PRELIMINARY ASSESSMENT OF FISH ENTRAINMENT 

AT HYDROPOWER PROJECTS 

A Report on Studies and Protective Measures 

Volume 1 

Federal Energy Regulatory Commission 

Office of Hydropower Licensing 

Washington, DC 

Paper No. DPR-10 

June 1995 
Stone & Webster Environmental Technology & Services prepared this report, and it does 

not necessarily reflect the views of the staff of the Federal Energy Regulatory Commission. 
Preliminary Assessment of Fish Entrainment at Hydropower Projects - A Report on Studies 

and Protective Measures 

This report deals with fish entrainment at hydropower projects. Entrainment is important 

to the Federal Energy Regulatory Commission (FERC) because we must evaluate the effects of 

turbine entrainment on fish populations. We must decide, with assistance from resource 

agencies, whether to require licensees to take protective measures to reduce entrainment. 

The purpose of the report is to use recent entrainment studies to identify trends that 

might, in some cases, reduce the need for site-specific entrainment studies. The entrainment 

studies reviewed also provide a basis to suggest methods of improving future studies. Costs and 

effectiveness of alternatives to reduce entrainment provide aquatic resource protection options. 

The report focuses on entrainment studies east of the Mississippi River because more 

studies are available for this area. Information on protective measures includes sites from the 

entire country. 

This report provides guidance to Division of Project Review staff in their review of 

applications for hydropower licenses. It is also valuable to resource agencies and hydropower 

licensees/applicants. We remind the reader that this is a preliminary summary assessment, and 

new information may alter the suggestions presented here. 

Acting 

John H. 

Director, 

Clements 

Division of Project Review 

d~., Director, Office of Hydropower Licensing 

Fish Entrainment at Hydropower Projects Page i 
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Acknowledgements 

The Office of Hydropower Licensing, Federal Energy Regulatory Commission (FERC), 

thanks Douglas Hjorth, Fred Winchell, John Downing, Don Cochrane, and Rose Perry from 

Stone & Webster Environmental Technology & Services for their contributions to this 

publication. We also offer· sincere appreciation to the members of the Entrainment Review 

Team listed in Table 2-1 on page 2-2. They provided many useful suggestions that improved 

this report. Special thanks are also extended to Glenn Cada (Oak Ridge National Laboratory), 

and Jim Francfort (Idaho National Engineering Laboratory). 

Fish Entrainment at Hydropower Projects Page iii 
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EXECUTIVE SUMMARY 

Fish entrainment at hydropower 

projects and its impacts are a concern in 

many parts of the country. The Electric 

Consumers Protection Act of 1986 

(ECPA) requires the Federal Energy 

Regulatory Commission (FERC) to 

consider power and non-power values 

when licensing nonfederal hydropower 

projects. Entrainment of large numbers of 

fish at projects sometimes has an adverse 

impact on fishery resources and protective 

measures are required. Consequently, 

resource agencies frequently recommend 

entrainment studies during prefiling 

consultations with applicants seeking new 

or original licenses. FERC often requires 

entrainment studies through "Additional 

Information Requests" (AIRs) after the 

license application is filed or as a 

condition of the license issued. Over the 

last 5 years, many entrainment studies 

have been conducted, generally coinciding 

with ECP A and the expiration of an 

unusually large number of existing licenses 

in 1993. Costs associated with entrainment 

studies or protective measures can be 

prohibitive, however, and may adversely 

affect the power values of hydropower 

projects. 

The primary purpose of this 

document is to gather and summarize data 

from recently conducted entrainment 

studies. This document will be a resource 

to FERC staff during review of 

hydropower applications but also will have 

value for resource agencies and 

hydropower licensees/applicants. It is not 

intended to be a FERC policy document. 

The impact of entrainment depends on 

site-specific physical and biological factors 

and resource management objectives. 

Because each site is unique, FERC staff 

Fish Entrainment at Hydropower Projects 

will continue to assess entrainment 

impacts on a case-by-case basis. 

Parameters included in the 

database were determined by FERC, 

Stone & Webster, and an Entrainment 

Review Team comprising hydropower 

licensees/applicants and agency 

representatives. We collected cost 

information about entrainment studies and 

protective measures using a questionnaire 

sent to licensees of 157 projects with 

licenses expiring in 1993. We 

supplemented information from the 

questionnaire with information from other 

sources. 

We included 45 studies in the 

entrainment database, all from sites east 

of the Mississippi. West coast hydropower 

project operators often are required to 

install protective measures without 

entrainment studies, especially at plants on 

rivers with anadromous fish runs. 

The electrical capacity of sites in 

the database ranged from 0.56 to 102 

MW, and most were below 5 MW. 

Hydraulic capacity of sites was 360 to 

35,598 cfs, and most sites were below 

3,000 cfs. 

Study results are as follows: 

• There is tremendous 

variability in the collection 

and analytical procedures 

used in entrainment studies, 

which greatly limits 

comparability of 

entrainment data from site 

to site. This variability is a 

function of the site-specific 

constraints, costs, differing 

Pagev 
• 

• 

• 

• 

Page vi 

resource agency objectives, 

and the presence of 

precedents and other 

guidance for conducting 

studies. For this reason, it 

was difficult to draw many 

conclusions from this 

database. 

To determine whether or 

not differences in 

entrainment rates between 

sites are due to biological or 

physical (e.g., plant design) 

factors, collection 

techniques and analytical 

methods for future 

entrainment studies must be 

standardized. 

Flow-adjusted entrainment 

rates (all species and sizes 

combined) for projects on 

the same river are generally 

within 2-3 fold of each 

other. 

Most entrained fish are 

small. 

Entrainment results show 

extreme variability in diel, 

seasonal, spatial, sitespecific and species-specific 

patterns. Total entrainment 

rates (species and sizes 

combined) ranged from a 

low of 0.6 fish/hour to 2,492 

fish/hour. Data support the 

episodic nature of 

entrainment but suggest that 

the dominant species in the 

entrainment catch at a given 

site generally remains the 

same, with some year to 

year variability. 

• 

• 

• 

• 

• 

Some entrainment patterns 

were related to intake 

configuration. Sampling 

nearshore intakes or near 

walls generally yielded 

higher entrainment rates. 

For intakes oriented parallel 

to prevailing flow, center 

intakes have the lowest 

entraiilQlent rates, and 

downstream intakes 

generally the highest. 

Downstream sites on a river 

generally entrain more fish. 

Quantitative statistical 

analysis of total entrainment 

rates revealed no consistent 

significant trends relative to 

physical factors analyzed in 

this report. 

Extrapolating total 

entrainment rates (all 

species and sizes combined) 

from sampled sites to 

unsampled sites may yield 

more precision m some 

basins and for some species. 

Site-specific entrainment 

studies may yield more 

precision at sites that are 

dissimilar in site 

characteristics or species 

composition. 

Cost of conducting 

entrainment studies is 

generally high. Costs 

associated with installing 

protective measures, 

however, are generally 

higher and may affect a 

project's economic viability. 

Netting studies consistently 

Fish Entrainment at Hydropower Projects 
cost more than 

hydroacoustic studies. 

• All of the protective 

measures that have been 

used to reduce entrainment 

have limitations, and few 

are highly effective for a 

wide range of sizes and 

species of fish. Low-velocity 

screening systems, such as 

those used in the Pacific 

Northwest to protect 

anadromous fish, are 

reasonably well-proven but 

are costly to install and 

operate. More data are 

required for other systems 

(e.g., high-velocity screening 

systems, angled bar racks, 

louvers, barrier nets, and/ or 

behavioral barriers such as 

strobe lights and sound) to 

document their effectiveness 

under a range of site and 

operating conditions. 

• Guidelines suggested in this 

report are intended to aid 

in standardizing future 

entrainment sampling and 

reporting protocols. 

However, assessment of the 

need for studies, as well as 

the actual study design, is 

based on a number of 

factors, including the 

expected level of impact 

and the cost of the studies. 

Further iterations of these 

guidelines will be needed as 

additional information 

becomes available. 

Fish Entrainment at Hydropower Projects Page vii 
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CONTENTS 

•VOLUME 1 • 

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v 

1.0 INTRODUCfiON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 

1.1 Need for this Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 

1.2 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 

2.0 METHODS ................................................. 2-1 

2.1 Establishment of the Entrainment Review Team . . . . . . . . . . . . . . . . 2-1 

2.2 Derivation of the Entrainment Database . . . . . . . . . . . . . . . . . . . . . . 2-1 

2.3 Development of the Entrainment Protective Measure Cost 

and Effectiveness Questionnaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 

2.4 Analytical Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6 

2.4.1 Qualitative Trend Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6 

2.4.2 Quantitative Trend Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7 

2.4.3 Rationale for Selecting Representative Species . . . . . . . . . . . . 2-7 

3.0 RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 

3.1 Geographical Distribution of Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 

3.2 Database Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 

3.2.1 General Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 

3.2.2 Comparison of Different Sampling Techniques ............ 3-14 

3.2.3 Relative Entrainment Between Units and Influence of Intake 

Configuration on Entrainment Rates .................... 3-16 

3.2.4 Horizontal and Vertical Distribution Within Units .......... 3-20 

3.2.5 Quantitative Trend Analysis .......................... 3-21 

3.2.6 Analysis of Monthly Trends of Representative Species ....... 3-27 

3.2.7 Size Composition Assessment ......................... 3-43 

3.3 Comparison of Entrainment to Reservoir Populations ............ 3-48 

3.4 Summary of Entrainment Protective Measure Questionnaire Results . 3-57 

3.4.1 Summary of Cost Information on Entrainment 

and Turbine Mortality Studies ......................... 3-57 

3.4.2 Summary of Cost Information on Recommended 

Entrainment Protective Measures ...................... 3-59 

4.0 DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 

4.1 Extrapolation of Entrainment Data . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 

4.2 Cost and Effectiveness of Protective Measures . . . . . . . . . . . . . . . . . . 4-2 

4.2.1 Low-Velocity Fish Screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3 

Fish Entrainment at Hydropower Projects Page ix 
4.2.2 High-Velocity Fish Screens ......................... 4-4 

4.2.3 Fish Bypasses at Existing Trashracks ................... 4-6 

4.2.4 Close-Spaced and Angled Bar Racks ................... 4-7 

4.2.5 l..ouvers ........................ ; ............ 4-8 

4.2.6 Barrier Nets ................................. 4-10 

4.2. 7 Behavioral Barriers ............................. 4-10 

4.3 Entrainment Rates Relative to Impoundment Populations .......... 4-12 

4.4 Suggested Guidelines for Determining the Need for Entrainment 

Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13 

4.5 Suggested Guidelines for Conducting Entrainment Studies .......... 4-15 

4.5.1 Guidelines for Netting Studies ...................... 4-17 

4.5.2 Guidelines for Hydroacoustic Studies .................. 4-25 

4.5.3 Guidelines for Reporting Entrainment Study Results ......... 4-28 

5.0 CONCLUSIONS ........................................ 5-l 

6.0 LITERATIJRE CITED .................................... 6-1 

6.1 Literature Cited in the Interpretive Report . . . . . . . . . . . . . . . . . . . . 6-1 

6. 2 Entrainment Study Reports Included in the Database . . . . . . . . . . . . . . 6-5 

• VOLUME 2 • 

Appendix 1. Listing of Sites Considered for Inclusion in the Database . . . . . . . . . . Al-l 

Appendix 2. Explanation of Data Fields ............................. A2-1 

Appendix 3. Entrainment Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A3-1 

3.1 Numerical Portion of Database . . . . . . . . . . . . . . . . . . . . A3 .1-1 

3.2 Narrative Portion of Database . . . . . . . . . . . . . . . . . . . . A3.2-1 

Appendix 4. Detailed Statistical Results and Plots of Exploratory Regression 

Analyses ........................................ A4-1 

Appendix 5. Detailed Statistical Results of Supplemental Statistical Analyses . . . . . . A5-1 

Pagex Fish Entrainment at Hydropower Projects 
LIST OF FIGURES 

Figure 2-1 Cost Questionnaire: Entrainment Abundance Studies, Turbine 

Mortality Studies and Protective Measures ..................... 2-45 

Figure 3-1 Location of Projects Included in Entrainment Database . . . . . . . . . . . 3-2 

Figure 3-2 Distribution of Sites by State Included in the Entrainment Database . 3-3 

Figure 3-3 Electrical Capacity of Sites Included in the Entrainment Database . . . 3-4 

Figure 3-4 Hydraulic Capacity of Sites Included in the Entrainment Database . . . 3-4 

Figure 3-5 Millville Monthly Fish Entrainment for 1986, 1989, 1990 and 1991 ... 3-12 

Figure 3-6 Smallmouth Bass Entrainment at Michigan Sites ................ 3-28 

Figure 3-7 Smallmouth Bass Entrainment at Wisconsin Sites ................ 3-30 

Figure 3-8 Walleye Entrainment at Michigan Sites ....................... 3-31 

Figure 3-9 Walleye Entrainment at Wisconsin Sites ...................... 3-32 

Figure 3-10 Black Crappie Entrainment at Michigan Sites .................. 3-34 

Figure 3-11 Black Crappie Entrainment at Wisconsin Sites .................. 3-35 

Figure 3-12 Black Crappie Entrainment at South Carolina Sites .............. 3-36 

Figure 3-13 Yellow Perch Entrainment at Michigan Sites ................... 3-38 

Figure 3-14 Yellow Perch Entrainment at Wisconsin Sites .................. 3-39 

Figure 3-15 Yellow Perch Entrainment at South Carolina Sites ............... 3-40 

Figure 3-16 White Sucker Entrainment at Michigan Sites ................... 3-41 

Figure 3-17 White Sucker Entrainment at Wisconsin Sites .................. 3-42 

Figure 3-18 Gizzard Shad Entrainment at Midwestern Sites and West Virginia ... 3-44 

Figure 3-19 Gizzard Shad Entrainment at Southeastern Sites (Georgia and 

South Carolina) ......................................... 3-45 

Figure 3-20 Threadfin Shad Entrainment at Southeastern Sites (Georgia and 

South Carolina) ......................................... 3-46 

Fish Entrainment at Hydropower Projects Page xi 
LIST OF TABLES 

Table 2-1 Entrainment Review Team 2-2 

Table 3-1 Annual Entrainment Rates by River and State . . . . . . . . . . . . . . . . . . 3-7 

Table 3-2 Relative Abundance of Entrained Fish Collected at Millville 

From 1986 to 1991 ...................................... 3-11 

Table 3-3 Year-to-Year Variability in Total Monthly Entrainment Rates at 

Sites Included in the Database .............................. 3-13 

Table 3-4 Comparison of Total Annual Entrainment Rates Derived by 

Hydroacoustic and Netting Techniques ....................... 3-17 

Table 3-5 Predominant Size of Entrained Fish at Sites Included in the Database 3-47 

Table 3-6 Relative Abundance of Dominant Species Collected in Impoundments 

Compared to Entrained Fish at Projects on the Au Sable River, 

Michigan .............................................. 3-50 

Table 3-7 Relative Abundance of Dominant Species Collected in Impoundments 

Compared to Entrained Fish at Projects on the Muskegon River, 

Michigan .............................................. 3-51 

Table 3-8 Relative Abundance of Dominant Species Collected in Impoundments 

Compared to Entrained Fish at Miscellaneous Projects in Michigan 

and Wisconsin .......................................... 3-52 

Table 3-9 Relative Abundance of Dominant Species Collected in Impoundments 

Compared to Entrained Fish at Miscellaneous Projects in Ohio 

and Georgia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-54 

Table 3-10 Population Estimates of Target Species Compared to Annual 

Entrainment of Those Species .............................. 3-55 

Table 3-11 Entrainment and Turbine Mortality Study Cost Summary .......... 3-58 

Table 3-12 Actual Costs Associated With Installation of Protective Measures 

Designed to Minimize Entrainment .......................... 3-61 

Table 3-13 Conceptual Costs Associated With Installation of Protective 

Measures Designed to Minimize Entrainment .................. 3-67 

Table 3-14 Summary of Actual Costs Associated With Installation of 

Entrainment Protective Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-72 

Page xii Fish Entrainment at Hydropower Projects 
Table 3-15 Summary of Conceptual Costs Associated With Installation of 

Entrainment Protective Measures . . . . . . . . . . . . . . . . . . . . . . . . . 3-73 

Table 3-16 Range of Design and Construction Costs Associated With Specific 

Entrainment Protective Measures ......................... 3-74 

Table 4-1 1991 Millville Entrainment Data Used to Evaluate the Error 

Associated with Sampling Three Days Per Month (Consecutive 

or Independent) ................................... 4-24 

Fish Entrainment at Hydropower Projects Page xiii 
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PRELIMINARY ASSESSMENT OF FISH ENTRAINMENT AT HYDROPOWER 

PROJECTS -A REPORT ON STUDIES AND PROTECTIVE MEASURES 

1.0 INTRODUCTION 

1.1 Need for this Report 

The Federal Energy Regulatory 

Commission (FERC or Commission) 

considers protective measures for 

"identifiable environmental impacts" in the 

licenses it issues for nonfederal 

hydropower projects. The Electric 

Consumers Protection Act of 1986 

requires FERC to balance power and 

nonpower values associated with 

hydroelectric development. 

During consultation, resource 

agencies often request site-specific 

entrainment and turbine mortality studies 

to help quantify non-power values of 

affected fishery resources. Entrainment is 

the passage of organisms through water 

intakes. At hydroelectric projects, fish and 

other aquatic organisms frequently are 

drawn into turbine intakes where they may 

be injured or killed. Various life-stages of 

anadromous and resident fish may be 

entrained. 

Since 1986 an increasing number of 

entrainment studies have been requested 

and conducted. Entrainment studies may 

not be needed, however, if existing data 

indicate that adverse impact is low or 

installing protective measures without 

studies is more cost-effective. 

This report presents data from 

completed entrainment studies and draws 

inferences from these data, where 

possible. Licensees/applicants use many 

different approaches to study entrainment. 

These approaches often reflect differences 

in resource agency and/or consultant 

Fish Entrainment at Hydropower Projects 

guidance. Costs of studies also impact the 

level of study that a licensee/applicant 

provides. Because of the many different 

approaches to address entrainment issues, 

we recommend establishing a standard 

protocol for conducting entrainment 

studies. This document provides 

guidelines for building a standard 

protocol. However, assessment of the 

need for studies, as well as the actual 

study design, is based on a number of 

factors, including the expected level of 

impact and the cost of the studies. 

Because resolution of entrainment 

issues is an ongoing iterative process, the 

database developed for this report can 

accommodate new data from future 

studies. This report addresses difficulties 

of data comparability. 

1.2 Objectives 

The objectives of this document, in 

descending priority, are as follows: 

• summarize existing studies 

and analyze data to identify 

trends; 

• assess the methods to use in 

future studies that address 

entrainment and protective 

measures; and 

• evaluate the costs and 

effectiveness of commonly 

requested protective 

measures for reducing 

entrainment losses. 

Page 1-1 
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2.0 

2.1 

METHODS 

Establishment of the Entrainment 

Review Team 

Stone & Webster (SWEC) 

assembled an Entrainment Review Team 

(ERT) to provide guidance on the status 

and future of entrainment studies 

throughout the United States. Based on 

the location of sites where entrainment 

studies have been conducted, identified by 

PERC (Appendix 1 ), we invited 

representatives of the U.S. Fish and 

Wildlife Service (USFWS) regions and 

state fish and wildlife agencies where most 

of the entrainment studies have been 

conducted to participate on the ERT. 

SWEC also contacted utility 

organizations, including the Edison 

Electric Institute (EEl), the Electric 

Power Research Institute (EPRI), the 

National Hydropower Association (NHA), 

and the Wisconsin-Michigan Hydro Users 

Group (HUG). Numerous utility 

representatives from these organizations 

responded to our invitation. 

Two groups that commonly 

intervene in hydroelectric licensing 

proceedings, American Rivers and Trout 

Unlimited, were invited to participate, but 

failed to respond to the invitation. 

SWEC organized two 

teleconferences (February 1 and 2, 1993) 

to explain the objectives of the project, 

solicit input from participants, and identify 

ERT members. Teleconference 

participants identified additional 

individuals to add to the mailing list to 

expedite the agency review process. As a 

result of the teleconference, we decided to 

include all individuals directly expressing 

an interest in participating or that were 

added to the project mailing list; this 

Fish Entrainment at Hydropower Projects 

resulted in a large ERT (Table 2-1) but 

one that did not exclude any interest 

groups. 

We asked ERT members to: 1) 

provide input on the content of the 

entrainment database, 2) review the draft 

database and provide comments on 

specific projects with which they were 

familiar, and 3) comment on the content 

of the draft interpretive report. 

The U.S. Department of Energy 

(DOE) published a study comparing the 

cost-effectiveness of entrainment 

protective measures (Francfort et al., 

1994). This DOE report should be used 

in conjunction with our report by those 

parties involved in evaluating the need for, 

or scoping entrainment studies at specific 

hydropower sites. 

2.2 Derivation of the Entrainment 

Database 

PERC staff compiled a list of all 

projects at which entrainment studies may 

have been performed. After an internal 

screening, 21 projects were eliminated 

from further consideration. We then 

evaluated the remaining 85 projects (Appendix 1) according to project objectives. 

FERC provided SWEC with 

available entrainment study reports. 

When the study reports were not available 

from FERC, we contacted licensees, asked 

whether or not entrainment studies had 

been conducted at their project(s) and 

requested copies of the entrainment 

reports. Additional recently completed 

entrainment studies at Pixley, Upper and 

Lower projects were forwarded by FERC 

staff to SWEC as they were received. The 

ERT also identified pertinent entrainment 

studies that were not included in the 

Appendix 1 list. 

Page 2-1 
TABLE 2-1 

ENTRAINMENT REVIEW TEAM 

Name Entity Represented Name Entity Represented 

Federal Agency Represellllltives 

Alex Hoar USFWS (MA) John Warner USFWS (NH) 

Ben Rizzo USFWS (MA) Hilary Zich USFWS {PA) 

Dave Bryson USFWS (NY) Rob Kelsey USFWS (MD) 

Gordon Russell USFWS (ME) Chris Clower USFWS (WV) 

Steve Gilbert USFWS (SC) Bob Krska USFWS (MN) 

Larry Obomy USFWS (WI) John Hamilton USFWS (MI) 

Don Sundeen USFWS (OR) Rich Greenwood USFWS (MI) 

Jennifer Hill FERC (DC) Jim Lynch FERC (DC) 

John Ramer FERC (DC) 

Sklte Agency Represellllltives 

Mark Woythal NY Dept. Env. Cons. Gary Whelan MIDNR 

Ed Radle NY Dept. Env. Cons. Walt Houghton MIDNR 

Jim Rawson WVDNR Tom Tbuemler WIDNR 

Leroy Young PA Fish & Boat Com. Karl Sheidegger WIDNR 

Wayne Davis KY Dept. Fish & Wildlife Will Reid Idaho Fish & Game Dept. 

Gerrit Jobsis SC Wildlife and Marine Resources 

Dept. 

Utility Represellllltives 

Bob Richter Central Maine Power Co. (EEl) Linda Hinseth Wisconsin Power & Light 

Co. (EEl) 

Keith Comeau Adirondack Hydro Dev. Corp. (EEl) Dave Michaud Wisconsin Power & Light 

Co. (HUG) 

John Sulaway New York Power Authority {EEl) Tony Maio EEl 

Tom Tatham New York Power Authority (EEl) Lowell Neudahl Minnesota Power (EEl) 

Kevin McGrath New York Power Authority (EEl) Alan Gaulke Am. Elect. Power Service 

Corp. (EEl) 

Gary Niagara Mohawk Power Corp. (EEl) Bruce Eddy Pacific Corp. (EEl) 

Schoonmacker 

Dave Fingada Rochester Gas & Electric (EEl) Brian McGurty So. Calif. Edison Co. 

(EEl) 

John Crutchfield Carolina Power & Light Co. (EEl) Tom Jareb Pacific Gas & Electric 

Co. (EEl) 

George Galleher Duke Power Co. (EEl) Jack Mattice Electric Power Research 

Institute 

Charles Sullivan Electric Power Research Institute 

AdditioiUil Experts 

Glenn Cada Oak Ridge National Lab. 

Page 2-2 Fish Entrainment at Hydropower Projects 
We evaluated . all available study 

reports for inclusion in the database. In 

general, we included studies if the 

sampling effort was sufficient to ensure a 

reasonable level of confidence in the 

entrainment estimate derived from the 

data. We did not include sites that were 

geographically isolated (e.g., Mokelumne 

and Elwha) or involved pumped storage 

(e.g., Big Creek No. 8 & 2A) because data 

from these sites were not considered to be 

comparable to data from other sites due 

to species and operational differences. 

Appendix 1 describes the rationale for not 

including a report in the database. 

The parameters for the database 

were established in the original task 

description and supplemented by SWEC 

and the ERT. Tables in the database 

contain variables that can be quantitatively 

analyzed. Variables that require 

qualitative comparisons are included in 

the narrative part. 

Data extracted from the 

entrainment reports were supplemented by 

information contained in license 

application documents or other sources 

such as U.S. Geological Survey Water 

Yearbooks. We converted entrainment 

information for each site to a standard 

unit of measure: number of fish per hour. 

We also included the total annual number 

of fish entrained at each site. Appendix 2 

contains a detailed description of each 

data field in the tabular portion of the 

database. 

We sent draft databases, with 

copies of calculation sheets showing the 

sources of information, to the project 

licensee/applicant and members of the 

ERT. We asked licensees/applicants to 

verify the accuracy of the database entries, 

review the appropriateness of assumptions 

made to convert entrainment data to the 

Fish Entrainment at Hydropower Projects 

standardized format, and provide data for 

any blank fields. We asked ERT 

members to comment on the adequacy of 

the studies and to review the assumptions 

made in deriving the data. In some cases, 

both the licensee and an ERT member 

provided blank field information. When 

the information conflicted, we assumed 

the licensee's information was the most 

accurate. The narrative portion of the 

database contains comments on each 

study. 

2.3 Development of the Entrainment 

Protective Measure Cost and 

Effectiveness Questionnaire 

SWEC developed a questionnaire 

to collect information on the costs of 

conducting entrainment studies and 

implementing protective measures and the 

effectiveness of installed protective 

measures. Although we did not duplicate 

previous work such as that performed by 

DOE (Sale et al., 1991) some overlap 

between this study and previous studies is 

unavoidable. 

We asked the Idaho National 

Engineering Laboratory (INEL), which 

previously solicited information by 

questionnaire on the cost of entrainment 

and turbine mortality studies and 

protective measures for the DOE study, to 

review our questionnaire. We 

incorporated INEL's and FERC's 

suggestions into our final questionnaire 

(Figure 2-1). 

SWEC mailed the questionnaire to 

licensees/applicants of the 157 projects 

scheduled to be relicensed by the end of 

1993. We selected these licensees because 

many of them had conducted entrainment 

studies as recommended by resource 

agencies during the consultation process. 

We were able to assemble entrainment 

Page 2-3 
Figure 2-1 

COST QUESTIONNAIRE: ENTRAINMENT ABUNDANCE STUDIES, 

TURBINE MORTALITY STUDIES AND PROTECTIVE MEASURES 

PROJECT NAME __________________________ _ 

FERC NO. ____________________________ __ 

RETURN TO: 

Douglas Hjorth 

Stone & Webster Env. 

Services 

245 Summer St. 

Boston, MA 02210 

ENTRAINMENT ABUNDANCE AND TURBINE MORTALITY STUDIES 

COSTS OF ENTRAINMENT ABUNDANCE STUDIES (separate hydroacoustic 

and netting costs, if possible) 

COSTS OF TURBINE MORTALITY STUDIES (indicate basic sampling mode, 

e.g., tailrace netting) __________________________________________ _ 

TIME SPAN OF ENTRAINMENT STUDIES 

ENTRAINMENT PROTECTIVE MEASURES (installed or costs estimated) 

YEAR PROTECTIVE MEASURE INSTALLED __________________ , OR YEAR 

COSTS ESTIMATED 

ENTRAINMENT PROTECTIVE MEASURES (e.g., travelling screens, 

slotted screens, fish bypass systems, angled bar racks, inclined 

screens, barrier nets, spill flows, attractant and repellant measures) ________________________________________________________ __ 

DESCRIPTION OF PROTECTIVE MEASURES (attach additional sheets if needed) __________________________________________________________ __ 

IS PROTECTIVE MEASURE INTENDED ONLY TO EXCLUDE FISH FROM TURBINE 

PASSAGE OR ALSO TO FACILITATE PASSAGE? (indicate which) 

MAXIMUM FLOW CAPACITY (CFS) OF UNIT(S) WITH PROTECTIVE DEVICES 

Page 2-4 Fish Entrainment at Hydropower Projects 
Figure 2-1 (Continued) 

DESIGN APPROACH VELOCITY (FPS) PERPENDICULAR TO SCREEN (if applicable) ____________________________________________________ __ 

COSTS OF ENGINEERING DESIGN FOR ENTRAINMENT PROTECTIVE MEASURES 

YEAR(S) IN WHICH ENGINEERING DESIGN COSTS INCURRED ____________ ___ 

COSTS OF CONSTRUCTING ENTRAINMENT PROTECTIVE MEASURES 

YEAR(S) IN WHICH CONSTRUCTION COSTS INCURRED __________________ __ 

ANNUAL OPERATION AND MAINTENANCE COSTS (indicate the year that 

such costs were derived,also) 

ANNUAL COSTS OF LOST GENERATION ATTRIBUTABLE TO PROTECTIVE DEVICE 

(include the basis for the costs) ______________________________ __ 

ANNUAL COSTS OF FOLLOW-UP ENTRAINMENT MONITORING STUDIES AND 

ASSOCIATED REPORTING REQUIREMENTS 

YEAR(S) IN WHICH ENTRAINMENT MONITORING STUDIES WERE CONDUCTED OR 

ARE PROPOSED ----------------------------------------------------

EFFECTIVENESS OF THE PROTECTIVE MEASURE AND BASIS FOR DETERMINING 

EFFECTIVENESS (cite reports, if possible) 

LIST ANY OTHER COST ELEMENTS ASSOCIATED WITH THE INSTALLED 

PROTECTIVE MEASURE ---------------------------------------------

NAME, TITLE AND TELEPHONE NUMBER OF PERSON FILLING OUT 

QUESTIONNAIRE---------------------------------------------------

COMMENTS: 

Fish Entrainment at Hydropower Projects Page 2-5 
and turbine mortality costs for studies 

conducted during the last several years. 

Costs for potentially recommended 

protective measures also were likely to 

have been developed by many applicants 

where entrainment mortality was 

considered to be high. The DOE study 

(Sale et al., 1991) presented costs for 

many studies and protective measures 

implemented between 1980 and 1990. We 

expected the responses to our 

questionnaire to reflect most recent costs 

available and to be useful in providing 

guidance for implementing future studies 

and/ or protective measures. 

Distributing the questionnaire only 

to those licensees with expiring licenses 

did not provide a substantial amount of 

new information on the effectiveness of 

installed entrainment protective measures, 

since most projects scheduled to be 

relicensed would not normally install 

protective measures until after the license 

was issued. DOE conducted a detailed 

study on the cost-effectiveness of many 

conventional entrainment protective 

measures, however, as a follow-up to its 

1991 report. The DOE study (Francfort 

et al., 1994) obviates the need to generate 

a similar analysis as part of our study. 

2.4 Analytical Approach 

2.4.1 Qualitative Trend Analysis 

Certain variables in the database 

are not amenable to statistical analysis. 

For example, nearly all intakes of the 

studied hydropower projects are oriented 

perpendicular to the flow of the river; only 

three intakes are oriented parallel to the 

direction of flow. Consequently, the trend 

analysis for this variable consists of a 

qualitative assessment of entrainment 

patterns at these three sites and how they 

Page 2-6 

differ from sites with perpendicular 

oriented intakes. 

Because of variable sampling and 

reporting conventions, it is difficult to 

make quantitative intersite comparisons. 

The size composition of entrained fish is 

a good example of such variability. The 

minimum size detected by hydroacoustic 

methods varies between sites and often at 

the same site for different plant operating 

conditions. The minimum size captured in 

nets also varies across studies. In 

addition, the size of fish collected by nets 

is sometimes reported as a species-specific 

length range, by size intervals of the total 

number of fish collected, or as tables of 

individual measurements of each fish 

collected. 

Generalizations about the size of 

entrained fish at different sites are 

possible and are included in this report. 

More rigorous statistical treatment of 

these data is not possible, however, 

without standardized reporting of lengthfrequency data. Additional variables that 

were evaluated for trends qualitatively, for 

reasons similar to those described above, 

include the number of units sampled, the 

proportion of total flow sampled, the study 

method used (netting or hydroacoustics), 

and the relative entrainment rates 

between units. 

The specific type of analyses 

conducted depended on the availability of 

pertinent information in the database and 

individual study reports. When possible, 

we prepared a comparative table. and 

evaluated the data for the presence of 

consistent trends for our qualitative 

assessment. If a trend was evident, we 

reviewed the database for factors that 

were common to those sites exhibiting 

similar trends. If an entrainment study at 

a specific site provides useful insight into 

Fish Entrainment at Hydropower Projects 
a factor that could influence entrainment 

rates at other sites, we describe the salient 

findings of the study. 

2.4.2 Quantitative Trend Analysis 

We conducted quantitative analysis 

of entrainment data in two parts: an 

exploratory regression analysis, which 

included an evaluation of the effect of 

individual, high leverage data points; and 

a supplemental analyses, which included 

these high leverage data points. We 

examined potential relationships between 

physical site parameters and the total 

entrainment rate (for all species and sizes 

combined) in both sets of analyses. We 

did not perform species- and size-specific 

statistical analyses because of the limited 

number of studies that provided estimates 

of total entrainment rates by species and 

size collected in a comparable manner. 

We did group and analyze sites as a block, 

however, if they had similar species 

assemblages of entrained fish. We performed all analyses for two entrainment 

variables: the average annual entrainment 

rate (fish per hour) and the flow-adjusted 

rate (fish per hour per 1,000 cfs of plant 

capacity). 

We conducted the exploratory 

regression analysis using Version 2 of JMP 

(SAS, 1989); the "Fit Y by X" platform in 

JMP fit both linear and quadratic lines for 

each variable. We examined plots of each 

regression to identify individual high 

leverage data points that cause or mask a 

significant association. The high leverage 

points were typically from sites with 

exceptionally high rates of entrainment or 

where the value of the particular site 

variable was substantially different from 

all other sites. We examined the effect of 

any outlier data points by removing them 

from the data set and evaluating changes 

in the significance of the regressions. 

Fish Entrainment at Hydropower Projects 

We performed each exploratory 

regression on the following data sets: 

1) all available data; 

2) all available data excluding sites 

dominated by clupeids; 

3) only sites employing full-flow 

tailrace nets (also excluding sites 

dominated by clupeids ); and 

4) individual watersheds where data 

were available from two or more 

sites. 

Our supplemental analyses included 

a correlation analysis, a principal 

components analysis, and a regression 

analysis using species assemblages as a 

covariate. 

We performed the correlation 

analysis using the JMP (SAS, 1989) 

analysis platform "Y's by Y's" to calculate 

the Pearson product moment correlation 

and scatterplot matrices. We used the 

JMP analysis platform "Spin" to conduct 

the principal components analysis. We 

used the JMP analysis platform "Select 

Model" to perform the regression analysis 

using species assemblage as a covariate. 

In this last analysis, we grouped sites into 

assemblage categories based on the 

predominant groups of species represented 

in entrainment samples. 

2.4.3 R a t i o n a I e f o r S e I e c ti n g 

Representative Species 

Comparisons of entrainment for all 

species may mask trends associated with 

individual species. Because a comparison 

of entrainment rates for all species 

included in the database was impractical, 

however, we selected representative 

species to evaluate entrainment rates of 

important sportfish and forage fish in 

addition to the total entrainment rate. 

We did not group representative species 

Page 2-7 
for this analysis (i.e., centrarchids, 

cyprinids, percids) because each species 

has unique habitat requirements and 

behavioral characteristics. We evaluated 

monthly entrainment rates of these representative species to identify trends over 

time. 

We selected smallmouth bass and 

walleye as representative sportfish. Both 

species were entrained at many sites in 

Michigan and Wisconsin, where the 

majority of studies in the database were 

conducted. Sufficient data were available 

to indicate whether or not there were 

trends in entrainment rates. 

We selected black crappie and 

yellow perch as representative panfish. 

Both species are often sought by anglers 

and are an important recreational fishery 

resource. They also are both common at 

sites in the midwest and the southeast, 

which gives a broader geographic analysis 

of entrainment rates than is possible for 

smallmouth bass or walleye. 

SWEC selected white sucker and 

two species of clupeids as representative 

forage fish. White suckers were collected 

often enough in entrainment samples in 

Michigan and Wisconsin to enable 

potential trends to be identified. This 

species has a wide geographical range, 

and, if trends were apparent at the sites in 

the database, the pattern may be 

appropriate to explore at sites not 

included in the database. 

Clupeids are an abundant forage 

base in certain parts of the country and, in 

many cases, habitat preference and 

behavioral patterns among species are 

similar. The two species of clupeids with 

sufficient entrainment data in the database 

are gizzard shad and threadfin shad. 

Entrainment trends of these two species 

Page 2-8 

may provide insight into entrainment 

trends of other clupeids throughout the 

country. 

Fish Entrainment at Hydropower Projects 
3.0 RESULTS 

3.1 Geographical Distribution of Sites 

All of the studies included in the 

entrainment database were conducted at sites 

east of the Mississippi River (Figure 3-1). 

Hydroelectric projects west of the 

Mississippi (in California, Oregon, 

Washington, and Idaho) often install screens 

with bypass facilities (especially at sites with 

anadromous fish), which minimizes the need 

to conduct entrainment studies (personal 

communication, letter from Gerry Jackson, 

Acting Regional Director, USFWS, to 

Douglas Hjorth, SWEC, dated April 16, 

1993). Most sites (24 of 45) are within the 

Great Lakes drainage, nine sites each are 

within the Upper Mississippi and MidAtlantic Coastal drainages, and four sites are 

within the Upper Ohio River drainage. 

The greatest number of projects in the 

database (18) are in Michigan, followed by 

Wisconsin (12), and South Carolina (6) 

(Figure 3-2). Resource agencies in these 

states often recommend site-specific 

entrainment studies. 

3.2 Database Analysis 

3.2 .1 General Findings 

The database includes results from 

entrainment studies at 45 sites. Most studies 

were conducted at hydropower projects with 

an electrical capacity of less than 5. 0 MW 

(Figure 3-3), but electrical capacity ranges 

from 0.56 MW (Tower) to 102 MW (Hawks 

Nest). Hydraulic capacities range from 360 

cfs (Tower) to 35,598 cfs (Greenup Lock 

and Dam); the capacity at most sites is less 

than 3,000 cfs (Figure 3-4). 

Fish Entrainment at Hydropower Projects 

Entrainment Study Methods 

The database's most striking 

characteristic is the variability in 

methodologies. Hydroacoustic studies, 

which varied both in the number of units 

sampled and in the proportion of the flow 

sampled at each unit, often were designed to 

be supplemented by netting studies. In one 

case (Crowley) hydroacoustic estimates 

supplemented tailrace netting collections. 

Frequently, both netting and hydroacoustic 

techniques were used, and the most 

appropriate estimate was determined at the 

end of the study. Although approaches 

differed, all study plans were developed in 

consultation with, and in most cases 

approved by, state and federal resource 

agencies. 

Netting entrainment was estimated by 

using partial-flow tailrace nets, partial-flow 

turbine gallery nets, partial-flow forebay 

nets, full-flow tailrace nets, and 

combinations of partial and full-flow nets 

that varied either spatially or over time. 

The number of units sampled by nets ranged 

from 10 percent to 100 percent of the units. 

Netting effort was extremely variable, 

ranging from a low of 8 hours per month at 

Lock and Dam #2 to a high of 720 hours 

per month at Youghiogheny. Sampling 

efforts varied between sites, and in some 

cases, at the same site (e.g., monthly 

sampling efforts at Millville ranged from 24 

to 589 hours). 

At some sites there were no net 

efficiency studies, most often because net 

collections were designed to provide species 

and size composition data to support 

hydroacoustic sampling. Various 

approaches were used for net efficiency 

studies. At some sites, net efficiency was 

Page 3-1 
Numbers next to project locations are 

FERC project numbers. 

Figure 3-1 

Location of Projects Included in Entrainment Database 

Page 3-2 Fish Entrainment at Hydropower Projects 
Georgia (1) 

South 

Carolina (6) 

New York (1) 

Figure 3-2 

Michigan (18) 

I 

Wisconsin (12) 

Distribution of Sites by State 

Included in the Entrainment Database 

Fish Entrainment at HvdroDower Proiects 

Minnesota (1) 

/ 

Pennsylvania (3) 

West 

Virginia (3) 

Pave 3-3 
3.0 • 4.9 MW (8) 

5.0 • 6.9 MW (5) 9.0 • 10.9 MW (3) 

7.0 • 8.9 MW (3) 

Figure 3-3 

Electrical Capacity of Sites 

Included in the Entrainment Database 

1000 • ZOOO cr. (11) < 1000 cr. ( 10) 

I 

:Z001·3000cC.(1) 5001 • 6000 er. (3) 

4001 • 5000 er. (4) 

3001 • <I 000 er. (7) 

Figure 3-4 

Hydraulic Capacity of Sites 

Included in the Entrainment Database 

Page 3-4 Fish Entrainment at Hydropower Projects 
determined by releasing fish in front of the 

turbines and recovering them in tailrace 

nets. Sometimes test fish were released 

directly into the mouth of the net. Other 

sites combined these two approaches (e.g., 

Thomapple)·. At some sites, both live and 

dead fish were released; other sites used 

either. Size and species of test fish, 

frequency of efficiency tests, and the 

statistical treatment of efficiency test results 

varied. 

Statistical derivation of entrainment 

estimates also varied substantially. Studies 

at some sites never reported an annual 

entrainment estimate, and insufficient 

information is available to derive it. At 

sites in South Carolina, the entrainment 

rates derived during the study year were 

applied to typical plant operating conditions, 

which in some cases were different from the 

conditions during sampling (both in terms of 

volume passing through the plant and 

amount of time that each unit operated). 

Elsewhere, the entrainment estimate 

represented only the year sampled. 

Entrainment rates derived from 

netting studies are based on either the 

number of fish per unit of time or unit of 

volume sampled. Rates are then applied to 

the amount of time that each unit operates 

during a year or the volume of water 

passing through each unit during a year to 

derive average annual entrainment estimates. 

At some sites with multiple units, the 

entrainment rate was assumed to be the 

same at sampled and unsampled units. 

Other studies attempted to account for 

differences in entrainment rates at different 

units. Entrainment estimates at some sites 

(e.g., Buchanan and Constantine) used 

geometric means of data to account for nonnormal distribution of the sampled 

population. Most studies, however, used 

arithmatic means. (FERC practice has been 

Fish Entrainment at Hydropower Projects 

to accept entrainment estimates derived from 

arithmatic means.) 

An important factor when considering 

comparability of data between sites is the 

minimum size of fish counted. For 

example, the minimum size hydroacoustic · 

target sampled at Hawks Nest was 3 inches. 

It would be difficult to compare these data 

to data from Centralia, where, according to 

netting results, most entrained fish were less 

than 1.5 inches. 

Often non-entrained fish are collected 

in tailrace netting, especially with partialflow nets. These fish add uncertainty to the 

estimated size distribution of fish collected 

during studies. Representativeness of 

independently derived species and size 

composition is a critical assumption in 

adjusting the fish counts derived from 

hydroacoustic studies. 

Comparing the size distribution of 

fish collected at the Centralia and Hawks 

Nest projects illustrates the potential 

significance of small fish in an annual 

entrainment estimate. Both sites used nets 

with 0. 75-inch bar mesh, yet the 

entrainment rates of small individuals were 

vastly different. This difference is probably 

due to different species assemblages (see 

Section 3.2.5 for more information on 

species assemblage influences). 

Although adjusting entrainment 

estimates in the database to include only fish 

over a certain size would make estimates 

more comparable, it would be difficult to 

select the appropriate size cut-off point. 

Many entrainment estimates derived from 

netting data include some fish less than 1.5 

inches; other estimates exclude fish less than 

3.0 inches (e.g., the hydroacoustic target 

limit at Hawks Nest). The minimum size of 

fish included in entrainment estimates may 

Page 3-5 
even vary at the same site, which is 

especially true with hydroacoustic methods 

because the minimum detection size varies 

under different sampling conditions. For 

example at Loud, the minimum size fish 

detected during optimum conditions was 2.0 

to 2.5 inches; under high flow conditions, 

the minimum size detected was 4 to 5 

inches. 

Another difficulty in adjusting 

entrainment estimates is that fish size 

information is not reported in a uniform 

manner. Some reports list the lengths of all 

fish collected (e.g., Buzzard's Roost for 

non-threadfm shad and Station 26). Others 

present size distributions by species or for 

all species combined (using a variety of size 

intervals) (e.g., Hawks Nest). Others report 

only the length range of entrained fish. 

Even if the entrainment estimates 

were adjusted to include only larger sized 

fish, this would effectively eliminate the 

majority of entrained fish. To make size 

comparisons, future size distribution 

reporting/recording requirements for fish 

collected in entrainment studies must be 

standardized (see Section 4.5). 

Variability of Results 

Given the range of study methods, 

plant characteristics, and fish populations 

represented, study results are quite diverse. 

Dam No.4 had the lowest estimated annual 

entrainment rate (0.6 fish/hour) and 

Buzzard's Roost had the highest (2,492 

fish/hour) (Table 3-1). 

On rivers with more than one 

entrainment study documented, the 

downstream-most project tended to have 

higher annual entrainment rates (e.g. , the 

Black, St. Joseph, Escanaba, Wisconsin, 

Broad, and Saluda rivers) than upstream 

Page 3-6 

projects. Hydropower projects are normally 

sized to accommodate available river flow, 

and downstream projects generally pass 

more water (and potentially more fish) than 

upstream projects. 

To account for variable plant 

hydraulic capacities, however, we calculated 

the flow-adjusted entrainment rate (annual 

entrainment rate divided by the plant 

hydraulic capacity in thousands of cfs) for 

each project. This adjustment eliminated the 

trend for the St. Joseph, Broad, and Saluda 

rivers. The trend remains strong at the 

remaining three rivers, however, which may 

be related to species-specific habitat 

preferences. For example, the annual 

entrainment rate on the Wisconsin River is 

driven by the abundance of young channel 

catfish (most of which were collected in July 

at all three sites). This species comprised 

only 5.1 percent of the entrainment estimate 

at the most upstream plant, Rothschild, 

whereas it comprised 32.7 and 75.3, 

percent, respectively, of the total 

entrainment estimates at the Wisconsin River 

Division and Centralia projects. Habitat for 

catfish would be expected to improve in the 

lower gradient reaches (generally 

downstream) of most rivers, which may 

partially explain the trend on the Wisconsin 

River. 

On the Menominee River, there is an 

inverse relationship in annual entrainment 

rates; more fish (mostly common shiner and 

bluegill) were entrained at the most 

upstream site than at the downstream site 

(mostly rock bass and bluegill). No 

upstream-downstream trends were evident 

on the Au Sable or Flambeau rivers. On 

rivers with obvious trends, however, the 

number of data points (two or three) is too 

low to predict any relationships based on 

river mile or location. 

Fish Entrainment at Hydropower Projects 
TABLE 3-1 (page l of 2) 

ANNUAL ENTRAINMENT RATES BY RIVER AND STATE 

River Annual Entrainment Rate 

State River Mile Site Fish/Hour I Fish/Hourlkcfs 

Michigan Au Sable 73 Mio 13.7 5.1 

38 Alcona 10.3 3.2 

33 Loud 18.6 7.1 

29 Five Channels 48.7 16.2 

22 Cooke 25.4 7.0 

12 Foote 17.7 4.4 

Mean 22.4 7.2 

Muskegon 89 Rogers 6.4 2.7 

58 Hardy 3.0 0.7 

47 Croton 25.1 6.8 

Mean 11.5 3.4 

Grand - Moores Park 9.8 8.2 

Black - Tower 3.4 9.4 

- Kleber 7.2 18.0 

Mean 5.3 13.7 

St. Josephs 103 Constantine 5.4 3.1 

33 Buchanan 8.0 2.1 

Mean 6.7 2.6 

Sturgeon 44 Prickett 13.2 20.6 

Escanaba 3 Escanaba Dam 3 2.5 2.0 

1 Escanaba Dam 1 5.2 4.4 

Mean 3.8 3.2 

Huron - French Landing 181.9 227.4 

Minnesota Mississippi 26 Lock & Dam #2 -- --

Wisconsin Menominee 55 White Rapids 16.5 3.2 

4 Park Mill 5.3 2.1 

Mean 10.9 2.7 

Brule 2 Brule 4.8 3.5 

Flambeau - Upper 6.4 8.9 

- Lower 11.8 12.7 

- Pixley 5.6 8.3 

- Crowley 7.6 5.1 

8 Thomapple 7.0 5.0 

Mean 7.7 8.0 

Fish Entrainment at .Hydropower Projects Page 3-7 
TABLE 3-1 (page 2 of 2) 

ANNUAL ENTRAINMENT RATES BY RIVER AND STATE 

River Annual Entrainment Rate 

State River Mile Site Fish/Hour I Fish/Hourlkcfs 

Wisconsin 

(cont.) Wisconsin 258 Rothschild 24.3 7.4 

220 Wis. River 80.6 15.7 

Division 

199 Centralia 95.2 26.2 

Meon 66.7 16.4 

Wolf - Shawano 4.6 5.5 

Georgia Savannah 220 King Mill 15.8 --

South Carolina Broad - Gaston Shoals 17.9 6.7 

- 99 Islands 18.6 4.1 

Mean 18.2 5.4 

Saluda - Saluda 8.3 10.4 

103 Hollidays Bridge 12.8 8.0 

60 Buzzards Roost 2492.2 623.0 

Mean 837.8 213.8 

Rocky 13 Abbeville 12.4 31.8 

West Virginia New 8 Hawks Nest 5.5 0.1 

Potomac 188 Dam#4 0.6 0.3 

Shenandoah 6 Millville 3.5 1.6 

Ohio/ Ohio 341 Greenup Lock & -- -- Kentucky Dam 

Pennsylvania Beaver 6 Beaver Falls 34.6 7.8 

Youghiogheny 73 Youghiogheny 212.4 132.7 

New York Genes see 7 Station 26 30.8 17.1 

Note: When more than one site is located on a river, the site at the most upstream location is listed first. 

Double dashes ( --) indicate that the rate could not be estimated. 

Page 3-8 Fish Entrainment at Hydropower Projects 
Many studies report variable or 

episodic entrainment over the course of the 

study year (e.g., Prickett, Brule, and Beaver 

Falls). Episodic entrainment events are 

usually more easily detected by 

hydroacoustic tec~ques because they 

generally sample a larger proportion of the 

total available time than possible using net 

tec~ques. The size and species 

composition of entrainment episodes, 

however, can best be characterized by 

netting. At the Youghiogheny entrainment 

study, the most comprehensive netting 

survey in the database, full-flow tailrace 

netting at both discharge bays was conducted 

continuously for a full year. Of the 

estimated annual entrainment of 1,578,452 

alewives, 45.3 percent were estimated to 

have been entrained during a 1-week period 

in early January. A relatively high 

entrainment rate of adult walleyes also was 

documented at the same time. One 

hypothesis to explain this extremely episodic 

entrainment is that the low water 

temperature caused alewives to become 

moribund and less able to escape the intake 

approach velocity. Walleye apparently 

followed the alewives into the vicinity of the 

turbine units, making them more vulnerable 

to entrainment. 

Diel Trends 

There were few consistent diel 

patterns (daily variances) of entrainment at 

the sites included in the database. Total 

entrainment rates were similar during the 

day and night at 10 of the 21 sites that 

addressed this issue. There were qualitative 

trends for certain species (such as ictalurids 

that generally were more commonly 

entrained during the night at Gaston Shoals), 

but some trends were only present during 

scattered months with no apparent pattern 

(e.g., Ninety-nine Islands and Saluda). 

Fish Entrainment at Hydropower Projects 

Entrainment rates were generally 

higher at night at most (eight of nine) of the 

sites exhibiting a diel trend for total species 

entrainment rate. At one of these sites, 

Buzzard's Roost, the entrainment rate of all 

species except the dominant species was 

more common at night, whereas threadfm 

shad were more common during the day. In 

contrast, at Youghiogheny, the alewife 

entrainment rate was six times greater at 

night. The intake at the Y oughiogheny 

Project is located at a depth of over 30 feet, 

but the Buzzard's Roost intake is relatively 

close to the surface (within 3 feet). 

The divergent trends in diel 

entrainment rates probably relates to 

behavioral characteristics of clupeids, which 

are plankton feeders. Because plankton is 

more prevalent in the upper water column 

during the day, they would be more 

susceptible to entrainment at a surfaceoriented intake during the day. Only one 

site, French Landing, reported consistently 

higher entrainment rates during the day, and 

entrainment at this site is dominated by 

black crappie and bluegill. 

Variation of Entrainment Between Years 

Most entrainment studies to date have 

been conducted over a 12-month period. 

The assumption with this approach is that 

the year sampled is representative of typical 

entrainment rates at that site. 

Entrainment studies at Millville and 

Dam No. 4, which were conducted over 

multiple years, provide data for assessing 

year to year variability of entrainment rates. 

Data from Millville are the most useful for 

this comparison because samples were 

collected during at least part of four 

different years, plant conditions were 

relatively stable, and the annual entrainment 

rate is more typical of the rates at other 

Page 3-9 
projects than Dam No. 4. Although there 

are some data available from two years for 

Dam No. 4, between the two years, a third 

unit was added. 

The database presents monthly 

entrainment rates for both Millville and Dam 

No. 4 for the single unit that was sampled. 

These rates are, therefore, valid for making 

between-year comparisons. Between-year 

comparisons for total annual entrainment 

rates at Dam No. 4, however, are not valid 

because the total entrainment rate for the 

second year includes extrapolated 

entrainment for the added unit. 

The relative abundance of species 

collected at Millville remained markedly 

similar from 1986 to 1991 in spite of the 

varying level of sampling effort (Table 3-2). 

Centrarchids and channel catfish were 

dominant species during all 4 years. On 

occasion, species that were usually 

infrequently collected were dominant in 

collections during a specific year (e.g., 

shorthead redhorse and American eel). In 

general, the four species most often 

entrained were relatively consistent. 

There also was relative consistency in 

abundance of species collected between 

years at Dam No. 4. Centrarchids and 

channel catfish comprised the top seven 

most frequently entrained species at this site 

in 1986. Other than some displacement by 

greenside darter and American eel, the 

species composition was similar during the 

2 years sampled. 

Even at these two sites with similar 

species composition from year to year, there 

is enough variability in peak entrainment 

timing to underscore the unpredictable 

nature of entrainment. At both sites any 1 

year of data would yield a reasonable 

approximation of the species most likely to 

Page 3-10 

be entrained, but periods of peak 

entrainment and entrainment rates varied 

between years. 

The total monthly entrainment rates at 

Millville during the four study years show 

some similarities for peak entrainment rate 

(Figure 3-5). In general, data indicate that 

the highest entrainment rates occur from 

April to June and drop precipitously in July 

or August. Considering that the dominant 

species are centrarchids, this drop 

corresponds with the period when most 

adults would be in near-shore areas guarding 

their nests and, therefore, would be less 

likely to be entrained. Peak entrainment 

rates again occurred in September and/or 

October in 1989 and 1991, presumably 

reflecting the entrainment of juvenile fish. 

A fall peak was not evident in 1986. 

If the annual entrainment rate for one 

year is assumed to be representative of other 

years, then shifts in monthly occurrence of 

peak entrainment rate are not important as 

long as the magnitude of the peak 

entrainment periods is comparable. 

Entrainment rates ranged from 3. 7 to 5.1 

fish/hour during April, 2.1 to 3.8 fish/hour 

in May, and 3.7 to 6.2 fish/hour in June, 

indicating reasonable agreement in the 

entrainment rate. Greater variability in 

entrainment abundance was evident in the 

fall, however, with rates ranging from 0.1 

fish/hour during 1986, when no fall peak 

was evident, to 3.5 fish/hour during 1991. 

Although the entrainment study plan 

for most projects called for only one year of 

data collection, in some cases there was 

overlap in the months sampled. This 

allowed monthly entrainment rates to be 

estimated for two separate years (Table 3-3) 

providing an additional measure of year to 

year variability. Comparative monthly rates 

(see Table 3-3) indicate that at some sites 

Fish Entrainment at Hydropower Projects 
TABLE 3-2 

RELATIVE ABUNDANCE OF ENTRAINED FISH COLLECTED AT 

:MILL Vll..LE FROM 1986 TO 1991 

1986 (5 months)* 1989 (4 months)* 1990 (9 months)* 1991 (12 months)* 

% Comp I Rank % Comp I Rank % Comp I Rank % Comp I Rank 

Bluegill 21.4 1 31.4 1 16.4 3 26.6 2 

Redbreast Sunfish 20.1 2 11.6 3 27.5 1 38.5 1 

Channel Catfish 17.1 3 25.0 2 13.1 4 2.8 6 

Smallmouth Bass 9.1 4 3.5 6 2.8 7 7.8 4 

Common Carp 7.9 5 2.3 8 1.1 8 0.3 13 

Yellow Bullhead 5.6 6 1.7 11 0.4 12 0.6 8 

Pumpkinseed 5.0 7 3.5 6 3.0 6 2.4 7 

Largemouth Bass 2.5 8 1.2 12 0.4 12 0.3 13 

Shorthead Redhorse 1.9 9 2.3 8 27.5 1 0.5 lO 

Rock Bass 1.8 lO 0.6 15 3.4 5 5.1 5 

Golden Redhorse 1.7 11 NC NC 0.1 23 NC NC 

Margined Madtom 1.3 12 1.2 12 <0.1 30 <0.1 23 

Green Sunfish 1.1 13 7.5 4 0.2 18 0.2 15 

White Crappie 1.0 14 NC NC NC NC NC NC 

UID Sunfish 0.2 20 4.0 5 0.3 14 0.1 17 

American Eel 0.4 17 2.3 8 0.1 23 11.8 3 

Black Crappie NC NC 1.2 12 0.2 18 0.1 17 

Number of Fish 1995 199 3520 5321 

Collected 

* Number of Months Sampled 

NC = Not Collected 

Fish Entrainment at Hydropower Projects Page 3-11 
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Page 3-12 

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Millville Monthly Fish Entrainment for 

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Fish Entrainment at Hydropower Projects 
TABLE 3-3 

YEAR-TO-YEAR VARIABILITY IN TOTAL MONTHLY ENTRAINMENT 

RATES AT SITES INCLUDED IN THE DATABASE 

(Fish per Hour) 

Site I Year I April I May I June I July I August I Septrnbr. I Octbr. 

Moores 1 -- -- -- -- -- 13.80 -- Park (69 F) 

2 -- -- -- -- -- 19.50 -- (75-76 F) 

Tower 1 11.35 -- -- -- -- -- -- (67 F) 

2 9.16 -- - -- -- -- -- (54-56 F) 

Kleber 1 111.38 -- -- -- -- -- -- (65 F) 

2 0.70 -- -- -- -- -- --

(40-45 F) 

French 1 -- -- -- 774.40 -- -- -- Landing 

2 -- -- -- 121.40 -- -- --

Station 1 -- -- 8.80 24.60 115.40 55.90 128.70 

26 

2 -- -- 6.80 23.20 38.50 37.30 61.50 

Darn 1 1.88 1.61 0.94 0.30 0.13 0.65 0.16 

No.4 

2 0.50 0.50 0.30 0.80 0.30 0.60 0.40 

Note: All entrainment rates except those for Station 26 derived from netting data. Water temperature at 

the time samples were collected (when available) shown in parenthesis. Refer to Figure 3-5 for 

comparison of monthly rates at Millville. 

Fish Entrainment at Hydropower Projects Page 3-13 
monthly entrainment rates were similar; at 

others, entrainment rates were two to more 

than 100 times greater during the same 

month but different years. In some cases, 

this variation may be caused !:>y temporal 

shifts in peak entrainment events related to 

environmental factors such as water 

temperature which influences fish 

movements (e.g., an unusually cold spring 

may postpone increased centrarchid activity 

from April to May). Substantially cooler 

water temperatures may have caused the 

dramatically different entrainment rates 

during April at Kleber (Table 3-3). At 

Tower and Moores Park slightly higher 

entrainment rates were associated with 

higher water temperatures. Monthly water 

temperatures at Millville were generally 

comparable for the 3 years for which data 

were available. Year to year variability may 

reflect the episodic nature of many 

entrainment events and whether these 

episodes coincided with the entrainment 

sampling effort. 

In some cases entrainment rates are 

higher when water temperatures are higher. 

Sampling during a warmer-than-average year 

may provide a conservative entrainment 

estimate. One obvious exception to this is 

when extremely low temperatures result in 

high entrainment rates of moribund fish. 

When entrainment sampling results indicate 

episodic entrainment due to unusual 

temperature conditions, available long-term 

temperature records can be consulted. Such 

records could show the expected recurrence 

rates of such temperatures and any resultant 

episodic entrainment. 

Entrainment of Rare Species 

According to entrainment reports, 

collection of rare species of fish is 

infrequent. State-listed threatened species 

were only collected at two sites in the 

database: Buchanan and Rothschild. A 

Page 3-14 

single river redhorse, listed by Michigan as 

threatened, was collected at Buchanan. A 

black buffalo and greater redhorse, both 

listed as threatened by Wisconsin, were 

collected at Rothschild. Because both 

individuals collected at Rothschild were too 

wide to fit through the 1.4-inch trashracks, 

however, they probably are the result of 

tailrace intrusion. We found no accounts of 

entrained federally-listed threatened or 

endangered species in the database reports. 

3.2.2 Comparison of Different Sampling 

Techniques 

Studies included in the database used 

three basic methods for sampling: 1) 

partial-flow netting, 2) full-flow netting, and 

3) hydroacoustics. Partial-flow netting was 

most frequently used in the tailrace. Where 

this was impractical, partial-flow net 

sampling was conducted in front of the 

turbines. Full-flow netting most often was 

used in the tailrace of one or more units, 

and hydroacoustics normally sampled fish in 

front of the turbines. 

Partial-Flow Netting 

Partial-flow netting provides data on 

species and size composition when full-flow 

tailrace netting is not possible because of 

physical limitations, high through-turbine 

discharges (e.g., Lock and Dam No. 2 and 

Greenup Lock and Dam), or when 

hydroacoustic techniques are the primary 

method for estimating entrainment. 

Partial-flow tailrace netting often 

samples resident fish in the tailrace that are 

not entrained, however, which causes 

overestimates of entrainment. Intrusion can 

introduce substantial error into the estimated 

size distribution, because large fish are 

common in tailraces. If the net is positioned 

in relatively low velocity water, fish may 

also swim out of the net after being 

Fish Entrainment at Hydropower Projects 
collected. Sampling a zone in front of the 

turbines where all fish are not committed to 

entrainment can result in under- or 

overestimation of entrainment rates. Any 

net sampling behind the trashracks, 

however, can cause serious damage to the 

turbines if a net breaks loose. 

Full-Flow Netting 

Full-flow tailrace netting is normally 

preferable to partial-flow netting because of 

the larger flow volume sampled and because 

tailrace intrusion of fish is limited. Some 

tailrace intrusion still may occur with use of 

full-flow tailrace netting, most likely 

through gaps between the net and the 

powerhouse. 

Netting Techniques Compared 

Entrainment rates as measured by 

partial and full-flow tailrace netting were 

estimated at the Rogers Project. Partialflow tailrace sampling was used at the 

discharge of units 3 and 4 (estimated aerial 

coverage: 8.5 percent) year-round. Partialflow netting also was used at the discharge 

of Units 1 and 2 from January, March, and 

early April; after mid-April full-flow tailrace 

netting was used. The database segregates 

data for Rogers by unit and presents the. 

combined entrainment estimate for the entire 

plant to make it easy to compare the two 

collection techniques. 

The licensee's consultant conducted 

an analysis of variance (ANOV A) to 

compare the collection densities and lengthfrequency distributions of fish collected on 

four separate sampling dates in September 

and October (when entrainment rates were 

relatively high and not considered to be 

biased). Results indicated no significant 

difference between the two sampling 

methods. The licensee did not, however, 

conduct an ANOV A to assess sampling 

Fish Entrainment at Hydropower Projects 

method differences during the spring. 

Tailrace intrusion was suspected at other 

sites sampled by partial-flow tailrace netting 

during the spring due to localized spawning 

migrations of walleye and white sucker. 

Annual entrainment estimates for 

Units 1 and 2 (25,059) and Units 3 and 4 

(30,816) were similar. Monthly entrainment 

rates for all species and sizes combined 

showed somewhat greater variability, 

ranging from 0. 00 to 6. 95 fish/hour at Units 

1 and 2 and 0.2 to 11.7 fish/hour for Units 

3 and 4 during April to December. 

Entrainment rates for June, August, 

September, and December were comparable 

but dissimilar (differences of 2 to 40 fold 

with the partial-flow estimates always 

higher) for April, May, July, and October. 

Species-specific monthly entrainment 

rates also were usually similar. More 

shorthead redhorse and chinook salmon were 

collected in full-flow nets (Units 1 and 2), 

however, than in partial-flow nets (Units 3 

and 4). Most shorthead redhorse and 

chinook salmon were relatively large (9 to 

17 inches) and may be able to sense the 

presence of the partial-flow net and have 

sufficient burst swimming speed to avoid 

capture. Further investigations would be 

necessary to confirm this hypothesis, but the 

Rogers data suggests the potential to 

underestimate entrainment rates of certain 

species with partial-flow netting. There was 

no apparent source of bias from unit 

location. 

The Rogers data indicate that partialflow tailrace net results are similar to those 

of full-flow nets. The average monthly 

entrainment rate (all species) estimated by 

partial-flow nets was either comparable or 

higher than for full-flow nets. According to 

these data, partial-flow nets give a 

conservative estimate of the entrainment 

Page 3-15 
rate. For some species (e.g., shorthead 

redhorse and chinook salmon), however, 

entrainment estimates may not be 

conservative. Partial-flow nets should be 

positioned in high velocity locales to 

minimize possible tailrace intrusion and fish 

swimming out of the net after capture. 

Hydroacoustics 

Hydroacoustic techniques have the 

advantage of providing potentially less costly 

continuous sampling at many different 

locations. Fish also can be counted without 

incurring injury or death, which sometimes 

results from other collection techniques. A 

disadvantage of hydroacoustic techniques is 

that with high noise, it may be difficult or 

impossible to obtain accurate hydroacoustic 

counts of all but the largest fish. In 

addition, low intake velocities often preclude 

the use of this technique because fish 

detected may not be committed to 

entrainment. Some net collections to 

confirm the species and size distribution 

must be used unless these parameters are 

clearly evident (e.g., juvenile blueback 

herring at Mohawk River sites). 

Entrainment rate estimates obtained 

b~ ~ydroacoustics and netting are usually 

within three-fold of each other and, in some 

cases, quite similar. Table 3-4 compares 

total entrainment estimates obtained using 

both methods at the same site. Estimates 

obtained by partial-flow tailrace netting were 

lower than the hydroacoustic estimate in six 

of seven cases. Because netting at these 

seven sites was primarily intended to 

provide species and size distribution 

information in conjunction with 

hydroacoustic estimates, however, the net 

collection effort was relatively low (24 to 48 

hours per month) and the mean number of 

fish collected per year at these seven sites 

was only 301 (range: 60 to 851). The 

entrainment rate estimates are not as precise 

Page 3-16 

as estimates based on larger numbers of 

collected fish. Estimates obtained by fullflow netting (nine comparisons) or partialflow turbine gallery netting (one 

comparison) were similar in three cases and 

higher (more conservative) than the 

corresponding hydroacoustic estimates in 

seven of ten cases. Generally, over 1,000 

fish were used to derive full-flow and 

partial-flow turbine gallery netting annual 

entrainment rate estimates. These data 

indicate that sampling with full-flow tailrace 

nets and possibly partial-flow turbine gallery 

nets gives conservative estimates of 

entrainment rates. 

Table 3-4 shows the variability in the 

minimum detectable size ( 1 to 5 inches) of 

hydroacoustic targets between sites and, in 

some instances, at the same site. The table 

also illustrates the variability in mesh sizes 

used in netting studies (0.25- to l-inch bar). 

Estimating the size effectively sampled by 

net is difficult because it is influenced both 

by mesh size and flow characteristics. The 

importance of establishing standardized 

acceptable mmtmum sized fish for 

entrainment rate estimates is apparent if you 

consider that more than 50 percent of the 

annual entrainment estimate at Centralia 

comprises fish that are less than 1.5 inches 

long. 

3.2.3 Relative Entrainment Between 

Units and Influence of Intake 

Configuration on Entrainment 

Rates 

Entrainment rates may differ between 

units because of temporal and spatial 

factors. The most common temporal factor 

is the amount of time that a unit is operated. 

Units that operate more frequently than 

others tend to entrain more fish. For 

example, 62 percent of the entrained fish at 

Fish Entrainment at Hydropower Projects 
TABLE3-4 

COMPARISON OF TOTAL ANNUAL ENTRAINMENT RATES 

DERIVED BY HYDROACOUSTIC AND NETTING TECHNIQUES 

H ydroacoustics Netting 

Minimum Size Detected 

(inches) Under Annual Annual Type Net Bar 

Following Conditions Rate<2> Rate<2> of Size 

High (fish/hr) (fish/hr) Net<3> (inches) 

Site Optimum<l) Discharge 

Alcona 2-3 -- 10.27 5.26 PFfR 1 

Cooke 1.75 -- ~ 6.30 PFfR 1 

Loud 2-2.5 4-5 18.55 1.87 PFfR 1 

Mio 1.75 3-4 13.74 4.34 PFfR 1 

Five Channels 2-3 -- 48.73 2.50 PFfR 1 

Croton 1.75 3 25.09 17.00 PFfR 1 

Hardy 1.75 3 2.96 12.40 PFfR 1 

Park Mill -54dB(4) -- 5.31 5.56 PFI'G 0.75 

Moores Park 2 -- 9.80 10.65 FFfR 0.25 

Tower 2 -- 3.40 3.08 FFfR 0.25 

Kleber 2 -- 7.20 17.34 FFfR 0.25 

White Rapids 1 -- 5.92 16.50 FFfR 0.75 

Brule 1 -- 2.89 4.80 FFfR 0.75 

Crowley 2 -- 7.90 7.60 FFfR 0.25 

Shawano -- -- 4.60 4.90 FFfR 0.25 

99 Islands 4 -- 18.60(S) 27.20 FFfR 0.75 

Gaston Shoals 4 -- 10.50 17.90 FFfR 0.75 

(1) Optimum = low discharge, minimal extraneous sound. 

{2) Underlined annual rate is considered to be the best estimate by the applicant and/or resource 

agency. In cases where the hydroacoustic estimate was considered most representative, the 

primary purpose of the netting samples was to provide species composition and length frequency 

information to apply to the hydroacoustic data. 

{3) PFfR = Partial flow tailrace netting; PFfG = Partial flow turbine galley netting; FFfR = Full 

flow tailrace netting. 

(4) Acoustic size presented in decibels; actual size not presented. 

{5) Annual entrainment estimate adjusted for proportion of fish collected in nets that were less than 

four inches long. 

Fish Entrainment at Hydropower Projects Page 3-17 
White Rapids were detected at Unit 1, which 

operated twice as much as the other two 

units. Similarly, 68 percent of entrained 

fish at Brule were detected at Unit 2, which 

operated more frequently than the other 

units. At Y oughiogheny, 73.3 percent of all 

fish were collected at Unit 1. This unit was 

operating during a 1-week entrainment 

episode in early January when nearly half of 

the annual alewife entrainment occurred. 

Another temporal factor influencing 

entrainment rates between units is volume 

per unit of time. The south unit at Moores 

Park entrained twice as many fish as the 

north unit because wicket gate problems 

reduced the flow through the north unit. At 

Rothschild, only 21 percent of the fish were 

collected at one of the two units sampled. 

The unit with higher entrainment had greater 

flow and higher approach velocities. 

Spatial factors also influence 

differences in entrainment rates between 

units and, in some cases, within the forebay 

of the same unit. Some plants have a 

forebay configuration in which one unit is 

much closer to the shoreline than other 

units. Unit-specific entrainment studies at 

such sites show that entrainment abundance 

is generally higher at near-shore intakes. 

Hydroacoustic studies at Shawano illustrate 

this trend. Of the targets, 55 percent were 

detected at the shoreside intake, 33 percent 

at the center intake, and 12 percent at the 

riverside intake. The same trend was 

documented at Greenup Lock and Dam, 

where more fish were collected at the nearshore intake during all three seasons that 

were sampled. This pattern was attributed 

to the tendency for fish to follow the 

shoreline of rivers. At both Shawano and 

Greenup Lock and Dam there are no power 

canals or other structures that would tend to 

evenly distribute fish across the intakes. 

Differences between units also were evident 

Page 3-18 

at Park Mill, where more than twice as 

many fish were collected in the net closest 

to an area of relatively still water within the 

forebay area. 

Several additional entrainment studies 

illustrate the effects of intake location on 

entrainment. The intake of Escanaba Dam 

1 is in a relatively shallow portion of the 

impoundment. Most of the entrained fish 

were sunfish, which most frequently are 

found in shallow-water habitats. The peak 

entrainment rate noted in June was attributed 

to increased sunfish activity as they moved 

to their preferred spawning and residence 

areas, and the October peak was attributed 

to entrainment of young-of-the-year 

centrarchids. Considerably fewer sunfish 

were entrained at Escanaba Dam 3, where 

the Dam 3 powerhouse is located near the 

center of the dam, away from the shallow, 

littoral zone favored by sunfish. 

The proximity of shallow, near-shore 

habitat also appeared to influence 

entrainment at the Kings Mill Project on the 

Augusta Canal. A bed of aquatic plants is 

located immediately upstream of the 

shoreline intake of this project. The 

October peak in the entrainment rate 

correlated with the senescence of aquatic 

plants; those fish that normally rely on these 

plants for cover would be more wideranging when the cover is gone and thus 

more vulnerable to entrainment. One 

proposed protective measure at this site was 

to reconfigure the intake by constructing a 

wall on the upstream side to withdraw 

water from the deeper part of the canal 

rather than in proximity to shallow water 

nursery areas. 

The influence of the proximity of the 

intake to the shoreline also is evident at the 

Beaver Falls Project. The entrainment catch 

at this site was strongly dominated by 

Fish Entrainment at Hydropower Projects 
gizzard shad (85. 6 percent of the entrained 

population), the same species that dominated 

the catch at Greenup Lock and Dam where 

there was a positive relationship between 

proximity of the unit to the shoreline and the 

entrainment catch. 

The intake to the Beaver Falls Project 

is flush with the shoreline and separated 

from the dam spillway by a pier. Full-flow 

tailrace netting was used to sample one of 

the two intakes at this project. Only one 

unit was operated during much of the 

entrainment study, but a study was 

conducted to determine the validity of 

applying the entrainment rate at the sampled 

unit (determined volumetrically) to the 

unsampled unit. Two day-time trials and 

one night-time trial were conducted. 

Sampling was performed for equal periods 

of time with one and two unit operation. 

Study results showed an 87 to 88 

percent decrease in entrained fish density at 

the sampled unit during two-unit operation. 

Forebay turbulence and noise during twounit operation may have deterred schooling 

young gizzard shad from entering the intake. 

The study concluded that sampling 

entrainment at only one unit probably 

overestimated the total plant entrainment 

rate. The annual entrainment estimate from 

the sampled unit was presented as a 

conservative estimate of the total plant 

entrainment (i.e., the volume of water 

passing through the unsampled turbine was 

not considered in deriving the annual 

entrainment estimate for the facility). It is 

debatable whether or not this conclusion was 

justified by the available data. It is evident, 

however, that the entrainment rate at the 

Beaver Falls Project with two units 

operating is not double the entrainment rate 

of a single unit operating. 

Fish Entrainment at Hydropower Projects 

We compared entrainment rates at 

sites with forebay intakes to those with 

power canal intakes. Eight sites in the 

database have a power canal intake. Annual 

entrainment rates at seven of these projects 

(Constantine, Buchanan, Prickett, Park Mill, 

Upper, Hollidays Bridge, and Millville) 

range from 3.50 to 13.24 fish/hour (Table 

3-1) and are comparable to those with 

forebay intake configurations. The eighth 

site is Centralia, where the annual 

entrainment rate of 95.20 fish/hour is higher 

than the rate at most plants with forebay 

intakes, but comparable to the 80.60 

fish/hour at the plant upstream of Centralia 

which has a forebay intake, Wisconsin River 

Division. Study results show that the 

entrainment rate at projects with power 

canals is likely to be of similar magnitude to 

those projects with forebays. 

The intakes to three sites in the 

database are oriented parallel to the 

prevailing flow. One site, the King Mill 

Project, illustrates that proximity to 

shoreline habitat may influence entrainment 

rate. The other two sites, Buchanan and 

Station 26, illustrate other influences on 

entrainment rates. 

The intake at Buchanan is on a 

power canal that diverts water from the St. 

Joseph River. All 10 units are located on 

one side of the canal, which dead-ends 

adjacent to Unit 10. Entrainment sampling 

was conducted at Units 4, 7, and 9. The 

dominant species collected were chinook 

salmon and rainbow trout smolts. Both 

species were stocked 30 miles upstream of 

the project in March, April, and May, and 

were collected at Buchanan during April, 

May, and June. Most chinook salmon and 

rainbow trout, as well as resident species, 

were consistently collected at Unit 9, which 

is the unit closest to the dead-end of the 

canal. No chinook salmon or rainbow trout 

Page 3-19 
were collected at Unit 4. The total number 

of fish collected at each unit was: 

• Unit 4- 181; 

• Unit 7- 700; and 

• Unit 9- 2218. 

There is distinct pattern of increased 

entrainment rate with increased proximity to 

the end of the power canal. 

The Rock Island Dam powerhouse on 

the Columbia River (Raemhild et al. , 1984), 

which has an intake configuration similar to 

that at Buchanan, showed a similar pattern. 

Ten turbine units were monitored during the 

period of peak downstream migration of 

salmon and steelhead (rainbow trout). The 

unit closest to the end of the power canal 

entrained 35 percent of the total catch; the 

seven units closest to the upstream end of 

the canal each entrained no more than 5 

percent of the total catch. 

The intake to Station 26 (in New 

York) is parallel to the main flow of the 

Genesee River. It is immediately upstream 

of a dam and directly across from a nonpower related intake structure that also is 

oriented parallel to the river flow. Both 

power and non-power intakes run along the 

shoreline. Entrainment at this site is 

dominated by clupeids (an estimated 83.4 

percent of entrained fish), most of which are 

gizzard shad. There was a shift in passage 

from the upstream end of the intake 

structure in June to the downstream end in 

September that was documented by 

hydroacoustic techniques. Based on netting 

collections, the spring entrained fish were 

spottail shiner and the fall entrained fish 

were gizzard shad. The indicated shift over 

time from upstream to downstream 

entrainment, therefore, is probably due to 

changing species composition rather than to 

changing behavioral patterns of the same 

Page 3-20 

species. Overall, the middle intake bays 

exhibited the lowest entrainment rate. 

Another important aspect of the 

Station 26 entrainment study is the avenue 

of downstream fish movement. Passage 

through the powerhouse, through a nonpower intake across the river from the 

powerhouse intake, and over the dam 

spillway was monitored hydroacoustically. 

Analysis indicated that most fish passed over 

the spillway. During the 9 months of 

concurrent monitoring of the power and 

non-power intakes, however, the 

entrainment rates (fish/hour) through each 

intake were comparable. This is especially 

noteworthy because the flow through the 

non-power intake averaged 75 cfs, and the 

flow through the power intake averaged 

1 ,594 cfs. This is consistent with the trend 

at the Beaver Falls Project that entrainment 

rates at sites dominated by clupeids are not 

necessarily related to water volume through 

the intake. 

3.2.4 Horizontal and Vertical 

Distribution Within Units 

Sometimes the location of 

hydroacoustic transducers allows assessment 

of distribution trends within individual 

forebays. At Croton, Tower, and Unit 1 of 

Mio there was no horizontal distribution 

pattern of entrainment. At Alcona, 

however, 81 percent of the hydroacoustic 

targets were detected along the right or left 

side of the intake and only 19 percent in the 

center of the forebay. The same pattern 

occurred at Unit 2 of Mio with only 19 

percent passing through the center of the 

forebay. The horizontal distribution 

assessment at Foote showed that two-thirds 

of the fish were detected along the forebay 

side closest to the shoreline of the two units 

sampled. 

Fish Entrainment at Hydropower Projects 
Reported vertical distribution patterns, 

determined hydroacoustically, were 

inconsistent. There was no pattern at 

Croton, Kleber, or Station 26, and fish 

tended to be slightly deeper during the day 

at Park Mill. Entrained fish were more 

frequently detected in the top of the water 

column at Tower, Lock and Dam No. 2, 

Crowley, and Ninety-nine Islands, and fish 

were most often detected at mid-depth at 

Moores Park. At Saluda and Hollidays 

Bridge, there was no vertical trend for most 

of the period sampled, but during November 

to January, more fish were detected at the 

top of the intake at Saluda, and during 

November and December, more fish were 

detected at mid-depth at Hollidays Bridge. 

3.2.5 Quantitative Trend Analysis 

We conducted quantitative analyses of 

entrainment data in two parts. First, we 

performed an exploratory regression analysis 

to identify statistically significant trends 

between entrainment rates and single 

physical variables that were subjectively 

determined to have potential significance. 

This exploratory analysis also examined the 

effects of individual, high-leverage 

observations in the data set that explained 

most of the statistically significant . 

associations between the entrainment rate 

variables and other physical parameters. 

The second part of the analysis included a 

correlation analysis, a principal components 

analysis, and a regression analysis on a 

larger set of variables. Our second analysis 

did not evaluate the effect of high-leverage 

observations on the significance of the 

associations. In our second set of regression 

analyses we used a species assemblage 

covariate that was not used in the 

exploratory regression analysis. 

Fish Entrainment at Hydropower Projects 

Exploratory Regression Analysis 

We conducted the exploratory analysis 

to identify statistically significant trends or 

associations between entrainment rates and 

individual physical characteristics of the 

hydro projects, waterbodies, or their 

reservoirs. We used the "Fit Y by X" 

platform in JMP to fit linear and quadratic 

lines for each variable. 

The database includes a fairly large 

range of values for the independent physical 

site parameters evaluated. The distribution 

of observations within each range tends to 

be clustered except for a few observations. 

These non-clustered observations can exert 

disproportionate leverage on the significance 

and degree of association between variables. 

We used a series of regression analyses with 

a single variable to identify associations 

between the variables. We did not classify 

as significant those associations established 

by the value of a high-leverage observation. 

We used a 0.05 probability level as the 

significance criterion. We also visually 

reviewed the scatter plots for weak trends 

that could not be identified by calculation of 

a 0. 05 probability level. 

Site parameter variables include: 

reservoir surface size, reservoir length, total 

reservoir storage, plant flow, reservoir flush 

rate, depth of intake, trashrack spacing, and 

average velocity. We tested each variable 

against the average annual entrainment rate 

(fish/hour) and the flow-adjusted 

entrainment rate ([total fish/hour]/kcfs). 

Where entrainment rates had not been 

extrapolated to all units, we substituted the 

capacity of the units represented by the 

entrainment rate estimate (the entrainment 

flow) for the plant capacity for this 

calculation (see column H5 of the database 

in Appendix 3). 

Page 3-21 
When SWEC constructed the 

database, it seemed that if there were 

clupeid species at a site, there were higher 

entrainment rates. Each analyses described 

above, however, also was conducted using 

a modified database excluding sites where 

the entrainment rate was dominated by 

clupeids (King Mill, Buzzard's Roost, 

Hawks Nest, Greenup Lock & Dam, Beaver 

Falls, Youghiogheny, and Station 26). 

Because some resource agencies question the 

acceptability of entrainment rate estimates 

derived by hydroacoustic and partial netting 

techniques, we also performed additional 

analyses using only full-flow tailrace netting 

at sites not dominated by clupeids. 

To account for watershed variations, 

we conducted separate analyses for three 

basins with more than four sampled sites: 

the Au Sable River Basin (Alcona, Foote, 

Cooke, Loud, Mio, and Five Channels), 

located in Michigan; the Flambeau River 

Basin (Thornapple, Crowley, Upper, Lower, 

and Pixley), located in Wisconsin; and 

Broad River Basin (99 Islands, Gaston 

Shoals, Saluda, Hollidays Bridge, and 

Buzzard's Roost), located in South Carolina. 

We did not include two sites (Lock 

and Dam #2 and Greenup Lock and Dam) in 

the 45-site database in our statistical 

analyses or summaries because they did not 

offer reliable entrainment rate estimates. In 

the 43 studies that were available for 

analysis, the values for one or more 

variables (other than entrainment rate) 

sometimes were incomplete. The number of 

observations available for analysis is set by 

the number of non-missing values for the 

specific variable. We could not always 

conduct watershed analyses because of 

missing values. For some variables, such as 

usable reservoir storage, a meaningful 

analysis could not be conducted because of 

limited available data. 

Page 3-22 

We summarize results of our 

exploratory data analyses in the following 

section. Details of this statistical analysis 

are presented in Appendix 4. 

Reservoir Size 

Neither the linear nor the quadratic 

analyses yielded a significant positive 

association between reservoir size (as 

measured by surface acres) and flowadjusted or average entrainment rate when 

two high-leverage sites were dropped from 

the analysis. The watershed-based analysis 

also showed no significant relationships 

between entrainment and impoundment size 

when high-leverage sites were dropped from 

the analysis. The trends in the occurrence 

of high-leverage sites are typically repeated 

for each variable analyzed. Sites such as 

Buzzard's Roost, which have high 

entrainment rates and larger reservoir size, 

flush rate, plant flow, total reservoir 

storage, and depth, show high-leverage 

observations for each variable. 

The 24 exploratory analyses relating 

entrainment rates to reservoir size showed 

no consistent, significant trends in the 

database for this variable. 

Reservoir Length 

The 24 exploratory analyses relating 

entrainment rates to reservoir length showed 

no significant associations. 

Total Reservoir Storage 

The 24 exploratory analyses relating 

entrainment rates to total storage showed no 

significant associations when one or two 

large reservoir sites with high entrainment 

such as Youghiogheny and Buzzard's Roost 

were dropped from the analysis. 

Fish Entrainment at Hydropower Projects 
Plant Flow 

The analysis for all data showed no 

significant trends in either flow-adjusted or 

average entrainment rates and plant flow 

with or without the Hawk's Nest, Buzzard's 

Roost, and Prickett sites (all high-leverage 

for this variable). When the high-leverage 

Buzzard's Roost site was dropped from the 

watershed analysis, the two analyses for the 

remaining four Broad River sites showed an 

interesting trend in plant flow: for the flowadjusted entrainment rate, there was a 

significant negative association with plant 

flow, while the average entrainment rate was 

not significant but the scatterplot showed a 

positive association with plant flow. An 

association was observed for the Broad 

River sites after one high-leverage data point 

was removed; however, this association was 

based on only four remaining observations. 

There are two possible inferences for 

the Broad River sites: 1) more fish/hour are 

entrained at the higher flow sites, and 2) the 

numbers of fish/hour adjusted for flow rate 

decrease in proportion to flow. The first is 

intuitive, perhaps expected at any hydro 

project, and it is surprising that the other 

watershed analyses for this variable are not 

similar, although pulses of large numbers of 

young-of-the-year fish may mask this trend. 

The second inference is less intuitive and 

may be an artifact of other physical 

conditions associated with plant flow. There 

are no obvious reasons for these trends. 

Some "significant" trends may occur by 

chance alone. 

Through-plant Reservoir Flush Rate 

Many of these analyses produced 

significant positive associations with flush 

rate. In most cases, however, significance 

disappeared when a single observation was 

eliminated. 

Fish Entrainment at Hydropower Projects 

Depth of Intake Submergence 

None of the initial analyses on this 

variable yielded significant associations. 

Even when the Buzzard's Roost and 

Youghiogheny sites (which have greater 

entrainment rates than the other sites) are 

dropped from the analysis, there were no 

significant trends. 

Trasbrack Spacing 

The analyses show no consistent 

associations between entrainment rate and 

the single variable of trashrack spacing, 

perhaps because the majority of entrained 

fish are small and easily pass through typical 

trashrack spacings at sites where entrainment 

studies have been conducted. 

Average Intake Velocity 

There were no significant trends 

between entrainment rate and average 

velocity. 

Conclusions of Exploratory Analyses 

Our analyses of variables for which 

meaningful amounts of information are 

available indicate no consistent statistically 

significant trends for total number of 

entrained fish. Analyses for individual 

species could be undertaken, but the speciesspecific data sets contain even fewer 

observations than those used for total 

species. The species-specific data appear to 

be at least as variable, if not more so than 

the data for total entrainment rates. Much 

of the variability probably relates to 

sampling and reporting methods that vary 

among studies. 

Page 3-23 
Supplemental Analyses 

Correlation Analysis 

Correlation; which is a measure of 

association between variables, can vary from 

-1 to + 1 in value. A correlation value of 1 

between two variables indicates a close and 

positive association between the values of 

the .two variables. A correlation of 0 

indicates no association and an independence 

in the values of the two variables. A 

correlation value of -1 between two 

variables indicates a close and negative 

association between the values of the two 

variables. 

We compared the correlation of 11 

physical site parameters with both the 

average entrainment rate and the flowadjusted entrainment rate (average 

entrainment per 1,000 cfs plant capacity). 

We used the JMP (SAS, 1989) analysis 

platform "Y's by Y's" to calculate the 

Pearson product moment correlation and 

scatterplot matrices. We created a separate 

table of correlations for each entrainment 

rate. Each table shows correlation 

coefficients- for each combination of the 11 

variables. To accompany each table, we 

also created a scatter plot matrix for each 

pair of observations. We provide details of 

this analysis in Appendix 5. 

Our analysis showed high positive 

correlation of the flow-adjusted entrainment 

rate with usable storage (0.9964), reservoir 

width (0.9962), and reservoir flush rate 

(0.9584). The cross correlation (correlation 

among the independent, non-entrainment 

rate variables) of these three variables also 

was very high. These high correlations 

were expected, as the previous regression 

analyses showed that one or two highleverage observations lead to significant 

associations. Those same high-leverage 

Page 3-24 

observations are contained in the data set 

used for the correlation, principal 

components, and additional regression 

analyses. 

The average entrainment rate showed 

a high, positive correlation with average 

velocity (0.9959) and trashrack spacing 

(0.9559). The average entrainment rate was 

also negatively correlated with reservoir 

length (-0.9480). Trashrack spacing was 

cross correlated with average velocity. 

Reservoir length showed a high negative 

cross correlation with average velocity and 

trashrack spacing. Other non-target 

variables with high positive cross correlation 

included: reservoir size and total storage; 

reservoir size and reservoir (through-plant) 

flush rate; and, entrainment flow and plant 

flow. 

Some correlations are expected based 

on typical engineering practices used at the 

time the plants were designed and on the 

physical conditions of the site. For 

example, reservoirs with large usable 

storage are generally also relatively wide. 

Also, a project designed with a relatively 

high average water velocity probably has 

large trashrack spacing. 

Correlation of the flow-adjusted 

entrainment rate with usable storage and 

reservoir width indicates that the rate of 

entrainment per unit flow increases with the 

usable storage and reservoir width. The 

correlation of the flow-adjusted entrainment 

rate and reservoir flush rate may be because 

both variables are functions of flow rate. 

Average entrainment rate is cross 

correlated with average velocity and 

trashrack spacing. Sites with high average 

velocity generally have larger trashrack 

spacing. The average entrainment rate is 

negatively correlated with reservoir length, 

Fish Entrainment at Hydropower Projects 
which indicates that shorter reservoirs in the 

data set were associated with higher 

entrainment rates. 

The high correlations observed for 

entrainment rates with various physical 

variables and the cross correlation among 

the physical variables do not, however, 

indicate a ·predictive trend in entrainment 

variables. Correlation only explains 

associations between variables in a data set. 

Although this analysis did not review the 

effects of the high-leverage observations 

identified during the exploratory analysis, 

these high-leverage observations probably 

have many observed correlations. 

Principal Components Analysis 

Principal components analysis 

develops linear combinations of variables 

that explain the greatest amount of variation. 

The coefficients of these linear 

combinations, which are called eigenvectors, 

are calculated from the correlation matrix. 

There are as many linear combinations (or 

principal components) calculated as there are 

variables of interest. Each linear 

combination accounts for a particular 

amount of data variability. When the data 

are highly correlated and a large number of 

variables of interest are included in the 

calculation, a few principal components 

account for nearly all the variability in the 

data set. The individual values of the 

eigenvectors cannot be used to judge the 

correlation of individual pairs of variables. 

We conducted the principal 

components analysis with 11 physical site 

parameters and one of the two entrainment 

rate variables; the analysis was conducted 

twice. We used the JMP (SAS, 1989) 

analysis platform "Spin" with the principal 

components option to calculate the tables of 

Fish Entrainment at Hydropower Projects 

principal components. We present details of 

this analysis in Appendix 3. 

All the variability in the data set can 

be explained by three principal components. 

This result is expected because the 

correlation analysis showed close correlation 

between many independent variables. The 

principal components table for the flowadjusted entrainment rate and the same 11 

physical variables shows a very similar 

distribution (or accounting) of the variability 

in the first three principal components. 

Although these three principal components 

accounted for all the variability in the data 

set, they cannot be used to predict 

entrainment rates at other sites. 

Regression Analysis 

As discussed"" previously, the 

exploratory analyses of average entrainment 

;md flow-adjusted entrainment rate for eight 

univariate analyses yielded no strong, 

consistent trends. 

We further explored these 

interrelationships with some additional 

approaches. We reviewed the species 

composition data and segregated the 42 sites 

with this type of data into 6 species 

assemblages. The assemblages are based on 

the species that accounted for 10 percent or 

more of the species composition entrained at 

each site. Some species assemblages were 

indicative of particular habitat types (these 

habitat types are in parentheses). 

1. " Clupeid dotftinated sites - Station 26, 

Y oughiogheny, Beaver Falls, 

Greenup, Buzzard's Roost, Lock & 

Dam #2, King Mill, and Hawks Nest. 

We could not distinguish all sites 

where most entrainment occurred 

during the winter, because some sites 

did not have species composition or 

Page 3-25 
2. 

3. 

4. 

5. 

entrainment abundance sampling in 

the winter season. This may be 

important because in the winter, 

moribund fish may inflate 

entrainment, as suspected at 

Buzzard's Roost and Youghiogheny. 

Ictalurid, white sucker, darter, 

American eel (benthic species 

assemblage) Wisconsin River 

Division, Centralia, 99 Islands, Dam 

4, Foote, Tower, and Gaston Shoals. 

Walleye, yellow perch, black crappie, 

smallmouth bass (offshore species 

assemblage) - Cooke, Rogers, Mio, 

Hardy, Kleber, Escanaba 1, Brule, 

Crowley, Abbeville, French Landing, 

and Rothschild. 

Rock bass (near-shore, hard substrate 

species assemblage) - Alcona, Loud, 

Five Channels, and Park Mill. 

Lepomis, cyprinids (near-shore 

soft/ sandy substrate species 

assemblage) - Croton, Moores Park, 

Prickett, Shawano, Saluda, Hollidays 

Bridge, Millville, Constantine, White 

Rapids, and Thomapple. 

6. Salmonid dominated sites- Buchanan 

and Escanaba 3. 

Because assemblage 6 is not represented by 

enough sites to be a separate covariate for 

the analysis, for our analysis we merged it 

with assemblage 5 (the remaining species at 

these sites and the habitat is most similar to 

that of assemblage 5). Also, although the 

Upper, Lower and Pixley sites did not 

report species composition data, these sites 

probably would be most like Crowley, and 

we included them in assemblage 3. 

Page 3-26 

We used these assemblages as blocks 

or covariates in a reanalysis of our previous 

exploratory data analysis. This analysis 

does not drop outlier sites but adjusts the 

means of the groupings as covariates. The 

output of the analysis yields an average 

entrainment and flow-adjusted entrainment 

rate for each assemblage and a test to 

quantify a regression against the 11 physical 

variables. 

We used the JMP (SAS, 1989) 

analysis platform "Select Model" to develop 

a regression analysis of one of the two 

dependent entrainment rates (average 

entrainment or flow-adjusted entrainment 

rates) against the assemblage code and one 

additional independent variable among the 

11 physical variables used for both the 

correlation and principal components 

analysis. We also developed a larger model 

for both entrainment rate variables using the 

two or three independent variables that were 

most highly correlated with the average 

entrainment and flow-adjusted entrainment 

rates. We evaluated the value of these 

higher order models compared to the simple 

covariate models. We present details of this 

analysis in Appendix 5. 

For the flow-adjusted entrainment 

rate, we observed statistically significant 

responses for average river flow, reservoir 

size, total storage, usable storage, and 

trashrack spacing. There also was a 

marginally significant response for reservoir 

flush rate. The statistical significance of 

some of these regression tests is at least 

partly attributable to outliers in the data set. 

The multiple variable model is not justified 

to explain and summarize the available data 

over the use of the simple single variate 

models with the assemblage covariate. 

Fish Entrainment at Hydropower Projects 
For the total average entrainment rate, 

we observed statistically significant 

responses for reservoir size, total storage, 

usable storage, and trashrack spacing. 

Again, the statistical significance of some of 

these regression tests is partly attributable to 

high-leverage observations in the data set. 

The multiple variable regression with 

average velocity, trashrack spacing, and 

reservoir length was not statistically 

significant for any of the individual variables 

in this combination of independent regressors, even though the correlation analysis 

showed that these variables correlated with 

the average entrainment rate. The multiple 

variable model was not justified by the 

observed results. 

Although the species assemblage 

variable improves the predictive ability of 

the single variable models, the variability is 

still high. Even the average entrainment 

rate is very variable within the species 

assemblages depending on the presence of 

the specific observations in the data set. 

Conclusions of Supplemental Analyses 

Although entrainment rates vary 

among the sites, this variability is not well 

explained by physical parameters or species 

composition. There are some broad 

associations in entrainment rates for groups 

of related variables, but these do not 

necessarily indicate a cause-effect 

relationship. Also, the data set we used is 

limited in size and includes a number of 

sites with entrainment rates that are 

considerably greater or less than those 

observed from other sites with similar 

species composition and physical conditions. 

The data set also contains some groups of 

sites with relatively similar entrainment 

rates, physical conditions, and species 

assemblages. 

Fish Entrainment at Hydropower Projects 

From these analyses we conclude that 

the available data cannot be used to produce 

quantitative and statistically significant 

trends between total entrainment rates and 

evaluated variables. This does not, 

however, necessarily preclude estimating 

entrainment rates at unsampled sites. 

3.2.6 Analysis of Monthly Trends of 

Representative Species 

Although there were no definitive 

trends in the statistical trend analysis using 

total annual entrainment rates, there may be 

species-specific monthly trends. We plotted 

the monthly entrainment rate for 

representative species for sites within 

watersheds with more than two entrainment 

studies included in the database. Any 

monthly species-specific trends were 

considered most likely to be evident within 

the same watershed. Species-specific 

monthly entrainment rates for additional 

sites were considered as warranted by the 

base analysis. Because, for clupeids, 

monthly entrainment data were only 

available for a limited number of projects, 

we presented all available monthly data 

regardless of watershed location. 

Smallmouth Bass 

Figure 3-6 shows the monthly 

entrainment rate of smallmouth bass within 

the two Michigan drainage basins. 

Smallmouth entrainment, which occurs 

between May and October, is generally less 

than two fish/hour. Entrainment rates of 

smallmouth bass increased in October at the 

Muskegon River sites and at Cooke and 

Foote on the Au Sable River. This is most 

likely attributable to increased mobility of 

young-of-the-year. There was no such 

increase at the other four Au Sable River 

sites. The only available parameter that 

distinguishes Cooke and Foote from the 

Page 3-27 
-

a: 

J: 

J: -

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u: 

-

w 

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w 

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::: 

z 

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7 

6 

5 

4 

3 

2 

1 

1.60 

1.40 

1.20 

1.00 

0.80 

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0.40 

0.20 

I 

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u. 

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0. 

< 

0.00 tt: ~~ 

c: .0 C6 ctl C1> ""'") u. ~ 

Figure 3-6 

MONTH 

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> 0 

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0 

0 

0 

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> 0 

z 

Au Sable River 

--11-- Alcona 

---o--- Cooke 

---+--Foote 

--<>--Loud 

--a-- Mio 

-fr-- Five Channels 

Muskegon River 

--11-- Croton 

-::t-- Rogers 

----+--Hardy 

0 

C1> 

0 

Smallmouth Bass Entrainment at Michigan Sites 

Page 3-28 Fish Entrainment at Hydropower Projects 
other Au Sable River sites is that the size of 

both reservoirs (1,800 acres) is 725 acres 

larger than any of the other reservoirs in 

this basin. The Muskegon River sites do 

not have uniformly large reservoirs, 

however, reservoir size does not seem to be 

related to the fall peak of smallmouth bass 

entrainment rates. Other than the fall trend ' there is no consistency in entrainment rate; 

entrainment rates increase at some sites as 

they decrease or remain the same at other 

sites. 

Seasonal trends in the entrainment 

rate of smallmouth bass were more 

consistent at the Wisconsin sites (Figure 3-7) 

where most entrainment occurs between 

May and October. There is a uniform peak 

in entrainment rates at all three sites in 

June, however, that may correlate with 

increased movement of juveniles and adults 

to preferred habitat. The magnitude of the 

peak is dramatically different: 0.37/hour at 

Brule, 1. 75/hour at White Rapids, and 

27.3/hour at Wisconsin River Division. 

(The mesh in the rear half of the net used at 

Wisconsin River Division was smaller than 

the other two sites, which probably resulted 

in the collection of more small fish.) The 

depth to the top of the intake is 22 feet at 

Brule, 7.5 feet at White Rapids, and 0 feet 

at Wisconsin River Division, which suggests 

that deeper intakes may exclude smallmouth 

bass in June. 

To. further explore this relationship, 

we exammed monthly entrainment rates at 

two additional Wisconsin sites, Shawano and 

Crow ley. There was a slight peak in the 

June smallmouth entrainment rate at both 

sites (0. 30/hour and 0. 80/hour, 

respectively). The depth to the top of the 

intake at both of these sites was 3 feet. A 

cause-effect relationship between intake 

depth and smallmouth bass entrainment rates 

cannot be determined conclusively based on 

Fish Entrainment at Hydropower Projects 

the limited data. Another peak in 

smallmouth entrainment rates occurred in 

September at the Menominee watershed sites 

as well as at Shawano, possibly 

corresponding to the increased vulnerability 

of young-of-the-year. There was no 

increase at Wisconsin River Division or 

Crowley. 

In general, seasonal peaks in 

smallmouth entrainment rates may be 

predicted at some sites. The magnitude of 

such peaks, however, appears to be 

unpredictable. 

Walleye 

There · is no consistent trend in 

monthly entrainment rates of walleye at the 

Michigan sites either in seasonality or 

magnitude (Figure 3-8). There is some 

increased entrainment during the spring at 

some sites, which may be an artifact of 

tailrace intrusion of adults into the partialflow tailrace nets. 

Entrainment rates of walleye at three 

of the four Wisconsin sites in the 

Menominee and Wisconsin River basins 

peaked during June. A fourth site (Brule) 

showed a distinct peak during July (Figure 

3-9). Two of the four Wisconsin sites 

exhibited a minor peak during October, 

probably corresponding to increased 

vulnerability of young walleye due to die-off 

of vegetation that keeps young fish in 

nursery areas. The magnitude of the 

June/July entrainment rate peaks at Park 

Mill, Brule, and Rothschild, ranging from 

4.40 to 5. 30 walleye/hour seem consistent. 

A review of late spring/early summer 

walleye entrainment rates at other Wisconsin 

sites showed much greater variability. At 

Thornapple, the peak entrainment rate (in 

May). was 1.1 fish/hour and the peak 

entrainment rate at Crowley (in June) was 

16.7 fish/hour. 

Page 3-29 
1.80 

a: - 1.60 ~ :c 1.40 (/) 

u: 

- 1.20 w 

..... 

< 1.00 a: 

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z 0.80 

w 

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z 

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c 

ctl 

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< 

c:: 15 

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a: 

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ctl Q.l ..., u. 

.0 

Q.l 

u. 

ca .... 

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I: 

ca .... 

c. ~ < 

Figure 3-7 

>. 

ctl 

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• 

>. c 

ctl "3 c. ::J Ol 

~ ..., ..., ::J Q.l 

< C/) 

MONTH 

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c 

::J ::J 0> c. -0 ..., ..., ::J Q.l 0 

< C/) 

MONTH 

D--::J 

0 > 0 

0 0 Q.l 

z Cl 

• • 

> 0 

0 Q.l 

z Cl 

Menominee River Watershed 

--•-- White Rapids 

-D-- Brule 

-D-- Wisconsin River 

Division 

--+-- Crowley• 

(Flambeau River) 

• Shawano· ..___ ___ (Wolf River) __ _, 

·suPPLEMENTALSITES 

Smallmouth Bass Entrainment at Wisconsin Sites 

Page 3-30 Fish Entrainment at Hydropower Projects 
8 T - 1 Au Sable River a: 7 J: .._ 

J: 

CJ) • Alcon a 6 u:: 

-

w 5 --o--- Foote 1-

< a: 4 --+--Loud 1-

z 

w 3 :E 

I 

-----o------ Mia 

z 

< 2 I a: Five Channels 1-

z 1 w I 

0 ~ 

c: .0 Ctl co Q) 

.... 

a. co 

>.. c: 

:::::1 3 Ol -a. 0 > 0 

' u.. ~ <( ~ ' ' :::::1 Q) 0 0 Q) 

<( CJ) z 0 

MONlH 

9 

1 -a: 8 J: .._ 

J: 

CJ) 7 Muskegon River 

u:: 

-

w 6 

1- -------- Croton < 5 a:: 

1- 4 -o--- Rogers z 

w 

:E 3 ---+--Hardy z 

< a:: 2 

1-

z 

w 

0 ~'----11--------~ .0 ffi .... >.. c: Q) a. co :::::1 3 Ol -a. -0 > 0 

u.. ~ < ~ ' ' :::::1 Q) 0 0 Q) 

<( C/) z 0 

MONlH 

Figure 3-8 

Walleye Entrainment at Michigan Sites 

Fish Entrainment at Hydropower Projects Page 3-31 
1 8 ~ 

-

a: 1 61 

:I: 

141 :I: --

en 

u:: 

- 1 2 w 

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a: 

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ct • 

Menominee River Watershed 

• Pari< Mill 

· -:J-- White Rapids 

--.--Brule 

::I Ol -a. -0 > 0 

J ::I Q) 0 0 Q) 

< CJ) z Cl 

MONlli 

• 

Wisconsin River 

• Rothschild 

~ 1- _/ 

ffi 0 .___.,---..~~~.~--~! --~---~+.---+.--~:--=11--~·~---· 

Page 3-32 

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MONlli 

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Walleye Entrainment at Wisconsin Sites 

Fish Entrainment at Hydropower Projects 
We compared the physical 

characteristics of the two sites with 

comparatively high June/July entrainment 

rates, White Rapids and Crowley, to those 

with much lower peak walleye entrainment 

rates. The trashrack spacing at White 

Rapids and Crowley was 2.4 to 2.5 inches, 

whereas at Brule, Rothschild, and 

Thornapple the trashrack spacing was 1.4 to 

1. 7 inches, suggesting that the narrower 

spacing of trashracks may correlate to the 

lower entrainment rates. This relationship is 

not evident at the Park Mill Project, which 

has trashrack spacing of 3.0 inches, but 

walleye entrainment rates comparable to 

Brule and Rothschild. 

Black Crappie 

Entrainment of black crappie at 

Michigan sites generally increases after 

March and decreases after November 

(Figure 3-1 0). Within this time frame, there 

are peaks at some sites (i.e., there are 

entrainment rate peaks in June and 

November at Cooke, Croton, and Hardy) 

but little discernable peaks at the other 

Michigan sites. A review of limited 

physical characteristics of these plants 

reveals no apparent reason for these intersite 

differences. The entrainment rate of black 

crappie was also inconsistent at two other 

Michigan sites, Prickett and French 

Landing. At Prickett, the black crappie 

peak entrainment rate occurred during April 

(35. 7 /hour) while at French Landing (where 

over 75 percent of entrained fish were black 

crappie), peaks in total entrainment occurred 

in July (774.4/hour) and November 

( 610. 2/hour). 

The peak black crappie entrainment 

rate noted at some Michigan sites in June 

seems to shift to July or August at most of 

the sites in the Wisconsin River and 

Menominee basins (Figure 3-11). There 

Fish Entrainment at Hydropower Projects 

were minor peaks at some Wisconsin sites 

during October (White Rapids) and 

November (Wisconsin River Division), but 

too few black crappie were collected at Park 

Mill to reveal any trends at this site. The 

peak summer entrainment rate at Rothschild 

(33.4 fish/hour) is approximately four times 

greater than at the other two sites on the 

Wisconsin River. The most obvious 

difference between these sites is the size of 

the Rothschild impoundment, which is more 

than six times larger than the other two 

impoundments. 

We compared black crappie 

entrainment at sites within the Broad River 

watershed in the southeast with midwestern 

sites to look for similar trends. At all three 

sites with more than incidental black crappie 

entrainment, there was a fall peak (Figure 3-

12), most likely reflecting increased 

vulnerability of young fish. This peak 

occurred during September and October at 

Hollidays Bridge, during October and 

November at Ninety-nine Islands, and 

during November at Saluda. These fall 

peaks appear analogous to the fall peaks 

noted at midwestern sites. 

At Hollidays Bridge there was a 

winter peak during December and January, 

but not at the other two sites. The intake of 

the Hollidays Bridge Project is 19 feet deep, 

but only 13 and 8 feet deep at Saluda and 

Ninety-nine Islands. This deeper intake may 

favor entrainment of fish during periods of 

relative inactivity and cooler water 

temperatures. 

Yellow Perch 

There were few consistent trends in 

entrainment of yellow perch at most sites in 

the Au Sable watershed (Figure 3-13). 

Spring and fall peaks were evident at Cooke 

and a slight peak in April at Alcona and 

Page 3-33 
a: -

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Page 3-34 

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0 

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> 0 

z 

> 0 

z 

0 

Q) 

0 

• 

0 

Q) 

0 

Au Sable River 

• Alcona 

--D-- Cooke 

--+--Foote 

----<>----- Loud 

--.-- Five Channels 

Muskegon River 

• Croton 

--o--- Rogers 

--+--Hardy 

Black Crappie Entrainment at Michigan Sites 

Fish Entrainment at Hydropower Projects 
1 2 

-

a: 0 :I: 1 0 

:I: --

en Menominee River u: 

- 8 w 

1-

<( ----- Park Mill 

a: 6 1- 1 z ----o----- White Rapids 

w 

:!: 4 z 

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0 c: .0 ffi .... >. c: "5 - - (.) C'CS Q) c.. C'CS ::l Cl c.. (.) > ~ ~ J ::l Q) 0 0 Q) J u.. ~ J ~ (/) z 0 

MONTH 

35 

• -

a: 

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::c 

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u:: 25 - ----- Rothschild w 

1-

<( 20 --o-- Wisconsin River a: 

1- Division z 1 5 

w 

::!: 

z Centralia 1 0 

<( 

a: 

1-

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w 

0 ~==--A..._,---..!r-!0 ~ 

c: .0 ffi .... >. c: C'CS Q) c.. C'CS ::l "5 Cl -c.. -(.) > (.) 

~ J ::l Q) 0 0 Q) J u.. ~ ~ J ~ (/) z 0 

MONTH 

Figure 3-11 

Black Crappie Entrainment at Wisconsin Sites 

Fish Entrainment at Hydropower Projects Page 3-35 
c:-12aT 

~ . T ~ 1.6 I ~ 1.4 t ~ 1.2 

c: 1 ...... 

z 

~ o.a T ~ 0.6 

< 

c: 

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z 

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Page 3-36 

c 

ctl 

--, 

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Figure 3-12 

MONTI-i 

Ol -a. ::l Q.l 

< (/) 

-0 

0 

> 

0 

z 

0 

Q.l 

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Broad River Watershed 

• 99 Islands 

--D---- Holliday's Bridge 

---.-- Saluda 

Black Crappie Entrainment at South Carolina Sites 

Fish Entrainment at Hydropower Projects 
1 4 -r 

-

a: 

:I: 1 2 

:I: --

en 

u: 1 0 -

w 

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a: 

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a: 

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0 

Yellow Perch Entrainment at Michigan 

Fish Entrainment at Hydropower Projects 

> 0 

z 

> 0 

z 

0 

Q) 

Cl 

0 

Q) 

Cl 

Au Sable River 

----- Alcona 

--c- Foote 

--+--Cooke 

-o-- Loud 

--.-- Mio 

-C:r--- Five Channels 

Muskegon River 

-----Croton 

-o--- Rogers 

--+--Hardy 

Page 3-37 
Five Channels. In contrast, the pattern at 

Croton and Hardy on the Muskegon River 

showed a peak in June and August, with a 

minor peak at Hardy in November. 

There was a major peak in 

entrainment rates at Brule and White Rapids 

in June and/or July (Figure 3-14), with a 

secondary peak at both sites in October. 

The average size of yellow perch at Brule 

was 1.2 inches and at White Rapids, 2.0 

inches, suggesting that nearly all yellow 

perch entrained at these two sites were 

young-of-the-year. 

Entrainment rates at Buzzard's Roost 

were substantially greater than at any other 

site in the database (Figure 3-15). After the 

peak entrainment rate (86.4 fish/hour) in 

April, numbers declined substantially. 

Saluda was the only other site within the 

Broad watershed at which yellow perch 

comprised more than an incidental portion 

of the entrainment catch. There was no 

entrainment sampling by net at Saluda 

during March, April, and May, and, 

therefore, it is not possible to determine if 

this spring peak also occurred here. 

Monthly entrainment rates were plotted for 

Abbeville, which is in proximity to the 

Broad watershed, as a supplemental analysis 

to assess whether the spring peak at 

Buzzard's Roost was an anomaly. Abbeville 

showed a spring peak in March rather than 

April, but the magnitude of the peak at 

Abbeville was a third of that at Buzzard's 

Roost. The only other southern site at 

which yellow perch were collected was King 

Mill. Monthly data at this site reveal a very 

slight peak in March (1.1 fish/hour) 

although sampling was not conducted in 

January or February. 

In general, peak entrainment rates of 

yellow perch vary in different regions. The 

magnitude of peak entrainment events also 

Page 3-38 

varied, except for the June/July peak at 

White Rapids and Brule. 

White Sucker 

The estimated entrainment rates for 

white sucker at the Michigan sites on the Au 

Sable and Muskegon rivers were strongly 

influenced by the intrusion of fish into the 

partial-flow tailrace nets, especially during 

the localized spring ·spawning migration. 

Most fish collected were more than 10 

inches long, much larger than most fish 

collected with full-flow nets. Because of 

this intrusion, monthly entrainment rates 

presented in Figure 3-16 should be 

interpreted cautiously. 

Entrainment rates of white sucker at 

the two Menominee watershed sites, Brule 

and Park Mill, were never higher than 0.6 

fish/hour (Figure 3-17). There was a peak 

at Brule during June, comprised mostly of 

fish believed to be 1 year old based on 

monthly size distribution data. There are no 

other trends in white sucker entrainment 

rates. 

Clupeid.s 

Because clupeids normally travel in 

dense schools, sometimes they can be 

entrained in high numbers. As previously 

discussed, clupeid entrainment is often 

episodic (e.g., alewife entrainment at the 

Youghiogheny Project). Monthly 

entrainment rates for gizzard shad and 

threadfm shad are discussed in the following 

section (monthly data for other clupeids are 

not readily available). Entrainment was 

generally dominated by young fish from 1.5 

to 4.0 inches in length, but in some cases 

included fish up to 14 inches in length. 

Fish Entrainment at Hydropower Projects 
12 I -

a: 

:::c 1 0 ..._ 

:::c 

en 

u:: 

-

w 8 

Menominee River Watershed 

1-

< a: 6 1-

• White Rapids 

z 

w -D-- Brule 

:E 4 z 

< a: 

1- 2 z 

w 

0 

.0 ~ .... >. c: Q) 0.. ctl :::1 :::1 Ol 0.. () > () 

LL ~ < ~ ..., ..., :::1 Q) 0 0 Q) 

< en z 0 

MONTH 

Figure 3-14 

Yellow Perch Entrainment at Wisconsin Sites 

Fish Entrainment at Hydropower Projects Page 3-39 
90 

-a: 80 J: 

.._ 

J: 70 en 

u:: 

-

w 60 ~ 

< 50 a: 

~ 

z 40 

w 

:E 30 z 

< a: 20 ~ 

z 

w 1 0 

0 

c: 

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~:~I 55 70 I 

u:: 

w - 60 

1-

< 50 a: 

!z 40 

w 

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/ 

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Cl> 

LL. 

Saluda River 

• Buzzard's Roost 

----D- Saluda 

::--o----,_"""'--:: --=0 

ffi .... >.. c: a. ctl ::I "5 Ol -a. 0 > 0 ~ < ~ J J ::I Cl> 0 0 Cl> 

< en z Cl 

MONTH 

Rocky River 

--11-- Abbeville 

• 

{ 0 --~---- ~ • • • • • 11!1 

Page 3-40 

c: 

ctl 

J 

.D ffi .... Cl> >.. c: :; a. ~ a. ctl ::I Ol 0 > 0 LL. < ~ J J ::::J Cl> 0 0 Cl> 

< Cl) z Cl 

MONTH 

Figure 3-15 

Yellow Perch Entrainment at South Carolina Sites 

Fish Entrainment at Hydropower Projects 
20 

- 1 8 

0 

a: 

J: 

J: -- 1 6 Au Sable River UJ 

u:: 1 4 -

w • Alcon a 1- 1 2 

< a: 1 0 ---G-- Foote 1- t z 

w 8 ~ ---+-- Mio 

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<( (f) z 0 

MONTH 

6 

1 \ -

a: 

J: 5 -- Muskegon River :X: 

UJ 

u:: • - 4 w --11-- Croton 

1-

<t 

a: 3 --D-- Rogers 1-

z 

w 

._/._/ ~ 2 ---+-- Hardy z 

<: 

a: 

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0 

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LL. :E <( :E ...., ...., ::;! Q) 0 0 Q) 

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MONTH 

Figure 3-16 

White Sucker Entrainment at Michigan Sites 

Fish Entrainment at Hydropower Projects Page 3-41 
1i? 0.60 I ~ 0.50 

en 

u:: 

~ 0.40 

1-

<( 

c:: 

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w 

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0.10 t 

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Figure 3-17 

0> 0.. (.) 

:;) Q) 0 

<( (/) 

MONTH 

> 

0 

z 

Menominee River Watershed 

(.) 

Q) 

0 

• Park Mill 

--o- Brule 

White Sucker Entrainment at Wisconsin Sites 

Page 3-42 Fish Entrainment at Hydropower Projects 
The most prevalent seasonal trend in 

gizzard shad entrainment at many sites is the 

fall (usually October and/or November) peak 

in abundance (Figures 3-18 and 3-19). This 

peak is quite pronounced at some sites: 25. 8 

fish/hour at Hawks Nest; 49.6 fish/hour at 

Lock and Dam No. 2; and 5,930 fish/hour 

at Greenup Lock and Dam (the latter was 

not graphed because of the relative 

difference with other sites and there were 

only two other data points for the year). 

These three sites each have average river 

flows in excess of 9,000 cfs. 

The remaining six sites with enough 

entrained gizzard shad to evaluate have 

average river flows of less than 2,500 cfs. 

There is no fall peak at Croton, Gaston 

Shoals, or King Mill; at Saluda peak 

entrainment begins in November but 

continues at least through February (Figure 

3-19). Hollidays Bridge has a similar but 

less pronounced cool weather increase in the 

entrainment rate during December and 

January. 

Entrainment of gizzard shad during 

the spring and summer generally ranged 

from 0 to 6.9 fish/hour with the exception 

of Greenup Lock and Dam, where the 

spring rate was 86.3 fish/hour. Greenup 

also illustrates the temporal variability that 

is frequently evident in clupeid entrainment 

rates, as none were collected in the summer 

sampling effort. Lock and Dam No. 2 also 

shows temporal variability with monthly 

entrainment rates from December to August 

varying from 0 to approximately 4 

fish/hour. 

Threadfm shad were only represented 

at sites in South Carolina and Georgia 

(Figure 3-20). The entrainment rate of 

threadfm shad at Buzzard's Roost is dramatically greater than any other site or any 

other species, with the maximum rate of 

Fish Entrainment at Hydropower Projects 

13,622 fish/hour occurring in February. 

The high winter entrainment rates are 

inconsistent across sites; winter peaks may 

be due to low water temperature stress. 

Most sites exhibit a spring peak in entrainment of clupeids. The Buzzard's Roost 

impoundment ( 11,404 acres) is larger than 

any other impoundment included in the 

database except Lock and Dam No. 2, 

which is 11,810 acres. 

3.2. 7 Size Composition Assessment 

Evaluating the size of entrained fish is 

complicated by variable approaches to 

reporting this information (see discussion in 

Section 3.2.1). In general, however, mostly 

small fish are entrained. We assessed the 

size of entrained fish at each site by 

establishing three groupings: sites strongly 

dominated by small fish (75 percent or more 

of the entrained fish are 4 inches or less); 

sites strongly dominated by small to 

moderate sized fish (75 percent or more of 

the entrained fish are 6 inches or less); and 

sites with variable-sized fish (the remaining 

sites). We evaluated size of entrained fish 

for 40 of the 45 sites included in the 

database. 

Twelve sites were dominated by small 

fish (Table 3-5). We included three sites in 

this category based on hydroacoustic target 

strength data (Tower, Kleber, and White 

Rapids), even though net-derived sizedistribution data indicate that these sites 

have more variable- (Tower) or moderatelysized fish. (The executive summaries for 

the studies at these three sites presented only 

the hydroacoustic size distribution, so we 

concluded that these data are more 

representative.) Eleven sites were 

dominated by small to moderate-sized fish, 

and 17 sites had more variable-sized fish. 

Of the 17 sites in the latter category, 

however, 10 are based on size distribution 

Page 3-43 
Page 3-44 

c 

ctl 

J 

..0 

Q) 

LJ.. 

Figure 3-18 

c 

::l 

J 

MONTH 

• 

a. (.) 

Q) 0 

(/) 

> 

0 

z 

(.) 

Q) 

0 

--11-- Lock + Dam #2 

(Mississippi River) 

~Croton 

(Muskegon River) I 

-----+-- Hawks Nest I 

"-------(New River)~ 

Gizzard Shad Entrainment at Midwestern Sites 

and West Virginia 

Fish Entrainment at Hydropower Projects 
-

c: 

:::c ._ 

:z: 

en 

u::: 

-

w 

1-

< 

a: 

1-

z 

w 

~ 

z 

<( 

a: 

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1 8 

1 6 I 

1 4 

1 2 

1 0 

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6 /~ 

:~~ \ c .0 ~ ttl Q) 

.... 

a. ttl 

>. c 

::l ::l Cl -a. -:> u... ~ < ~ -:> -:> ::l Q) 

< (/) 

MONlli 

Figure 3-19 

• 

-0 > 0 

0 0 Q) 

z 0 

Broad River Watershed 

and 

Savannah River 

• 99 Islands 

(Broad River) 

-o-- Gaston Shoals 

(Broad River) 

----+-- Holliday's Bridge 

(Saluda River) 

----<>- Saluda 

(Saluda River) 

-.....-- King Mill J ,___ ___ (Savannah River) 

Gizzard Shad Entrainment at Southeastern Sites 

(Georgia and South Carolina) 

Fish Entrainment at Hydropower Projeas Page 3-45 
-

a: 

:I: 

:I: 

(/) 

-

u:: 

-

w 

1-

< a: 

1-

z 

w 

:E 

z 

;;: 

a: 

1-

z 

w 

Page 3-46 

14 T 

:: 1 

8 -

6 

• 

--- 99 Islands 

(Broad River) 

--G-· - King Mill 

(Savannah River) i 

4 

2 

0 l ~~ ~~ 

--+-- Abbeville] L----- (Rocky River) 

c:: .0 ffi ctl (l) 

J u. ~ 

14000 I . 

112000 r/ ~ 1 oooo I 

~ 8000 • 

a: 

~ 6000 

w 

:E 

.... >. c:: a. "5 ctl :J J <( ~ J 

MONTH 

z 4000 

< a: 

~ 2000 il-ll""' w 

~ • 0 

ffi .... >. c:: a. "5 ctl :J ~ <( ~ J J 

MONTH 

Figure 3-20 

.... Ol a. -0 > 0 

:J (l) 0 0 (l) 

<( (f) z 0 

Saluda River 

• Buzzard's Roost 

.~ ~ ~ .... Ol a. 0 > 0 

:J (l) 0 0 (l) 

<( (f) z 0 

Threadfm Shad Entrainment at Southeastern Sites 

(Georgia and South Carolina) 

Fish Entrainment at Hydropower Projects 
TABLE3-5 

PREDOMINANT SIZE OF ENTRAINED FISH 

AT SITES INCLUDED IN THE DATABASE 

Sites Dominated by Small Sites Dominated by Small Sites Dominated by 

Fish to Moderate Sized Fish Large Fish 

(L15% .5_4.0 inches) (L15% ..$_6.0 inches) (all remaining sites) 

Tower (89 %- HA) Escanaba Dam 3 (75%) Alcona* 

Kleber (95 %- HA) Thomapple (80%) Foote* 

Prickett (84%) King Mill (95% )* Cooke* 

Park Mill (79% )* Brule (86%) Loud* 

Crow ley (78%) Escanaba Dam 1 Mio* 

White Rapids (82 %- HA) Shawano Five Channels* 

Centralia (97%) Abbeville* Croton* 

Rothschild Greenup Lock and Dam* Rogers* 

Wisconsin River Division Station 26 Hardy* 

Youghiogheny Buchanan* Moores Park 

Hawks Nest* Constantine French Landing* 

Buzzard's Roost 99 Islands 

Gaston Shoals 

Saluda 

Hollidays Bridge 

Dam No.4 

Millville 

* All or part of the entrainment estimate derived from partial flow netting. 

Note: All size characterizations based on netting data unless marked by "HA" (for hydroacoustics). 

When readily calculated, size percentages indicated in parenthesis; otherwise, size categorizations 

based on best available evidence. 

Fish Entrainment at Hydropower Projects Page 3-47 
infonnation data derived from partial-flow 

tailrace netting. This method may 

overestimate the presence of larger fish 

because of tailrace intrusion. 

We did not detect from our analysis a 

relationship between trashrack bar spacing 

and size of entrained fish. However, one 

would expect that fish wider than the 

trashrack clear bar spacing would be 

excluded from entrainment. Bar spacing at 

Moores Park is 1.62 inches and at Dam No. 

4 is 1.25 inches; both of these sites 

entrained relatively large fish based on fullflow tailrace netting. 

Tower has the smallest trashrack 

spacing of all projects included in the 

database. The l-inch trashrack in place at 

this site is frequently recommended as an 

entrainment protective measure. If this 

trashrack successfully excludes larger fish, 

then the entrainment catch at this site should 

be comprised almost entirely of small fish. 

The trashracks at Kleber have 3-inch 

spacing. The same consultant conducted the 

entrainment studies at both sites. Because 

the methods used at both sites are 

comparable, we can assess the influence of 

trashrack width on the size of entrained fish. 

There were some differences in the relative 

abundance of species entrained at the two 

sites (darters were dominant at Tower), 

however, which may have a bearing on the 

size composition of entrained fish. The 

hydroacoustic target size of entrained fish at 

Tower indicated that 89 percent were less 

than 3.9 inches. At Kleber, however, the 

target size data indicated that more smallersized fish (95 percent of the total) were 

entrained. 

These results suggest that the size of 

entrained fish was similar at Tower and 

Kleber in spite of the differing trashrack 

spacing. The entrainment rate at Tower 

Page 3-48 

(3.4 fish/hour) was approximately half that 

at Kleber (7.2 fish/hour), although this may 

have been related to differences in species 

composition and trashrack spacing. 

3.3 Comparison of Entrainment to 

Reservoir Populations 

Much of the potential impact of 

entrainment and turbine mortality is to the 

fish community within the impoundment at 

the hydropower project. Many entrainment 

studies contain infonnation on the 

impoundment communities including relative 

abundance of different species within the 

impoundment and several present actual 

population estimates of selected target 

species. Comparing these data to the 

entrainment data provides insight into the 

relationship of entrainment to the potentially 

entrained fish community. 

It often is difficult to compare relative 

abundances and population sizes among sites 

because of different methods used to 

evaluate populations. The relative 

abundance of fish in impoundments on the 

Au Sable and Muskegon rivers used five 

different collection methods (electrofishing, 

fyke nets, seines, gill nets and trap nets); 

relative abundance data for the White Rapids 

impoundment were obtained using only fyke 

nets. The Centralia relative abundance data 

are based on electrofishing data. All 

approaches provide useful infonnation, but 

data collected at one site are not necessarily 

comparable to another site because of 

different gear selection, i.e., gear is both 

size-and species-selective. Similarly, the 

population of forage-sized fish ( < 150 mm 

long) at Buzzard's Roost was estimated 

hydroacoustically whereas the other four 

sites at which population estimates were 

available were based on mark and recapture 

studies that focused on fish more than 1 year 

old. 

Fish Entrainment at Hydropower Projects 
Gear selectivity can also bias 

comparisons of relative ot actual abundance 

of species in the impoundments with 

entrainment rates. Partial-flow netting, such 

as at the Au Sable and Muskegon sites, also 

may affect relative abundance accuracy of 

entrainment studies. Tables 3-6 to 3-9 

present comparisons of impoundment 

populations with commonly entrained fish. 

The relative abundance of all species 

of clupeids was consistently greater in 

entrainment samples compared to the 

impoundment populations at both sites where 

data were available. Conversely, the 

relative abundance of brown and black 

bullheads was always greater in the 

impoundments compared to the entrainment 

samples (six comparisons). 

Several species showed trends of 

generally greater relative abundance in . 

entrainment samples compared to their 

respective impoundments. These species are 

channel catfish (3 of 4 comparisons), 

smallmouth bass (6 of 8 comparisons), black 

crappie (7 of 9 comparisons), bluegill (9 of 

13 comparisons), and walleye (8 of 9 

comparisons). The relative abundance of 

minnows was generally greater in 

impoundments than in entrainment samples 

(9 of 15 comparisons). The relative abundance of rock bass at sites on the Au Sable 

River was quite similar at 5 of the 6 sites. 

All of these comparisons are heavily 

influenced by the results of entrainment 

studies that used partial-flow netting, so the 

results probably include intrusion of nonentrained fish. 

It is difficult to show trends beyond 

those indicated due to the limited number of 

studies with comparable data from 

impoundment sampling and entrainment 

sampling with full-flow netting. The species 

composition of entrainment samples is also 

Fish Entrainment at Hydropower Projects 

likely to be affected by site-specific 

characteristics unaccounted for in the 

database (e.g., proximity of the intake to 

high or low temperature sources and/ or 

nursery and spawning grounds). These 

factors may obscure patterns of entrainment 

relative to impoundment populations. 

Population estimates for target species 

are available for the impoundments of five 

projects (Table 3-1 0). Estimates for four of 

these projects (Crowley, Rothschild, 

Wisconsin River Division, and Centralia) 

are based on mark-recapture studies of fish 

at least 1 year old and, for the most part, 

susceptible to being caught by anglers. The 

average size of most entrained fish of these 

target species is 1 to 2 inches. Comparing 

the estimated population to the number of 

annually entrained individuals of that species 

indicates the density of harvestable fish in 

the impoundment that can be achieved in 

spite of the indicated levels of entrainment 

of young fish. 

Entrainment at Crowley was 

dominated by young walleye (23, 311 

individuals; average size: 1.5 inches). The 

impoundment supports an estimated 

population of 19 walleye per acre. 

Population estimates for walleye (all 

harvestable sizes) in both natural lakes and 

hydropower impoundments in Wisconsin 

range from 1. 8 to 48.3 per acre 

(Weyerhaeuser et al., 1993). The density of 

walleye in the Crow ley impoundment 

represents the fifth highest density of all 

reported values. Although annual 

entrainment rates of walleye at the 

remaining three projects was considerably 

less, the density of walleyes in these 

impoundments was lower than that at 

Crowley. 

Page 3-49 
TABLE 3-6 

RELATIVE ABUNDANCE OF DOMINANT SPECIES COLLECTED IN IMPOUND:MENTS 

COMPARED TO ENTRAINED FISH AT PROJECTS ON 1HE AU SABLE RIVER, MJCIDGAN 

Alcon a Foote Cooke Loud Mio Five Channels 

Species Imp. Ent.* Imp. Ent. Imp. Ent. Imp. Ent. Imp. Ent. Imp. Ent. 

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

Spottail Shiner -- 5.6 55.5 -- 5.8 5.8 5.3 (6) 1.6 16.4 -- 16.0 -- (6) (1) (6) (5) (11) (2) (3) 

Emerald Shiner 31.4 - (1) 

Bluntnose 6.1 (5) --

Minnow 

Shorthead 6.6 (5) -- Redhorse 

Golden 14.3 -- Redhorse (3) 

White Sucker 15.1 21.5 -- 48.8 8.3 -- 20.9 15.9 10.4 -- (3) (2) (1) (4) (1) (3) (4) 

Brown Bullhead 3.9 -- 4.4 -- 12.8 -- (4) (4) (3) 

Channel Catfish -- 2.2 

(6) 

Muskelunge -- 9.4 

(3) 

Yellow Perch 28.4 9.6 12.0 1.7 18.9 54.3 16.0 1.6 6.9 2.7 27.6 6.7 

(1) (5) (2) (7) (2) (1) (2) (11) (5) (6) (1) (4) 

Walleye -- 10.7 -- 20.0 -- 26.3 -- 15.9 

(4) (2) (2) (3) 

Rock bass 28.2 26.5 5.3 6.7 6.3 7.2 19.7 39.4 10.1 19.4 25.2 33.3 

(2) (1) (3) (4) (5) (4) (1) (1) (4) (2) (2) (1) 

Bluegill -- 12.4 -- 8.2 -- 8.2 -- 8.3 

(3) (3) (5) (3) 

Pumpkinseed 4.0 -- 8.5 2.2 

(5) (3) (7) 

Black Crappie -- 2.7 8.3 19.5 -- 8.2 

(5) (4) (2) (3) 

' 

Smallmouth 3.9 3.9 -- 11.1 -- 4.9 -- 27.9 -- 21.7 

Bass (5) (7) (3) (5) (1) (2) 

* Relative abundance of entrained fish at all sites on Au Sable River determined by partial flow tailrace netting. 

Note: Only dominant species included; dashes indicate incidental catch; numbers in parenthesis indicate species rank. 

Impoundment populations sampled by electrofishing, fYke net, gill net, seine, and trap net. 

Page 3-50 Fish Entrainment at Hydropower Projects 
TABLE 3-7 

RELATIVE ABUNDANCE OF DOMINANT SPECIES COLLECTED IN 

IMPOUNDMENTS COMPARED TO ENTRAINED FISH AT PROJECTS ON 

THE MUSKEGON RIVER, :MICIDGAN 

Croton Rogers Hardy 

Species Imp. (%)* I Ent. (%) Imp. (%) 1 Ent. (%) Imp. (%) I Ent. (%) 

Sea Lamprey -- 5.8 (4) 

Spottail Shiner 71.5 (1) 3.6 (7) 48.3 (1) 4.7 (11) 0.9 (5) 9.3 (4) 

Emerald Shiner 6.9 (4) 

Golden Shiner 5.2 (5) 

Common Carp 7.1 (3) 

Fathead Minnow -- 7.4 (4) 

Shorthead Redhorse -- 8.3 (3) 

Silver Redhorse 8.1 (2) --

White Sucker 18.2 (2) 14.3 (3) 

Channel Catfish 3.8 (7) --

Yellow Perch 2.8 (3) 14.9 (2) -- 10.1 (2) 68.5 (1) 37.2 (1) 

Walleye -- 6.6 (6) -- 19.8 (2) 

Logperch 2.6 (4) 1.3 (14) 9.0 (3) --

Bluegill 22.6 (2) 34.5 (1) 4.7 (6) 6.0 (8) 1.0 (4) 1.9 (7) 

Pumpkinseed -- 4.5 (5) . Orange Spotted -- 3.9 (6) 

Sunfish 

Black Crappie -- 13.5 (3) 

! 

3. 7 (8) 10.8 (1) -- 9.3(5) 

Smallmouth Bass 0.2 (5) 1.9 (11) -- 6.8 (5) 

* Relative abundance of entrained fish at all sites on the Muskegon River determined by partial-flow 

tailrace netting. 

Note: Only dominant species included; dashes indicate incidental catch; numbers in parenthesis indicate 

species rank. Impoundment populations sampled by electrofishing, fyke net, gill net, seine, and 

trap net. Relative abundance of entrained fish at all sites on Au Sable River determined by partial 

flow tailrace netting. 

Fish Entrainment at Hydropower Projects Page 3-51 
TABLE 3-8 (page 1 of 2) 

RELATIVE ABUNDANCE OF DOMINANT SPECIES COLLECTED IN 

Jl\.IPOUND:MENTS COMPARED TO ENTRAINED FISH AT MISCELLANEOUS 

PROJECTS IN MICIDGAN AND WISCONSIN 

Buchanan Constantine Crowley Centralia White Rapids . 

Species Imp.* Ent. Imp. Ent. Imp. Ent. Imp. Ent. Imp. Ent. 

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

; 

Spotfin Shiner 18.8 6.3 7.4 -- {2) (4) (5) 

Mimic Shiner 25.4 6.3 -- 67.1 

(1) (4) (1) 

Sand Shiner 7.0 2.5 14.2 3.4 

(3) (5) (3) (4) 

Common Shiner -- 25.6 

(1) 

Bluntnose Shiner 21.6 1.9 

(1) (5) 

Emerald Shiner -- 11.5 

(2) 

Common Carp 13.4 -- (2) 

Redhorse 9.6 (2) --

White Sucker 9.6 (3) --

Black Bullhead 26 (2) 4.7 60.5 6.2 

(6) (1) (5) 

Yellow Bullhead 2 (6) 2.3 -- 3.0 

(8) (4) 

Channel Catfish 0.3 7.9 -- 75.3 

(5) (2) (1) 

Chinook Salmon -- 27.5 

(1) 

Rainbow Trout -- 6.9 

(3) 

Northern Pike 5.8 (4) --

Walleye -- 34.8 11.3 -- -- 10.8 

(1) (5) (4) 

Yellow Perch 8 {4) 15.6 5.2 (5) 11.0 

(3) (6) 

Page 3-52 Fish Entrainment at Hydropower Projects 
TABLE 3-8 (page 2 of 2) 

RELATIVE ABUNDANCE OF DOMINANT SPECIES COLLECTED IN IMPOUNDMENTS 

COMPARED TO ENTRAINED FISH AT MISCELLANEOUS PROJECTS IN MICillGAN AND 

WISCONSIN 

Buchanan Constantine Crowley Centralia White Rapids 

Species Imp.* Ent. Imp. Ent. Imp. Ent. Imp. Ent. Imp. Ent. 

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

Blackside Darter -- 4.8 

(5) 

Log Perch 1.6 4.6 10.2 6.0 -- 17.9 

(4) (9) (4) (2) (2) 

Bluegill 15.5 3.5 8 (4) - -- 4.2 -- 13.7 

(2) (3) (3) (2) 

Pumpkinseed 39 (1) 

Rock Bass 1 (7) -- 27.9 

(1) 

Black Crappie 17 (3) 5.7 12.9 1.9 -- 11.3 

(4) (4) (5) (3) . . Smallmouth Bass 13.2 --

* 

Note: 

(3) 

Relative abundance of entrained fish at all sites determined by partial flow tailrace netting. 

Only dominant species included; dashes indicate incidental catch; numbers in 

parenthesis indicate species rank. Impoundment populations sampled by 

electrofishing, fyke net, gill net, seine, and trap net. 

Fish Entrainment at Hydropower Projects Page 3-53 
TABLE 3-9 

RELATIVE ABUNDANCE OF DOMINANT SPECIES COLLECTED IN 

IMPOUND:MENTS COMPARED TO ENTRAINED FISH AT 

MISCELLANEOUS PROJECTS IN OIDO AND GEORGIA 

King Mill Greenup Lock & Darn 

Species Imp. (%) Imp. (%) Ent. 

1984 1990 (%)(1) Imp.(%) Ent. (%)(2) 

(1990) 

Threadfm Shad -- -- 35.4 (1) 

Blueback Herring -- -- 9.1 (3) 

Gizzard Shad -- -- 5.4 (5) 58 (1) 94.0 (1) 

Emerald Shiner -- -- -- 6 (3) 

Spottail Shiner -- -- 12.8 (2) . Golden Shiner 11.7 (4) 5.7 (5) 1.3 (14) 

Common Carp 3 (4) --

River Carpsucker 3 (4) --

Brown Bullhead 1.1 (7) 10.2 (3) --

Chain Pickerel 4.1 (5) 5.7 (5) --

Pirate Perch -- -- 4.9 (6) 

Yellow Perch 14.4 (2) 1.1 (8) 2.7 (7) 

Sauger 3 (4) --

Freshwater Drum 3 (4) 5.0 (2) 

Bluegill 22.0 (1) 34.1 (1) 7.9 (4) 10 (2) --

Redear Sunfish 1.9 (6) 12.5 (2) --

Redbreast Sunfish 14.4 (2) 3.4 (7) 1.5 (12) 

Pumpkinseed -- 6.8 (4) -- . Largemouth Bass 3 (4) --

(1) Relative abundance of entrained fish determined by partial-flow tailrace netting. 

(2) Relative abundance of entrained fish determined by partial-flow turbine gallery netting. 

Note: Only dominant species included; dashes indicate incidental catch; numbers in parenthesis indicate 

species rank. Impoundment populations sampled by electrofishing, fyke net, gill net, seine, and 

trap net. Relative abundance of entrained fish at all sites on Au Sable River determined by partial 

flow tailrace netting. 

Page 3-54 Fish Entrainment at Hydropower Projects 
"Forage Fisb" ! l ' ! 153,600,000 13,470 ' <150mm 

Threadfm Sbad i i 21,558,941 

i ; 

Common Carp 4,058 16.2 872 17 

i (>13") 

Nonbern Pike 154 0.4 0 -- 5,560 3.5 111 (low) 

(11-35") 

Muskellunge 12 <0.1 9 37 

(28-47") 

Walleye 8,004 19 23,311 I 1,567 1.0 7,525 6 3,685 15.3 3,833 12 I 955 3.8 3,020 8 

(3-26") (>12") (>8") (>5") 

BluegiUs 10;571 44.0 179,515 2 

(>2") 

Black Crappie II 12,701 52.9 8,351 7 

(>3") 

Smallmoutb Bass 13,553 56.5 23,762 5 I 1,184 4.7 1,680 II 

(>4") (>4") 

Fish Enrrarnmenl al Hydropower ProJects Page 3-33 

"Forage Fish" ! ! ! i 153,600,000 13,470 

<150mm 

Threadfm Shad i i 21,558,941 

' ~ Common C111p I 4,058 16.2 872 17 

(>13") 

Nonbem Pike 154 0.4 0 -- 5,560 3.5 Ill (low) 

(11-35") 

Muskellunge 12 <0.1 9 37 

(28-47") 

Walleye 8,004 19 23,3ll I 1,567 1.0 7,525 6 3,685 15.3 3,833 12 ! 955 3.8 3,020 8 (3-26") (>12") (>8") ~ (>5") ; 

BluegiUs 10,571 44.0 179,515 2 

(>2") 

Black Crappie II 12,701 52.9 8,351 7 

(>3") 

Smallmoutb Bass 13,553 56.5 23,762 5 I 1,184 4.7 1,680 II 

(>,4") (>4") 

I' uh Enrrammenr at 

Annual entrainment of smallmouth 

bass at Wisconsin River Division (23, 762 

individuals; average size: 1.5 inches) is 

relatively high compared to the relatively 

low rate at Centralia ( 1, 680 individuals). 

The density of smallmouth in the Wisconsin 

River Division impoundment, 56.5/acre, is 

the ftfth highest of the 12 reported values in 

both natural and hydropower waterbodies in 

Wisconsin, as compared to the density of 

smallmouth bass at Centralia ( 4. 7 I acre) 

which ranked eleventh (Weyerhaeuser et al., 

1993). 

The density of black crappie in the 

Wisconsin River Division impoundment is 

roughly in the mid-range of the reported 

values for Wisconsin (Weyerhaeuser et al., 

1993) and the relative abundance of 

entrained black crappie ranked seventh at 

this site (a moderate level relative to the 

other entrained species). 

The remaining population estimate 

data can be compared to the associated 

entrainment values, but the usefulness of 

such comparisons given the previous 

discussion, is limited. There are no 

available data for making intersite 

comparisons of common carp, bluegill, or 

threadfm shad. 

3.4 Summary of Entrainment 

Protective Measure Questionnaire 

Results 

We sent the questionnaire to 

applicants for the 157 sites scheduled for 

license renewal in 1993. We received 

responses on 64 sites. No studies or 

protective were recommended by resource 

agencies at 31 of the sites. We received 

cost information on entrainment and turbine 

mortality studies and/ or protective measures 

for 35 sites, including two not included in 

the original 157. We deleted information 

Fish Entrainment at Hydropower Projects 

for two sites because of ambiguous 

responses. 

Cost information approximates actual 

costs associated with a study or protective 

measure. Conceptual costs (those expected 

to be incurred in the future) are not as 

reliable as actual costs, and the year when 

the cost was incurred or estimated 

introduces additional variability to the 

reported values. The nature of the affected 

resource and degree of resource agency 

intervention also influence entrainmentrelated costs. Site-specific conditions 

strongly influence costs of studies and 

protective measures. 

3.4.1 Summary of Cost Information on 

Entrainment and Turbine Mortality 

Studies 

We received cost figures for 

entrainment and turbine mortality studies for 

12 sites (Table 3-11). We included only 

cost information from fteld studies. We obtained the approximate cost to conduct 

netting studies at Spartan Mills from material in the study report, however, not in 

response to the questionnaire. We supplemented this information with three study 

costs presented in Francfort et al. (1994). 

Costs reflect studies conducted between 

1989 and 1992, with one exception (at 

Leaburg studies were conducted in 1981 and 

1982). 

Netting entrainment studies were 

generally two to four times more costly than 

hydroacoustic studies. Based on six studies, 

the mean cost to conduct hydroacoustic 

studies was $77,820 (range: $50,400-

$105,000). All hydroacoustic studies but 

one (Little Falls on the Mohawk River) were 

supplemented by netting to obtain species 

and size information. Based on seven 

studies, the mean cost to conduct 

Page 3-57 
TABLE 3-11 

ENTRAINMENT AND TURBINE MORTALITY STUDY COST SUMMARY 

Capacity Study Cost 

Site (State) Hydraulic Electrical Years Turbine 

(cfs) (MW) of Study Hydroacoustic Netting Mortality 

Centralia (WI) 3640 3.2 1991-92 $94,093 $393,042 $2,100 

Wisconsin River 5120 1.8 1991-92 105,000 210,000 (1) 

Division (WI) 

Rothschild (WI) 3300 3.64 1991-92 (2) 310,000 10,000 

Brule {WI) 1377 5.3 1990-92 68,000 218,000 (1) 

White Rapids (WI) 5188 8 1990-92 68,000 218,000 70,000 

Chalk Hill (WI) 3500 7.8 1992 (3) (3) 70,000 

Buchanan (MI) 3798 4.1 1991-92 (3) 442,000(4) (1) 

Station 26 (NY) 1800 3 1989-90 50,400 (3) 90,700 (5) 

Station 5 (NY) 5000 38.25 (1995) (3) (3) 139,000 (5) 

Station 2 (NY) 1400 6.5 (1995) (3) (3) 90,700 (5) 

Glen Falls (NY) -- 12.09 1991 (3) (3) 96,000 

Little Falls (NY) -- 13.6 1989-90 81,430 (4) (3) (3) 

Lowell (MA) 6450 15 1990-92 (3) (3) 386,600 (4) 

Spartan Mills (GA) -- 2.05 1991-92 (3) 120,000 (1) 

Leaburg (OR) 2175 13.5 1981-82 (3) -- 51,000 (6) . . ..................................................... -......................................................................................................................................................................................... 

Range of Costs $50,400- $120,000- $2,100-

$105,000 $442,000 $386,600 

Mean Cost $77,820 $273,006 $100,610 

(1) Turbine mortality study costs included in netting costs. 

(2) Studies completed but costs not reported. 

(3) Studies not done. 

(4) Source: Francfort et al. 1994; costs presented as 1993 dollars. 

(5) Projected cost of future studies. 

(6) Escalated to 1992 costs using ENR cost index. 

Note: Respondents for three projects estimated that internal utility costs for managing studies and 

interacting with agencies was approximately $10,000 per year. Consumers Power indicated that 

they spent $1.75 million on entrainment (hydroacoustic supported by netting) and turbine survival 

studies at 11 plants (mean cost:$159,091). 

Page 3-58 Fish Entrainment at Hydropower Projects 
entrainment studies by netting was $273,006 

(range: $120,000-$442,000) and generally 

involved no more than six sampling days per 

month. Field work for all studies lasted 

about 1 year. Cost estimates for four of the 

seven netting studies are for studies done in 

conjunction with hydroacoustics. 

Conclusions based on costs from only five 

hydroacoustic studies and seven netting 

studies should be considered tentative. 

Although hydroacoustic studies may 

be less costly, they often are less acceptable 

to agencies (e.g., resource agencies 

considered the two most expensive 

hydroacoustic studies invalid because of high 

ambient noise). Agencies also dismissed 

results from a hydroacoustic study at 

Rothschild (the cost of which was not 

provided). Agencies considered 

hydroacoustically derived entrainment 

estimates at White Rapids and Brule to be 

less accurate than those derived from netting 

studies. 

Costs associated with turbine 

mortality studies are variable, ranging from 

$2,100 to $386,600. The least expensive 

studies are those conducted as a component 

of entrainment netting studies such as at 

Centralia and Rothschild because almost all 

equipment for testing is already in place. 

Incremental costs of turbine mortality 

studies at these two sites were estimated to 

be $2,100 and $10,000, respectively. 

Similar turbine mortality studies at three 

other sites were not readily separated from 

the cost of the netting studies. 

Turbine mortality also can be assessed 

by marking fish upstream of a powerplant 

and recapturing or counting them at a 

downstream location, a technique that is 

especially effective for outmigrating 

anadromous fish. The Leaburg Project in 

Oregon studied salmon smolts during 1981 

Fish Entrainment at Hydropower Projects 

and 1982, which cost an estimated $40,000 

at that time (nearly $51,000 in 1992 

dollars). Several sites have used a 

promising new approach to assessing turbine 

mortality using balloon-tags that inflate after 

the fish passes through the turbine. Costs of 

balloon-tag studies from three sites (White 

Rapids, Chalk Hill, and Glen Falls) ranged 

from $70,000 to $90,700. Turbine 

mortality study costs for three more sites, 

ranging from $90,700 to $139,000, are 

conceptual and apply to unspecified 

techniques that applicants expect to 

implement in 1995. 

The overall combined cost of 

conducting entrainment and turbine mortality 

studies at each site ranged from 

approximately $51,000 to $489,235. 

Electrical capacity of projects included in 

this assessment ranged from 1.8 to 38.2 

MW. The capacity of all but five singledevelopment projects ranged from 1 to < 10 

MW. Sale et al. (1991) reported study costs 

associated with "downstream fish passage" 

for projects within this capacity range. 

Study costs of the 11 respondents to their 

questionnaire ranged from $5,657 to 

$281,428 with an average cost of $80,047. 

Average total cost of studies at the 10 sites 

within this capacity range reported herein 

(Table 3-11) is $263,003. This considerably 

higher cost may reflect an increase in cost 

of more recently conducted entrainment and 

turbine mortality studies or a difference in 

the nature of study costs provided by 

respondents to the two questionnaires (e.g., 

the DOE report includes assessment of 

bypass efficiency and survival). 

3.4.2 Summary of Cost Information on 

Recommended Entrainment 

Protective Measures 

Costs of entrainment protective 

measures depend on site-specific conditions. 

Page 3-59 
For example, the amount of civil 

engineering needed to install a device has a 

dramatic influence on its cost. The size of 

the river and flow characteristics at the 

project intake substantially influence the 

options for protective devices and the annual 

costs of operation, maintenance, and lost 

generation. 

Management objectives for protective 

devices also have important cost 

implications. If the goal is simply to 

exclude fish from turbine passage, then a 

barrier device may suffice. If downstream 

passage of fish also is a goal, the barrier 

device must incorporate a system to safely 

bypass fish to a downstream location. 

Sale et al. (1991) and EPRI (1986, 

1994a, and 1994b) provide discussions of 

types of entrainment protective measures 

recently installed at sites. Information on 

cost and effectiveness of entrainment 

protective measures was recently compiled 

by the Idaho National Engineering 

Laboratory (INEL) under contract with the 

U.S. Department of Energy (Francfort et 

al., 1994). 

Respondents to the questionnaire 

provided estimates of the constructed cost of 

protective measures for eight sites, and we 

supplemented these data with data from 

seven more sites described in Francfort et 

al. (1994). Conceptual costs for 20 sites 

were provided in response to our 

questionnaire and supplemented by cost data 

for 5 additional sites obtained from study 

reports. Section 4.2 presents the range of 

construction costs for all major categories of 

fish protective systems drawing from 

SWEC' s past and ongoing work in fish 

protective. Cost data summarized below 

represent only the 40 sites where information was obtained from questionnaire 

respondents, study reports, or Francfort et 

Page 3-60 

al. (1994). All sites with summarized data 

are conventional hydroelectric plants (i.e. , 

data were not available for pumped storage 

projects). 

Seven of the projects with installed 

protective measures are located in the 

northeast and reflect the management 

objective of protecting Atlantic salmon 

and/or clupeids from entrainment. A l-inch 

trashrack was installed at the Millinocket 

Pumping Station to prevent landlocked 

Atlantic salmon from being entrained at a 

non-power producing facility, hence a fish 

bypass was not included. The other six sites 

in the northeast incorporated fish bypass 

systems into protective measures. Design 

and construction costs for these seven 

projects ranged from $4,700 to $130,140. 

Another way of looking at costs of 

protective measures is to consider the cost 

per hydraulic capacity of the plant. This is 

a commonly used pricing index, because the 

cost of constructing most protective devices 

is closely related to the flow rate of the 

intake. The cost/cfs for design and 

construction of protective measures for the 

five projects in the northeast for which 

hydraulic capacity was available ranged 

from $9/cfs to $352/cfs, with the lowest 

value associated with the greatest hydraulic 

capacity. Costs presented above are 

substantially lower than those typically 

incurred for protective of anadromous 

species in the Pacific Northwest and 

reflected in the $808/cfs to $1 ,480/cfs 

shown in Table 3-12. 

One questionnaire response provided 

cost information for screening systems 

designed primarily to protect anadromous 

salmonids in the Pacific Northwest, 

including the actual cost for one constructed 

facility and conceptual costs for a second 

facility. Constructed costs were supplied for 

Fish Entrainment at Hydropower Projects 
Desaiption of Protective Consttuction 

Site (State) Measure Costs($) Effectiveness Study Costs ($) 

Millinocket Atlantic salmon 250 None 1988-89 l-inch trasbrack (1) 88,000 352 1 N/A 6,000 (100% effective for salmoo) 

Pumping (landlocked) 

Station (ME) 

Arbuckle Resident and ! 115 0.4 11986-87 Cylindrical wedgewire screens 14,200(3) 78,700 808 3000 N/A S,OOO(conducted over S years); drought bas 

Mountain anadromous j witb air backflusb precluded use by anadromous salmooids. 

(CA)(2) salmon ids 

Wadbams Atlantic salmon 150 0.6 1983 Angled 1-incb bar rack and -- 4,700 31 240 1,944 

(NY)(2) (landlocked) bypass sluice 

Yellowstone Resident species 66 0.9 1992-93 Fisb-s!Dp grale 1,500 6,000 114 

(U1) 

Jim Boyd Anadromous 500 1.2 1985-86 Angled trasb rack; fuclined 0.5- 71,110 621,600 1385 20,000 N/A 

(OR)(2) salmon ids incb fisb screen; bypass weir 

Stillwaler (ME) Atlantic salmon 1700 1.95 1992-93 Fisb bypass weir witb lighting (1) 58,500 34 

and clupeids and 1-incb trasbrack 

Edwanls (ME) Atlantic salmon 3207 3.5 1990 Fisb bypass syslem 5,000 33,000 12 

and clupeids 

Pine (WI) Resident species 624 3.6 1990-91 265-ft long barrier net 10,000 25,000 56 2-3000 -- 200,000 (2-year EPRI co-funded study) (85-100% 

effective, less effective for flsb <1 OOmm) 

Milford (ME) Atlantic salmon 5630 6.4 1992-93 FtSb bypass syslem 5,000 45,000 9 1,100 26,200 

and clupeids 

Ellswortb (ME) Atlantic salmon 8.9 1989 Fisb bypass system, witb a 1!)- (1) 98,000 -- 1 17,280 

and clupeids ft wide weir 

Leaburg (OR) Anadromous 2175 13.5 1982-83 Palenled V screen in power 200,000 1,440,000 1,480 12,500 300,000 70,000/yr (1993)(90-98.6% effective in protecting 

salmonids canal witb wedgewire screening (253,715)(2) (1,826, 750)(2) fry when screen debris buildup controlled) 

and diversion syslem plus $1,139,297 

for improvements 

over 10 years 

Little Falls Anadromous -- 13.6 1989-90 0.5-inch mesh screens/0.5-incb (1) 130,140 -- 6000 -- 261,250 (1992) (licensee estimates fewer tban 1% of 

(NY)(2) blueback drilled plale witb fisb bypass herring in area were entrained. Study results 

herring syslem subjective.) 

T.W. Sullivan Anadromous 23,810 16.6 1980 Eicher screen & guidance (1) 408.413 (1 of 13 -- 12,000 63,000 60,000/yr (bypass efficiency: 77-95%) 

(OR)(2) salmon ids (average system penstocks) 

sile flow) 

Full Elltralllinenr ar HYdropower Pro)eds Page J-61 

Description of Protective 

Design Costs I Construction I & Design I Annual O&M I Generation I Effectiveness Study Costs ($) 

Site (State) Measure Costs($) Costs/csf ($) Costs ($) Costs ($) 

Twin Falls Resident trout 710 24 1989-93 Inclined wedgewire scn:ens 27,820 996,720 1,443 5,000 -- 17,120 (system meets agency guidelines) 

(WA)(2) with air bacldlusb 

Lower Anadromous 48,950 810 1992-93 19 submerged traveling screens (1) 4,996,900 -- 274,800 -- 244,700 (1992) (total fisb guidance efficiency nmaed 

Monumental salmon ids (averaae and 18 vertical barrier scn:ens from 35% for subyearling chinook salmon to 74% 

(WA)(2) site flow) for steelbead) 

(1) Desian costs not separated from construction costs. 

(2) Source: Francfort et at. 1994; costs reported as 1993 dollars. 

(3) Includes licensing costs. 

(4) Escalated to 1992 costs using ENR cost index. 

FISh Entra11111U!nllll HYdropower ProJects Page J-6J 

the Leaburg Project, where a patented Vconfigured wedgewire screening and bypass 

system was installed in the power canal in 

1983. Approximate cost for the initial 

design and construction of this facility, 

escalated to 1992 dollars, was $2,080,465. 

Additional improvements to the system were 

made to conform to resource agency 

recommendations during the 10 years that 

this system has operated and total 

$1,139,297. Therefore, the total cost of the 

facility as it is presently operating is 

$3,219,762 ($1,480/cfs). 

The Leaburg Project dramatically 

illustrates that the initial design and 

construction costs for protective measures 

are frequently less than the total costs of 

making the device fully functional. 

Additional capital costs may be incurred as 

a result of agency-recommended 

effectiveness studies that provide a basis for 

evaluation of performance goals and 

subsequent system modifications. The most 

recent (1993) annual cost associated with 

evaluating effectiveness of the Leaburg 

system was $70,000. At the Sullivan 

Project annual -;tudy costs are estimated to 

be $60,000. The approximate average 

annual operation and maintenance costs 

($12,000 to $12,500) and lost generation 

costs ($63,000 to $300,000) also represent 

substantial costs associated with the 

protective measures at these projects. 

Exclusion of resident species was the 

goal of three protective systems for which 

costs were provided: Twin Falls, 

Yellowstone, and Pine. The estimated cost 

of installing a "fish-stop grate" at the 

Yellowstone Project and a 265-foot-long 

barrier net at the Pine Project was $7,500 

($114/ cfs) and $35,000 ($56/ cfs), 

respectively. The installation at the Pine 

Project is representative of the costs at a 

small project ideally suited to this 

Fish Entrainment at Hydropower Projects 

technology. Installations at more complex 

projects, such as Brule and White Rapids 

(see Table 3-13), can be considerably more 

costly and illustrate the site-specific nature 

of the cost to install protective measures. A 

major cost associated with barrier nets is 

often operation and maintenance. O&M 

costs were estimated at $2,000 to $3,000 per 

year at Pine including replacement net costs, 

but may be substantially higher at sites with 

substantial debris loading. 

Installation costs associated with the 

inclined wedgewire screens at Twin Falls 

were substantially higher than Yellowstone 

and Pine. The installation cost of 

$1,024,540 ($1,443/cfs) rivals that of other 

Pacific Northwest facilities designed to 

protect anadromous salmonids. The 

unusually high cost is largely influenced by 

underground construction required at this 

site. Although costs at this site could be 

considered unique, this case underscores the 

site-specific nature of protective measure 

costs. 

Most respondents provided 

information on the conceptual cost of 

constructing protective measures in the 

future, since the questionnaire was sent to 

applicants of projects scheduled to be 

relicensed by the end of 1993. In some 

cases, the installation of protective measures 

was agreed to by the applicants and 

construction scheduled for completion within 

2 or 3 years of license issuance (Table 3-

13). Costs associated with these projects 

may be more representative than other 

conceptual costs presented for projects at 

which the timing and/or need for the 

protective measure has not been clearly 

established. 

Page 3-65 
(this page intentionally left blank) 
Chalk Hill WI Resident Species 3,500 7.8 ?(1989) 

Fish Enrrainmenr at Hydropower Projects 

I inch trasbrack 2Q,()()()<2l 

4,300,000 

(+275,000 lost 

generation) 

1,313 

(includes lost 

generation during 

construction) 100,000 

Page 3-67 

Plant Capacity 

Hydrau 

lie Eleclrical Cosls(l) y-1 Site State Species of Concern (cfs) (MW) Expected 

WalterviUe OR Anadromous Salmonids >2,175 8.0 1995 

Species 5,188 8.0 ? 

(I) Wben implementation date is unknown, the y- dollar values estimated is presented in parenthesis 

(2) Design cosls bave already been incurred (between 1989 and 1993) 

(3) Cosls of lost generation for the term of the license 

(4) Conceptual cosrs obtained from entrainment study reporrs 

(5) Electrical Capacity of Hawks Nest and Glen Ferris developmenls is combined 

I 

I 

Desaiption of 

Protective Measure 

-

Battier Net (Simplified) 

Barrier with 

Support.~ (450 ft Long) 

Battier Net (325 ft long) with spillway separation 

wall 

I 

Construction + 

I 

Annual I Annual Lost Design I Con~ I Design O&M Generation I Effectiveness 

Cos Is Costslcfs Cos Is Cosls Study Cosls 

($) ($) ($) ($) ($) ($) 

20;()()()1'1 90,000 21 

1,370,000 264 

3,460,000 I 667 I 60,000 

FmfKiitra~~~~~~ent at HYdropower ProJects Page 3-69 

Because applicants/licensees generally 

only install up-front (i.e., without 

entrainment studies) protective measures for 

resident fish when they are inexpensive, 

"actual" costs may not be representative of 

typical sites. 

Table 3-13 presents conceptual costs 

for protective measures at 25 sites. All but 

one of the 17 northeast sites include fish 

bypass systems and a specified component 

of these systems is often an angled l-inch 

trashrack. It is likely that a l-inch trashrack 

is also a component at some of the sites 

where it is not specified. One-inch 

trashrack costs are also provided for five of 

the eight remaining sites outside of the 

northeast. The most expensive protective 

measures based on total conceptual cost are 

the 110-foot-long, 47-foot-deep traveling 

screen system at Hawks Nest ($11 ,000,000) 

and a 1, 120-foot-long, l-inch trashrack 

system proposed for Buzzard's Roost 

($10,764,587). The most expensive 

protective measures from a cost/cfs 

perspective are the Walterville V-configured 

wedgewire screen system ($3,434/cfs) and 

the 61-foot-long, 15-foot-deep traveling 

screen system at the east powerhouse of the 

Glen Ferris Project ($3,021/cfs). The least 

expensive protective measure based on total 

cost is a $32,000 l-inch trashrack overlay 

with a bypass system proposed for the 

Pierce Mills Project in Vermont. 

Actual costs to design and install 

protective measures for projects with a 

capacity of less than 1 MW ranged from 

$4,700 to $92,900 (Table 3-14) and 

conceptual costs ranged from $32,000 to 

$222,000 (Table 3-15). These costs are 

generally higher than the range of $416 to 

$122,060 for 12 projects reported in Sale et 

al. (1991). Protective measures reported by 

Sale include projects with angled trashracks 

Fish Entrainment at Hydropower Projects 

(with and without bypass systems), velocity 

limits, and wedgewire screening systems. 

Most projects for which actual and 

conceptual costs for protective measures 

were provided have a capacity of from 1 to 

less than 10 MW. Actual capital costs for 

protective measures for projects of this size 

ranged from $35,000 to $692,710 (Table 3-

14). Conceptual capital costs for protective 

measures ranged from $72,000 to 

$7,468,500 (Table 3-15). These costs are 

generally comparable to costs reported by 

Sale et al. (1991) for developments of the 

same capacity, which ranged from $0 

(reflecting a plant that modified its turbine 

sequencing to protect fish) to $2,374,268 

(reflecting a plant that uses angled 

trashracks and a velocity limit on intake 

screens to protect anadromous and resident 

juvenile fish). Estimated actual O&M costs 

associated with the facilities represented by 

the present study ranged from $1 , 100 to 

$20,000 (capacity range: 1 to < 10 MW) 

and conceptual O&M costs ranged from 

$8,000 to $94,748. Sale et al. (1991) 

reported O&M costs of $0 to $43, 169 for 

projects of similar capacity. 

Actual and conceptual capital costs 

for plants with a capacity of 10 to 50 MW 

ranged from $200,000 to $11,000,000 and 

are generally higher than the range for 

projects with the same capacity reported by 

Sale et al. (1991), $92,996 to $2,807,381. 

Reported costs for specific protective 

measures are variable (Table 3-16) and 

primarily associated with the costs of l-inch 

trashracks. In part, this may be due to 

differences in the size and configuration of 

the intakes at various projects. In addition, 

different orientation (and therefore size) of 

trashracks may be necessary to reduce 

effective intake velocities experienced by 

fish to minimize entrainment. Some of the 

Page 3-71 
TABLE3-14 

SUMMARY OF ACTUAL COSTS ASSOCIATED WITH 

INSTALLATION OF ENTRAINMENT PROTECTIVE MEASURES 

Capacity Category 

Cost Type <1MW I 1- <10 MW I 10- <50 MW I >50MW 

Capital Costs (Design and 

Construct) 

Total 

resident fish sites $4,700- 92,900 (4) $35,000 (1) 1,024,540(1) -- (0) 

anadromous fish sites -- (0) $38,000 - 692,710 (5) $130,140-3,219, 762(3) 4,996.900 (1) 

Cost/cfs 

resident fish sites $31-808 (4) $56 (1) $1,443 (1) -- (0) 

anadromous fish sites -- (0) $9 - 1385 (4) $1,480 (1) -- (0) 

Annual Operation and 

Maintenance Costs 

resident fish sites $240 - 3000 (2) $2,000- 3,000 (1) $5,000 (1) -- (0) 

anadromous fish sites -- (0) $1,100- 20,000 (2) $6,000 - 12,500 (3) $274,800 (1) 

Annual Lost Generation 

Costs 

resident fish sites $1944 (1) -- (0) -- (0) -- (0) 

anadromous fish sites -- (0) $17,280- 26,200 (2) $63,000 - 300,000 (2) -- (0) 

Effectiveness Evaluation ' 

Costs 

1 

Annual 

resident fish sites $1000 (1) -- (0) -- (0) -- (0) 

anadromous fish sites -- (0) -- (0) $60,000 - 70,000 (2) -- (0) 

Total 

resident fish sites $6,000 (1) T 

$200,000 (1) $17,120 (1) -- (0) 

anadromous fish sites -- (0) _r- (0) $261,250 (1) 244,700 (1) 

Note: Numbers in parenthesis represent number of sites included in the range. 

Page 3-72 Fish Entrainment at Hydropower Projects 
TABLE 3-15 

SUMMARY OF CONCEPTUAL COSTS ASSOCIATED WITH 

INSTALLATION OF ENTRAINMENT PROTECTIVE MEASURES 

Cost Type 

Capital Costs (Design and 

Construct) 

Total 

resident fish sites 

anadromous fish sites 

Cost/cfs 

resident fish sites 

anadromous fish sites 

Annual Operation and 

Maintenance Costs 

resident fish sites 

anadromous fish sites 

Annual Lost Generation 

Costs 

resident fish sites 

anadromous fish sites 

Effectiveness Evaluation 

Costs 

Annual 

resident fish sites 

anadromous fish sites 

Total 

resident fish sites 

anadromous fish sites 

<1 MW 

$222,000 (1) 

$32,500 - 69,500 (5) 

$653 (1) 

$74- 160 (5) 

$47,374 (1) 

-- (0) 

$3,049 (1) 

-- (0) 

-- (0) 

-- (0) 

-- (0) 

-- (0) 

l 

Capacity Category 

1- <10MW I 

$72,000- 4,595,000 (13) 

$200,000- 7,468,500 (5) 

$16- 1,313 (12) 

$42 - 3,434 (5) 

$8,000 - 94,748 (8) 

$10,000- 12,500 (3) 

$11,100- 38,500 (3)* 

-- (0) 

-- (0) 

-- (0) 

$70,000 - 100,000 (3) 

$200,000 (1) 

10- <50 MW 

$1,528,000-10,764,587 (6) 

$200,000 - 300,000 (2) 

$306 - 3,021 (5) 

$50- 53 (2) 

$180,000 (1) 

$10,000 (I) 

$142,000 (1) 

-- (0) 

-- (0) 

-- (0) 

-- (0) 

-- (0) 

* One additional respondent presented lost generation costs for the term of the license, which was $198,000. 

Note: Costs presented by respondents were either escalated to year when costs scheduled to occur or, if year of 

construction unknown, to the year when the estimate was made. Dollar values ranged from 1989 to 1995 

and, because costs are conceptual, no attempt was made to escalate these estimates. Numbers in parenthesis 

represent number of sites included in the range. 

Fish Entrainment at Hydropower Projects Page 3-73 
TABLE 3-16 

RANGE OF DESIGN AND CONSTRUCTION COSTS ASSOCIATED 

WITH SPECIFIC ENTRAINMENT PROTECTIVE :MEASURES 

Actual Cost Conceptual Cost 

Item Total I Cost/cfs Total I Cost/cfs 

One-inch Trashracks: 

Trashrack only $88,000 (1) $352 (1) $456,525- 10,764,587 (4) $104- 2,691 (4) 

Trashrack Overlay $130,140 (1) -- $32,000- 250,000 (4) $74- 142 (4) 

with Bypass System 

Trashrack with $4,700 - 58,000 (2) $31 - 34 (2) $37,000- 1,529,000 (8} $50- 653 (8} 

Bypass System 

Fish Bypass System $38,000 - 98,000 (3) $9- 12 (2) $200,000 - 342,000 (4} $42- 360 (4) 

(may incorporate 

one-inch trashracks) 

Angled trashrack, $692,710 (1) $1,385 (1) -- -- 0.5-in. inclined fish 

screen with bypass 

Fish Stop Grate $7,500 (1) $114 (1) -- --

Barrier Nets: 

Simplified $35,000 (1) $56 (1} $77,000- $110,000 (2) $21 -56 (2) 

With Supports -- -- $1,370,000 (1} $264 (1) 

With Spillway -- -- $3,460,000 (1) $667 (1) 

Separation Wall 

V -configured $3,219,762 (1) $1,480 (1) $7,468,500 (1) $3,434 (1) 

Wedgewire Screen 

with Bypass System 

Cylindrical Wedgewire $92,900 (1) $808 (1) -- -- Screen with Air 

Back flush 

Inclined Wedgewire $1,024,540 (1} $1,443 (1) -- -- Screen with Air 

Backflush 

Eicher Screen $408,413 (1) -- -- --

Traveling Screen $4,996,900 (1) -- $472,000- $11,000,000* $107 - 3,021 (4) 

(4) 

Electric Screens -- -- $72,000 (1) $16 (1) . Sound Deterrent -- -- $178,000 (1) $40 (1) 

System 

* Costs for four developments at two projects. 

Note: Numbers in parenthesis represent number of sites included in the range. Costs do not include lost generation 

during construction. 

Page 3-74 Fish Entrainment at Hydropower Projects 
least and most expensive protective 

measures use l-inch trashracks whether 

considered on a total cost or cost per cfs 

basis. Sale et al. (1991) also found little 

correlation between the cost and the specific 

protective measure employed. One project 

included in their database reported total 

capital costs of $3,238 for angled 

trashracks, velocity limit on intake screens, 

and fish bypass systems. In general, 

installing traveling screens seems to be the 

most expensive protective measure, with 

costs starting at approximately $0.5 million. 

Construction costs for specific 

protective measures can be accurately 

estimated given sufficient design information 

on the device and adequate knowledge of 

site conditions. Lost generation related to 

bypass flows and head loss caused by 

screening systems also can be estimated, but 

less predictable are the future costs of 

O&M, effectiveness studies, and subsequent 

modifications that may be needed in 

response to these studies. Costs may range 

from virtually nothing to costs that exceed 

the initial capital costs of the protective 

measure. This uncertainty should be 

reduced as much as possible before deciding 

to implement specific measures. Conducting 

economic analyses of preferred options and 

establishing the potential for additional 

modifications by ·continuous interactions 

with resource agencies will help reduce 

uncertainty. 

The questionnaire asked for 

information on the effectiveness of specific 

protective measures, but respondents 

provided very little information in this area. 

Section 4.2 presents information on 

effectiveness. 

Fish Entrainment at Hydropower Projects Page 3-75 
(this page intentionally left blank) 
4.0 DISCUSSION 

4.1 Extrapolation of 

Entrainment Data 

Our statistical trend analyses (see 

Section 3.2.5) do not reveal consistent 

patterns to use for extrapolating entrainment 

results from one site to another site. Much 

of the variability in entrainment results 

between sites, however, may be caused by 

differences and biases in the sampling 

methodology, rather than by meaningful 

differences between sites. If study design 

and sampling methods are standardized (see 

Section 4.5), some statistically significant 

relationships may be identified in future 

entrainment studies. 

Lack of consistent statistical 

significance does not necessarily indicate 

that it is inappropriate to use the results at 

one site to make decisions about protective 

measures at another site. Decisions on fish 

protection should be based on the level of 

impact, which cannot be determined from 

total entrainment values. Total entrainment 

values also do not account for the size and 

species composition of entrained fish. 

Entrainment studies at a number of 

sites within a watershed may be used to 

extrapolate to other sites, especially sites in 

the same watershed. (Table 3-1 shows how 

such an extrapolation might be 

implemented). Using the entrainment rate 

adjusted for the hydraulic capacity of the 

plant (fish/hour/kcfs) probably is the most 

reasonable predictive value for 

extrapolation. For our analysis, we used the 

hydraulic capacity of the facility. When 

extrapolating results from one site to 

another, however, the best method is to use 

actual flow through the plant. 

Fish Entrainment at Hydropower Projects 

When more than one entrainment 

study was conducted on a river, the mean 

entrainment rate is also presented. This 

mean value sometimes does not accurately 

represent the site-specific entrainment rate at 

one site. For example, on the Au Sable 

River the entrainment rate at Five Channels 

is twice that of the mean value. On the 

Muskegon River, the entrainment rate at 

Hardy is one fifth of the mean value. Sitespecific characteristics may account for 

these differences; e.g., the Five Channels 

impoundment is the shortest and narrowest 

of the six sites studied on the Au Sable 

River, and Hardy is the only site of the 

three studied on the Muskegon River with 

an intake tower that draws water from the 

surface, the bottom, or both. Accounting 

for such characteristics may reduce the 

variability of entrainment rates between sites 

and help to identify appropriate sites for 

extrapolation. 

A decision to extrapolate entrainment 

data from one site to another should account 

for the relative value of the potential lost 

fishery. Because most entrained fish are the 

result of pulsed movements of young 

individuals, the actual loss to the fishery 

resource could be more similar among 

projects within the same basin than total 

entrainment rates would indicate. 

Applying the mean entrainment rate 

to other sites in the same watershed may 

have some predictive value. The mean 

entrainment rate at Brule, located 2 miles 

upstream of the confluence of the Brule 

River with the Menominee River, was 3.5 

fish/hour/kcfs, which is similar to the mean 

value of 2.6 fish/hour/kcfs for two sites on 

the Menominee River. Because of the small 

number of values available for comparison 

in this case, however, this similarity may 

not be representative. 

Page 4-1 
A review of the entrainment rates in 

Table 3-1 clearly indicates that it may not be 

appropriate to extrapolate entrainment 

results when entrainment at one site is 

heavily dominated by clupeids and the other 

sites are not (e.g., the Buzzard's Roost site 

[entrainment rate: 623.0 fish/hour/kcfs] 

compared to the other Broad River 

watershed sites [entrainment rate: 4.1-10.4 

fish/hour/kcfs]). It may be possible to 

extrapolate between sites if both are 

dominated by clupeids. Prior knowledge of 

the potentially affected fisheries resource is 

necessary before considering extrapolation. 

Assessment of varied monthly 

entrainment rates for representative species, 

without accounting for project proximity 

(Section 3.2.6), indicates that it may be 

difficult to establish an action "trigger" (that 

rate at which protective measures at an 

unsampled site may be required) of 

entrainment rate for specific species. 

Monthly entrainment rates were extremely 

variable between sites, although there were 

some seasonal trends (e.g., low entrainment 

rates of smallmouth bass, walleye, and white 

sucker during the winter). Variable 

monthly entrainment rates between sites may 

not substantially affect the relative annual 

entrainment rate if the variable rates are 

caused by a seasonal shift in entrainment. 

In other cases, however, the monthly 

variability relative to other sites in the same 

basin is much greater than can reasonably be 

attributed to seasonal shifts (e.g., 

smallmouth bass at Wisconsin River 

Division; walleye at Foote and Hardy; and 

black crappie at Croton, White Rapids, 

Rothschild, and Ninety-nine Islands). At 

some sites, the entrainment rate for some 

species is substantially different than for 

others during specific times of the year. 

Such major variations translate into intersite 

differences in annual entrainment rates for 

Page 4-2 

certain species that may not be attributable 

to an identifiable cause. 

When considering extrapolation of 

entrainment results at sampled sites to 

unsampled sites there is a risk that a 

licensee/applicant could be required to 

install protective measures that are not really 

necessary, or that protective measures will 

not be recommended at sites where their 

installation is justified. This risk must be 

recognized when evaluating the 

appropriateness of extrapolation. The risks 

associated with extrapolation can, however, 

be minimized if entrainment studies at 

sampled sites are carefully designed and 

implemented using standardized procedures 

and/or the resource loss is of less value than 

the cost of protective measures (see Sections 

4.4 and 4.5). Risks can be further reduced 

by confining extrapolation to sites within the 

same basin and with similar site 

characteristics (e.g., presence of clupeids, 

presence of upstream stocking programs, or 

similar site configuration). 

4.2 Cost and Effectiveness of 

Protective Measures 

Responses to our questionnaire 

provided little information on the 

effectiveness of protective measures, 

because few applicants had installed and 

evaluated measures. Many respondents 

indicated that protective measures were 

scheduled to be installed within 2 to 3 years 

after issuance of a new license. It will 

probably take an additional 1 to 2 years 

before the results of evaluation studies are 

available for most of these sites. 

Because of the limited information 

gathered from the questionnaire, we 

supplemented this section with other sources 

available to SWEC from past and ongoing 

fish protection studies conducted for the 

Fish Entrainment at Hydropower Projects 
Electric Power Research Institute (EPRI), 

DOE (Fra.ncfort et al., 1994), and individual 

licensees/applicants. 

The following sections summarize 

available information on the cost and 

effectiveness of commonly prescribed 

protective measures and of other 

technologies that are currently under 

development. 

4.2.1 Low-Velocity Fish Screens 

Low-velocity fish screens provide a 

sufficient amount of screen area to lower 

velocity approaching the screen and 

minimize potential impingement and injury. 

Most current designs set screens at an angle 

to the flow to direct fish towards 

downstream bypasses. Types of screening 

facilities most commonly considered include 

rotary drum screens; vertical traveling 

screens; and stationary screens equipped 

with debris removal apparatus such as 

traveling brushes, high-pressure backwash, 

or air-burst systems. 

Low-velocity screening systems are 

the protective measure most readily accepted 

by fisheries agencies in the Pacific 

Northwest. Agencies there prefer to use 

well-proven technologies to protect valuable 

runs of salmon and/or steelhead trout. 

Many state agencies, as well as the regional 

office of the National Marine Fisheries 

Service, have developed design criteria for 

such screening and bypass facilities. 

Facilities usually are constructed to protect 

newly emergent fry with an approach 

velocity (pe1pendicular to the screen face) of 

0.4 feet per second (fps). California 

recommends a maximum approach velocity 

of 0.33 fps. 

Low-velocity screening systems are 

a relatively well-proven protective measure 

Fish Entrainment at Hydropower Projects 

for juvenile salmonids. Evaluation of 10 

angled drum screen facilities in the Yakima 

River Basin (Hosey & Associates, 1990; 

Neitzel et al., 1990) showed that the 

proportion of bypassed fish with substantial 

scale loss or mortality usually is less than 1 

or 2 percent. Potential losses from 

predation and/or escapement past the screen 

seals have not been as thoroughly evaluated. 

Predatory fish and/or birds may take some 

fish within the low-velocity area of the 

facility itself, and predation is a common 

problem at outfalls where bypassed fish are 

returned to the river (outfall predation is a 

potential problem for any bypass system 

[Francfort et al., 1994]). Poorly installed or 

worn screen seals also can allow fish to 

escape past the screens, particularly at 

rotary or vertical traveling screens. 

Evaluations to date have rarely demonstrated 

a recovery rate exceeding 90 percent of the 

fish released upstream of the facility. This 

may be due to nonmigratory behavior 

(residualism) of some test fish or to losses 

from predation and/or escapement past the 

screens. 

Capital costs of constructing lowvelocity screening systems generally range 

from $1,300 to $10,000 per cfs of plant 

capacity. This cost range is based on sites 

where the screening facility is located in a 

shallow power or irrigation canal and on 

sites in the Pacific Northwest where the 

primary objective is protection of juvenile 

and smolts of salmonid species. 

Construction costs probably would exceed 

this range in deep forebay applications due 

to the extensive civil works needed to 

support a large screening facility. Most 

designs cannot prevent damage from winter 

ice or severe debris loading, and 

maintenance costs can be substantial. 

Another drawback in constructing such a 

facility is that it usually requires a large area 

to be fenced off for public safety and to 

Page 4-3 
prevent vandalism, which affects public 

access and aesthetics. 

4.2.2 High-Velocity Fish Screens 

Several newer screen designs may 

provide equal or better protection at 

approach velocities well in excess of those at 

low-velocity screening systems. Designs 

include the fixed panel, "vee" design 

employed at the Leaburg Project in Oregon; 

the "Eicher Screen" designed for application 

in penstocks; and the "Modular Inclined 

Screen" under development by EPRI. All 

three designs use wedgewire or profile bar 

screen material, which provides a very 

smooth surface that minimizes injury or 

impingement. 

Leaburg "Vee" Screen 

The "vee" screen at the Leaburg 

Project was installed in 1983, and has 

subsequently been patented by the Eugene 

Water and Electric Board (EWEB). It has 

six vertical screen panels in a "triple-vee" 

configuration. The facility was designed 

with an average approach velocity 

(perpendicular to the screen) of 0. 75 fps, 

and most evaluation testing has been 

conducted at approach velocities between 

0. 6 and 0. 75 fps. After initial testing, a 

pressure backwash system for debris 

removal and adjustable baffles behind the 

screen were added to provide a more 

uniform flow distribution along the length of 

the screen panels. EWEB reports that, in 

recent tests, small salmon fry (35 to 40 mm) 

are protected from entrainment at a 98.6 

percent rate at full canal flows when debris 

build-up on the screen is controlled (EWEB, 

1993). Construction costs reported for the 

Leaburg screen, including modifications, are 

$1,480 per cfs (escalated to 1992 dollars). 

EWEB is designing a similar facility for 

their Walterville Project, with an estimated 

Page 4-4 

construction cost of $3,434 per cfs. These 

costs fall within the lower end of the range 

usually reported for low-velocity screening 

systems. 

Eicher Screen 

The Eicher Screen, designed for use 

in penstocks, provides effective ftsh 

diversion at approach velocities 

(perpendicular to the screen) in excess of 2 

fps. The design has an inclined wedgewire 

screen mounted on a pivot shaft, which 

allows the screen to be tilted to flush debris. 

The design was initially developed for 

application at the Portland General Electric's 

Sullivan Hydroelectric Project on the 

Willamette River in Oregon, and it was 

patented by George Eicher. Despite poor 

hydraulic conditions imposed by the layout 

of the intake structure, evaluations in 1981 

with salmon and steelhead smolts indicated 

that the screen has a diversion efficiency of 

at least 94.9 percent to 99.6 percent (Clark, 

1981). Recent studies conducted with an 

improved sampling facility also 

demonstrated low injury rates, generally less 

than 3 percent even without accounting for 

pre-existing injuries (Clark and Cramer, 

1993). 

To fully evaluate the potential 

effectiveness of this screen design, EPRI 

funded evaluation studies during 1990 and 

1991 of an Eicher Screen installed by James 

River IT, Inc. in a 9-foot-diameter penstock 

at the Elwha Hydroelectric Project in 

Washington. The screen was installed in a 

straight penstock section, providing more 

uniform hydraulic conditions than existed in 

the irregularly shaped intake of the Sullivan 

Project. 

Extensive evaluation demonstrated 

that the Eicher Screen at Elwha was highly 

effective in diverting steelhead trout, coho 

Fish Entrainment at Hydropower Projects 
and chinook salmon smolts with minimal 

losses. Diversion efficiency exceeded 99 

percent overall for all three species of 

smolts evaluated (EPRI, 1992a) at penstock 

velocities ranging from 4 to 7.8 fps. These 

test velocities equate to an average velocity 

perpendicular to the screen of 1.35 to 2.67 

fps. The average passage survival (fish 

diverted live and surviving 96 hours 

following passage) ranged from 98.8 percent 

to 99.4 percent for the three species of 

smolts. A limited series of tests conducted 

with steelhead and coho fry indicated that 

passage survival exceeded 95 percent at 

penstock velocities of less than 7 fps. 

Debris tests conducted with all three species 

indicated that the potential for fish injury 

and impingement increased at debris 

loadings causing over 0.2 feet of head loss. 

The screen was rapidly cleaned of debris, 

however, when it was tilted to the flushing 

position. 

As a result of Elwha's success, B.C. 

Hydro installed Eicher Screens during 1992 

in two penstocks at the Puntledge Hydro 

Project in British Columbia. Preliminary 

results indicate that the screens at Puntledge 

are achieving over 99 percent diversion and 

survival (Smith, 1993). Total costs for 

construction of the Puntledge screens 

amounted to $4 million (U.S.) to screen 

1,000 cfs, or $4,000 per cfs (about half of 

the cost that was estimated for installing an 

alternative low-velocity screening system). 

A cost estimate prepared in 1990 for 

screening the entire 2, 000 cfs capacity at 

Elwha showed a cost of $1,500 per cfs, 

compared to an estimate of $3,557 per cfs 

for a low-velocity screening system. Data 

from these two sites indicate that Eicher 

Screens usually can be constructed at about 

half the cost of the low-velocity screening 

systems typically prescribed in the Pacific 

Northwest. 

Fish Entrainment at Hydropower Projects 

Modular Inclined Screen 

EPRI currently is conducting a 

program at the Alden Research Laboratory 

(ARL) in Holden, Massachusetts, to develop 

and evaluate a modular inclined screen 

(MIS). The goal of the program is to 

develop a standardized, proven design that 

can be applied at nearly any type of water 

intake. The design has an inclined 

wedgewire screen mounted on a pivot shaft, 

contained in a rectangular module 

incorporating design features that provide a 

more uniform flow distribution than can be 

achieved in a penstock application. A fullsized module would contain a screen about 

30 feet long by 10 feet wide inclined at an 

angle of 15 degrees, and would be capable 

of screening up to 1,000 cfs at a module 

velocity of 10 feet per second. Transition 

walls along the downstream third of the 

screen would taper to a 2-foot by 2-foot 

bypass entrance. 

The MIS design was refmed during 

hydraulic model studies conducted at ARL 

in a 1:6.6 scale model, and biological 

evaluation tests were conducted in a 1:3.3 

scale model. Diversion efficiency, injury, 

and 3-day survival was evaluated for 10 

species of fish, with the average size of test 

species ranging from 1. 9 inches to 6. 76 

inches. Module velocities of 2 to 10 fps 

were evaluated, corresponding to an average 

velocity perpendicular to the screen of 0.8 

to 4.0 fps. 

Winchell et al. (1993) and Taft et al. 

(1993) summarize results of the MIS 

biological testing program. Detailed results 

were published in an EPRI report (EPRI, 

1994b). Passage survival (percent diverted 

live and surviving for 3 days after passage) 

exceeded 99 percent overall for juvenile 

channel catfish, brown trout, coho salmon, 

chinook salmon and Atlantic salmon smolts. 

Page 4-5 
Passage survival for most other species 

approached or exceeded 99 percent at 

velocities of up to 4 fps (bluegill and golden 

shiner juveniles) or 6 fps (walleye juveniles, 

rainbow trout fry and juveniles). The only 

species group with an overall passage 

survival of less than 95 percent was alosid 

juveniles (mixed blueback herring and 

American shad). Poor results for this 

species were attributed to stress caused by 

collection, transport, and testing. 

Similar to the fmdings of the Eicher 

Screen study, test results indicated that 

debris accumulations causing over 0.2 feet 

of head loss generally resulted in an increase 

in injury and impingement of small fish (no 

impingement was observed for the relatively 

large Atlantic salmon smolts at a head loss 

of up to 0.5 feet). Again, most debris types 

were readily flushed by tilting the screen for 

a brief period, although tests conducted with 

pine needles found that some of them 

remained on the screen after flushing. 

A recent comparison of six screening 

alternatives under consideration for a 3,000 

cfs irrigation diversion in California 

provides cost information on construction of 

an MIS screening facility. Cost estimates 

prepared by an independent engineering firm 

came to $3,286 per cfs for the MIS 

alternative, while the five, low-velocity 

screening alternatives ranged between 

$6,947 and $12,394 per cfs. 

4.2.3 Fish Bypasses at Existing 

Trash racks 

Many downstream passage facilities 

prescribed in the New England area consist 

of bypasses installed adjacent to existing 

trashracks. Typically the bypasses are 

installed to provide an alternative to turbine 

passage for outmigrating Atlantic salmon 

smolts, juvenile American shad, and juvenile 

Page 4-6 

river herring (blueback herring and 

alewives). Because many small fish avoid 

passing through trashracks (Anderson, 1988, 

as cited in Kynard, 1993), fish migrating 

downstream may fmd and use an 

appropriately located bypass route. 

Surface bypasses are being installed 

at trashracks to facilitate downstream 

passage at sites in the northeast, where most 

salmon and clupeid stocks are in a gradual 

rebuilding phase. Access to upstream 

habitat is progressively increasing as new 

upstream passage facilities are constructed. 

Because of the currently small run size of 

Atlantic salmon (the most highly valued 

stock in the northeast region) it is difficult to 

justify the cost of installing state-of-the-art 

screening facilities such as those prescribed 

in the Pacific Northwest. Furthermore, for 

the low-head projects typical on the east 

coast, costs of fish screening systems, which 

are generally proportional to the volume of 

flow that must be screened, are relatively 

high. 

Appropriately located bypasses may 

offer an acceptable long-term method of 

downstream passage at sites where fish 

behavior under existing site conditions is 

conducive to achieving high bypass rates. 

At some sites, monitoring studies may yield 

information to enable simple modifications 

for improving bypass efficiency. At other 

sites, however, more extensive protective 

measures probably will be recommended to 

provide an acceptable level of protection. 

Public Service of New Hampshire 

(PSNH) studies to develop downstream 

passage facilities for Atlantic salmon at five 

dams on the Pemigewasset and Merrimack 

rivers are a good example of an effective 

approach in the northeast. During 1989 and 

1990, PSNH monitored the migration of 

radio-tagged salmon smolts via all potential 

Fish Entrainment at Hydropower Projects 
passage routes at each dam. Results 

indicated that fewer than 5 percent of the 

smolts used bypasses installed adjacent to 

the project intakes (PSNH, 1992). The 

average proportion of fish passing via all 

non-turbine routes (including spillways and 

waste gates) ranged from 54.9 percent to 

95.5 percent for the four sites where 

sufficient data were collected. 

Follow-up studies conducted in 1991 

and 1992 largely focused on improving 

passage at one of the dams (Ayers Island), 

where there was a substantial delay in 

outmigration during non-spill conditions. 

The 1992 studies found that surface spill 

provided by dropping a single flashboard 

was used by 30 of 46 smolts recorded 

passing the project (NUSCo, 1993). Studies 

to develop effective downstream passage 

facilities at all five dams are ongoing. 

Capital costs reported for 

constructing fish bypass systems (see 

Sections 3.4.2 through 3.4.6) ranged from 

$9 to $12 per cfs for constructed sites (two 

sites), and conceptual costs of $42 to $360 

per cfs were reported for four other sites 

(see Table 3-16). Lost generation due to 

providing bypass flows probably is a greater 

overall cost than actual construction of the 

bypasses. Even considering lost generation, 

simple bypasses are considerably less costly 

than state-of-the-art screening facilities. 

Installation of bypasses, however, does not 

preclude the possibility that additional 

measures may be recommended in the 

future. 

4.2.4 Close-Spaced and Angled Bar 

Racks 

Since the early 1980's, angled bar 

racks combined with controlled spills at a 

bypass facility have been one of the most 

commonly installed fish protection systems 

Fish Entrainment at Hydropower Projects 

for hydropower projects, particularly in the 

northeast. Most angled bar rack facilities 

consist of a single bank of racks in front of 

the turbine intake at an angle of about 45 

degrees to the flow. Although design varies 

from site to site, most use vertical bars 

oriented perpendicular to the plane of the 

rack with a l-inch spacing and a bypass 

located at the downstream end of the rack. 

Generally, resource agencies specify a 

maximum approach velocity (perpendicular 

to the racks) of 2 fps and a bypass flow 

equivalent to 2 percent of the plant flow or 

20 cfs (whichever is greater). 

Most angled bar rack facilities, 

which have been installed at small projects 

(capacity less than 1,000 cfs), have not been 

evaluated. One performance evaluation was 

at the Wadhams Hydroelectric Project, a 

small (150 cfs capacity) project located on 

the Bouquet River in Wadhams, New York. 

The study compared passage routes of radiotagged Atlantic salmon smolts passing the 

project with l-inch spaced bar racks 

installed at 90 degrees and 36 degrees to the 

intake flow. Although sample sizes were 

small, the study concluded that the angled 

racks substantially reduced the entrainment 

rate of salmon smolts into the project intake 

(Nettles and Gloss, 1987). None of the 30 

migrants passed through the penstock when 

the angled trashracks were in place ( 18 

passed via the bypass and 12 passed via the 

spillway), while three out of six fish passed 

via the penstock when the racks were 

oriented perpendicular to the intake. 

One respondent to the entrainment 

protection questionnaire indicated that l-inch 

spaced trashracks were 100 percent effective 

in eliminating entrainment of landlocked 

Atlantic salmon at the Millinocket Pumping 

Station on the Penobscot River in Maine. 

Although trashracks did not eliminate 

Page 4-7 
entrainment of smelt, this was not an 

objective of the installation. 

Although little additional data 

currently are available to substantiate the 

effectiveness of l-inch angled bar racks, it 

seems likely that they would be effective in 

reducing the entrainment rate of larger fish 

capable of a sustained swimming speed of 2 

fps or more simply because large fish would 

be physically excluded. In addition, smaller 

fish may avoid the turbulence created by the 

racks. This is the biological principal 

involved in the use of louvers (see Section 

4.2.5), which can be effective in guiding 

fish that could physically pass between the 

louver slats. Similar to louvers, the 

diversion efficiency of angled bar racks 

probably drops off rapidly for very small 

fish, and some weak-swimming species may 

be impinged if the bar racks are not 

designed properly. Passage of very small 

fish through bar racks may not be a major 

concern, however, because smaller fish have 

low rates of turbine mortality at most sites 

where this was studied. 

Use of trashrack overlays for 

reducing the entrainment rate of blueback 

herring was evaluated during 1992 at the 

Little Falls Project (RMC, 1993). Overlays, 

which were constructed of perforated steel 

plate with 0.5-incli holes, with an overall 

porosity of 60 percent, covered the top 20 

feet (about 60 percent) of the trashracks. 

During testing, a range of spill flows were 

provided through an ice sluice located 

adjacent to the trashracks. Results indicated 

that the trashrack overlays were not effective 

in preventing entrainment of herring into the 

powerhouse. Although some increase in 

sluice passage was noted with increases in 

sluice discharge, even at the higher sluice 

flows more fish usually passed through the 

powerhouse. 

Page 4-8 

Capital costs reported for 

construction of close-spaced bar racks with 

a fish bypass system (see Tables 3-14 

through 3-16) was $31 to $34 per cfs for the 

two constructed sites, and conceptual costs 

ranged from $50 to $653 per cfs for another 

eight sites. Although angled bar rack 

installation has a fairly sound theoretical 

basis, currently there is a limited amount of 

quantitative data on its effectiveness. 

4.2.5 Louvers 

A louver system consists of an array 

of evenly spaced, vertical slats (normally 

spaced with clear openings of 1 to 12 

inches) aligned across a channel at a 

specified angle and leading to a bypass. 

Because fish tend to orient themselves facing 

into a current, even if they are moving with 

it, they cannot see obstructions or barriers 

downstream. Fish must rely mainly on their 

other senses to guide them around obstacles, 

and louvers take advantage of this behavior. 

As fish approach louvers, they sense the 

turbulence created by the system and move 

laterally away from it. They are carried 

downstream where their lateral movement 

and the current eventually direct them into a 

bypass. 

EPRI (1986) reports results of testing 

performed in laboratory studies and at large 

louver installations in Washington, Oregon, 

and California. Most studies showed good 

guidance (greater than 85 percent) for fish 

greater than 1.2 to 2.4 inches long, but 

generally much lower performance for fry. 

The relationship between fish length and 

guidance efficiency was demonstrated· in the 

results of testing (published in 1974) at the 

John Skinner Fish Facility located at the 

intake for the California Aqueduct. The 

guidance efficiency at this facility decreased 

rapidly for striped bass less than 1.2 inches 

and for white catfish less than 3. 6 inches 

Fish Entrainment at Hydropower Projects 
(EPRI, 1986). More recent tests conducted 

during the 1980's at a louver facility located 

at the Red Bluff Diversion dam on the 

Sacramento River (Vogel et al., 1990) 

showed a similar decrease in guidance of 

chinook salmon less than 2 inches long. 

Due to low guidance of chinook fry and 

predation at the existing bypass outfall, this 

louver facility was replaced with an angled 

drum screen facility in 1990. 

Recently, the Northeast Utilities 

Service Company (NUS Co) began a major 

research effort to evaluate louvers for 

diverting juvenile and adult clupeids and 

Atlantic salmon smolts at the Holyoke Canal 

on the Connecticut River in Holyoke, 

Massachusetts. The canal is about 145 feet 

wide with a maximum flow capacity of 

7,000 cfs. A 522-foot-long floating louver 

array was installed at an angle of about 15 

degrees to the flow, with 2.5-inch wide 

louvers installed perpendicular to the flow at 

a 3-inch spacing. Effectiveness of the 

floating louver array was evaluated during 

1990 by monitoring the migration routes of 

radio-tagged fish to determine whether they 

were guided along the length of the array to 

a 15-foot-wide gap at the end of the array. 

Louver depths of 4 to 8 feet were evaluated 

during the initial test program. 

Testing during 1990 indicated that 

the floating louver array guided an average 

of 87 percent of Atlantic salmon smolts 

(NUSCo, 1990). The effectiveness of the 

louvers declined slightly when the louver 

panels were raised from their design depth 

of 8 feet, although the difference was not 

statistically significant. Tests conducted 

with the louver panels removed (support 

frame left in place) showed a guidance 

efficiency of 75 percent, indicating that a 

wider slat spacing could be effective in 

guiding Atlantic salmon smolts. Tests 

conducted with post-spawning adult 

Fish Entrainment at Hydropower Projects 

American shad also indicated successful 

guidance, although the results were 

inconclusive because shad tended to move 

back upstream and mill in the vicinity of the 

louver array (Harza and RMC, 1990). 

Based on the success of the floating 

louver array, a permanent bypass and fish 

sampling facility was installed in 1992, and 

two modifications to the louver array were 

tested. In spring 1992, the louver array 

consisted of 402 feet of floating louvers and 

40 feet of full-depth (20 feet) louvers 

adjacent to the bypass entrance. Studies 

conducted using hatchery Atlantic salmon 

smolts found that the guidance efficiency of 

the louver array was 91.3 percent with a 3-

inch spacing between slats and 79.7 percent 

with a 12-inch spacing (Harza and RMC, 

1992). 

In fall 1992, an evaluation of 

juvenile clupeids (American shad and 

blueback herring) was performed at Holyoke 

at various canal flows with a non-floating 

louver facility. The facility consisted of 400 

feet of 9-foot-deep, 2-inch spaced louvers 

plus 40 feet of full depth (20 feet) louvers 

adjacent to the bypass. The study found that 

76 percent of marked and recaptured test 

fish were guided, and 86 percent of 

naturally migrating fish were guided into the 

bypass (Harza and RMC, 1993). 

The non-floating facility described 

above was evaluated with hatchery and wild 

Atlantic salmon smolts at various canal 

flows. The report is currently in 

preparation, but data indicate that the overall 

effectiveness was between 85 percent and 90 

percent. 

Total project cost for construction 

and evaluation of the various louver 

configurations tested at Holyoke was 

approximately $6 million, about half of 

Page 4-9 
which was incurred during evaluation 

studies. With a canal capacity of 7,000 cfs, 

this is a cost of about $857 per cfs for the 

total program and $428 per cfs for 

installation of the louvers alone. 

4.2.6 Barrier Nets 

Barrier nets are potentially a lower 

cost method of reducing fish entrainment 

rates. About half of the installations, 

however, have been ineffective and/or have 

needed extensive maintenance efforts due to 

biofouling, debris loading, excessive 

velocities, and/or wave action. Barrier nets 

prevent or reduce entrainment of resident 

species, but do not usually incorporate any 

type of bypass for movement downstream 

from the dam. 

In 1983 and 1984, evaluation of a 

barrier net installed at the J. R. Whiting 

plant in Michigan indicated that the net 

reduced impingement of gizzard shad and 

yellow perch on the 3/8-inch traveling 

screens (located behind the barrier net) by 

89 to 95 percent and 94 to 97 percent, 

respectively, from levels reported in 1978 

and 1979 before barrier net installation 

(CPC, 1985). Monitoring studies conducted 

in 1984 indicated that overall impingement 

rates (a measure of how many fish passed 

through or around the net at this steam 

electric plant) decreased by 97 to 99 percent 

compared to the same years. 

An extensive 2-year evaluation was 

also performed of a barrier net installed 

during the ice-free season at the Pine 

Hydroelectric Project in Wisconsin. Fullflow netting of the power canal indicated 

that the total entrainment rate was reduced 

by about 70 percent (SWEC, 1991; EPRI, 

1992b). Many fish were captured in the 

first month after the net was deployed, 

suggesting that most of these fish resided 

Page 4-10 

downstream of the net at the time it was 

deployed. larger fish (greater than 4 inches 

long) were excluded based on results of 

mark-recapture studies, which indicated a 92 

percent reduction in the entrainment rate for 

this size range. Effectiveness of the barrier 

net might have been greater if the net 

extended to the water surface, but due to 

debris loading concerns, the net was 

deployed 12 to 18 inches below the surface. 

The net is scheduled· to be redeployed in 

1994 or 1995. 

A large barrier net (2. 5 miles long) 

has been used at the Ludington Pumped 

Storage plant on Lake Michigan since 1989. 

Evaluation studies conducted during 1989 to 

1990 indicated 30 to 3 7 percent overall 

effectiveness; however, the effectiveness 

improved to 77 to 84 percent in 1991 to 

1992 (CPC and Detroit Edison Company, 

1992). 

Other installations where barrier nets 

have been less effective include the Quad 

Cities Station on the Mississippi River and 

the Eastlake Generating Station on Lake 

Erie. Debris loading and biofouling caused 

extensive problems at the Quad Cities 

barrier net (LMS, 1986). Wave action, 

debris loading, and shifting substrate caused 

similar problems at the Eastlake Generating 

Station (Environmental Resource Associates, 

Inc., 1984, cited in LMS, 1986). 

Cost information on barrier nets is 

only available for Pine, where design, 

construction, and installation of the net cost 

approximately $35,000, or $56 per cfs of 

plant capacity. Operation and maintenance 

costs are approximately $2,000 to 3,000 per 

year (including periodic net replacement); 

these costs could be substantially higher at 

sites with greater debris loading. 

Fish Entrainment at Hydropower Projects 
4.2. 7 Behavioral Barriers 

There has been extensive research on 

the use of behavioral devices including 

sound, lights, and electrical fields for 

protecting fish at water intakes. EPRI 

(1986) summarizes much of the earlier 

work, and detailed information on more 

recent studies is presented in an update to 

the 1986 report (EPRI, 1994a). 

Results obtained with most 

behavioral devices have been highly 

variable. All known behavioral guidance 

systems are experimental installations, 

although some systems currently being 

evaluated probably will be incorporated into 

permanent installations. The most 

promising results, although highly speciesspecific, have been obtained with strobe 

lights and transducer sound systems. In the 

following section we summarize several test 

programs that have demonstrated effective 

fish guidance with behavioral devices. 

Strobe lights show good promise for 

diverting outmigrating juvenile American 

shad and possibly Atlantic salmon smolts. 

Tests conducted at the York Haven 

Hydroelectric Project on the Susquehanna 

River in Pennsylvania showed that strobe 

lights are highly effective for repelling shad 

into an ice sluiceway used as a fish bypass. 

Outmigrating shad at this site tend to avoid 

passing through the trashracks at the turbine 

intakes, and large numbers of fish 

accumulate at the end of the intake canal 

during low-spill years. Test results from 

1991 indicated that an average of 1,712 shad 

passed through the sluiceway during each 2-

minute strobe test, while the average 

sluiceway passage during control periods 

with the same sluiceway flow was only 38 

fish (EPRI, 1992c). Metropolitan Edison is 

Fish Entrainment at Hydropower Projects 

continuing studies to develop a permanent 

bypass system using strobe lights at this site. 

Studies conducted at Weldon dam on 

the Penobscot River indicate that strobe 

lights may divert Atlantic salmon smolts. In 

1988, strobe lights were installed at the 

intake to one unit, and the passage rate of 

smolts through a fish bypass pipe at the unit 

were evaluated with and without the strobe 

lights in operation. The results showed that 

78 percent fewer smolts entered the bypass 

pipe when the strobe lights were operating 

(GPC, 1988). As a result, strobe lights 

have been incorporated into a new fish 

bypass system installed during 1992. The 

bypass system incorporates l-inch spaced 

bar racks at all four units, bypass facilities 

at the two near-shore units, and strobe lights 

to repel fish from the intakes of the other 

two units. Evaluation studies are ongoing. 

Two patented sound projection 

systems have recently been evaluated. 

Developers of both systems customize the 

sound level and frequency to optimize the 

response of the target species. The sound 

system developed by the American Electric 

Power Corp. yielded the best results at the 

Buchanan Hydroelectric Project on the St. 

Joseph River in Michigan. The sound 

system was deployed in the project's 

headrace, and its effectiveness was 

monitored by comparing the catch rates in 

nets deployed immediately downstream of 

the sound projectors (total passage rates into 

the headrace were not evaluated). Although 

few fish were caught in the nets, test results 

indicated that 94 percent fewer steelhead 

smolts and 81 percent fewer chinook smolts 

were caught in the nets when the sound 

system was operating (Loeffelman et al. , 

1991; Klinect et al., 1992). 

Page 4-11 
Sonalysts Incorporated developed a 

second, patented sound system. Testing 

conducted at the James A. Fitzpatrick 

Nuclear Plant on Lake Ontario showed that 

at maximum circulating pump operation, a 

full-scale sound system resulted in an 87 

percent decrease in alewife impingement 

(Ross et al., in press). The Sonalysts 

system also showed potential for diverting 

juvenile American shad. Testing conducted 

during 1992 at the Vernon Hydroelectric 

Project on the Connecticut River 

demonstrated that outmigrating shad showed 

a strong avoidance response to the sound 

system (RMC, 1993). 

Because there are few data on 

operation of full-scale behavioral guidance 

systems, there is little cost information 

available. Based on the cost of the 

components involved, however, full-scale 

strobe light or sound systems probably could 

be deployed for between $100,000 and 

$1,000,000 for a 10,000 cfs capacity plant, 

or about $10 to $100 per cfs. Results to 

date indicate, however, that behavioral 

systems may not be effective for some target 

species, and that evaluation studies may be 

required to demonstrate effectiveness. 

4.3 Entrainment Rates Relative to 

Impoundment Populations 

Abundance of many species in 

impoundments relative to entrained species 

(see Section 3.3) probably can be attributed 

to habitat preferences and behavioral 

patterns. The position of the plant intake 

plays a major role in which species are most 

often entrained. For example, a relatively 

shallow impoundment with much aquatic 

vegetation is ideally suited to centrarchids. 

If the project intake is located in relatively 

deep water and away from spawning and 

nursery areas, however, entrainment rates of 

centrarchids would probably be low. 

Page 4-12 

Conversely, an impoundment as a whole 

may be relatively poor centrarchid habitat, 

but if the project intake is located near good 

spawning and nursery habitat, the number of 

entrained centrarchids could be relatively 

high, especially when the juveniles leave the 

nests in mid- to late summer or when the 

aquatic vegetation associated with nursery 

areas dies back in the fall (most entrained 

centrarchids are juveniles). Habitat mapping 

conducted at some of the Au Sable and 

Muskegon river projects (especially Five 

Channels) and the King Mill Project 

supports this explanation. 

There is not enough information 

available to support broad generalizations 

about the relationship of impoundment 

populations to entrainment rates. Most 

population estimates are conducted on adult 

resident sportfish, and most entrained fish 

are juveniles. If the population of a species 

in an impoundment is relatively high, 

however, such as the 19 walleye per acre (3-

to 26- inches long) at Crowley, the number 

of entrained juveniles of that species also is 

probably relatively high (Table 3-10). 

High densities of adults create 

situations where density-dependent 

mechanisms limit the number of juvenile 

fish that reach adulthood. Mechanisms 

include increased predation and migration 

from the impoundment. The degree of 

outmigration probably is influenced by how 

close the impoundment is to its carrying 

capacity and behavioral characteristics of the 

species. For example, juvenile walleye tend 

to be more pelagic than juvenile sunfish. 

Therefore, young walleye outmigration 

probably is more important than predation as 

a density controlling factor for this species. 

An intake in open water (removed from 

shoreline habitat) would probably show high 

walleye entrainment rates when the density 

of adults is high in the impoundment. 

Fish Entrainment at Hydropower Projects 
Young sunfish are most frequently found in 

shallow water habitats with at least some 

cover, and when sufficient cover is present, 

they are generally not found in open water. 

Consequently, entrainment rates of sunfish 

at a plant with an intake in open water 

probably would not be high, even when the 

density of adults is near the carrying 

capacity of the impoundment. There is 

insufficient information in the reports about 

habitat near the intakes of the five sites in 

the database for which there are population 

data, however, to test this hypothesis. 

4.4 Suggested Guidelines for 

Determining the Need for 

Entrainment Studies 

The need for entrainment studies 

must be established during the early stages 

of consultations between the 

licensee/applicant and the state and federal 

resource agencies. First, the potentially 

affected resource must be characterized. 

Entrainment studies may not be 

necessary if the impoundment management 

objectives are being met or exceeded. To 

assess this, an up-to-date fisheries 

management plan with specific, quantifiable 

management objectives must be in place. 

Later, management plans may be revised if 

state outdoor recreational studies indicate 

that there is a deficiency in fishing 

opportunities. Revisions to fisheries 

management objectives are normally 

independent of hydroplant operations, 

however, and are supported by demographic 

data. 

Entrainment studies also may not be 

necessary where fisheries resources are not 

exploitable. For example, fishing has been 

banned in the Upper Hudson River where 

there are unacceptably high levels of 

toxicants. In such a case, a restoration plan 

Fish Entrainment at Hydropower Projects 

is established that schedules clean-up and 

follow-up testing to ensure that toxicant 

levels in the environment have returned to 

acceptable levels. Elements in the 

restoration schedule may be used to trigger 

consideration of the need for entrainment 

studies. 

Inaccessibility may eliminate the 

immediate need for an entrainment study. If 

downstream-accessible fisheries depend on 

upstream recruitment of fish that must pass 

by a project, however, the need for 

entrainment studies is greater. 

Entrainment studies also may be 

unnecessary if~ as it is in some cases, some 

cropping of "rough fish" during entrainment 

may improve conditions for other species. 

Sometimes this phenomena combined with 

minor adverse impacts of entrainment on 

existing or proposed fisheries would not 

justify either the cost of studies or installing 

protective measures. 

Occasionally, the potentially affected 

fisheries resource has such a high value that 

protective measures do not need to be 

justified (e.g., on rivers that support 

anadromous populations of Atlantic or 

Pacific salmonids). At these sites, however, 

studies are increasingly recommended to 

evaluate the effectiveness after the protective 

measures are implemented. The potential 

mortality associated with bypass options 

relative to turbine mortality may be a 

consideration. 

If need cannot be ruled out, a study 

may be appropriate to determine whether or 

not the magnitude of the entrainment at a 

specific site warrants protective measures. 

Alternatively, protective measures could be 

installed without conducting entrainment 

studies. 

Page 4-13 
A need assessment first establishes 

what types of protective measures might be 

most effective at a specific site given the 

resources. Resource agencies and other 

parties provide input to estimate the nature 

of the potentially affected resource. Such 

input may include: 1) results of studies on 

the composition of the fish community of 

the impoundment, 2) fisheries management 

plans, 3) recent creel census data, 4) 

stocking records, 5) water quality and 

sediment testing results, and 6) rare species 

records. 

The licensee/applicant and/or 

resource agencies may suggest protective 

measures that seem feasible for the physical 

configuration of the power plant and its 

electrical generation objectives. One or two 

reasonable protective measures may be 

agreed upon for further exploration based on 

studies at similarly configured projects. 

Francfort et al. (1994) indicate that 

for a typical 10 MW project generating 41 

million kWh/year, installation costs of a 

screen/bypass system would average about 

$600,000, and total annual costs would 

average about $82,000 for the first 20 years 

of operation. Installation of angled racks at 

an identical project would average 

$220,000, and total annual costs would 

average $25,000. · Francfort et al. (1994) 

also provide costs for downstream protective 

measures versus plant generating capacity, 

which can serve as a basis for preliminary 

decisions on whether to further explore 

protective measures or consider conducting 

entrainment studies. 

Estimated conceptual costs for the 

most reasonable protective measures then 

should be developed. The design costs 

associated with developing such estimates 

typically range from $1,500 to $20,000, 

unless the proposed protective measure 

Page 4-14 

involves research and development (see 

Tables 3-12 and 3-13). Conceptual costs 

probably will include: 

• the capital costs associated 

with installing the protective 

measure; 

• an accurate estimate of 

operation and maintenance 

costs during the term of the 

new license; 

• 

• 

the costs of lost generation 

during construction and 

operation; and 

the expected cost of 

evaluating the effectiveness 

of the protective measure, if 

recommended, based on 

current agency policy in the 

region. 

The conceptual costs associated with 

implementing a protective measure can be 

compared to the potentially achievable 

resource benefit. If the potential resource 

benefit justifies the protective measure, the 

licensee/applicant may forgo entrainment 

studies and install the measure. If the 

potential resource benefit is uncertain, but 

has a good likelihood of justifying the 

protective measure, then installation costs 

can be compared to the estimated costs of 

conducting entrainment studies. Most 

entrainment studies that have gained agency 

approval involve either netting or netting 

combined with hydroacoustics. The costs 

associated with such studies vary but often 

range between $300,000 and $500,000 (see 

Table 3-11). These are probably minimum 

costs, given recently issued guidelines for 

conducting entrainment studies in Michigan, 

Wisconsin, and Pennsylvania and the 

potential that additional assessments would 

Fish Entrainment at Hydropower Projects 
be recommended if parts of the original 

study are not conclusive or do not meet with 

agency approval. 

Estimated costs for entrainment 

studies can be reduced considerably if 

extrapolation of study results to other sites is 

appropriate. 

4.5 Suggested Guidelines for 

Conducting Entrainment Studies 

When the need to conduct sitespecific entrainment studies is clearly 

identified, methods to achieve study 

objectives should be established. A 

standardized approach to methods and 

reporting entrainment data at specific sites 

may allow meaningful comparisons with 

other studies. Progress towards such 

standardization has been made in Michigan 

and Wisconsin with the issuance of the 

"Joint Agency Fish Entrainment/Turbine 

Mortality Study Plan Guidelines" by the 

USFWS and the Wisconsin and Michigan 

Departments of Natural Resources (1992). 

Some standardization 

recommendations may be applied outside of 

a region, but detailed standards are best 

developed regionally to account for local 

resource values. We recommend flexible 

guidelines that can be modified based on 

consultations between the licensee/applicant 

and the resource agencies. Sampling 

conditions are often unique, however, and 

may require deviations from a standardized 

sampling protocol so that study objectives 

can be achieved. Licensees/applicants and 

the agencies should agree on as many study 

details as possible before the study begins to 

ensure that the collected data address project 

objectives. FERC is available to resolve 

disputes if study plans or need for studies 

cannot be agreed upon. 

Fish Entrainment at Hydropower Projects 

Before a study begins, the minimum 

size of fish to include in the entrainment 

estimate must be defmed. USFWS et al. 

(1992) suggested limiting entrainment 

estimates in Michigan and Wisconsin to all 

fish greater than 1.5 inches (38 mm) long. 

Adoption of this criteria would have· 

substantially reduced the annual entrainment 

estimates at the three Wisconsin River sites 

in the database. It would have increased 

annual entrainment estimates at those sites 

where the minimum detectable fish, based 

on hydroacoustic techniques, were 

considerably greater than 1.5 inches. 

If hydroacoustic estimates are 

adjusted using representative net collections 

(as was done in several studies at South 

Carolina sites conducted by Duke Power), 

then annual entrainment rate is less likely to 

be underestimated. Regardless of minimum 

fish size, the estimates are most useful when 

results can be compared regionally and/or 

basin-wide. 

The most appropriate method for 

collecting entrainment samples at a specific 

site, usually netting and/or hydroacoustic 

techniques, must be identified. Each 

method has advantages and disadvantages, 

and, frequently, combining both techniques 

can minimize disadvantages. Major 

advantages of netting are that data on 

species, size classes, and (when tailrace 

netting is used) condition of entrained fish 

can be obtained. Disadvantages include 

high cost (which frequently limits the 

temporal coverage of sampling), potential 

damage to otherwise healthy fish from 

collection and handling, and uncertainty of 

results (intrusion of non-entrained fish and 

escapement of entrained fish from the net). 

Advantages ofhydroacoustic methods 

are that information on entrainment can be 

collected over a much broader temporal and 

Page 4-15 
spatial spectrum than is practical for netting, 

there is no collection mortality of fish, and 

the cost of studies is generally less than for 

netting. Disadvantages include uncertainty 

as to the species of fish detected, inability to 

effectively sample in high noise situations, 

occasional false fish counts, and use of a 

complex technology that requires specialized 

training. Also, agencies that review results 

sometimes are unwilling to accept 

hydroacoustic entrainment results (see 

Appendix 3.2). 

Much recent resource agency 

reluctance to accept hydroacoustic 

entrainment estimates is based on "Acoustic 

Estimation of Fish Entrainment, Analysis of 

Sources of Error - With Special Reference to 

Wisconsin Entrainment Projects" (Thome, 

1992). This report, prepared for the 

Wisconsin Department of Natural 

Resources, highlights potential sources of 

error in unattended hydroacoustic studies 

conducted in the midwest during the mid- to 

late 1980's. Many problems originated 

from applying hydroacoustic approaches that 

were successful on large, western rivers 

(such as the Columbia River) to small 

hydropower plants typically found in 

Wisconsin. Entrainment at Wisconsin 

hydropower projects is more complex than 

at most western sites because there is often 

more noise; surface-oriented intakes and 

resultant potential for false counts from air 

bubbles and ice break-up; increased fish 

species of concern; variable size and 

behavior of entrained fish; the need to 

conduct studies for much of the year rather 

than just during salmonid outmigration 

periods; and operational differences that can 

create false counts, such as trashrack 

cleaning with rakes or air jets. Thome 

(1992) emphasizes that, when comparing 

acoustics and netting, costs, achievable 

precision, and fish mortalities must be 

considered. He indicates that, in most 

Page 4-16 

cases, inaccuracies in hydroacoustics can be 

overcome by proper experimental design. 

This may increase cost of hydroacoustic 

studies at midwest sites (and other locations 

with similar characteristics). Thome 

contends, however, that properly designed 

hydroacoustic studies can produce more 

accurate entrainment estimates than netting 

studies of similar (or greater) cost. 

Studies in the· database indicate that 

it may be inappropriate to assume that the 

entrainment rate at a sampled unit is similar 

to that at unsampled units, especially if one 

unit is located along a shoreline and the 

others are located mid-river, or if the intake 

structure is parallel to the prevailing flow. 

Entrainment rate at one unit is more likely 

to be similar to another unit if both are 

located at mid-river; this cannot, however, 

be confmned with available information. If 

there is more than one operating turbine, 

sampling at least two turbines may be 

appropriate unless a basis can be agreed 

upon for sampling only one unit. Sampling 

at one unit should produce a conservative 

estimate of the entrainment rate (higher or 

equal to actual entrainment rates) when 

extrapolated to the other units. 

Where several intake structures 

extend from near the shoreline, sampling the 

shoreline intake alone may yield a 

conservative entrainment estimate. Two 

studies in the database (Shawano and 

Greenup Lock and Dam) support this 

approach. Several other studies suggest that 

more fish are entrained adjacent to 

structures (i.e., walls) than in open areas, 

which also may support sampling at 

shoreline-oriented intakes because the 

shoreline would also represent a structure. 

Also, many species of fish (e.g., 

centrarchids, pickerel, and minnows) are 

more often found in near-shore habitats. If 

an impoundment is dominated by such 

Fish Entrainment at Hydropower Projects 
species, sampling only a shoreline intake 

may provide the most conservative estimate. 

If an intake is parallel to the 

prevailing flow, netting may be appropriate 

at more than one turbine to account for 

species-specific behavioral patterns that 

would not be detected by hydroacoustics. 

For example, minnows seemed to be 

entrained at the upstream portion of the 

intake at Station 26, whereas gizzard shad 

were entrained at the downstream end. 

The number of units to be sampled is 

best agreed upon during agency 

consultation. When only net collections are 

used, assumptions necessary to extrapolate 

to unsampled units can be identified before 

beginning the study. 

Using hydroacoustics along with 

netting may be a cost-effective method for 

accurately estimating entrainment rates at 

plants with multiple units. For example, the 

Beaver Falls study indicates that unitspecific entrainment rates may be 

substantially influenced by whether or not 

the adjacent unit is operating. When the 

adjacent unit was operating, the overall 

entrainment rate declined substantially. 

Extrapolating from one unit to the other in 

this case, according to the consultant 

conducting this study, would have been 

unrealistically conservative. The operational 

status of each turbine during sampling must 

be accurately documented, even if each unit 

is not sampled. 

Feasibility of the proposed sampling 

technique at each site can be verified by 

what USFWS et al. (1992) call a "proof-ofconcept" (POC) study. Sometimes after a 

study is completed, the licensee/applicant 

and/ or the agencies note that the results of 

one or more aspects of the study were not 

usable. If a brief POC study had been 

Fish Entrainment at Hydropower Projects 

implemented to verify effectiveness frrst, 

considerable time and expense could have 

been saved. POC studies are best conducted 

when a sufficient quantity of entrainable fish 

are expected at the site. Monthly 

entrainment data in the database provide 

guidance as to when entrainment rates may 

be highest in different parts of the country. 

Alternatively, hatchery fish can be used as 

long as their size and behavioral 

characteristics are representative of fish 

likely to be entrained. The results of POC 

studies can be reviewed by appropriate state 

and federal agencies and the methodology 

approved before beginning the entrainment 

study. 

4.5.1 Guidelines for Netting Studies 

A major advantage of sampling with 

nets is that the species and size distribution 

of entrained fish can be characterized. 

Voucher specimens of each species 

captured, except for rare or endangered 

species, can be preserved to verify 

identifications. 

Full-Flow Tailrace Net Installations 

The most reliable entrainment data 

are obtained when the entire flow exiting 

from at least one turbine is sampled. The 

net is usually attached to a rigid frame that 

is securely positioned against the tailrace 

bay of the powerhouse (dewatering slots, if 

present, are often an ideal anchoring 

location for the frame). Attaching the 

netting directly to the powerhouse at a few 

points, as was done at Constantine, may 

cause the net to billow and potentially 

increase escapement and intrusion of fish, 

thereby lowering net collection efficiency. 

Before fmalizing the tailrace position 

to be sampled, the tailrace can be surveyed 

by divers during the POC study to identify 

Page 4-17 
underwater obstructions that could damage 

the nets and invalidate sampling. Most 

collection nets have at least a 1 :3 width-tolength ratio, which enables definition of the 

area to be surveyed by the diver. If 

obstructions cannot be moved, the sampling 

location may need to be altered. If not 

possible, heavy canvas can be installed on 

the outside of the net to reduce damage, but 

the nets must then be checked for damage 

frequently. Once the net is in place, it can 

be checked by a diver for any gaps between 

the netting and the powerhouse. Gaps then 

can be sealed before sampling begins using 

sandbags, metal panels, PVC pipes, foam 

seal, or rubber boots (EPRI, 1992b). 

Partial-flow Net Installations 

Sometimes it is not possible to install 

full-flow tailrace nets, e.g., at plants with 

high discharges or tailraces that are 

inaccessible for safe sampling. Partial-flow 

netting may be the only alternative. Partialflow netting ideally should be placed in front 

of the turbines where the water velocity is 

such that ftsh are committed to entrainment 

(usually 3 to 6 fps, depending on the species 

of concern). Flow meters installed in 

forebay nets can document the velocity and 

compare it to typical swimming speeds 

(burst speeds) of collected fish. 

Unfortunately, the preferred high-velocity 

sampling zone often is behind the 

trashracks, which can cause serious damage 

to the turbines if nets break loose; use of 

sturdy nets will reduce this potential. At 

some plants, a stationary screen behind the 

nets can be installed during sampling to 

minimize the risk of turbine damage. 

Because samples collected in front of the 

trashracks may sample ftsh not committed to 

entrainment, water velocity data at the 

collection point is especially important. 

Such data can be used to assess the degree 

Page 4-18 

to which non-entrained ftsh may influence 

entrainment rate estimates. 

Partial-flow netting is least effective 

in the tailrace because it is not possible to 

distinguish tailrace intruders from entrained 

ftsh, which can seriously affect the accuracy 

of the data. 

Net Design 

Although the studies in the database 

provide general characteristics for the design 

of entrainment nets, site-specific conditions 

often dictate fmal net design. Many fullflow netting studies in the database used a 

larger meshed chaffmg net (0. 75- to 1.50-

inch bar mesh) to cover and protect a fmer 

meshed collection net from the considerable 

turbulence full-flow tailrace nets are subject 

to. This fmer meshed net sometimes lines 

the entire net, and sometimes only the rear 

half or third of the net. 

Mesh sizes cited in the database 

ranged from 0.25-inch bar mesh (at nine 

sites) to 1.5-inch bar mesh (at Escanaba 

dams 1 and 3). USFWS et al. (1992) 

guidelines for Michigan and Wisconsin 

specify 0.25-inch bar mesh knotless nylon 

nets. Using a small meshed net limits 

intrusion or extrusion of ftsh through the 

mesh. The extra drag created by the small 

mesh could increase net billowing, however, 

especially at high discharges, and may force 

entrained ftsh through any small gaps 

between the net and the powerhouse. 

Maintaining a small meshed net in a 

high discharge tailrace may be difficult if 

not impossible because of excessive drag. 

Eight of the nine sites that used 0.25-inch 

mesh indicate that the flow through each net 

ranged from 180 cfs (Tower) to 

approximately 600 cfs (Crowley) and 

averaged 360 cfs; through-net flow could 

Fish Entrainment at Hydropower Projects 
not be estimated at King Mill. Collection 

efficiency at these sites was high, and at 

Tower, Kleber, Crowley, and Shawano it 

exceeded 80 percent. At Buchanan, 

Constantine, and French Landing (a partialflow tailrace netting site), collection 

efficiency was generally under 60 percent, 

which could reflect drag-related problems. 

The results at Crow ley indicate that 

it is possible to successfully use 0.25-inch 

knotless nylon mesh nets under conditions 

that sample up to 600 cfs if the net is 

sturdy. The net showed obvious signs of 

stress, and an extension was added to reduce 

the stres$ on the mesh and frame attachment 

points. Increasing the length of the net 

effectively allows 0.25-inch mesh to be used 

under relatively high flow conditions. When 

through-net flows exceed 500 cfs, an 

evaluation of netting with a full 0.25-inch 

mesh liner may be needed in the POC study. 

A removable liner in the front portion of the 

net allows a relatively inexpensive 

evaluation of both netting options. 

The most appropriate mesh size is a 

function of site-specific conditions and study 

objectives. Sampling difficulty is more 

likely to be a factor, however, when 0.25-

inch mesh is used. If large fish entrainment 

is the primary study objective, using a larger 

mesh size for netting studies could produce 

more representative results. Interpreting the 

importance of collecting large quantities of 

small fish is difficult because entrainment 

survival of small fish is typically high. The 

population impacts of limited entrainment 

mortality on small fish are questionable. 

Tailrace nets can be equipped with 

live cars to allow fish to be returned to the 

river unharmed after processing, provide 

fish to be used in collection efficiency 

studies, and enable assessment of turbine 

mortality. EPRI (1992b) describes typical 

Fish Entrainment at Hydropower Projects 

live-car construction. Sewing a fyke into 

the rear portion of the net will minimize 

potential for collected fish to escape. Also, 

many collection nets used in database studies 

were dark colored which reduced the 

potential for fish avoidance. 

Tailrace Net Presample Flushing 

Before tailrace net sampling begins, 

the unit to be sampled is normally shut 

down to install the nets. When the unit is 

restarted, the nets are usually set for a brief 

period to allow non-entrained fish to be 

flushed from the net before sampling. The 

amount of time used to flush the nets varied 

from 15 minutes at studies conducted by 

Duke Power to several hours at Crowley. 

The time needed to flush tailrace residents 

from the tailrace bay depends on the plant 

configuration; plants with areas of dead 

water or eddies would be expected to take 

longer to flush than more streamlined 

arrangements. Fish collected during 

flushing should be counted and recorded to 

indicate the adequacy of the flushing period. 

Low numbers of fish in the flush sample 

suggest that the duration of the flush sample 

is appropriate. If a flush sample has an 

uncharacteristically high number of fish 

relative to previous flush samples, the 

flushing period may need to be lengthened. 

Exclusion of Fish From Entrainment 

&timates 

Most netting studies exclude certain 

fish from the entrainment estimates based on 

criteria that identify the fish as not having 

been entrained. Exclusion criteria include 

fish that are too wide to fit through the 

trashracks (determined by direct 

measurement or by developing speciesspecific length-width relationships based on 

representative samples) and fish that are 

known to occur only in the tailwaters. 

Page 4-19 
Accepting these exclusions acknowledges 

tailrace intrusion of fish, however, which 

raises questions about the adequacy of the 

seal of the net against the powerhouse. 

The licensee/ applicant and agencies 

should agree which fish can be appropriately 

excluded from the entrainment estimate 

during study design consultations. 

Performance standards can be developed 

early in the sampling program to specify 

corrective actions if the number of tailrace 

intruders becomes excessive. Some 

entrainment studies also excluded fish that 

were "obviously dead prior to entrainment. " 

This rna y be appropriate for fish that are 

decomposing at the time of collection, but 

can be subjective for fish that have not been 

dead for long. The criteria characterizing 

fish that are dead before entrainment can be 

established before study implementation or 

as soon as a problem is noted. 

At some sites (e.g., Youghiogheny 

and Buzzard's Roost), entrainment rates 

increased substantially during the winter. 

The licensee/applicant hypothesized that 

many of these fish were thermally stressed 

and either dead or dying when entrained and 

that inclusion of these fish in assessing 

impact of the hydroelectric plant was 

inappropriate without substantive evidence; 

agencies may not support this approach. 

Continuously monitoring forebay water 

temperature during the winter and forebay 

netting at a location where the velocity is 

low enough to enable healthy fish to escape 

may help support the licensee/applicant's 

case. 

Net Efficiency Studies 

Net efficiency studies help determine 

what proportion of fish passing through a 

turbine are collected by the sampling net. 

Results of these studies are used to adjust 

entrainment rate estimates to account for 

Page 4-20 

fish that escape collection and to trigger 

repairs to the net or other corrective 

measures. 

Efficiency tests are most useful if 

conducted regularly and should use both live 

and dead fish that represent the sizes and 

species of fish likely to be entrained. Test 

fish should be marked and measured to 

distinguish them from non-test fish. Test 

fish may be either of wild or hatchery 

origin, and resource agencies should be 

consulted to select representative species and 

sizes. Incorporating at least one net 

efficiency study into the POC study is 

appropriate. 

Test fish are released either directly 

in front of the turbines, the mouth of the 

collection net, or both; the most appropriate 

location depends on site-specific conditions. 

Most database studies (12 of 21) released 

fish in front of the turbines. Throughturbine releases most closely simulate how 

naturally entrained fish will be collected and 

can readily be combined with turbine 

mortality studies. Results may be inaccurate 

if fish are released where the velocity is 

insufficient to ensure that all fish are 

entrained (a parameter not readily quantified 

when live fish are released), fish passage is 

delayed due to back-eddies or areas of dead 

water within the plant (as at Tower and 

Kleber), or if sampled and unsampled 

tailrace bays are interconnected. 

Releases directly into the mouth of 

the net provide greater assurance that fish 

will be collected and that they cannot escape 

before passage through the turbines or via 

unsampled turbine bays. Fish released into 

the mouth of the net may not behave the 

same as entrained fish, however, and the 

spatial distribution of fish released at a 

single point may be different from entrained 

fish, especially if the point of release is not 

Fish Entrainment at Hydropower Projects 
appropriate. Through-turbine releases are 

preferable to net-mouth releases if a review 

of the plant configuration (diagrams and site 

visits) indicates that the above-mentioned 

disadvantages can be minimized. For 

example, fish released into a net can be 

released at the point of maximum velocity 

(as determined by flow meter). 

Test fish can be introduced via a 

suitably designed system that ensures all fish 

are released at the designated location. 

Typical release systems include a test fish 

holding tank, tubing from the tank to the 

release point, and a flushing mechanism or 

plunger. Test releases of at least 50 fish per 

species, and uniform condition (live or dead) 

and size class increase the accuracy of 

results. Control fish are also needed to 

accurately assess turbine mortality if this is 

a study objective. Separate tests can be 

considered for each collection net. If the 

turbine(s) to be sampled typically operate at 

different hydraulic rates, then tests that 

represent the expected range of flows may 

be appropriate. For full-flow netting, an 

effective collection efficiency exceeds 85 

percent; if it is less than 70 percent, 

corrective action must be considered. 

We recommend at least two separate 

net efficiency studies (including the POC 

study) conducted at roughly evenly spaced 

time intervals. We recommend evaluation 

of net efficiency more frequently (perhaps 

on a reduced scale, using fish collected 

during routine sampling) because corrective 

action needs can be quickly assessed (e.g., 

when a net is tom or the seal between the 

net and the powerhouse is disrupted) and the 

chance that sampling will be invalid is 

reduced. Net efficiency studies were 

conducted once a month at the five Duke 

Power sites in the database. This frequency 

enabled identification of any net problems 

that developed during the study. 

Fish Entrainment at Hydropower Projects 

The availability of appropriate fish. 

on-site sampling conditions (e.g., ice or 

flood flows make sampling hazardous, 

excessive stress to fish), and cost must be 

considered when designing net efficiency 

studies. Such factors influence the number 

of fish per efficiency test release and the 

frequency of testing. 

Collection efficiency data normally is 

used to adjust entrainment rates. Because 

collection efficiency may change over time 

(reflecting changes in plant operating mode, 

condition of the net, and/ or shifts in the size 

or species of entrained fish), the sampling 

period and operating conditions represented 

by each efficiency test is typically specified. 

Collection efficiency for each test species 

and size class is also clearly presented. Test 

species used as surrogates should have 

similar body shapes and swimming ability to 

the species they represent. 

Sampling Schedule 

Specific objectives of entrainment 

studies determine the frequency and duration 

of sampling. An estimate of the annual 

number and sizes of each species of fish 

entrained generally indicates whether 

protective measures are appropriate at a 

specific site. If modifying plant operations 

(e.g., restricting plant operations during 

periods of high entrainment rates) is a 

possible protective measure, however, then 

entrainment rate estimates for more specific 

time periods should be developed (e.g., 

monthly and/or hourly). Monthly sampling 

efforts of studies in the database ranged 

from 1 to 30 days. Generally, 1 day of 

sampling per month characterized periods 

when low entrainment rates were expected 

(usually winter). At some sites (especially 

those dominated by clupeids), however, 

entrainment rates were often the highest 

during the winter, which illustrates the 

importance of acquiring information on the 

Page 4-21 
fish community before designing sitespecific entrainment studies. Sampling 

efforts during spring, summer, and fall 

(periods when fish activity is expected to be 

high) was typically 3 to 6 days per month at 

most sites. 

Derr et al. (1993) discuss in detail 

factors to consider in establishing 

entrainment sampling schedules. Their 

recommendations were based on a review of 

data from the most comprehensive study in 

the database, Youghiogheny. Both units at 

this site were sampled continuously with 

full-flow tailrace nets for 1 year. They 

emphasize the importance of establishing 

decision criteria (such as desired levels of 

precision and acceptable levels of bias) for 

proposed studies by close coordination 

between agency personnel and those 

conducting the studies. Bias can be 

introduced by annual, seasonal, diurnal, sitespecific (i.e., differences between units), 

and net sampling efficiency factors. The 

first three factors are discussed below, the 

other two factors are addressed earlier in 

this section. 

Annual factors can create bias 

relative to whether or not the year selected 

for study is representative of other years. 

To estimate variation from year to year the 

site must be monitored for more than 1 year 

(Derr et al., 1993). Section 3.2.1 indicates 

the nature of variation in entrainment rates 

between years. At sites with more than 1 

year of data, the relative abundance of 

species was generally similar from year to 

year as was the timing and, in some cases, 

the magnitude of seasonal peak entrainment 

rates. Monitoring entrainment for more 

than 1 year is the best way to minimize 

biases due to annual factors, but frequently, 

this may not be practical due to high cost. 

Physical factors, such as river discharge, 

flow through the plant, and/or water 

Page 4-22 

temperature, also may be monitored to 

determine whether the year sampled is 

typical of non-sampled years. If considered 

typical (as defmed by consultation), results 

from one year may be considered 

representative of other years. 

Seasonal bias factors can be 

considered if sampling efforts vary for each 

month. Derr et al. (1993) emphasize the 

importance of using available regional data 

and expert opinions to help minimize this 

type of bias. They also indicate that using 

a flexible sampling program enables the 

sampling regime to be adjusted based on the 

results of POC studies (referred to by Derr 

as pilot studies). For example, if sampling 

is proposed for 1 or 2 days a month during 

winter and the first sampling effort shows a 

collection of large numbers of fish, it would 

be appropriate to increase the level of 

sampling. 

Maximizing precisiOn while 

minimizing the amount of sampling depends 

on the "autocorrelation" relationship of 

entrainment (Derr et al. , 1993). 

Autocorrelation, which is the dependence of 

one day's counts to the counts on a 

subsequent day, also affects the precision of 

the estimate of monthly mean entrainment 

rates. Derr et al. 's analysis of the 

Youghiogheny data for December and 

January suggested that there was strong 

autocorrelation during these 2 months. 

Given this dependence, sampling at regular 

rather than consecutive intervals would 

increase the precision of the entrainment rate 

estimate with the least amount of sampling 

effort and provide narrower confidence 

intervals. At Youghiogheny, sampling 

every fifth or sixth day (5 or 6 days per 

month) would have produced an adequately 

precise (conforming to pre-established 

criteria) estimate of the mean entrainment 

rate. This sampling frequency also would 

Fish Entrainment at Hydropower Projects 
probably have detected peak entrainment 

events at Youghiogheny. 

USFWS et al. (1992) guidelines for 

Michigan and Wisconsin specify conducting 

net sampling for 3 days a week at each unit 

sampled from April to October, and 3 days 

every 2 weeks for the rest of the year. The 

impact to entrained fish of sampling at such 

frequent intervals may be considerable, 

given the stress and mortality often 

associated with net sampling, and the costs 

associated with such a rigorous sampling 

regime should be considered. 

H netting is used to verify 

hydroacoustic sampling, USFWS et al. 

(1992) recommend 1 day per week from 

April to October and 1 day every other 

week for the rest of the year. Derr et al. 

(1993) stress the importance of having a 

statistician work with biologists to design the 

appropriate sampling frequency. 

Based on the prevalence of sites in 

the database with episodic entrainment, we 

recommend spacing sampling days at regular 

intervals rather than consecutively. The 

number of days sampled per month can 

balance good experimental design with the 

sample collection cost. We also recommend 

that a sample consist of no more than 24 

hours of data collection, which will 

standardize collection efforts. Sampling for 

several days without checking the nets can 

cause nets to become clogged with debris 

and increase mortality of fish collected due 

to sampling-related stress. Results of such 

collections may not be comparable to results 

from samples collected for up to 24 hours. 

Millville was the only other site 

(besides Youghiogheny) where a sufficient 

number of days were sampled with a fullflow net to evaluate the effect of sampling 

frequency on the accuracy of entrainment 

Fish Entrainment at Hydropower Projects 

rate estimates. We performed a cursory 

analysis using the 1991 Millville data (Table 

4-1) to assess the error associated with 

sampling 3 randomly selected days per 

month versus 3 consecutive days. We 

selected 5 months in which over 10 days of 

sampling was performed for this analysis 

(range: 11 to 25 days). Ten trials were 

performed in which 3 days were randomly 

selected from each month's data (data were 

not available to allow selection of uniformly 

spaced sampling dates), and we performed 

another 10 trials in which we randomly 

selected a string of 3 consecutive days (or as 

close to consecutive as the data allowed). 

We compared the average 

entrainment rate over the 15 days selected in 

each trial to the average of the monthly 

entrainment rates using all available data. 

The degree of error (deviation from the 

mean using all data) averaged 8.65 percent 

(range: 1.4 percent to 17.7 percent) when 

we randomly selected the three individual 

sampling dates per month. The average 

error increased to 35.3 percent (range: 9.3 

percent to 100.5 percent) when we selected 

strings of 3 consecutive days. The error for 

estimates of the entrainment rate for 

individual months or species of fish is likely 

to be greater. This analysis supports Derr 

et al. 's conclusion that the error can be 

reduced substantially by avoiding sampling 

on consecutive days. It also indicates the 

level of error associated with sampling 3 

consecutive days per month, which has been 

used in many of the studies conducted to 

date. Sampling on nonconsecutive days 

generally increases the cost of an 

entrainment study, but costs may be offset 

by sampling fewer days while maintaining 

or decreasing estimate error. 

Page 4-23 
TABLE 4-1 

1991 MJLLvn.LE ENTRAINMENT DATA USED TO EVALUATE THE ERROR 

ASSOCIATED WITH SAMPLING THREE DAYS PER MONTH (CONSECUTIVE 

OR INDEPENDENT) SOURCE: EEM (1992) 

~gUe!i~isms ~2ll~!i~12D~ ~glhc~ion~ 

Pate I.llh .l:l.2..!u:i pate I..Uh fuu&ll Pate I.llh ~ 

l/24/91 5 23.8 6/10/91 476 24.3 10/14/91 22 22.7 

l/25/91 15 19.0 6/12/91 88 21.8 10/15/91 44 22.5 

1/29/91 2 25.8 6/15/91 167 21.6 10/16/91 36 23.1 

1/30/91 1 25.0 6/18/91 64 23.8 10/17/91 li 24.8 

l/31/91 1 24.0 6/19/91 76 23.8 10/18/91 25 23.6 

2/02/91 1 18.6 6/20/91 77 24.1 10/19/91 26 22.9 

2/03/91 0 19.6 6/21/91 89 23.8 10/20/91 29 24.2 

2/04/91 0 20.6 6/22/91 71 20.0 10/21/91 43 24.3 

2/05/91 1 24.0 6/23/91 166 24.3 10/22/91 16 23.7 

2/07/91 0 23.6 6/24/91 110 25.1 10/23/91 17 21.1 

2/08/91 0 24.6 6/25/91 37 23.8 10/24/91 2 22.4 

2/09/91 2 24.5 6/26/91 103 23.9 10/31/91 44 27.7 

2/10/91 0 23.8 6/28/91 2 22.1 11/01/91 34 15.7 

2/11/91 3 24.2 7/03/91 45 21.5 11/02/91 59 24.7 

2/14/91 1 21.0 7/04/91 39 24.2 11/03/91 34 23.8 

2/15/91 1 19.2 7/05/91 98 23.4 11/04/91 34 24.7 

2/19/91 2 23.9 7/09/91 54 23.1 11/05/91 22 25.5 

2/20/91 3 24.2 7/16/91 217 22.5 11/06/91 37 24.8 

2/22/91 1 23.9 7/17/91 15 23.0 11/13/91 18 23.7 

2/24/91 0 25.2 8/20/91 17 24.5 11/14/91 45 24.1 

2/25/91 2 22.3 8/21/91 0 23.7 11/15/91 55 23.7 

2/27/91 0 23.8 8/22/91 0 23.9 11/20/91 16 23.7 

2/28/91 0 23.3 8/31/91 10 24.6 11/21/91 34 22.5 

3/19/91 2 21.2 9/01/91 17 23.8 12/03/91 38 23.6 

4/11/91 123 23.9 9/02/91 11 23.7 12/18/91 17 23.5 

4/28/91 18 19.3 9/03/91 34 24.0 

4/29/91 150 27.5 9/14/91 56 16.7 Totals 5320 2615.9 

5/02/91 15 24.3 9/15/91 95 23.4 

5/07/91 62 21.3 9/16/91 120 24.7 

5/09/91 78 22.3 9/24/91 21 23.4 

5/10/91 91 20.8 9/26/91 19 23.7 

5/ll/91 28 20.8 10/01/91 20 24.8 

5/14/91 1 24.2 10/02/91 46 24.7 

5/16/91 182 22.0 10/03/91 102 22.7 

5/17/91 127 20.2 10/04/91 118 21.6 

5/21/91 11 24.3 10/05/91 24 20.2 

5/24/91 20 24.2 10/06/91 64 23.4 

5/25/91 82 21.5 10/07/91 188 23.1 

5/29/91 16 20.7 10/08/91 98 24.4 

5/30/91 54 24.3 10/09/91 15 22.2 

5/31/91 61 24.2 10/10/91 44 24.4 

6/07/91 39 20.3 10/11/91 35 24.0 

6/08/91 69 24.0 10/12/91 32 27.3 

6/09/91 78 23.7 10/13/91 28 23.0 

Page 4-24 Fish Entrainment at Hydropower Projects 
Johnson et al. (1994) found that 

increasing the number of days sampled had 

diminishing value in improving the precision 

of the entrainment estimate. They also 

found that the precision of the estimate 

varied by season and site. 

Derr et al. (1993) suggest evaluating 

the proposed sampling schedule in the POC 

study if sampling for less than 24 hours is 

proposed. We found, however, that diel 

entrainment rates changed between species 

and sampling months too often to suggest 

that sampling is not necessary during any 

part of the day at a specific site (see Section 

3. 2.1). Data on diel patterns can be 

obtained during 24-hour sampling because 

samples are usually regularly removed from 

the nets to minimize collection stress to fish. 

If such data indicate a strong diel trend at a 

specific site, the feasibility of adjusting daily 

plant operations to minimize entrainment can 

be evaluated. Such trends, however, were 

uncommon across species for sites that we 

evaluated. 

4.5.2 Guidelines for Bydroacoustic 

Studies 

Fixed-location hydroacoustic 

techniques can effectively document the 

number and behavior of fish passing through 

hydroelectric projeets. Extensive data can 

be collected on both temporal and spatial 

aspects of entrainment. Behavioral aspects 

of fish entrainment (such as depth or 

location of entrainment) can be used to 

determine the most effective types of 

protective measures at a specific site. These 

specific temporal and spatial data are rarely 

available from netting studies. 

The success of entrainment studies 

that rely on hydroacoustic equipment, 

however, depends on the proper deployment 

of systems, collection of data, and data 

Fish Entrainment at Hydropower Projects 

analysis. The equipment must be state-ofthe-art and operated by properly trained 

personnel (HTI, 1993). We recommend 

professional training for all individuals that 

operate hydroacoustic equipment, review 

hydroacoustic study plans, and/or intetpret 

the results of hydroacoustic surveys. EPRI 

(1992b) presents a summary of 

hydroacoustic methods. In the following 

section we describe variables that must be 

included when documenting hydroacoustic 

studies. 

The areal coverage of hydroacoustic 

transducers is a function of the effective 

beam width, which is determined by the 

acoustic size of the target and the distance 

from the transducer (HTI, 1993). Studies 

should document the effective beam widths 

for different target strengths and ranges. 

Near- and far-field eusonified zones 

must be clearly defmed during the POC 

study. The minimum area of the intake to 

be ensonified should be based on what can 

be sampled effectively at a specific site and 

the cost versus sampling bias of a given 

ensonified field. 

The optimal position for transducer 

placement is as close to the turbines as 

possible while preventing turbine "noise" 

from affecting data intetpretation. This 

reduces the likelihood that fish entering the 

ensonified field that are not entrained will be 

counted. Water velocity of the ensonified 

field is typically either measured or 

calculated based on intake dimensions and 

turbine hydraulic capacity for each 

transducer. 

USFWS et al. (1992) recommend 

operating each transducer for a period of no 

less than 30 minutes every hour and 

monitoring 24 hours a day for a least 1 

year. Although studies in the database do 

Page 4-25 
not give the costs, such a sampling regime 

is conservative and allows 

licensees/applicants to minimize their initial 

costs by evaluating some of the data later. 

The rna jor cost element associated with 

hydroacoustic studies is data analysis and 

reporting. If diel entrainment patterns are 

not part of project objectives, sampling 

frequency sometimes can be reduced. Sitespecific hydroacoustic sampling frequencies 

may be agreed to during agency 

consultations. 

Most hydroacoustic studies in the 

database sampled 24 hours each day. At 

Station 26, sampling was done virtually 

year-round except when the units were offline. At Tower, Kleber, and Moores Park, 

sampling was done 5 days a week during 

specific periods (every other week or 

seasonally). 

Generally, single-beam transducers 

with tracking can be used to estimate 

entrainment rates because they are less 

sensitive to noise and enable clearer 

defmition of the ensonified area; however, 

at least one dual beam or split beam 

transducer per site would enable 

development of a target strength distribution 

(convertible to fish length distribution) and 

effective beam width (convertible to 

direction of travel), if this measure is 

needed (HTI, 1993; USFWS et al., 1992). 

Before beginning a study, 

hydroacoustic instrument specifications and 

proposed operational characteristics should 

be agreed upon. Systems normally include 

accurate time varied gain capabilities. 

During planning, the pulse length, pulse 

repetition rate (generally no less than 10 

"pings" per second), echo signal processor 

sampling rate, and echo-sounder frequency 

should be established. Hydroacoustic 

equipment should be calibrated m 

Page 4-26 

accordance with manufacturers' 

recommendations and protocols agreed upon 

during consultations. Transducer calibration 

and overall gain measurement typically 

require the equipment to be returned to the 

manufacturer or a qualified acoustic 

laboratory (HTI, 1993). Documentation of 

the calibration process along with calibration 

sheets should be included in the study 

report, in a pre-approved format. Examples 

of calibration information developed during 

previous studies can be used for mutual 

concurrence or proposed modifications 

during study planning. 

Site-specific noise levels in each 

turbine bay should be measured during the 

POC study and transducers placed to 

optimize detection of the smallest fish 

included in the study (USFWS et al., 1992). 

Target -tracking procedures that are proposed 

to distinguish fish from noise or debris, 

including the use of filters, should be agreed 

upon before the entrainment study (USFWS 

et al., 1992). If noise at a specific site 

makes detection of small fish uncertain, 

length-frequency distribution data from net 

sampling (as done for studies in South 

Carolina) may be acceptable. 

Proposed data extrapolation 

procedures are less likely to be 

misunderstood if explained in the study plan. 

Proposed statistical techniques agreed to by 

the appropriate agencies also are typically 

clearly defmed in the plan. 

Hydroacoustic sampling nearly 

always is best accompanied by net sampling 

to determine the species composition and 

length-frequency distribution of entrained 

fish. Exceptions to this are rare and require 

acceptance of assumptions (e.g., that nearly 

all fish detected are of a certain species or 

that taxa entrained are similar to that at 

other facilities where net sampling was 

Fish Entrainment at Hydropower Projects 
conducted) that are best agreed to by the 

fish and wildlife agencies. If the 

licensee/applicant cannot agree on this or 

other study design elements, the FERC 

resolution process can be used to fmalize the 

study design. 

Net sampling also helps to verify the 

hydroacoustically derived entrainment rate 

estimates. Net verification was effective at 

some sites in the database (e.g., Tower, 

Kleber, and several of the Duke Power 

sites) but not at others. Estimates that 

cannot be verified are usually attributed to 

sampling biases in either the hydroacoustic 

or netting component of the study. 

Verification netting typically is used at 

unit(s) that are hydroacoustically sampled 

with net sample duration generally 

corresponding as closely as possible to the 

actual time that transducers are sampling 

that unit. 

If hydroacoustic entrainment rate 

estimates vary substantially from net-derived 

entrainment rate estimates, one of the two 

techniques probably is providing false 

values. Equipment should be checked and 

repairs and adjustments made as appropriate. 

Some differences between the two 

techniques, however, are expected in all 

cases. It is unlikely that intrusion and 

extrusion can be completely eliminated from 

net sampling, and it is rarely possible to 

ensonify 100 percent of a turbine intake, so 

hydroacoustic counts must be extrapolated to 

unsampled areas. During study design, the 

agencies and the licensee/applicant should 

agree on the limits of variability and what 

will be done if the results exceed these 

limits. Hydroacoustic entrainment rate 

estimates can be compared regularly with 

netting data (e.g., on a monthly basis) to 

identify corrective action before the study is 

completed. 

Fish Entrainment at Hydropower Projects 

As discussed above, hydroacoustic 

monitoring techniques are almost always 

used in conjunction with netting techniques. 

It may, therefore, be more appropriate to 

use hydroacoustics to supplement netting 

studies, rather than the converse. This 

approach, which was used at Crowley, 

combines attributes of both methods. At 

Crowley, hydroacoustics were used to 

monitor the number of fish entrained at both 

units. The number of fish of each species 

that were entrained at the unit not sampled 

was estimated as follows: 

ENTRAIN unit A = NETCOUNT Unit 8 X 

(HACOUNT Unit A/HACOUNT Unit 8) 

where: 

ENTRAINunitA = the number of a 

particular species 

entrained at the unit 

not sampled by nets; 

NETCOUNT unit 8 = the number of a 

particular species 

entrained at the unit 

sampled by nets; 

HACOUNT Unit A = the total number of 

fish entrained at unit 

not sampled by nets 

as determined by 

hydroacoustics; and 

HACOUNTurut 8 = the total number of 

fish entrained at unit 

sampled by nets as 

determined by 

hydroacoustics. 

We suggest calculating the ratio 

HACOUNT Unit A/HACOUNT unit 8 at least 

monthly to mmmuze bias because 

entrainment patterns are likely to change 

over time. This method assumes that 

species composition at the unit not sampled 

by nets is similar to the unit sampled by 

Page 4-27 
nets. It avoids the assumption, however, 

that the entrainment rate at an unsampled 

unit is similar to that at a sampled unit. 

4.5.3 Guidelines for Reporting 

Entrainment Study Results 

Entrainment studies estimate the 

number of fish entrained through a 

hydropower project during a specified time 

period. Usually this period is 1 year, but it 

could be less if the plant does not operate 

continuously (e.g., the plant shuts down for 

routine maintenance for I month). We 

recommend monthly reporting of 

entrainment rates (fish/hour) and flows 

through sampled units. Assumptions used to 

account for unsampled periods should be 

clearly stated. 

Data from some studies (i.e., without 

penstocks or power canals) indicate that the 

entrainment rate may not be uniform at 

different hydroplant units. We recommend 

reporting the entrainment rate at different 

sampled units (both monthly and annual 

rates) in addition to the annual entrainment 

rate at the entire project, where applicable. 

Future assessments then can consider unitspecific protective measures. For example, 

if a unit routinely does not operate during 

periods of high entrainment, protective 

measures may not be needed. If a unit 

consistently has higher entrainment rates 

than other units operating during the same 

time, the sequence of turbine operation may 

be modified to minimize entrainment during 

critical periods. 

We recommend reporting annual 

entrainment rates by size interval for each 

species. Because there is little 

standardization in reporting size of entrained 

fish, it is difficult to compare specific-sized 

fish among sites. We suggest adopting the 

length intervals associated with the 

Page 4-28 

replacement values of fish derived by the 

American Fisheries Society in the most 

recent version of "Investigation and 

Valuation ofFish Kills" (American Fisheries 

Society, I99I) as the reporting standard. 

Generally, fish would be reported in l-inch 

size intervals, but size intervals could be 

lumped for certain species, such as clupeids. 

It would not be necessary to measure thE! 

length of certain small species (e.g., most 

species of minnows). 

If this size reporting convention is 

used, the resource value of entrained fish 

can be estimated. Affected resources then 

can be compared among sites. Eventually, 

criteria may be established for determining 

the appropriateness of protective measures to 

minimize entrainment rates based on 

affected resource values. There is no 

universally accepted method to determine 

the value of a fish (Francfort et al., I994), 

and few entrainment studies report 

entrainment rates in a manner that would 

allow comparable resource value 

determinations. 

Recent turbine mortality studies show 

that the number of entrained fish that are 

killed is often relatively small, especially for 

small fish; for many species numbers are as 

low as I to 3 percent (EPRI, I992b). If 

turbine mortality is studied along with 

entrainment, then the value of the lost 

resource can be estimated. The significance 

of these entrainment losses to the fish 

community in the impoundment, however, is 

not readily characterized (see Section 4.3). 

We recommend reporting the 

following environmental variables at least 

daily (agencies may recommend more 

frequent recording) during sample 

collection: 

• total river discharge (cfs); 

Fish Entrainment at Hydropower Projects 
• 

• 

• 

discharge through each unit, 

including those not sampled 

(cfs); 

surface, mid-, and bottom 

forebay temperature and 

dissolved oxygen; and 

water transparency (Secchi 

disk value). 

We also recommend recording the 

amount of time sampled during each day and 

clearly explaining and documenting any 

deviations from the agreed-upon sampling 

protocol. Summary tables of these variables 

should be included in the main body of the 

report; place the raw data as an appendix. 

We further recommend reporting the angle 

of the trashracks relative to the flow into the 

unit and logging weather conditions during 

sampling to be used for explanatory 

purposes, as needed. 

We recommend developing and 

reporting a vertical and horizontal velocity 

profile of the plant unit being sampled. 

The intervals at which measurements are 

recorded depend on site-specific 

characteristics, and the profile should be 

based on measurements taken directly 

upstream of the trashracks. Data should 

clearly specify whether the profile is 

oriented perpendicular to the water surface 

or parallel to the plane of the trashracks. 

Measurements should be taken during low, 

average, and high through-plant discharges. 

We also recommend using average velocity 

values derived from calculations using 

forebay dimensions only to generally 

indicate approach velocity when actual 

measurements are not available or practical. 

The average velocity in the collection nets 

also can be directly measured and reported 

if anything other than full-flow tailrace 

netting is used. For studies using 

Fish Entrainment at Hydropower Projects 

hydroacoustics, velocity profiles also can be 

developed for the ensonified fields using 

direct measurements or calculated values. 

The study report should describe all 

statistical tests used for data analysis, along 

with significance levels and confidence 

intervals and assumptions. All calibration 

data for hydroacoustic equipment can be 

included as an appendix. 

Quarterly progress reports also 

should be submitted to appropriate agencies. 

The frequency of these reports should be 

established during pre-study consultations. 

If there are potential deviations from the 

study plan (e.g., net collection efficiency 

decreases or forebay noise level changes that 

would warrant changing the transducer 

locations in a hydroacoustic study), we 

recommend contacting the appropriate 

agencies as soon as possible. Feedback on 

study results and any deviations from the 

study plan then can be considered when 

planning subsequent sampling efforts, rather 

than after the original sampling effort is 

completed. The feedback should focus on 

study plan interpretation and should not add 

new study components unless agreed upon 

by both agencies and the licensee/applicant. 

Page 4-29 
(this page intentionally left blank) 
5.0 CONCLUSIONS 

As the 45 studies in the database 

demonstrate, entrainment study design and 

implementation vary greatly. Variability is 

a function of the parties conducting the 

studies, site-specific constraints, costs of 

conducting the studies, differing resource 

agency objectives, and the presence or 

absence of precedents and other guidance. 

Entrainment study results also show diel, 

seasonal, spatial, site-specific, and speciesspecific trends. Overall, we were unable 

to detect many consistent statistically 

significant trends, using entrainment rates 

for all species and sizes combined based 

on the variables analyzed. 

Variability attributable to 

differences in sampling methods cannot be 

separated from actual differences in 

entrainment rates. Our review of these 

differences leads us to the most important 

conclusion of this study: Study methods 

and implementation must be standardized 

as much as possible. This report presents 

guidelines to use as building blocks for a 

standard sampling protocol. 

Standardization of sampling is an iterative 

process also, one that requires sharing 

lessons learned from past experience and 

adjusting them as new data are gathered. 

Because of the evolving nature of 

entrainment sampling methods and impact 

assessment, this report should not be 

interpreted by the reader as a FERC 

policy document. 

Presently, extrapolation of total 

entrainment rates from sampled sites to 

unsampled sites may be appropriate in 

some basins. This is especially 

supportable if evaluation of the need for 

protective measures can be based on 

entrainment rates that could be somewhat 

higher or lower than the actual rate at 

Fish Entrainment at Hydropower Projects 

unsampled sites. Lumping of sampled 

sites to exclude sites that are not 

comparable to unsampled sites may 

reduce potential bias. For example, if the 

fish community in a reservoir is strongly 

dominated by clupeids or an upstream 

stocking program, that · site may not be 

very comparable to other sites without 

these characteristics. Additional analysis 

may help eliminate other sites from those 

considered for lumping and extrapolation. 

Site-specific entrainment studies may yield 

more precision at sites with dissimilar site 

characteristics or species composition. 

However, the cost of the studies and the 

expected level of impact would influence 

the decision of whether or not to conduct 

such studies. 

The cost of conducting entrainment 

studies is high, but the cost of installing 

protective measures to mtmmtze 

entrainment rates is generally higher. 

Deciding whether or not site-specific 

entrainment studies are recommended and 

when study results indicate that protective 

measures are necessary may affect a 

project's economic viability. 

The results of new entrainment 

studies could be added to this database or 

a new database developed to incorporate 

standardized fish-length data by species. 

The latter could reduce some of the intersite variability found in our present 

analysis. Increasing the amount of 

available data would improve the 

statistical reliability of subsequent 

analyses. Proposed standardized 

entrainment study protocols can be 

continually updated and made readily 

available to agencies, licensees/applicants, 

and consultants. The Entrainment Review 

Team also may act as a forum to evaluate 

proposed future modifications to 

Page 5-l 
entrainment sampling and analysis 

protocols. 

Because each site is unique, FERC 

staff will continue to assess entrainment 

impacts on a case-by-case basis. If the 

impact on resources at a site is expected 

to be high, accurate entrainment estimates 

will strengthen the basis for determining if 

fish protection is required. In such cases, 

realistic conceptual cost estimates for sitespecific protective measures may provide 

a basis to forgo entrainment studies. If 

anticipated impacts are low relative to the 

costs of entrainment studies or protective 

measures, then neither studies nor 

protective measures may be required. 

Page 5-2 Fish Entrainment at Hydropower Projects 
6.0 LITERATURE CITED 

6.1 Literature Cited in the Interpretive Report 

• American Fisheries Society. 1991. Investigation and Valuation of fish kills. American 

Fisheries Society Special Publication 24. 

Anderson, J.J. 1988. Diverting Migrating Fish Past Turbines. Northeast Environmental 

Journal 4: 109-128. (as cited by Kynard 1993). 

Clark, D.E. 1981. The Wedgewire Screen: A Part of the Sullivan Plant Downstream 

Migrant Bypass System. Manuscript. Portland General Electric Company. Portland, 

Oregon. 

Clark, D. E. and D.P. Cramer. 1993. Evaluation of the Downstream Migrant Bypass 

System- T.W. Sullivan Plant, Willamette Falls. Portland General Electric Company. 

Portland, Oregon. 

Consumers Power Company (CPC). 1985. 1985 Report of Deterrent Net Performance, 

J.R. Whiting Plant. Presented to the Michigan Water Resources Commission. 

CPC and the Detroit Edison Company. 1992. Ludington Pumped Storage Project; 1990 

Annual Report of Barrier Net Operation. Submitted to FERC December 29, 1992. 

Derr, J.A., H.E. Zich, R.F. Carline, and L.M. Young. 1993. Sampling Protocol for 

Estimating Entrainment and Turbine Mortality of Fish at Hydropower Sites. Prepared by 

PA State Univ. Statistical Consulting Center for USFWS. Coop. Agreement No. 14-

16-0009-1548 Work Order: 41. 

Energy & Environmental Management, Inc. 1992. Millville Hydro Station. FERC 

Project No. 2343. License Articles 405 & 406. 1991 Fish Entrainment Studies and 

Economic Worth of Lost Fishery. Prepared for the Potomac Edison Company and the 

Allegheny Power Service Corporation West Virginia. 

Environmental Resource Associates, Inc. 1984. Lake Erie Barrier Net, A Feasibility 

Study. Technical Report 61 Report to Cleveland Electric Illuminating Co. 

Electric Power Research Institute (EPRI). 1986. Assessment of Downstream Migrant 

Fish Protection Technologies for Hydroelectric Application. Prepared by Stone & 

Webster Engineering Corporation. EPRI Report 2694-1. 

EPRI. 1992a. Evaluation of the Eicher Screen at Elwha Dam: 1990 and 1991 Test 

Results. Prepared by Stone & Webster Engineering Corporation. EPRI TR-101704. 

EPRI. 1992b. Fish Entrainment and Turbine Mortality Review and Guidelines. 

Prepared by Stone & Webster Engineering Corporation. EPRI TR-101231. 

Fish Entrainment at Hydropower Projects Page 6-1 
EPRI. 1992c. Evaluation of Strobe Lights for Fish Diversion at the York Haven 

Hydroelectric Project. Prepared by Stone & Webster Engineering Corporation. EPRI 

TR-101703. 

EPRI. 1994a. Biological Evaluation of a Modular Inclined Screen for Oiverting Fish at 

Water Intakes. Prepared by Stone & Webster Engineering Corporation. EPRI TR104121. 

EPRI. 1994b. Research Update on Fish Protection Technologies for Water Intakes. 

Prepared by Stone & Webster Engineering Corporation. BPRI TR-104122. 

Eugene Water and Electric Board (EWEB). 1993. Design infonnation and test data 

from the Leaburg screening facility. Transmitted to Stone & Webster Engineering 

Corporation. 

Francfort, J.E., G.F. Cada, D.D. Dauble, R.T. Hunt, D.W. Jones, B.N. Rinehart, G.L. 

Sommers, and R.J. Costello. 1994. Environmental Mitigation at Hydroelectric Projects. 

Vol. IT. Benefits and Costs of Fish Passage and Protection. Prepared for the U.S. Dept. 

of Energy. 

Georgia Pacific Co:rporation. 1988. Downstream Passage of Atlantic Salmon Smolts and 

Kelts at Weldon Dam. Mattaceunk Project FERC No. 2520. 

Harza Engineering Company and RMC Environmental Services. 1992. Response of 

Atlantic Salmon Smolts to Louvers in the Holyoke Canal, Spring 1992. Prepared for 

Northeast Utilities Service Company Berlin, Connecticut. 

Harza Engineering Company and RMC Environmental Services. 1993. Response of 

Juvenile Clupeids to Louvers in the Holyoke Canal, Fall 1992. Prepared for Northeast 

Utilities Service Company Berlin, Connecticut. 

Hosey and Associates and Fish Management Consultants. 1990. Evaluation of the 

Chandler, Columbia, Roza, and Easton Screening Facilities. Completion Report for the 

Bureau of Reclamation Yakima, Washington. 

Hydroacoustic Technology, Inc.(HTI). 1993. Using Hydroacoustics for Fisheries 

Assessments. Manual for 2-day short course. 

Johnson, G.E., J.R. Skalski, and D.J. Degan. 1994. Statistical precision of hydroacoustic 

sampling of fish entrainment at hydroelectric facilities. North American Journal of 

Fisheries Management. 14:323-333. 

Klinect, D.A., P.H. Loeffelman, and J.H. Van Hassel. 1992. A New Signal Development 

Process and Sound System for Diverting Fish from Water Intakes. American Power 

Conference. pp. 427-432. 

Page 6-2 Fish Entrainment at Hydropower Projects 
Kynard, G. 1993. Anadromous Fish Behavior Important for Fish Passage. In: 

Proceedings of the Workshop on Fish Passage at Hydroelectric Developments. (Eds.) 

U.P. Williams, D.A. Scruton, R.F. Goosney, C.F. Bourgeois, D.C. Orr, and C.P. 

Ruggles. Canada Technical Report of Fish and Agricultural Sciences, No. 1905. pp. 

95-105. 

Lawler, Matusky & Skelly Engineers (LMS). 1986. Research Coordination for Field 

Testing of Cooling Water Intake System. 1985 Annual Report to Electric Power 

Research Institute Research Project 2214-4. 

Loeffelman, P.H., D.A. Klinect, J.H. Van Hassel. 1991. Fish Protection at Water 

Intakes Using a New Signal Development Process and Sound System. Waterpower '91. 

pp. 354-365. 

Neitzel, D.A., T.J. Clune, and C.S. Abernethy. 1990. Evaluation of Rotary Drum 

Screens Used to Project Juvenile Salmonids in the Yakima River Basin. In: Proceedings 

of the International Symposium on Fishways '90. Gifu, Japan. 

Nettles, D.C., and S.P. Gloss. 1987. Migration of Landlocked Atlantic Salmon Smolts 

and Effectiveness of a Fish Bypass Structure at a Small-Scale Hydroelectric Facility. 

North American Journal of Fisheries Management. Vol. 7:562-568. 

Northeast Utilities Service Company (NUSCO). 1993. Annual Report on Anadromous 

Fish Passage Activities and Facilities; Merrimack River, Eastman Falls and Ayers Island 

Projects. Letter report to Lois Cashell, Federal Energy Regulatory Commission, dated 

February 26, 1993. 

Public Service Company of New Hampshire (PSNH). 1992. Downstream Migration of 

Atlantic Salmon Smolts at PSNH Hydroelectric Stations on the Merrimack and 

Pemigewasset Rivers 1989-1990. Final Project Report. 

Raemhild, G., B. Ransom, B. Ross, and M. Dimmitt. 1984. Hydroacoustic Assessment 

of Downstream Migrating Salmon and Steelhead at Rock Island Dam in 1983. Report to 

Chelan Co. PUD No. 1 Wenatchee, Washington. 

Ross, Q.E., D.J. Dunning, R. Thorne, J.K. Menezes, G.W. Tiller, and J.K. Watson. In 

Press. Response of Alewives to High Frequency Sound at a Power Plant Intake on Lake 

Ontario. Submitted to North American Journal of Fisheries Management. 

RMC Environmental Services, Incmporated. 1993. Evaluation of Mitigative Measures 

for Juvenile Blueback Herring at the Little Falls Hydroelectric Project. Prepared for 

Little Falls Hydroelectric Associates. 

Fish Entrainment at Hydropower Projects Page 6-3 
Sale, M.J., G.F. Cacla, L.H. Chang, S.W. Christensen, S.F. Railsback, J.E. Francfort, 

B.N. 

Rinehart, and G.L. Sommers. 1991. Environmental Mitigation at Hydroelectric Projects 

Vol. I. Current Practices for Instream Flow Needs, Dissolved Oxygen, and Fish 

Passage. Prepared for the U.S. Dept. of Energy. 

SAS. 1989. JMP Users Guide, Version 2 of JMP. SAS Institute Inc. Cary North 

Carolina. 

Smith, H. 1993. Puntledge Hydro Fish Screens: Eicher Screen. Presented at the 1993 

American Fisheries Society Symposium on Fish Passage Responsibility and Technology, 

September 1-2, 1993, Portland, Oregon. 

Stone & Webster Engineering Corporation. 1991. Evaluation of a Barrier Net for 

Preventing Turbine Passage at the Pine Hydroelectric Project. Prepared for Wisconsin 

Electric Power Company. 

Taft, E.P., S. A. Amaral, F. C. Winchell, and C.W. Sullivan. In Press. Biological 

Evaluation of a New Modular Fish Diversion Screen. To be presented and published in 

the AFS Bioengineering Symposium, September 1993. 

Thome, R.E. 1992. Acoustic Estimation of Fish Entrainment, Analysis of Sources of 

Error -With Special Reference to Wisconsin Entrainment Projects. Prepared for State of 

Wisconsin Department of Natural Resources by BioSonics, Inc. March 27, 1992. 

U.S. Fish and Wildlife Service (USFWS), Wisconsin Department of Natural Resources, 

and Michigan Department of Natural Resources. 1992. Joint Agency Fish 

Entrainment/Turbine Mortality Study Plan Guidelines. Vol. 2: Entrainment and Turbine 

Mortality Studies, Appendix ill: Fish Entrainment and Turbine Mortality Study Plan 

Guidelines. 

Vogel, D.A., K.R. Marine and J.G. Smith. 1990. A Summary of Upstream and 

Downstream Anadromous Salmonid Passage at Red Bluff Diversion Dam on the 

Sacramento River, California, U.S.A. In: Proceedings of the International Symposium 

on Fishways '90. Gifu, Japan. 

Weyerhaeuser Paper Co.(Weyerhaeuser), Consolidated Water Power Co., and Nekoosa 

Papers, Inc. 1993. Assessment of Effects of Entrainment and Turbine Mortality on Fish 

Populations at Selected Hydroelectric Projects on the Wisconsin River. 

Winchell, F., S. Amaral, N. Taft, and C. Sullivan. 1993. Biological Evaluation of a 

Modular Fish Screen. Waterpower '93. 

Page 6-4 Fish Entrainment at Hydropower Projects 
6.2 Entrainment Study Reports Included in the Database 

Barnes Williams Environmental Consultants, Inc. (BWEC). 1993. Fish Entrainment 

Monitoring Program. Lower Hydroelectric Project Flambeau River, Price County, 

Wisconsin. FERC Project No. 2421-004. Prepared for the Flambeau Paper Cmporation, 

Park Falls, Wisconsin. 

BWECo. 1993. Fish Entrainment Monitoring Program Upper. Hydroelectric Station 

Flambeau River, Price County, Wisconsin. FERC Project No. 2640-011. Prepared for 

the Flambeau Paper Corporation, Park Falls, Wisconsin. 

BWECo. 1993. Fish Entrainment Monitoring Program. Pixley Hydroelectric Project 

Flambeau River, Price County, Wisconsin. FERC Project No. 2395-004. Prepared for 

the Flambeau Paper Corporation, Park Falls, Wisconsin. 

Barnes Williams Environmental Services. 1993. Fish Entrainment Monitoring Program. 

Crowley Hydroelectric Station, Flambeau River, Price County, Wisconsin. FERC 

Project No. 2473. Prepared for the Flambeau Paper Corporation, Park Falls, 

Wisconsin. 

Barnes Williams Environmental Services. 1992. Fish Entrainment Monitoring Program. 

Balsam Row Hydroelectric Station, Shawano, Wisconsin. Prepared for Mead and Hunt 

Consulting Engineers, Madison, Wisconsin, on behalf of Wisconsin Power & Light Co. 

Barnes Williams Environmental Consultants, Inc. 1991. Fish Entrainment Monitoring 

Program. Lock and Dam 2 Hydroelectric Project. FERC Project No. 4306-008. 

Prepared for the City of Hastings, Minnesota. 

BioSonics, Inc., and Beak Consultants, Inc. 1991. Fish Entrainment Studies Using 

Hydroacoustics at Station 26 on the Genesee River. Prepared for Rochester Gas and 

Electric Corporation Rochester, New York. 

Bohr, J. 1990. Fish Entrainment and Mortality Studies at the French Landing 

Hydroelectric Project on the Huron River, Michigan. Prepared for STS Hydropower, 

Ltd. Lansing, Michigan. 

CH2M HILL and BioSonics. 1988. Fish Population and Entrainment Studies for the 

Vanceburg Hydroelectric Generating Station No. 1. Prepared for the City of Vanceburg, 

Kentucky. 

Dames and Moore (D&M). 1992. Final Report, Fish Entrainment Studies, 

Weyerhaueser Company, Rothschild Hydroelectric Project. Prepared for the 

Weyerhaeuser Company Rothschild, Wisconsin. 

Duke Power. 1991. Excerpt from the Saluda application for license to the FERC 

Provided by Duke Power to Stone & Webster Engineering Corporation. 

Fish Entrainment at Hydropower Projects Page 6-5 
Duke Power. 1991. Excerpt from the Holidays Bridge application for license to the 

FERC Provided by Duke Power to Stone & Webster Engineering Corporation. 

Duke Power. 1991. Excerpt from the Gaston Shoals application for license to the 

FERC Provided by Duke Power to Stone & Webster Engineering Corporation. 

Duke Power. 1991. Excerpt from the Ninety-Nine Islands application for license to the 

FERC Provided by Duke Power to Stone & Webster Engineering Corporation. 

Duke Power Company (Duke Power). 1992. Buzzard's Roost Hydroelectric Station. 

Response to Schedule B, Question 7, Fish Entrainment and Entrainment Mortality at 

Buzzard's Roost Hydroelectric Project, South Carolina. Duke Power Company, 

Charlotte, North Carolina. 

EA Engineering, Science, and Technology (EA). 1991. Studies of Fish Entrainment and 

St. Joseph River Fish Populations Near the Constantine Hydroelectric Project. FERC 

Project 10661. Prepared for Michigan Power Company, Indiana Michigan Power 

Company and American Electric Power Columbus, Ohio. 

EA. 1991. Studies of Fish Entrainment, Smolt Migration, and St. Joseph River Fish 

Populations Near The Buchanan Hydroelectric Project. FERC Project 2551. Prepared 

for the Indiana Michigan Power Company and American Electric Power Environmental 

and Technical Assessment Division Columbus, Ohio. 

Energy & Environmental Management, Inc. (EEM). 1993. Letter from John B. Cliff m, 

dated May 6, to Doug Hjorth (Stone & Webster) providing updated entrainment 

information for the Millville and Dam 4 projects. 

EEM. 1992. Millville Hydro Station. FERC Project No. 2343. License Articles 405 & 

406. 1991 Fish Entrainment Studies and Economic Worth of Lost Fishery. Prepared for 

the Potomac Edison Company and the Allegheny Power Service Corporation West 

Virginia. 

c, 

EEM. 1991. Millville Hydro Station. FERC Project No. 2343. License Articles 405 & 

406. 1990 Fish Entrainment Studies and Economic Worth of Lost Fishery. Prepared for 

the Potomac Edison Company and the Allegheny Power Service Corporation West 

Virginia. 

EEM. 1990. Millville Hydro Station. FERC Project No. 2343. License Articles 405 & 

406. 1989 Fish Entrainment Studies and 1988 & 1989 Economic Worth of Lost Fishery. 

Prepared for the Potomac Edison Company and the Allegheny Power Service 

Corporation West Virginia. 

Page 6-6 Fish Entrainment at Hydropower Projects 
EEM. 1986. Dam No.4 Hydro Station. Installation of Unit No. 3 1985 and 1986 Field 

Studies Report. Prepared for the Potomac Edison Company and the Allegheny Power 

Service Corporation West Virginia. 

Harza. 1993. Final Report on Fish Entrainment Studies at the Wisconsin River Division 

Hydroelectric Project. FERC Project No. 2590. Prepared for Consolidated Water Power 

Co. Wisconsin Rapids, Wisconsin. 

Harza. 1992. Park Mill Hydroelectric Station, (FERC No. 2744). Article 401 Fish 

Entrainment Study, April 1990-March 1991. Prepared for Scott Worldwide, Scott Paper 

Company Marinette, Wisconsin. 

Harza Engineering Company. 1992. Final Report on Fish Entrainment Studies at the 

Centralia Hydroelectric Project, FERC Project No. 2255. Prepared for BVMCA, 

Kansas City, MO and Nekoosa Papers Inc. Port Edwards, Wisconsin. 

Harza Engineering Company (Harza). 1991. Evaluation of Entrainment of Fish 

Through Turbines at Dam 1 and Dam 3. Prepared for the Mead Corporation, Escanaba 

River Hydroelectric Project Escanaba, Michigan. 

Hydroacoustic Technology, Inc. (HTI). 1992: Hydroacoustic and Netting 

Evaluations of Fish Entrainment and Mortality at Moores Park Dam during 1990 and 

1991. Prepared for Lansing Board of Water and Light Lansing, Michigan. 

H ydroacoustic Technology, Inc. 1991. H ydroacoustic Evaluation of Fish 

Entrainment at Tower and Kleber Dams, Final Report. Prepared for Wolverine Power 

Supply Cooperative Cadillac, Michigan. 

Kleinschmidt Associates (KS). 1992. Fish Entrainment Study, Final Report. 

Prepared for Beaver Falls Municipal Authority Beaver Falls, Pennsylvania. 

Kleinschmidt Associates, 1990. Final Report, Fish Entrainment Study. 

Prepared for Elkem Metals Company Pittsburgh, Pennsylvania. 

Lawler Matusky & Skelly Engineer (LMS). 1991. Fish Entrainment Monitoring 

Program Alcona Hydroelectric Project. Prepared for the Consumers Powers Company 

Jackson, Michigan. 

LMS. 1991. Fish Entrainment Monitoring Program Five Channels Hydroelectric 

Project. Prepared for the Consumers Powers Company Jackson, Michigan. 

LMS. 1991. Fish Entrainment Monitoring Program Mio Hydroelectric Project. 

Prepared for the Consumers Powers Company Jackson, Michigan. 

LMS. 1991. Fish Entrainment Monitoring Program Loud Hydroelectric Project. 

Prepared for the Consumers Powers Company Jackson, Michigan. 

Fish Entrainment at Hydropower Projects Page 6-7 
LMS. 1991. Fish Entrainment Monitoring Program Cooke Hydroelectric Project. 

Prepared for the Consumers Powers Company Jackson, Michigan. 

LMS. 1991. Fish Entrainment Monitoring Program Foote Hydroelectric Project. 

Prepared for the Consumers Powers Company Jackson, Michigan. 

LMS. 1991. Fish Entrainment Monitoring Program Croton Hydroelectric Project. 

Prepared for the Consumers Powers Company Jackson, Michigan. 

LMS. 1991. Fish Entrainment Monitoring Program Hardy Hydroelectric Project. 

Prepared for the Consumers Powers Company Jackson, Michigan. 

LMS. 1991. Fish Entrainment Monitoring Program Rogers Hydroelectric Project. 

Prepared for the Consumers Powers Company Jackson, Michigan. 

Normandeau Associates, Inc. (NAI). 1992. Final Study Results and Recommendations, 

Fish Entrainment Study, FERC Project No. 9988-001, Article 401, John P. King Mill 

Project, Augusta, Georgia. Prepared for Spartan Mills Augusta, Georgia. 

RMC Environmental Services, Inc. 1991. Prickett Hydroelectric Project Entrainment 

and Turbine Mortality Report. Prepared for Stone & Webster Michigan, Inc. 

Englewood, Colorado. 

R. W. Beck and Associates (RWBeck) and Dames & Moore. 1992. Application for 

Original License, Major Water Power Project Five Megawatts or Less for the Abbeville 

Hydroelectric Project FERC Docket No. UL 88-31. Prepared for the City of Abbeville, 

South Carolina. 

RMC Environmental Services, Inc. (RMC), and BioSonics, Inc. 1992. Final Report, 

Entrainment Studies at the Brule Hydroelectric Project, FERC #2431. Summary of 

Hydroacoustic Studies and Details of the Net Studies. Prepared for the Wisconsin 

Electric Power Company Milwaukee, Wisconsin. 

RMC Environmental Services, Inc. 1992. Final Report, Study Plan to Assess the Impact 

of Power Plant Operations on Fish Resources, Youghiogheny Hydroelectric Project. 

Prepared for D/R Hydro Company Monroeville, Pennsylvania. 

RMC Environmental Services, Inc. and BioSonics, Inc. 1992. Final Report Entrainment 

Studies at the White Rapids Hydroelectric Project FERC #2357. Summary of 

Hydroacoustic Studies and Details of Net System Studies. Prepared for the Wisconsin 

Electric Power Company Milwaukee, Wisconsin. 

U.P. Engineering and Architectural Associates, Inc. (UPE&AA). 1992. Thornapple 

Hydroelectric Facility, Fish Entrainment and Mortality Study, Final Report. Prepared 

for Northern States Power Company Eau Claire, Wisconsin. 

Page 6-8 Fish Entrainment at Hydropower Projects