CLAYTOR HYDROELECTRIC PROJECT

FISH ENTRAINMENT AND IMPINGEMENT ASSESSMENT

January 2009 
CLAYTOR HYDROELECTRIC PROJECT

FISH ENTRAINMENT AND IMPINGEMENT ASSESSMENT

Prepared for 

APPALACHIAN POWER COMPANY 

Hydro Generation Department 

40 Franklin Road 

Roanoke, VA 24011 

Prepared by 

NORMANDEAU ASSOCIATES, INC. 

1921 River Road 

Drumore, PA 17518 

and 

25 Nashua Road 

Bedford, NH 03110 

R-20979.001

January 2009 
CLAYTOR HYDRO FISH ENTRAINMENT & IMPINGEMENT ASSESSMENT

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Table of Contents 

Page 

1.0 INTRODUCTION AND BACKGROUND............................................................................1

2.0 PROJECT DESCRIPTION AND GENERAL APPROACH ..............................................2

2.1 CLAYTOR LAKE DESCRIPTION AND CHARACTERISTICS...................................................2

2.2 PROJECT FACILITIES.........................................................................................................2

2.3 FISH POPULATIONS AND MANAGEMENT SPECIES ............................................................3

2.4 SPECIES OF SPECIAL CONCERN ........................................................................................7

2.5 CURRENT EVIDENCE OF ENTRAINMENT AND IMPINGEMENT PROBLEMS.........................7

3.0 SWIM SPEED LITERATURE REVIEW AND FIELD VELOCITY DATA....................9

3.1 FISH SWIM SPEEDS ...........................................................................................................9

3.2 FIELD STUDY OF INTAKE VELOCITY ..............................................................................16

3.3 FIELD VELOCITIES VS FISH SWIMMING CAPABILITIES...................................................20

4.0 COMPARATIVE ANALYSIS OF SIMILAR PROJECTS...............................................23

5.0 ENTRAINMENT ASSESSMENT........................................................................................26

5.1 CHARACTERISTICS AND BEHAVIOR OF SELECTED FISHES.............................................26

5.2 REVIEW OF ENTRAINMENT RATES DEVELOPED BY EPRI (1997) ..................................31

5.3 BLADE STRIKE AND CAVITATION POTENTIAL OF EXISTING UNITS ...............................36

5.4 TURBINE PASSAGE SURVIVAL ASSESSMENT..................................................................37

6.0 OVERALL ENTRAINMENT ASSESSMENT ...................................................................42

7.0 CONCLUSIONS ....................................................................................................................46

8.0 LITERATURE CITED..........................................................................................................47

8.1 SWIM SPEED LITERATURE IN TABLE 3-1 AND SECTION 3.1 ...........................................47

8.2 FISHES AND ENTRAINMENT/IMPINGEMENT LITERATURE ..............................................49
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List of Figures 

Page 

Figure 2-1. Claytor Hydroelectric Project location in Virginia...............................................................4

Figure 2-2. Representative drawing of Claytor Hydro Project intake area.............................................6

Figure 2-3. Reference photo of Claytor intakes and spillway area during project construction............7

Figure 3-1. (T110) Color-contour section for tangential line (parallel transect) 

approximately 40 feet off the intake wall for 10,000 cfs condition. Box outline = 

intake centerline 44 feet deep..............................................................................................19

Figure 3-2. (N2A10). Color-contour section for normal line (perpendicular transect) in front 

of Unit #2 for the 10,000 cfs condition. Distance refers to distance from the face 

of the intake wall. Intake centerline is 44 feet deep. ..........................................................19

Figure 3-3. (T10-43) Synoptic velocity vectors 43 feet below the surface during the 10,000 

cfs condition. Intake bays are labeled U1, U2, etc. Scale arrow in lower left 

represents the length of a 1 ft/s vector. . .............................................................................20
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List of Tables 

Page 

Table 2-1. Reservoir and intake characteristics of the Claytor Hydroelectric Project..........................5

Table 2-2. Physical and hydraulic characteristics of turbines at Claytor Hydroelectric 

Project....................................................................................................................................6

Table 3-1. Reported swimming speed of fishes for the Claytor Hydroelectric Project ......................10

Table 3-2. Speed and direction values for each Fixed Station Profile.................................................18

Table 3-3. Speed and direction values for each Fixed Station Profile.................................................18

Table 3-4. Comparison of Claytor Lake intake velocity data and synthesis of fish swim 

speed information................................................................................................................22

Table 4-1. Location, hydraulic capacity and trash rack spacing of 43 sites included in the 

EPRI database......................................................................................................................24

Table 4-2. Size composition of entrainment catch by bar rack spacing (after Winchell et al. 

2000)....................................................................................................................................25

Table 5-1. Average entrainment densities for Claytor Hydro Project fish species of interest 

drawn from EPRI (1997) entrainment database. Annual density standardized and 

shown as number of fish per million cubic feet of water. ..................................................32

Table 5-2. Estimated entrainment losses for Claytor Lake fish species of interest. Annual 

density standardized and shown as number of fish per million cubic feet of water..........35

Table 5-3. Values of turbine parameters used in blade strike and survival estimates.........................36

Table 5-4. Predicted turbine passage survival at Claytor Project turbines based on the blade 

strike probability formula developed by Franke et al. (1997)............................................38

Table 5-5. Mean fish survival rates for Francis turbines and representative fish sizes in EPRI 

database (source: Winchell et al. 2000)..............................................................................39

Table 5-6. Site characteristics of empirical studies at Francis installations not reviewed in 

EPRI database. All studies performed using balloon tag technology...............................40

Table 5-7. Immediate (1-h) survival of representative fish species at Francis installations not 

reviewed in EPRI database. All studies performed using balloon tag technology...........40

Table 5-8. Estimated annual mortality due to turbine passage for Claytor Lake fish species 

of interest. The source of mortality rates was Winchell et al. (2000). ...............................41

Table 6-1. Comparison of factors that may influence entrainment or survival rates at Claytor 

Hydro Project.......................................................................................................................42
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1.0 INTRODUCTION AND BACKGROUND

The purpose of this report is to evaluate the potential for fish entrainment and impingement at the 

Claytor Hydroelectric Project (No. 739). Appalachian Power Company (Appalachian) is in the 

process of relicensing the Project using the Integrated Licensing Process (ILP) as defined by the 

Federal Energy Regulatory Commission (FERC). The ILP process involves many participants or 

stakeholders, including government agencies, local governments, non-governmental organizations 

(NGOs), the public, and other interested parties. Stakeholders were solicited for input on projectrelated issues that needed to be addressed during relicensing. 

An initial step was preparation and submittal of a Pre-Application Document that identified issues for 

study. Meetings with stakeholders and a work group guided study plan preparation during summer 

2006. A revised study plan was developed in October 2006, and approved by FERC letter in 

November 2006. 

This report addresses the likelihood of impingement, entrainment, and turbine mortality at the Claytor 

Project within a comprehensive review of relevant biological and physical factors at the project. The 

overall approach to this assessment is, for three tasks, to review existing literature relative to the 

species of management interest in the Project reservoir, and evaluate the potential for entrainment, 

impingement, and turbine mortality of fishes relative to Project facilities and structures. The three 

literature-based tasks are: 

1. Review swim speed and intake avoidance behavior literature for the identified fish 

species of principal management interest. 

2. Review existing evidence of impingement and entrainment problems associated with the 

current operating regime. 

3. Review other projects of similar design for impingement and entrainment problems and 

perform a comparative analysis to the Claytor Project. 

A fourth task represents a field component that will measure intake velocity profiles at various 

reservoir locations during maximum and “most efficient” hydraulic capacities. The field 

measurements and analyses will be used to establish threshold velocities relative to individual key 

species’ burst swimming ability identified in the initial literature-based task listed above. 

Via the study plan development process, eleven fish taxa have been identified as the basis for analysis 

in this report: juveniles and adults of striped bass, striped bass hybrids, gizzard shad, largemouth bass, 

smallmouth bass, spotted bass, white bass, walleye, black crappie, bluegill, and alewife. The Virginia 

Department of Game and Inland Fish (VDGIF) manages the reservoir’s fisheries. 
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2.0 PROJECT DESCRIPTION AND GENERAL APPROACH

The Claytor Project consists of a single conventional hydroelectric development located on the New 

River in southwestern Virginia (Figure 2-1). The Claytor Project dam is located at river mile (RM) 

252. Claytor Lake, the project reservoir, is a sinuous, riverine impoundment 21.7 miles long with a 

surface area of 1,810 hectares (4,472 acres) at a normal full pool of 1,846 ft NGVD (AEP 2006). 

Claytor Lake features one long, narrow tributary arm (Peak Creek) and several smaller tributary creek 

embayments located mainly in the lower half of the lake. Claytor Lake is located near Radford, 

Virginia and was impounded in 1939. More detailed information is provided below. 

2.1 CLAYTOR LAKE DESCRIPTION AND CHARACTERISTICS

Claytor Lake covers 4,472 acres with a maximum and mean depth of 115 ft and 49 ft, respectively 

(Table 2-1). Lake depth at the dam is reported at 124 ft. The main lake shoreline is rocky and steepsided. Shallow littoral areas are limited and generally confined to coves and lake areas upstream of 

Lighthouse Bridge (Figure 2-1) (Kohler et al. 1986; Rash 2003; Copeland 2004). Normal daily and 

weekly fluctuations in water surface elevation due to generation are less than 1 ft and 2 ft, 

respectively (Appalachian 2006). A fall drawdown of 5 ft is scheduled annually to permit shoreline 

landowners to access and repair dock supports, etc. 

Claytor Lake is considered moderately eutrophic (Copeland 1999), or nutrient enriched (Appalachian 

2006). Temperature and dissolved oxygen stratification occurs in summer, and is particularly strong 

during summers with low inflow. Water quality monitoring near Claytor Dam shows that dissolved 

oxygen depletion by late summer typically occurs between depths of 5 to 10 m (16-33 ft) to the 

bottom (Appalachian 2006). 

2.2 PROJECT FACILITIES

The Claytor Project powerhouse contains four Francis-type generating units each with a maximum 

and “most efficient” hydraulic capacity of 2,500 and 2,000 cfs, respectively (Table 2-1). Normal 

operating head (rated net head) is 116 ft (Table 2-2). The submerged intakes for the four units extend 

from 14 ft to 61 ft below the surface at normal full pool (Table 2-1; Figure 2-2). Each unit is screened 

by 0.5 in bar racks with 4.0 in clear spacing (Table 2-1). An historical reference photo is also 

provided for additional perspective showing the relationship among the intake area, spillway section, 

and lake bottom (Figure 2-3). 

Francis turbine runners (example below) consist of a series of vertically arranged, curved, fixed metal 

blades. Claytor turbine runners have 15 blades, or “buckets”. Water under high to moderately high 

pressure flows down through the blades and makes the turbine spin. Water flow from the intakes is 

delivered to the turbine through the penstock and is controlled by wicket gates (Claytor has 18 wicket 

gates) that surround the runner. Index testing determines the best wicket gate setting (percent 

opening, or most efficient setting) to deliver the optimum output. Water exits the turbine through a 

draft tube to the tailrace. Major parts of the runner are labeled in the figure below. 
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The approach velocity at the submerged intakes was estimated from calculations shown on the 

original project drawings. Estimated approach velocity in front of the trash racks, where fish initially 

encounter the project intakes, was calculated as 1.5 ft/s (Table 2-1). Velocity at the racks (located 

several feet inside the maximum intake opening) was calculated as approximately 2.4 ft/s. Water 

velocity accelerates during passage past the bar racks and through the penstocks as the penstock 

cross-sectional area further decreases. Additional intake velocity data obtained from planned field 

studies is discussed in Section 3.2. 

The calculated intake velocity information shown in Table 2-1 reflects data that were unavailable 

during study plan preparation. At that time an engineering analysis of intake flows was planned to 

augment the field intake velocity studies. The discovery of the project drawings that contained intake 

velocity estimates meant that the engineering analysis was no longer necessary. Thus, the engineering 

analysis portion of the study plan was dropped. 

2.3 FISH POPULATIONS AND MANAGEMENT SPECIES

Fisheries data for Claytor Lake were summarized for the Pre-Application Document by Copeland 

(2005). At least 24 native and introduced taxa characterize the known fish assemblage, although 

numerous additional species (e.g., minnows and darters) likely occur but are undocumented since 

sampling locations and sampling gear generally targets game fish for management assessments 

(Copeland 2005). Game species include largemouth bass (Micropterus salmoides), smallmouth bass 

(M. dolomieu), spotted bass (M. punctulatus), striped bass (Morone saxatilis), striped bass hybrids 

(M., chrysops x M. saxatilis), crappie (Pomoxis spp. mostly black crappie, P. nigromaculatus), and 

walleye (Sander vitreus). Striped bass, hybrid striped bass, and walleye historically have been 

maintained through stocking. Recent (since 2001) stocking densities for striped bass have been about 

13 to 17 fingerlings per acre, whereas hybrid striped bass stocking density has been 7.5 fish per acre 

over the same period. Walleye stocking was discontinued in 1996, then resumed in 2004 

(Appalachian 2006). Various sunfishes (Lepomis spp.) and catfishes, including channel catfish 

(Ictalurus punctatus) and flathead catfish (Pylodictis olivaris) are also abundant. 

The principal forage species include introduced gizzard shad (Dorosoma cepedianum) and alewife 

(Alosa pseudoharengus), in addition to young and smaller individuals of other species such as crappie 

and bluegill. Alewife was introduced concurrently with striped bass as pelagic forage in the late 

Crown

Blade (inlet edge) 

Water exit to draft tube 

Band 
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Figure 2-1. Claytor Hydroelectric Project location in Virginia. 
Claytor E&I Report.docm 12/09/08 5 Normandeau Associates, Inc. Table 2-1. Reservoir and intake characteristics of the Claytor Hydroelectric Project. Intake Elevations1 Trash Rack Bars Development Surface Area-full pond (acres) Maximum and (mean) depth-ft Normal Full Pond Elevation1 (ft) Top (ft) CL (ft) Bottom (ft) Unit Intake Width (ft)3 Individual Unit3 Screened Area (sq ft) Width (in) Clear Spacing (in) Number of Units Operating Desig

Hydrau

Capac

(cfs) 

Claytor Project 4,472 115 (49) 1,846.00 1,832.00 1,808.50 1,785.00 34.0 1,598.0 0.5 4.0 1 2,500 

34.0 1,598.0 2 2,500 34.0 1,598.0 3 2,500 34.0 1,598.0 4 2,500 

Project Totals 6,392.0 10,00

Notes: 1. All elevations are USGS datums. 2. Normal hydraulic capacity (turbine discharge) at most efficient point (MEP). 3. Each unit has two intake bays, each 17 ft wide x 47 ft high. 4. Calculated velocity in front of racks at intake plane. 
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Table 2-2. Physical and hydraulic characteristics of turbines at Claytor Hydroelectric 

Project. 

Unit Number Turbine Type 

Design 

Head (ft) 

Individual Unit

Design Flow (cfs)

No. of Blades/ 

Buckets 

Runner 

Diameter (ft) 

Runner 

Speed (rpm) 

1, 2 Vertical Francis 116 2,000 15 10.9 138.5 

3, 4 Vertical Francis 116 2,000 15 11.2 138.5 

Notes: 

1. Design flow (turbine discharge) at most efficient point (MEP). 

2. Runner diameter (ft) at inlet. 

Figure 2-2. Representative drawing of Claytor Hydro Project intake area. 

1960s (Kohler et al. 1986). Gizzard shad were introduced by anglers in the late 1980s (Copeland 

1999). 

Recreational fishing for the three black bass species in Claytor Lake comprised 58% of the 330,000 

angler hours expended in the most recent creel survey (Copeland 2000). Angling for Morone spp. 

formed nearly 10% of targeted effort, followed by effort for catfishes (7%) and panfish (5%). Angler 

catch was dominated by bluegill, followed by the three black basses. Angler harvest was also 

principally bluegill, followed by channel catfish and black crappie. In terms of retention rate, 

however, anglers favored channel catfish (81%), walleye (73%), and flathead catfish (67%). 
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Figure 2-3. Reference photo of Claytor intakes and spillway area during project construction. 

2.4 SPECIES OF SPECIAL CONCERN

No rare, threatened, or endangered fish species are known from Claytor Lake (Appalachian 2006). 

2.5 CURRENT EVIDENCE OF ENTRAINMENT AND IMPINGEMENT PROBLEMS

2.5.1 Brief Description of Operations 

The Claytor Project is operated primarily to provide peaking power, particularly during the cooler 

months from mid-October through mid-April. During the warmer months from mid-April through 

mid-October, considered the prime recreation season, peaking is voluntarily limited (pool levels are 

maintained within 1 ft of full pool) to stabilize river levels for water-based recreation in the New 

River downstream of the dam. Additionally, water levels in the lake during 15 April to 15 June are 

maintained between 1,844 ft and 1,846 ft (full pond) to promote fish reproduction in shallow 

shoreline areas. 

2.5.2 Evidence of Entrainment and Impingement Problems 

Direct evidence of fish emigration out of Claytor Lake is limited to 1) capture by anglers and 

biologists of adult striped bass and striped bass hybrids in dam tailwaters and New River reaches 

further downstream (Copeland 1999; Kilpatrick 2003), 2) establishment of alewife in Bluestone Lake 
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at least 100 km downstream of Claytor Lake (Kohler 1982), and 3) capture of moribund alewife 

during passage through turbine penstocks (Boaze and Lackey 1974). Gizzard shad were also noted as 

emigrants out of Claytor Lake into the New River and downstream reservoirs by Bonds (2000). 

Among these lines of evidence, alewife clearly are subject to turbine entrainment due to passage 

through penstocks noted by investigations during the 1970s (e.g., Boaze 1972). For the other species, 

evidence is indirect since timing and routes of travel (turbine route or spill) have not been established. 

Survival of stocked striped bass during passage out of Claytor Lake has resulted in consistent sport 

fishing captures in the tailrace (primarily) as well as for a considerable distance downstream of the 

Project. However, radio telemetry and conventional tagging efforts by Kilpatrick (2003) were unable 

to determine whether striped bass caught in the tailrace were entrained as juveniles or adults, or the 

emigration route utilized by either life stage. Kohler et al. (1986) speculated that striped bass in 

Claytor Lake were susceptible to entrainment (= “emigration”) due to comparatively short water 

retention times. Alewife in Claytor Lake are prone to die-offs during cold winters (Kohler and Ney 

1981) and become susceptible to turbine entrainment as they lose swimming ability in cold water 

(Boaze and Lackey 1974). 

Impingement of fishes on project structures (trash racks) has not been noted. Given the wide bar rack 

spacing (4-inch) and submerged intake depth (14 ft at top), fish impingement would be unlikely. Fish 

lacking the swimming ability to avoid the intakes would be expected to pass through the bar racks and 

not be impinged upon them. See Section 3.0 (below) for information on fish swimming capabilities. 
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3.0 SWIM SPEED LITERATURE REVIEW AND FIELD VELOCITY DATA

3.1 FISH SWIM SPEEDS

Avoidance of fish entrainment and impingement problems at water intakes is related to fish size and 

swimming performance (Castro-Santos and Haro 2005). We conducted a literature review of swim 

speed information for eleven fish species that inhabit the Claytor Hydro Project reservoir. The 

purpose was to compare available swim performance data for these species to in-situ measurements 

of current velocity obtained proximal to the project’s intakes (see Sections 3.2 and 3.3). 

Nine Claytor Lake fish species evaluated for swim performance represent the principal targets of 

fisheries management efforts by VDGIF as well as the focus of angler interest , including juvenile and 

adult striped bass and hybrid striped bass, largemouth bass, smallmouth bass, spotted bass, white 

bass, walleye, bluegill, and black crappie. Gizzard shad, alewife, and young bluegill and other 

Lepomis (sunfish) represent the principal forage for these game species. 

Three swim speed modes are generally recognized for fishes. Sustained swim speed is that maximum 

speed sustainable indefinitely, or for at least 200 min (Beamish 1978). Prolonged swim speed 

represents continuous, faster swimming that ultimately results in fatigue after at least 20 seconds. 

Laboratory testing of prolonged swim speeds for specific time intervals, frequently related to an 

expected or required time required to pass through fishways or culverts, results in estimates of critical 

swim speed (U), accompanied by a time stamp (e.g., Ucrit2 = maximum prolonged speed for 2 min). 

Burst, or sprint swim speeds, results in fatigue after no more than 15-20 seconds or less (Beamish 

1978; Bell 1991). Burst or sprint swim speeds (also startle, fast-start, or dart) are the fastest attainable, 

and are also those generally associated with fish well-being or survival (Beamish 1978; Wardle 

1980), as they are also related to a fish’s ability to capture prey, avoid predators, or in the present 

case, avoid water intake velocities or structural elements. Among the three swim speed modes, burst 

swim speed is harder to quantify in a laboratory, and, thus, fewer burst swim speed studies with 

adequate sample sizes are available (Castro-Santos and Haro 2005). 

Utilization of burst swim speed to avoid water intakes also implies the ability to use additional 

sensory mechanisms to properly detect and orient to the intake. Available stimuli near an intake, in 

addition to the physical structure, include turbulence, flow acceleration, pressure changes, sound, etc. 

(Castro-Santos and Haro 2005). The ability to utilize available cues to avoid intake structures or flow 

fields may be compromised by darkness or turbidity, for example, or reduced swimming ability as 

water temperatures approach or exceed cold water tolerances. 

The swim performance data in Table 3-1 clearly identify two trends for any given species. First, the 

swimming speed of larger juveniles or adult fish is faster than smaller juveniles. Second, water 

temperature also plays a role, and swim speed for several species appears maximized at 

approximately 20-30°C, typical late spring to fall ambient water body conditions. A reduction in 

swimming ability of 50% may occur at water temperatures outside a preferred range (ASCE 1995). 

Typically, reduced swimming ability only becomes a concern at water intakes in temperate latitudes 

as winter approaches. 

Swim speeds determined in the laboratory are typically measured by a distance rate, e.g., feet/sec, for 

a given fish length range or measure of length central tendency (mean, median). However, in 
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Table 3-1. Reported swimming speed of fishes for the Claytor Hydroelectric Project 

SWIM SPEED-feet per second-ft/s 

Species

Life 

Stage Fish Size

Max. 

Sustained 

Prolonged or 

Critical 

Burst or 

Startle Literature Source-Comments-Clarifica

Striped bass juv 1 in 0.83 Kerr 1953, cited in Clay 1961 

unknown 12-18L/sec Kerr 1953, cited in Hocutt 1973. 

juv 1-3 in ~1.9 from Figure 88 in Clay 1961--100% swimming @ 10 minutes. juv 32-63 mm FL 0.6-1.2 Tatham 1970-draft report; empirical data, 75 & 80F; 3 ppt salinity 

juv 50mm SL 1.91-1.98 2-min critical swim speed, U-crit: Young and Cech 1993. 

fry 0.5 in 0.6 est. from Bell 1991; dart speed maintained for 7.5 sec; fry 1 in 1.0 est. from Bell 1991; dart speed maintained for 7.5 sec; 

juv 2 in 2.0 est. from Bell 1991; dart speed maintained for 7.5 sec; juv 5 in 5.0 est. from Bell 1991; dart speed maintained for 7.5 sec; 

Striped bass adult 554 FL 14.9* Haro et al. 2004; @ 17.2C; upstream into fishway-max V tested Hybrid striped bass 

No swim speed studies located in literature. 

Gizzard shad juv 

juv 

25-50 mm 

N/A 

0.75 

2.8** 

 Not available 

max water velocity with HSI = 0.1; Williamson and Nelson 1985. 

 adult 250-350mm 

TL 

8.0* measured water velocity at ConoWest Lift-does not exclude adults 

Largemouth bass juv 150mm 0.79 @ 10C Beamish 1970 in Carlander 1977 

 150mm 1.57 @ 30C 

juv 250 mm 1.51 @ 10C 

 250mm 2.07 @30C 

 juv 75-85mm 1.21-1.34 Dahlberg et al. 1968 in Carlander 1977 

juv 52-64mm TL 0.50 @ 30C 1.63 Hocutt 1973; at 30C;--critical speed was max of tests from 15-35Cjuv 52-64mm TL 8.08L/sec Hocutt 1973; at 30C; same study--relative swim speed. juv 93-128mm 1.60 (see comments) U-crit 2 min = 3.5-3.8 BL/s; 15-19C; Kolok 1991 

 " 0.92 (see comments) U-crit 2 min = 2.2 BL/s; 5C; Kolok 1991 

 juv 52-64 mm 1.64 Farlinger and Beamish 1977 (cited in Beamish 1978); critical @ 2

juv 102 mm 1.50 Farlinger and Beamish 1977 (cited in Beamish 1978); critical @ 2juv 100 mm 1.15 Otto and Rice 1974 (cited in Beamish 1978); critical @ 10C 

fry 20-22mm 0.78-1.02 Larimore and Deuver 1968 (cited in Beamish 1978); prolonged @

juv 57mm 1.01 Larimore and Deuver 1968 (cited in Beamish 1978); prolonged @

lg juv 150-270 mm 1.80-2.17 Beamish 1970 (cited in Beamish 1978); prolonged at 10-30C. 

Smallmouth bass fry 20-25mm ≤0.89 Larimore and Deuver (1968) cited in Carlander 1977 & Houde 196

fry 14mm 13-19L/sec relative prolonged speed; Larimore and Deuver (1968) fry 14mm 0.60-0.87 range of prolonged speed; Larimore and Deuver (1968) 

juv 91-93mm 1.3-1.8 Critical swim speed, 2-min U-crit @ 13-23C range; Webb 1998. 

adult 262-378mmTL 1.6-3.9 Critical swim speed, U-crit-10 min @ 15-20C; Bunt et al. 1999. 

Spotted bass 

No swim speed studies located in literature. 
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Table 3-1. (Continued) 

SWIM SPEED-feet per second-ft/s 

Species

Life 

Stage Fish Size

Max. 

Sustained 

Prolonged or 

Critical 

Burst or 

Startle Literature Source-Comments-Clarifica

White bass adult 313mm TL 3.94 critical swim speed; U-crit-10 min; Tunink 1975; Schmulbach et a

et al. 2004. 

Walleye fry 12mm TL 0.16 18.3C; Houde 1969 

fry 20mm TL 0.25 13C; Houde 1969 

juv 80mm FL 1.24 Jones et al. 1974; critical swim speed @18-20C for 10-min 

lg. juv 317mm FL 11.0* Haro et al. 2004; @ 10.3C; able to enter fishway at this V (max tes

adult 380mm FL 2.74 Jones et al. 1974; critical swim speed @ 18-20C for 10-min 

juv 160mm FL 6.02 Fast-start or startle speed; calc. from formula in Peake et al. 2000. 

adult 350mm FL 7.20 Fast-start or startle speed; calc. from formula in Peake et al. 2000. adult 570mm FL 8.57 Fast-start or startle speed; calc. from formula in Peake et al. 2000. 

Alewife juv 2.5-3 in ~3.0 est. from Bell 1991; dart speed maintained for 7.5 sec; 

adult 250mm TL 11.5-16.4 range of burst swim speed in fishway; Dow 1962 cited in Beamish adult 235mm FL 11.2* Haro et al. 2004; @ 11.2C; able eto enter fishway at this V (max te

Herring (spp. ?) fry 0.8 in 1.0 est. from Bell 1991; dart speed maintained for 7.5 sec; 

adult 6-11 in ~5.0 ~6.7 est. from Bell 1991; dart speed maintained for 7.5 sec; 

Bluegill juv 25-40 mm FL 0.3-0.75 Schuler 1968; S/max = minimal swim speed in natural environmen

juv 39-44 mm FL 0.48-0.52 King 1969; S/max = minimal swim speed in natural environment; juv 51-54 mm 0.92 tested at 21C; Beamish 1978 

adult 203 mm TL 1.0 Deng et al. 2004 

adult unknown 0.98 Drucker and Lauder 1999 

 adult 100-150 mm 

TL 

1.22 Critical swim speed for 10-min; Gardner et al. 2006 

adult 153 mm TL 4.3 Webb 1978; final velocity measured after 9-sec burst over short di

Black crappie No swim speed studies located in literature. Black crappie juv 78 mm TL 0.5L/sec*** Assumed foraging swim speed, slower than sustained (Chick and VWhite crappie juv 55-100 mm 

FL 

0.50-0.75 S/max speed likely minimal sustained; 70-83F; Schuler 1968. 

juv 75-81 mm FL 0.54-0.61 S/max speed likely minimal sustained; 76-79F; King 1969. juv 77 mm SL 0.52 U-crit 60 min @ 25C; Smiley and Parsons 1997. juv 77 mm SL 0.18 U-crit 60 min @ 5C; Smiley and Parsons 1997. 

* Values cited represent measured current velocities (V) that fish were able to negotiate at a fishway entrance. ** Estimated from HSI curve in source literature. ***Assumed swim speed, not from laboratory test. 
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recognition of the role of fish size in swim performance, much information on burst swim speed may 

also be expressed as fish body lengths/sec (L/sec), termed “relative burst speed”. Smaller sized fish 

typically have a higher relative swim speed (more body lengths per second) than larger fish, even 

though the absolute swim speed of larger fish is faster. 

The data listed in Table 3-1 include studies specifically designed to measure one or more component 

of swim speed or performance, as well as other studies, typically more recent, that measure swim 

speed in relation to one or more variables, such as temperature changes, dissolved oxygen levels, etc. 

Where a temperature range or specific test temperature is provided, these are indicated. For others 

with a range provided, the maximum swim speed attained was listed along with the appropriate 

temperature. Where other conditions were tested, such as physically-conditioned fish versus nonconditioned fish, the data from non-conditioned fish were used as they best represent wild fish 

(Young and Cech 1993). Few studies were noted that tested fish with an objective of developing a 

water intake design, or tested vs intake design criteria (e.g., Tatham 1970; Hocutt 1973). In general, 

the comments or clarifications provided in Table 3-1 identify any information deemed useful to assist 

interpretation of the test result. 

For several species in Table 3-1, a listed burst swim speed was based upon successful upstream 

passage through a maximum water velocity at an actual or simulated fishway entrance, without an 

accompanying estimate of the actual swim speed attained (e.g, data for three species from Haro et al. 

2004; adult gizzard shad data). We interpreted these data to represent a minimum estimate of burst 

swim speed for the species considered. 

3.1.1 Striped bass 

Burst swim speed estimated for juvenile striped bass ranged from 2.0 to 5.0 ft/s, depending on fish 

length (Table 3-1). Fingerling striped bass stocked by VDGIF in Claytor Lake in June typically 

measure 25-50-mm TL (average about 41 mm), or 1 to 2-inches (Rash 2003; Copeland 2005). Thus, 

the burst swim speed shortly after stocking would approximate 2.0 ft/s, based upon data provided in 

Bell (1991). As the stocked juveniles grew to 5 in TL during their first year, estimated burst swim 

speed would increase to 5.0 ft/s. 

No estimates were found of actual burst swim speed for adult striped bass. However, Haro et al. 

(2004) tested the ability of comparatively small adult striped bass (mean FL = 554 mm, appropriate 

for an adult male striped bass) to enter a simulated fishway and pass upstream (the test flume is well 

described) over a range of current velocities. The maximum current velocity tested in the flume was 

14.9 ft/s. We interpreted that this value represents a minimum burst swim speed for adult striped bass, 

since test fish were able to penetrate 5 to 6-m into the test flume. 

3.1.2 White bass x striped bass hybrids 

Hybrid striped bass are stocked later in the season and at a larger size than striped bass, typically in 

late summer or early fall at approximately 3 in TL or longer (Rash 2003; Copeland 2005). Thorough 

searching revealed no available swim performance data for hybrid striped bass in the published 

literature. Given their comparability in habits with juvenile striped bass (Rash 2003), plus 

acknowledged greater hardiness and fighting ability as adults (Gleason 1982) relative to striped bass, 

their swimming ability should approach or be comparable to that of striped bass. Therefore, as 

stocked 3-in fingerlings, burst swim speed is likely between 2.0 to 5.0 ft/s, based on data in Bell 
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(1991). Similarly, an adult hybrid striped bass measuring 554 mm FL, as for striped bass cited in 

Haro et al. (2004) above, may be able to achieve a burst swim speed near 14.9 ft/s. This estimated 

swim speed for adult striped bass, however, is substantially higher than the burst swim speed 

estimated for adult white bass (7.9 ft/s), typically the male parent in the cross (see Section 3.7 below). 

As a result, a reasonable approximation of adult burst swim speed for hybrid striped bass would be 

the mid-point of the two estimates, or approximately 11.4 ft/s. 

An estimated swim speed near 11 ft/s for larger striped bass hybrids also appears reasonable based on 

numerous captures of a wide size range of yearling and older hybrid striped bass in a Maryland 

fishway (see Section 3.3 below). Water velocities at the fishway entrance are typically maintained 

near 8 ft/s to attract adult alosids. 

3.1.3 Gizzard shad 

We located no estimates of burst swim speed for either juvenile or adult gizzard shad. However, 

gizzard shad represent the most common species caught in a fishway located at Conowingo Dam on 

the Susquehanna River in Maryland. Fishway entrance current velocities have been measured 

historically to assist in capture of American shad, the primary target species. Measured current 

velocities of 8 ft/s represented no barrier to adult gizzard shad (estimated TL = 250-350mm) passage 

into the fishway entrance. We interpreted that this value represents a minimum burst swim speed for 

adult gizzard shad. A burst swim speed estimate for juvenile gizzard shad would likely be less than 8 

ft/s, based upon information in Table 3-1 and trends for other species actually tested. 

Two behavioral factors related to gizzard shad must also be acknowledged. First, gizzard shad are a 

schooling species. Schooling behavior confers enhanced survival (through presumably better 

swimming ability) as opposed to swimming as individuals (Boyd and Parsons 1998). Because of this 

schooling behavior, gizzard shad are prone to entrainment in large numbers. Second, gizzard shad are 

affected by low water temperatures (Williamson and Nelson 1985). During cold winters gizzard shad 

become increasingly moribund as water temperatures decline below 14°C (56°F), and die-offs of 

juveniles and adults occur at or below 3.3°C (38°F). Thus, the swimming ability of either life stage, 

and the ability to avoid entrainment, may be compromised during colder winters. 

3.1.4 Largemouth bass 

Although a common test animal in swim speed studies, we located no estimates of burst swim speed 

for either life stage of largemouth bass, perhaps because largemouth bass are not typically thought of 

as riverine nor a common user of fishways, often a stimulus for burst or sprint swim speed testing. 

The study by Hocutt (1973) tested juvenile largemouth bass swim speed for a proposed water intake 

on a reservoir. A range of studies cited in Table 3-1 identified critical swim speed for small juvenile 

largemouth bass (52-102 mm) of approximately 1.01-1.64 ft/s, within a temperature range of 15-

30°C. Prolonged swim speeds of large juveniles to perhaps small adults (150-270 mm) were faster, 

within the range of 1.80-2.17 ft/s. These speeds are faster than typical water intake design criteria 

used on reservoirs or rivers where intakes are usually oriented parallel to flow. 

Burst swim speed for juveniles would be faster than either of these estimated for prolonged or critical 

swim speed (above). Bell (1991) estimated that prolonged (= sustained in his terminology) swim 

speed was 50 % to 70 % of dart (burst) speed. Applying Bell’s “50% criteria”, an estimate of burst 

swim speed for small (52-102 mm) and large juvenile (150-270 mm) largemouth bass would be from 
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3.2 to 4.3 ft/s. Burst swim speed for adult (e.g., ≥ 305 mm) largemouth bass would be expected to be 

faster than for the larger juveniles. 

3.1.5 Smallmouth bass 

No studies of burst swim speed for smallmouth bass were located. Several studies that developed 

estimates of prolonged swim speed were identified and reported in Table 3-1. The maximum 

prolonged swim speed for juvenile smallmouth bass up to 93 mm long was 1.8 ft/s. A maximum 

critical swim speed (subset of prolonged swim speed) estimated for adult smallmouth bass up to 378-

mm TL was 3.9 ft/s. Again using the “50% criteria” from Bell (1991), a maximum estimate of burst 

swim speed for juvenile smallmouth bass is 3.6 ft/s, and 7.8 ft/s for adult smallmouth bass. 

3.1.6 Spotted bass 

No estimates of swim speed for spotted bass were located in the fisheries literature. Spotted bass prey 

preferences and diets are similar to smallmouth bass, but spotted bass habitat preferences are 

considered intermediate between their congeners (Jenkins and Burkhead 1993). It is reasonable to 

assume that swim speeds may also be intermediate between those estimated for largemouth and 

smallmouth bass. 

A minimal estimate of burst swim speed for juvenile largemouth bass is 3.2 ft/s, and approximately 

3.6 ft/s for juvenile smallmouth bass. Therefore, an intermediate estimate of burst swim speed for 

juvenile spotted bass would be approximately 3.5 ft/s. 

A minimal estimate of burst swim speed for small adult largemouth bass is 4.3 ft/s. Burst swim speed 

for adult smallmouth bass was estimated to be 7.8 ft/s. A reasonable estimate of burst swim speed for 

adult spotted bass would be approximately 6 ft/s, the midpoint of swim speeds estimated for the 

congeners. 

3.1.7 White bass 

No studies of burst swim speed for white bass were located. One estimate of the critical swim speed 

for adult (313 mm TL) white bass was 3.94 ft/s (Table 3-1), in reference to upstream passage of white 

bass through Mississippi River Corps of Engineers dams (Wilcox et al. 2004). Using the “50% 

criteria” from Bell (1991), an estimate of burst swim speed for adult white bass would be 

approximately 7.9 ft/s. The burst swim speed for juvenile white bass would likely be less than 7.9 ft/s 

due to their smaller size. 

3.1.8 Walleye 

Walleye swim speed information was comparatively abundant for walleye sizes ranging from larval 

(12-20 mm TL) to large adults (570 mm FL). However, burst swim speed data or estimates were 

available only for juveniles and adults larger than 160-mm FL (Table 3-1). 

Peake et al. (2004) tested the burst swim speed of walleye by startling (tail-touching) walleye in a 

holding tank and measuring their movement rate by video. The term “fast-start performance” was 

assumed synonymous with burst swim speed, and was found to increase linearly with fish size. The 

estimates of burst swim speed ranged from 6.02 ft/s for 160-mm FL walleye to 8.57 ft/s for 570-mm 

FL walleye, and were calculated from the regression equation “Speed (m/s) = 1.53 + 1.90*(fish FL in 

m)”. Tabulated data were converted to English units in Table 3-1. 
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Haro et al. (2004) tested walleye swimming ability to enter a simulated fishway entrance, and walleye 

were able to enter the test flume at current velocities up to 11.2 ft/s, the highest velocity tested for 

walleye. As for the striped bass (Section 3.1 above) tested in the same apparatus, 11.2 ft/s may be 

assumed to represent a minimum burst swim speed for large juvenile walleye that averaged 317-mm 

FL. 

Since loss of small juvenile walleye due to entrainment is often more of a concern than loss of adults, 

information from Bell (1991) may be applied to data for larval walleye (Houde 1969) to develop a 

rough estimate of burst swim capability for very small walleye approximating the fingerling size 

commonly stocked (typically 1-2 inches; Copeland 2005). Bell (1991) estimated that a fish’s cruising 

(= sustained) speed may be 15-20% of the dart (burst) swim speed. Houde (1969) reported a sustained 

swim speed of 0.25 ft/s for 20-mm TL walleye (Table 3-1). Thus, a conservative estimate of newlystocked walleye fingerling burst swim speed would be approximately 1.25 ft/s. Similarly, a burst 

swim speed of approximately 2.5 ft/s may be estimated for somewhat larger juveniles of 80-mm FL, 

based on the 10-min critical swim speed estimate of 1.24 ft/s (Table 3-1) reported by Jones et al. 

(1974) and application of the Bell (1991) “50% criteria”. 

3.1.9 Alewife 

Burst swim speeds for juvenile and adult alewife are reported in Table 3-1. The burst swim speed for 

juvenile alewife (2.5-3 inch; 64-76-mm) was approximately 3 ft/s. Two comparable estimates of burst 

swim speed were available for adult alewife (235-mm FL; 250-mm TL), both generated in studies of 

alewife upstream passage in fishways. Dow (1962) estimated a range of burst swim speeds in a 

fishway of 11.5 to 16.4 ft/s. Haro et al. (2004) tested adult alewife passage in a test flume that 

simulated a fishway entrance. The maximum water velocity tested at the flume entrance for 

successful ascent of adult alewife was 11.2 ft/s, which may represent a minimum estimate of burst 

swim speed. 

The burst swim speed estimates derived from Dow (1962) and Haro et al. (2004) were based on 

typical lengths of adult anadromous alewife. However, adults in land-locked populations such as in 

Claytor Lake are usually smaller. Further, in Claytor Lake the bulk of alewives are Age-0 or Age-1 

fish. Mean TL of alewife at the end of the first growing season may range from 130-160 mm TL, but 

late-spawning cohorts can be much smaller (Nigro and Ney 1982). Thus, for the bulk of alewives in 

Claytor Lake, the pertinent swim speed would probably be somewhat less than 11.2 ft/s. Additionally, 

landlocked alewife are especially susceptible to loss of swimming ability in cold water, so seasonal 

effects (further loss of swim speed and lethargy in winter) must also be considered. 

3.1.10 Bluegill 

Swim speed studies of both juvenile and adult bluegill were located. Bluegills are not considered 

strong swimmers, although tested juveniles oriented well to current (Schuler 1968). Bluegill body 

morphology is better suited for maneuverability than for fast swim speed (Deng et al. 2004). 

Sustained swim speeds of 0.3 to 0.75 ft/s were reported for young of year bluegill at typical summer 

water temperatures by Schuler (1968) and King (1969). Adult sustained swim speed was faster, about 

1.0 ft/s (Drucker and Lauder 1999; Deng et al. 2004). Prolonged swim speed of young of year 

bluegill at 21°C was 0.92 ft/s (Beamish 1978). Critical swim speed of bluegill tested for 10 min, 

considered sufficient for culvert passage, was 1.22 ft/s, although fish size was not specified (Gardner 

et al. 2006). The burst swim speed of adult bluegill was estimated at 4.3 ft/s, attained over a 9-sec test 
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period using high speed photography (Webb 1978). However, this speed was reported as a final 

velocity calculated from an acceleration rate, and may represent a faster speed than might be 

estimated by more conventional test methods. 

3.1.11 Black crappie 

No swim speed studies for black crappie were located. However, the swim speed studies of closely 

related white crappie reviewed below suggested that black crappie may represent the poorest 

swimmers of the species considered herein. 

Juvenile white crappie 55 to 100 mm FL were able to swim at between 0.50 to 0.75 ft/s in tests at 

typical summer water temperatures (Schuler 1968; King 1969). However, their behavior in the test 

apparatus suggested poor orientation to current, as many fish tended to drift passively even at low 

water velocities. Investigators also noted that the swim performance of 80-mm long white crappie 

was similar to that of 40-mm long bluegill. 

The critical swim speed of juvenile white crappie was estimated at 0.52 ft/s at 25°C, but was 

substantially lower (0.18 ft/s) when tested at 5°C, a typical winter water temperature in Virginia 

(Smiley and Parsons 1997). No studies of burst swim speed for white crappie were located. Based on 

the conservative application of the “50% criteria” from Bell (1991), an estimate of white crappie burst 

swim speed would be 1.0 to 1.5 ft/s. Based on white crappie as an appropriate surrogate, it is likely 

black crappie swim speeds would be similar. 

3.2 FIELD STUDY OF INTAKE VELOCITY

Water current measurements were taken in front of the Claytor Project intakes on April 14, 2008. The 

intake current data were taken at two flow rates and compared to existing engineering calculations of 

intake velocity taken from original project drawings. These data were then compared to the swim 

speed information developed in Section 3.1. 

3.2.1 Field Methods 

A boat-mounted 300 kHz Acoustic Doppler Current Profiler (ADCP) connected to a laptop PC was 

used to acquire water current measurements in both horizontal and vertical dimension. The ADCP 

data system was operated in concert with a differential global positioning system (GPS) that fed data 

to the ADCP and a navigation software package on a separate PC. The navigation package provided 

accurate position updates each second. All data systems were clock-synchronized to enable accurate 

X-Y positioning during data processing. 

Data were collected for five transect types at two flow conditions. A discharge of 10,000 cfs 

represented all four units at maximum output. The 2,000 cfs condition represented one unit at MEP 

flow. The five transect types included: 

 Fixed station vertical profiles in front of each intake; position maintained for 

approximately 4 minutes. 

 Tangential transects run parallel to the intake structure face. Four transects were run per 

flow, each further away from the intakes. 

 Normal transects run perpendicular to each intake, starting near the intake. A pair of 

transects was run for each intake (each intake has two bays). 
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 Transects run parallel to the log boom. 

 Two far-field transects, approximately 0.5-mile and one mile uplake from the intakes. 

A log boom running diagonally uplake from Unit 4 that intercepts surface debris interfered with boat 

movements during tangential and normal transect runs. Figures in the accompanying full report show 

the location of the log boom. Transects were completed by positioning the boat outside the log boom 

to continue data collection. The breaks in positional data are also shown on report figures. 

Approach velocity data could not be obtained closer than approximately 40 feet from the intake wall. 

The ADCP transducers are angled 20° from vertical and signals propagate downward as a coneshape. The 40-foot distance permitted data acquisition without interference by acoustic reflections off 

the dam face. 

Additional details of the ADCP and GPS data systems are provided in the accompanying field study 

report prepared by Ocean Data Technologies, Inc.. The full report describes data processing steps, 

and presents all the data in tabular or graphical detail. The study report also includes all electronic 

data files on compact disk. Study results are summarized below in tabular fashion for the fixed station 

profiles, and by representative graphics for both types of near-dam transects. These transects 

represent the zones of influence for fish entrainment. Results for the log boom and uplake transects 

are provided in the separate field study report. 

3.2.2 Results 

All fixed-position profiles were taken at 38 to 75 feet in front of the intakes. The maximum velocities 

measured at the 10,000 cfs flow condition were 0.60 ft/s to 0.68 ft/s in the upper half of the intake in 

front of Unit 3 (Table 3-2). Directional data for the fixed profiles in front of Units 1-3 also depict 

flows heading directly toward the intakes (i.e., at about 45° heading). Current velocities for the single 

unit MEP flow of 2,000 cfs provided by Unit 4 were substantially less, but also occurred at depths 

nearest the upper intake elevation (Table 3-3). Current directionality among all profiles at 2,000 cfs 

was decidedly weaker and inconsistent. Recall that the calculated velocity at the intake face was 1.5 

ft/s (Section 2.2). Flow acceleration toward the protective bar racks and potential effects on fish thus 

occurs mainly within a comparatively short distance in front of the Claytor project intakes. 

The results of the tangential and normal transects agreed well with the fixed profile data. Each figure 

depicts current velocity and flow direction by color code with an accompanying color legend adjacent 

to the right axis. Figure 3-1 shows the parallel transect closest to the intakes at the 10,000 cfs flow. 

The maximum velocity was less than 1.5 ft/s, most of the transect contained velocities less than 1.0 

ft/s, and the highest velocity component occurred in front of Unit 3. The current velocities further 

upstream at 10,000 cfs, and along all tangential transects at 2,000 cfs were substantially less. 

Similarly, for the normal transects the current velocity was highest at the portion of each transect 

nearest the intake wall. Figure 3-2 shows the highest velocities at 10,000 cfs in front of Unit 2, with 

velocity decreasing progressively with distance up-lake, as you would expect. In the vertical aspect, 

both sets of transect profiles showed that current velocities were highest in the upper portion of the 

intake profile, as also noted for fixed station data. Flow direction at 10,000 cfs was strongest in the 

North-East quadrant (toward the intakes). The normal transects also show flow directionality 

weakening with distance up-lake from the intake. 
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Table 3-2. Speed and direction values for each fixed station profile. CL = approx. centerline. 

10,000 cfs Flow Rate

Location 

ID Intake 1: F110 Intake 2: F210 Intake 3: F310 Intake 4: F410 

Duration 4.21 min 3.92 min 4.45 min 4.98 min 

Depth (feet) 

Speed 

ft/sec 

Direct 

(deg) 

Speed 

ft/sec 

Direct 

(deg) 

Speed 

ft/sec 

Direct 

(deg) 

Speed 

ft/sec 

Direct 

(deg) 

10.1 0.33 28.6 0.44 54.0 0.53 70.7 0.42 100.0 

16.6 0.35 34.9 0.47 50.0 0.60 56.6 0.46 88.7 

23.2 0.37 38.3 0.46 54.3 0.68 56.4 0.41 85.9 

29.7 0.40 38.9 0.46 47.2 0.65 43.4 0.38 78.9 

36.3 0.39 36.2 0.52 51.4 0.60 45.0 0.42 84.3 

42.9-CL 0.37 36.3 0.37 59.9 0.48 63.8 0.41 94.6 

49.4 0.27 44.0 0.42 62.9 0.43 70.7 0.31 109.4 

56.0 0.20 61.0 0.41 58.9 0.38 57.2 0.33 85.1 

62.5 0.20 54.0 0.23 63.5 0.20 77.0 0.17 119.9 

69.1 0.11 57.4 0.11 98.0 0.20 79.4 0.18 121.0 

75.7 0.12 81.4 0.18 100.9 0.28 82.4 0.16 114.2 

82.2 0.14 74.1 0.18 144.2 0.19 122.8 0.14 206.8 

88.8 0.06 241.2 0.29 134.9 0.19 107.4 0.10 198.8 

95.3 0.04 259.3 0.32 101.7 0.43 105.3 0.25 245.9 

Table 3-3. Speed and direction values for each fixed station profile. CL = approx. centerline. 

2,000 cfs Flow Rate

Location 

ID Intake 1: F12 Intake 2: F22 Intake 3: F32 Intake 4: F42 

Duration 3.68 min 3.68 min 3.68 min 4.27 min 

Depth (feet) 

Speed 

ft/sec 

Direct 

(deg) 

Speed 

ft/sec 

Direct 

(deg) 

Speed 

ft/sec 

Direct 

(deg) 

Speed 

ft/sec 

Direct 

(deg) 

10.1 0.08 55.3 0.11 45.2 0.06 45.8 0.20 98.4 

16.6 0.06 331.0 0.12 13.1 0.04 36.5 0.17 50.0 

23.2 0.16 322.9 0.09 336.1 0.05 57.6 0.08 18.3 

29.7 0.08 292.9 0.09 215.6 0.10 58.2 0.07 290.6 

36.3 0.04 228.8 0.03 31.6 0.07 20.4 0.05 101.3 

42.9-CL 0.07 323.3 0.03 124.3 0.09 356.9 0.11 21.2 

49.4 0.01 45.0 0.18 49.6 0.10 87.8 0.08 328.4 

56.0 0.05 306.0 0.11 50.5 0.22 131.2 0.07 236.6 

62.5 0.06 331.7 0.15 2.3 0.13 172.2 0.07 4.1 

69.1 0.07 202.8 0.10 169.3 0.16 138.8 0.02 293.1 

75.7 0.04 114.6 0.08 179.8 0.01 100.8 0.09 342.0 

82.2 0.09 202.3 0.05 117.3 0.12 90.2 0.08 334.9 

88.8 0.14 176.6 0.07 57.2 0.21 110.1 0.01 276.8 

95.3 0.09 179.5 0.15 101.2 0.23 85.2 0.07 27.8 
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Figure 3-1. (T110) Color-contour section for tangential line (parallel transect) approximately 40 feet 

off the intake wall for 10,000 cfs condition. Box outline = intake centerline 44 feet deep. 

Figure 3-2. (N2A10). Color-contour section for normal line (perpendicular transect) in front of Unit 

#2 for the 10,000 cfs condition. Distance refers to distance from the face of the intake 

wall. Intake centerline is 44 feet deep. 
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Figure 3-3. (T10-43) Synoptic velocity vectors 43 feet below the surface during the 10,000 

cfs condition. Intake bays are labeled U1, U2, etc. Scale arrow in lower left 

represents the length of a 1 ft/s vector. . ................................................................................ 

The tangential transect data were also used to generate synoptic velocity vectors (arrows) that depict 

regional flow fields in front of and near the intakes. The vectors point in the direction of the flow and 

are scaled to current speed (ft/s). Figure 3-3 shows the flow vectors 43 feet deep near the intake 

centerline at 10,000 cfs. Current flow generally follows a consistent path toward the intakes for Units 

1-3. However, flow toward Unit 4 runs parallel to the dam before bending sharply toward the intake. 

Similar vector direction and speed occurred at the 23-foot depth corresponding to the upper portion 

of the intakes, but were notably slower at 69 feet deep (see report). 

3.3 FIELD VELOCITIES VS FISH SWIMMING CAPABILITIES

Results of field velocity studies near Claytor Lake Dam described above combined with engineering 

calculations of at-rack intake velocity (Section 2.2) generally depict acceleration of the near-dam 

water mass from about 75 ft up-lake directly toward the intakes. Intake velocities appeared highest in 

the upper water column, from about the intake centerline (44 ft deep) to approximately 10 ft deep. In 

this reach, the water current increases from ≤ 0.5 ft/s to 1.5 ft/s. Velocity was notably less in deeper 

areas near the intakes. This summarization of intake velocities is shown with summarized fish swim 

speed information in Table 3-4. 

The review of fish swimming ability clearly identified the juvenile period as the life stage most 

vulnerable to entrainment. However, by mid-to-late summer, larger juveniles of most species are 
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capable of escaping the at-rack velocity of 1.5 ft/s. The exceptions would likely be limited to crappie 

and late-spawned bluegill. These species are primarily littoral zone residents, however, and therefore 

generally reside away from the intake area that is located more than 200 ft offshore. Larger juveniles 

and adults have the swimming ability to avoid intake flow velocities, even during full generation 

(10,000 cfs). 

Newly stocked striped bass and walleye (if stocked) at < 2 inches long are also vulnerable to intake 

velocities. Although stocked in off-channel areas such as coves, an early summer spate might displace 

stocked juveniles from typical rearing areas and transport numbers of young downstream toward the 

intake area, potentially leading to higher losses of stocked fish to the New River downstream of the 

dam. 

Swim performance for several species listed in Table 3-4 was poorer in colder water, as detailed in 

Table 3-1. For example, swim test results for white crappie at 5°C showed one-third the swimming 

ability compared to tests conducted at 25°C. Juvenile largemouth bass were also poorer swimmers in 

cold water. Other species such as alewife and gizzard shad become moribund or succumb at low 

water temperatures. In either instance, reduction or loss of swimming ability and the behavioral 

response necessary to avoid intake flows can lead to increased episodes of fish entrainment. 
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Table 3-4. Comparison of Claytor Lake intake velocity data and synthesis of fish swim speed 

information. 

Velocity Estimate Type Approach Velocity (ft/s) 

Engineering drawing-at rack 1.5 

ADCP fixed profile @ 10,000 cfs 0.60-0.68 

ADCP fixed profile @ 2,000 cfs ≤ 0.2 

ADCP tangential and normal profiles < 1.5 cfs 

Species Life Stage Size (in) Burst Swim Speed (ft/s) 

Striped bass Juv 2 - 5 2.0 - 5.0 

 Adult 21.8 14.9 

Hybrid striped bass Swim speed intermediate between striped bass and white bass 

Gizzard shad Juv N/A 

 Adult 8.0 

Largemouth bass Juv 2 - 4 3.2 

Juv 5.9 - 10.6 4.3 

 Adult N/A 

Smallmouth bass Juv 3.6 

 Adult 7.8 

Spotted bass Swim speed intermediate between largemouth bass and smallmouth bass 

White bass Juv N/A 

 Adult 7.9 

Walleye Juv ~1 1.25 

 Juv 3.1 2.5 

 Juv 6.3 6.02 

 Juv 12.5 11.0 

 Adult 22 8.57 

Alewife Juv 2.5 - 3 ~3.0 

 Adult 9.3 11.2 

Bluegill Juv 2 1.8 

Adult 4 - 6 2.4 

 Adult 6 4.3 

Crappie Juv ~3 ~1-2 

Original swim speed data shown in Table 3-1. Absent a fish size or size range, no specific test was conducted; estimates 

were derived as described in text. 
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4.0 COMPARATIVE ANALYSIS OF SIMILAR PROJECTS

Selected project data in Table 2-1 were compared to comparable project data available in the EPRI 

(1997) database to provide some perspective on the subsequent analyses herein, particularly the 

potential for entrainment. The EPRI (1997) analysis examined fish entrainment for 43 sites including 

turbines of both Francis and Kaplan/propeller configurations. The sites represented in the EPRI 

database are listed in Table 4-1. 

The Claytor Project is large compared to the 43 sites reviewed by EPRI. Based on plant capacity 

(8,000 cfs is the MEP combined flow for the four units at Claytor; see Table 2-1), only one site 

(Richard B. Russell) exceeded the plant capacity of the Claytor Hydro Project. Further, only one site 

approached the MEP plant flow capacity (Minetto). Similarly, the MEP flow for an individual turbine 

unit at Claytor Project (2,000 cfs) was exceeded by only three sampled units. Most (31) sampled units 

discharged less than 1,000 cfs. 

Trash rack spacing for the 43 projects examined by EPRI (1997) is also listed in Table 4-1. Most 

projects (all but four) had rack spacing narrower than the 4-inch spacing at the Claytor Project. Some 

sampled sites featured rack spacing as narrow as 1-inch. However, a subsequent examination of rack 

spacing and fish entrainment catch performed on EPRI (1997) data by Winchell et al. (2000) found 

that rack clear spacing had little effect on fish entrainment, particularly on the size of fish entrained 

(Table 4-2). 
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Table 4-1. Location, hydraulic capacity and trash rack spacing of 43 sites included in the 

EPRI database. 

Site Name State River 

Total 

Plant 

Capacity

(cfs) 

Average 

Capacity of 

Sampled Units 

(cfs) 

Clear 

Trash Rack

Spacing 

(in) 

Belding MI Flat 416 208 2 

Bond Falls MI W.B. Ontonagon 900 450 3 

Brule WI Brule 1,377 458 1.62 

Buzzard's Roost SC Saluda 3,930 1,310 3.625 

Caldron Falls WI Peshtigo 1,300 650 2 

Centralia WI Wisconsin 3,640 550 3.5 

Colton NY Raquette 1,503 450 2 

Crowley WI N.F. Flambeau 2,400 1,200 2.375 

E. J. West NY Sacandaga 5,400 2,450 4.5 

Feeder Dam NY Hudson 5,000 1,000 2.75 

Four Mile Dam MI Thunder Bay 1,500 500 2 

Gaston Shoals SC Broad 2,211 837 1.5 

Grand Rapids MI/WI Menominee 3,870 739 1.75 

Herrings NY Black 3,610 1,203 4.125 

High Falls NY Beaver 900 300 1.81 

Higley NY Raquette 2,045 682 3.63 

Hillman Dam MI Thunder Bay 270 270 3.25 

Hollidays Bridge SC Saluda 4,396 370 unknown 

Johnsonville NY Hoosic 1,288 644 2 

Kleber MI Black 400 200 3 

Lake Algonquin NY Sacandaga 750 750 1 

Luray VA S.F. Shenandoah 1,477 369 2.75 

Minetto NY Oswego 7,500 1,500 2.5 

Moshier NY Beaver 660 330 1.5 

Ninety-Nine Islands SC Broad 4,800 584 1.5 

Ninth Street Dam MI Thunder Bay 1,650 550 1 

Norway Point Dam MI Thunder Bay 1,775 575 1.69 

Potato Rapids WI Peshtigo 1,380 500 1.75 

Raymondville NY Raquette 1,640 1,640 2.25 

Richard B. Russell GA/SC Savannah 60,000 7,200 8 

Saluda SC Saluda 812 227 unknown 

Sandstone Rapids WI Peshtigo 1,300 650 1.75 

Schaghticoke NY Hoosic 1,640 410 2.125 

Shawano WI Wolf 850 850 5 

Sherman Island NY Hudson 6,600 1,650 3.125 

Thornapple WI Flambeau 1,400 700 1.69 

Tower MI Black 404 202 1 

Townsend Dam PA Beaver 4,400 2,200 5.5 

Twin Branch IA St. Joseph 3,200 600 3 

Warrensburg NY Schroon 1,350 1,350 unknown 

White Rapids MI/WI Menominee 3,994 1,225 2.5 

Wisconsin River Division WI Wisconsin 5,150 431 2.19 

Youghiogheny PA Youghiogheny 1,600 800 10 
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Table 4-2. Size composition of entrainment catch by bar rack spacing (after Winchell et al. 

2000). 

Average Composition (%) by Size Class (inches) Clear Spacing 

(inches) N 0 to 4 4 to 8 8 to 15 15 to 30 > 30 

Representative 

Units 

1 3 61.5 32.2 5.5 0.9 0.0 

1.5-1.8 10 64.8 27.1 7.5 0.6 0.0 

2.0-2.75 12 68.9 25.3 5.1 0.7 0.0 

3.0-10.0 14 80.0 15.7 3.9 0.3 0.0 All Claytor Units* 

All 39 71.3 22.9 5.3 0.5 0.0 

* Bar rack clear spacing = 4.0 inches. 
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5.0 ENTRAINMENT ASSESSMENT

5.1 CHARACTERISTICS AND BEHAVIOR OF SELECTED FISHES

In evaluating entrainment susceptibility and effects, the eleven target species (juvenile and adults of 

striped bass, hybrid striped bass, gizzard shad, largemouth bass, smallmouth bass, spotted bass, white 

bass, walleye, alewife, bluegill, and black crappie) were considered separately. Following are brief 

life history accounts for each of the species considered in this study, with emphasis on their 

distribution within Claytor Lake. 

5.1.1 Striped Bass 

Striped bass is a significant recreational species in Claytor Lake, accounting for approximately 10% 

of angler effort during 1998-1999, the most recent creel survey period (Copeland 2004). The 

population is maintained by stocking 1 to 2-inch fingerlings during June of each year. Stocking 

densities since 2001 have been about 13 to 17 fingerlings per acre. Fingerlings were stocked during 

2001 and 2002 in two or three coves throughout Claytor Lake, including coves in lower-, mid-, and 

up-lake areas (Rash 2003). 

Juvenile striped bass rapidly disperse from stocking sites, residing primarily in shallow littoral areas 

with open sand-bottom habitat (Van Den Avyle and Higginbotham 1979; Rash 2003). Stocked 

juvenile striped bass quickly become piscivorous at about 120 mm in mid-summer, growing fast 

enough to successfully exploit young-of-year (YOY) alewives. Rash (2003) was most successful 

capturing YOY striped bass at lower lake littoral areas, which also corresponded to lower-lake 

habitats favored by spawning alewife, particularly along the north shore downstream of Claytor Lake 

State Park (Nigro and Ney 1982). Striped bass young likely follow alewife movements from littoral 

spawning areas to more pelagic, off-shore areas later in fall as water temperatures cool. Yearling 

striped bass move back onshore in spring, again exploiting YOY alewives. It is likely juvenile striped 

bass remain in close proximity to favored alewife food sources until the thermal requirements of 

mature striped bass intervene during the hottest periods. 

The distribution of older striped bass in Claytor Lake is water temperature and/or food supply driven. 

Large striped bass actively seek the coolest water available when water temperatures become warmer 

than preferred (Cheek et al. 1985). Coutant (1985) defines suitable summer habitat for adult striped 

bass as having water temperatures between 18 and 25°C, and DO concentrations at least 2-3 mg/L. As 

a result, striped bass in Claytor Lake are distributed much more broadly during fall through spring, 

but tend to be restricted to the deeper reaches in the lower one-third of the lake in summer. The 

deeper reaches provide required cooler water temperatures that are unavailable in the shallower upper 

areas. Net uplake movements of adults occur in fall and spring, as large striped bass either leave 

thermal refugia as water temperatures cool or stage for spawning migrations to lake headwaters, 

respectively. 

Although adult striped bass occupy lower lake habitats at depths similar to powerhouse intakes, little 

evidence of transport out of Claytor Lake exists for the larger specimens. More likely, downstream 

movement out of Claytor Lake occurs during the period shortly after stocking when juveniles 

(fingerlings) are rapidly dispersing from the stocking locations. 
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5.1.2 Striped bass x white bass hybrids 

Hybrid striped bass fingerlings stocked during late summer maintain the fishery in Claytor Lake. 

Hybrids are larger (3 to 5 inches) than striped bass at the time of stocking, but due to the time of year 

are unable to exploit YOY alewives and gizzard shad that have grown too large to ingest. YOY 

hybrids feed primarily on young Lepomis when they became piscivorous at approximately 120 mm 

(Rash 2003). Hybrid juveniles preferred open, sandy littoral habitats, similar to young striped bass, 

with similar thermal niches (Rash 2003). Seasonally, YOY hybrids moved offshore in December, and 

back on-shore in March-April, similar to striped bass movements (and alewives). 

Adult hybrids exhibit the same general within-lake seasonal movement patterns as striped bass, but in 

a given reach may occupy slightly different areas either horizontally or vertically (Kilpatrick 2003). 

Vertical separation occurs in summer due to the warmer water temperature tolerances of hybrids 

which allow them to exist higher in the water column. Horizontal separation within a 700-m reach 

was noted as both groups staged prior to moving uplake for the spawning run. 

Hybrids were stocked due to the belief they were less prone than striped bass to emigrate 

downstream. Hybrids have become established in dam tailwaters, although little evidence exists to 

suggest when or at what size movement out of the lake occurs. One adult hybrid moved to dam 

tailwaters between February and April 2002, possibly exiting during a period of high inflow 

(Kilpatrick 2003). However, most hybrids probably exit as juveniles during their first year during 

post-stocking dispersal, based on prior experience with hybrids in a large hydroelectric reservoir 

(Normandeau Associates, in-file data). 

5.1.3. Gizzard shad 

The spatial distribution of gizzard shad in Claytor Lake generally overlaps that of alewives, the other 

clupeid forage species, due to generally similar mesotrophic characteristics throughout the lake 

(Bonds 2000). Gizzard shad are primarily residents of shallow, littoral habitats. Standing stock 

estimates in 1997, ten years after they became established, revealed that gizzard shad comprised 35% 

of littoral fish biomass based in cove rotenone samples (Small 2002). However, overall abundance is 

regarded as low compared to more eutrophic reservoirs. 

Gizzard shad in Claytor Lake spawn in the spring, beginning in mid-May around the same time as 

alewives (Small 2002). Peak larval densities were attained in late June, and larval captures ceased in 

early August. YOY gizzard shad appear in fish diets at about 20 mm in mid to late summer; Age 1 

shad are eaten only in spring before the new cohort is available. First-year growth in Claytor Lake is 

rapid, and YOY reach a mean length of 155 mm TL at Age 1, larger than Age 1 gizzard shad in other 

similar reservoirs (Bonds 2000). The rapid growth of young-of-year gizzard shad in Claytor Lake 

limits their usefulness as prey for piscivorous young of predators, and for the most part their 

contribution as forage to predator populations other than for the largest adults is as Age-0 fish, as 

commonly observed elsewhere (e.g., Ney et al. 1988). Young gizzard shad provide the main forage 

for striped bass and hybrid striped bass in late summer and fall, and represent a secondary forage 

species (after alewives) for walleye (Bonds 2000). 

Gizzard shad apparently are routinely transported out of Claytor Lake to the New River and reservoirs 

downstream (Bonds 2000). Gizzard shad will succumb or become moribund at prolonged water 

temperatures below about 3°C (37°F) (see review in Williamson and Nelson 1985). Young gizzard 

shad typically pass out of temperate reservoirs during fall and early winter as their lower temperature 
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threshold is approached and swimming ability is reduced or lost. The loss of swimming ability creates 

their susceptibility to entrainment, and as a result fall/winter gizzard shad entrainment peaks are 

typical in reservoirs where they are abundant (FERC 1995). 

5.1.4 Largemouth bass 

Largemouth bass currently comprise about 30% of the three black bass species in Claytor Lake as 

determined by electrofishing (Copeland 2004). However, the angler catch of largemouth bass was 

equal to the combined catch of the other two black bass species in the most recent creel survey 

(Copeland 2004). Largemouth bass electrofishing catch rates increased during 1992 to 1998 in 

Claytor Lake. Based on VDGIF electrofishing samples over the same period, largemouth bass spatial 

population densities are comparatively even among upper, mid, and lower lake reaches. Abundance is 

highest in off-channel coves, including Peak Creek, the major tributary arm. Largemouth bass growth 

is good and condition is excellent (Copeland 1999). Bluegill and crayfish dominated the diet of 

largemouth bass in all seasons, but alewives and gizzard shad can be important seasonal diet 

components (Bonds 2000). Reliance on bluegill identifies largemouth bass as mainly littoral zone 

inhabitants. 

Largemouth bass spawn in spring and build nests in shallow, littoral zone habitats typically associated 

with cover objects. Adults guard the young after hatching, and young bass remain in shallow, 

protected habitats such as coves and flooded tributary mouths following cessation of parental care. 

Adults typically establish home ranges during the summer into fall. Largemouth bass are generally 

considered inactive during winter (Cooke et al. 2003). Strong orientation to cover and preference for 

shallower, off-channel habitats generally limits largemouth bass exposure to entrainment through 

water intakes. 

5.1.5 Smallmouth bass 

Smallmouth bass are most abundant in lower and mid-lake areas, which afford an abundance of 

steeper, rocky shoreline habitats (Copeland 1999; 2004). Throughout most of the 1990s overall 

smallmouth bass abundance (electrofishing CPUE) was about equal to that of largemouth bass. The 

representation of smallmouth bass in the 1998-1999 sport fishing survey was 38% of the total black 

bass catch (Copeland 1999). Crayfish and bluegill dominated the smallmouth bass diet (Bonds 2000). 

Smallmouth bass spawn in spring and build nests associated with littoral zone cover, and guard their 

young after hatching. Young bass remain in shallow, protected habitats following cessation of 

parental care. After spawning, adult smallmouth bass may move about within a variable-sized home 

range in summer. Smallmouth bass may move from littoral areas in late fall to winter aggregations 

associated with cover in deep water (Langhurst and Schoenike 1990). Although more abundant in 

downlake areas of Claytor Lake, the numerous protected coves combined with smallmouth bass 

preferences for shallow littoral habitats would tend to isolate most young smallmouth bass, typically 

the life stage most vulnerable to entrainment, from the submerged, offshore-sited intake structures 

located in the lower lake. 

5.1.6 Spotted bass 

Spotted bass are the most abundant of the black bass species in Claytor Lake based on electrofishing 

CPUE (Copeland 1999). Spatially, spotted bass abundance is highest in the upper portion of the lake. 

Its habitat requirements, intermediate between those of largemouth and smallmouth bass (Miller 
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1975; Jenkins and Burkhead 1993), and higher tolerance for turbidity (Trautman 1981, in Jenkins and 

Burkhead 1993) conform to the more riverine character and higher turbidity of upper Claytor Lake. 

Seasonal movements to deeper lake areas (offshore) in winter may occur based on accounts in Miller 

(1975). 

Spotted bass formed 12% of the black bass catch during the 1998-1999 creel survey (Copeland 1999). 

Adult dietary components strongly favored crayfish with some bluegill, similar to smallmouth bass 

(Bonds 2000). 

Spotted bass construct nests on firm bottom at depths to 20 ft when water temperatures near 60°F 

(Jenkins and Burkhead 1993). A wide variety of firm bottom types are acceptable, but nearby cover is 

also important (Miller 1975; Vogele 1975). Young aggregate in schools while guarded by the male, 

then gradually disperse at about 30 mm (Vogele 1975). The occurrence of most spotted bass in uplake areas, tight schooling aided by parental care, and strong association with cover may make the 

species less prone to entrainment at the most vulnerable juvenile stage. 

5.1.7 White bass 

White bass are highly fecund, mobile, pelagic predators that move to reservoir headwaters or tributary 

rivers to spawn in spring. Claytor Lake white bass abundance is considered low (Copeland 2004), 

possibly due to competition from hybrid striped bass or predation on larvae by alewives (Kohler 

1980, cited in Bauer 2002). In Claytor Lake spawning success and dominant white bass year classes 

occur during Aprils with high run-off (DiCenzo and Duval 2002). Poor or missing year classes result 

from springs with low reservoir inflow. Spawning occurs on the open-water surface and the eggs are 

demersal and adhere to the bottom. Young prefer shallow water over harder bottom, but remain in 

littoral zones only during early life stages (Horrall 1962, in Becker 1983). When in littoral habitat the 

young prefer sandy substrates, similar to striped bass and hybrid striped bass. 

Larval white bass utilize a diurnal vertical migration to slow downstream transport from high-current 

spawning areas (Starnes et al. 1983). This mechanism may effectively permit young white bass to 

grow to a larger size with higher swim performance capability before reaching Claytor Dam intakes, 

thereby reducing susceptibility to entrainment during the most vulnerable life stage. 

Following spawning in the upper reaches of Claytor Lake, most adults would likely move 

downstream to the main body of the reservoir. The summer-fall spatial distribution of larger white 

bass would likely mimic prey movements. White bass are schooling, aggressive pelagic predators that 

favor clupeid prey where they co-exist. White bass would likely follow schools of YOY alewives and 

gizzard shad, the dominant pelagic prey in Claytor Lake. White bass were heavy consumers of 

alewives prior to gizzard shad introduction (Boaze and Lackey 1974). During summer, white bass 

were found primarily within the top 6 m (20 ft) of the water column (Tibbles 1956, in Becker 1983). 

During the rest of the year they were found in deeper waters. White bass remain active during winter 

(Cooke et al. 2003). 

Larger white bass respond to seasonal prey movements, and since they remain active during winter 

could be susceptible to fall/winter entrainment as discussed below for walleye. White bass will follow 

clupeid schools (alewives in this case) throughout the upper 14 m (46 ft) of the water column (Boaze 

1972). 
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5.1.8 Walleye 

Claytor Lake walleye have received substantial management focus based on genetic characteristics in 

recent years. Prior to research recommendations to enhance the riverine walleye stock (Palmer 1999; 

Palmer et al. 2005), which may be native, walleye fry and fingerlings from largely lake sources were 

heavily stocked periodically since impoundment (Rosebery 1951; Copeland 1999), with the goal of 

establishing and maintaining a pelagic lake sport fishery. However, the principle sport fishery for 

walleye occurs in the New River upstream of Claytor Lake in spring during the spawning run. The 

lake sport fishery is negligible, representing less than 1% of total effort (Copeland 1999), likely due 

to the preference of adult walleye for deep, off-shore waters most of the year (Palmer 1999). 

Adult walleye that mostly reside in the lower two-thirds of Claytor Lake move upstream during late 

February into early May to spawn in lake headwaters near Allisonia (Palmer 1999). Adults then 

return to pre-spawn home ranges in the lower lake that typically extend over 13 linear kilometers in 

size. The adults are considered nomadic within the home range, moving continually, likely in 

response to movements of alewife schools (Palmer et al. 2005). Alewife represents the preferred prey 

of walleye (Boaze and Lackey 1974; Bonds 2000). 

Young walleye spawned in the New River likely drift downstream to rear in Claytor Lake. Young in 

other lakes are pelagic until they grow to slightly longer than 1 inch, then return to inshore rearing 

areas (Becker 1983). Dispersal of naturally produced young walleye (≤ 2 inches) to downstream 

tailwaters occurs at many reservoirs (FERC 1995). This is about the same size of stocked walleye. 

Movement of larger juvenile walleye out of reservoirs is also common in late fall and winter, often 

accompanied by increased inflows and shorter flushing times (FERC 1995; Jernejcic 1986). Larger 

walleye may also follow stressed prey such as cold-stressed clupeids to deeper reservoir areas thereby 

increasing susceptibility to entrainment into submerged water intakes (RMC 1992). 

5.1.9 Alewife 

Landlocked alewife were introduced during the 1960s, and along with introduced gizzard shad, 

comprise the main forage base for pelagic predators in Claytor Lake. Alewife spawn principally in 

littoral, lower-lake areas adjacent to their preferred, pelagic habitats (Nigro and Ney 1982). Alewife 

exhibit a protracted spawning period that extends approximately 13 weeks, beginning in early May 

and lasting until early August. Larvae consume zooplankton but also prey on larvae of other fishes 

(Kohler et al. 1986). Nigro and Ney (1982) documented a daily growth increment of 0.68-mm in 

Claytor Lake. The long growing season resulted in young attaining 155 mm at Age 1, a length beyond 

the capability of all but the largest predators to ingest. 

Alewife seasonal distribution has been largely determined through gill netting and predator diet 

studies. Alewives in Claytor Lake are primarily pelagic-zone inhabitants, with highest densities in the 

lower lake (Nigro and Ney 1982). Mature fish move inshore in spring for spawning, then move back 

off-shore. Although regarded as pelagic zone fishes, alewives invade the littoral zone at night (Kohler 

and Ney 1981). Older alewife thermal requirements for cooler water temperatures (preferred 16-

20°C; Coutant 1977, cited in Ney et al. 1988) effectively limit their distribution to deeper offshore 

portions of Claytor Lake, where they are available for large pelagic predators such as walleye and 

striped bass with similar thermal requirements. Younger alewife exhibit a more plastic thermal 

regime (preferred temperature up to 25°C; Stewart and Binkowski 1986, cited in Ney et al. 1988), and 

so may be more common than adults in shallower areas that are warmer. 
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Alewife can succumb to cold water temperatures in some winters (Boaze and Lackey 1974; Kohler et 

al. 1986). During such winters, alewife may initially seek warmer water and move to the deeper 

portions of lakes (RMC 1992). In Claytor Lake and elsewhere, this can result in large alewife schools 

proximal to submerged water intakes. The result is entrainment of large numbers of alewife, as well 

as predators such as walleye that follow the schools (Boaze and Lackey 1974; RMC 1992). . 

5.1.10 Bluegill 

Bluegill represents the principal panfish species caught and harvested in Claytor Lake (Copeland 

1999). Bluegill catch was in excess of 108,000 fish, and more than 15,800 were harvested. Targeted 

panfish angling comprised 5% of overall effort. 

Bluegills are primarily littoral zone residents. Spawning is protracted, occurring from May through at 

least August, and nests are constructed in shallows on sand or gravel. Upon leaving nests, bluegill 

larvae migrate to limnetic surface waters, returning to littoral areas at approximately 25 mm in length 

(Werner 1967). Young are planktivores (Jenkins and Burkhead 1993; Werner 1969), and themselves 

are the primary food of the black basses (Bonds 2000). In lower Claytor Lake, juvenile and adult 

bluegill abundance would likely be highest at the back of coves where habitat < 5 m deep is most 

common, as shown in Nigro and Ney (1982). 

5.1.11 Black Crappie 

Although both crappie species exist in Claytor Lake, black crappie was likely targeted for this 

assessment since they are the dominant crappie species in the lower lake where turbidity is less 

(Kohler et al. 1986). Black crappie ranked third (2,411 total) among harvested fishes during the most 

recent creel survey (Copeland 1999). Given the harvest magnitude and high retention, black crappie 

exploitation is considered low, and recruitment is consistent (Copeland 1999). 

Black crappie are usually regarded as littoral zone residents, typically found in backwaters and other 

off-channel habitats, usually associated with in-water cover of some type. Historically, crappies were 

considered part of the pelagic predator assemblage in Claytor Lake (Kohler et al. 1986). Spawning 

occurs primarily in April in nests associated with cover (Jenkins and Burkhead 1993). Very young 

black crappie apparently undergo a migration from the spawning site to open limnetic habitat and 

then back to the littoral zone early in the first year, similar to bluegill (Werner 1967). Black crappie 

young represent a principal forage species for black basses which are also chiefly littoral zone 

inhabitants. In lower Claytor Lake, juvenile and adult black crappie abundance would likely be 

highest at the back of coves where cover and habitat < 5 m deep are most available, as shown in 

Nigro and Ney (1982). 

5.2 REVIEW OF ENTRAINMENT RATES DEVELOPED BY EPRI (1997) 

EPRI (1997) compiled fish entrainment data from the 43 selected sites listed in Table 4-1. As 

discussed above in Section 4.0, most of the sites were smaller than the Claytor Project in terms of 

individual unit size or plant capacity. Several projects were located in the south (seven), but only one 

project was located in Virginia (Luray). The compilation filtered site entrainment data through a 

range of acceptability criteria, such as: 
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 Requirement for utilization of full-flow netting 

 Sufficient data for seasonal analyses 

 Performance of net efficiency tests 

 Sufficient operational data to calculate entrainment densities 

 Lack of major study flaws such as net intrusion, extensive net damage, etc. 

The thorough data screening enabled calculation of reliable seasonal and annual estimated 

entrainment rates for fishes of three size groups. The annual estimated entrainment rates for small (< 

8 inches), medium (8-15 inches), and large (> 15 inches) fish for most of the species considered for 

this assessment are summarized in Table 5-1. The range of densities among included sites for a 

species were used by EPRI (1997) to develop a 5-step qualitative scale of entrainment potential from 

Low to Moderate to High. The qualitative rating was determined within the distribution of 

entrainment densities by identifying "break points". A different set of "break-points" from among 

higher density values were used to describe entrainment potential for small fish compared to medium 

and large fish since small fish are more abundant in a reservoir than either medium or large fish. 

Table 5-1. Average entrainment densities for Claytor Hydro Project fish species of interest 

drawn from EPRI (1997) entrainment database. Annual density standardized and 

shown as number of fish per million cubic feet of water. 

Small Fish (< 8 inches) Medium Fish (8-15 inches) Large Fish (>15 inches) 

No. Sites Annual Entrainment No. Sites Annual Entrainment No. Sites Annual Entrainment

Species/Surrogates Present Density Potential Present Density Potential Present Density Potential 

Alewife 3 34.057 High 3 0.078 Moderate-High 3 0.0 None 

Gizzard shad 10 15.668 High 10 0.220 High 10 0.0047 Moderate 

Bluegill 36 0.925 Moderate-High 36 0.005 Moderate 36 0.0000 Low 

Black crappie 30 0.400 Moderate-High 30 0.013 Moderate-High 30 0.0000 Low 

Walleye 29 0.120 Moderate-High 29 0.026 Moderate-High 29 0.002 Low-Moderate

Largemouth bass1 34 0.118 Moderate-High 34 0.002 Low-Moderate 34 0.0032 Moderate 

Smallmouth bass1 34 0.090 Moderate 34 0.008 Moderate 34 0.0005 Low 

White perch2 4 0.224 Moderate-High 4 0.183 High 4 0.0000 Low 

White bass2 4 0.003 Low 4 0.042 Moderate-High 4 0.0 Low 

Striped bass NA 

Hybrid striped bass NA 

Spotted bass NA 

Footnotes (also see text): 

NA = no sites in EPRI database reported this species in entrainment catch 

1

 Potential surrogate species for spotted bass 

2

 Potential surrogate species for striped bass and hybrid striped bass. 
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The entrainment densities and associated entrainment potential shown in Table 5-1 represent up to 36 

sites per target species without regard to variations in local conditions (e.g., intake configuration, 

reservoir size, etc.) that may influence entrainment. Further, not all species of management interest 

within the Claytor Project were represented in the EPRI (1997) database. As a result, we assumed that 

information deemed relevant for several species considered herein were represented by surrogate 

species included in the EPRI (1997) review. The surrogate species and the Claytor Project species 

they represent are listed as footnotes to Table 5-1. 

As would be expected, small fish densities were substantially higher than for medium and large fish 

(Table 5-1). In fact, most field studies included in data compilations have shown that entrainment is 

highest for fish less than 4 inches (FERC 1995; Winchell et al. 2000). Alewife and gizzard shad 

generally have the highest potential for entrainment in reservoirs where they are abundant. For both 

clupeid species, entrainment density peaks occurred in either the fall or winter, typically when they 

become lethargic due to cold water temperatures. The potential for entrainment of small bluegill and 

black crappie, walleye, and largemouth bass was Moderate-High. Entrainment density for these 

species tended to be higher in summer (EPRI (1997) or fall (FERC 1995), suggesting dispersal of 

young as the primary factor. Smallmouth bass entrainment risk also was highest in summer, although 

the overall risk was rated as Moderate. The young of each of these species, particularly the 

centrarchids, are considered primarily littoral zone inhabitants. 

Spotted bass were not represented among any of the EPRI (1997) source studies. Although their 

habitat requirements are intermediate between smallmouth bass and largemouth bass, spotted bass 

tend to be more abundant in upper Claytor Lake (see Section 5.1.6). Given this, the entrainment 

potential of young spotted bass is most likely no more than Moderate. 

The entrainment potential of white bass was judged Low based on the limited EPRI (1997) data 

(Table 5-1). White bass young are typically produced in reservoir headwaters or tributary arms 

(DiCenzo and Duval 2002), which might account for their overall low entrainment rate. 

Although in the same genus as striped bass, white bass alone as a surrogate for striped bass or hybrid 

striped bass may lead to an underestimate of entrainment potential for the young of these two stocked 

species. Stocked striped bass and, particularly, hybrid striped bass, are known to readily escape inland 

reservoirs and establish fisheries in downstream reaches, as has occurred in the New River and 

elsewhere (Van Den Avyle and Higginbotham 1979; Gleason 1982). As a result, white perch, another 

Morone species, was included to possibly bracket entrainment potential. Small white perch exhibited 

a Moderate-High entrainment potential rating based on the four studies that included white perch in 

EPRI (1997). Therefore, the entrainment potential of young striped bass and hybrid striped bass may 

be intermediate between white bass and white perch, and appropriately described as Moderate, given 

their acknowledged rapid dispersal from stocking sites in the mid-reservoir area (Rash 2003). 

Although annual entrainment densities were substantially lower for all fish > 8-15 inches except 

white bass, and only moderately lower for white perch, several species retained a qualitative potential 

rating of High or Moderate-High. These include gizzard shad, alewife, black crappie, walleye, white 

perch and white bass. In particular, use of the white perch entrainment rate to develop a representative 

rate for medium-sized striped bass and hybrids striped bass might be problematic.However, though 

the qualitative potential for entrainment of medium or large fish relative to small fish may be 

comparable for some species, the numbers of many fishes > 8 inches that are available for 
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entrainment, including the Morone taxa, black crappie, and particularly alewife and gizzard shad, are 

relatively low. 

The entrainment potential among all large-sized fishes considered was no more than Moderate. For 

species like alewife and bluegill, fish >15 inches don’t exist. The swimming ability of adults of most 

of the other species of interest (see Section 3.0) would be expected to preclude entrainment at the low 

prevailing approach velocities. 

5.2.1 Projections of Entrainment Losses 

The average annual entrainment densities shown in Table 5-1 were used with annual turbine flow data 

to extrapolate to estimates of fish lost from each reservoir due to turbine entrainment. A dry year and 

a wet year were selected by AEP to illustrate potential bounds for fish loss estimates. Annual Claytor 

turbine flow data were provided by Appalachian Power operations staff for a recent dry year (2007) 

and representative wet year (2003). Claytor turbine flow was 66.824 billion cubic feet of water in 

2007 and 152.19 billion cubic feet of water in 2003. Turbine flow during a wet year was more than 

twice that in a dry year. Other factors that can affect the amount of generation in a year such as 

planned or unplanned outages for equipment repairs or upgrades are mentioned here but not 

considered further. 

Estimated fish losses from Claytor Lake due to turbine entrainment without regard to variability in 

fish passage survival (discussed later in Section 5.4) are shown in Table 5-2. As expected, the prolific 

prey species alewife and gizzard shad dominate estimated entrainment losses. Projected game fish 

losses were substantially less. For all fishes, entrainment losses would generally be expected to be 

higher in years with higher precipitation and increased runoff that enables more generation. It is also 

important to note that fish losses are primarily of small fish, and that survival of these small fish is 

typically quite high (see Section 5.4). 

Two Morone species, white bass and white perch, served as surrogates to develop bracketed estimates 

of striped bass and hybrid striped bass entrainment losses. This was done due to the lack of 

quantitative striped bass or hybrid striped bass entrainment data in available literature. The estimated 

losses in Table 5-2 were calculated by using white bass and white perch data each from four qualified 

projects reviewed by EPRI (1997). Juvenile white bass entrainment at these projects was low, 

whereas white perch entrainment was much higher. White bass young are produced in project 

headwaters, perhaps spatially isolated at their most vulnerable life stage by distance from turbine 

intakes. White perch are likely not as spatially isolated in reservoirs, and through natural reproduction 

can achieve high abundance leading to stunting in land-locked situations (e.g., Hergenrader and Bliss 

1971, in Nebraska). The white perch in Nebraska also quickly propagated downstream. Additionally, 

studies at Richard B. Russell Project in South Carolina/Georgia estimated white perch entrainment 

(pump-back) more than 50 times higher than estimated for striped bass or striped bass hybrids 

(Nestler et al. 1998). Although striped bass and hybrid striped bass also establish fisheries 

downstream as noted for white perch, both species are stocked in Claytor Lake at controlled densities. 

Thus, entrainment of small striped bass and hybrid striped bass may be higher than shown for white 

bass, but almost certainly less than if white perch were used as the sole surrogate. Thus, to be 

conservative, the midpoint of the densities shown for white perch and white bass in Table 5-1 were 

used to estimate the losses in Table 5-2. 
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Higher losses of medium-sized white bass than smaller individuals, and (by surrogate) higher than 

expected losses of medium-sized striped bass and hybrid striped bass represent other apparent 

anomalies in Table 5-2. Striped bass and hybrid striped bass, largely due to the inclusion of white 

perch as a surrogate, also exhibited comparatively high entrainment densities of medium-sized fish. 

Table 5-2. Estimated entrainment losses for Claytor Lake fish species of interest. Annual 

density standardized and shown as number of fish per million cubic feet of water. 

Small Fish (< 8 inches) Medium Fish (8-15 inches) Large Fish (> 15 inches) 

DRY YEAR 

Species/surrogates 

Annual 

Density 

Entrainment 

Losses 

Annual

Density 

Entrainment 

Losses 

Annual 

Density 

Entrainment 

Losses 

Alewife 34.057 2,275,830 0.078 5,212 0.0 0 

Gizzard shad 15.668 1,047,001 0.220 14,701 0.0047 314 

Bluegill 0.925 61,812 0.005 334 0.0000 0 

Black crappie 0.400 26,730 0.013 869 0.0000 0 

Walleye 0.120 8,019 0.026 1,737 0.002 134 

Largemouth bass 0.118 7,885 0.002 134 0.0032 214 

Smallmouth bass 0.090 6,014 0.008 535 0.0005 33 

Spotted bass1 0.104 6,950 0.005 334 0.0018 120 

Striped bass2 0.1135 7,585 0.1125 7,518 0.0005 33 

Hybrid striped bass2 0.1135 7,585 0.1125 7,518 0.0005 33 

White bass 0.003 200 0.042 2,807 0.0 0 

Small Fish (< 8 inches) Medium Fish (8-15 inches) Large Fish (> 15 inches) 

WET YEAR 

Species/surrogates 

Annual 

Density 

Entrainment 

Losses 

Annual 

Density 

Entrainment 

Losses 

Annual 

Density 

Entrainment 

Losses 

Alewife 34.057 5,183,152 0.078 11,871 0.0 0 

Gizzard shad 15.668 2,384,521 0.220 33,482 0.0047 715 

Bluegill 0.925 140,776 0.005 761 0.0000 0 

Black crappie 0.400 60,876 0.013 1,978 0.0000 0 

Walleye 0.120 18,263 0.026 3,957 0.002 304 

Largemouth bass 0.118 17,958 0.002 304 0.0032 487 

Smallmouth bass 0.090 13,697 0.008 1,218 0.0005 76 

Spotted bass1 0.104 15,828 0.005 761 0.0018 274 

Striped bass2 0.1135 17,274 0.1125 17,121 0.0005 76 

Hybrid striped bass2 0.1135 17,274 0.1125 17,121 0.0005 76 

White bass 0.003 457 0.042 6,392 0.0 0 

1

 Midpoint of largemouth bass and smallmouth bass density used to calculate potential losses of spotted bass. 2

 Midpoint of white perch and white bass density used to calculate potential losses of striped bass and hybrid striped bass. 

Winchell et al. (2000), in his summarization of the EPRI (1997) entrainment database, suggested that 

despite best efforts to prevent tailrace net intrusion, some larger fish densities may have been 

affected by fish entering the net from downstream. The moderately high densities of medium-sized 

white bass and white perch likely reflect net intrusion, since peak entrainment catches of both species 

occurred in spring during the spawning period (EPRI 1997). Such higher entrainment densities of 

medium-sized fish are not only counterintuitive but opposite the data trends identified for other 

species in numerous field studies. In addition, the swimming abilities of 8-15 inch striped bass and 
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hybrid striped bass are substantially better than the surrogate white perch, such that losses of striped 

bass and hybrid striped bass portrayed in Table 5-2 are probably overestimated. 

5.3 BLADE STRIKE AND CAVITATION POTENTIAL OF EXISTING UNITS

Blade strike or contact with turbine structural elements is the most likely mode of injury or mortality 

for fishes passing through the turbines (e.g., Eicher Associates 1987). Other possible injury/mortality 

sources less likely to harm fish include shear forces and changes in pressure (e.g., Cada 1990). 

Changes in pressure within the turbine can result from cavitation. Cavitation potential is related to 

“plant sigma”, which is related to the elevation (siting) of the turbine relative to minimum tailrace 

elevation. The risk of injury/mortality due to cavitation is addressed below. Additionally, for the more 

likely collisions with structural elements, the strike probability assessment using the Franke et al 

(1997) formula described below relates fish size (primarily) to water passage spaces in the turbine, 

and most likely predicts blade or mechanical strike potential. 

5.3.1 Strike Probability using Predictive Model 

The formula developed by Franke et al. (1997) grew out of efforts for the Department of Energy 

(DOE) to design more “fish-friendly” turbines. The formula calculates the probability (P) of blade 

strike by relating such turbine parameters as the number of buckets, runner diameter, and runner 

height to fish length and operating condition. Fish length and available passage space are the principal 

drivers of the output. The paramters of interest for the large Francis units at the Claytor Project are 

shown in Table 5-3. Other than manufacturer, the units differ only slightly in runner diameter (2.8%). 

For this exercise, eight representative fish lengths, two operating conditions, and two correlation 

factors were selected. The operating conditions were unit design flow (2,500 cfs) and MEP flow 

(2,000 cfs). The correlation factors used were 0.10 and 0.15; these are used to account for variability 

in strike potential and also to relate the output to empirical data available to the Franke study. 

Although the formula calculates a probability, in the present context it is more conventionally used in 

the formula Survival (S) = 1 – P, with results expressed as a survival percentage. 

Table 5-3. Values of turbine parameters used in blade strike and survival estimates. 

Claytor Lake Turbines 

Parameter Unit No. 1, 2 Unit No. 3, 4 

Turbine type Francis Francis 

No. blades/buckets 15 15 

Max. turbine discharge (cfs) 2,500 2,500 

Turbine discharge (cfs) at best efficiency 2,000 2,000 

Runner diameter at inlet (ft) 8.8 9.0 

Runner diameter at discharge (ft) 10.9 11.2 

Runner height at inlet (crown) (ft) 6.3 6.3 

Best turbine efficiency (%) 92 92 

RPM 138.5 138.5 

Head (ft) 116 116 
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The results applied to the Claytor units show that strike potential is low and expected survival is quite 

high for the mostly small fish likely to be entrained (Table 5-4). For example, at the MEP flow of 

2,000 cfs and either unit type, predicted survival for small fish < 8 inches long (average of survival 

for 2, 4, and 6-inch fish) is 94% to 96%. The data also show that survival may be nearly as high for 

units operated at 2,500 cfs, and also that survival decreases as fish length increases. Both results 

conform to expectations. The water pathway is less turbulent at efficient flow, meaning smaller forces 

are acting on the fish, and larger fish are more likely to contact a turbine element in a confined space. 

These modeled predictions may be compared to survival results determined in the field for similar 

sized fish (see Section 5.4 below). For comparison purposes, immediate survival results from field 

studies provide the most appropriate parallel, because these reflect fish condition immediately after 

turbine passage. The modeled data are generally quite similar to field study results and reflect the 

survival trends shown in Section 5.4 with particular reference to fish size. 

5.3.2 Cavitation Potential 

Cavitation occurs within the turbine environment. Most hydro plants are designed to minimize the 

likelihood of cavitation due to the costs of efficiency loss and the cost of repairs to turbine runners. 

Design issues or extreme operating conditions create sub-atmospheric pressures that typically damage 

metal turbine blades. Cavitation occurs in small areas of the runner, and damage to fish can result 

from intense shock waves emanating from collapsing bubbles or vapor pockets. Tests have shown, 

however, that the zone of cavitation is small, and fish passing through the turbine must be close to the 

shock wave to be damaged (Eicher Associates 1987; Cada 1990). 

Operations staff were queried about cavitation damage to Claytor turbine runners, as a gauge of the 

potential for cavitation to damage fish during passage. Cavitation repairs are a minor occurrence at 

the Claytor Project; repairs are needed on about a decadal frequency (J. Thrasher, Appalachian, 

personal communication). As a result, fish injury or mortality due to the effects of cavitation would 

likely be minimal. 

5.4 TURBINE PASSAGE SURVIVAL ASSESSMENT

5.4.1 EPRI (1997) Data 

Fish size more so than species has emerged as the key decision variable for a given turbine type and 

operational characteristics (see also Franke et al. 1997). Winchell et al. (2000) summarized empirical 

turbine passage survival data reported in the EPRI (1997) database by turbine type and characteristics 

and fish size. The survival rates reported reflect trends from field tests at up to 19 turbines per size 

class of test fish that met specific acceptability criteria for control fish mortality (could not exceed 

10%). These survival data are reproduced herein for the studies representative of the four similar 

Francis turbines housed in the Claytor Project (Table 5-5). The four Claytor turbines are large (runner 

diameter about 11 ft, hydraulic capacity of 2,000 cfs at most efficient operation), and rotate slowly 

(138.5 rpm). 

Immediate survival after passage was rated as High for two size groups of fish up to 7.8 inches (199 

mm). Medium sized fish averaged 86.9% survival in 18 tests; risk was rated as Moderate. Survival 

was rated as Low (mean = 73.2%) for larger fish (> 11.8 inches). Survival declined a few percentage 
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Table 5-4. Predicted turbine passage survival at Claytor Project turbines based on the blade 

strike probability formula developed by Franke et al. (1997). 

Units 1, 2 Units 3, 4 

Unit Correlation Fish Survival Unit Correlation Fish Survival

Flow-cfs Factor Length-in (%) Flow-cfs Factor Length-in (%) 

2,000 0.1 2 98.1% 2,000 0.1 2 98.1% 

 4 96.3% 4 96.3% 

 6 94.4% 6 94.4% 

 8 92.6% 8 92.6% 

 10 90.7% 10 90.7% 

 12 88.8% 12 88.9% 

 18 83.3% 18 83.3% 

 24 77.7% 24 77.7% 

2,000 0.15 2 97.2% 2,000 0.15 2 97.2% 

 4 94.4% 4 94.4% 

 6 91.6% 6 91.6% 

 8 88.8% 8 88.8% 

 10 86.1% 10 86.1% 

 12 83.3% 12 83.3% 

 18 74.9% 18 74.9% 

 24 66.5% 24 66.6% 

2,500 0.1 2 98.0% 2,500 0.1 2 97.9% 

 4 95.9% 4 95.9% 

 6 93.9% 6 93.8% 

 8 91.8% 8 91.8% 

 10 89.8% 10 89.7% 

 12 87.8% 12 87.7% 

 18 81.7% 18 81.5% 

 24 75.6% 24 75.4% 

2,500 0.15 2 96.9% 2,500 0.15 2 96.9% 

 4 93.9% 4 93.8% 

 6 90.8% 6 90.8% 

 8 87.8% 8 87.7% 

 10 84.7% 10 84.6% 

 12 81.7% 12 81.5% 

 18 72.5% 18 72.3% 

 24 63.3% 24 63.1% 
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Table 5-5. Mean fish survival rates for Francis turbines and representative fish sizes in EPRI 

database (source: Winchell et al. 2000). 

Turbine Average Immediate Survival-all species (%)

Type 

Runner 

Speed (rpm) 

Hydraulic 

Capacity (cfs) 

Fish Sizemm (in) N Minimum Maximum Mean Survival

Potential**

Francis <250 440-1,600 <100 (3.9) 13 85.9 100 93.9 High 

(radial-flow) 370-1,600 100-199 (3.9-7.8 19 74.8 100 91.6 High 

 370-2,450 200-299 (7.9-11.8) 18 59.0 100 86.9 Moderate 

 440-1,600 300+ (11.8+) 14 36.1 100 73.2 Low 

Average Survival (after 48 h)-all species (%) Turbine 

Type 

Runner 

Speed (rpm) 

Hydraulic 

Capacity (cfs) 

Fish Sizemm (in) N Minimum Maximum Mean Survival

Potential**

Francis <250 440-1,600 <100 (3.9) 11 80.9 100 90.4 High 

(radial-flow) 370-2,450 100-199 (3.9-7.8 17 73.7 100 87.8 Moderate 

 440-2,450 200-299 (7.9-11.8) 15 47.4 96.4 80.4 Moderate 

 440-1,600 300+ (11.8+) 13 33.8 94.1 66.8 Low 

** Qualitative survival rating: High = 90-100%; Moderate = 80-89.9%; Low = <80%. 

points when fish were held for at least 48 h for delayed analysis, yet survival for all fish up to 3.9 

inches remained High (Table 5-3). 

5.4.2 Additional Empirical Survival Data 

Empirical fish passage survival studies for species representative of those considered at the Claytor 

Project were examined to augment the EPRI survival data. Results were compiled from six additional 

sites with Francis turbines. Most of the turbine characteristics at the studied units bracketed those at 

Claytor Hydro Project, including number of runner buckets, runner speed (rpm) and runner diameter 

(Table 5-6). All were single-runner turbines except for those at Finch Pruyn (double and quad runner) 

and Holtwood Unit 3 (double). The operating head at each of the compiled studies was less when 

compared to the 116 ft of head at the Claytor Project. The species studied were either target species 

identified for the Claytor assessment (e.g., smallmouth bass, bluegill), or reasonable surrogates (Table 

5-7). American shad and blueback herring were considered surrogates for alewife and gizzard shad 

due to similar shape and fragility. Fusiform fishes such as channel catfish, yellow perch, and suckers 

were considered surrogates for walleye and young striped bass due to comparable body shape. Mean 

size of fish tested ranged from 90 mm TL (bluegill) to 271 mm TL (smallmouth bass). Survival 

during turbine passage was determined using balloon tag technology (Heisey et al. 1992). 

Survival of the large majority of species/sizes tested exceeded 90% (Table 5-7). These data agree 

with those summarized for Francis turbines in Section 5.4.1 above for the mostly small sizes of fish 

typically entrained. As discussed in Winchell et al. (2000) and elsewhere (e.g., Heisey et al.1996), 

there was little difference in survival rate among species tested. Survival was high for small and 

medium-sized fish of a variety of species. 

5.4.3 Estimated Annual Fish Mortality 

Compiled 48-h fish survival data in Table 5-5 were applied to estimated entrainment losses from 

Table 5-2 to estimate annual fish mortality due to turbine passage. Survival rates (S) for both groups 

of small fish (< 8 inches) were averaged. Survival rates for medium and large fish were those shown 
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Table 5-6. Site characteristics of empirical studies at Francis installations not reviewed in 

EPRI database. All studies performed using balloon tag technology. 

Station/location Turbine flow-cfs No. buckets Runner speed-rpm Head-ft Runner diameter-ft 

Columbia, SC 833 14 164 28 5.33 

Finch Pruyn, NY (Unit 4) 708 15 225 46 3.00 

Finch Pruyn, NY (Unit 5) 836 15 225 46 3.00 

Holtwood, PA (Unit 10) 3,500 16 94.7 62 12.46 

Holtwood, PA (Unit 3) 3,500 17 102.8 62 9.33 

Stevens Creek, SC 1,000 14 75 28 11.25 

Vernon, VT/NH 1,834 15 74 34 13.00 

White Rapids, WI 900 14 100 29 11.17 

Table 5-7. Immediate (1-h) survival of representative fish species at Francis installations not 

reviewed in EPRI database. All studies performed using balloon tag technology. 

Species Station/location Mean fish length-mm Est. Percent Survival-1h 

Smallmouth bass Finch Pruyn, NY (Unit 4) 191 95 

Finch Pruyn, NY (Unit 4) 210 91 

Finch Pruyn, NY (Unit 4) 271 93 

Finch Pruyn, NY (Unit 5) 191 94 

Finch Pruyn, NY (Unit 5) 210 91 

 Finch Pruyn, NY (Unit 5) 271 71 

Bluegill Stevens Creek, SC 122 95.4 

 White Rapids, WI 90 95 

 White Rapids, WI 155 100 

Sunfishes (Lepomis) Columbia, SC 106 95.9 

Alosids 

American shad Holtwood, PA (Unit 10) 125 89.4 

Holtwood, PA (Unit 3) 125 83.5 

 Vernon, VT/NH 95 94.7 

Blueback herring Stevens Creek, SC 203 95.3 

Fusiform shape 

Channel catfish Columbia, SC 143 93.6 

Spotted sucker/yellow perch Stevens Creek, SC 165 98.3 

White sucker White Rapids, WI 112 100 

 White Rapids, WI 204 93 

for 7.9-11.8-inch fish and fish > 11.8 inches, respectively. Estimated entrainment losses were 

multiplied by the mortality rate (1-S) to estimate mortality. 

Fish mortality in any given year would primarily be small alewife, gizzard shad, bluegill, and black 

crappie (Table 5-8). Comparatively little mortality for fish larger than 8 inches other than gizzard 

shad and alewife would be expected. As noted for the reasons discussed previously (use of white 

perch as one surrogate species for stocked striped bass and hybrid striped bass), the annual mortality 
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losses estimated for medium-sized and larger striped bass and hybrid striped bass likely represent 

overestimates. 

Table 5-8. Estimated annual mortality due to turbine passage for Claytor Lake fish species of 

interest. The source of mortality rates was Winchell et al. (2000). 

Small Fish (< 8 inches) 

Mortality Rate = 10.9% 

Medium Fish (8-15 inches)

Mortality Rate = 19.6% 

Large Fish (> 15 inches) 

Mortality Rate = 33.2% 

Species/Surrogates Dry Year Wet Year Dry Year Wet Year Dry Year Wet Year 

Alewife 248,065 564,964 1,022 2,327 0 0 

Gizzard shad 114,123 259,913 2,881 6,562 104 237 

Bluegill 6,738 15,345 65 149 0 0 

Black crappie 2,914 6,636 170 388 0 0 

Walleye 874 1,991 341 776 44 101 

Largemouth bass 859 1,957 26 60 71 162 

Smallmouth bass 656 1,493 105 239 11 25 

Spotted bass1 758 1,725 65 149 40 91 

Striped bass2 827 1,883 1,473 3,356 11 25 

Hybrid striped bass2 827 1,883 1,473 3,356 11 25 

White bass 22 50 550 1,253 0 0 

1

 Annual mortality of spotted bass based on use of largemouth bass and smallmouth bass as surrogates; see Table 5-2. 2

 Annual mortality of striped bass and hybrid striped bass based on use of white bass and white perch as surrogates; see 

Table 5-2. 
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6.0 OVERALL ENTRAINMENT ASSESSMENT

The Claytor Hydro Project was assessed with respect to both entrainment and turbine passage 

mortality. The assessment examined individual characteristics among dam, intake, and hydroplant 

structural elements, reservoir characteristics, and fish populations that can affect entrainment and 

mortality. Various comprehensive reviews of entrainment and mortality data (FERC 1995; EPRI 

1997) as well as fish behavior relative to turbine passage (Coutant and Whitney 2000) suggest that 

one or more of the factors listed in Table 6-1 may influence the risk of turbine passage entrainment or 

mortality. Among factors that can influence entrainment rates, this assessment examined the 

following: 

Table 6-1. Comparison of factors that may influence entrainment or survival rates at Claytor 

Hydro Project. 

Influence Factors Claytor Project 

Entrainment Rates

Intake adjacent to shoreline No 

Intake location in littoral zone No 

Abundant littoral zone fishes (no. species) Yes 

Abundant littoral zone fishes (no. individuals) Yes 

Abundant clupeids Yes 

Obligatory migrants No 

Intake depth-ft (at top, full pond) 14 

Winter drawdown No 

Normal hydraulic capacity (cfs) 8,000 

Approach velocity (ft/s, normal operation) ≤ 1.5 

Water quality factor Yes 

Risk of Entrainment 

High/ 

Moderate-High* 

Survival Rates

Turbine type Francis 

High turbine speed No 

Survival rates of small fish (<8 in) Moderate-High 

Pressurized intake tunnel Yes 

Risk of Mortality Low-Moderate 

* Mainly clupeids, alewives and young centrarchids 

 Intake adjacent to shoreline--Nearshore intakes typically entrain fishes at higher rates 

than offshore intakes, as fish tend to follow shorelines or orient to physical structure 

associated with shorelines. 

 Intake location in littoral zone--The littoral zone is the most productive region of a 

reservoir and most fish rear in the shallower littoral areas. 
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 Abundant littoral zone species--Fishes such as centrarchids that spawn, rear, and spend 

most of their lives in shallow nearshore waters tend to be among the most abundant 

species in a fish assemblage. 

 Abundant clupeids--Entrainment rates trend highest at projects with clupeids such as 

gizzard shad and/or alewife. 

 Intake depth--Fish are usually more abundant in shallower portions of a reservoir 

throughout most of the year. 

 Winter drawdown--Drawdown of a reservoir to provide storage of winter and spring 

runoff reduces reservoir volume and may place fishes in closer proximity to water 

intakes. 

 Hydraulic capacity--More water passed through intakes will entrain more fish for a given 

entrainment rate. 

 Water quality factor--poor water quality (e.g. low dissolved oxygen in the hypolimnion) 

in a reservoir may form a barrier and reduce fish susceptibility to entrainment. 

 Approach velocity--approach velocities may positively correlate with entrainment rates, 

although FERC (1995) was unable to find a significant trend between entrainment rate 

and intake velocity. Other factors related to intake siting may be more important. Herein, 

approach velocity is considered at the plane of the water intake opening. 

 Presence of obligatory migrants. “Resident” fishes are usually entrained inadvertently but 

relative to their use of near-intake habitats. Migrants out of freshwater systems must 

locate an exit route and turbine intakes provide the bulk flow cues used to guide 

outmigration. 

Factors examined that can influence fish survival/mortality during turbine passage included: 

 Turbine type--Among factors related to passage survival, the size of water passage spaces 

available relative to fish size influences susceptibility to contact with structural elements. 

Francis runners have more closely spaced buckets/blades than Kaplan/propeller runners 

and thus spaces available for passage are smaller, particularly relevant for larger-sized 

fish in Francis turbines. 

 High turbine speed--Higher rpm's increase the likelihood of contact with structural 

elements. 

 Survival rate of small fish (<8 in)--More than 90% of fishes entrained at hydro projects 

are small (EPRI 1997). High survival of small fish reduces the overall impact of 

entrainment to fish populations. 

 Pressurized intake tunnel--High hydrostatic pressure in penstocks at high head sites 

(>100 ft) may be suddenly released as fish acclimated to higher pressure pass from 

pressurized areas or deep water to tailwaters at normal hydrostatic pressure. The sudden 

relief from high pressure increases the risk to fish of decompression trauma. 

The Claytor project reservoir and turbines are examined below with respect to those unique features 

listed above that may affect fish entrainment or mortality. 

The fish entrainment potential at the Claytor Hydro Project is rated Moderate to Moderate-High, 

principally due to abundant clupeids as well as numerous and abundant centrarchid species such as 

bluegill and crappie (see Section 5.1). Young alewife and gizzard shad (1.5 to 4 inches), as well as 

young bluegill and crappie (< 4 inches), typically form the bulk of entrainment catches where they are 

abundant in hydropower reservoirs (FERC 1995). Young clupeids form dense, large, open-water 
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schools and both clupeid species in Claytor Lake tend to be susceptible to torpor due to cold water 

temperatures. As a result, entrainment of shad tends to be episodic due to the clumped reservoir 

distribution (schooling behavior), and more prevalent during fall and winter. Natural movements of 

clupeids may also increase the risk of entrainment to those predatory species utilizing shad as prey. 

Young clupeids in fall and winter, including those stressed by cold water, may move to deeper waters 

of the reservoir seeking warmer water. Movements to the lower portions of the reservoir may increase 

exposure of alewife and gizzard shad and the predatory fishes that follow schools of these forage 

species to water proximal to the intakes, thus increasing the risk of entrainment. Boaze (1972) 

previously documented alewife winter entrainment due to cold stress. 

In some reservoirs, such winter losses may be exacerbated by reduced reservoir volume during winter 

drawdown. Routine winter drawdown to increase storage does not occur at Claytor Lake, although 

brief fall drawdowns for shoreline structure maintenance or ad hoc drawdowns to accommodate 

expected high inflows do occur. Such occurrences, by their brief nature, would not likely increase 

entrainment risk substantially. 

Young centrarchids such as bluegill and crappie tend to be very abundant in shoreline areas and in 

shallow water, and are usually major contributors to entrainment. However, the mean entrainment 

densities of small bluegill and black crappie shown in Table 5-1 are nowhere near the densities 

typical for clupeids, thus the rating “Moderate-High”. Although centrarchid entrainment can be 

substantial, Claytor Lake is moderately eutrophic and productive, and sustains large, diverse fish 

populations. Despite the “Moderate High” fish entrainment potential for several popular sport species 

(based on empirical studies elsewhere) Claytor Lake supports good recreational fishing for such 

species as bluegill and largemouth bass. The reservoir provides a “forage-rich” environment that 

supports these popular sport fisheries. 

The Claytor Project intakes withdraw from moderately deep water. The intake ceiling is 14 ft below 

normal pool level, and extends to 61 ft deep; intake centerline is 37.5 ft below normal pool. Whereas 

deep (e.g., >60 ft) intakes may be isolated from areas of fish abundance, shallower intakes are in 

closer proximity to the reservoir areas where fish are most abundant. However, the Claytor Hydro 

intakes are removed from the limited littoral zone areas of the lake. The Claytor Hydro intakes are 

separated from the right (descending) shoreline by several hundred feet of bulkhead, and from the left 

shoreline by the extensive spillway section. Thus, relatively shallow water withdrawals (compared to 

near-dam pool depth) may be mediated by the distance from and limited area of littoral zones. The 

distance from and relatively low abundance of littoral areas is one of the prime factors that would be 

expected to limit entrainment and yield the overall risk profile of Moderate to Moderate-High. 

Water quality is at most a seasonal deterrent to fish entrainment out of Claytor Lake. Years of low 

inflow result in dissolved oxygen depletion during warm months at depths below 5 to 10 m (16 to 33 

ft), approximately equivalent to the upper portion of the intakes. Fish would avoid these areas of poor 

water quality and avoid potential entrainment through intakes at these depths. Avoidance of intake 

areas due to poor water quality would likely not occur during years or seasons of higher inflow or 

cooler temepratures when dissolved oxygen is also higher. 

Water velocity at the project intakes is considered moderate as calculated on historical project 

drawings and determined by field studies. Intake area field studies identified intake velocities less 

than about 1.5 ft/s as close as 40 ft up-lake during full generation. Water velocities then increase 

toward the plane of the dam face to where intake openings are located (1.50 ft/s) and to the trash bar 
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racks (2.40 ft/s). The withdrawal volume (normal full load discharges 8,000 cfs) is large. Although 

the larger water volumes would likely entrain more fish for a given entrainment rate, the 

comparatively low water velocities where fish might encounter withdrawal acceleration would mean 

that all but the poorest swimmers, such as young fish, could escape unless swimming ability (or 

behavioral avoidance) was compromised by cold water temperatures. 

Claytor Project head is 116 ft, somewhat higher than the maximum head (100 ft) typically ascribed to 

low head hydro projects. The moderately high head pressurizes the penstocks, so that maximum 

pressure during operation is developed just in front of the turbine runners (44.5 psi; J. Thrasher, 

Appalachian, personal communication). Studies have shown that shallow water intakes and passage 

of fish acclimated to near normal atmospheric pressure enhances survival since entrained fish are not 

acclimated to deep water and high hydrostatic pressure and, thus, are not forced to equilibrate to rapid 

reductions to normal pressure when passed into a hydro station tailrace (Cada 1990; Franke et al. 

1997). Most of the Claytor Lake fish would be expected to be entrained from impoundment surface 

layers (to approximately 30 ft deep), and the rapid transit time through the turbine (due to nearvertical fall of water) precludes the need for fish to make adjustments in swim bladder volume to 

accommodate pressure changes. Any injury or mortality due to the pressure changes experienced 

would be minimal (Cada 1990). A potential exception would be when fish acclimated to deep water, 

such as alewives seeking warmer water temperatures in late fall or winter or predator species 

following alewife schools, are inadvertently entrained. The sudden release to normal atmospheric 

pressure of the tailrace has caused decompression trauma elsewhere (RMC 1994). However, the lack 

of any history of such occurrences in the Claytor tailrace since alewife were introduced suggests this 

is not a common occurrence. 

Four vertical Francis turbines are housed at the Claytor Project. All units are similar in size (large) 

and rotate slowly (138.5 rpm). Fish survival is higher at hydro projects with low speed turbines (EPRI 

1997; Winchell at al. 2000). The summaries of turbine survival data from Winchell et al. (2000) in 

Table 5-5 supplemented by several additional empirical survival studies (Table 5-7), clearly identify 

high (≥ 90%) survival of the mostly small fish that pass through project turbines. Thus, the risk to 

most fish passing through the turbines would be moderately Low. 
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7.0 CONCLUSIONS

Popular multi-species fisheries characterize the Claytor Hydro Project reservoir. Black basses, 

walleye, catfishes, and panfish naturally reproduce; these species are augmented annually with striped 

bass and hybrid striped bass fingerlings to take advantage of abundant clupeid prey species. Some 

level of fish entrainment was assumed prior to this investigation, particularly for the stocked predators 

and clupeid prey species, but entrainment was not believed to be a problem due to the mostly robust 

lake sport fisheries. Fish kills due to turbine passage are lacking. Swim speed information coupled 

with engineering calculations and field intake velocity measurements suggest small juvenile fishes, 

those less than 8 inches long, are the most vulnerable to entrainment. Larger individuals, principally 

the stocked predators, generally possess the swimming ability to avoid velocities near the intakes. 

Entrained fishes would comprise mostly prey species such as alewife and gizzard shad. Entrainment 

of young sunfish such as bluegill and crappie is also likely, but moderated by intake separation from 

shorline littoral areas where they are typically most abundant. Stocked predators such as walleye, 

striped bass, and hybrid striped bass may be entrained as smaller juveniles, but older, larger fish are 

most likely to avoid entrainment through better swimming ability. The survival of the mostly small 

fish passing out of the lake would be expected to be high based on model calculations and evidence 

accumulated elsewhere for similar turbines and similar-sized fishes. Due to the inter-annual 

differences in water volume passed through the Claytor Project turbines, more than a factor of two, 

fish lost to the New River downstream would likely be higher in years with higher project inflows and 

annual discharge. 
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8.0 LITERATURE CITED

8.1 SWIM SPEED LITERATURE IN TABLE 3-1 AND SECTION 3.1 

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