BIOLOGICAL EVALUATION OF BRAYTON POINT STATION UNIT 4

ANGLED SCREEN INTAKE

Robert W. Davis , John A. Matousek, and Michael J. Skelly

Lawler, Matusky & Skelly Engineers

One Blue Hill Plaza , P. O. Box 1509

Pearl River , New York 10965

and

Mi 1 ton R. Ande rson

New England Power Service Company

25 Research Drive

Westborough , Massachusetts 01581

ABSTRACT

An 18-month (October 1984 - March 1986) biological evaluation study sponsored by

New England Power Company (NEP) was conducted at the Brayton Point Station Unit 4

angled screen intake system located on Lee River/Mount Hope 

Bay, Massachusetts , the northeast portion of Narragansett Bay. The objectives of the testing program,

which incorporated weekly sampling covering a complete diel period, were to determine (1) the numbers , species, and initial and extended survival of fish impinged

on the modified intake screens or diverted from the angled screen intake; and 

(2)

the diversion efficiency (DE) of the angled screens.

During the study period, a total of 79, 206 fish were entrapped (based on comparable

samples between angled screens and diversion flow): 18 791 from the angled screens

and 60, 415 estimated from the diversion flow. Diversion efficiency was 76. 3%. with

a corresponding impingement efficiency (I-DE) of 23. 7%. Initial survival classification of impinged and bypassed fish was conducted immediately following collection; 'extended survival observations over a 48- h period were conducted on a representative subsample of fish initially classified as live or stunned. Initial

diversion survival for all species combined was 57. 8%. Extended diversion survival

observations indicated 63. 4% survival. Initial and extended (48- h) impingement

survival was 24. 3 and 77. 7%, respectively. Total angled screen system efficiency
was 32. 4%, increasing to 55. 3% with the exclusion of bay anchovy, which constituted

41. 1% of the tota 1 entrapment.

Collection and handling mortality estimates were determined for the numerically

dominant taxa. Impingement collection and handling mortality for selected fish

taxa was not indicated by the testing procedure; diversion bypass collection and

handling mortality was observed to be species specific, with a total taxa overall

value of 24. 2% and ranging from 51. 6% for Atlantic silverside to zero for tautog.

The angled screen intake system was found to be effective, i. e., exhibited high

diversion in mitigating fish impingement. Initial and extended survival varied by

species, but in general there was a " sensiti ve" group composed of a few numeri cally

dominant taxa (mostly bay anchovy and Atlantic silverside) with calculated survival

below 25. 0% and a " hardy " group (mixed taxa dominated by winter flounder and

northern pipefish) with survival values greater than 65. 0%.

I NTRODUCT I ON

The amount of water used by industry each year, especially the nonconsumptive use

by electric utilities for condenser cooling, represents a significant portion of

the total fresh water available. In the evaluation of environmental impacts

related to power plant operation, the initial concern over nonconsumptive use of

water was with thermal discharges and their potential to alter the nearfield temperature regimes. Attention was also directed to the cooling water intakes and

their potential for entraining small planktonic organisms and entrapping larger

organisms, with subsequent impingement on the intake traveling screens.

Du ri n9 the ea rl y 1970s, pub 1 i c awa reness of the need to protect the envi ronment

res u 1 ted in the passage and imp 1 ementa t i on of the Federa 1 Water Po II ut ion Contro 

Act of 1972 (Publ ic Law 92-500) and the Clean Water Act amendments of 1977 (PL 95-

217). This legislation features sections pertaining to cooling water intakes,

notably Section 316(b) of PL 92- 500, which requires that the location, design, construction, and capacity of cooling water intake structures reflect the best technology available for minimizing adverse environmental impacts.

The incorporation of fish protection devices into the design of an intake is one

way to minimize the impact of the cooling water intake and thus achieve the goals
of Section 316(b) (1). Protective devices fall into three general categories: (1)

collection and removal, (2) deterrence (behavioral and physical barriers), and (3)

diversion (f-Q).

Vertically oriented traveling screens, the primary method for collecting and removing debris from the condenser cooling water, impinge the organism and then return

it to the receiving water following removal from the screen by means of a pressure

wash. Because these systems were designed for debris removal and not protection of

organisms, organism survival is a major problem. Several modifications to increase

intake screen survival have been tested; the best results have come from the addition of lip troughs to the screen baskets that maintain the fish in water during

the screen rotation cycle and from continuous screen rotation schedules.

Deterrence and diversion devices depend on behavior of fishes, and rely on the

ability of fish to perceive and react to an external stimulus. Deterrent devices

used with varying degrees of success are electrical barriers, air or bubble curtains, chain and net barriers, lights, and sound (1, 2-11). The two primary diversion systems that have been evaluated for impact mitigation are louvers and angled

screens.

Initial evaluation studies on the use of diversion systems at pumped cooling water

intakes closely followed studies initially conducted at hydroelectric facilities.

The idea of guiding fish to a diversion transpor~ system was first evaluated in

test flumes during the early 1970s 

). 

Results from these tests were promising, leading to the decision in 1979 to construct a full-scale demonstration angled

screen intake to permit continued evaluation under actual environmental conditions

and with normally occurring fish populations. The Empire State Electric Energy

Research Corporation (ESEERCO), a research group that comprises the New York State

electric utilities that sponsored many of the laboratory studies on angled screens,

sponsored the study at the Danskammer Point Generating Station on the Hudson River

, ). 

At approximately the same time, Niagara Mohawk Power Company incorporated an angled screen intake system at their Oswego Steam Station Unit 6 on Lake

Ontari 0 

().

In 1981 New England Power Company (NEP) proposed converting its Brayton Point Unit

4 from closed-cycle cooling to once- through cooling (

). 

Following a review of

studies conducted on several intake mitigation systems including porous dikes and

angled screens, NEP recommended an angled screen intake system incorporating modi-
fied traveling screens for Unit 4 open-cycle cooling as best technology available.

The new system went into operation in July 1984. An 18-month (October 1984 - March

1986) biological evaluation study sponsored by NEP was conducted at Unit 4 to

evaluate system effectiveness at returning, alive , the fish impinged on the angled

vertical traveling screens or diverted through the Hidrostal pump flow- induced bypass sys tem (

STUDY SITE AND UNIT 4 ANGLED SCREEN INTAKE DESCRIPTION

The Brayton Point Generating Station, located on the shore of the Lee River just

north of the confl uence wi th the Taunton Ri ver on Mount Hope Bay, Massachusetts,

in the northeast portion of Narragansett Bay, is a four-unit, fossil- fired (oil and

coal) facility with a total rated capacity of 1590 MW (Figure 1). Unit 4, completed in 1974, is a 460 MW oil- fired cycling unit. The river in the general vic in i ty of the intake is more than 500 m (1640 ft) wi de, wi th an a ve rage depth of

3 m (7. 5 ft) at mean sea level. Tidal height averages f1. 3 m (f4. 3 ft). Sal inities are generally 75-85% of normal oceanic values, averaging 27 parts per thousand

(ppt). Water temperatures range from 0 to 29Q C (32 to 84Q F).

Cooling water enters the structure through eight openings 3. 3 m (11 ft) wide by 4.

m (14 ft) high that extend from elevation - 4 m (- 18 ft) to the bottom of a skimmer wall at elevation - 2 m (-4 ft) (Figure 2). The openings are shielded by

trash racks with a bar spacing of 7. 5 cm (3 in. ) on center. Over 10 m (33 ft) into

the mouth of the screenwell, the width constricts to 12. 3 m (41 ft) approaching a

5-m- thick (5- ft) center wall that divides the structure in half. Each half is

equipped with three 3. 0-m-wide (10- ft) flush-mounted modified vertical traveling

screens set at 250 to the approaching flow. After passing through the traveling

screens, the cooling water flow exits the angled screen structure into a cooling

canal.

The design flow of 17. 28 m3/s (610 ft3/s) is drawn through the bar racks at an

average approach velocity of 15 cm/s (0. 5 ft3/s). As the structure constricts, the

design velocity increases to 30 cm/s (1. 0 ft3/s) approaching the travel ing

screens. Approximately 97% of the design flow (16. 77 m3/s (592 ft3/sJ) is drawn

through the screens; the remaining 3% (0. 51 m3/s (18 ft3/sJ) is pumped through the

fish bypass. Of the flow passing through the screens, 0. 4 m3/s (14 ft3/s) is service water used for screen cleaning. The other 16. 37 m3/s (578 ft3/s) continues
into the cooling canal, is pumped by the two circulating water pumps through the

turbine condenser, and combines with the Units 1, 2, and 3 discharge that flows

into Mount Hope Bay.

Fish entrapped in the cooling water flow either divert into the fish bypass/return

system or become impinged on the modified traveling screens (Figure 2). Impinged

fish are washed off the back of the screens by a low- pressure spray into a fish

trough that runs behind the screens and joins together at the bypass end of the

screen rows. The fish are carried along the trough and into a 35-cm (14- in. ) diameter fiberglass pipe , then to the Lee River approximately 91 m (300 ft) south of

the Unit 4 intake structure. Each screen panel is modified with a bucket to maintain the impinged fish in water as the screen rotates. The screens are designed to

allow the interchange of standard (9. 5-mm (O. 38-in. J) and fine (1. 0-mm (O. 04- in.

mesh screeni ng panel s. The fi ne mesh screens were employed from March through September 1985 for the ichthyoplankton evaluation program.

At the apex of each screenwell is a fi sh bypass (Figure 2). Each bypass has a rectangular opening 15. 2 cm (6 in. ) wide by 5. 1 m (17 ft) high that constricts to a

46-cm (18-in. ) diameter bypass pipe. The bypass slot is sized such that two

shrouded 30-cm (12-in. ) diameter screw impeller centrifugal pumps (Hidrostal Model

L12F) can induce a velocity of 30 cm/s (1. 0 ft3/s) at the slot' s entrance. The bypass velocity at the slot was scheduled to be the same as the screen approach

velocity. Flow entering either of the two separate bypasses is carried into a 46-

cm (18- in. ) diameter fiberglass pipe that branches into two 30-cm (12- in. ) diameter

pipes, then passes through the Hidrostal pumps and back into a 46-cm diameter pipe

that discharges to the Lee River at the same location as the impingement return.

DESCRIPTION OF BIOLOGICAL PROGRAM

The objectives of the testing program were to determine (1) the numbers, species,

and i ni tial and extended survi val of fi sh impi nged on the modi fied intake screens

or diverted from the angled screen intake; and (2) the diversion efficiency (DE) of

the angled screens. Impingement abundance and survival collections were conducted

simultaneously with bypass abundance and survival collections. The program incorporated weekly sampling covering a complete diel period. The bypass return system

was monitored during each impingement collection period (8- or 12- h survey) using

subsampling procedures with each subsample approximately 1 h in duration. Impinge-
ment collections were made from two 1. 5-m (5-ft) diameter built- in fiberglass collection tanks. Each tank receives the screen washings from three angled screens.

Collection tank water level was maintained at 0. 8 m (32 in. ) by means of an overflow standpipe that was surrounded by a taller, larger diameter, removable fiberglass pipe. The outer pipe was uniformally perforated with 6. 4-mm (0. 25- in. ) diameter holes to permit water drainage during sample collection. Bypass collections

were made using nets attached to a sampling port on each 46-cm (l8- in. ) fish bypass

return line. The collection nets were constructed of 6. 4-mm (0. 25- in. ) square

delta mesh netting attached to 1. 8-m (6- ft) diameter fiberglass hoops and suspended

in the water. Fish from both screenwells (north and south) were sampled simultaneously to monitor spatial distribution patterns.

The abora tory faci 1 i ty was equ i pped wi th three types of fl ow- th rough extended su rvival holding containers. Juvenile or young-of- the-year fish were held primarily

in 19- 1 (5-gal) plastic buckets. Larger fish or large numbers of individual species were held in 568- 1 (150-gal) linear polyethylene holding tanks fitted with a

central standpipe arrangement that permi tted a uniform exchange of water throughout

the water col umn and/or hol di ng nets constructed of 0. 32 cm (0. 13 in. ) square ace

mesh suspended in the cooling canal. Water was supplied to the bucket and tank

holding containers through a header system and regulated by valves to maintain

ambient conditions for the extended survival period.

Diversion efficiency (DE) of the angled screen intake system is defined as the proportion of fish entering the bypass in comparison to the number entering the

screenwell. The number of fish entering the screenwell (total entrapment, TE) is

calculated as the sum of the angled screen impingement (Screens 1-6) and the estimated number of fish diverted during the corresponding impingement period:

TE = IMP + DIV (1 )

where

IMP = impi ngement on Screens 1- 3 and 4-

DIV = estimated fish diversion in north and south bypass

Estimated diversion (DIV) was calculated by obtaining the diversion rate, DIVR

(number of fi sh diverted per hour), and mul tiplyi ng the rate by the time of the

corresponding impingement period.
LNo. fish in diversion samples DIVR = 

2: Diversion sample times (h) (2)

Therefore

DIV

- TE (3 )

Impingement efficiency (IE), the complement of DE, is defined as the proportion of

fi sh impi nged in compari son to the number enteri ng the screenwell:

IE = 1 - DE (4 )

Initial survival was determined by observing fish from the diversion flow and

impingement screenwash immediately following collection. Fish were identified

and classified (live, stunned, dead), with the classification conditions defined

as follows:

Live - swimming normally, no orientation problem

Stunned - swimming erratically, swimming on thei r side, struggl ing

Dead - no vital life signs, no body or opercular movement, no response

to gentle probi 

Initial survival was calculated by dividing the number determined to be initially

live (L) and stunned (ST) by the number initially determined to be live, stunned,

and dead (D). The initial survival formula is:

Initial survival (Sr) = ~;~:D (5 )

Extended survival (SE) observations were conducted over 48 h for the Brayton

Point Unit 4 program. Extended survival was calculated by dividing the number of

fish classified live at the end of the observation period (L48) by the total number

of fish examined for extended survival (L+ST):

Extended survival (SE) = 

( 6)

Survival for diversion and impingement was the proportion of initially live (live

and stunned) fish that survived the 48- h test period:

Survival (S) = SI x SE (7)
Total system efficiency of the angled screen system is basically a determination

of the probability that a fish entering the angled screen system will survive some

period of time after entry and diversion or impingement. The four probabilities

previously estimated - diversion efficiency (DE), impingement efficiency (IE),

diversion survival (SDIV), and impingement survival (SIMP) - can be used to

calculate the total Unit 4 angled screen system efficiency (TSE).

Let P(x) represent the probability of x, and P (x if y) represent the probability

of x given y. Then:

Diversion efficiency (DE) = Pd = P (fish is diverted)

Impingement efficiency (IE) = Pi = P (fish is impinged) = (I-DE)

Diversion survival (SDIY) = Psd (fish survives 48 h if diverted)

Impingement survival (SIMP) = Psi (fish survives 48 h if impinged)

Tota 1 sys tem effi ci ency (TSE) is defi ned as:

Pe = P (fish survives 48 h if diverted or impinged)

and can be computed from the conditional probabilities as:

Pe = (Pd x Psd)+(Pi x Psi) or TSE = (DE x SDIY) + (IE x SIMP) (8)

Thus, for each of the fish return systems, diversion or impingement, a separate

system efficiency (SE) is computed from the respective conditional probabilities,

the sums of each yielding the total system efficiency.

A fish control study was incorporated to determine collection and handling mortality associated with the diversion and impingement survival program phases. Control

fish were collected with a variety of devices from the Lee River. Prior to placement in the ho ding conta i ners, the fi sh were fi n-c 1 i pped to separate them from

abundance/survival fish collected during a regular sampling event. Fish that were

alive after 24 h were then subjected to the three test conditions. Diversion and

impingement control fish were placed in their respective collection devices and

routine sampling was conducted. Control fish not selected for either diversion or

impingement testing were left in the holding container for evaluation of finclipping mortality from mortality associated with the collection process. All fish

were held for extended survival observations (48 h).
EVALUATION PROGRAM RESULTS AND DISCUSSION

The angled screen evaluation program resulted in the collection of 57 fish species

of 36 families. Abundance, percent composition, and diversion efficiency for the

major taxa (95. 4% of the total) and total fish collected during the 18-month study

period are presented in Table 1. During the study period, 79, 206 fish were entrapped (based on comparable samples between angled screens and diversion flow):

18, 791 collected from the angled screens and 60, 415 estimated from the diversion

flow. Diversion efficiency (DE) was 76. 3%, with a corresponding impingement efficiency (1 = DE) of 23. 7% for all species combined. Exclusion of the dominant bay

anchovy, primari ly young-of-the-year coll ected wi th the fi ne mesh screens duri 

August and September 1985, increases the DE to 89. 7%. Over 93% of the total bay

anchovy entrapment , with mean total length of 2. 7 cm (1. 1 in. ) (range 1. 9 cm

(0. 3 in. )), occurred during this two-month period. The majority of the bay

anchovy during this period were of entrainable size and would have passed through

the standard mesh screens into the cool i ng canal (fl). Ni ne of the top 12 taxa

exhibited diversion efficiencies greater than 83. 2%, to a maximum of 99. 4%. Diversion efficiencies for bay anchovy, northern pipefish , and tautog were 57. 0, 52.

and 62. 2%, respectively. Diversion efficiency was 86. 7% for the other 45 fish species combined.

Initial survival (Sr) observations of 28, 186 fish collected from the diversion

flow (Table 2) ranged from 5. 6% for bay anchovy to 99. 7% for American eel. Initial

survival was 57. 8% for all taxa combined , increasing to 82. 6% with the exclusion of

bay anchovy. Extended 48-h su rvi va 1 observa t ions (SE) we re made on 9209 fi sh and

resulted in an overall , extended survival value of 63. 4%. Extended survival trends

for the major taxa were similar to initial survival and were variable among species, ranging from 0% for bay anchovy to 99. 6% for tautDg. For the top 12 taxa

the lowest survival (5) (0. 0%) was calculated for bay anchovy, followed by Atlantic

menhaden (2. 8%), butterfish (6. 6%), and Atlantic silverside (23. 2%). The remaining

taxa had survival greater than 66% (seaboard goby), ranging to 98. 8% for tautog.

Overall diversion survival was 36. 6%, increasing to 53. 2% with the exclusion of bay

anchovy. In general, the fish were divided into a sensitive group comprising bay

anchovy, Atlantic silverside, Atlantic menhaden, and butterfish, and a hardy group

containing a majority of the fish species tested, including winter flounder,

northern pipefish, threespine stickleback, fourspine stickleback, tautog, American

eel, hogchoker, and seaboard goby.
Initial survival (5I) observations of 18, 831 fish collected from the angled vertical traveling screens (Table 3) ranged from 1. 7% for the dominant bay anchovy to

99. 1% for hogchoker. Initial survival was 24. 3% for all taxa combined, increasing

to 89. 6% with the exclusion of bay anchovy. Extended 48-h survival observations

(SE) were made on 3855 impinged fish and resulted in an overall extended survival

va 1 ue of 77. 7%. Extended su rvi va 1 trends for the maj or taxa were 5 imi 1 ar to in itial survival and were variable among species, ranging from 1. 7% for bay anchovy to

98. 4% for tautog. For the major taxa the lowest survival (5), ~O. l%, was calculated for bay anchovy, followed by Atlantic menhaden (3. 2%), Atlantic silverside

(18. 2%), and butterfish (32. 4%). The remaining taxa had survival greater than 74%

(seaboard goby) , ranging to 96. 3% for tautog. Overall impingement survival was

18. 9%, increasing to 74. 0% with the exclusion of bay anchovy.

Total system efficiency (TSE) of the Unit 4 angled screen intake, not adjusted for

collection and handling mortality, was 32. 4% (Table 4). The diversion system

accounted for 27. 9% and the impingement system for 4. 5% of the TSE. Total system

efficiency increased to 55. 3% (47. 7% diversion plus 7. 6% impingement) with the

exclusion of bay anchovy, which constituted 41. 1% of the total estimated entrapment. TSE values for the major taxa exhibited an extremely wide range, from -:0.

for bay anchovy to 97. 9% for tautog, but generally fell into' two groups: a hardy

group with TSE values greater than 65% and a sensitive group with TSE values of

1 ess than 25%. The low reported bay anchovy survi va 1 is not un i que to Brayton

Point. Bay anchovy survival was less than 1% (ll), increasing to 12. 4% when the

collection procedure was modified to minimize collection and handling mortality

) at the Danskammer Point angled screen demonstration faci 1 ity. Eight of the 12

major species were classified as hardy: tautog (97. 9%), threespine stickleback

(96. 9%), hogchoker (96. 0%), fourspine stickleback (89. 0%), winter flounder (88. 4%),

Ameri can eel (84. 4%), northern pipefi sh (80. 2%), and seaboard goby (67. 7%). The

remaining four major species - Atlantic silverside, butterfish, Atlantic menhaden,

and bay anchovy - were classified as sensitive species, with TSE values of 23.

8, 2. 8, and ~O. l%, respectively.

The primary contributors to lower total system efficiency were low initial (SI)

survival and/or extended (5E) survival for the sensitive species. Atlantic

silverside (29. 7% of the total with 96. 9% DE), a representative of the sensitive

group with a TSE of 23. 1%, exhibited high initial survival from both impingement

(82. 1%) and diversion (81. 8%), but low extended survival, 22. 2 and 28. 4%, respectively. A substantial part of Atlantic silverside mortality was the result of the
diversion collection and handling procedures. Collection and handling mortality

estimates for both ang 1 ed screen impi ngement and the di versi on bypass coll ecti ons

were determined for the available, numerically dominant taxa (Table 5). No impingement collection and handling mortality was observed. Diversion bypass collection and handling mortality was observed to be species specific, with an overall

value for total taxa of 24. 2%, ranging from zero for tautog to 51. 6% for Atlantic

silverside. Atlantic silverside control survival (90. 8%) was 51. 6% greater than

diversion control survival (39. 2%) and slightly less than impingement control survival (92. 3%). The remaining dominant sensitive taxa (bay anchovy, Atlantic menhaden, and butterfi sh) were not tested.

CONCLUS IONS

The critical factor in assessing the effectiveness of a mitigative intake system

is the cond it i on of the fi sh diverted or returned to the source wa te r body. Co llection and handling mortality has been determined to be significant for the diversion survival program phase. At Brayton Point nets suspended in the water are used

to intercept the bypass flow , water depth at the collection site is minimal, and

turbulence in the collection net substantially increases the stress placed on the

organisms collected for survival observations. In the actual operation of an

angled screen intake system the fish would not be collected and observed, but

returned di rectly to the source water body. Thus , the true measure of system efficiency should not include mortality associated with collection and handling.

System efficiency values for the Brayton Point Station Unit 4 angled screen intake

were hi ghe r than va 1 ue s for the angl ed screen intake at Oswego Steam Stat i on Un it 6

and comparable to values for the Danskammer Point demonstration facility 

). 

The

angled screen intake system was found to be an effective device for mitigating fish

impingement and has a high diversion capability. Initial and extended survival

varied by species , but, in general, there was a " sensitive" group composed of a few

numerically dominant taxa (mostly bay anchovy and Atlantic silverside) with calculated survival below 25. 0% and a " hardy " group (mixed taxa dominated by winter

flounder and northern pipefish) with survival values greater than 65. 0%.
REFERENCES

C. H. Hanson, J. R. White, and H. W. Li. " Entrapment and Impingement of

Fishes by Power Plant Cooling-Water Intakes: An Overview. Marine Fisheries

Review , MFR Paper 1266, 39(10):7- 17. 1977.

Y. G. Mussalli, E. P. Taft, and P. Hoffman. " Biological and Engineering Considerations in the Fine Screening of Small Organisms From Cool ing Water Intakes. In Proc. Workshop on Larval Exclusion Systems for Power Plant Coolinq Water Intakes , R. K. Sharma and J. P. Palmer (eds.

). 

Argonne National

Laboratory. ANL/ES- 66. 1978.

J. B. Cannon, G. F. Cada, K. K. Campbell, D. W. Lee, and A. T. Szluha. Fish

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Civil Engineers. 1982.

5. Stone and Webster Engineering Company (SWEC). Advanced Intake Technoloqies

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American Society of

D. J. Zweiacker , J. R. Gaw, E. Green, and C. Adams. " Evaluation of an AirBubble Curtain to Reduce Impingement at an Electric Generating Station.

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Report No. 78-516-K. 1978.

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S. J. Edwards and J. B. Hutchison. " Effectiveness of a Barrier Net in Reducing White Perch (Morone americana ) and Striped Bass ( Morone saxatilis ) Im- pingement. Environ. Sci. Tech. 14(2):210-213. 1980.

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Barriers and Bubble Curtains. Fish. Res . 1(1981/1982):3- 22. 1981.

R. J. Hadderingh. " Experimental Reduction of Fish Impingement by Artificial

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10.

11. Q. J. Stober, R. W. Tyl er , and C. E. Petrosky. " Barrier Net to Reduce Entrainment Losses of Adult Kokanee From Banks Lake, Washington. North Amer

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12. V. J. Schuler. " Experimental Studies in Guiding Marine Fishes of Southern

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on Entrainment and Intake Screening , L. D. Jensen (ed.

). 

Electric Power Research Institute, Rep. 15. 1974.

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E. P. Taft, P. Hoffman, P. J. Eisele, and T. Horst. "An Experimental Approach

to the Design of Systems for Alleviating Fish Impingement at Existing and Proposed Power Plant Intake Structures. In Third National Workshop on Entrainment and Impingement , L. D. Jensen (ed.

). 

EA Communications, Melville, NY.

1976, pp. 343- 365.

14.
15. E. P. Taft and Y. G. Mussalli. " Angled Screens and Louvers for Diverting Fish

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1978.

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Laboratory Evaluation of Larval Fish Impingement and Diversion Systems.

Proc. Workshop on Advanced Intake Technoloqy , Apr. 22-24, 1981.

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El ectri c Energy Research Corporation. 1985.

17.

18. Lawler, Matusky & Skelly Engineers (LMS). Evaluation of Fish Diversion Efficiency and Survival Related to Varying Angled Screen Approach to Bypass Veloc- ity Ratios. Report Prepared for Central Hudson Gas & Electric Corporation.

1986.

19. Lawler, Matusky & Skelly Engineers (LMS). Evaluation of the Angled Screen

Fish Diversion System at Oswego Steam Station Unit 6. Research Project No.

EC 104. Apri 1 1981 - March 1983. Report prepared for Niagara Mohawk Power

Corporation. 1984.

Marine Research, Inc. (MRI), and New England Power Co. (NEP). Brayton Point

Generating Station, Mount Hope Bay, Somerset, Massachusetts. Final Environmental Impact Report and Sections 316(a) and 316(b) Demonstrations With the

Proposed Conversion of Generating Unit No. 4 From Closed-Cycle Cooling to

Once-Through Cool i ng. 1982.

20.

21. Lawler, Matusky & Skelly Engineers (LMS). Brayton Point Station Unit No.

Angled Screen Intake Biological Evaluation Program. 1984- 1986 Summary Re- port. Report prepared for New England Power Company. 1987.

22. J. A. Matousek, R. W. Davis, and S. J. Edwards. " Results of Biological Evaluation Studies Conducted at Power Plants With Angled Screen Intakes. Paper

presented at Southeastern Workshop on Aquatic Ecological Effects of Power

Generation , Sarasota, FL. 3- 5 December 1986.
Dorchester BayQuincy Bay

~Merrlmack River

Parker River

:I'

Essex Bay

,

Annisquam River

:;, ;

P;\;;

;:;:

:~"b.' 

0 16.

kmFigure 1. Location of Brayton Point Generating Station and

coastal areas of Massachusetts and Rhode Island.
LEE RIVER

INTAKE

45. 7 cmDI A.BYPASSEDSTRUCTURE

FISH RETURN

PIPES

SOUTH SCREENWEL NORTH SCREENWELL

35.6cm DIA. 30. 5cm DIA.

COOLING CANAL

(a)

LEE RIVER

INTAKE 

35. 6cm DIA. IMPINGED STRUCTURr

FISH RETURN PIPE TRA VELING

SCREENS FISH

BYPASS

COOLING CANAL

(b)

Figure 2. Brayton Point Station Unit 4 angled screen

intake structure , impinged (a) and bypassed (b) fish

return systems.
Tabl e 1

SPECIES ABUNDANCE, PERCENT COMPOSITION,

AND DIVERSION EFFICIENCY OF MAJOR TAXA AND TOTAL FISH

Brayton Point Station Unit 4

October 1984 - March 1986

Number ColI ected Collection by Location 01 version

Percent Est i mated Efficiency

Common Name Scientific Name Abundance Composition Impi ngement Diversion

(%)

Bay anchovy Anchoa mitchilli 563 41.1 13, 986 577 57.

Atlantic Menidia menidla 504 29. 727 22, 777 96.

sllverside

Wi nter flounder PseudoPl euronectes 284 10. 021 263 87.

ameri canu s

Northern pipefi sh nathus fuscus 284 548 736 52.

Threespi ne Gasterosteu s 481 1.9 113 368 92.

stickleback aculeatus

Atlantic menhaden Brevoort i a t rannus 279 1.6 124 155 90.

Fourspine Ape I tes uadracu s 108 1.4 183 925 83.

sti ckl eback

Tautog Tautoga onitis 843 1.1 319 524 62.

Ameri can eel AnQui 11 a rostrata 837 1.1 832 99.

Butterfi sh Peprilus tri acanthu s 819 1.0 782 95.

Hogchoker Trinectes maculatus 811 1.0 117 694 85.

Seaboard goby Gobiosoma ginsburgi 750 126 624 83.

Others (45 taxa) 643 485 158 86.

Total fi sh 206 18,791 60, 415 76.

Total excl udi ng 643 805 41,838 89.

bay anchovy
Tab 1 e 

DIVERSION SURVIVAL INFORMATION

Brayton Point Station Unit 4

October 1984 - March 1986

Initial Survival Extended Survival Diversion

48- SE- Survival

Number Number

Taxon Ana 1 yzed --'!L Ana 1 yzed --'!L

Bay anchovy 095 144

Atlantic si lverside 10, 338 81.8 742 28. 23.

Wi nter f1 ounder 114 96. 409 91. 88.

Northern pipefish 837 96. 799 71. 68.

Threespine stickleback 621 98. 600 98. 97.

Atlantic menhaden 606 16. 17.

Fourspi ne stickleback 448 98. 439 91. 90.

Tautog 256 99. 253 99. 98.

American eel 391 99. 85. 84.

Butterfi sh 381 49. 189 13.

Hogchoker 326 99. 322 96. 96.

Seaboard goby 294 91.2 265 72. 66.

Others (44 taxa) 479 64. 923 50. 32.

Total fi sh 28, 186 57. 209 63. 36.

Total excluding 19, 091 82. 065 64. 53.

bay anchovy
Tab 1 e 

IMPINGEMENT SURVIVAL INFORMATION

Brayton Point Station Unit 4

October 1984 - March 1986

Initial Survival Extended Survival Impi ngement

48- SE- Survival

Number Numbe r

Taxon Ana 1 vzed --ID- Ana 1 vzed --ID-

(%)

Bay anchovy 13, 987 1.7 235 (0.

Atlantic silverside 745 82. 491 22. 18.

Wi nter flounder 025 95. 787 95. 91.0

Northern pipefi sh 551 98. 134 95. 93.

Threespine stickleback 113 93. 105 96. 90.

Atlantic menhaden 126 38.

Fourspi ne stickleback 183 86. 155 96. 83.

Tautog 329 97. 317 98. 96.

American eel 60.

Butterfi sh 56. 57. 32.

Hogchoker 117 99. 115 96. 95.

Seaboard goby 126 87. 109 85. 74.

Othe rs (30 taxa) 487 70. 338 80. 56.

Tota 1 fi sh 18, 831 24. 855 77. 18.

Total excluding 844 89. 620 82. 74.

bay anchovy

..,
Table 4

SURVIVAL INFORMATION AND CALCULATED TOTAL SYSTEM EFFICIENCY

Brayton Point Station Unit 4

October 1984 - March 1986

Diversion Impi ngement Total

Di versi on Di versi on System Impi ngement Impi ngement System System

Efficiency Survival Efficiency Efficiency Survival Efficiency Effi ci ency

Taxon

(%) (%) (%) (%) (%) (%) (%)

Bay anchovy 57. 43. (0. (0. (0.

Atlantic silverside 96. 23. 22. 18. 23.

Wi nter fl ounder 87. 88. 77. 12. 91.0 11.2 88.

Northern pipefi sh 52. 68. 36. 47. 93. 43. 80.

Threespi ne st i ckl aback 92. 97. 90. 90. 96.

Atlantic menhaden 90.

Fourspine stickleback 83. 90. 75. 16. 83. 13. 89.

Taut:og 62. 98. 61.5 37. 96. 36. 97.

Ameri can eel 99. 84. 84. 84.

Butterfi sh 95. 32. 1.5

Hogchoker 85. 96. 82. 14. 95. 13. 96.

Seaboard goby 83. 66. 55. 16. 74. 12. 67.7

Others (45 taxa) 86. 32. 28. 13. 56. 35.

Total fj sh 76. 36. 27. 23. 18. 32.

Total excl udi ng 89. 53. 47. 10. 74. 55.

bay anchovy
Table 5

CONTROL TESTING SUMMARY

Brayton Point Station Unit 4

1984 - 1986

Percent

Total No. No. Live Survival

Test T Taxon Tested 48-

Divers; on Atlantic silverside 372 146 39.

Fourspine stickleback 100.

Northern pipefi sh 86.

Sea boa rd goby 73.

Tautog 100.

Winter flounder 173 151 87.

Others (5 taxa) 156 145 92.

Tota 1

838 572 68.

Impi ngement Atlantic silverside 182 168 92.

Seaboard goby 100.

Tautog 100.

Wi nter flounder 100.

Others (5 taxa) -1.Q 100.

Total 390 376 96.

Control Atlantic silverside 196 178 90.

Seaboa rd goby

95.

Tautog 100.

Winter flounder 95.

Others (5 taxa) 97.

Total 281 260 92.

--J