British steam electric stations for protection of salmonids
with variable success (Eicher, 1974). Since larger types have not been developed, their
reliability is unknown (ASCE, 1982).
Rotating Disk Screen: The face of the rotating Hidr is covered by nresfr at right ftpgi^f
to the water channel. The disk rotates around a horizontal axis, bringing the dirty screen face
above water where high pressure sprays wash the debris into a trough. This screen is only
suitable tor relatively small flows and small water level variations. The rotating diyV screen is
not currently used at U.S. steam electric plants. This device has a minimum number of moving
parts and, thus, is inexpensive to buy and maintain. However, the high probability of fish
impingement, the need of high pressure sprays to remove fish and debris, and the need of very
large screen structures to limit screen approach velocities ™?fap it unattractive for usf at cooling
water intakes. Such a screen has no advantage over other common screens from a fish
protection point of view (EPA, 1976; ASCE, 1982).
Fixed Screens! The most common type of fixed screen is the vertically installed device
placed in front of the intake pumps. The screens, generally mounted in a frame, are installed
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in vertical tracks on the intake channel walls and are usually lifted out of the water for cleaning.
Their use is limited to intake locations where suspended debris is negligible. Most of the fixed
Kirmy are *««*gM**1 at y"*»n steam plrrtric ptant* The major limitations of these scrcejis are
that operators must be available at all times to maintain the screens. Long impingement times
between Homing periods may result in total mortality of fish. Data from the EH Power
Statistics Database jp5ft«*» that 13 once-through steam electric units and 31 closed-cycle steam
electric '""** currently in operation in the United States use mis technology.
3.1.2 Conctasions: Intake Screen Systems
The main finding with regard to intake screen systems is mat they are limited in their
abilities to «««»"«»> adverse aquatic impact In <•«*. conventional traveling screens (the most
widely used screening device at U.S. steam electric plants) and most of the other types of
traveling sereens have been installed mainly for their debris handling capabilities. In addition,
the conventional traveling screens have not even been proved to be reliable for the removal of
debris at U.S. ftff1" electric plant intakes. In
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3.2 Passive Intake Systems (Physical Exclusion Devices)
Passive intake systems are those devices that screen-out debris and biota with little or no
mechanical activity required. Most of these systems are based on achieving very low withdrawal
velocities at the scppffning pnyfe* so t*M>f organisms will avoid the intake. Highlights of the
important elements for each passive itita^ift device are summarized below.
3.2.1 Summary of Findings: Fusfoe Ta>tnfc* Systems
Wedpe-Wire Screens! Wedge-wire screens are mainly H^giwH to reduce entrainmentof
fish eggs and larvae by physical rxclusinn and by exploiting hydrodynamics. Physical exclusion
occurs when the mesh size of the screen is smaller than the organisms susceptible to
HyttTooymmiic exclusion icsults fioin xsjuotcosnGC ox & lovy* tfarouEu*slot velocity
which, because r~ ^e screen's cylindncal configuration, is quickly ««««pat«*i thereby allowing
organisms to esc* .ie flow field. In situ and laboratory studies have shown that impingement
is virtually elimu. 3d and mat entrainment is considerably reduced when wedge-wire screens
are used (Hanson, :/78; Weisberg et aL, 1984; Heuer a^Tomljanovitch, 1978; Lifton, 1979;
Delmarva Power and Light, 1982; and Weisberg et aLtTl^Q). This device also offers some
advantage in debris removal (Richards, 1988). Howev&Cit is presently limited to relatively
small flow withdrawals such as make-up water for closed-cycle cooling systems. Data from the
EEI Power Statistics Database indicate that a total of five closed-cycle steam electric generating
units use wedge-wire screens at their intake structure (EEI, 1993).
Perforated Pipes; Perforated pipes draw water through slots in a cylindrical section placed
in the waterway. The term •perforated" is applied to round perforations and elongated slots.
Clogging, frazil ice formation, biofouling and removal of debris limits this technology to small
flow withdrawals. These devices have been used at locations requiring small amounts of water
such as make-up water However, experience at steam electric plants is very limited (Sharma,
1978).
WfflliT - :- -^ w*M* a*» rfeurfnpaH in th» yamy. T"anfKT 8S CCTlVCTtJOP?! well* This
intake consists of a veracal pump caisson, which is sunk below the water table near the surface
water body (e.g., river). Several perforated collector screen pipes (radial wells) are then jacked
out through wall ports into the surrounding porous aquifer. Radial well intakes, long
represented by the Ranney Collector, have a long history of successful performance and offer
maximum protection to aquatic organisms of all sizes. (EPA, 1976; ASCE, 1982). One main
limitation is mat radial wells are only suitable where there is a porous aquifer. This
consideration, and the ajsreiatgd costs of pumps and a large piping network, currently limit the
radial wells for once-through application (Mussalli et aL 1980). Data from the EEI Power
Statistics Database indicate that two closed-cycle steam electric generating units in the United
States currently use radial wells (EEI, 1993).
Porous Dikes: Porous dikes ar.- srs resembling a breakwater surrounding a cooling
water intake. The core of the dike cc: .» of cobble or gravel, whi.h permits free passage of
water. The dike acts both as a physi- _ and behavioral :-*mer 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 dikes come from clogging by debris and silt,
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ice build-up and frazil ice, and fouling by fflff^iffllf"" of fish and plant life. The porous dike
technology is still being developed, and its use is actually limited to small flow intakes. Data
from the i«'m Power Statistics Database indicate ft*?f two once-through steam electric yy-"*"!^
unity in the United States currently use mis technology (EH, 1993).
Artificial pfltgf gcds; Artificial filter beds ntflize a prepared granular filter material to
prf«gnt entrance of *"* «*•*
system does not entrain or impinge aquatic organisms. The system uses physically and
chemically «*»M* non-biodegradable materials for its filtering system. The system is buried 5
to 10 meters from the shoreline and is covered with 10 to 90 crntimrtm of site sand. The
system reportedly uses wave motion to prevent dogging and does not require backwash or
routine maintenance. The system is constructed in modular form and can be constructed to meet
widely varying flow H»manHe (Elarbash, 1991b). Many details regarding construction and
performance were unavailable because of proprietary constraints. Because of the limited
information available, a fact sheet was not developed for mis technology.
3.2.2 Cone Unions; Passive Intake Systems
The main findings for passive intake systems are that available technologies mat
effectively reduce fish *yg* and larvae entrainment are extremely limited In fact, from all of
the passive intake system technologies reviewed, only the radial wells (Raimey Collectors) offer
an effective protection to aquatic organisms of all sizes and provide a degree of screening mat
far exceeds the requirements for cooling water supplies. However, their major limitation is that
the radial wells are only suitable where mere is a porous aquifer. The other limitation is mat
for larger cooling water intakes, the cost of radial wells is considerably greater than that required
The other alternative that appears to offer a potentially effective means of reducing fish
losses is the wedge-wire screen. Testing of wedge-wire screens has demonstrated that fish
impingement is virtually »J«mnia*«H and that entrainment of fish eggs and larvae is reduced.
However, limitations due the physical size of the screening device restrict the application of
wedge-wire screens to closed-cycle make-up or other small flows.
Testing of porous dikes has revealed that this technology is effective in excluding juvenile
and adult fish. The major problems associated with porous dikes are clogging by debris and silt,
ice build-up and frazil ice, and fouling by colonization of fish and plant life. The technology
of the porus dikes is still being developed, and its use is actually limited to small flow intakes.
3-7
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In general, the physical size is the limiting factor of most passive systems, thus requiring
the clustering of a number of screening units. Siltation, biofouling, and frazil ice also limit
areas where passive intake systems can be used. In addition, most of the research for the
reduction of «mqinment has concentzated on the intake of relatively small quantities of water,
in the range of 28 to 56 MGD, typical of the make-up water supply of large coaling water
systems and typical also of nuclear service water systems (Richards, 1977).
Finally, «»*™ia* to the ffarffag* for intake scieeu systems, very little wade is being
conducted or sponsored by utilities to mitigate entrainment and/or impingement through the use
of passive systems at ****K«g water intake structures. This ntnatfcm mggestt that most
generating units are in compliance with the biological conditions contained in their operating
jits (EPRI, 1989).
3.3 Fish Diversion and/or Avoidance Systi .a
Fish diversion and/or avoidance devices are also called behavioral barisrs. These
devices are «*«^efl<*H to GUB advantage of the natural behavioral patr- 7:5 offish so that die fish
will not enter an intake structure. Fish diversion devices either guL^^i'h away from an intake
structure or guide 6sh into a bypass system so that the fish are direct^ a,' physically taken away
from the intake. An example of a fish diversion device includes the louver. Avoidance devices,
on the other hand, are used to make the intake unattractive to fish so that they will avoid the
area of the intake altogether. Avoidance devices include sound barriers, for example. These
devices create sounds mat the fish do not like and will avoid. Unlike the screening and physical
exclusion devices d?ywwd above, behavioral barriers are employed to specifically Vrr ^ish and
other motile organisms from entering the intake system. Like the technologies disnissnri above,
these devices are not always employed to protect fish and organisms but may be used to protect
the equipment at the facility which may get fouled and require more maintenance if fish are
allowed to enter the intake. Important elements of each of the fish diversion and/or avoidance
devices are summariTgd below.
33.1 Summary of Findings: Fish Diversion and/or Avoidance Systems
A summary for each faitf"* fiyh diversion and avoidance technology that are already in
use at U.S. steam electric plants or have the potential to be used at cooling water intake facilities
is presented below. A brief description of each technology is provided, as well as the frequency
of use at U.S. steam electric plants and any pertinent information on the technology's
performance for the protection of aquatic organisms. The frequency of use is based on
information from the "^gf Power Statistics Database and from other available literature.
: Louver barriers consist of a series of vertical panels placed at a 90 degree angle
to the direction of water flow (Hadderingh, 1979). The placement of the louver panels provides
both a change hi the flow direction and velocity mat fish tend to avoid. The angles and flow
velociti^: of the louvers create a current parallel to - • face of the louvers that carries fish away
from ths intake and into a fish bypass system. The: . •» of barriers have been very successful
and have been installed at numerous irrigation it. js, water diversion projects, and steam
electric and hydroelectric facilities. The EEI Powsr Statistics Database does not identify any
steam electric facilities specifically using this technology. This does not necessarily mean that
3-8
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these systems are not used. It could Tn"nn t**at the information cffllfctfuii surveys used to
data for the EEI system did not specifically address fish protection devices.
Velocity Cm: A velocity cap is used on vertical intakes mat are located offshore. The
velocity cap is a cover placed over an intake. Hie cap, in turn, converts vertical flow into
horizontal flow at the entrance of the intake. The device works on the premise that fish will
avoid rapid changes in horizontal flow. Velocity caps have been installed at many offshore
"Hav»f and have been successful in decreasing the impingement of fish. Analysis of the **-**-'
Power Statistics Database indicates that 18 steam rirciiic generating units, representing both
once-through and closed-cycle systems, use velocity caps. Nine of the 18 units use the velocity
cap in conjunction with traveling scfrfns, and two use the cap win fixed screens. Velocity caps
have demonstrated good performance for the protection of aquatic organisms.
Fish barrier nets are large mesh nets placed in front of the entrance
to an intake structure. A&esh of different sizes is used. flependinp on the species that are nresent
site. The barrier nets may function as both a screening device and a deterrent to
Die fish and other orBamsms. Fish barrier nets have been used at numerous facilities ano lend
themselves to ^tita^f*c where the y*8**1"1^ migration of fif*r and other organisms requires fish
diversion fr^are** for only specific times of the year. The EEI Power Statistics Database
reports that five steam electric facilitirs use barrier nets '»|"*«¥"*faE a combined total of 10
units. One facility is listed as using them seasonally. All of the facilities that reported the use
of barrier nets have once-through cooling systems.
Air Bubble Barriers: Air bubble barriers (sometimes called "air curtains" or "bubble
screens") consist of an air header with jets arranged to provide a continuous curtain of air
bubbles over a cross sectional area. The general purpose of air bubble barriers is to repel
schools of fish mat may attempt to pass through the barrier into the cooling water intake. It is
not known whether any facilities are currently using air bubble barriers; however, this
technology has undergone testing at several (approximately 13) steam electric facilities and
laboratories. In general, the results of these evaluations indicate that air bubble barriers have
limited effectiveness as fish deterrent barriers. The effectiveness of mis technology is limited
by several factors including temporal and spatial variability of fish species, water temperature,
light intensity, and water velocity.
Electrical Barriers: Electrical barriers or electric screens consist of a series of immersed >
electrodes and ground wires, which generate an electric field. An electrical shock is produced
when fish or other organisms pass through the field; this, in turn, promotes fish avoidance of
the area. Fri«*Mi» information on the study and USB of electrical barriers indicates that, in
general, electrical barriers do not provide the performance, consistency, or the reliability that
is needed to divert fish and other organisms away from cooling water intake structures.
Research has shown mat this technology is best used for fish that migrate upstream, such as
ya)mfln^ and that can be carried away from the barrier if stunned. In many cases, electrical
barriers have been abandoned as a viable option. Data in Die F^PT Power Statistics Database
show that four facilities use electrical screens: the Mount Tom Facility in Massachusetts, the ML
Hibbard Facility in Minnesota, Connecticut Yankee in Connecticut, and the Michigan City
Facility in Indiana (used in conjunction with air bubble screens) (EEI, 1993).
3-9
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IiigtltBaTTim; Light barriers consist of controlled application of strobe lights or mercury
vapor lights to luxe fish away from ««K«g water intakes or to deflect their natural migration
patterns. This technology is based on research that has shown that some fish avoid light
However, because it is known that some species ate attracted by light, it is generally accepted
that the effectiveness of light barriers is spedes-dependenr, Although this is an inexpensive
technology to JPT*8*1*. the spfrtfy distrihgtiop and ***** response at a, pagt!fftl*af 1M|^t*?n to select the optimum Atrign Apparently, no hght Imnigis
are currently in use as fisfr **f lui"dl " a "**«tifi*d MfcmSe device that pmdiieee ir;»h amplitude,
low frequency sounds to exclude fish. Closely related devices include "f? ''^zones' and
•fishpulsers' (also called •hammers11). The fishdnme produces a wider li-^ge of sound
frequencies and amplitudes than the popper. The fishpulser produces a repetitive sharp
hammering sound of low frequency and high amplitude. In general, however, studies have
shown that these instruments have limited effectiveness in the field.
A recent development, the "Fishstarue System,* is an acoustical fish barrier developed
by Sonalysts, Inc. This device depends on sophisticated sound patterns generated on a site-
specific basis for target fish sprcict. Several research projects indicate that the Fishstartle
System may be a viable technology to reduce entrainment and impingement of fish at cooling
Cable and Chain panJffTir This technology consists of barriers of cables or chains that
are suspended vertically across the front of a cooling water intake. These systems are designed
to take advantage of fish behavior, mat is, of fish tendency to avoid objects moving through
water (Ray et al., 1976). Conclusions of most of the testing conducted to date indicate that
cable and chain barriers show little promise as a technology for diverting fish at cooling water
intakes. No ffrciijtiey in the **>•' Power Statistics Database reported using cable and chafa
barriers.
Water Jet Cumins; Water jet curtains typically consist of a row of vertical pipes, fitted
with evenly spaced jet nozzles, that are then placed hi front of a cooling water intake. The jets
produce a curtain of high pressure water, which is intended to deter fish from entering me intake
area. Water jet curtains have not been used in many actual applications to date. Testing has
not revealed the efficiency of the technology to be appropriate for use alone to divert fish from
cooling water intakes. However, the technology may be used in conjunction with other
technologies to provide an efficient fish diversion system. No faculties in the EH Power
Statistics Database reported using water jet curtains.
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nuve flfiQ* Kadfcl fatahe; A r"™^**1 intake structure has been developed by
Systems of Libya and M&S Systems International of Malta; this systems is reportedly
"virtually invisible to suspended matter, fish and ffaflpq1' sand." This system utilizes a 360
degree radial intake structure mat provides equipotential intake velocity increases as water
approaches the structure. The intake structure also incorporates a louver system within the
hrad to guide figh to a return flow conduit (Elarbash, 1991a). Bfcauy of the proprietary
nature of the system, detailed construction and performance data were not available; thus a tact
sheet was not developed.
3.3.2 Conclusions: Fish Diversion and/or Avoidance Systems
The main finding relative to fish diversion and/or avoidance systems is mat none of the
corresponding **;**<*"?** protect organisms and/or fish that are non-motile or in early life
stages. In addition, because fish diversion and avoidance devices rely on the behavioral
characteristics of fish, the effectiveness and performance of the devices is species-specific.
Therefore, site-specific testing is required in most cases where these devices are to be used. As
a result, modification of the technology to be used may be required.
Many of the fish diversion and avoidance devices are appropriate for seasonal
cntrM"n*ent problems in fa* they provide flexibility to be used during certain times of the year.
For example, barrier nets may be put in place during certain times of the year when fish are
migrating past the intake structure.
Louvers and velocity caps have been proved effective in diverting fish away from intakes
at numerous farfifrieg. Velocity caps are used almost exclusively for offshore intake facilities.
Louvers are often used hi conjunction with other intake technologies such as screens and fish
handling devices. Water jet curtains and cable and chain barriers have not been as successful
as the other technologies.
Barrier nets and electrical barriers are effective with certain applications. Electrical
barriers are effective for upstream migrating fish. If such fish are stunned by the electric shock,
they are carried away from the intake. Electrical barriers, however, are not appropriate for
downstream migrating fish. If such fish are stunned, they are carried with the flow into the
intake. Barrier nets are effective if the fish to be diverted are of similar size.
Air bubble barriers, light barriers, and conventional sound barrier technologies have
as effective fish diversion and avoidance devices. Held applications of air bubble
barriers have generally been unsuccessful and inconsistent Light barriers have proved to be
ineffective in some cases because these devices actually attract certain species of fish; some
sound barrier technologies have demonstrated limited success in the field because some species
to the sound patterns.
3-11
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Society of Civil Engineers. Task CffHimitt?? on Fish-handling of Tn*aV» Structures
of I^E Committee of Hydraulic -fom^UHSk Design of Water Intake Structures far Fish
ASCE, New York, NY, 1982.
"Cooling Towers." Plant Engineering. VoL 46, No 12, July 9, 1992, p. 73.
Delmarva EcolOFr^ Laboratory. Eeoj|Qgi«i1 Studies of the Nanticokg River anj
Vol n. Profile Wire Studies. Report to Delmarva Power wf Tjght Company. 1980.
Mirsky, G.R., Jean-Pierre Libert and Kathy Bryant. •Praignmg Cooling Towers to
Accommodate the Environment" Power. VoL 136, No. 5, p. 95.
Eicfaer, GJ., "Adaptation of Hydro Fish Facilities to Steam-Electric Stations." In
Workshop on Entrainment and Intake Screening. FJprtric Power Research Institute, RP-49,
1974, pp. 199-203.
F^T Pnwer Stan'sfies Patahay. Pi'cpdipd by the Utility Data Tti
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Hanson, B.N., W.H. Bason, B.E. Beitz and K.E. Charles. "A Practical Intake Screen Which
Substantially Reduces die Entxainment and Impingement of Early Life Stages of Fish." In
Fourth National Workshop on Entrainment and Impingement. L.D. Jensen (Editor). F^'flgifal
Analysts, Inc., Melville, NY. Chicago, December 1977, pp 393-407.
Heuer, J.H., and D.A. Tomljanovitch. 'A Study on the Protection of Fish Larvae at Water
Tntai^Bt Using Wedge-Wire Screening. " In IrtffV* Delusion Systems For Power Plant Cooling
Water Intakes. R.K. Sharmer and J.B. Palmer (Editors). Argorme National Lab., Argorme,
IL, February 1978, pp. 169-194.
Lifio&,W.S. "Biological Asp«*« of Semen Testing on the St. Johns River, Patella, Florida,'
In Pp<«iYC ft"**" T"**1^ Workshop. Johnson Division UOP Inc., St. Paul, MN. 1979.
Marley Cooling Tower Company. Personal Qmurumication with Pricing Representative.
Mission, KS. February 23, 1994.
Mussalli, Y.G., EJ*. Taft m, and J. Larsen. "Offshore Water Intakes Designated to Protect
Fish." In Journal of the Hydraulics Division. Proceedings of the America Society of Civil
Engineers. Vol. 106, No Hyll, November 1980, pp. 1885-1901.
Pagano R., and W.H.B. Smith. Rflmit TVelonments " Teehirimie^ ffi Pm^gt Aquatic
Organisms at the In^tes SttfiinriElffft™ Power Plants. MITRE Technical Report 7671.
November 1977.
Ray, S.S., R.L. Snipes, ***4 D.A. Tomljanovich. A State-of-the-Art Report on
Technologies. Prepared for Office of Energy, Minerals, and Industry, Office of Research and
Development U.S. Environmental Protection Agency, Washington, D.C. by the Tennessee
Valley Authority. EPA 600/7-76-020. October 1976.
Richards, R.T. "Present Engineering Limitauons to the Protection of Fish at Water Intakes.*
In Fourth National Workshop on Bitrahiment and Impingement. L.D. Jensen (Editor).
Ecological Analysts, Inc., Melville, NY. Chicago, December 1977. pp. 415-424.
Richards, R.T. Alternative Water Screening tor TTiermal Power Plants. ASCE Journal of
Hydraulics Engineering, Vol 114, No. 6, June 1988, pp. 578-597.
Shanna, R.K., "A Synthesis of Views Presented at die Workshop.* In Lflp^ Fw'vrff"
Systems For Power Piqnt Cooling Watjgr Jpfaipes. San Diego, CA, February 1978, pp. 235-
237.
Stanford, William Cooling Towers: Principles and Practice1! A Practical Guide to Cooling
Tower Selection and Operation. 2nd Edition. Birmingham, AL, Carter Thermal Engineering,
.Ltd., 1970.
USDOC. 1982 Census of Manufactures — Volume 1. U.S. Department of Commerce, Bureau
of the Census. 1983.
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USEPA PcveloDTnent Poeiiincnt for Best Technology Available for the Location. Design.
Construction, and Capacity of Cooling Water Intafe Structures for MJnjjnJTfog, Adverse
Environmental Impact U.S. Environmental Protection Agency, Effluent Guidelines Division,
Office of Water and Hazardous Materials. April 1976.
USEPA. Development Document for PronoM^BesUjBgfanotegy Available for Minimizing
Adverse ^MV'TtHlinSlttI TlTOBC* °^ Cooling Water InQhC Structures. U.S. Environmental
Protection Agency, fffinmnt Guidelines Division, OfiBce of Water and Hazardous Materials.
1973.
UzieUMaxyS. "Entzaininent and Imprngement at Cooling Water Intakes." Literature Review.
Journal Water Pollution Control Federation. 52 (6) (1980): 1616-1630.
Weisberg, S.B., F. Jacobs, W.H. Burton, and R.N. ROSS. Report on Preliminary Studies Using
the Wedge Wire Screen Model Intake Facility. Prepared for State of Maryland, Power Plant
Siting Program. Prepared by Martin Marietta Environmental Center, Baltimore, MD, 1983.
Wrisberfe, S.B., W.H. Burton, E.A. Ross, and F. Jacobs. The Effects of Screen Slot Size.
Scr**^n Diameter, and Through-Slot Velocity on Fntrainment of Fffi]flTjt|C Ichthvoplankton
Through Wedge-Wins Screens. Martin Marietta Environmental Studies, Columbia MD, August
1984.
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APPENDIX A
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INTAKE SCREENING SYSTEMS
x j£JFACT SHEET NO. 1
SINGLE-ENTRY, SINGLE-EXIT
VERTICAL TRAVELING SCREENS
(CONVENTIONAL TRAVELING SCREENS)
The single-entry, single-exit vertical traveling screens (conventional traveling screens) consist
of screen panels mounted on an endless belt; the belt rotates through the water vertically. The
consists of the screen, the drive mechanism, ***** the spray cleaning system.
Most
ventional traveling screens are fitted with 3/8 inch mesh, which screens out and
debris from dogging the pump and the condenser tubes. The screen mesh is usually
supplied in individual removable panels referred to as " baskets" or "trays."
The screen washing system consists of a line of spray nozzles operating at a relatively high
pressure of 80 to 120 pounds per square inch (psi). The screens typically rotate at a single
speed. The screens are rotated either at predetermined intervals or when a predetermined
differential pressure is reached across the screens, based on the amount of debris in the intake
waters.
Because of the intermittent operation of the conventional traveling screens, fish can become
impinged against the screens and eventually die during the extended period of time while the
screens are stationary. When the screens are rotated, the fish are removed from the water and
subjected to a high pressure spray; during mis process, the fish may nil back into the water
and become reimpinged or damaged (EPA, 1976; Pagano et al., 1977).
Conventional Traveling Screen (EPA, 1976)
A-l
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• The conventional traveling screens are the most common screening device currently used
at steam electric power plants. Sixty percent of all facilities use this technology at their
intake structures (EH, 1993).
RESEARCH/OPERATION FINDINGS:
• The conventional single-entry single screen is the most widely-used screening technology
among steam electric power plants (Fritz, 1980).
DESIGN CONSIDERATIONS:
• The screens are designed to withstand a differential pressure across men- face of 4 to 8 feet
of water.
• The recommended 1™****** water velocity through the screen is about 2.5 feet per second
(ft/sec). At or below mis velocity, fish entrainment and impingement are negligible (ASCE,
1982).
• The screens normally travel at one speed (10 to 12 feet per minute) or two speeds (2.5 to 3
feet per minute and 10 to 12 feet per minute). These speeds can be increased to handle
heavy debris loads.
ADVANTAGES:
• Conventional traveling screens are a proven off-the-shelf technology that is readily
available.
LIMITATIONS:
• Impingement is a major problem of the conventional traveling screen technology.
ASCE. Design of Water Intake Structures for Fish Protection. American Society of Civil
Engineers. New York, NY. 1982.
KK1 Power Statistics Database. Prepared by die Utility Data Institute for the Edison Electric
Institute. Washington, DC. 1993.
Fritz, E.S. Cooling Water In^Ve Screening Devices Used to Reduce Entrainment and
Impingement. Topical Briefs: Fish and Wildlife Resources and Electric Power Generation, No. 9.
1980.
Pagano R., ***** W.H.B. Smith. Recent Developments in Techniques to Protect Aquatic Organisms
at the Water Inta^Bj fff Steam-Electric Power Plants. Prepared for Electriche de France. MITRE
Technical Report 7671. November 1977.
A-2
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U.S. EPA. Development Document for B«t Technology A^ilflfrlf ^or ^*e Location. Design.
and Capacity of Cooling Water Iptalre StnmrVtiiiiniizing Adverse
Environmental Impact. U.S. Environmental Protection Agency, Effluent Guidelines Division,
Office of Water and Hazardous Materials. April 1976.
A-3
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INTAKE SCREENING SYSTEMS
FACT SHEET NO. 2 \
MODIFIED VERTICAL TRAVELING
SCREENS
DESCRIPTION:
Modified vertical traveling screens are ennvaiitinmai traveling screens fitted with a collection
"bucket" beneath the screen panel. This intake screening system is also called a bucket
screen, Ristroph screen, or a Sorry Type screen. The screens are modified to achieve
ry of impinged fish by maintaining mem in water while they are lifted to a
release point. The buckets run along the entire width of the screen panels and retain water
while in upward motion. At the uppermost point of travel, water drams from the bucket but
impinged organisms and debris are retained in the screen panel by a deflector plate. Two
material removal systems are provided. The first uses low-pressure spray mat gently washes
fish into a recovery trough. The second system uses the typical high-pressure spray that blasts
debris into a second trough. An gssCTt»?i feature of this screening device is its continuous
elation, which keeps impingement times relatively short (Richards, 1977; Mussalli, 1977;
et al., 1977; EPA, 1976).
Modified Vertical Traveling Screens (White et al., 1976)
A-4
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
Facilities that have tested die screens include Virginia Electric Power Company's Surry Power
Station (White et al.v 1976) (the screens have been in operation since 1974); Dairyland Power
Cooperative's Madgett Generating Station hi Alma, Wisconsin; Consolidated Edison Company
of New York's Indian Point Nuclear Generating Station Unit 2; New York State and Electric
Company's Somerset Generating Station (the screens are fitted with 1 milliinftrT (mm) mesh);
the Orange and Rockland Utility's Bowline Point Generating Station (King et al., 1977); the
Central Hudson Gas and Electric Corporation's Roseton and Danskammer Generating Stations
(King et al., 1977); and the Hanford Generating Plant on die Columbia River (Page et al.,
1975; Fritz, 1980).
RESEARCH/OPERATION FINDINGS;
Modified traveling screens have been shown to have good potential for alleviating
frnpjfigymgut mortality (EPRI, 1989). However, limited information is avaflac :9 on long-term
survival of imping fish (ASCE, 1982; Fritz, 1980). Specific research and citation
findings are listed "--low:
• Modified traveling screens were installed and evaluated for mechanical reliability and
post-impingement survival at Consolidated Edison Company of New York's Indian Point
Nuclear Generating Station Unit 2. The survival rate for me top three fish species (96
percent of the total) was 62.9 percent for white perch, 60.2 percent for striped bass, and
92 percent for rainbow smelt (EPRI, 1989).
• New York State ?**«* Electric Company is evaluating, at its Somerset Generating Station,
the fish survival from Ristroph screens fitted with 1 mm mesh. Two underwater cameras
have been installed to evaluate the fish return system. The results of field testing are not
yet available (EPRI, 1989).
• One of the few studies that did provide evidence for long-term survival was condiJted at
die Hanford Generating Plant on me Columbia River (Page et al., 1975; Fritz, 1930). In
mis study, 79 to 95 percent of the impinged and collected sbinook salmon fry survived for
over 96 hours.
DESIGN CONSIDERATIONS:
• The screens are designed to withstand a differential pressure across their ace of 4 to 8
feet of water.
• The recommended maximum water velocity through the screen is about 2.5 feet per
second (ft/sec). At or below mis velocity, fish ftntrainment and impingement are
negligible (ASCE, 1982).
• The screens normally travel at one speed (10 to 12 feet per minute) - *vo speeds (2.5 to
3 feet per minute and 10 to 12 feet per minute). These speeds can rt. .^creased to handle
heavy debris loads.
A-5
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ADVANTAGES:
• Traveling screens are a proven off-the-shelf technology that is readily available. Aa
CSSCDtlfll Z63tQF6 01 SUC& SCF6COS IS QQFty|nyiiMy OP6f3tlOO OUflD£ DGflOQS Wu6F6 X1SD
being impinged compared to conventional traveling screens, which operate on an
intermittent basis.
LIMITATIONS:
• *>"tfrmniME operation has resulted in undesirable maimrnanre problems (Mussalli, 1977).
• Velocity distribution across the face of the screen is generally very poor.
REFERENCES:
ASCE. Design of Water In**fce Structures for Fish Protection. American Society of Civil
i. New York, NY. 1982.
EPRI. Inmire Technologies: RL, ^.areh Status. Electric Power Research Institute GS-6293.
March 1989.
Fritz, E.S. Cooling Water In^^e Screening Devi**** Used to Reduce Entrainment and
Impingement. Topical Briefs: Fish and Wildlife Resources and Electric Power Generation, No.
9. 1980.
King, LJL, J.B. Hutchinson, Jr., T.G. Huggins. "Impingement Survival Studies on White
Perch, Striped Bass, and Atlantic Tomcod at Three Hudson Power Plants." In Fourth National
Workshop on Entrainment and Impingement. LJ>. Jensen (Editor) Ecological Analysts, Inc.,
Melville, NY. Chicago, IL. December 1977.
Mussalli, Y.G. "Engineering Implications of New Fish Screening Concepts." In Fourth National
Workshop on Entrainment and Impingement. L.D. Jensen (Editor). Ecological Analysts, Inc.,
Melville, NY. Chicago, IL. December 1977. pp 367-376.
Pagano, R., ?"** W.H.B. Smith. Recent Developments in Techniques to Protect Aquatic
Organisms at the Intakes Steam-Electric Power Plants. MITRE Technical Report 7671.
November 1977.
Page, T.L., RJI. Gray, and E.G. Wolf. Report on Impingement Studies Conducted at the
Hanford Generating Project—March and April 1976. Report to Washington Public Power Supply
System. Battelle - Northwest, Richland, WA. 1976.
Richards, R.T. "Present Engineering Limitations to the Protection of Fish at Water Intakes." In
Fourth National Workshop on Entrainment and Impingement. L.D. Jensen (Editor). Ecological
Analysts, Inc., Melville, N.Y. Chicago, IL. December 1977. pp. 415-424.
White, J.C., and M.L. Brehmer. "Eighteen-Month Evaluation of the Ristroph Traveling Fish
Screens." In Third National Workshop on Entrainment and Impingement. L.D. Jensen (Editor).
Ecological Analysts, Inc. Melville, NY. 1976.
A-6
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U.S. EPA. Development Document for Best Technology Available for the Location. Design.
Construction- md Capacity of Cooling Water IotEiOc_Sjnmuices_for_^fininiFyiiig Adverse
Envire"infflttl Iptp^ct. U.S. Environmental Protection Agency, Effluent Guidelines Division,
Office of Waer and Hazardous Materials. April 1976.
A-7
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INTAKE
FACT SHEET NO. 3
INCLINED SINGLE-ENTRY,
TRAVELING SCREENS (ANGLED SCREENS)
DESCRIPTION:
The inclined traveling screens utilize standard dirough-flow traveling screens where die
screens are set at an angle to die incoming flow as shown in die figure below. Angling the
SGV6GOS IBBWOVCS ul£ uSO PTOtBCtlOO CD6CQVCOCSS SXQCC tDC DSD tCOu tO 3VOJU u&G SCTOCD &C6
and move toward me end of die screen Ime, assisted by a component of die inflow velocity.
A fish bypass facility widi independently induced flow must be provided. The fish have to be
lifted by fish pump, elevator, or conveyor and discharged to a point of safety away from die
main water intake (Richards, 1977).
I RECOVERY
SYSTEM
•TRASH BARS
Inclined
Traveling
(Richards, 1977)
A-8
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Angled screens have been tested at die following facilities: New England Power
Company's Brayton Point Station Unit 4; Southern California Edison San Onofre Station;
and power plants on Lake Ontario and die Hudson River (ASCE, 1982).
RESEARCH/OPERATION FINDINGS:
• Testing at die New England Power Company's Brayton Point Station Unit 4 indicated mat
die survival efficiency for die major taxa fTh*b}tfd an extremely wide range, from 0.1
percent for bay anchovy to 97 percent for tantog. Generally, die taxa fell into two
groups: a hardy group with efficiency greater than 65 percent and a sensitive group with
efficiency less dian 25 percent.
• Southern California Edison at its San Onofre steam power plant bad more success with
angled louvers dian with angled screens. The angled screen was not further considered
because of die large bypass flow required to yield acceptable guidance efficiencies.
Angled screens were not successful at San Onofre because the ruVi-ely high
approach velocity of 2 feet per second (ft/sec) diat could be attain • at die station.
DESIGN CONSIDERATIONS:
Many variables mfiuence die |f * "->i "**"«y of angled screens. The following recommended
preliminary design criteria were developed in die studies for the Lake Ontario and Hudson
River intakes (ASCE, 1982):
• Angle of screen to die waterway: 25 degrees.
• Average velocity of approach in die waterway upstream of the screens: 1 foot per
second.
• Ratio of screen velocity to bypass velocity: 1:1.
• Minimum width of bypass opening: 6 niches.
ADVANTAGES:
• The fish are guided instead of impinged.
• The fish remain in water and are not subject to high pressure cleaning.
LIMITATIONS:
• Costs are higher dian for conventional traveling screen.
• Angled screens need a stable water elevation.
• Angled screens require fish hanjifag devices with independently induced flow (Richards,
1977).
A-9
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REFERENCES:
ASCE. Pegjyn of Water Intairg Structures for Fish Protection. American Society of Civil
Engineers. New York, NY. 1982.
Richards, R.T. Present Engmeering IJniitarioiis to me Protection of Fish at Water Intakes.' In
Fourth National Worfafrgp grj pmraiiqn^m ftu^ Jmj|pgeineiit. L.D. Jensen (Editor). Ecological
Analysts, Inc., Mdvflle, NY. Chicago, DL December 19T7. pp. 415-424.
U.S. EPA. PcvelopinBiit Document for Bgst Tgrf***^*^?v AvailflMff fef the Location
CopstTumiop. _8ndCapaciiy_Pf_CQOlinE_j^atCT_Iffl3lreSffut:tutg' for Minimizing Adverse
Environmental \1Wai? U.S. Environmental Protection Agency, EfQuent Guidelines Division,
Office of Water and Hazardous Materials. April 1976.
A-10
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INTAKE SCREENING SYSTEMS
' ? FACT SHEET NO. 4 1
SINGLE-ENTRY, DOUBLE-EXIT VERTICAL
TRAVELING SCREENS
DESCRIPTION:
Single-entry, double-exit vertical traveling screens, known also as Passavant screens, were
developed in Europe almost 30 years ago. The screen structure is mounted in a concrete well
(well setting) or mounted on a platform surrounded by water (open setting). The screens are
arranged in an fadlcss bete "^ can be rotated continuously for an extended period of time.
Water fntfrr the cffitfr of the tcrtfns *"^ paffff? from die inside to die outside of die
screening surface as shown :" Figure 1. An screened particles are removed by a spray from
the outside and are collects < waste trough inside the screens. The screen surface is
theoretically double that of >aventional vertical traveling screens (Fritz, 1980). Various
shapes of screen panels can ~&4, but the use of die semi-circular screen basket increase s
the screening area by approx*. aaiy 60 percent and facilitates the removal of fish. These
basket panels have a vertical ws-2r retaining lip along the bottom which retains debris and ish
until the basket rotates directly over a sluice trough as shown in Figure 2.
MVMkL
Figure 1
Passavant Screen (Sid
-------
TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• The Passavant screens are presently in operation in only two major U.S. steam electric
power plants: the Central Power & Light Company's Barney Davis Station in Corpus
Christi, Texas, and the Commonwealth Edison Company's Lassalle Nuclear Station in
Seneca, Illinois.
RESEARCH/OPERATION FINDINGS:
• The Central Power & Light Company's study of a Passavant Screen (Murray etal., 1978)
with a fffsh swf- of 0.5 "iltl did not jnd'catf mat the single-entry, double-exit traveling
screens are more effective at reducing impingement than the modified vertical traveling
screens (Fact Sheet No. 2). The study reported high survival rates of 86 percent for
impinged organisms. However, mis survival rate was estimated from observations made
only 10 to IS minutes after collection. No results were reported for latent mortality or
survival rates of larvae.
DESIGN CONSIDERATIONS:
• The semicircular design of the basket theoretically provides about 60 percent more screen
area t*1?*1 a flat basket. However, the actual increase in area for a screen modified for
fish recovery is only 10 to 15 percent because of the proximity of the baskets to one
another and to the provision of a closed bucket for fish holding at the bottom end (ASCE,
1982; Mussalli et al., 1978).
• The amount of spray water ranges from 6 to 7 gallons per minute (gpm) per foot of
screen (ACSE, 1982).
• Maximum velocity through the center port is 3.3 ft/sec (ASCE, 1982).
ADVANTAGES:
• In the Passavant screens, mere is no possibility of debris carryover to the dean water
side.
• Passavant screens have a larger screening area man the through-flow screen.
LIMITATIONS:
• The velocity of flow entering between the screen faces is usually high, which leads to
increased impingement and entramment (Richards, 1988).
• The well setting can contribute to higher impingement because the required screen well
can act as an entrapment device.
• The use of fine mesh screens should reduce emrainmem but can cause simultaneous
increases in impingement of fish eggs an^ larvae.
A-12
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The cost of die screens are 15 to 20 percent higher than for both die dual-flow screens
(Fact Sheet No. 5) and die conventional traveling screens (Fact Sheet No. 1) (Richards,
1988).
ASCE. Design of Water Intake Structures for Fish Protection. American Society of Crvfl
Engineers. New York, NY. 1982.
Fritz. E.S- CftfflillP Water Intake Serffflin£^ffylces_ITsfdtp Reduce Entniiiiiueiu and
Impingement. Topical Briefs: Fish and Wildlife Resources and Electric Power Generation, No.
9. July 1980.
Magtiente, S.H., D.A. Tomljanovitch. J.H. Heuer, S. Vigander, and M. N. Smith.
Investigations on die Protection of Fish Larvae at Water Intakes Usine Fine-Mesh Screening.
Impingement Release Concept: Laboratory of Single-Entrance Double-Exit, Vertical Traveling
Screen Concept." In Larvgj Exclusion Systems for Power Plant Cooling Waffl* lnT?*r?5 ^*fl
Diego, CA. February 1978. pp. 69-77.
Murray, L.S., and T.S. Jinnette. "Survival of Dominant Estuarine Organisms Impinged on Fine-
Mesh Traveling Screens at the Barney M. Davis Power Station." In Lim^1 Delusion Systems
for Power Plant Cooling Water Intakes. San Diego, CA. February 1978. pp. 79-87.
Mussalli, Y.G., Taft, E J». and P. Hermann. "Biological and Engineering Considerations in the
Fine Screening of Small Organisms From Cooling Water Intakes." In Larval Exclusion Systems
for Power Plant Coolinp Water Intakes. San Diego, CA. February 1978. pp. 107-123.
Richards, R.T. "Alternative Water Screening for Thermal Power Plants." ASCE Journal of
Hydraulics Engineering. Vol 114, No. 6. June 1988. pp. 578-597.
Siddle, K.R. and R.K. Sharma. •Engineering Aspects of Passavant Screens." In;
Systems for Power Plant Cooling Water Intatot, San Diego, CA. February 1978. pp. 65-68.
A-13
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FACT SHEET NO. 5
DOUBLE-ENTRY, SINGLE-EXIT
VERTICAL TRAVELING SCREEN
(DUAL FLOW SCREENS)
DESCRIPTION:
Double-entry, single-exit (dual flow) vertical traveling screens consist of a screen structure
mourned in a concrete well (well setting) or mourned on a platform surrounded by water (open
setting) as shown below. The unit is turned so mat the approach flow is parallel to the faces of
the screen. Water enters from bom the ascending and descending sides of the screens and
discharges from the downstream end between die faces while the upstream end is blocked off.
The screen faces, operating mechanism, screen speed, and spray wash system are similar to the
conventional traveling screen (Fact Sheet No. 1). In the open setting concept, the pump is
attached directly to the screen. The open setting offers increased fish protection since mere is no
confining structure, such as a well, that may trap fish (ASCE, 1982). The dual flow screen is
used in Europe but is not popular in the United States.
Dual Flow Traveling Screens—Open Setting (ASCE, 1982)
A-14
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
Several facilities have installed or are reviewing the installation of dual flow screens primarily
as a way to *ncreasf debris handling capabilities (EPRI, 1989). The following facilities
the dual flow screens for «»ipmy*»g"f*
• Baltimore Gas and Bectric's Calvert Cliffs Nuclear Power Plant
S CjQQOf B&YOtt 5C8DQD
• Nidgani Mohswk Power Corporation's Dunkirk Stem Ststion
RESEARCH/OPERATION FINDINGS:
• Results from these studies do not indicate any significant increase in impingement survival
over conventional vertical tnveiing screens, especially when the dual flow screens are
incorporated at an intake designed with low approach velocities (EPRI, 1989).
• Because dual flow screens have been installed at water intakes for their debris
capabilities and not to satisfy environmental concerns, only i*™**** information is
available on imninsensent and survival unoacts*
DESIGN CONSIDERATIONS:
• The screen faces, operating mechanisms, screen speed, and spray wash system are similar
to the conventional traveling screen (Fact Sheet No. 1).
ADVANTAGES:
• No debris is •carried-over' into the dean water side. Any material not removed by the
spray system returns to the unscreened waterway on die descending screen.
• Increased screening area is available for a given v . :• of screen.
LIMITATIONS:
• Fish impinged on the descending side wfll remain impinged for a longer period than they
would on a conventional traveling screen, assuming equal screen speeds (ASCE, 1982).
• Because the well setting requires abrupt changes in water flow direction as the water
passes through the screen, the velocity distribution across the screen face is uneven. This
may result in more fish becoming impinged (U.S. EPA, 1976).
• The well setting does not provide any escape route for fish other than swimming back out
of the channel.
ASCE. Design of Water Intake Structures for Fish Protection. American Society of Civil
Engineers. New York, NY. 1982.
A-15
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EPRI. Intake Technology: Research Status. Electric Power Research Institute. EPRI GS-6293.
March 1989.
U.S. EPA. Development Dnemnent for P«*t Technology Available for the Location. Design.
rottsmiericm. and rarity rf Cnnihur Water Intake Structures far Minhnghig Advene
Environmental Inmaet. U.S. Environmental Protection Agency, Effluent
Guidelines Division, Office of Water and Hazardous Materials. April 1976.
A-16
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INTAKE SCREENING SYSTEMS
FACT SHEET NO, 6
HORIZONTAL TRAVELING SCREENS
DESCRIPTION:
Horizontal traveling tcrf*1^ are tfOfMirw^nffy moving screens that span the 'nrr>Tr|'"£ flow of
water. Hie screens rotate horizontally in the waterway with the upstream face placed at an
angle to guide fish in a manner similar to louvers and angled screen systems. The screens are
designed to guide juvenile and adult fish to a bypass without impingement and to collect fish
larvae ***d *gg* «nrf cany thwn to the figh bypass for removal. Many mechanical problems
have occurred during screen testing and have delayed further research (ASCE, 1982). These
mechanical problems result mainly from the high speed continuous operation requirements of
the horizontal traveling screens. Pfftmre of these operational limitations, the screens are not
currently manufactured. Application of these screens to large industnal intakes would likely
require extensive and costly research (EPA, 1976).
Trash Racks Downstream
(not shown)
Horizontal Traveling Screen (ASCE, 1982)
A-17
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Horizontal traveling screens have not been successfully operated at steam electric power
plants.
RESEARCH/OPERATION FINDINGS:
• Foil scale testing on die Grande-Ronde River near Troy, Oregon have shown that die
screens (designated Mark YE) are very effective in reducing impingement and
entraimnent. However, due to considerable ^TpffiiKVtiil limitations, die screens were
never fully developed (Prentice, 1973).
DESIGN CONSIDERATIONS:
• None Found.
ADVANTAGES:
• The horizontal travel^ screens form a complete physical barrier.
• The screens show a high diversion efficiency of fish and release impinged fish into a
bypass widtont passing die air-water interface.
LIMITATIONS:
• The screens can only be used where water depm does not exceed approximately 10 feet (3
meters).
• The screens are only effective where the water level is relatively constant, a condition
which rarely exists at steam electric power plants.
REFERENCES:
ASCE. Design of Water Inmira Structures for Fish Protection. American Society of Civil
Engineers. New York, NY. 1982.
Prentice, E.F., and FJ. Ossiander. "Fish Diversion Systems and Biological Investigation of
Horizontal Traveling Screen Model VII." In Second Workshop on Entraimnent and Intake
Screening. Baltimore, MD. February 1973.
U.S. EPA. Development Document for Best Technology Available for the Location. Design.
Construction, and Capacity of Cooling Water TnQfct Structures for Minimizing Adverse
Environmental Impact. U.S. Environmental Protection Agency, Effluent Guidelines Division,
Office of Water and Hazardous Materials. April 1976.
A-18
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INTAKE SCREENING SYSTEMS
JACT SHEET NO. 7
FINE MESH SCREENS MOUNTED ON
TRAVELING SCREENS
DESCRIPTION:
Fine tn?s*> screens are used for screening eggs- larvae, and juvenile forms of fish from
cooling water intake systems. Toe concept of using fine mesh screens for exclusion of larvae
ITliffi ffll gflltlf frTmggfiinitf mi th» MMB mrfaee nr retention of larvae within the sen
hayiM* washing of screen panels or frayfcfg to transfer organisms into a sluiceway, and men
sluicing the organisms back 10 the source waterbody (Sharma, 1978). Fine mesh with
*ffmtna* g$ small 3$ 0.5 mflluneters (mm) has been used depending on me size of the
organisms to be protected. Fine mesh screens have been used on conventional traveling
screens and single-entry, double-exit screens. The ultimate success of an installation using
fine mesh screens is contingent on the application of satisfactory handling and recovery
facilities to allow the safe return of impinged organisms to the aquatic environment (Pagano et
ah, 1977).
Criteria for the design, operation, and maintcr^uice of traveling screens are very well
established for the standard 3/8 inch mesh screen. Metal screens can be used with both types
of vertical traveling screens, whereas screens of synthetic fabric have been used in the single
entry, double-exit design only. The use of synthetic fabric has not been demonstrated for the
ventional vertical
TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• In early 1979, Tampa Electric Company (TEC) evaluated a prototype dual flow screen
system with 0.5 mm fine mesh at its Big Ben Station as pan of a 316(b) demonstration
project.
• Central Hudson af*d Gas Electric Corporation inyailed woven wire 3.2-mm fine mesh
screens on three vertical traveling screens at Danskammer Point Generating Station Unit 3
located on the Hudson River.
RESEARCH/OPERATION FINDINGS:
• Tampa Electric Company conducted additional biological studies during the 1987
spawning season to verify expected screening efficiencies. Screening efficiencies of 95
percent for eggs, 85.5 percent for larvae, and 100 percent for in
(Brueggemeyer et al., 1988).
rtebrates were reported
Preliminary results from a study initiated in 1987 by the Central Hudson and Gas Electric
Corporation indicate that the fine mesh screens collect smaller fish compared to
conventional screens; mortality for the smaller fish was relatively high, with similar
survival between screens for fish in the same length category (EPRI, 1989).
A-19
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• Generally, the use of fine mesh on conventional traveling screens has not been
demonstrated as an effective technology for reducing mortality or emrainment losses
(EPRI 1989).
DESIGN CONSIDERATIONS:
Biological effectiveness for the whole cycle, from impingement to survival in the source water
body, should be investigated thoroughly prior to implementation of this option. This includes
the following:
• The intake velocity should be very low so mat if mere is any impingement of larvae on
the screens, it is gentle enough not to result in damage or mortality.
• The wash spray for the screen panels or me baskets should be low-pressure so as not to
result in mortality.
• The sluiceway should provide smooth flow so mar mere are no areas of high turbulence;
enough flow should be maintained so that the skH(£way is not dry at any time.
• The species life stage, size, and body shape and the ability of the organisms to withstand
impingement should be considered with time and flow velocities.
• The type of screen mesh material used should be considered. For instance, synthetic
meshes may be smooth and have a low coefficient of friction, features that might help to
minimi™, abrasion of small organisms. However, they also may be more susceptible to
puncture man metallic meshes (Mussalli, 1977).
ADVANTAGES:
* There are indications that fine mesh screens reduce
-------
Pagano, R., and W.H.B. $**"* Recent Developments in Techniques to Protect Aquatic
Organisms at die Water Intakes of Steam-ElfflrJg Iftvpr Plants. Prepared for Beetricite1 de
Fiance. MITRE Technical Report 7671. November 1977.
Mussalli, Y.G., E.P. Taft, and P. Hofnann. "Engineering Implications of New Fish Screening
Concepts." In Fourth Workshop oq JkyY^l Ejcchision Systems for Power Plant Cooling Water
San Diego, CA. February 1978. pp. 367-376.
RJL, "A Synthesis of Views Presented at die Workshop." In LtiT^Til Exclusion Systems
for Power Plant finolmy Water IntaKSf SIP Diego, CA. February 1978. pp. 235-237.
A-21
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INTAKE SCREENING SYSTEMS
•FACT SHEET NO. *
HORIZONTAL DRUM SCREENS
DESCRIPTION:
Horizontal drum screens, widely used outside the United Sates, ire screens mounted on large
revolving wheels. The screens are placed with their longitudinal axis horizontal across the
intake channel. In general, the size of the structure required to mount such screens is
mhtumi^iy larger than use size of the structure required for a traveling screen of similar
capacity. There is little evidence to indicate that these screens offer any fish protection
advantage over the conventional traveling screens (ASCE, 1982). Several variations of
horizontal drum screens are briefly described below.
Water enters the open and unscreened end of the rotating cylinder and exits through the
screened periphery. The drum is limited in size to about 30 feet (9 meters) ki diameter
because of the cantilever nature of the shaft support. The drum is only used v.; low capacity
intakes (EPA, 1976; ASCE, 1982; Richards, 1988).
ocwus MCMOVAL STCICM
U-4- I *~u
* *u«««—wu* «^ •• M«a«
'o«(cno«ef now
I WAT1H
r™at
Single-Entry Rotating Drum Screen (EPA, 1976)
A-22
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Double-Entry Rotating Drum Screen:
Water eaten both ends of a rotating cylinder and exits through the screened periphery.
Diameters up to 80 feet (24 meters) have been installed, and 30 to 40 feet (9 to 12 meters)
dJMMfrnr drums are csmmtm This type of drum screen is less widely used than the single-
dnrv dr Qfi
Double-Entry Rotating Drum Screen (ASCE, 1976)
Drum
Water flows from outside to the inside of the drum. The manufacturer claims that mis type of
drum screen avoids the problem of debris collecting inside the cylinder. Debris collection is a
problem for both the single-entry and double-entry drum screens.
TRASH TIWOW
Outside-*o-Inside-Flow Drum Screen (Richards, 15)88)
A-23
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Dnna screens are not used at U.S. steam power plants.
RESEARCH/OPERATION FINDINGS:
•
There is little evidence to indicate mat horizontal drum screens offer any fish protection
advantage over die conventional traveling screens (ASCE, 1982).
DESIGN CONSIDERATIONS:
• important design parameters inchvff mesh size, drum $\wn*t,Tr. dram rotation velocity,
and flow velocities mrough the screens. The water flow velocities through the screens are
difficult to control since portions of die screen are alternately moving with and against die
intake flow (EPA, 1976).
ADVANTAGES:
• The main advantages of horizontal drum screens are their simp] icty, fewer moving parts
dian conventional traveling screens, and ease of maintenance. For instance, die failure of
die screen wash system would not necessarily stop screen operation as it would for
traveling screens (Richards, 1988).
LIMITATIONS:
• The mam disadvantage of the horizontal drum screen is capital cost. The screen structure
is more costly than the conventional traveling screens hwausf of the larger size.
Estimates show that horizontal drum screens cost approximately $821,000 more dun
conventional traveling screens (1982 dollars). Increased costs result from power,
operation, and "*q"**?*qncf costs (Richards, 1988).
ASCE. Design of Water Intake Structures for Fish Protection. American Society of Civil
Engineers. New York, NY. 1982.
Richards, R.T. "Alternative Water Screening for Thermal Power Plants." ASCE Journal of
Hydraulics Engineering- Vol 114, No. 6. June 1988. pp. 578-597.
U.S. EPA. Development Document for Best Technology Available for die Location. Design.
Construction, and Capacity of Cooling Water Intake Structures for Minimizing Adverse
Environmental Impact. U.S. Environmental Protection Agency, Effluent Guidelines Division,
Office of Water and Hazardous Materials. April 1976.
A-24
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INTAKE SCREENING SYSTEMS
L JACT SHEET NO. 9
VERTICAL DRUM SCREENS
DESCRIPTION:
Vertical drum screens consist of a screen placed on a vertical revolving drum located across
8D iiltjUfff ODCOID2 ID fiPOCt Oi tOC pUXUDS* *» SGDCOlettlC Ol tuC VCTT1C21 uTUTH SCF6CQ IS OCPICTCu
below. Water passes through the screens, and debris is washed from the screens by vertical
jet sprays placed inside the drums. This arrangement operates well under conditions of
fluctuating water levels. In theory, submerged water jets would clean the screen during
rotation; however, without a strong fluyhfay current to cany removed organisms and debris,
this material would simply reimpinge and jam in the seal ing area between the screen and the
support pier. This type of screen has limned use at water intakes and has not been developed
for steam power plant application. The maximum flow rate that can be accommodated by a
vertical drum screen is about 5,000 gallons per minute (EPA, 1976; ASCE, 1982).
Vertical Drum Screen (EPA, 1976)
A-25
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TESTING FAdLTTIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Vertical dnnn screens are not used at U.S. steam power plants. However, they are used
for fish diversion in irrigation canals and in British steam electric stations for protection of
salmoaids with variable success (Eicner, 1974).
RESEARCH/OPERATION FINDINGS:
• Since larger types of vertical drum screens have not been developed, their reliability is
unknown (ASCE, 1982).
DESIGN CONSIDERATIONS:
• None found.
ADVANTAGES:
• Water level variations can be handled without difficulty.
LIMITATIONS:
• Vertical drum screens are limited to low flow situations. The technology requires a
strong flushing current (such as a passing river flow) to carry removed organisms and
debris away from the intake.
REFERENCES:
ASCE. Design of Water Intake Strnetnres fer Fish Protection American Society of Civil
New York, NY. 1982.
Eicher, GJ. "Adaptation of Hydro Fish Facilities to Steam-Electric Stations.' In Second
Workshop on Entrammemt gflj InBftt SffTEP1""?- Electric Power Research Institute, RP-49.
1974. pp. 199-203.
U.S. EPA. Development Document for Best Technology Available for the 1,-ociifion. Design.
Environmental Impact. U.S. Environmental Protection Agency, Effluent Guidelines Division,
Office of Water and Hazardous Materials. April 1976.
A-26
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INTAKE SCREENING SYSTEMS
FACT SHEET NO. 10
ROTATING DISK SCREEN
DESCRIPTION:
A in<«*ii^ disk screen cunsisu of a fouling disk covered by mesh that is *f>gta**fff at
angles to the water channel. A rotating disk screen is depicted in the figure below. The disk
rotates around a horizontal axis, bringing the doty screen ace above water where higb-
pressure sprays wash the debris into a trough. Much of the debris may fall off and remain in
the waterway, thus reducing the efficiency of the screen for debris removal. No more than 35
percent of the total screen ace is used at any one time. This screen is only suitable for
relatively small flows and small water level variations. The rotating disk screen has no
advantage over other common screens for fish protection (EPA, 1976; ASCE, 1982).
Rotating Disk Screen 5CE, 1982)
A-27
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Rotating disk screens are not used at U.S. steam power plants.
RESEARCH/OPERATION FINDINGS:
• None found.
DESIGN CONSIDERATIONS:
• None found.
ADVANTAGES:
• The rntar'tl£ disk* screen has few moving partsim^ is inexpensive to buy an^ maintain
LD STATIONS:
Rotating disk screens have a high probability of fish impingement; require high pressure
sprays to remove fish and debris; and require a very large screen structure to reduce
screen approach velocities.
• The screen is limited to relatively low water flows.
REFERENCES:
ASCE. Task Committee on Fish-handling of Intake Structures of the Committee of Hydraulic
Structures. Design of Water Intake Structures for Fish Protection. American Society of Civil
Engineers. New York, NY. 1982.
U.S. EPA. Development Document for Best Technology Available for the Location. Design.
Construction, and Capacity of Cooling Water liyire Structures for Minimizing Adverse
Environmental Impact. U.S. Environmental Protection Agency, Effluent Guidelines Division,
Office of Water and Hazardous Materials. April 1976.
A-28
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rACTSHEETNO.il
INTAKE SC
DESCRIPTION:
A fixed screen system typically consists of two sets of screens vertically installed prior to die
intake pumps. These screens, generally mounwl in a frame, are installed in vertical tracks on
me intake channel walls and lifted out of me water for cleaning. At least one set of back-up
screens is in position at all times (Ray et al., 1976). Fixed screens are primarily used at
jmaif** where suspended debris is negligible, resulting in minimal cleaning requirements
(EPA, 1976).
TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Forty-six steam electric units are using fixed screens as then: primary water screening
device (EH, 1993). The intake flow associated with these units is relatively low ranging
from 1 to y MGD. The combined total intake flow of all these units (once-through and
dosed cycle? » 440 MGD.
RESEARCH/OPERATION FINDINGS:
• None found.
DESIGN CONSIDERATIONS:
• None found.
ADVANTAGES:
• None found.
LIMITATIONS:
• Operators must be available at all times to maintain the screens.
• Long impingement times between cleaning periods result hi total mortality of fish.
• There is a possibility mat a heavy load of debris or fish could completely clog the intake
and cause plant shutdown and/or screen collapse (Ray et al., 1976).
it K:» H i>i<*M^T?jg?
EH Power Statistics Database. Prepared by the Utility Data Institute for the Edison Electric
* •- nr «_ • .. w^ ^* • ******
Institute. Washington, D.C. 1993
Ray, S.S., RX. Snipes, and D.A. Tomljanovitch, A State-of-the-Art Report on Intake
Technologies. Prepared for the Office of Energy, Minerals, and Industry, Office of Research and
Development, U.S. Environmental Protection Agency, Washington D.C. by the Tennessee Valley
Authority. EPA 600/7-76-020. October 1976.
A-29
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U.S. EPA. Development Doemnent for Best Technology Available for the Location. Design.
Constroction._8Bd_CflPaeitv of Cooling Water Int^Ve Structures for Minimizing Adverse
Environmental Impact. U.S. Environmental Protection Agency, Effluent Guidelines Division,
Office of Water and Hazardous Materials. April 1976.
A-30
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PASSIVE INTAKE SYSTEMS
FACT SHEET NO. 12
WEDGE-WIRE SCREENS
ITON:
Wedge-wire screens, also called profile screens or Johnson screens, are dfdg"*'1 to reduce
entraiiimeut by physical exclusion and by exploiting hydrodynamics. The screen is composed
of wedge-wire loops welded at the apex of their triangular cross section to supporting axial
rods. Hie base of the cross section is presented to die "M*""*"g flow (Pagano et al., 1977).
Physical exclusion occurs when the mesh size of the screen is smaller nan the organisms
susceptible to entraimnenL Hydrodynamic exclusion results from mamtgnaneg of a low
throu~>-slot velocity which, her • of the screen's cylindrical configuration, is quickly
diss- .lid, thereby allowing on
serf • ire usually fV.; mesh (•
figv >Jow. Wedg -wire sere
one. ough system:
; to escape the flow field (Weisberd et al., 1984). The
mm). A cylindrical wedge-wire screen is shown in the
are more suitable for closed-loop make-up intaxes man for
Flow
Schematic of Cylindrical Wedge-Wire Screen (Pagano et al., 1977)
A-31
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TESTING FACXUTIES AND/OR FACILITIES USING THE TECHNOLOGY:
Five U.S. steam electric units use wedge-wire screens as their primary screening devices. All
of these units have a closed-cycle cooling system with intake flows ranging from 8 to 32
MGD (EEL, 1993).
/OPERATION FINDINGS:
• in situ observations have shown that impingement is virtually eliminated when wedge-wire
screens are used (Hanson, 2977; Weisberg et al., 1984).
• Laboratory studies (Heuer and Tomljanovitch, 1978) and prototype field studies (Lifton,
1979; Delmarva Power and Light, 1982; Weisberg et al., 1983) have shown mat fine
wedge-wire screens also reduce entrainment.
• One study (Hanson, 1977) found that entrainment of fish eggs (striped bass), ranging in
from 1.8 mm to 3.2 mm, could be ruminated with a cylindrical wedge-wire
screen incorporating 0 J mm slot openings. Jfr wever, 75 percent of striped bass larvae,
measuring 5.2 mm to 9.2 mm, were generally osirained through a 1 mm slot within 1
minute of release in the test flume.
DESIGN CONSIDERATIONS:
• To tnmimtM dogging, the screen should be located in an ambient current of at least
1 foot per second (ft/sec).
• A uniform velocity distribution along the screen face is required to minimi^ the
entrapment of motile organisms and to fn*n'fft"y the need for debris backflushing.
• In northern latitudes, provisions for the prevention of frazil ice formation on the screens
IDUSt DC GOOS1QCP6Q*
• Allowance should be provided below the screens for silt accumulation to avoid blockage
of the water flow (Mussalli et al., 1980).
ADVANTAGES:
• Wedge-wire screens have been demonstrated to reduce impingement and entrainm^ hi
laboratory and prototype field studies.
LIMITATIONS:
• The physical sire of the screening device is limiting hi most passive systems; thus, many
dusters of screening units are necessary to handle higher flow rates.
• SOtation, biofouling, and frazil ice limit areas where passive screens such as wedge-wire
can be utilized.
A-32
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• Because of these limitations, wedge-wire screens are more suitable for closed-cycle make-
up intakes than once-through systems. Closed-cycle systems require less flow and fewer
screens than once-through intakes; back-up screens can therefore be used during
""A**"*™** work on the wedge-woe screens (MussaUi et al., 1980).
REFERENCES:
Delmarva Ecological Laboratory. Reolopi«»i Studies of the Nantieoke River and Nearby
Vol n. Profile Wire Studies. Report to Delniarva Power and Light Company. 1980.
FPT Pnuier Statistics Database. Prepared by the Utility Data »««>*«""» for die Edison Electric
Institute. Washington, DC. 1993.
Hanson, B.N., W.H. Bason, B.E. Bete, and K£. Charles. "A Practical Intake Screen Which
the Entrahiment and Impingement of Early Life Stages of Fish." In Fc-Jith
National Workshop cm Emafamait and Impingement. LJ). Jensen (Editor). Ecological
Analysts, Inc., Melville, NY. Chicago, IL. December 1977. pp. 393-407.
Heuer, J.H., and D.A. Tomljanovitch. 'A Study on me Protection of r'L- '-/ Larvae at Water
imafciBk Using Wedge-Wire Screening." In Larval Exclusion Systems for Power Plant Cooling
Water Intakes. ILK. Sharmer and J.B. Palmer (Editors). Argonne National Lab. Argonne, IL.
February 1978. pp. 169-194.
Lffion,W.S. "Biological Aspects of Screen Testing on the St. Johns River, Palatka, Florida." In
Screen Intqfrff wftritShOPi Johnson Division UOP Inc. St. Paul, MN, 1979.
MussaUi, Y.G., EJ>. Taft m, and J. Larsen. 'Offshore Water Intakes Designated to Protect
Fish." IfHnj8l^Ltb.CJlMuT8HlisJMyJSilffl-JICP£SffJillK-fl£A Society of Civil
Engineers. Vol. 106. NoHYll. November 1980. pp. 1885-1901.
Pagano R., and W.H.B. Smith. Recer* Developments in Techniques to Protect Aou :ic
Organisms at me Water Intakes of Ste^. • -algctric Power Plants. MITRE Technical I-.eoort 7671.
November 1977.
Weisberg, S J., F. Jacobs, W.H. Burton, yd R.N. Ross. Report on Preliminary Studies Using
the Wfflge Wire Ser»*»Q Model Iiy^"* Facility. Prepared for State of Maryland, Power Plant
Siting Program. Prepared by Martin Marietta Environmental Center. Baltimore, MD. 1983.
Weisberg, S.B., W.H. Burton, E.A. Ross, and F. Jacobs. The Effects of Screen Slot Size.
Diameter, and *nirough-Slot Velocity on Entrainment of Estuarine lehthvoplantton
Through Wedge-Wire Screens. Martin Marriena Environmental Studies. Columbia, MD.
August 1984.
A-33
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PASSIVE INTAKE SYSTEMS
TACT SHEET NO. 13
PERFORATED Fires
DESCRIPTION:
Perforated pipes draw water through perforations or slots in a cylindrical section placed in die
waterway. Hie tern 'perforated' is applied to round perforations and elongated slots as
shown in die figure below. Tlie early technology was not efficient, velocity distribution was
poor, and fish protection was not considered (ASCE, 1982). Inner sleeves have been added to
perforated pipes to equalize die velocities entering the outer jff^ipriff"?11^ v/sstf entering a
single perforated pipe intake wuhout an inner sleeve will have a wide range of entranc
velocities widt die highest velocity cuaceuuaied at die supply pipe end. These systems have
been used at locations requiring smaU amounts of water such as make-up water. However,
experience at steam electric plants is very limited (Sharma, 1978).
Perforations and Slots in Perforated Pipe (ASCE, 1982)
TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Nine steam electric ^"i*8 in die United States use perforated pipes. Each of diese units
has closed-cycle cooling systems wnh relatively low make-up intake flow ranging from 7
to 36 MOD (EEL 1993).
RESEARCH/OPERATION FINDINGS:
• Maintenance of perforated pipe systems requires wiUA>l of biofoulmg and removal of
debns from clogged screens.
• For widutrawal of relatively small quantities of water, up to 50,000 gpm, the perforated
pipe inlet widi an internal perforated sleeve offers substantial protection for fish. This
particular design serves die Washington Public Power Supply System on the Columbia
River (Richards, 1977).
• No
pipes.
is available on me fa** of die organisms impinged at me face of perforated
A-34
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DESIGN CONSIDERATIONS:
• The design of these systems is fairly well established for various water intakes (ASCE,
1982).
ADVANTAGES:
primary advantage is the aMrncf of a confiiwd gh«m»i in which fish night become
LIMITATIONS:
• Clogging, frazil ice formation, bkrfbulmg, and removal of debris limit this technology to
snail flow withdrawals.
REFERENCES:
ASCE. Tasfr Conmriff*^ ffn Pifh-haHJljqg nf Intalre Stmaurm$ mf fh<» OmmhUie of Hydraulic
Structures. P«ripn of Water IntaVe Structures for 1rish Protection- American Society of Civil
Engineers. New York, NY. 1982.
EE1 Power Statistics P^frajff Prepared by the Utility Data Institute for the Edison Electric
Washington, DC. 1993.
Richards, R.T. 1977. •Present Engineering Lhnhations to the Protection of Fish at Water
Intakes." In Fourth National Workshop on Entrainment and Impingement. L.D. Jensen (Editor).
Chicago, IL. December 1977. pp. 415-424.
Shanna, R.K. "A Synthesis of Views Presented at the Workshop." In IrBP"*1 Fxclusion Systems
for Power Plant Coolinp Water Intakes. i5an Diego, CA. February 1978. pp. 235-237.
A-35
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PASSIVE INTAKE SYSTEMS
FACT KHKHT NO. 14
RADIAL WELLS
DESCRIPTION;
Hie radial wdl is a horizontal version of a vertical water well drawing water from a
surrounding aquifer. Such wells are developed in the same manner as conventional wells. The
intake consists of a vertical pump caisson, which is sunk below the water table. Several
perforated collator screen pipes (radial collectors) are men jacked out through wall ports into
the surrounding porous aquifer as depicted in the figure below (Richards, 1978). The radial
well fr»yfa». long represented by the Ranney Collector, has a long history of successful
performance. This system offers ™«»«*«n™ protection to aquatic organisms of all sizes, but is
only suitable where there is a porous aquifer. In addition, the associated costs of pumps and a
large piping network limit the radial well for once-through application (Mussalli et al., 1980).
mat
MotUenui
to 300' long.
Radial Well Intake (Richards, 1978)
(Ranney Collector)
A-36
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Radial wells have been in use for over 40 years and have served successfully when
properly located and 4fg«r»«d In 1978, it was estimated that there were more than 300
m operation m the XJmtffu states and ^surooe. «%oout 55 oercent ox
these were used for municipal water supplies, while the rffliahmig 45 percent were
employed for industrial processes and cooling water supplies (MDcels, 1978).
RESEARCH/OPERATION FINDINGS:
• Radial wells offer •«***"""" protection to aquatic organisms of all sizes (ASCE, 1982).
DESIGN CONSIDERATIONS:
• The aquifer must be of a suitably porous material.
• The maximum capacity of a single well is limited to about 25,000 gallons per minute.
• Geological and hydrological considerations are critical in me siting and installation of
these wells because the substrate must have adequate permeability to allow for the flow
from the source water body to the subsurface collector.
• Collector caisson spacing for multiple radial well units is typically 1,500 feet. The typical
of radial collector screens is 8 to 16 inches (ASCE, 1982).
ADVANTAGES:
* The concept is reliable in design and operation and is relatively maintenance free.
• The we: . are suitable for use at freshwater, estuarine. and coastal locations. If economic
factors p. rait, the wells should be preferable to all other control systems for larval
screening (Sharma, 1978).
• Larval exclusion is maximized in radial wells; no impingement or entrainment impacts are
associated ^vtth this system since ^water is ^vithdra^vn xrom underBrouno.
LIMITATIONS:
• Radial wells are only suitable where there is a porous aquifer with the capacity to provide
the quantity of water required for such systems.
• The individual caisson units are limited to about 25,000 gallons per minute in a favorable
aquifer, which limits application of such wells for large volume once-through cooling
A-37
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ASCE. Task Committee on Fish-hamDiag of Intake Structures of the Committee of Hydraulic
Structures. Dcsi£iLjlf^iittCLJlll3lS£-StnifflirK_6tr_Bsfa_£rSIfic^on- American Society of Civfl
Engineers. New York, NY. 1982.
MOcels, F.C., i*"1 T.W. T»*""*** "Cooling Water Tr**1"*? Utilizing Ranney Collectors or Raaney
TM+fiiV^M * ¥*i T •Mivl V*v4*fvtctfiYft CufftiHMC T*f%v Vtaam* Ol^fit ^nAlvfttf Wfltvp Twfst^c Csn ^^i^0n ^ A
February 1978. pp. 15-25.
Mnssalli, Y.G., EP. Taft m, and J. Lanen. "Of&bote Water Intakes Designated to Protect
Fish." |fmmal nf the Hvdrmlies Division. P**v^»«f «y of the A"**"6*** S«eia»y «f P»v«l
Engineers, Vol. 106, No Hyll. November 1980. pp. 1885-1901.
Richards, R.T. •Engmeering Considerations m the Use of Artificial Filter Beds." I
Exclusion Systems for Power Kant Cooling Water Intair«»c gy» Diego, CA. February 1978. pp.
5-12.
Shar*i*fl, R.K. "A Synthesis of Views Presented at the Workshop." In L8TY81 E^SJU5J9I1 Systems
for Powgr ^f»iff Coolinp Wa»*f IlBaJtBS- San Diego, CA. February 1978. pp. 235-237.
A-38
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PASSIVE INTAKE SYSTEMS
FACT SHEET NO. 15
POROUS DIKES
DESCRIPTION:
Porous dikes, also known as leaky dams or leaky dikes, are filters rrtcmhling a breakwater
surrounding a cooling water intake. The cote of the dike consists of cobble or gravel, which
permits free passage of water. The dike acts both as a physical and a behavioral barrier to
aquatic organisms and is depicted in the figure below. The filtering mechanism includes a
breakwater or some other type of barrier and the filtering core (Fritz, 1980). Tests conducted
to ditf have «««*ig»***< fry the technology is effective in excluding juvenile and adult fish.
However, its effectiveness in screening fish eggs and larvae is not established (ASCE, 1982).
• .% rs • * •• • ^^ • ^^^^
:••:.•:/..-A-y-•«.'.•:>:.• >--r?
SECTION A-A
POftOUS
ncroi
PLAN
Porous Dike (Schrader and Ketschke, 1978)
A-39
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
facilities both testing and using the technology are Wisconsin Electric Power
Company's Point Beach Nuclear Plant in Two Rivers and Northern Indiana Public Service
Company's Bafly Generating Station m Charleston (EPRL 1985). New England Power
Company's Brayton Point Generating Station in Somerset, MasMrhiwm, has also tested
the technology .
RESEARCH/OPERATION FINDINGS:
• Sounder and Ketschke (1978) studied the porous dike at Wisconsin Hectric Service
Company's T^V»«H* Plant on Lake Michigan and found that numerous fish penetrated
lane void spaces but for mftiff ^**fr accessibility was
• The biological effectiveness of screening offish larvae and the engineering practuabflny
have not been established (ASCE. 1982).
• The size of the pores m the dike dictates the degree of maintenance due to bkrfbuling and
dogging by debns.
• Ice build-up and frazil ice may create problems as evidenced at the Point Beach Nuclear
Plant (EPRL 1985).
DESIGN CONSIDERATIONS
• The presence of currents past the dike aids hi diverting fish and may increase biological
• The sitf of pores m the fficf dgtfrfii"M>- the ffttfflt of biofbuling F"** clogging by debris
(Sbarma, 1978).
• Filtering material must be of a size that permits free passage of water but still prevents
enrramment anu impingement*
ADVANTAGES:
• Dikes can be used at marine, fresh, and estuarine locations.
LIMITATIONS:
• The major problem with porous dikes results from clogging by debris and silt, and from
fouling by colonization of fish and plant life.
• BarMhishhig, which is often used by other systems for debris removal, is not feasible at a
s
• Predation of organisms screened at these dikes may offset any biological effectiveness
(Sharma, 1978).
A-40
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ASCE. Task Coimnigff OB FfoM"""*1"^ ««* T««al"» Stroemres of rin» Committee nf Hydraulic
Structures. Design of W»»«ff Intshff Structures for Fish Protection. American Society of Civil
New York, NY. 1982.
Intake Research Facilities Manual. Prepaied by Lawlcr, Matusky & Skelly Engineers,
Pearl River, for Electric Power Research Institute. EPRI CS-3976. May 1985.
Fritz, E.S. Cooling Water Intake SerMtihw Heirices Used to Reduce Entrainment and
imnmgemeHt. Fish and Wildlife Service, Topical Briefs: Fish and Wildlife Resources and
Electric Power Generation, No 9. July 1980.
Schnder, B J., and BJL Kft!^1" "Biological Aspects of Porous-Dike Intake Structures.' In
Larval Exclusion Systems fof Power Plant Cooling Water Intay.es. ^m Diego, CA. August
1978. pp. 51-63.
^fianna R.K. "A ^y^hesis of Views Presented at die Workshop." In Larval Exclusion Systems
For Power Bam Ca.->'.^f Water Intakes. San Diego, CA. February 1978. pp. 235-237.
A-41
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PASSIVE INTAKE SYSTEMS
FACT SHEET NO. 16
ARTIFICIAL FILTER BEDS
DESCRIPTION:
Artificial filter bed hitikft ptflirf a prepared granular filttr fnirrriil to present fini j'T? of
debris and aquatic life into a water withdrawal facility. Artificial filter beds have been
extensively used for the filtration of """"«p?> water supplies for a considerable period of
time. The figure below shows a y*«™«ffr of an artificial filter bed. An area is excavated
and back-filled with a specially graded filter medium- A perforated pipe located under this
filter collects the filtered water and carries it to the pomp structure. Clogging and bkrfouling
dnf> to operation ***d silting, decreased water Quality dof to maintenance backwash, *****
limited intake capacity make it unattractive for use at steam electric plants (Richards, 1978;
ASCE, 1982).
•PUMP
•WATER BACKWASH PIPE
AIR BACKWASH PIPE
FILTER
MEDIUM
PERFORATED COLLECTOR
Artificial Filter Bed {Richards, 1978)
A-42
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Artificial filter beds are not operational at steam electric plants.
RESEARCH/OPERATION FINDINGS:
• A filter bed was installed for steam electric plant make-up on the West Branch of the
River to draw make-up water for the Montoor Steam Electric Station of the
Pennsylvania Power and Light Company. The artificial filter bed could not be prevented
from clogging and was abandoned and replaced with a perforated pipe (Richards, 1978).
• Similarly m 1972, a filter bed was first selected for the make-up water system for Nuclear
Project No. 2 of the Washington Public Power Supply System (WPSS-2) oc die Columbia
River. Ultimately, the filter concept was set aside in favor of the modified perforated
pipe (Richards, 1978).
• Although mis concept has high screening potential, consensus was reached in die
Workshop on Larval Exclusion System; for Power Plants Cooling Water Intakes mat
operational difficulties discourage an$ turner research and development of this concept
(Shanna, 1978).
DESIGN CONSIDERATIONS:
• None found.
ADVANTAGES:
• Little or no biological impact is expected to occur as a result of operation of artificial
filter beds.
LIMITATIONS:
• Artificial filter beds can only be shed on water bodies that have low concentrations of
suspended particles and where potential for biofbuling is low.
• dogging and biofbuling due to operation, silting, and decreased water quality due to
maintenance backwash make artificial filter beds unattractive for use at steam electric
plants.
• The artificial filter beds have limited intake capacity.
ASCE. Desipi of Water Inmfce Structures for Fish Protection. American Society of Civil
Engineers. New York. NY. 1982.
Richards, R.T. "Engineering Considerations in the Use of Artificial Filter Beds." In Larval
Exclusion Systems for Power Plant Cooling Water Int?kgs San Dieco CA February 1978 DD
5-12.
A-43
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F.K. "A Synthesis of Views Presented at the Workshop." In LflP^fll Exclusion Systems
for Power Plant Coolinp Water Intakes. San Diego, CA. February 1978. pp. 235-237.
A-44
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FISH DIVERSION OR AVOIDANCE
SYSTEMS
FACT SHEET NO. 17
LOUVER BARRIERS
DESCRIPTION:
Louver barriers are devices comprising a series of vertical panels placed at an angle to the
direction of the flow (typically 15 to 20 degrees). Each panel is placed at an angle of 90
degrees to the direction of the flow (Hadderingh, 1979). The louver panels provide an abrupt
change in both the flow direction and velocity (see figure below). This creates a barrier that
fish can *"*""«K«**'y sense and avoid. Once the change in flow/velocity is sensed by fish,
they typically align themselves with the direction of the current and move laterally away from
the turbulence. This behavior further guides fish into a current created by the system which is
parallel to the face of the louvers. The current pulls die fish along the line of the louvers until
they enter a fish bypass or other fish handling device at the end of the louver line. The
louvers may be either fixed or rotated similar to a traveling screen. Flow straighteners are
frequently placed behind the louver systems.
Louver barriers have been very successful and have been installed ; 'merous
intakes, water diversion projects, and steam electric and hvdroeleccv ftcilities. It appears
mat mis technology has, in general, become accepted as a viable option to divert fish.
Top View of a Louver Barrier with Fish Bypass (Hadderingh, 1979)
A-45
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Louver barrier devices have been tested and/or are in use at the following California
facilities: California Department of Water Resource's Tracy Pumping Plant; me
California Department of Fish and Game's Delta Fish Protective Facility in Bryan; and
the San Onofre Nudear Generating Station m San Clemente (EPA, 1976; EPRI, 1985).
In addition, two other plants also have louvers at their ^iril'tiff Ruth Falls Power Plant
m Nova Scotia and the Nine Mile Point Nuclear Power Station on Lake Erie. Louvers
have also been tested at the Ontario Hydro Laboratories m Toronto, Ontario. Canada (Ray
et al., 1976).
RESEARCH/OPERATION FINDINGS:
Research has shown the following generalizations to be true regarding louver barriers: (l)the
fish separation performance of the louver barrier decreases with an increase m the velocity of
the flow through the barrier; (2) efficiency increases with fish size (EPA, 1976; Hadderingh,
1979); (3) individual louver misalignment has a beneficial effect on the efficiency of the
barrier; (4) the use of center walls provides the fish with a guide wall to swim along, thereby
improving efficiency (EPA, 1976); and (5) the most effective slat spacing and array angle to
flow depend upon the size, species, and swimming ability of the fish to be diverted (Ray et
al., 1976).
In addition, the following conclusions were drawn during specific studies:
• Testing of louvered intake structures offshore was performed at a New York facility. The
louvers were spaced 10 inches apart to *mfaui* clogging. The array was angled at 11.5
percent to the flow. Center walls were provided for fish guidance to the bypass. Test
species included alewife and rainbow smen. The mean efficiency predicted was between
22 and 48 percent (Mussalli 1980).
• During testing as the Delta Facility's intake in Byron, California, me design flow was
6,000 cubic feet per second (cfs), the approach velocity was 1.5 to 3.5 feet per second
(ft/sec), and the bypass velocities were 1.2 to 1.6 times the approach velocity.
Efficiencies were found to drop with an increase in velocity through the louvers. For
example, at 13 to 2 ft/sec the efficiency was 61 percent for IS millimeter long fish and
95 percent for 40 millimeter fish. At 3.5 ft/sec, the efficiencies were 35 and 70 percent
(Ray et al., 1976).
• The efficiency of the louver device is highly dependent upon Ae length and swimming
performance of a fish. Efficiencies of lower than 80 percent have been seen at facilities
where fish were 1.6 inches or less in length (Mussalli, 1980).
• At the Tracy Fish Collection Facility, an efficiency of 97 percent was realized with the
louver placed 15 degrees to the direction of the flow with four evenly spaced bypasses.
The slats were 90 degrees to the direction of the flow and spaced 2.5 ««t!T»nm (cm)
apart (Ray et al., 1976).
A-46
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• At the Maxwell Irrigation Canal in Oregon, louver spacing was 5 cm with a 98 percent
efficiency of deflecting immature stedhead and above 90 percent efficiency for the same
species with the louver spacing of 10.8 cm.
• At the Rum Falls Power Plant in Nova Scotia, the results of a 5-year evaluation for
guiding salmon smelts showed that the optimum spacing was to have wide bar spacing at
the widest pan of the louver wnh a gradual reduction in the space approaching the bypass.
The she used a bypass approach velocity of 1.0:1.5 (Ray et al., 1976).
• Coastal species in California were deflected optimally (Schuler and Larson, 1974 and Ray
et al., 1976) with 2.5 cm spacing of the louvers, 20 degree louver array to the direction
of flow, and approach velocities of 0.6 cm per second.
DESIGN CONSIDERATIONS:
The most important parameters of the design of louver barriers include the following:
• The angle of the louver vanes in relation tome enamel velocity
• The spacing between the louvers as it is relates to the size of the fish
• Ratio of bypass velocity to channel velocity
• Shape of guide walls
• Louver array angles
• Approach velocities.
She-specific modeling may be needed to take into account species-specific considerations and to
optimize the design efficiency (EPA, 1976; OTCeefe, 1978).
ADVANTAGES:
• Louver designs have been shown to be very effective in diverting fish (EPA, 1976).
LIMITATIONS:
• The costs of installing intakes with louvers may be substantially higher man other
technologies because of design costs and the precision required during construction.
• Extensive species-specific field testing may be required.
• The shallow angles required for the efficient design of a louver system require a long line
of louvers, which increase the cost compared to other systems (Ray et al., 1976).
• Water level changes must be kept to a niinimuni to maintain the most efficient flow
velocity.
A-47
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• Fish handling devices are needed to take fish away from die louver barrier.
• Louver barriers may or may not require additional screening devices for removing solids
from the intake waters. If such devices are required, they may add a substantial cost to
the system (EPA, 1976).
• Louvers may not be appropriate for offshore intakes (Mussalli, 1980).
Chow, W., LP. Murarka, and R.W. Broksen. "Entrainment and Impingement in Power Plant
Cooling Systems." Literature Review. Journal of Water Pollution Control Federation. S3 (6)
(1981): 965-973.
EPRI. Intake Research Facilities Manual. Prepared by Lawler, Matusky & Skelly Engineers,
Pearl River, for Electric Power Research Institute. EPRI CS-3976. May 198S.
Hadderingh, R.H. "Fish Intake Mortality at Power Stations, the Problem and its Remedy.* N.V.
Kema, Arnheem, Netherlands. Hvdrologieal Bulletin 13(2-3) (1979): 83-93.
Mussalli, Y.G., EJ>. Taft, and P. Hoffman. "Engineering Implications of New Fish Screening
Concepts." fa Fourth National Workshop on Entrainment and Impingement. L.D. Jensen
(Editor). Ecological Analysts, Inc., Melville, NY. Chicago, IL. December 1977.
Mussalli, Y.G., E.P Taft m, and J. Larson. "Offshore Water Intakes Designed to Protect Fish."
Journal of the Hydraulics Division Proceedings of the American Society of Civil Engineers. Vol.
106 Hyl 1(1980): 1885-1901.
O'Keefe, W. "Intake Technology Moves Ahead." Power. January 1978.
Ray, S.S., R.L. Snipes, and D.A. Tomljanovich. A State-of-the-Art Report on Intake
Technologies. Prepared for Office of Energy, Minerals, and Industry, Office of Research and
Development, U.S. Environmental Protection Agency, Washington, DC by the Tennessee Valley
Authority. EPA 600/7-76-020. October 1976.
U.S. EPA. Development Document for Best Technology Available for the Location. Design.
Construction, and Capacity of Cooling Wjflef T"t?lr? SrVTfl'res for Minimizing Adverse
Environmental Impact. U.S. Environmental Protection Agency, Effluent Guidelines Division,
Office of Water and Hazardous Materials. April 1976.
Uziel, Mary S. "Entrainment and Impingement at Cooling Water Intakes." Literature Review.
Journal Water Pollution Control Federation. 52 (6) (1980): 1616-1630.
ADDITIONAL
Adams, S.M. et al. Analysis of the Prairie Island Nuclear Generating Station Intake Related
Sjudjs. Report to Minnesota Pollution Control Agency. Oak Ridge National Lab. Oak Ridge,
TN. 1979.
A-48
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Bates, D.W., and R. Vinsonhaler, "The Use of Louvers for Guiding Fish." Trans. Am. Fish.
SOL 86 (19S6): 39-57.
Bates, D.W., and S.G., Jewett Jr. 'Louver Efficiency in Deflecting Downstream Migrant
Steelhead." Trans. Am. Fish Soc. 90(3) (1961): 336-337.
G.G., and A.T. Sziuha. 'A Biological Evaluation of Devices Used for Reducing
E&trainmefit nd Impingement Losses at Thermal Power Plants." In Intei national Symposium on
Adfioccs jji v^sta^H
Publication No. 1276. Oak Ridge National Lab. Oak Ridge TN. 1978.
Cannon, JJJ., et al. 'Fish Protection at Steam Electric Power Plants: Alternative Screening
Devices/ ORAL/IM-6473. Oak Ridge National Lab. Oak Ridge, TN. 1979.
Downs, DJ., and K.R. Meddock, "Design of Fish Conserving Intake System." Journal of the
Power Division. ASCE. Vol. 100, No. P02. Proc. Paper 1108 (1974): 191-205.
Ducharme, L J.A. "An Application of Louver Deflectors for Guiding Auntie Salmon (Salmo
salar) S molts from Power Turbines." Joan"! Fisheries Rgsgarch Board of Canada. 29 (1974):
1397-1404.
Hallock, RJ., R.A. Iselin, and DJiJ. Fry. 'Efficiency Tests of the Primary Louver Systems,
Tracy Fish Screen, 1966-67." Marine Resources Branch, California Department of Fish and
Game. 1968.
Katapodis, C., et al. A Study of Model and Prototype Culvert Baffling for Fish Passage.
Fisheries and Marine Service, Tech. Report No. 828. Winnipeg, Manitoba. 1978.
Kerr, J.E., "Studies on Fish Preservation at the Contra Costa Steam Plant of the Pacific Gas and
Electric Co." California Fish and Game Bulletin No. 92. 1953.
Marcy, B.C., and MJ>. Dahlberg. Review of Best Technology Available for Cooling Water
Intake. NUS Corporation. Pittsburgh, PA. 1978.
NUSCorp. "Review of Best Technology Available for Cooling Water Intakes." Los Angeles
Dent, of Water &. Power Report. Los Angeles, CA. 1978.
Schuler, V J. "Experimental Studies in Guiding Marine Fishes of Southern California with
Screens and Louvers." lehthvol. A«oe.. Bulletin 8. 1973.
Skinner, J.E. "A Functional Evaluation of Large Louver Screen Installation and Fish Facilities
Research on California Water Diversion Projects." In L.D. Jensen (Editor), Entrainment and
Intake Screening. Proceedings of the Second Emrainment and Intake Screening Workshop. The
John Hopkins University. Baltimore, MD. February 5-9, 1973. pp. 225-249. (Edison Electric
Institute and Electric Power Research Institute. EPRI Publication No. 74-049-00-5. 1974).
Stone and Webster Engineering Corporation. Final Report. Indian Point Flume Study. Prepared
for Consolidated Edison Company of New York. July 1976.
A-49
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Stone sm^ Webster Engineering Corporation, Studies to Alleviate Potential
Problems— Final Report. Nine Mile Pofait Nuclear Station— Unit 2. Prepared for Niagara
Mohawk Power Corporation. Syracuse, NY. May 1972.
Taft, E.P., and Y.G. Mussalli, "Angled Screens and Louvers for Diverting Fish at Power
Plants." Proceedings of the American Society of Civil Engineers. Journal of Hydraulics
Division. Vol 104 (1978): 623-634.
Thompson, J.S., V^ GJ. Paulick. An Evaluation gf LffllY8*5 *nd PyP, 8ff5 Facilities for Guiding
Seaward Miprant Salmonid Past Mavfield Dam in West Washington. Washington Department of
Fisheries. Olympia, WA. 1967.
Watts, FJ. "Design of Culvert Fishways." University of Idaho Water Resources Research
Institute Report. Moscow, ID. 1974.
A-50
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FISH DIVERSION OR AVOIDANCE
SYSTEMS
FACT SMELT NO. 18
VELOCITY CAP
DESCRIPTION:
A velocity cap is a device that is placed over vertical inlets at offshore intakes (see figure
below). This cover converts vertical flow into horizontal flow at the entrance of the intake.
The device works on die premise that fish will avoid rapid changes in horizontal flow. Fish
do not exhibit this same avoidance behavior to the vertical flow that occurs without the use of
such a device. Velocity caps have been implemented at many offshore intakes and have been
successful in decreasing the *tnping*m«tnt of fish.
v-O.5-l.StM
MFUW
Typical Offshore Cooling Water Intake Structure with Velocity Caps
(Hdrey, 1985; ASCE, 1982)
A-51
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• The available literature (EPA, 1976; Hanson, 1979; and Pagano et al., 1977) states that
velocity caps have been installed at offshore intakes in Southern California, the Great
Lakes Region, the Pacific Coast, the Caribbean, and overseas; however, exact locations
are not specified.
• Velocity caps are known to be installed at the El Segundo, Redondo Beach, and
puHtinpnn Beach Steam Electric Stations and die San Onofre Nuclear Generation Station
in Southern California (Mussalli, 1980; Pagano et al., 1977; EPRI, 1985).
• The Southern California Edison Company now installs velocity caps on all new offshore
intakes (Pagano et al., 1977). Model tests have been conducted by a New York State
Utility (ASCE, 1982), and several facilities have installed velocity caps in the New York
State/Great Lakes Area, including the Nine Mile Pout Nuclear Station in Lycoming, the
Oswego Steam Electric Station, and the Somerset Generation Stations (EPRI, 1985).
• Additional facilities with velocity caps include me Edgewater Generation Station in
Sheboygan, Wisconsin, and the Nantioke Thermal Generating Station hi Nantioke,
Ontario, ra"a<*a (EPRI, 1985).
RESEARCH/OPERATION FINDINGS:
• Horizontal velocities within a range of 0.5 to 1.5 feet per second (ft/sec) did not
significantly affect the efficiency of a velocity cap tested at a New York facility; however,
mis design velocity may be specific to the species present at that site (ASCE, 1982).
• Preliminary decreases in fish entrapment averaging 80 to 90 percent were seen at the El
Segundo and Huntington Beach Steam Electric Plants (Mussalli, 1980).
• Performance of the velocity cap may be associated with cap design and the total volumes
of water flowing into the cap rather than to the critical velocity threshold of the cap
(Mussalli, 1980).
DESIGN CONSIDERATIONS:
• Designs with rims around the cap edge prevent water from sweeping around the edge and
causing turbulence and high velocities, thereby providing more uniform horizontal flows
(EPA, 1976; Mussalli, 1980).
• She-specific testing should be conducted to determine appropriate velocities to minimise
entrainment of particular species in the intake (ASCE, 1982).
• Most structures an sized to achieve a low intake velocity between 0.5 and 1.5 ft/sec to
lessen the chances of entrainment (ASCE, 1982).
• Design criteria developed for a model test conducted by Southern California Edison
Company used a velocity through the cap of 0.5 to 1.5 ft/sec; the ratio of the dimension
of the rim to the height of the intake areas was 1.5 to 1 (ASCE, 1982; Schuler, 1975).
A-S2
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ADVANTAGES:
• Diversion efficiencies of velocity caps in West Coast offshore intakes have exceeded 90
percent (ASCE, 1982).
LIMITATIONS:
• Velocity caps are difficult to inspect because of Iheir location under water (EPA, 197$).
• In some studies, the velocity cap only mhiirnfrfd the enrrainmem of fish and did not
eliminate h. Therefore, additional fish recovery devices are needed when such systems
are used (ASCE, 1982; Mussalli, 1980).
• Velocity caps are ineffective in preventing passage of non-motile organisms and early life
stage fish (Mussalli, 1980).
ASCE. Design of Water In**fre Structures far Fish Protection. American Society of Civil
Engineers. New York, NY. 1982.
EPRI. Intake Reggarth Facilities Manual. Prepared by Lawler, Matusky & Skelly Engim
Pearl River, for Electric Power Research Institute. EPRI CS-3976. May 1985.
Hanson, C.H., et al. "Entrapment and Impingement of Fishes by Power Plant Cooling Water
Intakes: An Overview." Marine Fisheries Review. October 1977.
Mussalli, Y.G., E.P Taft DL and J, Larson. "Offshore Water Intakes Designed to Protect Fish."
Journal of the Hydraulics Division Pro^^^ings of the American Society of Civil Engineers Vol
106 Hyll (1980): 1885-1901.
Pagano R., and W.H.B. Smut. Recent Development in Techniques to Protect Aquatic Organisms
at the Water Intakes of Steam Electric Power Plants. Prepared for Electricite de France. MITRE
Technical Report 7671. November 1977.
Ray, S.S., RX. Snipes, and D.A. Tomljanovich. A State-of-the-Art Report on Intake
Technologies. Prepared for Office of Energy, Minerals, and Industry, Office of Research and
Development. U.S. Environmental Protection Agency, Washington, DC, by the Tennessee
Valley Authority. EPA 600/7-76-020. October 1976.
U.S. EPA.
Construction, and Canatritv of Cooling Water Intake Structures for Minimizing Adverse
Environmental Impact. U.S. Environmental Protection Agency, Effluent Guidelines Division,
Office of Water and Hazardous Materials. April 1976.
A-53
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ADDITIONAL
Maxwell, W.A. Fish Diversion for Electrical Generating Station Cooling Systems—A State of the
Art Report. Southern Nuclear Engineering inc. Report SNE-123. NUS Corporation. Dunedin,
FL. 1973.
Richards, R.T. Tower Plant Circulating Water Systems—A Case Study." Short Course on die
Hydraulics of Cooling Water Systems for Thermal Power Plants. Colorado State University.
June 1978.
Stone atv* Webster Engineering Corporation. Studies to Alleviate Fish Entrapment at Power Plant
Cooling Water Intflfrffii p|fl8! ^ffftft Prepared for Niagara Mohawk Power Corporation and
Rochester Gas atv* Electric Corporation. November 1976.
Weight, JLR. "Ocean Cooling Water System for 800 MW Power Station." J. Power Dhr., Proe.
Am. Soe. Civil Engr. 84(6) (1958): 1888-1 to 1888-222.
A-S4
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FISH DIVERSION OR AVOIDANCE
SYSTEMS
FACT VHKKT NO. 19
FISH BARRIER NETS
DESCRIPTION:
Fish barrier nets are large mesh nets, which are placed in front of die entrance to the intake
structure (see figure below). Hie size of die mesh needed is a function of the species that are
present at a particular site. Fish barrier nets have been used at numerous facilities and lend
themselves to ««**irfy where the sref^nal migration of fish and other organisms requires fish
diversion facilities for only specific times of the year.
V-Amngement of Fish Barrier Net (ASCE, 1982)
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• The Commonwealth Edison Company in New York is reported to make extensive use of
barrier nets to mitigate impingement (EPRI, 1989). The Orange and Rockland Utility's
Bowline Point Generating Station, the Wisconsin Public Service Corporation's J.P.
Pullium Power Plant in Green Bay, and the Nantioke Thermal Generating Station in
Ontario also use barrier nets.
• Barrier Nets have been tested at the Detroit Edison Monroe Plant on Lake Erie and the
Chalk Point Station on the Patuxent River in Maryland (ASCE, 1982; EPRI, 1985). Hie
Maryland station now uses barrier nets seasonally to reduce fish and Blue Crab entry into
tbe «"taife fanal (EPRI, 1985). The Pickering Generation Station in Ontario evaluated
rope nets hi 1981 illuminated by strobe lights (EPRI, 1985).
RESEARCH/OPERATION FINDINGS:
• At the Bowline Point Generating Station in New York, good results have been realized
with a net placed in a V arrangement around the intake structure (ASCE, 1982).
• Impingement at a Wisconsin plant has been reduced by as much as 90 percent using a
barrier net (ASCE, 1985).
• Nets tested with high intake velocities (greater than 1.3 feet per second) at the Monroe
Plant have clogged and subsequentially collapsed. This has not occurred at facilities
where me velocities are 0.4 to 0.5 feet per second (ASCE, 1982).
• Barrier nets at the Nantioke Thermal Generating Station hi Ontario reduced intake of fish
by 50 percent (EPRI, 1985).
• The J J* Pullium Generating Station hi Wisconsin uses dual barrier nets (0.64 centimeters
stretch mesh) to permit net rotation for cleaning. Nets are used from April to December
or when water temperatures go above 4 degrees Celsius. Impingement has been reduced
by as much as 90 percent. Operating costs run about $5,000 per year, and nets are
replaced every 2 years at $2,500 per net (EPRI, 1985).
• The Chalk Point Station in Maryland realized operational costs of $5,000 to $10,000 per
year with die nets being replaced every 2 years (EPRI, 1985).
DESIGN CONSIDERATIONS:
• The most important factors to consider in the design of a net barrier are the site-specific
velocities and the potential for clogging with debris (ASCE, 1982).
• The size of the mesh must permit effective operations, without excessive clogging.
Designs at the Bowline Point Station hi New York have 0.15 and 0.2 inch opening in the
mesh nets, while the P. Pullium Plant in Wisconsin has 0.25 inch openings (ASCE,
1982).
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ADVANTAGES:
• Net barriers, if operating properly, should require very little maintenance.
• Net barriers have relatively little cost associated with them
LIMITATIONS:
• Net barriers are not effective for die protection of the early life stages of fish or
zooplankton (ASCE, 1982).
REFERENCES:
ASCE. Design of Water Intake Structures for Fish Protection. American Society of Civil
Engineers. New York, NY. 1982.
EPRI. Intake Research Facilities Manual. Prepared by Lawler, Matusky & Skelly Engineers,
Pearl River, for Electric Power Research Institute. EPRI CS-3976. May 1985.
Lawler, Matusky, and Skelly Engineers. 1977 Hudson River Aquatic Ecology Studies at the
Bowline Point Generating Stations. Prepared for Orange and Rockland Utilities, Inc. Pearl
River, NY. 1978.
A-57
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Air bubble barriers have been evaluated at the Pickering Nuclear Generating Station
(1985-1986) in Ontario, ra"i"*a: die Seton Hydroelectric facility in British Columbia
(1986), the Nanticoke Thermal Generating Station in Ontario, Canada; the Millstone
Nuclear Power Station on Long Island Sound in Connecticut: the Monroe Power plant in
Michigan; the Quad-Cities Commonwealth Edison Company on the Mississippi River
Power Plant; the Prairie TtianH Nuclear Generating Station in Minnesota; the Michigan
City plant in Indiana; the Indian Point Generating Station in New York; the Kewaunee
Nuclear Plant on Lake Michigan, and the J J* Pullhim plants in Wisconsin (ASCE, 1982;
Ray et al., 1976).
• Testing of air bubble barriers in conjunction with other behavior barriers was performed
in 1986-1987 at the Central Hudson Gas and Bectric's Roseton Generating Station in New
York (EPRI, 1988) and tile Pickering Nuclear Generating Station (EPRI, 1989a; Patrick,
et al., 1988).
• Laboratory testing was performed at the University of Maryland's Horn Point Laboratory
using varying water velocities and turbidity levels on estuarine species (EPRI 1985 and
EPRI 1986).
• It is not known whether any facilities are currently using this technology.
RESEARCH/OPERATION FINDINGS:
• Although not currently considered a reliable fish deterrent barrier, air bubble barriers
have achieved limited success. In general, the barrier is more effective with schools of
fish man with individuals.
• Ah- bubble barrier effectiveness depends largely on die temporal and spacial variability of
the dnmiigmt species near the intake structures.
• Other factors that influence effectiveness include water temperature, light intensity, and
water velocity (ASCE, 1982; EPRI, 1989; EPRI, 1989a; EPRI, 1988; EPRI 1985; Chow
et al., 1981; ASCE, 1982; Hadderingh, 1979; Ray, et al., 1976).
• Horn Laboratory (U. of Maryland) found air bubble barriers ineffective hi deterring all
taxa during daytime or night, in high or low turbidity (low turbidity at 39 to 45 NTU and
high turbidity at 102-138 NTU), or at various temperatures (EPRI, 1989).
air bubble barriers with lights and/or pneumatic guns also showed limited
success. At the Pickering Nuclear Generating Station (1985-1986) and the Central
Hudson Gas and Electric's Roseton Generating Station (1986-87), the combination of
these technologies was ineffective (EPRI, 1989). In combination with lights, species-
specific ah- bubble barrier successes were noted at Horn Point Laboratory (EPRI, 1989).
Nanticoke results of tests conducted with alewife, rainbow smelt, and gizzard shad were
not published (EPRI, 1985).
A-59
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DESIGN CONSIDERATIONS:
• Bubble cunains must extend all die way to the bottom of die water column to prevent fish
from passing through gaps in and around the barrier.
• Most test systems are designed with spacing between bubble outlets of 1 to 5 inches.
Installation and location requirements for the systems are site-specific.
• An example design from me Pickering Generating Station in Ontario includes paired
control and test structures located 78 meters offshore at die end of the '"t3^* ^anai Each
structure is 9 meters wide and gT>*nffc about 6 meters dirough die entire water column.
• The air bubble curtain at Central Hudson Gas and Hectric's Roseton Generating Station
was assembled yyfag a Bio-Weve diffuser hose manufactured by Schramm, Inc. The air
bubble curtain is made up of 15-foot sections of hose made of 5.7 cm. (2.25 in.) flexible
woven polyester fiber hose surrounded by rigid polyethylene (0.95 cm, 0.38 in). Pellets
between die inner distributer and outer diffuser provide weight to limit lateral diffusion
and counteract buoyancy. The bubble size is 0.16 cm (0.06 in.) in diameter or smaller.
The hose sections employed in the Roseton ah* bubble curtain required approximately 7.6
cubic meters per minute (270 cubic feet per minute) of ah*. Two compressors were used
to allow greater control of the air flow (EPRI, 1988).
ADVANTAGES:
• Bubble curtains are relatively easy to design and install at low cost.
• Behavioral barriers do not require physical handling of fish.
LIMITATIONS:
• Field applications of air bubble curtains have generally been unsuccessful, and results
have been inconsistent (EPRI, 1989; EPRI, 1985; Chow et al., 1981; ASCE, 1982;
Hadderingh, 1979).
• Each system must be designed to fit a she-specific intake structure.
ASCE. Design of Water Intake Structures for Fish Protection. American Society of Civil
Engineers (ASCE). pp. 69-73. 1982.
Chow, W., Ishwar P Murarka, Robert W. Brocksen. 'Electric Power Research Institute,
Entrainment and Impingement in Power Plant Cooling Systems." Journal of the Water Pollution
Control Federation. Volume 53, Number 6. June 1981.
Electric Power Research Institute. Field Testing of Behavioral Barriers for Fish Exclusion at
Cooling-Water Intake Systems: Central Hudson Gas and Electric Company. Rosaon Generating
Station. September 1988.
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Electric Power Research infinite Field Testing of Behavioral Barriers for Fish Exclusion at
Cooling-Water InHfrff Systems* Qntano Hvdro Pickering Nuclear Generating Station. March
1989a.
Electric Power Research institute (EPRI). Inmire Research Facilities Manual. Prepared by
Lawler, Matusky and Skelly Engineers and Ontario Hydro. 1985.
Electric Power Research Institute (EPRI). Intake Technologies. March 1989.
Hadderingh, R. H. 'Fish Intake Mortality at Power Stations: the Problem and Its Remedy.'
Netherlands Hvdrobiologieal Bulletin. 13(2-3), 83-93. 1979.
Patrick, P.H., R.S. McKinley, and W.C. Micheletti. Field Testing of Behavioral Barriers for
Cooling Water Intalre Structures—Test Site 1—Pickering Nuclear Generating Station. 1985/86.
Ray, S.S., RJL. Snipes, and D. A Tomljanovich. "A State-of-The-Art Report on Intake
Technologies/ TVA PRS-16 and EPA 600/7-76-020. October 1976.
U.S. EPA. Development Document for Best Technology Available for Location. Design.
Construction and Caoacitv of Cnoline Water Intake Structures far Mint
Environmental Impacts. EPA 440/1-76/015-a. 1976.
ADDITIONAL
Bibko, P.N., L. Wirtenan, and P.E. Jueser. 'Preliminary Studies on the Effects of Air Bubbles
and Intense Illumination on the Swimming Behavior of the Striped Bass (Morone saxatilis)."
Second Workshop on Entrainment and Intake Screening. Johns Hopkins University 1974 pp
293-304.
Grotbeck, L.M. 'Evaluation of an Air Curtain as a Fish Deterrent Device at the Prairie Island
Nuclear Generating Plant Cooling Water Intake." Northern States Power (NSP), 1975 Annual
Report, Environmental Monitoring and Ecological Studies Program, Prairie Island Nuclear
Generating Plant, Vol. H. 1975. pp 2.8-1 to 2.8-25.
Hocutt, C.H. •Behavioral Barriers and Guidance Systems." In Power Plants: Effects on Fish
and Shellfisfr Pehavjgr, C.H. Hocutt, J.R. Stauffer, Jr., J. Edinger, L. Hall, Jr., and R. Morgan,
n (eds.). New York, NY. Academic Press. 1980. pp. 183-205.
Patrick, P.H., A.E. Christie, D. Sager, C. Hocutt, and J. Stauffer, Jr. "Responses of Fish to a
Strobe Light/Air Bubble Barrier." Fisheries Research. 3!lS7-l72. 1985.
Sager, D.R., CM. Hocutt, and J.R. Stauffer, Jr. " Estuarine Fish Responses to Strobe Light,
Bubble Curtains, and Strobe Light/Bubble-Curtain Combinations as Influenced by Water Flow
Rate and Flash Frequencies." Fisheries Research. Vol. 5. 1987. pp. 383-399.
A-61
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FISH DIVERSION OR AVOIDANCE
SYSTEMS
FACT SHEET NO. 21
ELECTRICAL BARRIERS
DESCRIPTION:
Electrical barriers (sometimes called "electric screens") consist of a series of immersed
electrodes and ground wires mat generate an electric field (see figure below). As the fish pass
into the electric field, a voltage difference occurs through their body between the head and the
tail creating a flight reaction in the fish (HaHHeringh 1979). The electric barrier may consist
of a graduated electrical field created by successive pairs of electrodes with progressively high
voltage. An alternative configuration may have two rows of alternate electrodes (ASCE,
1982).
Frigring information on the study and use of electrical barriers indicates mat, in general,
electrical barriers do not provide the performance, consistency, or reliability that is needed in
diverting fish and other organisms away from cooling water intake structures. In most cases,
electrical barriers have been abandoned as a viable fish diversion option.
flfv. •-*
Electrical Barrier Configuration (EPA, 1976)
A-62
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• The Millstone Nuclear Power Station in Waterford, Connecticut, tested electrical barriers
from 1973 to 1975, and the Pickering Generating Station in Ontario tested them from
1976 to 1977 (EPRI, 1985). The literature cites additional studies performed in the
Pacific Northwest and Idaho and the use of this technology at intakes hi Indiana (Northern
Indiana Public Service Company's Michigan City Plant), Connecticut (CT Yankee Atomic
Power Plant), and New York (EPA, 1976; Ray et al., 1976).
• The U.S. Fish and Wildlife Service tested electric barriers for a period of 15 years until
1965 to screen and divert upstream migrant fish (EPA, 1976). Facilities abroad with
electrical barriers in use include one hi the Soviet Union and two Dutch facilities: the
Amer Power Station at Geertniidenberg and the Maas Power Station at Buggenum.
• The Dutch State Institute for Fishery Research (RTVO) has been testing fish behavior in
electric fields since 1978 (Hadderingh, 1979). The Holyoke dam and canal on the
Cffnnfffftiff"* River is reported to have tested electrical barriers hi the summer and fall of
1987 to modify the downstream movement of adult and juvenile American Shad (EPRI,
1989).
RESEARCH/OPERATION FINDINGS:
• Pulsed current has been found to be most effective for fish guidance and diversion and for
power requirements (Hanson, 1977).
• Behavioral responses vary among species and size of fish. Therefore, the required
voltage, pulse frequency, and duration differ for individual fish (Hanson, 1977; EPA,
1976).
• Guidance efficiencies of 68 percent have been reported hi large-scale laboratory
experiments using fingerling salmon. Guidance efficiency for salmonid was found to
decrease as the water velocity increased above 15 rmtifiHtm per second (cm/sec)
(Trefethen, 1955, hi Hanson, 1977).
• Adult salmon migrating upstream respond to the barrier by jumping violently back after
entering the electric field and retreating several feet downstream. After attempting to pass
the barrier several times and sustaining shocks, the fish then approach more slowly and
typically follow the line of the electric field to a fish bypass or handling device. If the
fish are stunned by the electricity, they are carried away from the intake by the current
(EPA, 1976).
DESIGN CONSIDERATIONS:
Important design considerations presented hi the available literature for electrical barriers include
the following:
• Spacing of electrodes
• Voltage applied
• Pulse frequency
A-63
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• Pulse duration
• Conductivity of die water.
The following range of design information was taken from available information on actual
operating conditions at several plants and testing facilities in the Pacific Northwest, Idaho,
California, Indiana, and New York (EPA, 1976):
Source voltages from 60 to 900 volts
Pulse frequencies of 1 to 10 pulses per sgcr>nri or continuous
Pulse
-------
ASCE. Design of Watpr Tmake Stnictnres for Fish Protection. American Society of Civil
Engineers. 1982.
EPRI. Intake Research Facilities Manual. Prepared by Lawler, Matusky & Skelly Engineers,
Pearl River, for Electric Power Research Institute. EPRI CS-3976. May 1985.
EPRI. Tmafai Technologies; Research Status. Prepared by Lawler, Matusky & Skelly
Engineers, Pearl River, for Electric Power Research Institute. EPRI GS-6293. March 1989.
Hadderingh, RJL "Fish Intake Mortality at Power Stations, the Problem and Its Remedy."
N.V. gama Amheem, Netherlands. Hydrologieal Bulletin 13(2-3) (1979): 83-93.
Hanson, CJL, et al. "Entrapment and Impingement of Fishes by Power Plant Cooling Water
Tntafajg- An Overview." Marine Fisheries Review. October 1977.
Ray, S.S., R.L. Snipes, and D.A. Tomljanovich. A State-of-me-Art Report on Intake
Technologies. Prepared for Office of Energy, Minerals, and Industry, Office of Research and
Development. U.S. Environmental Protection Agency, Washington, D.C. by the Tennessee
Valley Authority. EPA 600/7-76-020. October 1976.
U S EPA Development Document for Best Technology Available for the Location. Desipi.
Capacity of Cooling Water Intake Structures for Minimizing Adverse
Environmental Impact. U.S. Environmental Protection Agency, Effluent Guidelines Division,
Office of Water and Hazardous Materials. April 1976.
ADDITIONAL REFERENCES:
Applegate, V.C., P.T. Macy, and V.E. Harris. "Selected Bibliography on the Applications of
Electricity in Fishery Science." U.S. Fish Wildlife Service. Sec. Sei. Ren. Fish. 127 (1954):
55p.
Bates, D.W. The Horizontal Traveling Screen. In FX. Parker and P.A. Krenkel (Editors),
Engineering Aspects of Thermal Pollution. Vanderbilt University Press. Nashville, TN. 1969.
Elliot, F.E. "On the Status of Electric Fishing." J. Mar. Technol. Soc. 4. 1970. p. 58-60.
Holmes, H.B. "History, Development, and Problems of Electric Fish Screens." U.S. Fish
Wildl. Serv. Spec. Sci. Rep. 53. 1948. p. 62.
Hyman, A.M., W.H. Mowbray, and S.B. Safla. The Effects of Two Electrical Barriers on the
Entrainment of Fish at a Freshwater Nuclgar Power Plant. Symposium by Fisheries y*^ Energy
Production. 1974.
Maxwell, W.A. "Fish Diversion for Electrical Generating Station Cooling Systems a State-of-the-
Art Report." Southern Nuclear Engineering, Inc. Report SNE-123. NUS Corporation. Dunedin,
FL. 1973. 78p.
A-65
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I Pugh, J.R. "Effect of Certain Electrical Parameters and Water Resistivities on Mortality of
Fingerling Silver Saloon/ U.S. Fish Wildl. Serv. Fish Bull. 62. 1962. p. 223-234.
Pugh, JJL, G.E. Monan, and J.R. Smith. "Effect of Water Velocity on the Fish Guiding
Effectiveness of an Electric Field." Fish-Passage Res. Prog. U.S. Bur. Commer. Fish. Seattle,
Wash. Review of Progress, Vol. m. 1964. p. 6.
Stone and Webster Engineering Corp. "Fast Progress Report Indian Point Flume Study."
Consolidated Edison Company Report. New York, NY. 197S.
Texas Utilities Generating Co. "Intake Systems." In ^"""""nchff pejajEe_Sisani Electric Station
Envimninemal Report Operating License Stage. TX Utfl. Gen. Co. Report. Dallas, TX. 1979.
Trefethen, P.S. "Exploratory Experiments in Guiding Salmon Fingeriings by a Narrow D.C.
Electric Field." U.S. Fish Wildl. Serv. Snee. Sei. Ren. 158. 1955. p. 425.
Van Drevelt, T., and J.F. De Bakker. "Electrical Fish Barriers of the Maas Power Plant at
Buggenum." Eleetrotechniek 40. 1962. p. 257-276.
Vibert, R. "Applications of Electricity of Inland Fishery Biology and Management. In R. Vibert
(Editor), Fishing with Electricity. Published for F.A.O. by Fishing News (Books) Ltd. London.
1967. 276p.
A-66
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FISH DIVERSION OR AVOIDANCE
SYSTEMS
FACT SHEET NO. 22
LIGHT BARKIEBS
DESCRIPTION:
Light barriers consist of controlled application of strobe lights or mercury vapor lights to
guide fish away from cooling water intakes or deflect their natural migration patterns.
Researchers have noted mat light is very important to visual orientation of fish. However, the
response to ijpfa* barriers is species dependent; some fish are ar**?****** to light while others
avoid it Therefore, the use of light barriers has generally not proved successful (Hadderingh,
1979; ASCE, 1982, EPA 1976; EPRI, 1985; EPRI, 1989; McKinley and Patrick, 1988; Ray
et al., 1976).
TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Available literature indicated mat no light barriers are currently in use, but several
facilities have tested the technology.
• Test sites include Ontario Hydro's Pickering Nuclear Generating Station (Patrick, et al.,
1988; EPRI, 1989a); the Central Hudson Gas and Electric Rosexon Station (EPRI, 1988);
Seton Hydroelectric Station in British Columbia; Consumers Power Company; the
Holyoke Dam and Canal on the Connecticut River; the Ludington pumped storage station
on Lake Michigan; the Wanapum Dam on the Columbia River; Wapatox Canal Fish
Screening Facility on the Naches River; the University of Iowa and the University of
Washington; the York Haven Dam, Susquehanna River; the Horn Point Laboratory; and
Lakeside Engineering (EPRI, 1987; EPRI, 1989; McKinley and Patrick, 1988; Taft, et
al., 1988).
RESEARCH/OPERATION FINDINGS:
Statistical data on fish barrier studies show that results are inconsistent at best. Most
researchers found mat the light barriers are ineffective in deterring fish from entering
water intakes (Hadderingh, 1979; ASCE, 1982; EPA 1976; EPRI, 1985; EPRI, 1989;
McKinley and Patrick, 1988; Ray et al., 1976).
EPRI 1987 data show mat strobe lights may be more effective as fish barriers than
mercury lights. However, it is generally accepted mat the effectiveness of light barriers is
species dependent (ASCE, 1982; Hadderingh, 1979; EPRI, 1985; EPRI, 1989).
At Consumers Power Company, Ludington pumped storage station, Wapatox Canal,
University of Washington, and University of Iowa (EPRI reports dated 1987 and 1989),
fish were attracted to mercury lights. However, other data showed mat mercury lights
elicited no response hi fish or repelled mem (at York Haven Dam on the Susquehanna
River, from EPRI 1989).
Data from the Wapatox Canal showed no difference in results for studies conducted at
night versus daytime.
A-67
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• At the Ludington pimped storage station on Lake Michigan, die lights in combination
with a fishp'ilsy (acoustic device) had no effect on fish deterrence (EPRI 1987). At
Consumers Power Company, a study showed mat strobe lights were generally more
effective man a fishpulser. Other data on the effectiveness of a combination of behavioral
barriers were generally Tncnnsistftnt
DESIGN CONSIDERATIONS:
• Light barriers are inexpensive to design, operate, and maintain However, the species
distribution and fish response at a particular location must be evaluated in a pilot
demonstration to select the optimum design.
• The study at Horn Laboratory evaluated the effect of turbidity and velocity on fish
response to strobe lights. The lights elicited a response in 8 to 100 percent of the white
perch, spot, and Atlantic menhaden with greatest effects found at flash rates of 300/min
and lower flow rates. Turbidity also affected the strobe light effectiveness with the lowest
avoidance (9 percent) in dear water and highest avoidance (81 percent) in turbid water.
ADVANTAGES:
• Light barrier systems are inexpensive to install, operate, and maintain compared to me
total cost of a steam electric power plant
• Behavioral barriers do not require physical handling of the fish.
LIMITATIONS:
• Compared to mechanical fish barriers, light is soil generally considered a relatively
ineffective fish barrier.
REFERENCES:
ASCE. Design of Water Intake Structures for Fish Protection. American Society of Civil
Engineers. 1982. pp. 69-73.
EPRI. Field Testing of Behavioral Barriers for Fish Exclusion at Cooling-Water Infi^g SYfftf TKi
Central Hudson Gas and Electric Company. Roseton Generating Station. Electric Power Research
Institute. September 1988.
EPRI. Reid Testing of Behavioral Barriers for Fish Exclusion at Cooling-Water Intake Systems:
Ontario Hydro Pickering N.ucj£ar Generating Station. Electric Power Research Institute. March
1989a.
EPRL Intake Research Facilities Manual. Prepared by Lawler, Matusky and Skelly Engineers
and Ontario Hydro for Electric Power Research Institute. 1985.
EPRI. Intake Technologies. Electric Power Research Institute. March 1989.
A-68
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Hadderingh, R. H. "Fish Intake Mortality at Power Stations: the Problem and Its Remedy."
Netherlands Hvdrobiological Bulletin. 13(2-3), 83-93. 1979.
McKinley, R.S. and P.H. Patrick. "Use of Behavioral Stimuli to Divert Sockeye Salmon Smolts
at the Seton Hydro-Electric Station, British Columbia" from the Electric Power Research Institute.
Proceedings: Fish Protection at Steam and Hydroelectric Power Plants. March 1988.
Patrick, P.H., R.S. McKinley, and W.C. Micheletti. "Field Testing of Behavioral Barriers for
Cooling Water Intake Structures—Test She 1—Pickering Nuclear Generating Station, 1985/86," in
EPRI Proppcdjngs! Fish Protection at Steam and HvdroeJpctricPpwer Plants. March 1988.
Ray, S.S., R.L. Snipes, and D. A Tomljanovich, "A State-of-The-Art Report on Intake
Technologies,* TVA PRS-16 and EPA 600/7-76-020. October 1976.
Taft, E.P, J. K. Downing, and C. W. Sullivan. "Laboratory and Field Evaluations of Fish
Protection Systems tor Use at Hydroelectric Plants: Study Update." in EPRI Proceedings: Fish
at Stffarn and Hydroelectric Power Plants. March 1988.
U.S. EPA. Development Document for Best Technology Available for Location. Design.
Construction and Capacity of Cooling Water Intalce Structures for Minimizing Adverse
Environmental Impacts. EPA 440/l-76/01S-a. 1976.
ADDITIONAL REFERENCES:
Haymes, G.T., PJL Patrick, and LJ. Onisto. "Attraction of Fish to Mercury Vapour Light and
Its Application in a Generating Station Forebay." Int. Revue Ges. Hvdrobiological. 69:867-876.
1984.
Hocutt, C.H. "Behavioral Barriers and Guidance Systems." In Power Plants: Effects on Fish
and Shellfish Behavior. C.H. Hocutt, J.R. Stauffer, Jr., J. Edinger, L. Hall, Jr., and R. Morgan,
D (Editors). New York, NY. Academic Press. 1980. pp. 183-205.
Mclninch, S.P., and C.H. Hocutt. "Effects of Turbidity on Estuarine Fish Response to Strobe
Lights." Journal of Applied Ichthyology. Vol. 3. 1987. pp. 97-105.
Patrick, P.H. Responses of Alewife and G^rani Shad to Flashing Light. Toronto Canada*
Ontario Hydro Research Division. February 1983. 82-442-k.
Patrick, P.H., A.E. Christie, D. Sager, C. Hocutt, and J. Stauffer, Jr. "Responses of Fish to a
Strobe Light/Air Bubble Barrier." Fisheries Research. 3;1S7-17T 1985.
Patrick, P.H., and G.L. Vascotto. "Response of Fish to Light." In Proceedings of the Workshop
of Advanced Int^g Technology. 1981. pp. 252-260.
Sager, D.R., C.H. Hocutt, and J.R. Stauffer, Jr. " Estuarine Fish Responses to Strobe Light,
Bubble Curtains, and Strobe Light/Bubble-Curtain Combinations as Influenced by Water Flow
Rate and Flash Frequencies." Fisheries Research, Vol. 5. 1987. pp. 383-399.
A-69
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FISH DIVERSION OR AVOIDANCE
SYSTEMS
FACT SHEET NO. 23
SOUND BARRIERS
DESCRIPTION:
Sound barriers are non-contact barriers that rely on mechanical or electronic equipment that
rates various sound patterns to elicit avoidance responses in fish. Acoustic barriers are
to deter *jy** from fntf ing industrial water «"tair«e and power plant turbines.
Historically, the most widely-used acoustical barrier is a pneumatic air gun or "popper." The
pneumatic ah* gun is a modified seismic device which produces high-amplitude, low-frequency
sounds to ffxcludf fish. Closely related devices include "fishdrones" and "fishpulsers" (also
called •hammers"). The fishdrone produces a wider range of sound frequencies and
at**plitudfts **"**> the popper. The fishpulsw produces a repetitive sharp hammering snuittf of
low-frequency and high-amplitude. Bom instruments have limited effectiveness in the field
(EPRI, 1985; EPRI, 1989; Hanson, et al., 1977; EPA, 1976; Taft, et al., 1988; ASCE,
1982).
Prior to 1986, researchers were unable to demonstrate or apply acoustic barriers as fish
deterrents, even though fish studies showed mat fish respond to sound, because the response
varies as a function of fish species, age, and size as well as environmental factors at specific
locations. Fish may also •«•«•«•«*» to the sound patterns used (EPA, 1976; Taft et al., 1988;
EPRI, 1985; Ray et al., 1976; ******«&_ 1979; Hanson et al., 1977; ASCE, 1982).
Since about 1989, the application of highly refined sound generation equipment originally
developed for military use (e.g., sonar in submarines) has greatly advanced acoustic barrier
technology. This technology has the ability to generate a wide array of frequencies, patterns,
and volumes, which are monitored and controlled by computer. Video and computer
monitoring provide immediate feedback on the effectiveness of an experimental sound pattern
at a given location. In a particular environment, background sounds can be accounted for,
target fish species or fish populations can quickly be characterized, and the most effective
sound pattern can be selected (Menezes, et al., 1991; Sonalysts, Inc.).
TESTING FACILITIES AND/OR FACILITIES WITH TECHNOLOGY IN USE:
• No fishpulsers ?"d pneumatic air guns are currently in ws** at water intakes.
Research facilities mat have recently completed studies or have on-going testing involving
fishpulsers or pneumatic air guns include Consumers Power Company at Ludington
pumped storage site on Lake Michigan; Nova Scotia Power; the Hells Gate Hydroelectric
Station on the Black River; Southern California Edison Company at Santa Cruz Harbor on
the Pacific Ocean; the Annapolis Generating Station on the Bay of Fundy; Ontario
Hydro's Pickering Nuclear Generating station; the Roseton Generating Station, the Central
Hudson Gas and Electric Company; Seton Hydroelectric Station, British Columbia;
Empire State Electric Energy Research Corporation; .TV Corporation (Cleveland Steel
Works) on the Cuyahoga River in Ohio; Surry Powe .--lam in Virginia; New York
Power Authority's Indian Point Nuclear Generating Station Unit 3; and the U.S. Army
Corps of Engineers on the Savannah River (EPRI, 1985; EPRI, 1989; EPRI. 1988; and
Taft, et al., 1988).
A-70
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FISH DIVERSION OR AVOIDANCE
SYSTEMS
FACT KHKKT NO. 23
SOUND BARRIERS
DESCRIPTION:
jgnmiH barriers are non-contact barriers ***** rely on mechanical or electronic equipment that
generates various sound patterns to elicit avoidance responses in fish. Acoustic barriers are
used to deter fiyh from fntwing industrial water fatfafra* gad power plant turbines.
Historically, the T**^ widely-used acoustical barrier is a pneumatic air gun or "popper." The
pneumatic air gun is a modified seismic device which produces high-amplitude, low-frequency
sounds to exclude fish. Closely related devices include "fishdrones" and "fishpulsers" (also
called "hammers"). The fishdrone produces a wider range of sound frequencies and
amplitudes man the popper. The fishpulser produces a repetitive sharp hammering sound of
low-frequency and high-amplitude. Both instruments have lunitaH effectiveness in the field
(EPRI, 1985; EPRI, 1989; Hanson, et al., 1977; EPA, 1976; Taft, et al., 1988; ASCE,
1982).
Prior to 1986, researchers were unable to demonstrate or apply acoustic barriers as fish
deterrents, even though fish studies showed that fish respond to sound, because the response
varies as a function offish species, age, and size as well as environmental factors at specific
locations. Fish may also aTtimatf to the sound patterns used (EPA, 1976; Taft et al., 1988;
EPRI, 1985; Ray et al., 1976; Hadderingh, 1979; Hanson et al., 1977; ASCE, 1982).
Since about 1989, the application of highly refined sound generation equipment originally
developed for military use (e.g., sonar in submarines) has greatly advanced acoustic barrier
technology. This technology has the ability to generate a wide array of frequencies, patterns,
and volumes, which are monitored and controlled by computer. Video and computer
monitoring provide immediate feedback on the effectiveness of an experimental sound pattern
at a given location. In a particular environment, background sounds can be accounted for,
target fish species or fish populations can quickly be characterized, and the most effective
sound pattern can be selected (Menezes, et al., 1991; Sonalysts, Inc.).
TURBINE GENERATORS
oooo,,0000 O O
_- BAH HACK
RSHGATE
TRANSDUCERS
FOREBAY
NORTH
Electronic FishStartle Component Locations
A-70
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TESTING FACILITIES AND/OR FACILITIES WITH TECHNOLOGY IN USE:
• No fishpulsets ?"d pneumatic air guns are currently in use at water intakes.
• Research facilities that have recently completed studies or have on-going testing involving
fishpulsers or pneumatic air guns include Consumers Power Company at Ludington
pumped storage site on Lake Michigan; Nova Scotia Power; the Hells Gate Hydroelectric
Station on the Black River; Southern California Edison Company at Santa Cruz Harbor on
the Pacific Ocean; the Annapolis Generating Station on the Bay of Fundy; Ontario
Hydro's Pickering Nuclear Generating station; the Roseton Generating Station, the Central
Hudson Gas and Electric Company; Seton Hydroelectric Station, British Columbia;
Empire State Electric Energy Research Corporation; LTV Corporation (Cleveland Steel
Works) on the Cuyaboga River in Ohio; Surry Power Plant in Virginia; New York
Power Authority's Indian Point Nuclear Generating Station Unit 3; and the U.S. Army
Corps of Engineers on the Savannah River (EPRI, 1985; EPRI, 1989; EPRI, 1988; and
Taft, et al., 1988).
• Updated acoustic technology developed by Sonalysts, Inc. has been applied at the James
A. Fitzpatrick Nuclear Power Plant in New York on Lake Ontario; the Boston Harbor in
Massachusetts; the Vernon Hydroelectric plant on the Connecticut River (New England
Power Company, 1993; Menezes, et al., 1991; personal communication with Sonalysts,
Inc., by SAIC, 1993); and in a quarry hi Verplank, New York Punning, et al., 1993).
RESEARCH/OPERATION FINDINGS:
• Most pre-1976 research was related to fish response to sound ratter than on field
applications of sound barriers (EPA, 1976; Ray et al., 1976; Uziel, 1980; Hanson, et al.,
1977).
• Before 1986, no acoustic barriers were deemed reliable for field use. Since 1986, several
facilities have tried to use pneumatic poppers with limited successes. Even in combination
with light barriers and air bubble barriers, poppers and fishpulsets were ineffective for
most intakes (Taft and Downing, 1988; EPRI, 198S; Patrick, et al., 1988; EPRI, 1989;
EPRI, 1988; Taft, et al., 1988; McKinley and Patrick, 1988; Chow, 1981).
• A 1991 full-scale 4-month demonstration at the James A. FitzPatrick (JAF) Nuclear
Power Plant in New York on Lake Ontario showed mat the Sonalysts. Inc. FishStartle
System reduced alewife impingement by 87 percent as compared to a control power plant
located 1 mile away. (Ross, et al., 1993; Menezes, et al., 1991). JAF experienced a 96
percent reduction compared to fish impingement when the acoustic system was not in use.
A 1993 3-month test of the system at JAF was reported to be successful (Menezes et al.,
1991; SAIC personal communication with M. Curtin of Sonalysts, Inc.), but details of the
study are not yet published.
• During marine construction of Boston's third Harbor Tunnel in 1992, the Sonalysts, Inc.
FishStartle System was used to prevent shad, blueback herring, and alewives from
entering underwater blasting areas during the fishes* annual spring migration. The
portable system was used prior to each blast to temporarily deter fish and allow periods of
blasting as necessary for the construction of the tunnel (personal communication to SAIC
from M. Curtin. Sonalysts. Inc.. September 17, 1993).
A-71
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• In fall 1992, die Sonalysts, Inc. FishStaxtle System was tested in a series of experiments
conducted at the Vernon Hydroelectric plant on the Connecticut River. Caged juvenile
shad were exposed to various acoustical signals to see which signals elicited the strongest
reactions. Successful in situ tests involved applying the signals with a transducer system
to divert juvenile shad from the forebay to a bypass pipe. Shad exhibited consistent
avoidance reactions to the signals and did not show evidence of acclimation to the source
(New England Power Company, 1993).
DESIGN CONSIDERATIONS:
• Sonalysts Inc. FishStartle system uses frequencies between 15 hertz to 130 kilohenz at
sound pressure levels ranging from 130 to 2064- decibels referenced to one micropascal
(dB/AiPa). To develop a site-specific FishStartle program, a test program using
. frequencies in the low frequency portion of the spectrum between 25 and 3300 herz were
used. Fish species tested by Sonalyst's, Inc. include white perch, striped bass, atlantic
tomcod, spottail shiner, and golden shiner (Menezes et al., 1991).
• Sonalysts' FishStartle system used fixed programming contained on Erasable
Programmable Read Only Memory (EPROM) micro circuitry. For field applications, a
system was developed using IBM PC compatible software. Sonalysts* FishStartle system
includes a power source, power amplifiers, computer controls and analyzer in a control
room, all of which are connected to a noise hydrophone in the water. The system also
uses a television monitor and camera controller mat is linked to an underwater light and
camera to count fish and evaluate then* behavior.
• One Sonalysts, Inc. system has transducers placed 5 m from the bar rack of the intake.
• At the Seton Hydroelectric Station in British Columbia, the distance from the water intake
to the fishpulser was 350 m (1150 ft); at Hells Gate, a fishpulser was installed at a
distance of 500 feet from the intake.
• The pneumatic gun evaluated at the Roseton intake had a 16.4 cubic cm (1.0 cubic inch)
chamber connected by a high pressure hose and pipe assembly to an Air Power Supply
Model APS-F2-25 air compressor. The pressure used was a line pressure of 20.7 MPa
(3000 psi) (EPRI, 1988).
ADVANTAGES:
• The pneumatic ah* gun, hammer, ««d fishpulser are easily implemented at low costs.
• Behavioral barriers do not require physical handling of the fish.
A-72
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LIMITATIONS:
• The pneumatic air gun, hammer, and fishpulser are not considered reliable.
• Sophisticated acoustic sound generating systems require relatively expensive systems,
including cameras, sound generating systems, and control systems. No cost information
is available since a permanent system has yet to be installed.
• Sound barrier systems require site-specific designs consisting of relatively high technology
equipment mat must be maintained at the she.
REFERENCES:
ASCE. Pesifn of Water Intaire Structures for Fish Protection. American Society of Civil
Engineers. New York, NY. 1982. pp. 69-73.
Chow, W., Ishwar P. Murarka, Robert W. Brocksen. Electric Power Research Institute,
Entrahment and Iimingement in Power Plant Cooling Systems. June 1981.
Dunning, DJ., Q.E. Ross, P. Geoghegan, JJ. Reichle, J. K. Menezes, and J.K. Watson.
Alewives Avoid High Frequency Sound. 1993.
EPRL Field Testing of Behavioral Barriers for Fish Exclusion at Cooling-Water Intake Systems:
Central Hudson Gas 2nd Electric Company. Roseton Generating Station. Electric Power Research
Institute. September 1988.
EPRI. Field Testing of Behavioral Barriers for Fish Exclusion at Cooling-Water Intake Systems:
Ontario Hvdro Pickering NllfIffST Generating Station. Electric Power Research Institute. March
1989a.
EPRI. Intake Research Facilities Manual. 1985. Prepared by Lawler, Matusky & Skelly
Engineers, Pearl River, for Electric Power Research Institute. EPRI CS-3976. May 1985.
EPRI. Intake Technologies! Research Status Prepared by Lawler, Matusky & Skelly
Engineers, Pearl River, for Electric Power Research Institute. EPRI GS-6293. March 1989.
Hadderingh, R. H. 'Fish Intake Mortality at Power Stations: The Problem and Its Remedy.'
Netherlands Hvdrobiolopical Bulletin. 13(2-3), 83-93, 1979.
Hanson, C. H., J.R. White, and H.W. Li. "Entrapment and Impingement of Fishes by Power
Plant Cooling Water Intakes: An Overview/ from Fisheries Review. MFR Paper 1266.
October 1977.
McKmley, R.S. and P.H. Patrick. 'Use of Behavioral Stimuli to Divert Sockeye Salmon Smolts
at the Seton Hydro-Electric Station, British Columbia." In the Electric Power Research Institute
Proceedings: Fish Protection at Steam and Hydroelectric Power Plants. March 1988.
Menezes, Stephen W. Dolat, Gary W. Tiller, and Peter J. Dolan. Sonalysts, Inc. Waterford,
Connecticut. The Electronic FishStanle System. 1991.
A-73
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New T»qgiand power Company. Effect of Ensonification on Juvenile American Shad Movement
and Behavior at Vernon Hydroelectric Station, 1992. March 1993.
Patrick, P.H., R.S. McKinley, and W.C. Micheletti. 'Field Testing of Behavioral Barriers for
Cooling Water Intake Structures—Test Site 1—Pickering Nuclear Generating Station, 1985/86."
In the Electric Power Research Institute Proceedings: Fish Protection at
Power Plants. March 1988.
Personal Communication, September 17, 1993, letter and enclosure from MJ. Curtin (Sonalysts,
Inc.) to D. Benelmouffok (SAIQ.
Ray, S.S., RJ.. Snipes, and D. A Tomljanovich. 'A State-of-the-Axt Report on Intake
Technologies." TVA PRS-16 and EPA 600/7-76-020. October 1976.
Sonalysts, Inc. "FishStartle System in Action: Acoustic Solutions to Environmental Problems"
(on video tape). 215 Parkway North, Waterford, CT 06385.
Taft, E. P., and JJC. Downing. "Comparative Assessment of Fish Protection Alternatives for
Fossil vtf Hydroelectric Facilities." In the Electric Power Research Institute Proceedings: Fish
Protection at S^eajn and Hydroelectric Power Plants. March 1988.
Taft, EJ>, J. K. Downing, and C. W. Sullivan. "Laboratory and Field Evaluations of Fish
Protection Systems for Use at Hydroelectric Plants Study Update." In the Electric Power
Research Institute's Proceedings: Fish Protection at Steam and Hydroelectric Power Plants.
March 1988.
U.S. EPA. Development Document for Best Technology Available for the Location. Design.
Construction, and Canachv of CoeAmf Water Intake Structures fhr Minirntrinp Adverce
Environmental Impact. U.S. Environmental Protection Agency, Effluent Guidelines Division,
Office of Water and Hazardous Materials. April 1976.
Uziel, Mary S., "Entrainment and Impingement at Cooling Water Intakes." Journal WPCF. Vol.
52, No.6. June 1980.
ADDITIONAL REFERENCES:
Blaxter, J.H.S., and D.E. Boss. "Startle Response in Herring: the Effect of Sound Stimulus
Frequency, Size of Fish and Selective Interference with the Acoustical-lateralis System." Journal
of the Marine Biological Association of the United Kingdom. 61:871-879. 1981.
Blaxter, JJ.S., J.A.B. Gray, and EJ. Demon. "Sound and Startle Response in Herring Shoals."
J. Mar. Biol. Ass U.K. 61:851-869. 1981.
Burdic, W.S. Underwater Acoustic System Analysis. Englewood Cliffs, New Jersey Prentice-
Hall. 1984.
Burner, CJ., and H.L. Moore. "Attempts to Guide Small Fish with Underwater Sound. "U.S.
Fish and Wildlife Service. Special Scientific Report: Fisheries No. 403. 1962. p. 29.
A-74
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C.H. HocutL "Behavioral Barriers yd Guidance Systems." In Power Plants: Effects on Fish
and Shellfish Behavior. C.H. Hocutt, J.R. Stauffer, Jr., J. Edingec, L. Hall, Jr., and R. Morgan,
D (Editors). Academic Press. New York, NY. 1980. pp. 183-205.
Empire State Electric Energy Research Corporation. "Alternative Fish Protective Techniques:
Pneumatic Guns and Rope Nets." EP-83-12. March 1984.
Fay, R.R. HffgrinF *n Invertebrates: A Psvchophvsics Data Book. Hill-Fay Associates.
Winnetka, Illinois. 1988.
Frizzell, L.A., "Biological Effects of Acoustic Cavitation." In Ultrasound Its Chemical. Physical.
and Biological* Effects. ILS. Suslick (Editor). VCH Publishers, Inc. New York. 1988. pp.
287-319.
Haymes, G.T., and P JL Patrick. "Exclusion of Adult Alewife (Alosa pseuoharengus), Using
Low-Frequency Sound for Application of Water Intakes." Can, J. Fifth- Aquatics Sci. 43:855-
862. 1986.
Michdetti, Coal Combustion Systems Division. "Fish Protection at Cooling Water Intake
Systems." FPRJ Jmm«|i September 1987.
Michdetti, Coal Combustion Systems Division. "Fish Protection at Cooling Water Intake
Systems." EPR1 Journal. September 1987.
Patrick, P.H., R.S. McKinley, A. E. Christie, and J.G. Holsapple. "Fish Protection: Sonic
Deterrents." In the EPRI Proceedings: Fish Protection at Steam and Hydroelectric Power Plants.
March 1988.
Platt, C., and A.N. Popper. "Find Structure and Function of the Ear.* In Hearing and Sound
Communication in Fishes. W.N. Tavolga, A.N. Popper and R.R. Ray (Editors). Springer-
Verlag. New York.
Ross, Q.E., D. J. Dunning, R. Thome, J. Menezes, G. W. Tiller, and J. K. Watson. Response
of Alewives to High-Frequenev Sound at a Power Plant I"fflke O" Lake Ontario 1993.
Schwarz, A.L., and G.L. Greer. "Responses of Pacific Herring, Clupea hareneus pallasi. to
Some Underwater Sounds." Can. ?. Fifth- Amiatie Sei 41:1183-1192. 1984.
Smitfa, EJ., and J.K. Andersen. "Attempts to Alleviate Fish Losses from Allegheny Reservoir,
Pennsylvania and New York, Using Acoustic." North American Journal of Fisheries
Management, vol 4(3), 1984. pp. 300-307.
Thome, tLE. "Assessment of Population Density by Hydroacoustics." In Journal of Biological
Oceanography. Vol.2. 1983. pp. 252-262.
A-75
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FISH DIVERSION OR AVOIDANCE
SYSTEMS
FACT SHEET NO. 24
CABLE AND CHAIN BARRIERS
DESCRIPTION:
Cable «™* <**«g"i barriers
called
chain curtains') consist of cables or
chains suspended vertically in front of the cooling water intake (see figure below). These
systems are <*«««£"«*< to take advantage of fish behavior and the tendency of fish to avoid
objects moving through the water (Ray et al., 1976). This curtain can be moved horizontally
through the water to create turbulent flows, which fish will sense and avoid.
Conclusions in most of the testing conducted to date are that the technology shows little
divertin fish at coolin water intakes.
promise for diverting fish at cooling water intakes.
Offshore Intake With Hanging Chain Barriers (Mussalli et al., 1980)
A-76
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TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Testing of a chain curtain was performed from 1978 to 1979 at the Namioke Thermal
Generating Station in Ontario, Canada (EPRI, 1985). No other testing facilities were
luCDtulfiu ID QIC*' llt
FINDINGS:
• Experimental results have shown mat if the chain barrier is moved horizontally through
the water, fish diversion efficiency is unproved (Hadderingh, 1979).
• The effectiveness of chain barriers may be dependent upon water flow, depth of the water
intake area, and turbidity of the water (Hadderingh, 1979).
• A chain barrier tested by model was shown to be moderately effective in warm water and
ineffective in cold water (ASCE, 1982).
• At a plant on the Hudson River, cable and chain barriers were shown to be ineffective
altogether (ASCE, 1982).
• In laboratory tests performed by the University of Washington and the Fisheries Research
Board in Canada, chain barriers were shown to be more effective in the daylight than at
nightime. Maximum efficiencies of 94 f*4 71 percent in day an|1 night applications,
respectively, were obtained hi Canadian studies using migrating Sockeye salmon with
chains spaced at 5 centimeters and hung at a 45 degree angle to the flow. These tests
were performed hi both still water and moving water, at different angles to the flow, and
at several different spacing combinations of chains (Ray et al., 1976).
DESIGN CONSIDERATIONS:
• A model facility to test the cable and chain barrier installed an array of 3/16 inch chain
lengths each 3 feet long and spaced on 2-inch centers. The actual spaces between the
chain were 1.25 inches (Mussalli, 1980).
• Operational problems due to the wave action, debris, and icing should be considered
(Mussalli, 1980).
• Chains should be placed far enough away from the intake structure to
entanglement and to allow flow into the structure should the chains clog with debris or ice
(Mussalli, 1980).
ADVANTAGES:
• Cable and chain barriers are relatively low hi cost and maintenance free if designed
properly.
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LIMITATIONS:
• Cable and chain barriers are less effective at night
• Cable yd <*»«»« barriers do not exclude all fish.
REFERENCES:
EPRL ln*aJf». **ffjffarrtl facilities Manual. Prepared by Lawler, Matusky & Skelly Engineers,
Pearl River, for Electric Power Research Institute. EPRI CS-3976. May 1985.
Hadderingh, RJL "Fish Intake Mortality at Power Stations, die Problem and Its Remedy."
N.V. Kema, Arnheem, Netherlands. Hvdmlogieal Bulletin 13(2-3) (1979): 83-93.
Mussalli, Y.G., E.P Taft m, and J. Larson. "Offchore Water Intakes Designed to Protect Fish.*
Journal of the Hydraulics Pi vision Proceedings of the American Society of Civil Engineers. Vol.
106 Hy 11 (1980): 1885-1901.
Ray, S.S., R.L, Snipes, a™1 D.A. Tomljanovich. A State-of-the-Art Report on Intake
Technologies. Prepared for Office of Energy, Minerals, and Industry, Office of Research and
Development. U.S. Environmental Protection Agency, Washington, DC by the Tennessee Valley
Authority. EPA 600/7-76X120. October 1976.
ADDITIONAL PKJ^MBMCRB?
Brett, JJL, and DJ. Alderdice. "Lakelse River Experiments on Guiding Sockey and Coho
Salmon Fingerlings." ^*ana<^^ap_FjsJi- Res. Board. Pfot?i. Reports of Pacific Coast Stations No.
106(1956): 14-20.
Brett, J.R., D. Mackinnon, and D.F. Alderdice. "Trough Experiments on Guiding Sockey
Salmon Fingerlings." Canadian Fish. Res. Board. Progr. Reports of Pacific Coast Stations No.
99(1954): 24-27.
Foster, J.R. "Benthic Net and Chain Curtain for Fish Diversion." Presented at the Workshop on
Advanced Intake Technologies. San Diego, CA. U.S. Fish and Wildlife Service. Washington,
DC. 1981.
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FISH DIVERSION OR AVOIDANCE
SYSTEMS
FACT SHKKT NO. 25
WATER JET CURTAINS
DESCRIPTION:
Water jet curtains typically consist of a row of vertical pipes placed in front of the cooling
water intake (see figure below). Nozzles are fitted at regular intervals the length of the pipes
to produce a lateral curtain of water when operating. These jets produce a curtain of high
pressure water, which is intended to deter the fish from *«»*""g die intake area. A typical jet
curtain might have vertical pipes 3/4 inches in diamrfrr. spaced 1 foot apart with nozzles
(openings as small as 1/32 inch) spaced at 0.5 inch on center (ASCE, 1982; Mussalli, 1979).
Water jet curtains have not been used in many actual applications to date. Testing has not
shown the efficiency of the technology to be appropriate for use alone to divert fish from
cooling water intakes. However, this technology may be used in conjunction with other
technologies to provide an efficient fish diversion system.
•MM «T ftM -/
•i*. MI «xr*-u
Intake With Water Jet Curtains (Mussalli et al., 1980)
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I TESTING FACILITIES AND/OR FACILITIES USING THE TECHNOLOGY:
• Water jet curtains were tested for the Niagara Mohawk Power Corporation and Roch
Gas and Electric Corporation in die mid-seventies (Mussalli, 1977). It is not known
whether any facilities use die technology now.
RESEARCH/OPERATION FINDINGS:
• Laboratory studies have shown diat water jets widi 60 pounds per square inch (psi)
pressure from 1/32 or 1/16 inch in $**me**r nodes in a diffuser pipe oriented at a 30
degree angle to the intake structure are moderately effective in diverting fish (Mussalli,
1977).
• Studies at large-scale testing acuities have shown tiiis technology to be relatively
ineffective (ASCE, 1982).
• Tests by die U.S. Bureau of Commercial Fisheries have shown efficiencies for water jet
curtains at 60 to 80 percent under varied water pressure, array angles, and approach
systems (Ray et al., 1976).
DESIGN CONSIDERATIONS:
• For offshore intakes, vertical bars should be placed about 1 foot apart to prevent potential
blockage of the intake from accumulation of debris (Mussalli, 1977).
• Because the strength of die submerged water jet decreases rapidly, h is recommended that
two rows of closely spaced nozzles be oriented so mat they are jetting toward each other
to create an effective curtain (Mussalli, 1977).
• Consideration should be given to problems associated with icing, siltation, and wave
action (Mussalli, 1977).
• Warm water in me jets can be used to reduce die potential of frazil ice formations
(Mussalli, 1980).
ADVANTAGES:
• Water jet curtains provide me flexibility to use or not use die system during certain
periods of time, as appropriate.
LIMITATIONS:
• The water supply for the water jets must be filtered to prevent clogging of die small
nozzle openings (Mussalli, 1977).
• Maintenance is required to prevent clogging of me nozzles, particularly in a marine
environment, and may be extensive (ASCE, 1982).
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• For large facilities, die flow of water required may be ^acceptably large (ASCE, 1982;
Ray et ah, 1976).
REFERENCES:
ASCE. Design of Water IflTaKp $**»<**»« for Fish Protection. American Society of Civil
Engineers. 1982.
MussalU, Y.G., E.P Taft m, and J. Larson. "Offshore Water Intakes Designed to Protect Fish."
106 Hyll (1980): 1885-1901.
i Y.G., EP. Taft, and P. Hoffman. "Engineering Implications of New Fish Screening
Concepts." In Fourth National Workshop on Entrainment and Impingement. L.D. Jensen
(Editor), Ecological Analysts, Inc. Mdvflle, NY. Chicago, IL. December 1977.
Ray, S.S., R-L. Snipes, and D.A. Tomljanovich. A State-of-the-Art Report on Intake
Technologies. Prepared for Office of Energy, Minerals, and Industry, Office of Research and
Development. U.S. Environmental Protection Agency, Washington, DC by the Tennessee Valley
Authority. EPA 600/7-76-020. October 1976.
ADDITIONAL REFERENCES!
Stone **>A Webster ^*tlpip*?rin£ Corporation. Engineering Feasibility of Fish Behavioral Barriers.
Report prepared tor Niagara Mohawk Power Corporation and Rochester Gas & Electric Power
Corporation. 1977.
Stone and Webster Engineering Corporation. Studies to Alleviate Fish Entrapment at Power Plant
Cooling Water Intakes—Final Report. Prepared for Niagara Mohawk Power Corporation and
Rochester Gas & Electric Power Corporation. 1976.
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