Post-Impingement Fish Survival 

at Dunkirk Steam Station 

Winter, Spring, Summer and Fall 

1998-1999 

Preparedfor: 

NRG Dunkrrk Power L.L.C. 

106 Point Drive North 

Dunkirk, NY14048 

Prepared by: 

Beak ConsultantsIncorporated 

140 Rotech Drive 

tancaster, NY 14086 

January 26,2000 
1.0 INTRODUCTION 

1.1 Background 

Beak Consultants fncorporated (Beak) was retained by Niagara Mohawk Power Corporation > 

LJA4 ("$to evaluate the survival of fish impinged on a newly-installf­prototype Ristroph-type sdAJ--4 

dual-flow traveling screen3at its Dunkirk Steam Station. The prototype screen was engineered by 

NMPC and manufactured by Brackett Green Incorporated. The screening system was designed PUP 53-c 

to maximize the survival of impinged fish for their return to Lake Erii, in accordance with Clean,, 2 c \I ~

I: :

Water Act Section 316(b) requirements that the intake structure reflect the best technology 

available (BTA) for minimizing adverse environmental impact. 

Impingement survival testing was conducted during four seasonal periodscwinter 1998-1999, 

Spring 1999, Summer 1999, and Fall 1999.7-The winter and spring tests were performed for 

WC. On June 6, 1999, NRG Dunkirk Power LLC assumed ownership of the station and 

proceeded with the completion of the summer and fall testing. 

Major study objectives were: 1) to estimate the post-impingement survival of commonly 

impinged species on a seasonal basis; 2) to investigate the influence of collection and handling 

on impinged fish; 3) to evaluate the effectiveness of low-pressure spray wash on the removal of 

fish fiom the screen; and 4) to determine ways to optimize post-impingement survival. 

1.2 Dunkirk Station Description 

The Dunkirk Steam Station (Dunkirk) is located on Lake Erie in the City of Dunkirk, New York. 

The station is coal-fired and has four units with a total nominal rating of 600 MW. Dunkirk - -

utilizes a once-through condenser cooling water system. Cooling system water enters the station 

through a shoreline intake located at the southwestern corner of Dunkirk Harbor. Water travels 

under a skimmer wall and enters a common forebay before passing through four sets of bar racks 

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to separate intake tunnels for Screenhouse #1 &Jn;tS 1 and 2) and Screenhouse #2 (Units 3 and I

1 

4). Water enters Screenhouse #1 to a second forebay before it passes through one of the three 

dual-flow traveling screens. 

/ 

During 1998,k of the three existing dual-flow traveling screens in Screenhouse #1 was 

replaced with an improved prototype dual-flow traveling screen. The improved traveling screen P .:i-. , in Screenhouse #1 is approximately 11 fl wide and 29 ft deep, and is made of rectangular basket 9 2’ 

/-J-/

sections connected to form an endless belt. Each basket section is covered with 1/8-inch by $4- i 

‘ inch “smooth tex” woven stainless steel cloth and has an attached bucket at the bottom to collect c““ ‘,,k? 

Y 

fish as the screens ascend (see Table 1 for details). As the screen buckets overturn at the top of 

7 )

the traveling screen, their contents are washed into a fish return trough by two inside and two +&& voutside low-pressure spray wash headers. The screen is then subjected to a high-pressure spray 

wash whch forces debris into a debris trough. The fish and debris troughs (fish trough .. 

positioned above the debris trough) empty into a common return trough, where their flow 

combines with flow carrying fish and debris fi-om Screenhouse #2 before entering a hydrostalic 

pump well. The hydrostalic pump provides the energy to deliver the fish and debris out a 15004 

fish return pipe into Lake Erie with minimal harm to the 

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3.0 RESULTS AND DISCUSSION 

3.1 Low-Pressure Spray System Efficiency Testing 

$mu?& 

Recovery ktes of marke bass and yellow percgreleased into the ascending buckets 

of the prototype screen to 1004 (Table 2). The best results (92-100%) came ,

z d-' 

with low (0-5 psi) outside spray pressures. Nearly all fish missed by the fish return trough were 

collected in the debris trough (Table 2). Detailed test results are presented in Appendix Tables 

A-2 and A-3. 

3.2 Collection and Handling Mortality Testing 

During testing on December 19,1998, none of the 49 golden shiners (handling controls) exposed 2 

to the collection table apparatus and held for 24 hours died (Table 3). One of the 71 golden 5dg'u Qshiners held for 24 hours died, which is equivalent to a 1.4% holding mortality rate or a 98.6% If., 

survival rate (Table 3). 

3.3 Post-ImpingementSurvival 

Winter Testing c

\ Thirteen species and 6,775 fish were collected for survival evaluation during eight nights of 

Lsampling on December 20-23, 1998 and January 6-9, 19991

(Table 4). Targeted species included Ji 

3,738 emerald shiners, 1,927 juvenile gizzard shad, 614 rainbow smelt, 297 spottail shiners, 93 

adult gizzard shad, 66 yellow perch, one white bass, and one freshwater drum. An additional ?­

10,911 fish were collected but not evaluated for survival. 

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-- 

-- 

,-­

__­

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Emerald shiner v fi the most abundant species collected. Fish tested ranged in length frornB5 to n 

114 mj(Appendix Table B-1). Initially, almost all (98.8%) of the 3,738 emerald shiners s5.,.”’ ~~ 

~ ~..I il -4-2 -’ collected for testing were alive and in excellent condition. After 24 hours, the total survival rate 

for emerald shiners, unadjusted for handlingholding mortality, was 98.2% (Table 4). 

JPT! 

Juvenile gizzard shad was the second most abundant species collected. Fish tested ranged in 5$,$”’’ \ 

::,: 2 - ’ length from 67 to 197 mm (Appendix Table B-2). Fifty-four of 1927juvenile shad (2.6%) were 

dead_at the time of collection, while the remaining appeared to be unstressed (Table 4). &fit4 

2 $i/-i.v’“’”d $ 

@, r, d i 3-additional. juvenile shad died and 14 appeared stress, resulting in a total impingement < id 

J 

survival . rate of 94.7%, unadjusted for handlingholding mortality.

Adult gizzard shad were not abundant, and only 92ecimens . ____. were collected. Fish tested ranged ~$,,?j 

in length from 269 to 461 mm (Appendix Table �3-3). Most of these fish were observed to have -__.___I--- A 2

lost _._____._.~_ scales along their lateral ... line, yet only three were dead at the time of collection, and one fish S?‘ 

died and three became stressed during the 24-hr holding period (Table 4). Overall, the total 

92. 5,:. -7. ic - impingement survival rate for adult gizzard shad was -----­ 92.5%, unadjusted for handlingholding zu-/’J. 

mortality. 

Rainbow smelt was the third most abundant species collected. Fish tested ranged in length from SM-.:1 

s I%+ 

r________. 56 to 147 mm, with a bi-modal distribution separating smelt into two size groups (approximating /, 

dl)d 52

juveniles and adults) at about lOOmm (Appendix Table B-4). All rainbow smelt collected, 

including both juvenile and adult fish, appeared to be unusually thin, but initial survival was n-32 2 

good (95.3%). Total impingement survival over 24 hr for all sizes combined was 83.2%, ,,),’$ /J

,­

8 > .A : ?’. ;

unadjusted for handlingholding mortality (Table 4). * Ir i:

. e.-:-

The ratio of juveniles (<lo0 mm) to adults (>lo0 mm) occurring within the measured 

subsamples of fish classified as initially dead, initially stressed, dead at 24 hr ,stressed at 24 hr, c--

I / and alive at 24 hr was used to estimate initial and extended survival of juvenile and adult 

rainbow smelt. By this method, the extended survival for juvenile and adult rainbow smelt, 

unadjusted for handlingholding mortality, was 71.0% and 88.6%, respectively (Table 5). 

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--- 

-- 

-- -- 

i 

Spottail shiner was the fourth most abundant species collected. Fish tested ranged in length &om I

sltrrw 

59 to 118 ll~m(Appendix Table 3-5)and were in excellent condition. Extended survival for cz :,* -

spottail shiner, unadjusted for handlingholding mortality, was estimated to be 99.7% (Table 4). 9~­

‘7 “&‘VI 2 -

Only 66 yellow perch were collected, ranging in length fiom 62 to 119 mm (Appendix Table B- ~~~ 

-__ 

6). ThqirGxtended survival was 100%_[Table -. 4).

Only one individual each was collected for two target species, w z b and freshwater drum-

’pa ~ 

(Table 4). Non-target species collected included rock bass, trout-perch, bluegill, shorthead -# -e-­

-

redhorse, largemouth bass and sculpin. None was abundant. 

Although a low level of holding mortality (1.4%) was observed for test fish held for 24 hr but not 

handled (Section 3.2), adjustments were not made to the extended survival rates to account for 

PkA, this control mortality. Thus, the extended survival rates could __.__I__­ be considered~ to be slightly,, 6.4.,sui 

underestimated. For some species, the observed mortality could have been explained entirely by . 

the effects of holding, and an adjustment would result in survival rates equaling or exceeding 

100%. 

Spring Testing / rCI 

/ 

- I 

A total of;3,562 fish and 2Ojspecies was collected for survival evaluation during eight nights of ,- - sampling on April 20-28, 1999 (Table 6). Targeted species included 2,564 emerald shiners, 318 1 

rainbow smelt, 260 alewife, 132 spottail shiners, 51 trout-perch, two white perch, one white bass, 

and one fieshwater drum. All fish collected, with the exception - of diseased fish, were evaluated

for survival. *5c-u-;4*L. @.JfB 

Emerald shiner was the most abundant species collected (Table 6). Fish tested ranged in length :P-P+’­

from 48 to 111 mm (Appendix Table B-7). As in the winter tests, emerald shiners were in 5 ? - ._-

excellent condition when collected, with only a 1.5% initial mortality rate (22 dead fish and 17 z,’” 

&5- 9­

stressed fish combined). Their total impingement survival rate over 24 hr was 95.0% (Table 61, 

unadjusted for handlingholding mortality. 

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-- 

-- 

-- 

- J Rainbow smelt was the second most abundant species collected (Table 6). Fish tested ranged in _,sid-f 

\.-. ~ 

length from 64 to 140 mm, with a bi-modal distribution separating smelt into two size groups --E-'< iv '62' 

L/ D "i 

(approximating juveniles and adults) at about 100 mm (Appendix Table B-8). However, smelt (~f~..~': 5 " ? 

were not separated into size groups for analysis due to the small sample size. As in the winter 

tests, all fainbow smelt collected, including both juvenile and adult fish, appeared to be unusually 

thin, but initial survival was good (89.3%). However, some additional mortality was recorded 

during the 24-hr holding period, resulting in a total impingement survival of 63.2% (Table 6) for 

all sizes combined, unadjusted for handlingholding mortality. 

A total of 260 alewives - was collected, making this the third most abundant species (Table 6). r -

Fish tested ranged in length from 89 to 210 m (Appendix Table B-9). Although their initial 

survival was good (83.5%), 129 fish died during the 24-hr holding period and 10 fish became 

stressed, lowering the total survival for alewife to 30.0% (Table 6), unadjusted for handling and 

holding mortality. 

Although not a target species for the spring, juvenile gizzard shad .. .~ was the fourth most abundant

species collected. Fish tested ranged in length from___~ 92 to 183 mm (Appendix Table B-10). 

Overall, the total impingement survival for juvenile gizzard shad, unadjusted �or 

handlingholding mortality, was 64.9% (Table 6). 

Spottail shiner was the fifth most abundant species collected. Spottail shiners ranged in length 

&om 45 to 125--1nm(Appendix Table B-1 1) and were in excellent condition. Total survival for -__­

spottail shiner over 24 hr, unadjusted for handlingholding mortality, was estimated to be 98.5% -

(Table 6). 

Trout-perch was the sixth most abundant species collected. Fish tested ranged in length from/66 /---

to 129 rnm (Appendix Table B-12). The total survival rate for trout-perch, unadjusted for . ­

handlingholding mortality, was estimated to be 94.1% (Table 6). 

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;-' -9 . -f

Additional target species collected included two white perch, and one each of white bass and , : 

i

freshwater drurn. All survived (Table 6). 

Non-target species collected included rock bass, rainbow trout, sculpin, round goby, johnny -

darter, quillback sucker, yellow perch, black crappie, fathead minnow, bluntnose minnow and 

bluegill (Table 6). None was abundant. With the exception of quillback sucker, all test fish for 

the non-target species survived (Table 6). 

1% 

Although a low level of holding mortality (1.4%) was observed for test fish held for 24 hr but not 

handled during the falvwinter at DuIlkirk Station (Section 3.2), no adjustments were made to the 

extended survival rates to account for this control mortality. Thus,the extended survixa�-rates Dfi--! 

3,L"'aJ 

__---

could be_...._.__..__~.___..._..-_.._.I considered to be slightly .....-.- underestimated. - .~ ..... 

_./--­.. , Summer Testing ' 

__---

Seventeen species and 1,220 fish (Table 7) were collected for survival evaluation during eight 

nights of sampling in late August and early September (August 16-20 and August 30-September 

3). The lower number of fish tested in the summer than in other seasons was a reflection of 

reduced impingement rates during summer months at Dunkirk. Due to the low impingement 

rates, the desired minimum number of test specimens (200) was not available for testing the three 

target species. In all, 48 rainbow smelt, 12 alewives, and six white bass were collected and 

tested (Table 7). 

All rainbow smelt were of the size equivalent to young-of-the-year and were less than 69 mm 

long (Appendix Table B-13). Although their initial survival rate was good (79.2%), the total 24­

hr survival rate for rainbow smelt in the smer testing, unadjusted for handlingholding 

mortality, was only 18.8% (Table 7). This survival rate was considerably lower than the winter 

rate of 70.5% for smelt less than 100 mm (Table 5) or the spring rate of 63.2% (Table 6), when 

they were 70 to 148 mm long. The lower survival rate in the summer may have been due to the 

warmer water temperatures (21-26 "C)than in the winter (0-12 "C) or spring (7-16 "C), or to the 

smaller size and more fragile condition of the young-of-the-year fish inthe summer. 

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9 
All but one of the alewives also appeared to be young-of-the-year and were 40 to 81 mm long; 

the one exception was 162 mm long (Appendix Table B-14). Only 25% of the alewives 

collected were alive initially and none survived for 24 hr (Table 7). The summer survival rate 

(0%) for these young-of-the-year alewives was lower than the spring rate of 30% for yearling and *+ 

older alewives 95 to 219 mm long (Table 6). Like the rainbow smelt, the lower survival rate in 

the summer may have been due to the warmer water temperatures (21-26 "C) than in the spring 

(7-16 "C),or to the smaller size and more fragile condition of the young-of-the-year fish in the 

summer. 

White bass were never abundant in the impingement collections at Dunkirk during the 1998­

1999 testing. In August-September tests, all but one of the six white bass survived during the 24­

hr holding period, yielding a total survival rate of 83.3% (Table 7), unadjusted for handling and 

holding mortality. In the two previous seasonal tests, two white bass were caught and tested, and 

both survived, suggesting that impingement survival should be high for white bass in all seasons. 

The three most abundant species collected in August-September were spottail shiner (393 fish), 

gizzard shad (338 fish), and rock bass (300 fish). Spottail shiner and gizzard shad had been 

target species for seasonal testing in the winter and spring. The extended survival rate was 

90.8% for spottail shiner, 70.7% for gizzard shad, and 99.3% for rock bass (Table 7). These 

summer rates for the three species were similar to the rates recorded in winter and spring testing 

(Tables 4 and 6), yet these species, like almost all of the species collected in the summer, were 

represented by young-of-the-year fish. 

Fall Testing 

Twenty-seven species and 8928 fish (Table 8) were collected for survival evaluation during eight 

nights of sampling (November 2-11). Of the four seasons of testing, fall collections provided the 

greatest number of fish and species. Targeted species collected included 6,072 emerald shiners, 

�,488juvenile gizzard shad, 473 rainbow smelt, 263 spottail shiners, 178 yellow perch, 147 

white bass, 45 white perch, and one adult gizzard shad. No alewives were collected. 

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Emerald shiner was the most abundant species collected, as in the winter and spring testing, 

when 24-hr survival rates were 98.2% and 95.0%, respectively (Tables 4 and 6). The total 

survival rate over 24 hr for emerald shiners in the fall, unadjusted for handlingholding mortality, 

was 98.0%(Table 8). Tested fish ranged in length fiom 27 mm to 95 mm (Appendix Table B16) and were in excellent condition. 

Gizzard shad was the second most abundant species in the impingement collections, and 

consisted ofjuveniles (Appendix Table B-17) and 12 adults (Appendix Table B-'18). All but five 

of the 1477juveniles collected were alive, equivalent to a 99.7% initial survival rate, while 11 of 

the 12 adults (91.7%) were alive initially (Table 8). Adult gizzard shad typically had lost scales 

along their lateral line, as observed in earlier tests. Despite this scale loss, the unadjusted total 

survival rate for adult gizzard shad over 24 hr was 91.7% (Table 8). The unadjusted 24-hr total 

survival rate for juvenile gizzard shad in the fall was 98.6%, similar to the 94.7% survival rate 

observed during testing in December and Jan=, but higher than the rates in April (64.9%) and 

August-September (70.7%). 

Rainbow smelt, the third most abundant species collected in November, had a 75.9% unadjusted 

total survival rate over 24 hr (Table 8), which was similar to the 83.2% rate in December-January 

(Tables 4 and 5) and slightly higher than the 63.2% rate in April (Table 6). The lower rate 

(18.8%) recorded in August-September likely was associated with the small size (42 to 68 mm) 

and early age of the impinged rainbow smelt or the higher water temperatures then, as discussed LF/ 

above. Smelt collected in November ranged in length from 79 mm to 175 mm (Appendix Table 

B-19). 

Although never as abundant as the emerald shiner, the spottail shiner has shown high 

impingement survival like its congener, ranging &om 90.8% in August-September to 98.5% 

during the fall testing in November (Table 8). Spottail shiners in November ranged in length 

from 26 mm to 109 mm (Appendix Table B-20). 

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More yellow perch (178 fish; Table 8) were collected in the fall sampling than in DecemberJanuary (66 fish), April (0 fish) and August-September (14 fish) sampling. There was a 

relatively wide range of sizes of yellow perch collected in November, li-om 55 mm to 212 mm 

total length (Appendix Table B-21). Yellow perch had a 98.9% total impingement survival rate 

over 24 hr in November (Table 8), compared to 100Y0in December-January and 92.9% in 

August-September. 

Like yellow perch, more white bass were collected in fall sampling (147 fish) than in DecemberJanuary (one fish), April (one fish) and August-September (six fish) sampling. Thus, November 

testing provided the first opportunity to get a reliable estimate of 24-hr survival for this species. 

The total survivalrate inNovember was 98.6% (Table 8). 

White perch, a target species in all seasons except summer, has been relatively uncommon in 

collections, with only 45 appearing in November, none in December-January, two in April, and 

22 in August-September. All white perch collected have survived,' indicating a 100% survival 

rate for the three seasons in which they were collected (Tables 4,7 and 8). 

Impingement survival was high for all Don-target species in November (Table 8), although 

sample sizes were small (25 fish or fewer) for all but rock bass (157 fish). Only three species 

had a survival rate less than 100%. Bluntnose minnow and smallmouth bass each had one of six 

fish die, an 83% survival rate. The sole freshwater drum collected in November was stressed, 

and thus was treated as a mortality (Table 8). 

Water Quality Monitoring and Station Operating Conditions 

Intake water temperatures ranged &om 5 to 12 "C during the fKst four days of winter testing, 

December 20-23 (Appendix Table C-1). Temperatures during the remaining four days of testing, 

January 6-9, ranged fiom 0 to 4 "C (Appendix Table (2-1). DO concentrations were at, or near, 

saturation at all times. With the exception of the first day, all circulating and service water 

pumps remained on line during the study (Appendix Table C-1). Water quality in the extended 

survival holding tanks was generally the same as at the intake during the first four days of testing 

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{Appendix Tables C-1 and C-2). During the last four days of testing, water temperature in the 

extended survival holding tanks was 6 to 10 OC warmer than in the intake due to the station's 

recirculation system (Appendix Tables C-1 and C-2). Recirculated water enters at the head of 

the Unit 1 and Unit 2 forebay, so it can be presumed that impinged fish were exposed to the 

recirculated water for some time prior to being impinged. 

During April 20-28 testing, intake water temperatures ranged from 7.5 to 13 "C (Appendix Table 

C-3). DO concentrations were at, or near, saturation at all times. All circulating and service 

water pumps remained on line during the study (Appendix Table C-3). Water quality in the 

extended survival holding tanks was generally the same as at the intake (Appendix Tables C-3 

and C-4). 

During August 16-20 and August 30-September 3 testing, intake water temperatures ranged from 

19 to 25 "C (Appendix Table C-5). During November 2-11 testing, intake water temperatures 

ranged fi-om 9.0 "C to 13.0 "C (Appendix Table C-7). For both surnmer and fall testing, DO 

concentrations were at, or near, saturation at all times. All circulating and service water pumps 

remained on line during the study (Appendix Tables C-5 and C-7). Water temperatures in the 

extended survival holding tanks were within 1-2 "C of the temperatures recorded in the intake, 

and the DO concentrations were at or near saturation (Appendix Tables C-5 and C-6, and Tables 

C-7 ad C-8). 

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4.0 OPTIMIZATION 

The prototype traveling screen installed at Dunkirk has incorporated into its design many fish 

mortality minimizing features. These features include: 1) smooth woven wire screen; 2) 

"Ristr~ph"6sh buckets with a modified bucket lip to reduce turbulence in the bucket; and 3) 

separate low-pressure fish spray wash and high-pressure debris spray wash systems. 

Additionally, the prototype screen has a nose cone and a set of fairings to more uniformly 

disfribute flow across the screen face. 

The design features of the fish removal and return system appear to be hctioniag well. 

Impinged fish generally were in very good to excellent condition, indicating that the combination 

of smooth woven wire screens, screen rotation speeds, and spray wash pressures was effective in 

reducing damage to the fish. The only signs of injury &e., de-scaling) were observed with 

gizzard shad, which are characterized by Scott and Crossman (1973) as having scales that are 

easily shed (deciduous). The fish trough width and water depth were sufficient to prevent 

damaging fish during transport to the return system. 

Improvements to collection efficiency have the effect of improving fish survival. This assumes 

fish not captured by the fish return system are sent through the cooling system and experience 

mortality. It also assumes fish directed into the debris trough experience higher mortality than 

those directed into the fish return trough. Collection efficiency results indicate few fish are 

missed by the screens and sent through the plant. 

Potential actions to improve collection efficiency at Dunkirk include the following: 

0 Operate the outside spray wash pressure at 5 psi. 

The gap between the flap seal and the descending screen should be minimized. We did not 

measure this gap, but the flap seal did not appear to come into close contact with the screen, 

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We recommend that the flap seal be adjusted and re-tested. Since collection efficiency is 

already high, only small improvements are necessary. 

* The lower outside spray nozzles are presently being directed nearly straight down, slightly 

towards the screen. This may be forcing fish into the gap between the flap seal and the 

2 

screen. This row of nozzles should be not used or should be re-directed. 

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5.0 DISCUSSION 

Fish species selected as target species were typically the most frequently impinged species 

seasonally at Dunkirk. By emphasizing the post-impingement survival of these target species, 

the survival of the majority of impinged fish can be evaluated. The target species selected .?. 

historically have demonstrated a relatively wide variation in impingement survival rates at 

Dunkirk and other steam generating facilities where tests have been conducted. 

’ Beaudrey dual-flow screens were installed in both screenhouses at Dunkirk during 1985-1986 

(Beak 1988). A 12-month program was conducted in 1987 to evaluate the survival of fish 

impinged on these newly-installed screens to determine the feasibility of retrofitting a fish return 

system as a mitigation for impingement losses. A follow-up study was conducted between 

August 1990 and January 1991 to determine the effects of continuous vs. intermittent screen 

operation on fish survival (Lindsay 1991). 

The survival results &om these two earlier studies were compared to the results of the present 

(1998-1999) study to determine whether the screen system modifications described in Section 

4.0 (smooth woven wire screen, “Ri~tr~ph”fish buckets with a modified bucket lip to reduce 

turbulence in the bucket, separate low-pressure fish spray wash and high-pressure debris spray 

wash systems, and nose cone and fairings to more uniformly distribute flow across the screen 

face) substantially improved the post-impingement survival of fish. The effects of system 

modifications should be most evident for species previously experiencing comparatively lower 

survival rates. These “fragile” species typically include clupeids, such as alewife and gizzard 

shad, and rainbow smelt. 

Precautions must be taken in interpreting the results of the survival test comparison. The earlier. 

tests were conducted in Screenhouse #2, rather than Screenhouse #1, the site of the present study. 

Differences in flow characteristics between the two screenhouses could influence the survival 

results. Also, fish handling procedures differed between the studies. Fish collected during the 

1987 study were removed from a collection table by using dipnets, which may have stressed the 

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fish more than the brailing procedures used in the present study. The use of dipnets in the 1987 

tests may have artificially increased fish mortality estimates in 1987 compared to the 1999 

estimates. On the other hand, impingement mortality estimates for 1998-1999 are biased high 

(conservative) because stressed fish were counted as dead fish, whereas stressed fish were 

counted live fish in the 1987 study. Nevertheless, substantial differences in the estimated 

survival r'ates between the present and past study years may reflect the effects of the system 

modifications made to the new prototype screen. 

Table 9 presents a survival rate comparison for seven target species for which there are seasonal 

data available. Since the data from the 1990-1991 study pertain to six months of testing (AugustJ~nuary)and the data were not broken down by months, the results were arbifxaily applied to the 

fall season in the table. Only the results from testing during continuous screen operation in 

1990-1991 are utilized. Where more than one test or life stage were reported Within a season, a 

range of survival values and sample sizes are presented in the table. The following months were 

assigned seasonally to group the test results for the 1987. and 1998-1999 studies: winter 

(December-March), spring (April-June), summer (July-September), and fall (OctoberNovember). 

Overall, the survival rates for seven target species appeared to be improved during the present 

study in comparison to the earlier studies (Table 9). The greatest improvement in survival 

occurred for alewife, juvenile gizzard shad, rainbow smelt and white perch. Alewife survival 

prior to the 1998-1999 modifications was 40% during the fall months (Table 9). Alewife 

survival in the spring in 1999, when sample size was relatively large (260 fish), was 30%(Table 

9). Differences in seasonal conditions and fish sizehge could influence the results of the two 

years, but a 30% survival is unusually high for this species (McLaren and Tuttle 1999). Between 

the earlier and present studies, juvenile gizzard shad survival at Dunkirk increased from 27% to 

95% in the winter, 9% to 71% in the summer, and 16-78% to 99% in the fall (Table 9). Rainbow 

smelt survival increased from 23-59% to 76% in the fall, but was less affected in the winter (59­

91% to 83%) and spring (54% to 63%)- White perch survival was 100% during the 1998-1999 

testing, but only 56-57% in the 1987 tests (Table 9). There were improvements in survival even 

NRG Dunkirk Power LLC 21 Beak Consultants Incorporated 

January 26,2000 File:dunlrik-4season-final.doc 
for species exhibiting high survival rates in the early studies, such as emerald shiner (67438% 

earlier to 98% now), white bass (5148% earlier to 83-99% now), and yellow perch (81-94% 

earlier to 93-100% now). 

In summary,' the spray wash and collection system appear to efficiently remove impinged fish 

from the traveling screen to the fish return trough. The survival tests conducted during this study 

indicate that the fish should be in good condition for return to Lake Erie, as reflected by their 

condition within the fish retum trough. Modifications made to the traveling screens, screenwells 

and spray wash system, as demonstrated by the prototype tested in Screenhouse #1, appeared to 

increase the 24-hr, post-impingement survival rate of several fish species commonly impinged at 

Dunkirk, particularly the most fragile species: alewife, rainbow smelt and gizzard shad. For 

many species, the 24-hr impingement survival rates have approached or equaled 100%- In 

addition, no adjustments have been made to account for holding and handling mortality. Thus, 

for many species having a survival rate less than ZOO%, the observed mortality may have been 

due largely or solely to the effects of handling and holding. Survival rates also may be 

underestimated because stressed fish were considered to be dead. For these reasons, further 

refinements in screening system design may not produce tangible increases in survival. 

NRG Dunkirk Power LLC 22 Beak Consultants Incorporated 

January 26,2000 File:dunkirk-4season_final.doc 
Table 1. Physical characteristics of the prototype dual-flow traveling screen 

at the Dunkirk Steam Station. 

GeneraVSite Data 

number of traveling screens 

manufacturer 

1operating deck level I 

design high water level 

design low water level 

channel base level 

lscreenwell width ~ 1 

lchannel deoth f 

number of screen speeds 

low screen speed 

high screen speed 

Hydraulic Data 

Screen Data 

[effective screen width I 

hmber of basket sections I 

F===l Brackett Green 

1 581.5 I 

1 If' 2" I 

I 29' I I variable 1 

12' I min 

64' / min I 

2.84" I 

1 <1'/sec I 

I 6' 0" I 

6' 0'' I 

1 two I 

f tW0 

I 162-230 gpm f 

I 

I 

Low Press 

1 

I 

number of inside spray headers 

number of outside spray headers 

number of spray nozzles per spray header 

inside spray pressure 

outside spray pressure 

f 
Table 1. Continued. 

High Pressure Debris Spray System Data 

number of inside spray headers 

number of mrav nozzles Der mrav header 

I inside surav uressure I 

[highpressure water required I 

;Fish Return System Data 

volume of water supplied to fish trough 

murox. vol. of water sumliedto fish return 

method of fish transport 

diameter of fish return pipe 

approximate length of fish return 

approximate velocity 

two 

7/6 

1 hydrostaltic pump 1 
4 

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Table 2. Summaryof collection efficiency results on December 2,1998 

at the Dunkirk Station. 

Inside Outside Number Number Number Percent Percent 

Spray Spray Released Recovered Recovered Recovered Recovered 

Pressure, Pressure from Fish from Debris from Fish from Fish dk 

(Psi) (Psi) Trough Trough Trough Debris Trough 
42 

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