### ABSTRACT Fish impingement data were collected at four generating facilities representing river intake, epilimnetic reservoir intake, and hypolimnetic reservoir (skimmer-wall) intake designs. The study sites included 

### both traveliig and stationary intake-screen systems. At all sites fewer species

were represented in impingement samples than were collected during concurrent field investigations in the study

areas. Significant differences in impingement rates among
seasons were established andwere caused primarily by large numbers of threadfin shad impinged during the coldest months. Intake velocities did not determinerelative rates of impingement at the sites studied. Certain characteristics 

### of intake design appeared to influence impingement rates significantly, however. Skimmer walls, present attwo sites, 

### did not provide a deterrent to

### fuh impingement.

'A continuous supply

### of condenser coolingwater

### isrequired in the operation of steam electric stations using oncethrough coding systems. Losses due to impingement represent a potentially significant impact on existing fisheries, depending on the number 

### offishinvolved andthe species affected. The impingement 

### of 

### fuh on the intake

screens of power stations presents problems in terms 

### of operatingefficiency as well as from a biological standpoint (Edsall and Yocom, 

### 1972). Losses due to impingement do not necessarily represent significant losses to resident fish populations, however (Landry and Strawn, 

### 1974). Our study, initiated 

### in the spring 

### of 

### 1974,was designed 

### to monitor impingement rates. Data were analyzed in 

### an effort to explain some of the causative factors involved in the impingement of fish and to provide an indication 

### of overall effects on resident fBheries. Fish-impingement data
were collected at four generating facilities operated by Duke Power Company. The sites include an epilimnetic reservoir intake design (Men Steam Station), two hypelimnetic reservoir (skimmer-wall) intake designs (Marshal1 Steam Station and Oconee Nuclear Station), and a river intake design (Buck Steam Station). Condenser cooling at each of these sites is accomplished 

### with a once-through open-loopsystem.


### DESCRIPTION 

### OF 

### STUDYAREAS Allen Steam Station Allen Steam Station, an epilimnetic reservoir intake design located in Gaston County, N. C., draws condensercooling water from the northern end 

### of Lake Wylie, a 5040-ha impoundment. This five-unit coal-burning facility began operating in 

### 1957 and has a total capacity of 

### 1140Mw(e). The intake structure, comprised 

### of 

### 10pumps 

### with a maximum total flow

### of 35m3/sec, is located at the back of a small cove 

### of -1.5 ha. Intake velocities are indicated

### in Table 

### 1. An extensive study of the Lake Wylie fishery was conducted from September 

### 1973 to August 

### 1974 (Industrial Bio-Test Laboratories, Inc., 

### 1974). A 

### total 

### of 

### 40 species 

### of fishes representing 

### 10 families were collected 

### with gd nets and electrofishing gear. Collections were comprised primarily 

### of the families Clupeidae, Cyprinidae, Catostomidae, Ictaluridae, and Centrarchidae. Important forage species include gizzard and threadfin shad and several cyprinids. Creel census dataindicatethat Lake Wylie supports a better-than-average sport fuhery ;major species

were crappie, bluegill, largemouth bass, and catfish (IndustrialBio-Test Laboratories, Inc., 

### 1974).

Marshall Steam Station and Oconee Nuclear Station Marshall Steam Station 

### is located on Lake Norman in Catawba County, N. C.; Oconee Nuclear Station is located

on Lake Keowee in Oconee County, S.C. Each is a hypolimnetic reservoir (skimmer-wall) intake design. At both sites condenser coolingwater is drawnfromanintake

Edwards, Hunt, Miller, and Srvic: Duke Power Company, Environmental SciencesUnit, Charlotte,North Carolina.
I 

### I 

### 373TABLE 1 Intake Velocities (cmlsec) atFour Duke Power Company Generating Facilities Pumping Maximum

mode Full pond drawdown

Allen SteamStation Units 1 and2

1Pump 4.57 7.62 2 pumps 7.62 12.50 Units 3,4, and 5 1Pump 6.70 11.28 2 pumps 11.28 18.90
Marshall Steam Statioh Units 1 and 2

1 Pump 7.32 13.41 2 pumps 10.67 18.90 Units 3 and 4

1 Pump 5.49 9.75 2 pumps 9.14 16.15 3pumps 11.89 21.03
Buck Steam Station Units 1 and 2

1Pump 79.25 79.25 2 pumps 73.7 6 73.76 Units3,4,5, and 6 1 Pump 50.60 82.90 2 pumps 38.10 61.57
Oconee Nuclear Station Units 1,2, and 3 2 pumps 36.27 51.51 3 pumps 31.70 45.11 4 pumps 26.80 38.05

cove separated from the main body 

### of the lake by a skimmer wall, which is a solid concrete structureextending from the surface to a depth 

### of 20m, wellbelow the depth 

### of the summer thermocline. During 

### the summer, lowtemperature hypolimnetic water is drawn intothe cove and provides efficient condensercooling. At both Marshall and Oconee, intake structures are located at the extreme back 

### of the intake coves; water flow is fromthe skimmerwaII to the intake structure. Marshall Steam Station is a four-unit cod-burning facility with an output capacity 

### of 2025 Mw(e). The total capacity of the 

### 10intake pumpsis 65m3/sec. TheMarshall intake includes 16 stationary intake screens, and the skimmer wall separates the intake cove (-81 ha) from the main 

### body 

### of Lake Norman 

### (Fig 1). The fishery 

### of Lake Norman 

### has been investigated 

### by the North Carolina Wildlife Resources Commission 

### (Miller and DeMont, 1974)and the Environmental Sciences Unit at Duke Power Company (Duke Power Company, 1974). Forty species 

### of fishes representing 10 fadies were reported in these two studies. Lake Norman supports several species 

### of Cyprinidae, Catostomidae, Ictaluridae, 

### 374 Edwards,Hunt,Niller,

### und Sevic 

# t E YADKIN RIVER

0 

### 2 FLOW ____) 

# 1
-
- 123456 BUCK STEAMSTATtON

LAKE WYLIE. CATAWBA RIVER 

# t 1 FLOW E T 

# +

12345

FIG. 1 Intake structure locations at three power-plant sites. {a)river intake design. (b)epilimnetic reservoir intake design. (c)hypolirnneticreservoir (skimmer-wall) intake design.

and Centrarchidae. Valued sport species are sunfish, crappie, largemouth bass, white 

### bass, and striped bass. Threadfin shad have been introducedand havebecome well established as a forage species. Cove rotenone datacollected during the summers 

### of 1973 and 1974 provided a mean biomass estimate

### of-123 kg/ha. Oconee Nuclear Station has three generatingunitswith

a total output capacity 

### of 2625Mw(ej. The intake structure includes 24 stationary intake screens and 12intake pumps

### with a total capacity of 128m3/sec.Theintake cove at Oconee (-25 ha) is similar to the Marshall intake cove shown in Fig. 

### 1. Since June 1972, the Southeast Reservoir Investigations, Bureau 

### of Sport Fisheries and Wildlife, has been investigating the fishery of Lake Keowee in connection with 

### the operation 

### of Oconee Nuclear Station (Southeast Reservoir Investigations, 1972). Electrofishing and $&net

I I

Idata have accounted for 41species representing 9 families. Centrarchidae, Ictaluridae, and Catostomidae made up the majority of the total catch. A creel census conducted between July and September 1973 indicated that largemouth bass, bluegdl, andcrappie are important sportfBhes. Yearly estimates 

### of fish biomass from cove rotenone data from 1972 to 1974have averaged -67.4 kg/ha. Threadfin shadwere stockedin February 

### of 1974and apparently have become established as a forage fish.


### Buck Steam Station Buck Steam Station, a river intake design located in Rowan County, 

### N. C., draws condensercooling water from the Yadkin River near its mouth at 

### High Rock Lake. A six-unit coal-burning facility, Buck began operation 

### in 1926 and has a totalcapacity 

### of488Mw(e). The intake structure, which is made up 

### of 10pumps capable of drawing water ata maximum rate 

### of 21m3/sec, is located on the shoreline of the river and parallel to the river flow (Fig. 

### 1).Intake velocities at Buck are shown in Table 

### 1. An environmental investigation 

### of the Yadkin River, including a field study 

### of the river's fishery, has been conducted 

### by Duke Power Company (1975). Forty species representing 

### 11 families were collected fromOctober 1973 to September 1974. Collections from 

### all stations sampled

were composed primarily of the families Cyprinidae, Ictaluridae, Centrarchidae, and Clupeidae. Important sport fishes in the area include several species 

### of centrarchids, as well as white and channel catfish. Abundant forage species

are gizzard shad, satinfii shiner, and whitefin shiner. In contrast to other sites, threadfin shad arenot abundant in the area.


### MATERIALS AND METHODS Duke Power Company steam stations have two basic types of intake structures. Marshall Steam Station and Oconee Nuclear Station have stationary intake screens, which must be removed with a crane for each inspection. Allen and Buck Steam Stationshave traveIing screensmade up of several panels'mounted on a vertical conveyor-belt arrangement. Both traveling and stationary intake screens have 

### 1-crnmesh and are located behind vertical trashracks withbars at7.6-cm intervals. At sites having stationary intake screens, because 

### of the difficulty and time involved, one screen from each unit (25%of the total screen area)wasremoved andinspected at 2-week intervals. After each inspection screenswere cleaned thoroughly and replaced; each inspection represented the total impingement per screen occurring over a 2-week period. Fishes were identified, measured, and counted. When exceptionally large numbers of fisheswere collected, 

### totalnumberswere estimated from a subsample. At traveling screen sites, one screen associated with each generating unit was inspected regularly twice each week. During the normal screen-washing procedure, water jets are directed at screens as they are rotated. Debris and impinged fishes are washed off into a sluiceway that flows into the river orreservoir. For our inspechon screens were rotated, washed, andleft

### in place for 24hr. They were then rotated and washed again, and fishes and debris were collected in 

### a wire-mesh catch basket placed in the sluiceway. Fishes collected were preserved in 

### 10%formalin ' and brought back to the laboratory, where they were identified, measured, andcounted. At Allen Steam Station impingement studies were conducted for 

### 1year by Industrial Bio-Test Laboratories, Inc. (Krueger, Rice, and Otto, 1974). Three 8-hr 

### subsamples were taken over a 24-hr sample period every 

### 2 weeks. 

### All screenswere sampled oneach sample date. At some steam stations, when river conditions and heavy accumulation of debris have necessitated early cleaning of intake screens, total sample periods have been less than 24hr. An effort was made at 

### all stations tobe

### as consistent as possible in the actual screen samplingandthe total time screens were left stationary. Occasionally alternate screens were sampled because 

### of operatingdifficulties

orrequired repairs. Fish impingement has been expressed as total seasonal impingement by species (fish per screen per day) and es+mated impingement rates (total daily impingement). Estimated rates were derived by extrapolating collected data (fish per representative intake screen per sample period). Fishes that were unidentifiable because 

### of decomposition were listed as such;otherwise, identifications were made tolowest possible taxon. Intake-approach velocities were calculated from total pump flow and actual area of intake-screen openings. Intake temperatures were monitored hourly ateach station with a thermocouple or a resistance temperature device. To satisfy required assumptions of analysis ofvariance,

wetransformedrawdatacollectedatMarshall Steam Station using common logarithms. A two-way analysis 

### of variance (ANOVA) (Sokal and Rohlf, 1969) was then used to test for differences in impingement rates between units and

seasons. Duncan's multiple range testwas used todetermine relative differences between units (SteeI andTorrie, 1960).



### RESULTS 

### Allen Steam Station At Allen Steam Station, 55,762 fishes representing 

### 19 taxonomic groups 

### (18speciesplus 

### 1 genus) were collected from October 

### 1973 through September 1974 (Table 2). Gizzard shad, threadfin shad, channel catfish, and bluegill

were collected most consistently and were present in samples during each month 

### of the study. Threadfm shad accounted for the majority of fishescollected (54,971)and comprised 98.6% of the total catch. Of these, 91.8% were collected from November 1973throughJanuary 1974. &, the data in Table 2 indicate, rates 

### of fish irnpingemcnt at Allen were lowest in spring and summer and highest in fall and winter. The estimated number of fish impinged per screen per day, calculated ona seasonal basis, ranged from 13 in spring 1974 to 349 in 

### fall 1973.ThisTABLE 2 Seasonal Summary of Fish Impingement atAllen Steam Station*

Commonname Scientificname Oct.--Dec. 1973 Jan.-Mar. 1974 Apr.-June 1974 Jd.-Sept. 1974
Gizzard shad Threadfinshad Channel catfish Bluegill Miscellaneous

### t Dorosomacepedianum 59 26 43 70 Dorosomapetenense 31,295 20,219 836 2621 Ictaluruspunctatus 7 45 20 12 Lepomis macrochirus 31 24 168 89 20 34 71 72 Totalnumber offish collected 31,412 20,348 1138 2864 Estimated fishlscreenlday 349 226 13 32 Estimated totalfish/day 5,235 3,390 195 480

*Fish per screen per day and total fEh per day were determined from the number of fish impinged on all intake screens. All
screenswere sampled from October 1973to August 1974by IndustrialBio-TestLaboratories, Inc. Total impingementin September 1974was estimated from samples collected from five representativescreensby DukePower Company,EnvironmentalSciences Unit (totalnumber ofscreensat AIlenis 15). tMiscellaneous fish, listed from most to least frequently impinged, are: white catfish, Ictalurw catus;yellow perch, Perca flmescens;pumpkinseed, Lepomis gibbosus;warmouth, Lepomis gulosus; redbreast,Lepomis auritus;catfish,Ictalurus sp.; redear, Lepomis micsolophw; silvery minnow, 

### Hybognathus nuchalis; brown bullhead, Ictalurus nebulosus;golden shiner, Notemjgonus cryzo&ucar;mosquitofish, Gambusia affinis; white bass, Morone Chrysops; satinfin shiner,Notropis andostunus;black crappie, Pornoxisnigromaculatus;and largemouthbass,Micropterus salrnoides.

corresponds to a rangein

### total 

### daily impingement of 

### 195 to 

### 5235 fEhes for spring and 

### fall, respectively. An estimated 

### 898,911 fishes were impinged at Allen throughout the study period.



### Oconee Nuclear Station At Oconee Nuclear Station, 

### .241,697 fishes, including 

### 12 taxonomic groups 

### (9 species and 

### 3 genera), were collected on representative screensfrom

### July 1974 through May 

### 1975 (Table

### 3). Threadfin shad, stocked 

### in February 

### 1974, were not represented 

### in the samples to any extent until November 

### 1974. Prior to this, yellow perch and blue$ comprised the majority 

### of identifiable fish 

### (22.2% and 

### 72.6%,respectively). 

### By December threadfin shad had become the dominant species collected and remained 

### so through winter 

### 1975. Overall,threadfin shad accounted 

### for 

### 49.3%

### of the total identifiablefish collected. Yellowperch, blue*, and threadfin 

### (4 to

### 6cmlongandweighing

### -2.1 

### g each) were the most commonly impinged fishesatOconee. Impingement rates were lower 

### in spring and summer than 

### in 

### fall and winter. The estimated number 

### of 

### fish impinged per screen per 

### day ranged from 

### 15 in summer 

### 1974 to 

### 393 in winter 

### 1975. This represents an estimated total 

### daily impingement rate 

### of 372in summer 

### 1974 and 

### 9425 in winter 

### 1975. An estimated total 

### of 1,064,262 fishes were impinged at Oconee throughout the study period.



### Marshall Steam Station Impingement data collected at Marsh& Steam Station 

### from April 

### 1974 through March 

### 1975 are presented 

### in Table 

### 4. Fishes collected at Marshall have been categorized into 

### 14 ~OUPS, including 

### 10 speciesand 

### 4 genera. A total of 

### 974,896 fBhes were collected on representative screens throughout the study period. Impingementrates at Marshall


### 376 Edwards,Hunt,

### Miller,

### and Sevic were highest in 

### fall 1974 and winter 

### 1975(1518and 

### 1108 fEh/screen/day, respectively). An estimated 

### 54 fuhlscreenl day were collected in spring 

### 1974, and 

### 6 fish/screen/day

were collected in summer 

### 1974. Total 

### fish impinged per day rangedfrom 

### 96in summer 

### 1974to

### 24,090 in

### fall 1974. An estimated 

### 3,769,300 fishes were impinged at Marshall throughout the study period. Approximately 

### 9vo 

### of this total was made up of threadfin shad and

### Dorosoma sp-The size range 

### of the 

### Dorosorna suggests that they also were threadfm shad. The majority 

### of the shad were collected in November and December 

### 1974 andJanuary 

### 1975. Analysis of variance indicated that significant 

### differences existed in the number of fishes collected among units 

### (P<O.O1) and among winter, spring, and summer'

seasons 

### (P

# <0.01).Fall datawere not included 

### in statistical analyses because unit 

### 3 intake pumps 

### did not operate for several days. Duncan's multiple range test 

### has shown that the mean number 

### of fishes collected at each unit is significandydifferent from means at

### all other units.



### Buck Steam Station Impingement rates were low at Buck Steam Station (Table 

### 5) despite relatively high intake velocities (Table 

### 1). A total 

### of 467 fishes was collected from representative

screens from 

### Jdy 

### ,1974 through June 

### 1975. Fishes impinged atBuck,identified tolowest possiblema,comprise 

### 7 speciesand 

### 2 generagroups. Estimated total daily impingement at Buck was less than 

### 1 fish/day in 

### both 

### falland winter 

### 1974.The estimated total 

### fish collected per day was highest in summer 

### 1974 (42.5 fish/day) and intermediate in spring 

### 1975 (1.3 f&h/day). Fish mortalities occurring upstream are the suspected cause 

### ofrelatively 

### high numbers 

### of

### fish collected duringthe summer period.

I 

### I

iTABLE 3 Seasonal SummaryofFish Impingement atOconee Nuclear Station*

Commonname Scientific name JulySept. 1974 0ct.-Dec. 1974 Jan.-Mar. 1975 Apr.-May 1975

Threadfm shad Dorosomapetenense 0 9,949 107365 1426 Bluegill Lepomis macrochirus 2749 183 365 82 Yellow perch Percafrauescens 757 182 4,164 874 Unidentifiable 5005 3,157 99,653 5215 Misceilaneoust 24 26 14 7
Total number of fish collected 8535 13,497 212,061 7604 Estimated fishlscreen/day 15 24 393 28 Estimated total fishlday 372 587 9,425 676

~ ~~ +Fish per screen per day and total fish per day were estimated from the number of fish impinged on six representative intake screens; totalnumber ofscreensatOconee is 24. 

### tMiscellaneous 

### fish, listed from most to least frequently impinged, are: gizzard shad, Dorosoma cepedianum; crappie, Pomoxis cpi.; white crappie, Pomoxisannulark;catfish, IctaIunrs sp.; pumpkinseed, Lepomisgibbosus;warmouth, Lepomisgulosus; carp,Cyprt:us carpio;largemouth bass,Micropterussalmoides;and trout, Sdmosp.

TABLE 

### 4 Seasonal Summary ofFish Impingement at MarshallSteam Station*

Common name Scientificname Apr.-June 1974 July-Sept. 1974 0ct.-Dec. 1974 Jan.-Mar. 1975

~~ Gizzard shad Dorosoma cepedianum 1,108 49 69 40 Threadfm shad Dorosomapetenense 1,995 1879 181,109 393,623 Shad Dorosoma sp. 6,780 70 377,419 0 Catfish Ictalurn sp. 4 99 22 0 Yellow perch Percajlavescens 722 19 42 10 Unidentifiable 4,414 22



### . 17 5,356 Miscellaneoust 17 6 3 2 Total numberoffish collected 15,040 2144 558,681 399,031 Estimated fish/screen/day 54 6 1,518 1,108 Estimated total fish/day 864 96 24,090 17,728

*Fish per screen per day and total fish per day were estimated from the number of fishimpinged on fourrepresentative intake screens;total number of screensatMarshallis 16. tMiscellaneous fish, listed from most to least frequently impinged, are: minnows, Nohopissp.; black crappie, Pomoris nigromacukztus; white crappie, Pomoxis annularis; largemouth bass, Microptern salmoides;bluegill, Lepomis macrochirus; sunfish, Lepomissp.; stripedbass, Morone saxatilis;carp, Cyprinus cmpio;and golden shiner,Notemigonus crysoleucar.

TABLE 5 SeasonalSummary of Fish Impingement atBuck Steam Station*

Common name Scientificname JutySept. 1974 0ct.-Dec. 1974 Jan.-Mar. 1975 Apr.-June 1975

Gizardshad Dorosomacepedianum 391 0 1 0 Threadfm shad Dorosomapetenme 1 0 0 10 Shad Dorosomasp. 33 0 0 2 Miscellaneoust 14 0 1 14 Totalnumber of fish collected 439 0 2 26 Estimated fish/screen/day 4.25 0 <0.1 0.13 Estimatedtotal fishlday 42.5 0 <0.1 1.3

~~ ~ ~~ *Fish per screen per day and total fish per day were estimated from the number of fishimpinged on fourrepresentative intake screens;total number of screens at Buckis 14. tMiscellaneous fish, listed from most to least frequently impinged, are: white catfish, Ictalurus catus; bluegill, hpomis macrochirus; catfish, Ictalurussp.; channel catfish, IctaIurn punctatus; brown bullhead, Ictalurus nebuZosus; and black crappie, Pomoxisnigromacuhtus. 

### Evaluation 

### ofI&ingernent ofFishes 377- An estimated 4069 fishes were impinged at Buck throughout the study period. Gizzard shad, threadfin shad, and

### Dorosornasp. made up 93.8% of

## dl fish collected.

. 

### DISCUSSION Intake Velocity Intake.velocities vary considerably among the stations at which impingement has been monitored (Table 

### 1). Velocities fluctuate 

### with water level and the number of intake pumps in operation. Ranges 

### of possible intake velocities for Marshall and Allen Steam Stationsare similar and are the lowest ranges of

### the foursites. Intakevelocities at Oconee Nuclear Station are intermediate, and those at Buck Steam Station are the highest encountered 

### in the study. Impingement rates atthese sites cannotbe explainedon the basis 

### of intake velocity. Despite the high intake velocities at Buck, the rate of fish impingement at this site

was lowest. 'The highest number 

### of fish were collected at Marshall and Allen, wherevelocities were relatively low. Average intake velocities throughout the study period

were calculated for each 

### of the four generating units at Marshall Steam Station, and corresponding impingement rates were determined (Fig. 

### 2). Velocities were calculated

on the basis 

### of thenumber 

### ofpumpsin operation;constant water level (full pond) was assumed. Although intake velocities are similar for each 

### of the four units at Marshall, significantdifferences in rates 

### ofimpingementoccurred.

i' At Allen the highest numbers of fish were collected at units 

### 1 and 

### 5, even though these units representthelowest and highest velocities, respectively, at this station. These 

# !,& data indicate that impingementrates vary significantthat

### cKk~emces~c~u~&~depemfmnaf veiocines. * ' intaKe *


## ..

Intake Structure

### Design The intake design at Buck Steam Station may be a 

# - f g to low impinmment ra-t m a j o L 

## ..

d site. The intake structure is parallel to and relatively iiush 

### with the river bank (Fig. 

### 1). This design reduces the possibility 

### -of eddy currents, which may concentrate fish and subsequently trap them 

### in the intake 

### (U. 

### S. Environmental Protection Agency, 

### 1973). Impingement 

### of both threadfin shad and all other species combined is considerably higher at Marshall than at Buck despite Marshall's relatively low intake velocities. It has been established that variation in impingement rates among units 

### 1 to 4 at Marshall is apparently not related to intake velocity. The shape of the intake cove probably

causes the high impingement-rates at unit 4 and the consecutively decreasing rates at units 

### 3, 2, and 1 (Fig. 

### 2). As shown in 

### Fig. 1, the intake structure at Marsh& is located at ehe extreme back of a cove. Currents create eddys next to screens associated 

### with unit 4, and 

### fish apparently concentrate in these eddy currents and become susceptible toimpingement. Variations in impingement rates among units at Allen

were also observed. These have been attributed, in part, to 

### 3

### 78 Edwards,Hunt,

### Miller, 

### and 

### Sevic v = 8.2

UNlT 1 UNIT 2 UNIT 3 UNIT 4

FIG. 2 Impingement rare and mean daily velocity (Y), in cmlsec, for the four units at Marshall Steam Station from Apr. 30, 1974, through Feb. 4,1975.

the relative position 

### of intake screens 

### (Fig. I).Consistently higher numbers 

### of 

### fEh were collected at units 

### 1 and 

### 5, probably because 

### ofthe extremeupstream and downstream position 

### of these 

### units. It 

### is likely that eddy currents on either side of the intake structure attract 

### fish, which subsequently become impinged on.

### the nearest intake

screens (those associated 

### with units 

### 1and 

### 5).

Resident 

### Fish Populations Field fishery investigations in the vicinities of Allen, Buck, and Marshall Steam Stations and Oconee Nuclear Station have indicated

are low, the areas all cases, conected onintake screens.



# -

- .. - - I 

### IAt Allen, 

### 24 species were collected in the area duringa field study on Lake 

### Wylie; 16 

### of these were collected from the traveling screens at the intake. Silvery minnows and mosquito fish, which were collected onintake screens, were not represented in field collections, and eight species were collected 

### in the field which were absent from screen samples. At Lake Keowee, 

### 33 species collected in the field

were not collected on intake screens atOconee; all species impinged were represented in field samples. Of the 40 species reported from Lake Norman, only 

### 10 were impinged at Marshall. 

### At Buck, 100-fisheswere collected immediately above and beIow the intake structure 

### in -40min on a single day in February; these included 16 species representing

### 7 families. There were nofishimpinged at Buck in February, however, and only 

### 7 species were impinged throughout the entire study.



# - That the species collected on intake screens were not

represented in numbers proportional to the field samples suggests further that susceptibility to impingement is, to



# - some degree, species specific. Data collected from the

intake cove at Marshall provide an example. Electrofishing samples were collected in theintake cove on Feb. 21, 1975, in an effort tto compare the numbers and species of fishes impinged with those present in the intake cove. Samples collected in 

### snnalIinlets above the intake structure provided 

### 182 fishes, representing 

### 12 species and 

### 5 families. Sport fishes, including centrarchids, percids, and percichthyids, made up 39.5% of the catch. Threadfin shad accounted for 52.7% of all fish collected; all others were carp. Impingement data collected atMarshall in February indicate a total of 166.1 15 fishes impinged on four representative intake

screens. Threadfin shad accounted for 99.9% (166,095) of the total; others included gizzard shad and one white catfish.


### Temperature Data collected at

### Allen andMarshall Steam Stations and Oconee Nuclear Stationhave shown seasonal trends in

### total



### , numbers of fish impinged. Impingement rates have generally been relatively high in late fall and winter and low throughout the rest 

### of the year. This trend resulted from the collection 

### of large numbers of threadfin shad when temperatures were low. The relationship between temperature, the impingement of shad, and the impingement of all other species at Marshall is shown in Fig. 

### 3.Threadfin shad were collected
at relatively high rates beginning in November, when water temperatures droppedto -13°C. Threadfin shad are known to be susceptible to low temperatures, andmortalities have been reported below 9°C (Strawn, 1963). Data presented here indicate that threadfin may become stressed at temperatures considerably higher than 9°C and are then susceptible to impingement because of their inability to resist intake currents. At Marshall, the impingement of species other than threadfin shad appears to be unrelated to temperature. Other species impinged, which have wider 10'

25

1

### oL

20 

# 6103 0
LL UJ lA E 0 3 rn Ia w 5," m W I a. 3102 

### z z wI

### I O 10' 

# -.......

1. .*e



# . . 

# . . .I...

10 3014281325 9 22 620 317 1152912261123 8217 18 6 18 APR. MAY JUNEJULYAUG.SEPT. OCT. NOV. OEC. JAN. FEE. MAR. 1974 1975

FIG. 3 Fish impingement at Marshall Steam Station, in mean number of fish per screen per day, relative to water temperature. Shad,

### -. Otherspecies,

## ---

## -.Temperature,.



### . .

## ..

ranges of thermal tolerance, are apparently not stressedby the ambient winter temperatures 

### of Lake Norman. A similar situation existed at Allen Steam Station. Of the total number of threadfin shad impinged there (98.8% of total fishes collected), 

### 95.4% of the mortalities were attributed to lowwinter temperatures. After being introduced into Lake Keowee for the first time in February 1974, threadfin shad made up the majority 

### of the fishes impinged at Oconee Nuclear Station in the winter 

### of 1974-1975. Low winter temperatures are suspected as the cause. The impingement 

### of threadfin shad at these sites does not appear to be a major causeofmortalitybut

### is rather an indication ofnatural mortality of the species. 

### *.

-.-A *.-

- Summarizing the major points discussed, we conclude:

* 1.Threadfin shad made 

### up the majority of fish collected on intake screens. Sport fishes and other valuable species were considerably less susceptible to impingement. 2. In 

### all cases the number 

### of fish species impinged at specific sites was fewer than the number collected during concurrent field investigationsin the study area. 

### 3.Overall, relatively large numbers of fuh were COIIected on intake screens duringlate 

### fall orwinter, Thiswas caused by the susceptibility 

### of threadfin shad to low 

# I

temperature. The majority 

### of the threadfin shad were apparently stressed or dead before they were collected on intake screens. 

### Evaluation ofI&in.ernent 

### of

### Fishes 379E 4. Intakevelocitywas not a determiningfactor concern­ 

# \ing relative rates ofimpingement among the sites discussed. 

### 5. Intake design, specifically the position of the intake r. structure relative to the cooling-water source, signiticantly affected impingement rates. 

### 6.The skimmer walls at Marshall Steam Station and



## . Oconee Nuclear Station have not provided a deterrent to

L theimpingement 

### of fish. 

### 7. In view of the speciesand numbers of

### fshaffected,

### it 

### is doubtful that impingement at these sites has had significantimpact on resident 

### fish populations. 

# -. ACKNOWLEDGMENTS This research would nothave been possiblewithout the cooperation of the superintendents andstationpersonnel at Duke Power Company’s Allen, Buck, and Marshall Steam Stations and Oconee Nuclear Station. We appreciate the constructivle reviews offered by 

### W. 

### D. Adair and 

### L. L. Olmsted and the preparation 

### of the 

### final manuscript by StanMcCorkle.



### REFERENCES Duke Power Company, 1975, Environmental Report, Project 81, Perkins Nuclear Station,Volume 1,Charlotte,N. C.
-, ’ 1974, Environmental Report, McGuire Nuclear Station, Units 1 and 2, Operating License Stage, Volume 1,Charlotte, N. C. Edsall, T. A., and T. G. Yocom, 1972,ReviewofRecent Technical In

formation Concerning the Adverse Effects of Once-Through



### 380 E,dwards,Hunt,

### Miller,

### and Sevic Cooling on Lake Michigan, U. S. Fish and Wildlife Service, Bureau of Sport FisheGes and WiIdlife, Great Lakes Fishery Laboratory, Ann Arbor, Mich. Industrial Bio-Test Laboratories, Inc., 1974, A BaselineI Predictive Environmental Investigation of Lake Wylie, September 1973-August 1974, Report to Duke Power Company, Charlotte, N. C. Krueger,J. F., J. 0. Rice, and R. G. Otto, 1974,Screen Monitoring at Allen Station, September 1973-August 1974, Industrial Bio-TestLaboratories, Inc., Charlotte, N. C. Landry, A. M., Jr., and K. Strawn, 1974,Number ofIndividuals and Injury Rates of Fishes Caught on RevolvingScreensatthe P. H. Robinson Generating Station, in Proceedings of the Second Workshop on Entrainment and Intuke Screening, L. D. Jensen (Ed.), pp. 263-271, Research Project RP-49. Report No. 15, TheJohns Hopkins University Press, Baltimore, Md. Miller, R. W., and D. J. DeMont, 1974, Fisheries Research, in Environmentul Responses to Thermal Dischargesfrom Marshall Steam Station, Lake Nomn, North Carolina, L. D. Jensen (Ed.), pp. 187-216, Research Project RP-49, Report 11, The Johns Hopkins University Press, Baltimore, Md. Sokal, R. R., and F. J. Rohlf, 1969,Biometry, W. H. Freemanand Company,San Francisco. Southeast Reservoir Investigations, 1972, Annual Report, U. S. Bureau of Sport Fisheries and Wildlife,Clemson, S.

### C. Steel, R. G. D., andJ. H. Tome, 1960,Principles andProcedures of Statistics, McGraw-HillBook Company, Inc., New York. Strawn, K., 1963, Resistance of Threadfin Shad to Low Temperatures, Proc. Annu. Conf.Southeast.Assoc. Game Fish Comm., 17: 290-293. U. S. Environmental Protection Agency, 1973, Development Document for Proposed BestTechnology Availablefor Minimizing Adverse Environmental Impact of Cooling Water Intake Structures,ReportNo. EPA44011-741015, Washington, D. C.-__I__ .-­ d' ti 

# 1

CONF-750425



# 1 

# Thermal 

# Ecology

# II

Proceedings 

### ofa symposium held at Augusta, Georgia April 

### 2-5,1975

Sponsored by

Savannah River Ecology Laboratory Institute 

### of

### Ecology,University 

### of Georgia

Division

### of Biomedical and Environmental Research Energy Research and Development Administration



### Edited by


### GeraldW.Esch Wake Forest University


### RobertW. McFariane Savannah RiverEcology Laboratory



### 1976

Pubfished by Technical Information Center 1 Energy Research and Development Administration 

### I