## Post-Impingement Fish Survival atDunkirk Steam Station Winter, Spring,Summer and Fall 

## 1998-1999

Prepared for: 

### NRGDunkrrkPower

### L.L.C. 106PointDriveNorth Dunkirk,

### NY 14048 Prepared by: Beak ConsultantsIncorporated 140RotechDrive tancaster,

### NY 14086 January 26,20001.0 

### 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-install

# f­ prototype Ristroph-type sdAJ--4 dual-flow traveling screen 

# 3

at its Dunkirk SteamStation. 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 

### ofimpinged fish for their return to Lake 

### Erii, in accordancewith Clean,, 2 c \ I ~ 

# I: : Water Act Section 316(b) requirements that the intake structure reflect the best technology available

### (BTA) forminimizing adverseenvironmentalimpact. 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 ofthe summerand falltesting. 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; and4) to determine

### ways to optimizepost-impingement survival.

1.2 Dunkirk StationDescription
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 condensercooling water system. Cooling system water enters the station through a shoreline intake located at the southwesterncorner of Dunkirk Harbor. Water travels under a skimmer wall and enters a common forebaybeforepassing through four sets ofbar racks hXG Dunlcirk Power LLC 1 Beak ConsultantsIncorporated January26,2000 File:dunkirk4season-final.docto separate intake tunnels for Screenhouse#1 &Jn;tS 

### 1and 

### 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 

### ofrectangular basket 

## 9 2’

/-J-/ sections connected to form an endless belt. Each basket section is covered with 1/8-inchby $4- i ‘ inch “smooth tex” woven stainless steel cloth 

### and has an attachedbucket at the bottom to collect 

### c““ ‘,,k? Y fish as the screens ascend (see Table 

### 1 for details). 

### As the screenbuckets 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-omScreenhouse #2 before entering a hydrostalic pump well. The hydrostalicpump provides the energyto deliverthe fish and debris out a 15004 fish return pipe into Lake Erie with minimal harm to the

NRG DunkirkPowerLLC 2 Beak ConsuitantsIncorporated January 24,2000 File:dunkirk-4season-hal.doc3.0 

### RESULTS AND 

### DISCUSSION

3.1 Low-Pressure Spray

### SystemEfficiencyTesting $mu?& Recoveryktes ofmarke 

### bass and yellow percgreleased into the ascendingbuckets of the prototype screen to 1004(Table 2). The best results (92-100%) came 

## , z d-' with low 

### (0-5 psi) outside spraypressures. 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 HandlingMortalityTesting During testing 

### on December 19,1998,none of the 49 golden shiners (handlingcontrols) exposed 

## 2 to the collection table apparatus and held 

### for 24 

### hours died (Table 3). One of the 

### 71 golden 5dg'uQshiners held for 

### 24 

### hours died, which 

### is equivalentto a 

### 1.4% holding mortality rate 

### or a 

### 98.6% 

### If., survivalrate (Table 3).

3.3 Post-ImpingementSurvival
Winter 

### Testing

c 

## \ Thirteen species and 

### 6,775 fish were collected for survival evaluation 

### during eight nights 

### of 

### L

sampling on December 20-23, 1998 and 

### January 6-9, 1999 1

(Table 4). Targeted species included Ji 3,738 emerald shiners, 1,927juvenile 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 fishwere collectedbut not evaluated for survival.

NRG Dunkirk PowerLLC 9 Beak ConsultantsIncorporated January26,2000 File:

### dunkirk4season.�ir~al-doc--

-- 

## __­ ,-­ s,-p Emerald shiner v fi the most abundant species collected. Fish testedranged in length 

### frornB5to

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

### s5.,.”’

~~

il
~ ~..I -4-2 -’ collected for testing were alive and in excellent condition. After 24 hours, the total survival rate foremerald shiners, unadjusted for handlingholding mortality, was 98.2% (Table4). JP T! 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 survivalrate of94.7%,unadjusted forhandlingholding 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 ofthese fish were observed to have A 2 

### -__.___I-- -

_._____._.~_ ... lost scalesalong their lateral line, yet onlythree 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 distributionseparating smelt into 

### two size groups (approximating 

### /, 52 dl)d 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 (Table4). * 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 forjuvenile and adult rainbow smelt, unadjusted forhandlingholding mortality, was 71.0% and 88.6%,respectively (Table 5). NRG DunkirkPower LLC 10 Beak ConsultantsIncorporated January 26,2000 File:dunkirk-4seasonl.doc---

--

-- --



### i I Spottailshinerwas the fourth most abundant species collected. Fish tested ranged in length &om 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 estimatedto 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 survivalwas 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, largemouthbass and sculpin. None was abundant. Although a low level ofholding 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,

__.__I__­ this control mortality. Thus, the extended survival rates could 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 evaluationduring 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 whiteperch, 

### one white bass, and one fieshwaterdrum. All fish collected, with the exception of diseased fish, were evaluated 

## - for survival. 

### *5 c-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 survivalrate over 24 hr was 95.0% (Table 

### 61, unadjusted forhandlingholding mortality. NRG DunkirkPower LLC 11 Beak ConsultantsIncorporated January 26,2000 File:dunlcjrk-4season_final.doc-- 

# --

-- - 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 (approximatingjuveniles 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, allfainbowsmeltcollected, includingbothjuvenile and adult fish, appeared to be unusually thin, but initial survival was good (89.3%). However, some additional mortality was recorded duringthe 24-hr holding period, resulting in a total impingement survival of 63.2% (Table 6) for all sizescombined,unadjusted forhandlingholding 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 holdingmortality. 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 &om45 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).

NRG Dunkirk Power LLC 12 Beak Consuitants Incorporated January 26,2000 File:dunhirk-4season-finaLdoc;-' -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 

### ofholding mortality 

### (1.4%) was observed 

### for test 

### fishheld 

### for 24

### hrbut 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 

## __--- consideredto be slightlyunderestimated. could be _...._.__..__~.___..._..-_.._.I .....-.- - .~ .. . ..

_.

/--­ 

### ..
,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 desiredminimum number oftest specimens(200) 

### was not availablefor 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%), 

### thetotal 24­ hr survival rate for rainbow smelt in the smertesting, 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 fragilecondition ofthe young-of-the-year fish inthe summer. NRG Dunkirk Power LLC 13 BeakConsultants Incorporated January 26,2000 File:dunkirk-4season-final.doc 

# 9All 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%) fortheseyoung-of-the-year alewiveswas lower than the springrate of 30% for yearling and *+ older alewives 95 to 219 

### mm long (Table 6). Like the rainbow smelt, the lower survivalrate in the summermay 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 1999testing. 

### In August-Septembertests, all but one ofthe 

### six whitebass survived during the 24­ hr holding period, yielding a total survival rate of 83.3% (Table 7), unadjusted for handling and holdingmortality. 

### Inthe two previous seasonaltests, two whitebass were caught 

### andtested, and both survived, suggestingthat impingement survivalshouldbe 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
summerrates 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 representedby young-of-the-year fish.
Fall Testing Twenty-seven species and 8928 fish (Table 8) were collected for survival evaluationduring eight nights of sampling (November 2-1 1). Ofthe four seasonsoftesting, fall collectionsprovided the greatest number 

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

### �,488 juvenile gizzard shad, 473 rainbow smelt, 263 spottail shiners, 178 yellow perch, 147 white bass, 45 whiteperch, and one adult gizzard shad. 

### No alewiveswere collected. NRG Dunkirk PowerLLC 14 Beak ConsultantsIncorporated January 26,2000 File:dunk&k-&eason_final.docEmerald 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 survivalrate over 24 

### hr for emerald shinersinthe 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 consistedofjuveniles (Appendix TableB-17) and 12adults (Appendix TableB-'18). All but five ofthe 1477juveniles collected were alive, equivalentto a 99.7% initial survivalrate, 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 forjuvenile 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 survivalrate over24hr (Table 8), which

### was similar to the 83.2% rate inDecember-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 temperaturesthen, 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 from26 

### mm to 109mm (AppendixTableB-20).

NRG DunkirkPower LLC 15 

### >a January26,2000 File:dudcirk-4season-finaLdoc 

## 5

# I I 

# I 

# I I 

# 1 I i 

# t I 

# 1 1 1 

# I I I I 

# I 

# I 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 seasonsin which they were collected(Tables4,7 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 smallmouthbass 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

### QualityMonitoring

### andStation Operating 

### Conditions Intake water temperatures ranged &om 5 to 12 

### "C during the fKst four days of winter testing, December20-23 (Appendix Table 

### C- 1). Temperatures during the remaining four days oftesting, 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 survivalholding tanks was generallythe same as at the intake duringthe first fourdays oftesting NRG Dunkirk PowerLLC 16 Beak ComultantsIncorporated January 26,2000 File:dunkirE;--4season_final.doc{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 

### sometimeprior tobeing 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 16-20and August 30-September 3testing, intakewater temperaturesranged 

### from 19 to 25 

### "C (Appendix Table 

### C-5). During November 2-1 

### 1testing, 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 concentrationswere at 

### or near saturation (Appendix Tables 

### C-5 and C-6, and Tables 

### C-7 ad 

### C-8).

NRG DunkirkPowerLLC 17 Beak Consultants Incorporated January 26,2000 File:dunkirk-4season_finaLdoc4.0 

### 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 disfributeflow acrossthe 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 smoothwoven wire screens, screenrotation 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 damagingfish duringtransportto thereturn 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 screensand sent through the plant.
Potential actions to improve collectionefficiency at

### Dunkirkinclude the following:

0 Operatethe outside spraywash pressure at 

### 5psi.
The gap between the flap seal and the descending screen should be minimized. We did not measure this gap, but the flap seal didnot appear to come into close contact with the screen,

NRG DunkirkPower LLC 18 Beak Consultants Incorporated January 26,2000 File:dunkirk4season-hd.docWe recommend that the flap seal be adjusted and re-tested. Since collection efficiency is already

### high, only small improvements arenecessary. 

### * 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 ofnozzles shouldbe not used or shouldbe re-directed.

NRG DunkirkPowerLLC 19 

# 1 January 26,2000 File:dunkirk-4season-fhaLdoc5.0 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 

### Dunkirkand other steamgeneratingfacilitieswhere testshave 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 1991to 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 interpretingthe results of the survivaltest comparison. The earlier. tests were conductedin Screenhouse

### #2, rather than Screenhouse#1, the siteofthe 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 1987study were removed from acollectiontable by using dipnets, which may have stressed the NRG DunlrirkPower LLC 20 Beak ConsultantsIncorporated January 26,2000 File:dunkirk-4season-hal.docfish more than the brailing procedures used 

### inthe 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 modificationsmade 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 1990-1991studypertain to six months oftesting (AugustJ~nuary) and the data were not broken downby 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 survivalvalues and sample sizes arepresented 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 survivalin 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 survivalincreased from23-59% to 76% inthe 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 1987tests (Table 9). There were improvements in survival even NRG Dunkirk PowerLLC 21 Beak ConsultantsIncorporated January 26,2000 File:dunlrik-4season-final.docfor 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% earlierto 93-100% now).


### In summary,' the spray wash and collection system appear to efficiently remove impinged fish fromthe traveling screen to the fish return trough. The survivaltests conductedduringthis study indicate that the fish should be in good condition for return to 

### Lake Erie, as reflected by their conditionwithin the fish retum trough. Modifications made to the traveling screens, screenwells and spray wash system, as demonstratedby the prototype tested in Screenhouse

### #1, appeared to increasethe 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 tangibleincreases 

### in survival.

NRG Dunkirk PowerLLC 22 Beak ConsultantsIncorporated January 26,2000 File:dunkirk-4season_final.docTable 1. Physical characteristics

### ofthe prototype dual-flow travelingscreen at the Dunkirk Steam 

### Station. GeneraVSiteData number 

### oftraveling screens manufacturer 

## 1operatingdeck level 

## I designhigh water level design low water level channelbase level lscreenwellwidth

~ 

## 1 lchanneldeoth 

## f number 

### of screen speeds low screen speed high screen speed Hydraulic Data

Screen Data [effectivescreenwidth 

# I hmberofbasket sections 

## I 

# F===l Brackett Green 

# 1 581.5 

# I

1 If'2" 

## I 

# I 29' 

# I I variable 

# 1 12' Imin 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 

### ofinside sprayheaders number 

### ofoutside sprayheaders number 

### ofspray nozzlesper sprayheader inside spraypressure outside spraypressure 

# f

### Table 1. Continued. High PressureDebris SpraySystemData number ofinside spray headers number ofmrav nozzles Der mrav header 

## Iinside suravuressure 

## I [highpressure water required 

# I ;Fish Return 

### SystemData volume 

### ofwater suppliedto fish 

### trough murox. vol. 

### ofwater 

### sumliedto fish return method 

### offish transport diameteroffish return pipe approximate length offishreturn approximate velocity 

### two 

### 7/6



# 1 hydrostalticpump 

# 1

# 4 J 

# I I t 

# t 

# i 

# 1 

# 1 

# I I 

# 1 I t I I I Table 2. Summaryofcollectionefficiencyresults onDecember2,1998 at the Dunkirk Station.
Inside Outside Number Number Number Percent Percent Spray Spray Released Recovered Recovered Recovered Recovered Pressure, Pressure fromFish from Debris from Fish fromFishdk (Psi) (Psi) Trough Trough Trough Debris Trough42 m 

# * * o

oo

U a Q) U



### -

Y m Y* 

### 2 00 0 rcl 0 0 0 0.0 0 0 0 0

00000000000000

ul c x

# - 3 0 P E .-.I a & 

# - Y CI 1 a a * 

# - a E a

# lil 1 

# i 1 

# i 

# I I 1 

# I 

# I I I 

# I I I 1I



# I t 

# 1 I 

# Iw I 

## 8 g
m

10 N VI UJ 2

,.­ 00 9 ‘c! c? 

## 5 m UJ 00

m P- O m ru m

04 ”: -I-- I-- UJ N &< 09 m 00 cn d

P Q