Do not WEED. This document 

should be retained in the EPA 

Region 5 Library Collection. 
Ad 

DISCLAIMER 

This report has been reviewed by the Great Lakes National Program Office 

and the Enforcement Division, Region V, U.S. Environmental Protection Agency, 

and was approved for publication. Approval does not signify that the contents 

necessarily reflect the views and policies of the u.S. Environmental 

Protecti on Agency, nor does mention of trade names or commercial products 

constitute endorsement or recommendation for use. 

Printed in the United States of America 

A vailable from 

National Technical Information Service 

U. S. Department of Commerce 

5285 Port Royal Road 

Springfield, VA 22161 

NTIS price codes 

Printed copy: AD9 

Microfiche copy: AD1 
ARGONNE NATIONAL LABORATORY 

9700 South Cass Avenue 

Argonne, Illinois 60439 

AN ASSESSMENT OF THE IMPACTS OF WATER INTAKES 

ON ALEWIFE, RAINBOW SMELT, AND YELLOW PERCH POPULATIONS 

IN LAKE MICHIGAN 

by 

S. A. Spigarelli, A. J. Jensen, 

and M. M. Thommes 

Radiological and Environmental Research Division 

Interagency Agreement No. EPA-IAG-78-D-X0322 

Project Officer: Gary S. Milburn 

U. S. EPA Region V, Enforcement Division 

Interagency Agreement No. EPA-IAG-79-D-F0819 

Project Officer: Vacys J. Saulys U. S. EPA, Great Lakes National Program Office 

ANL/ES-109 

EPA-905/3-81-001 

March 1981 

U.S. Environmental Protection Atency 11. 

Region 5. Utlrary (Pl-12J) :;; 

77 West Jackson BouJevarcJ. 12th FlOor 

Chicago, Il 60604·3590 

U. S. Environmental Protection Agency Great Lakes National Program Office 

536 South Clark Street 

Chicago, Illinois 60605 
The facilities of Argonne National Laboratory are owned by the United States Government. Under the 

terms of a contract (W-31-109-Eng-38) among the U. S. Department of Energy, Argonne Universities 

Association and The University of Chicago, the University employs the staff and operates the Laboratory in 

accordance with policies and programs formulated, approved and reviewed by the Association. 

MEMBERS OF ARGONNE UNIVERSITIES ASSOCIATION 

The University of Arizona 

Carnegie-Mellon University 

The University of Kansas 

Kansas State University 

Loyola University of Chicago 

Marquette University 

The Ohio State University 

Ohio University 

Case Western Reserve University 

The University of Chicago 

University of Cincinnati The University of Michigan 

Michigan State University 

University of Minnesota 

University of Missouri 

Northwestern University 

University of Notre Dame 

The Pennsylvania State University 

Purdue University 

Saint Louis University 

Illinois Institute of Technology 

University of Illinois 

Southern Illinois University 

The University of Texas at Austin 

Indiana University Washington University 

The University of Iowa 

Iowa State University 

Wayne State University 

The University of Wisconsin-Madison 

~--------------NOTICE--------------~ 

This report was prepared as an account of work sponsored by 

an agency of the United States Government. Neither the United 

States Government or any agency thereof, nor any of their 

employees, make any warranty, express or implied, or assume 

any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, 

product, or process disclosed, or represent that its use would 

not infringe privately owned rights. Reference herein to any 

specific commercial product, process, or service by trade name, 

mark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring 

by the United States Government or any agency thereof. The 

views and opinions of authors expressed herein do not 

necessarily state or reflect those of the United States Government or any agency thereof. 

U,s. Environmental Protect1on Agency 
FOREWORD 

The U.S. Environmental Protection Agency was established to coordinate 

administration of the major Federal programs designed to protect the quality 

of our envi ronment. An important part of the Agency I s effort i nvol ves the 

search for information about environmental problems, management techniques, 

and new technologies to optimize use of the nationis land and water resources 

and minimize the threat pollution poses to the welfare of the American people. 

The Great Lakes National Program Office (GLNPO) of the United States 

Environmental Protection Agency, was established in Region V, Chicago to 

provi de a spec if; c focus on water qual i ty concerns of the Great Lakes. The 

Great Lakes National Program Office provides funding for studies to address 

Great Lakes specific environmental concerns and to help fulfull U.S. 

commitments under the U.S.-Canada Great Lakes Water Quality Agreement of 1978. 

Thi s report provi des an ana lysi s of fi sh loss data generated by the 

electric power generating industry. It is a pioneering effort to utilize 

water-body wide assessment techniques to address single industry impacts on 

specific natural resources. We hope that the information and data contained 

herein will help planners and managers of both the electric power generating 

industry and regulatory agencies make better decisions for carrying forward 

their responsibilities. 

Madonna F. McGrath 

Di rector 

Great Lakes National Program Office 

iii 
ABSTRACT 

A large volume of water is withdrawn from Lake Michigan for cooling and 

other industrial and municipal purposes. Potential ecological impacts of such 

withdrawals have caused concern. This stuqy estimates the impacts of 

entra i nment and impi ngement at water intakes on a 1 ewi fe, smelt, and yellow 

perch populations of Lake Michigan. Impingement and entrainment estimates 

were based on data collected by utilities for 316(b) demonstrations at 16 

power pl ants. Two conventi onal fi shery stock assessment model s, the surpl us 

production model and the dynamic pool model, were applied to assess the 

impacts. Fisheries data were applied to estimate the model parameters. 

Movements related to spawning and seasonal habitat selection cause high 

variation in impingement and entrainment over time and location. Impingement 

and entrainment rates were related to geographic location, intake type and 

position, and volume of water flow. Although the biomass impinged and numbers 

entrained are large, the proportions of the standing stocks impinged and the 

proporti ons of the eggs and 1 arvae entrained are small. The reducti ons in 

biomass assuming full flow at all intakes and our estimates of biomass in 1975 

are predicted by the models to be: 2.86% for alewife, 0.76% for smelt, and 

0.28% for yellow perch. 

iv 
TABLE OF CONTENTS 

LIST OF FIGURES • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 

LIST OF TABLES ............................................................................................................... .. 

ACKNOWL E DGEMENTS ............................................................................................................ .. 

SUMMARY .............................................................................................................................. .. 

INTRODUCTION • .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 

ACQUISITION AND DEVELOPMENT OF DATA BASE. 

Sampled Power Plants .. Unsampled Intakes ..•.. 

IMPINGEMENT ESTIMATES •....••••....•.•...•.•.... 

Alewife Impingement - Sampled Intakes •. 

Alewife Impingement Lakewide ..•..•••• 

Rainbow Smelt Impingement - Sampled Intakes •. 

Rainbow Smelt Impingement Lakewide .•.•••.. 

Yellow Perch Impingement Sampled Intakes. 

Yellow Perch Impingement Lakewide •.....•....•••..••....•••••••.•. 

ENTRAI NMENT ESTIMATES .•••..•.••.•..••.••.•.••.••..•.. 

Alewife Entrainment Sampled Intakes .• 

Alewife Entrainment Lakewide •.••..•. 

Rainbow Smelt Entrainment Sampled Intakes. 

Rainbow Smelt Entrainment Lakewide ••....•• 

Yellow Perch Entrainment Sampled Intakes. 

Yellow Perch Entrainment Lakewide ....••.. 

FACTORS AFFECTING IMPINGEMENT AND ENTRAINMENT ... Effects of Intake Type ••• 

A 1 ewi fe .................. .. 

Rainbow Smelt ••.. 

Yellow Perch .••..•...•..... 

Effects of Flow and Geographic Location .. 

DEVELOPMENT OF THE MATHEMATICAL MODELS. 

Surplus Production Model •.•••••••.. 

Dynamic Pool Model ............................................................................... .. 

ESTIMATION OF BIOLOGICAL AND FISHING PARAMETERS •.• 

Surplus Production Model 

Alewife •.•••. 

Ye 11 ow Perch. 

Sme 1 t ...................................................... . 

Dynamic Pool Model ••••.••••• 

Alewife .......... . Ye 11 ow Perch .. Sme 1 t ••••••••• .. .. . .. .. . . . . . .. . . . .. .. . . .. .. .. .. . . . . .. .. . 

v 

Page 

vrr 

x 

xiii 

xv 

1 

3 

3 

7 

9 

9 

11 

15 

17 

18 

18 

19 

19 

20 

22 

24 

25 

26 

27 

27 

27 

31 

40 

40 

44 

44 

51 

56 

56 

56 

57 

59 

61 

61 

62 

64 
ESTIMATION OF POWER PLANT-RELATED PARAMETERS. 

Surplus Production Model ....••.. 

Al ewife ..•.•.•. 

Ye 11 ow Perch. 

Smel t ... Dynamic Pool Model. 

Alewife. 

Yell ow Perch. 

Sme 1 t ...•.•.. 

SIMULATION OF IMPINGEMENT AND ENTRAINMENT 

Alewife ..•... 

Ye 11 ow Perch. 

Sme 1 t .•.•.•.. 

IMPACTS. 

DISCUSSION OF MODELING RESULTS •.•.•..•.•..•.•..•••••••••••••••••.•.•..• 

REFERENCES ••••••••.•.•••••••••••••••••.•••••••••••.•••••••••••••••••.•• 

GLOSSARY OF TERMS ••••••••••.•••.•••••••••••••••••••••••••••.••••••••••• 

APPENDIX A ......•.••••..•••.•••..•...•••...••••.•..•.•.....••.•.••.. 

Plots of Daily Impingement and Entrainment Densities at Sampled 

Power Plants 

APPENDIX B •.••••••.••••••.•.••.•..••••••••..••••.••••....•..•...••••. 

Estimates of Proportions Impinged and Entrained during 

1975 at Sampled Power Plants Based on Designed Water Flows Using 

the Surplus Production and Dynamic Pool Models and Calculated 

Coefficients of Impingement and Entrainment 

vi 

64 

64 

66 

66 

66 

67 

68 

68 

68 

69 

70 

75 

78 

81 

90 

93 

96 

162 
LIST OF FIGURES 

1. Map of Lake Michigan showing the locations of sampled power plants and statistical districts........................................... 6 

2. Mean annual densities of impinged alewife at each sampled intake 

(1975).............................................................. 28 

3. Mean annual dens i ti es of entra i ned alewife eggs at each sampled 

jntake (1975) ................................................ e...... 28 

4. Mean annual densities of entrained alewife larvae at each sampled 

intake (1975}....................................................... 30 

5. Mean annual densities of impinged smelt at each sampled intake 

( 1975) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

6. Mean annual densities of entrained smelt eggs at each sampled intake 

(1975) .............................................................. 34 

7. Mean annual densities of entrained smelt larvae at each sampled 

intake (1975} .................................................. ".... 34 

8. Mean annual densities of impinged yellow perch at each sampled 

intake (1975) ............. 0,0........................................ 42 

9. Mean annual densities of entrained yellow perch eggs at each sampled 

intake (1975}....................................................... 42 

10. Mean annual densities of entrained yellow perch larvae at each 

sampled intake (1975)............................................... 43 

11. Relationship between total number of alewife impinged and total flow 

(1975) ..................... 8 ......................................... 43 

12. Relationship between total number of alewife eggs entrained and 

total flow (1975).................................................... 45 

13. Relationship between total number of alewife larvae entrained and 

total flow (/1975)................................................... 45 

14. Rel ati onship between total number of smel t impi nged and total flow 

(1975) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 

15. Relationship between total number of smelt eggs entrained and total 

flow (1975)......................................................... 46 

16. Relationship between total number of smelt larvae entrained and 

.to ta 1 flow (1975).................................................... 47 

17. Relationship between total number of yellow perch impinged and total 

flow ( 197 5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. It • • • • • • • • • • • 47 

vii 
18. Observed yields and yields predicted by surplus production model for 

a 1 ew i f e i n La k e M i chi g an. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

19. Stock production curves for alewife in Lake Michigan at five 

?if!erent levels of water withdrawal considering only the impact of 

1 mpl ngement ........................................................ . 

20. Observed yields and yields predicted by surplus production model for 

yellow perch in Lake Michigan ................................•...... 

21. Observed yields and yields predicted by surplus production model for 

smelt in Lake Michigan ............................................. . 

22. Impingement impact of increased water withdrawal on biomass of 

alewife in Lake Michigan (1975) ..............................•...... 

23. Impingement impact of increased water withdrawal on maximum 

sustainable yield (MSY) of alewife in Lake Michigan (1975) .....•.... 

24. Entrainment impact of increased water withdrawal on biomass of 

alewife in Lake Michigan (1975) .................................... . 

25. Entrainment impact of increased water withdrawal on maximum 

sustainable yield (MSY) of alewife in Lake Michigan (1975) ...•...... 

26. Combined entrainment and impingement impact of increased water 

withdrawal on biomass of alewife in Lake Michigan (1975) .....••..... 

27. Combined entrainment and impingement impact of increased water 

withdrawal on maximum sustainable yield (MSY) of alewife in Lake 

Michigan (1975) .................................................... . 

28. Combined impingement and entrainment impact of increased water 

withdrawal on biomass of yellow perch in Lake Michigan ............. . 

29. Combined impingement and entrainment impact of increased water 

withdrawal on MSY of yellow perch in Lake Michigan .............•.... 

30. Impingement impact of increased water withdrawal on biomass of smelt 

in Lake Michigan (1975) ............................................ . 

31. Impingement impact of increased water withdrawal on maximum 

sustainable yield (MSY) of smelt in Lake Michigan (1975) ........... . 

32. Entrainment impact of increased water withdrawal on biomass of smelt 

in Lake Michigan (1975) •.............•.......•...................... 

33. Entrainment impact of increased water withdrawal on maximum 

sustainable yield (MSY) of smelt in Lake Michigan (1975) ...••..•..•• 

34. Combined entrainment and impingement impact of water withdrawal on 

biomass of smelt in Lake Michigan (1975} .............•...........•.. 

viii 

58 

58 

60 

61 

72 

72 

73 

73 

74 

74 

77 

77 

79 

79 

80 

80 

82 
35. Combined entrainment and impingement impact of water withdrawal on 

maximum sustainable yield (MSY) of smelt in Lake Michigan (1975).... 82 

36. Relation between estimate of population biomass and estimate of 

proportion of biomass standing stock impinged for yellow perch in 

Green Bay (1975).................................................... 85 

37. Observed and predicted yields for yellow perch in Green Bay (1960-

1977)................................................................ 85 

38. Combined entrainment and impingement impact of increased water 

withdrawal on biomass of yellow perch in Green Bay.................. 88 

39. Combined entrainment and impingement impact of increased water 

withdrawal on maximum sustainable yield (MSY) of yellow perch in 

Green Bay ........••.•..•...••.•.••••.•.... '. . . • . • . . . • • • . . . . • • • • . . . • . . 88 

ix 

- --- --------~--------- ----- ~~ 
LIST OF TABLES 

Summa ry Tab 1 e. • . • . • • • . • . . • . . . . . . . . . • • . . . . • . . . • . . . . . . . . . • . . . . . • . . . . .• xv iii 

1. Intake sampling and design characteristics of 16 sampled power 

plants on Lake Michigan............................................. 5 

2. Locations and design flows of unsampled water intakes on Lake 

Michi gan....................... ...... ............ ................... 8 

3. Estimated total number and biomass of alewife, rainbow smelt, and 

yellow perch impinged each month at all 16 sampled power plants 

(1975) .............................................................. 10 

4. Estimated total number and biomass of alewife, rainbow smel t, and 

yellow perch impinged annually at each of the sampled power plants 

on Lake Michigan (1975)............................................. 10 

5. Mean weights (g) of alewife impinged each month at 15 power plants 

on Lake Michigan (1974-1976)........................................ 12 

6. Estimated total numbers and biomass (kg) of alewife, smelt, and 

yellow perch impinged at sampled power plants, unsampled power 

plants and municipal/industrial intakes on Lake Michigan, assuming 

design flow operation (1975)........................................ 13 

7. Estimated total annual impingement of alewife at all water intakes 

within each statistical district on Lake Michigan (1975), assuming 

design flow operation at all intakes................................ 14 

8. Compari son of estimated maximum annual impi ngement and entrai nment 

values (1975) with observed annual values for Edgewater Power Plant 

(1975-1976), Inl and Steel (1976-1977), and U. S. Steel/Gary (1976-

1977) water intakes................................................. 14 

9. Mean weights (g) of smelt impinged each month at 15 power plants on 

Lake Michigan (1974-1976)........................................... 16 

10. Estimated total annual impi ngement of rai nbow smel t at all water 

intakes within each statistical district on Lake Michigan (1975), 

assuming design flow operation at all intakes....................... 17 

11. Estimated total annual impingement of yellow perch at all water 

intakes within each statistical district on Lake Michigan (1975), 

assuming design flow operation at all intakes....................... 19 

12. Estimated total numbers of alewife, rainbow smelt, and yellow perch 

eggs and larvae entrained each month during the sampling periods at 

all 15 sampled power plants; estimated annual totals by 

extrapolation to full year for each plant (1975).................... 21 

x 

"' , WP244 
13. Estimated total numbers of alewife, rainbow smelt, and yellow perch 

eggs and larvae entrained during the sampling periods at each of the 

15 sampled power plants; estimated annual totals by extrapolation to 

full year for each plant (1975)................ ...•..............•.. 21 

14. Estimated total numbers of alewife, rainbow smelt, and yellow perch 

eggs and larvae entrained at sampled power plants, unsampled power 

plants, and municipal/industrial intakes on Lake Michigan, assuming 

design flow operation (1975) ........................................ 23 

15. Estimated total annual entrainment of alewife eggs and larvae at all 

water intakes within each statistical district on Lake Michigan 

(1975) assuming design flow operation at all intakes ............... . 

16. Estimated total annual entrainment of rainbow smelt eggs and larvae 

at all water intakes within each statistical district on Lake 

Michigan (1975) assuming design flow operation at all intakes ......• 

17. Estimated total annual entrainment of yellow perch eggs and larvae 

at all water intakes within each statistical district on Lake 

Michigan (1975) assuming design flow operation at all intakes ••..... 

18. Statistical comparisons between lakewide monthly mean impingement 

densities of alewife, smelt, and yellow perch for intake locations 

and types .................................................... II •••••• 

19. Statistical comparisons between lakewide annual mean entrainment 

densities of each species-life stage for intake locations and types. 

20. Stati sti cal compari sons of the monthly mean densi ti es (number/lOOO 

m3) of impinged alewife between dissimilar and similar intakes that 

are "adjacent" to each other. Underlined densities are 

23 

25 

26 

29 

29 

significantly higher (a = 0.05)..................................... 32 

21. Statistical comparisons of the monthly mean densities (number/m3) of 

entrained alewife eggs between dissimilar and similar intakes that 

are "adjacent" to each other. Underlined densities are 

significantly higher (a = 0.05)..................................... 35 

22. Statistical comparisons of the monthly mean densities (number/m3) of 

entrained alewife larvae between dissimilar and similar intakes that 

are "adjacent" to each other. Underlined densities are 

significantly higher (a = 0.05)..................................... 36 

23. Statistical comparisons of the monthly mean densities (number/m3) of 

impinged smelt between dissimilar and similar intakes that are 

"adjacent" to each other. Underlined densities are significantly 

higher (a = 0.05).................................................... 37 

24. Statistical comparisons of the monthly mean densities (number/m3) of 

entrained smelt eggs between dissimilar and similar intakes that are 

"adjacent" to each other. Underlined densities are significantly 

higher (a = O.05) .................... G •••••••••••••••••••••• o....... 38 

xi 
25. Statistical comparisons of the monthly mean densities (number/m3 ) of 

entrained smelt larvae between dissimilar and similar intakes that 

are "adjacent" to each other. Underlined densities are 

significantly higher (a = 0.05)..................................... 39 

26. Statistical comparisons of the monthly mean densities (number/m3) of 

impinged yellow perch between dissimilar and similar intakes that 

are "adjacent" to each other. Underlined densities are 

significantly higher (a = 0.05)..................................... 41 

27. Total catch, pound net effort (number of lifts), and catch per unit 

of effort for alewife in Lake Michigan, 1960-1977................... 57 

28. Total catch, trap net effort (number of lifts), and catch per unit 

of effor for yellow perch in Lake Michigan, 1960-1977............... 57 

29. Total catch, pound net effort (number of lifts), and catch per unit 

of effort for smelt in Lake Michigan, 1960-1977..................... 59 

30. Growth of alewife in Lake Michigan.................................. 61 

31. Fecundity of alewife in Green Bay as a function of length........... 63 

32. Age structure of alewife in Lake Michigan........................... 63 

33. Estimates of alewife parameters for dynamic pool model.............. 63 

34. Standard length (mm) of yellow perch at the end of each year of life 63 

35. Age structure of yellow perch population in Lake Michigan at 

Ludi ngton. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 

36. Estimates of yellow perch parameters for dynamic pool model......... 64 

37. Estimates of smelt parameters for dynamic pool model................ 64 

38. Comparison of commercial alewife catch from district WM1 in Green 

Gay and observed impingement at Pulliam Power Plant during 1975..... 83 

39. Residual sums of squares for fit of surplus production model to 

alewife catch and effort data....................................... 83 

40. Total catch, trap net effort (number of lifts), and catch per unit 

of effort for yellow perch in Green Bay, 1960-1977.................. 86 

41. Power plant related parameters for impact of Pulliam Power Plant on 

yellow perch populations of Green Bay (surplus production model).... 86 

xii 

14M A- Qi. A ~ 
ACKNOWLEDGMENTS 

The authors wish to thank the following people for their contributions to 

this study and to the preparation of the report: 

Dr. Ishwar Murarka, Electric Power Research Institute, Palo Alto, California. 

Ms. Deborah Bodeau, Environmental Impact Studies Division, Argonne National 

Laboratory. 

Mr. Richard Freeman, Environmental Impact Studies Division, Argonne National 

Laboratory. 

Ms. Patricia Tyrolt, Radiological and Environmental Research Division, Argonne 

National Laboratory. 

Mr. Gary Milburn, Enforcement Division, Region V, U.S. Environmental 

Protection Agency, Chicago, Illinois. 

Mr. Vacys Sau1ys, Great Lakes National Program Office, Region V, U.S. 

Environmental Protection Agency, Chicago, Illinois. 

Mr. Howard Zar, Enforcement Division, Region V, U.S. Environmental Protection 

Agency, Chicago, Illinois. 

Dr. Richard Hatch, Great Lakes Fishery Laboratory, U.S. Fish and Wildlife 

Service, Ann Arbor, Michigan. 

Dr. LaRue Wells, Great Lakes Fi shery Laboratory, U. S. Fi sh and Wi 1 dl ife 

Service, Ann Arbor, Michigan. 

Dr. Edward Brown, Great Lakes Fi shery Laboratory, U. S. Fi sh and Wi 1 d1 ife 

Service, Ann Arbor, Michigan. 

xiii 
SUMMARY 

Two factors related to water intakes have indicated the potential for 

impacts on Lake Michigan fish populations: (1) the present annual water 

wi thdrawa 1 (capac i ty) equals ~260% of the total inshore (depth dO m) volume 

of Lake Michigan, and (2) very large numbers of fish are entrapped by water 

intakes. This study estimates the numbers (and biomass) of alewife, rainbow 

smel t, and yellow perch that were entrapped in 1975 by all water intakes on 

Lake Michigan and assesses the impacts of these losses on the three fish 

populations. 

Impingement and entrainment data collected by utilities preparing 316(b) 

demonstrations were assembled into a computer data base by Argonne National 

Laboratory. Based on the data coll ected between 1974 and 1976 at 16 power 

plant intakes, annual estimates were made of the losses of adults, eggs, and 

larvae at sampled and unsampled water intakes on Lake Michigan. 

Impingement and entrainment of the three species are highly variable 

processes in time and space, primarily because of population movements related 

to spawning and seasonal habitat selection. 

-In 1975 the lakewide impingement of alewife was ~1.5 million kilograms; 

about 70% of this total was taken at conventional power plant intakes. 

Based on'previous estimates of alewife standing crop biomass, water intakes 

impinged a maximum of 1.2% of the 1975 standing crop of alewife. Water 

intakes on the western shore of Lake Mi chi gan and canal intakes imp; nged 

the highest densities (number/unit flow) of alewife. 

-Lakewide smelt impingement in 1975 was ~14 thousand kilograms and 

represented a maximum of 0.1% of the standi n9 crop bi omass; about 90% of 

the lakewide smelt impingement occurred at conventional power plants. 

Water intakes on the western shore of Lake Mi chi gan imp; nged the hi ghest 

densities of smelt. 

-A total of ~9.5 thousand kilograms of yellow perch were impinged in 1975 at 

all water intakes; no estimates of standing crop biomass of yellow perch 

were available from external sources. Approximately 60% of the lakewide 

impi ngement of perch occurred at convent; onal power pl ants and 40% were 

impinged in Green Bay. 

-At least 50 billion alewife eggs and one billion alewife larvae were 

withdrawn in 1975 by all water intakes on Lake Michigan. The majority of 

al ewi fe eggs and 1 arvae were entrai ned on III i no; s, Indi ana, and 

southwestern Michigan shores. Based on the temporal patterns of 

entrainment, it appears that planktonic alewife young are transported by 

countercl ockwi se currents in the southern basi n of Lake Mi chigan and may 

"accumulate" in the southern end of the lake. 

-Lakewide entrainment of rainbow smelt eggs and larvae were estimated to be 

400 million and 50 million, respectively. As with alewife, smelt eggs and 

larvae seemed to be transported by inshore currents and subsequently 

entrained at "downstream" intakes, especially on the southern (eggs) and 

western (larvae) shores of the lake. Smelt eggs and larvae are vulnerable 

to entrainment for a longer time and by more water intakes than are alewife 

xv 
eggs and larvae, primarily because smelt have slower development times. 

-Al though yellow perch eggs and 1 arvae may have been entrai ned, they were 

not identified at most sampled intakes. The highest numbers were observed 

at water intakes on Green Bay and the southeastern shore of Lake 

Michigan. Approximately 40 million yellow perch eggs and 2 million yellow 

perch larvae were withdrawn in 1975 by all water intakes. 

Three factors apparently affected the impingement and entrainment of the 

three fish species at sampled water intakes: (I) geographic location; (2) 

intake type and location, and (3) water flow. Comparisons of mean densities 

(flow normalization) of each species-lifestage between all sampled intakes 

grouped by type, indicated that: 

-Canal and onshore intakes impinge more alewife/unit volume than do offshore 

open bay or offshore porous dike intakes. 

-Onshore intakes and offshore porous dikes entrai n more al ewi fe eggs/uni t 

volume, while offshore open bays entrain higher densities of alewife 

larvae. 

-Canal intakes impinge higher numbers of rainbow smelt/unit volume during 

the spawning season while offshore intakes impinge higher densities during 

other periods. 

-Offshore intakes entrain more smelt eggs and larvae/unit volume in general. 

-The very heterogeneous distribution of yellow perch tended to confound the 

comparisons between intake types; however, if Green Bay intakes are 

excluded, offshore open bay intakes seem to impinge high densities of 

yellow perch. Canal and offshore open bay intakes may be equally 

destructive of perch eggs and larvae. 

-An analysis of the relationships between numbers impinged/entrained and the 

flows at sampled intakes suggests that ~50% of the variability in 

impingement and entrainment of each species-life stage is attributable to 

flow, with the exception of alewife eggs where no relationship was found. 

Two mathematical models were applied to (1) describe the dynamics of the 

impacted fish populations, (2) estimate stock biomass and mortality associated 

with water withdrawal, and (3) simulate the impact of present and increased 

water withdrawals. A dynamic pool model and a surplus production model, both 

standard fishery model s, were appl ied to assess the fish stocks. Different 

types of data were applied to estimate the parameters of the two models: the 

surplus production model relies on catch and effort (commercial fishery) data, 

whereas the dynamic pool model relies on life history data. The results 

obtained using the different models were quite similar. 

-Estimates of standing stock biomass of alewife and rainbow smelt obtained 

from the models are higher than those obtained from direct sampling of the 

populations by the Fish and Wildlife Service, but the direct estimates are 

considered minimum values. Although the biomass estimates in this study 

could be in substantial error due to parameter assumptions used in the 

models, even large errors in estimation of biomass would not significantly 

xvi 
alter the conclusions about the impacts of water withdrawal. Standing crop 

biomass estimates are listed below in the summary table. 

-Al though the entrai nment and imp; ngement coeffi ci ents (rates) were low at 

most sampled intakes, the cumulative impact of total water withdrawal 

(lakewide) is approaching levels where there may be reason for concern. At 

total capacity flow for all water intakes, al ewife bi omass is reduced ~3% 

and yield to the fishery is reduced ~4%; smelt biomass is reduced ~0.8% and 

yield is reduced ",1%; yellow perch biomass is reduced ~0.3% and yield is 

reduced ",0.5%. The impacts on yield to the fishery are higher than the 

impacts on biomass. 

-The impact of impi ngement was found to be 1 arger than the impact of 

entrainment, but entrainment impact is more difficult to determine. The 

impacts of impingement can be assessed using methods that are identical to 

those applied for fishery assessment and the results appear to be reliable. 

-If the reductions in standing stock biomass and yield due to water 

withdrawal are evaluated as though no other stresses are placed on these 

fish populations, the impacts are sman. Alternatively, if the combined 

sources of mortality are considered (e.g., predation, fishing, and water 

withdrawal), and if the liberal stocking of salmonid fishes is taken into 

account, the mortality of alewife and smelt at water intakes could be 

viewed as a significant impact on populations that may already be stressed 

by predati on from stocked salmoni ds. Conversely, the water i ntake-rel ated 

losses of alewife and smelt biomass can be viewed as significant losses in 

the production of salmonid biomass in Lake Michigan. 

xvii 
SUMMARY TABLE 

Al ewi fe Rainbow Smelt Yell ow Perch 

Estimates for 1975 Lake Michigan Tota1 Lake Michigan Tota1 Lake Michigan Tota1 Green Bay 

Maximum impingement (kg) 2.10 x 106 1.86 X 104 1.31 X 104 5.00 X 103 

Maximum egg entrainment (number) 7.39 x 10 10 6.15 X 108 4.81 X 107 1. 20 X 107 

Maximum larval entrainment (number) 1.31 x 109 8.28 X 107 3.26 X 106 2.40 X 106 

Standing stock biomass {kg} 

x Surplus production model 2.06 x 10 8 2.53 X 107 1.07 X 107 5.21 X 106 

< 

...... Dynamic pool model 2.37 x 10 8 2.47 X 107 1.00 X 107 ...... U.S. Fish & Wildlife Service 1.22 x 10 8 1. 37 X 10 ...... 7 

Percent reduction in standing stock 

Impingement 2.45 0.46 

Entrainment 0.41 0.30 

Impingement + entrainment 2.86 0.76 0.28 0.61 

Maximum sustainable yield (kg) 3.00 x 107 2.50 X 106 7.42 X 105 3.50 X 105 

Percentage reduction in MSY 

Impingement 3.42 0.71 

Entrainment 0.56 0.46 

Impingement + entrainment 3.98 1.18 0.47 1.03 
INTRODUCTION 

As of 1975, the combined capacity for water withdrawal by all power 

plant, industrial, and municipal water intakes on Lake Michigan exceeded 1.2 x 

1013 gal (4.8 x 10 10 m3 ) per year; this volume represents ,..,260% of the total 

inshore water «10 m deep) of the lake. Based on our calculations, all power 

plant intakes (including Ludington Pump-Storage) have the capacity to withdraw 

4.2 x 1010 m3 per year (230% per year) while Ludington has a capacity of 2.1 x 

1010 m3 per year (115% per year). Al though many intakes are not operated 

continuously or at full capacity, it is safe .to assume that a volume equivalent to the entire inshore volume is withdrawn by water intakes in less than 6 

months. 

Aside from the considerations of consumptive water use, the withdrawal of 

such large volumes of inshore water could have biological/ecological impacts 

since the inshore waters of Lake Michigan serve as spawning areas, migratory 

routes, and habitats for many species of fish that have commercial, 

recreational, and trophic importance. Free-swimming adult fishes are subject 

to entrapment by water intakes, and subsequent impingement on traveling 

screens. Immature fish (ichthyoplankton) are subject to entrapment and subsequent entrainment into industrial, utility or municipal process streams. 

Despite efforts to develop intake structures that reduce fish impingement and 

entrainment, no reductions in intake-related fish mortalities have been 

affected in Lake Michigan, except for external modifications such as the 

behavioral barrier placed around the Zion intake. 

Numerous species of fish are entrapped by water intakes around Lake 

Mi chi gan and the popul ati ons of many of these fi shes have fl uctuated greatly 

in recent years. Numerous factors influence the dynamics of fish populations in Lake Michigan, not the least of which are (l) predation by piscivorous 

fishes (salmonids) and man; and (2) competition between species with similar 

niche requirements. It has been hypothesized that the added mortality of 

fishes at water intakes may constitute a significant stress on some 

populations, but little effort has been expended to test this hypothesis. 

CDM/Limnetics [1] conducted a study which estimated the losses of adults, 

larvae and eggs of every fish species entrapped at 17 power plant intakes on 

Lake Michigan. These estimates indicated that approximately 93% of the total 

number of fish impinged were alewife (Alosa pseudoharengus), ~5% were rainbow 

smelt (Osmerus mordax), and ~0.5% were yellow perch (Perca flavescens). The 

total biomass impinged of each species was estimated to be 0.06% of the alewife and 0.07% of the smelt standing crops in Lake Michigan in 1974; neither 

fractional mortality was considered to be stressful. 

The present study was deSigned to provide independent estimates of lakewide impingement and entrainment-related fish mortalities and an initial 

assessment of the effects of this additional mortality on the population dynamics of three economically important species: alewife, smelt, and 

perch. These spec; es were chosen for study because (1) each is important in 

the fisheries of Lake Michigan, (2) alewife and smelt are critical forage 

species for the huge numbers of salmonid fishes introduced into the lake, and 

(3) each species suffers large intake-related mortalities at some or all of 

the water intakes on Lake Michigan. 

The objectives of this study were to (1) collect extant data on fish 

1 
impingement and entrainment at sampled power plant intakes and estimate mortalities at all unsampled intakes, thereby developing a lakewide data base; 

(2) compare species-specific losses between intake types and locations on Lake 

Michigan; (3) compare the losses of each species with previous (1975) and 

present estimates of population standing crop biomass; and (4) simulate the 

effects of intake-related fish mortality on species' production, standing 

crop, and yield to the fishery. In all calculations, it was assumed that all 

entrapped adults, larvae and egg die, i.e., a worse case assessment. 

The impact of entrai nment and impi ngement cannot be assessed di rectly. 

To determine the proportion of a population that is impinged or entrained, the 

number or biomass of the impacted population must be known or estimated. 

Direct estimates of abundance are difficult and costly for large populations, 

so a mathematical model was applied to estimate fish abundances in Lake 

Mi chi gan usi ng commerci al catch and effort data. Mathemati cal model s al so 

were applied to simulate the impact on standing stocks and yields under existing and increased water withdrawals from Lake Michigan. 

Models applied for power plant assessment have not been of the same form 

as models applied for assessment of the impact of fishing on fish 

popul ati ons. Model s constructed by persons wi th engi neeri ng backgrounds are 

often linear compartment types that do not adequately represent the biology or 

have poorly defined biological variables that are difficult to estimate. The 

models most commonly used by biologists are of the Leslie-matrix type [2-6]. 

These models are useful for population projection and consider the population 

age structure; but application requires estimation of a large number of parameters that are difficult to estimate. Also, these models require specificati on of compensation mechani sms and thi s aspect has been controversi al [7]. 

Finally, this approach requires good estimates of mortality and growth for 

early life history stages. Swartzman, Deriso, and Cowan [8] have critically 

compared several models applied for power plant impact assessment. A major 

diffi cul ty for workers in envi ronmental impact assessment is that, typi ca lly, 

results are required at once and there is little time to gain experience with 

different methods. 

In fisheries studies three models have been developed for assessment of 

the impact of fishing. These models were developed between the late 1920's 

and early 1960's, a period of 30 years. Development of these models was slow 

and it was accompanied by the development of an understanding of the problems 

of parameter estimation and of how to work with less than a complete understanding of how fish populations compensate for fishing. The three models are 

usually termed the surplus production model, dynamic pool model, and spawnerrecruit model. 

Surplus production models relate the biomass and productivity of the 

stock directly to yield. These are the simplest to develop and apply, but 

many assumptions are necessary. Application to laboratory and wild fish 

populations indicates that this type of model is useful for estimation of 

popul ati on abundance and for determi ni ng the level at whi ch a popul ation is 

being exploited [9]. 

The dynamic pool model is now the most widely applied type for stock 

assessment. Thi s model combi nes data on growth, reproducti on, and mortal ity 

and is both flexible and easy to apply. Structurally, the dynamic pool model 

2 
is more readily understood than the surplus production model, and it can be 

expanded easily to include new information. Application of dynamic pool 

models requires a considerable amount of information on growth and age structure. 

Spawner-recruit models have been applied in power plant impact assessment 

studies [7], but they were developed for salmon populations exhibiting clear 

spawner-recruit relationships, where data for numbers of spawners and recruits 

are obtainable. For most species, estimates of numbers of spawners and 

recruits are difficult to obtain, and no clear relationship between the number 

of spawners and the number of recruits is detectable. 

In thi s study both the surpl us producti on model and the dynami c pool 

model are appl i ed to estimate the bi amass of the popul ati on, number of eggs 

produced, and number of 1 arvae produced. These estimates are appl i ed to 

determine the proportions of each population impinged and entrained, and then 

to estimate coefficients of entrainment and impingement. The models are 

applied to examine the impact on standing stock, biomass, and yield of fish 

populations due to present and increased rates of water withdrawal. 

The surplus production model and dynamic pool model apparently have not 

been applied for power plant assessment but several components of the dynamic pool model have been applied [10-13J. Application of fisheries models for the 

assessment of environmental impact takes advantage of the considerable experience gained through the assessment of the impact of fishing on fish popula- tions. Application of the surplus production model and dynamic pool model 

together for power plant assessment gi ves a degree of confi dence in the 

results that is not attained with application of either model alone. The two 

models are entirely different structurally and the data for parameter estimati on in the two model s are enti rely different. Close agreement between the 

results of the two simulations with different models would constitute 

"independent" corroboration of the assessment. 

For estimation of power plant-related model parameters, full design. 

volume flow has been assumed and numbers and biomass entrained or impinged 

have been extrapolated to design flow conditions. 

ACQUISITION AND DEVELOPMENT OF THE DATA BASE 

Sampled Power Plants 

This study relied exclusively on extant data provided by the various 

electric utilities that conducted 316(b) studies and by federal/state resource 

agencies. Fish impingement data initially were obtained for a study of 

impingement throughout the United States [14J; entrainment data were obtained 

subsequently and added to the data base. Since variations in daily flow rates 

are common, especially at coal-fired power plants that are operated in a 

peaking mode, we obtained daily average flow rates for each of the sampled 

plants during their respective periods of impingement and entrainment 

sampling. 

The impingement and entrainment data bases exist as permanent batch-onlyaccessible data sets. They reside within the large capacity pool of Itel 

3 
7330-12 storage disc drives shared by Argonne National Laboratory IS IBM 

370/195 and IBM 3033 computer systems. Stati sti ca 1 ana lyses were performed 

using the Statistical ,Analysis System (SAS 79.2B version) [15]. Graphical 

output was achieved by using an interface (SASMYPLT) [16] between the SAS 

package and the PLOTIN/MYPLOT [17] general purpose pl otti ng program. Thi s 

interface, developed by the Radiological and Environmental Research Division, 

results in the production of publishable quality graphics. 

Table 1 summarizes the design characteristics and sampling intervals for 

16 power plants and Figure 1 shows the locations of these plants on Lake 

Michigan. Unfortunately, neither the sampling schedules nor the methods were 

standardized among plants. Most plants were sampled for impingement during 

the major portion of 1975, except for Bailly, Michigan City, Campbell, 

Palisades, and Big Rock; only two plants (Zion and Cook) were sampled for two 

consecutive years, providing some temporal comparison. The most common 

schedul e was to coll ect an integrated sample (~24 hours) every fourth day; 

only one plant (Cook) was sampled daily for impingement. Entrainment sampling 

was initiated in 1975 at all but one plant (Big Rock) and continued for less 

than one year at all plants except Cook, Bailly, Campbell, and Big Rock where 

at least one full year of data were collected. Most plants were not sampled 

for entrainment from January through March. The most common schedules of 

entrainment sampling were every fourth day or once per week, and most plants 

were sampled in the intake stream. 

It is difficult to evaluate the effects of variable methods on the estimation of fish impingement or entrainment as reported by the utilities; we 

made no attempt to normal i ze data for these potential sources of vari ance. 

Murarka et al. [18] compared various impingement sampling deSigns and 

concluded that the stratified-systematic scheme is superior to the systematicrandom sampling scheme used by most of the utilities on Lake Michigan. 

Power pl ant data sets that spanned 1 ess than one full year were extrapolated to a full year by assuming a linear reduction from the last data entry 

to zero at the end of the year and/or 1 i near extrapol at; on from zero to the 

first data entry for the year. This procedure allowed the estimation of 

annual impingement and entrainment values for all sampled power plants. 

If samples were not collected daily (all plants except Cook), missing 

daily values were estimated (interpolated) by means of the following equation: 

where 

I

i

+5 = (Ai + SR;,j) x fi+s for s = 1,2, ... , j-i (j-i > 0) 

R •. 

, ,J 

Aj - A; 

= j for all j > i. - i 

Ai' A· = observed impingement/entrainment ratet for the ith, jth days. 

Ii+s ~ impingement/entrainment value for (i+~) h missing observation. 

fi+s = water intake flow rate for the (i+s)t missing observation. 

4 
Table 1. Intake sampling and design characteristics for 16 sampled power plants on Lake Michigan. 

Approx. Intake Maximum Flow Impingement Entrainment 

Pl ant (ID) MWe Design (m3/yr) Sampling Dates Schedule Sampling Dates Schedule Location 

Zion (1) 2100 OOBa 3.48 x 109 02/28/74-12/31/75 every 4th day 04/16/75-09/17/75 l/week discharge/intake 

D. C. Cook (2 ) 2200 OOB 3.27 x 109 02/01/75-12/30/76 daily 01/01/75-12/31/75 daily discharge 

Bailly (3) 615 PO 6.70 x lOs 11/07/75-11/10/76 every 4th day 11/07/75-11/10/76 every 4th day discharge/intake 

Michigan City (4) 715 CNL 5.97 x lOs 12/03/75-06/28/76 every 4th day N/Ac N/A N/A 

Pulliam (5) 390 CNL 7.75 x lOs 04/04/75-03/22/76 every 4th day 04/09/75-08/27/75 24 hrs/week discharge/intake 

Kewaunee (6) 525 OOB 8.22 )( lOs 04/01/75-03/17/76 every 4th day 04/01/75-12/15/75 l/week intake 

c..n Poi nt Beach (7) 1030 PD 1.53 x 109 03/04/75-02/28/76 every 4th day 04/18/75-10/31/75 every 4th day intake 

Port Washington (8) 400 CNL 1.09 )( 109 03/03/75-02/25/76 every 4th day 04/15/75-10/28/75 every 4th day intake 

Lakeside (9) 345 PD 8.73 x lOS 03/07/75-02/06/76 every 4th day OS/20/75-10/29/75 every 4th day intake 

Oak Creek (10) 1670 CNL 2.45 x 109 03/04/75-02/27/76 every 4th day 04/17/75-10/30/75 every 4th day intake 

Waukegen (11) 1100 CNL 1.43 x 109 05/12/75-04/28/76 every 4th day 04/16/75-09/03/75 l/week discharge/intake 

Statel ine (12) 960 PD 1.65 x 109 04/05/75-03/30/76 every 4th day 04/05/75-09/04/75 every 4th day discharge 

D. Mitchell (13) 415 PD 8.23 x 108 05/03/75-04/27/76 every 4th day 05/03/75-09/20/75 every 4th day di charge/i ntake 

J. H. Campbell (14) 645 CNL 5.97 x lOS Jan 74-Mar 75 24 hrs/week 01/29/75-03/24/76 24 hrs/week intake 

Palisades (15) 840 OOB 1.19 x 10sb Mar 74-Mar 75 24 hrs/week 03/27/75-02/03/76 24 hrs/week intake 

Big Rock (16) 75 PO 9.55 x 107 Feb 74-Mar 75 24 hrs/week 02/07/74-03/19/75 24 hrs/week intake 

a OOB = offshore open bay; PD = porous dike; CNL = canal. 

b All plants operate once-through except Palisades which utilizes cooling towers. 

C Entrainment information reported for Michigan City not useful for this analysis. 
PULLlAM-__ -1lJ 

PORT WASHINGTON WM-5 

I 

LAKE 

MICHIGAN 

I 

MM-7 

OAK CREEK 

----------i o----J. H. CAMPBELL 

ZION NUC-----y 

STATE LINE 

r----------- WM-6 I 

-----1 

III. 

I 

I 

I 

I 

I 

_-L I __ 

MM-8 

PALISADES NUC 

&----DONALD C. COOK NUC 

...or----MICHIGAN CITY 

DI!AN H. MITCHELL 

Fig. 1. Map of Lake Michigan showing locations of sampled power plants and 

statistical districts.[l] 

6 
This method provides a weighted linear interpolation between successive observations on impingement and entrainment variables. The impingement/entrainment 

processes are approximated by linear segments. 

Entrainment data for D. C. Cook were received in a reduced form where 

numbers of each fish group were reported as totals for irregular time 

periods. These totals were divided by the number of days in the sample 

period, thereby producing average daily values for the period. No useful 

entrainment data were obtained from the Michigan City plant; therefore, 

Michigan City was treated as an unsampled plant for entrainment calculations. 

Observed, interpolated, and extrapolated daily values were summed by 

month and year for each sampled plant. For each of the three species, numbers 

and weights impinged, and number of eggs and larvae entrained were 

calculated. These totals were termed lIobservedll values even though missing 

dai 1y val ues were estimated by interpol ati on and extrapol ati on. Age cl asses 

or size distribution of impinged fishes were not reported for most power 

plants. Egg and larval categories were used for entrainment because no 

standard categories were reported by the various utilities. Some utility 

reports identified larval and IIjuvenilell stages; in these cases, both 

categories were considered to be larvae. 

Egg entrai nment data for D. C. Cook were reported as a total for the 

three species (i .e., no egg identification was made). Species totals were 

estimated assuming 90% of the total to be alewife eggs, 4% to be smelt eggs, 

and 1% to be perch eggs [19J. A similar problem was encountered with the 

Pull i am egg entrainment data except egg di ameters were reported. In thi s 

case, we estimated the fracti onal speci es total by assumi ng ranges in egg 

diameters for each species during the time periods that each would be expected 

to spawn (e.g., smelt eggs = 0.6-1.3 mm, April-May; alewife eggs = 0.6-1.3 mm, 

June-July; yellow perch = 1.6-2.3 mm, May-June). 

Us; ng the lIobservedll dai ly data for each sampl ed pl ant, we generated the 

data base which estimates the monthly and annual total s by fi sh category and 

by plant for the sampling periods, based on actual flows. An "extrapolatedll 

data base was generated whi ch estimates the maximum impi ngement/entrai nment 

losses as if all plants had operated at maximum (capacity) cooling water flow 

rate over the full year. These extrapolations were based on the ratios of 

actual/design flows. 

Unsampled Intakes 

Since the impingement/entrainment data base only represents fish losses 

at 16 of the 22 power plants on Lake Michigan and does not include estimates 

for other water intakes sited on the 1 ake, we developed ali st of all other 

intakes and their capacity flows (Table 2). Assuming capacity flow throughout 

the year, we estimated the annual impingement "and entrainment values for 

unsamp1ed intakes by multiplying the mean impingement and entrainment rates at 

all sampled plants in the same region (statistical district) by the capacity 

flows at unsampled intakes. 

Although we considered methods of estimation that would account for the 

influence of intake type and spatial heterogeneity in fish abundances, the 

extant information on unsampled intakes [20] is not very descriptive of design 

7 

.~~~.--.. - .. ---. 
Table 2. Locations and design flows of unsampled water intakes on Lake Michigan.[20] 

Plant Name 

Lake City Public Water Department 

Waukegan Water Utility 

Johns-Manville Products 

US Steel Works 

Johnson Outboards 

Abbott Laboratories 

City of North Chi cago 

Great Lakes Naval Station 

Ci ty of Lake Forest 

Fort Sheri dan-US Army DFAE 

Highwood Water Plant 

Highland Water Plant 

Village of Glencoe 

Mark Da1in M!moria1 Plant 

Village of Winnetka 

Kenni1worth Water Filtration Plant 

Wilmette Water Works 

Ci ty of Evanston Water and Sewer Dept City of Chicago Dept Water and Sewer 

John G Shedd Aquarium Hammond Water Dept 

Lever Bros Co 

Whiting Filtration Plant 

Ameri can- Ma i ze Prod Co 

American Oil Co-Whiting Refinery 

East Chicago Water Dept Inland Steel Co 

Youngstown Sheet and Tubing Gary-Hobart Water Corp 

Union Carbide-Linde Div 

Universal Atlas Cement 

US Steel 

Mi dwest Steel 

Bethlehem Steel-Burns Harbor 

Michigan City Dept of Water Works 

American Playground and Device Co 

Escanaba M.m Water Util ity-Sand Poi nt 

M!ad Paper Co 

Escanaba Generating Station 

Gladstone Water Treatment 

Gladstone Generating Station 

Ci ty of M!nomi nee Inland Lime and Stone Co 

Ci ty of Mi chi ana City of New Buffalo 

City of Bri dgman St Joseph Water Filtration Plant 

City of Benton Harbor Water Dept South Haven Water Treatment Plant 

Holland Water Treatment Plant 

Wyoming Water Treatment Plant 

Ci ty of Grand Rap; ds 

City of Grand Haven Water Treatment Plant 

MUskegon Hts Water Treatment Plant 

City of MUskegon Water Treatment Plant 

Ludington Water Filtration Plant 

Ludington Pump-Storage Facility 

Ci ty of Traverse Ci ty 

Baysi de Ci ty Li ght and Power Co 

M!dusa Portland Cement 

Penn-Dixie Cement Corp 

Marinette Water Works 

Green Bay Water Dept 

Two Rivers Water and Light Dept 

Manitowoc Public Utilities 

Manitowoc Power Plant 

Sheboygan Water Utility 

Edgewater Power Plant 

City of Glendale 

City of Pt Washington Filtration Plant 

City of Milwaukee 

North Shore Water Commission 

Univ of Wis-Mi1waukee-Centra1 Plant 

Cudahy Water Utility South Mi 1 waukee Water Uti 1 i ty 

Racine Water Dept Kenosha Water Utility 

Statistical 

Plant Type District 

8 

MUN 

UTI 

IND 

IND 

IND 

IND 

fotJN 

fotJN 

fotJN 

fotJN 

fotJN 

fotJN 

fotJN 

fotJN 

fotJN 

fotJN 

fotJN 

fotJN 

MUN 

fotJN 

fotJN 

IND 

fotJN 

IND 

IND 

fotJN 

IND 

IND 

fotJN 

IND 

IND 

IND 

IND 

IND 

MUN 

IND 

MUN 

IND 

UTI 

fotJN 

UTI 

fotJN 

IND 

fotJN 

fotJN 

MUN 

fotJN 

fotJN 

MUN 

fotJN 

MUN 

fotJN 

fotJN 

MUN 

fotJN 

fotJN 

UTI 

fotJN 

UTI 

IND 

IND 

fotJN 

fotJN 

fotJN 

fotJN 

UTI 

fotJN 

UTI 

fotJN 

fotJN 

MUN 

fotJN 

MUN 

fotJN 

fotJN 

fotJN 

fotJN 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

ILL 

IND 

IND 

IND 

IND 

IND 

IND 

IND 

IND 

IND 

IND 

IND 

IND 

IND 

IND 

IND 

MM1 

MMl. 

MMl. 

MMI. 

MI>[ 

MI>[ 

MI>[ 

Mt-2 

MMl 

Mt-fl 

Mt-fl 

Mt-fl 

Mt-fl 

Mt-fl 

MM7 

MM7 

MM7 

MM7 

MM7 

MM7 

Mt-fi 

Mt-fi 

MM4 

MM4 

MM3 

MM3 

WI>[ 

WMI. 

WM4 

WM4 

WM4 

Wf0f5 

Wf0f5 

Wf0f5 

Wf0f5 

Wf0f5 

Wf0f5 

Wf0f5 

Wf0f5 

Wf0f5 

Wt-fi 

Wt-fi 

Design Flow 

1,389 

6,944 

1,389 

2,244 

2,778 

11,111 

2,431 

4,167 

2,083 

521 

278 

5,729 

1,319 

2,222 

2,639 

311 

5,208 

16,667 

709,023 

139 

18,055 

3,819 

1,042 

9,028 

92,361 

11 ,805 

749,997 

318,748 

20,833 

69,120 

2,244 

568,669 

17,361 

305,000 

5,000 

449 

1,389 

20,833 

16,667 

1,500 

3,600 

1,181 

5,000 

494 

1,391 

404 

4,200 

4,167 

1,389 

4,444 

10,903 

24,305 

5,835 

294 

7,639 

2,082 

29,668,626 

3,472 

13,194 

1,795 

1,346 

1,389 

10,764 

4 

5,555 

13,465 

9,028 

131,956 

15,260 

4,167 

116,367 

4,028 

3,125 

4,514 

2,778 

15,833 

12,068 

5 

26 

5 

8 

11 

42 

9 

16 

8 

2 

1 

22 

5 

8 

10 

1 

20 

63 

2,684 

1 

68 

14 

4 

34 

350 

45 

2,839 

1,207 

79 

262 

8 

2,153 

66 

1,155 

19 

2 

5 

79 

63 

6 

14 

4 

19 

2 

5 

2 

16 

16 

5 

17 

41 

92 

22 

1 

29 

8 

112,309 

13 

50 

7 

5 

5 

41 

o 

21 

51 

34 

500 

58 

16 

441 

15 

12 

17 

11 

60 

46 
and the available data on fish abundances do not have the necessary spatial 

definition. Some sampling of adult fish and ichthyoplankton in inshore waters 

was performed at each power plant required to do 316(b) studies, but the 

methods and periods of sampling were not standardized between locations. 

Consequently, util i ty data on fi sh abundances coul d not be compared between 

intake sites and were not useful for adjusting impingement/entrainment rates, 

based on fish abundance. 

Lakewide estimates of impingement and entrainment-related mortalities of 

alewife, smelt, and yellow perch are reported as totals for (1) all power 

plant intakes excluding the Ludington Pump-Storage Power Plant; (2) all power 

plant intakes including Ludington; (3) all other intakes; and (4) all intakes 

on Lake Michigan. These results provide the only estimates of total intakerelated fish mortalities for Lake Michigan, albeit 6 years after the fact. 

IMPINGEMENT ESTIMATES 

Alewife Impingement - Sampled Intakes 

Impingement rates of alewife at the 16 sampled power plants were strongly 

dependent on time of year and location in Lake Michigan. Maximum impingement 

of alewife occurred from May through July, with the largest numbers (1.93 x 

107 ) and biomass (7.03 x 105 kg) impinged in May (Table 3). Approximately 95% 

(1.8 x 107 ) of the May 1975 impi ngement occurred at the Zi on pl ant and thi s 

inordinately high value was the direct result of a delay in the positioning of 

a behavioral barrier (screen) around the intake [1J; in 1974, the screen was 

in place in May and the numbers of alewife impinged that month at Zion was ~3.8 x 105 • It is evident that the high impingement rates in early summer 

reflect the inshore spawning migrations of adult alewife rather than seasonal 

changes in total cooling water flow. Likewise, the reductions in alewife 

impi ngement from December through March refl ect the offshore movement of the 

alewife population during early winter. A small peak in alewife impingement 

occurred in October and November prior to the winter migration offshore. 

The annual total alewife impingement at the sampled power plants was 

estimated to be 2.67 x 107 (9.17 X 105 kg). Almost 90% of this total was 

impinged at four of the 16 sampled power plants (Table 4): 69% at Zion (1.83 

x 107 ), 9% at Port Washington (2.41 x 106 ), 6% at Oak Creek (1. 70 X 106 ), and 

4% at Point Beach (1.19 x 106 ). Figures A.1.a-A.16.a (Appendix A) show the 

daily densities of alewife impinged at each sampled plant. The maximum daily densities were (10 alewife/1000 m3 at all plants except Zion and Port 

Washington where the maximum densities were 400 and 40 alewife/1000 m3 , 

respectively. Relatively high impingement densities ()0.1 alewife/lOOO m3 ) 

were sustained between April and November at five of the sampled plants: 

Zion, Waukegan, Port Washington, Point Beach, and Kewaunee. These plants have 

no common attributes other than their locations on the western shore of Lake 

Michigan. The combination of relatively high alewife densities and total 

flows resulted in the disporportionate impingement of alewife at a few plants 

on the western shore. The relatively low impingement densities at the plants 

sited on the eastern shore (Cook, Palisades, Campbell, and Big Rock) probably 

reflect a general trend toward lower alewife densities along this shore. 

The timing of the major influx of alewife (rapid increase in impingement) 

9 
Table 3. Estimated total number and biomass of alewife, rainbow smelt, and yellow perch 

impinged each month at all 16 sampled power plants (1975). 

Total Flow Al ewife Smelt Perch m3 Number Kg Number Kg Number Kg 

January 8.57 x 108 8.08 X 102 2.10 X 10 1 1. 34 X 10" 2.31 X 102 6.99 X 103 8.20 X 101 

February 7.39 x 108 4.82 X 102 1.20 X 10 1 1.18 X 10" 3.18 X 102 2.82 X 10 3 6.80 X 101 

March 7.88 x 108 2.47 X 10" 7.46 X 10 2 3.05 X 10" 1. 24 X 10 3 3.95 X 10 3 9.50 X 101 

April 9.01 x 108 6.08 X 10 5 2.53 X 104 1.41 X 10 5 2.13 X 10 3 5.55 X 10 3 3.56 X 102 

May 1. 02 x 109 1.93 X 107 7.03 X 10 5 4.61 X 10" 5.23 X 102 7.89 X 103 5.27 X 102 

June 9.93 x 108 3.83 X 10 6 1. 09 X 10 5 3.58 X 10" 4.88 X 10 2 1.89 X 103 1. 52 X 102 

July 1.16 x 109 1.69 X 10 6 4.48 X 104 1.22 X 10 5 1. 24 X 10 3 2.60 X 103 2.70 X 102 

August 1.18 x 109 4.75 X 105 1.40 X 104 9.03 X 10" 7.33 X 10 2 1.83 X 103 1. 52 X 102 

September 1.05 x 109 1.06 X 10 5 3.00 X 10 3 6.91 X 10" 4.46 X 10 2 2.03 X 103 8.80 X 10 1 

October 1.09 x 109 1. 77 X 105 3.74 X 10 3 1.23 X 10 5 6.96 X 102 6.26 X 10" 6.27 X 102 

November 9.63 x 108 1.94 X 10 5 1. 92 X 10 3 4.61 X 10" 5.42 X 102 2.79 X 10" 4.62 X 102 

December 9.62 x 108 2.15 X 10" 3.86 X 102 3.48 X 10" 1.05 X 10 3 1. 05 X 10" 1. 53 X 102 

Total 

observed 1.17 x 1010 2.65 X 107 9.07 X 10 5 7.64 X 10 5 9.63 X 10 3 1. 37 x 105 3.03 X 103 

Estimated 

annual 

total 2.67 x 10 7 9.17 X 105 7.69 X 10 5 9.77 x 10 3 1. 39 X 105 3.11 X 103 

Table 4. Estimated total number and biomass of alewife, rainbow smelt, and yellow perch impinged annually at each of the sampled power plants on Lake Michigan (1975). 

Total Flow Alewife Smelt Perch m3 Number Kg Number Kg Number Kg 

Zion 2.04 x 109 1.83 X 107 6.80 X 105 5.80 X 10" 2.48 X 103 5.85 X 102 6.90 X 101 Cook 1.32 x 109 1. 73 X 105 5.11 X 103 4.11 X 103 5.10 X 101 1.28 X 10" 3.97 X 102 

Bailly 4.71 x 108 1.21 X 105 4.52 X 103 7.54 X 102 1. 70 X 101 6.66 X 102 4.40 X 101 Mi chi gan City 1.01 x 108 1.03 X 105 N/A 3.23 x 102 N/A 2.89 x 102 N/A Pull iam 3.34 x 108 5.78 X 105 2.46 X 104 7.30 X 103 2.73 X 102 1.18 X 105 2.14 X 103 

Kewaunee 6.70 x 108 1.79 X 105 4.84 X 103 1.91 X 10" 4.75 X 102 2.40 X 102 4.00 X 101 

Point Beach 1.21 x 109 1.19 X 106 3.74 X 104 1. 76 X 105 1. 26 X 103 2.55 X 102 3.90 X 101 

Port Washington 5.74 x 108 2.41 X 106 6.11 X 10" 7.79 X 10" 8.95 X 102 2.62 X 102 2.30 X 101 

Lakeside 2.64 x lOB 4.79 X 10" 1.40 X 103 1.19 X 102 2.00 x 100 1.80 x 101 3.00 x 100 

Oak Creek 1.64 x 109 1. 70 X 106 3.29 X 10" 4.09 X 105 3.76 X 103 1.43 X 103 1.06 X 102 

Waukegan 9.32 x 108 7.66 X 105 2.80 X 10" 9.81 X 103 3.77 X 102 3.21 X 102 3.80 X 101 

Stateline 1.02 x 109 6.57 X 105 2.19 X 10" 8.55 X 102 2.30 X 101 1.24 X 103 8.20 X 101 

Mi tchell 5.11 x 108 1.46 X 105 3.68 X 103 3.25 X 102 4.00 x 100 5.16 X 102 4.60 X 101 

Campbell 4.17 x 108 4.54 X 10" 1.10 X 103 5.39 X 102 1.07 X 101 3.42 X 102 7.14 x 100 

Palisades 1.22 x 108 3.14 X 102 1.22 X 101 1.40 X 101 2.27 X 10-1 1.10 X 101 1.13 X 10-1 

Big Rock 8.20 x 107 9.50 X 101 3.51 x 100 1.28 X 102 2.38 x 100 1.70 X 101 2.04 x 100 

Total observed 1.17 x 1010 2.65 X 107 9.07 X 105 7.64 X 105 9.63 X 103 1.37 X 105 3.03 X 103 

Estimated annual 

total 2.67 x 107 9.17 X 105 7.69 X 105 9.77 X 103 1. 39 X 105 3.11 X 103 

10 

Ln 
in the spring was highly dependent on latitudinal location. Plants on the 

southern basin of the lake experienced initial high impingement densities in 

March or April while those on the northern basin experienced alewife influxes 

during late April and May. This appare'nt locational effect on the timing of 

inshore mi grati ons is undoubtedly 1 inked to the different inshore warmi ng 

rates between north and south locations. The Pulliam plant was somewhat 

unique in that no alewife were impinged until mid-May, indicating a complete 

absence of alewife from southern Green Bay between January and Apri 1, and a 

massive influx in May. 

Although most plants impinged very few alewife during the winter months, 

relatively high and sustained densities of alewife were impinged during winter 

at Port Washington, Waukegan, and Zion and less frequently at other plants. 

Only the Pulliam, Lakeside, Oak Creek, and Big Rock plants did not impinge 

alewife during mid-winter. Impingement totals during winter months (Table 3) 

were relatively low compared with other seasons but the indication of periodic 

inshore movements or continued inshore residence by alewife duri ng wi nter is 

rather enigmatic. Table 5 summarizes the mean weights of alewife impinged 

each month and year at the sampl ed pl ants. The mean wei ghts of al ewife 

impi nged duri ng wi nter months were often greater than duri ng other months, 

indicating that the largest/oldest alewife either (1) tend to precede the 

general population in the spring spawning migration, or (2) that some larger 

alewife tend to remain/migrate inshore during the winter. The mean weights of 

alewife impinged during and after the major spawning runs tended to decrease 

with time (May through November), indicating a size-related timing to the 

spawning migration or to inshore distributions of alewife. This relationship 

may be a function of size-related temperature preferences [21] and the natural 

temperature cycle of inshore waters. 

Secondary peaks in alewife impingement occurred in the fall at about half 

of the sampled plants (Figs. A.l.a-A.16.a), with no apparent effect of location on the occurrence of this fall peak. Beginning in September 1974, 

October 1975, and September 1976 (Table 5) the lakewide mean weights of 

impinged alewife decreased markedly and remained low for 2-3 months each year, 

reflecting the predominance of very small alewife (5-10 g), presumably young 

of the year (yay). Most plants that experienced fall peaks in alewife 

impingement showed concurrent decreases in mean weights of alewife, implying 

offshore to inshore movements by yay alewife at that time and location. 

Lakeside (Fig. A.9.a) and Zion (Fig. A.1.a) impinged substantial numbers of 

alewife in the fall of 1975, but showed minimal decreases in me,an weights of 

impinged fish; however, Zion experienced a major influx of yay alewife in the 

fall of 1974. 

Al though the evi dence in Table 5 is equi voca 1, the 1 akewi de average 

weights of alewife may have increased between 1974 and 1976. Zion data indicate an increase between 1974 and 1975, while Cook data indicate a decrease 

between 1975 and 1976. The annual mean weights 'of alewife impinged at each 

plant tended to range between 24 and 37 g, while those at Pulliam (42.5 g) and 

Oak Creek (19.3 g) apparently were extreme values. 

Alewife Impingement - Lakewide 

Based on the observed impingement rates at the 16 sampled power plants, 

the maximum annual lakewide impingement of alewife at all water intakes was 

11 

~~ ~--------------
Table 5. Mean weights (g) of alewife impinged each month at 15 power plants on Lake Michigan, 1974-1976. Dashes indicate sampling but 

no alewife impinged. 

Annual Mean 

Pl ant (IO) Year Jan Feb Mlr Apr Mly Jun Jul Aug Sept Oct Nov Dec Weights 

Zion (l) 1974 41.2 40.5 39.5 35.3 28.7 28.8 22.9 23.1 14.8 29.3 31.6 

1975 16.2 46.1 54.6 44.7 37.0 32.8 27.9 28.9 21.1 18.1 31.3 32.5 37.1 

Cook (2) 1975 5.4 30.2 37.6 34.9 24.9 24.8 24.5 18.0 5.2 23.1 41.4 29.6 

1976 50.9 36.7 43.4 40.8 30.1 24.7 25.4 22.7 6.7 5.2 25.1 26.1 26.2 

Bailly (3) 1975 11.0 23.8 } 37.4 

1976 32.4 13.9 56.5 43.4 43.8 35.9 31.5 25.1 15.5 6.3 24.1 

Pulliam (5) 1975 38.6 43.7 49.7 40.2 39.4 24.7 2.7 16.2 42.5 

1976 

Kewaunee (6) 1975 27.0 29.5 32.0 31.4 28.7 28.9 23.4 12.3 - } 27.6 

1976 45.0 72.0 62.0 

Poi nt Beach (7) 1975 36.6 32.2 33.9 34.6 33.3 23.8 6.1 5.3 32.1 31.4 

1976 33.1 34.0 

Port Washington (8) 1975 28.2 40.5 24.9 27.2 21.4 31.2 18.4 6.5 20.7 21.4 } 25.3 I-' 1976 20.5 20.3 N Lakeside (9) 1975 3.5 23.9 28.6 38.4 28.9 32.0 23.3 20.5 27.0 29.3 

1976 

Oak Creek (l0) 1975 36.8 31.7 28.1 19.1 13.0 19.3 13.4 14.9 18.4 18.6 19.3 

1976 

Waukegan (11) 1975 31.8 23.2 17.1 30.1 19.2 7.6 8.3 2.7 } 26.5 

1976 37.2 53.3 48.9 35.3 

State Li ne (12) 1975 41.6 37.1 29.1 24.6 16.6 37.6 22.4 12.6 41.8 } 33.6 

1976 30.1 

Mitchell (13) 1975 39.1 26.9 26.1 30.0 17.9 6.6 2.1 12.0 } 25.6 

1976 105.7 23.0 30.7 

Campbell (14 ) 1974 22.7 37.4 37.4 27.8 26.1 15.2 8.2 6.4 6.4 7.4 24.1 

1975 

Palisades (l5) 1974 46.7 43.7 30.0 38.1 35.2 29.3 39.0 

1975 32.4 

Bi g Rock (l6) 1974 35.6 35.7 41.3 37.8 37.0 

1975 

I: Mean Wei ghts 1974 36.9 40.5 35.6 34.2 32.8 27.8 15.6 14.8 10.6 18.4 26.7 

n Plants 1975 16.2 39.3 37.5 32.9 32.5 29.2 28.1 28.3 24.5 14.4 14.0 24.2 26.8 

1976 44.4 36.2 52.7 37.6 37.0 30.3 28.5 23.9 11.1 5.8 24.6 26.1 29.9 
estimated to be 6.18 x 107 (2.10 X 106 kg}(Table 6). Since this estimate is 

based on the assumption that all intakes were operated continuously at maximum 

capacity, it is an over-estimate of the annual lakewide impingement. The 

total observed flow at the 16 sampled power plants in 1975 (1.17 x 1010 m3 ) 

was ~58% of capacity flow (2.03 x 1010 m3 ) and probably is representative of 

annual water usage by all conventional power plants. Other intakes on Lake 

Michigan probably are operated at or near capacity flows. It follows that the 

actual 1akewide impingement of alewife in 1975 was on the order of 1.5 x 106 

kg. Approximately 70% of the annual total a1 ewi fe impi ngement occurred at 

conventional power plants, despite the fact only 43% of the total flow was 

used by these power p1 ants. The reasons for thi s anomaly are: (1) Zi on IS 

inordinate impingement rate in 1975 and (2) the relatively low estimated 

density of alewife in the region of the Ludington Pump Storage Plant. 

Table 6. Estimated total numbers and biomass (kg) of alewife, smelt, and yellow perch impinged at sampled power 

plants, unsampled power plants, and municipal/industrial intakes on Lake Michigan, assuming design flow operation (1975). 

Total Flow Alewife Smelt Perch 

(m3 ) Numoer Kg Numoer Kg f:Jumoer Kg . 

16 sampled power plants 2.03 x 1010 4.53 X 107 1.55 X 106 1.18 X 10 6 1. 55 X 104 3.13 X 105 6.70 X 103 

Unsampled power plants 3.70 x 108 8.80 X 105 2.35 X 104 2.77 X 104 3.21 X 102 1.13 X 102 1.14 X 101 

Total conventational plants 2.07 x 1010 4.62 X 107 1. 57 X 106 1.21 X 10 6 1. 58 X 104 3.13 X 105 6.71 X 103 

Ludington P.S. plant 2.11 x 10 10 2.53 X 106 7.50 X 104 6.03 X 104 7.56 X 102 1.88 X 105 5.81 X 103 

Total all power plants 4.18 x 1010 4.87 X 107 1.65 X 10 6 1.27 X 106 1. 66 X 104 5.01 X 105 1.25 X 104 

Total municipal/industrial 6.51 x 109 1.31 X 107 4.56 X 10 5 8.53 X 104 2.07 X 103 1.60 X 104 6.20 X 102 

Total all intakes 4.83 x 10 10 6.18 X 107 2.10 X 106 1.36 x 10 6 1.86 X 104 5.17 X 105 1.31 X 104 

The total annual impingement of alewife in each statistical district is 

given in Table 7. The mean densities of impinged alewife were highest in 

Illinois> WM5 > WM1; all of these regions are on the western side of the 

lake. The highest total volumes of water are withdrawn in districts MM6 > 

Indiana > Illinois > MM8 although the highest numbers were impinged in 

Illinois> WM5 > Indiana. Thus, no clear relationship exists between total 

flow and estimated total alewife impingement in statistical districts. 

The estimates given in Table 7 should be interpreted and used with 

caution. In statistical districts where no sampling was performed (e.g., 

MM4), the observed density from an adjacent district (MM3) was applied to 

calculate the numbers impinged (i .e., assumed density x flow = estimated 

number). In the case of unsamp1ed intakes within districts where some 

sampling was performed, the estimates seem to be reasonable. Table 8 presents 

a comparison of our estimates for three intakes that were classified as 

unsamp1ed (i.e., the data were not included in our data base), but actually 

were sampled. In two cases (Edgewater and Inland Steel) we overestimated the 

observed values and in the case of U.S. Steel/Gary our estimate was less than 

observed. 

Recent estimates of the alewife standing crop in Lake Michigan placed the 

minimum total biomass at approximately 122-123 x 106 kg during 1974 and 1975 

[24] and 56.5 x 106 [24] to 73.8 x 106 kg [25] in 1976. The assumption of a 

13 
total of 1. 5 x 106 kg of al ewi fe impi nged at all water ; ntakes in 1975 

indicates that a maximum of 1.2% of the standing crop was lost due to impingement. The reported 54% decrease in biomass between 1975 and 1976 [24] is 

similar to the trend observed in impingement density at the Cook plant, i.e., 

a mean impingement density of 0.1319 alewife/1000 m3 in 1975 and 0.0912 

alewife/IOOO m3 in 1976 [19]. 

Table 7. Estimated total annual impingement of alewife at all water 

intakes within each statistical district on Lake Michigan (1975). 

assuming design flow operation at all intakes. 

District Total Flow Density Number Kg (m3 ) (N/m3) 

WMI. 7.99 x 108 1. 73 X 10-3 1.38 X 106 5.87 x 10" 

WM2 0 0 0 0 

WM3 0 0 0 0 

WM4 2.39 x 109 7.30 x 10-" 1. 75 X 106 5.39 x 10" 

Wt-!i 2.55 x 109 2.94 X 10- 3 7.48 X 106 1. 90 X 105 

Wr-fi 2.51 X 109 1.03 X 10-3 2.59 X 106 5.01 x 10" 

III i noi s 6.46 x 109 6.44 X 10-3 4.16 X 107 1.54 X 106 

Indiana 8.10 x 109 4.88 x 10-" 3.96 X 106 1.16 X 105 

Mf.f3 3.42 x 109 1.20 x 10-" 4.10 X 105 1.22 x 10" 

MM7 7.03 x 108 1.20 x 10-" 7.78 x 10" 1. 95 X 103 

Mr-fi 2.11 x 10 10 1.20 x 10-" 2.53 X 106 7.50 x 10" 

MMS 0 0 0 0 

MM4 3.32 x 107 1.16 X 10-6 3.80 X 10 1 1.00 x 100 

MM3 1.02 x 108 1.16 X 10-6 1.18 X 102 4.00 x 100 

MM2 9.95 x 106 1.16 X 10-6 1.20 X 10 1 4.00 X 10- 1 

MMI. 9.08 x 107 1.16 X 10-6 1.05 X 102 4.00 x 100 

Total all 

intakes 4.83 x 1010 6.18 X 107 2.10 X 106 

Table 8. Comparison of estimated maximum annual impingement and eer~ainment values (1975) 

with 0~~2~ved annual values for Edgewr~§~ Power Plant (1975-1976). Inland Steel (1976-

1977). and U.S. Steel/Gary (1977) water intakes. 

Edgewater Power Plant Inl and Steel U.S. Steel/Gary AN[ Est. Obs. Afi)[ Est. Obs. AtJL Est. OEis. 

Alewife 7.7 X 105 5.2 X 105 7.3 X 105 1.2 X 105 5.5 X 105 7.4 X 105 

Rainbow smelt 2.4 x 10" 1.8 X 103 1.6 X 103 5.6 X 103 1.2 X 103 6.4 x 10" 

Yell ow perch 88 N/A 1.9 x 103 3.9 X 102 1.5 X 103 >860 

Alewife 

eggs 2.5 x 106 3.0 X 107 7.7 X 109 1.8 X 108 5.9 X 109 N/A 

larvae 4.4 x 105 1.8 x 10" 6.3 X 107 2.3 X 107 4.7 X 107 N/A 

Rainbow smelt 

eggs 5.7 x 10" 0 9.9 X 106 3.0 X 107 7.5 X 106 N/A 

larvae 1.0 x 105 3.9 X 105 2.8 X 106 3.4 X 1.06 2.1 X 106 N/A 

Yellow perch 

eggs 0 N/A 3.0 x 10" N/A 2.3 x 10" N/A 

1 arvae 3.0 x 103 N/A 3.4 x 10" N/A 2.6 x 10" N/A 

Limnetics [1] reported an estimated total of 2.08 x 106 lbs (9.41 x 105 

kg) of alewife impinged at 17 power plant intakes on Lake Michigan and 

14 
concl uded that thi s bi omass represents ~O .064% of the standi ng crop bi omass, 

as reported by Edsall et al. [26J. Our estimate of alewife impingement at 16 

plants (9.17 x 105 kg) is nearly identical to that reported by Limnetics, but 

more recent estimates [24J of the 1975 standing crop biomass indicate that the 

sampled power plants impinged a maximum of 0.75% of the total alewife biomass. 

Rainbow Smelt Impingement - Sampled Intakes 

In some ways, the impingement rates of smelt were dependent on time and 

location in a fashion similar to the impingement of alewife. A peak in smelt 

impingement occurred in April, presumably during the spawning period, but 

nearly equal peaks al so occurred in July and October at the sampl ed intakes 

(Table 3). The numerical peak in October probably reflects the inshore aggregation of YOY smelt, as indicated by the relatively small increase in total 

weight impinged that month. The peak in July may have been related to 

hydrological conditions (e.g., upwelling) or some unknown interaction between 

smelt and other species, such as alewife. Although smelt impingement 

decreased during winter months, the decreases were not as pronounced as those 

observed for alewife. 

The annual total smelt impingement at the sampled intakes was estimated 

to be 7.69 x 105 (9.77 X 103 kg) in 1975. Four plants on the western shore of 

Lake Mi chi gan accounted for approximately 94% of the total observed smel t 

impingement (Table 4): i.e., 53% at Oak Creek (4.09 x 105 ), 23% at Point 

Beach (1.76 x 105 ), 10% at Port Washington (7.79 x 104 ), and 8% at Zion (5.80 

x 104 ). In general, proportionately fewer smelt were impinged at intakes on 

the southern and eastern shores of the lakes (Figs. A.l.b-A.16.b). Maximum 

daily impingement densities were on the order of <5 smelt/IOOO m3 at Pulliam, 

Point Beach, and Oak Creek; at other plants the maximum densities were 

generally (1 smelt/1000 m3 • 

Relatively little or no smelt impingement occurred during winter months 

at 6 of the sampled plants: Pulliam, Lakeside, Mitchell, Campbell, Palisades, 

and Big Rock. Evidence of major influxes of smelt during the spawning period 

was not as clear cut as that observed with alewife. Apparent spawning peaks 

in impingement were evident at Zion, Waukegan, Oak Creek, Stateline, Cook, and 

Campbell during March and April; and at Michigan City, Bailly, Lakeside, 

Pulliam, and Big Rock during April and May. Thus, no apparent locational 

effect was observed for the timing of the major spring impingement of smelt. 

The mean weights of smelt impinged each month at each sampled intake are 

given in Table 9. The highest monthly mean weights (30-50 g) occurred either 

in winter or spring at most plants, and often coincided with the initiation of 

spring peaks in impingement. After spring maxima, mean weights tended to 

decrease with time and, beginning in July, YOY smelt apparently predominated 

the impingement, as evidenced by mean weight ranges between 3 and 10 g for 1 

to 5 months in the late summer and fall. The monthly averages indicate a 

lakewide predominance of YOY smelt during August and September 1974 and 1975, 

and in October 1976. Al though Zi on and Cook data suggest increases in mean 

smelt weights between 1974 and 1976, lakewide means indicate a decrease in 

mean weight of smelt over this period. Conversely, the lakewide mean weights 

of impinged alewife may have increased slightly between 1974 and 1976 (Table 

5). Considering the extensive sampling that is represented in these data, it 

15 
Table 9. Mean weights (g) of smelt impinged each month at 15 power plants on Lake Michigan, 1974-1976. Dashes indicate 

sampling but no smelt impinged. 

Annual Mean 

Plant (10) Year Jan Feb Mir Apr Miy Jun Jul Aug Sept Oct Nov Dec Weights 

Zion (1) 1974 31.1 32.4 27.3 24.8 24.0 15.6 12.7 47.9 43.1 52.2 28.9 

1975 38.4 62.9 50.3 32.9 11.2 19.5 21.0 32.1 37.7 58.2 50.6 

Cook (2) 1975 18.5 9.0 20.5 16.7 11.1 10.2 4.3 5.0 1.5 7.2 10.7 12.6 

1976 10.6 23.6 14.4 28.4 8.6 9.2 12.2 19.6 12.9 5.2 13.3 13.0 14.1 

Bailly (3) 1975 14.6 

1976 21.6 3.9 30.9 42.3 11.9 7.2 3.4 2.8 22.2 

Pulliam (5) 1975 37.6 25.9 20.5 37.7 40.0 37.4 

1976 

Kewaunee (6) 1975 18.1 17.1 18.0 20.0 20.1 20.0 25.4 24.7 28.6 24.7 

1976 28.3 34.0 37.9 

Poi nt Beach (7) 1975 24.9 43.8 30.2 26.9 32.6 5.3 4.9 4.7 6.3 8.5 7.2 

1976 5.4 17.1 

Port Washington (8) 1975 26.8 33.4 26.8 21.4 6.4 5.4 7.9 21.5 24.5 24.8 11.5 I-' 1976 22.8 25.5 0"'1 Lakeside (9) 1975 28.6 11.9 12.5 14.3 18.2 

1976 19.5 18.4 

Oak Creek (10) 1975 28.8 7.1 8.8 10.3 7.8 8.9 4.~ 14.6 11.2 16.1 9.2 

1976 23.2 19.4 

Waukegan (11) 1975 17 .5 10.2 4.7 6.9 8.0 13.2 20.0 47.9 22.0 

1976 27.0 34.3 22.6 26.8 

State Line (12) 1975 26.2 31.5 19.1 13.6 6.0 4.7 61.8 6.0 26.9 

1976 30.5 34.3 35.5 

Hi tchell (13) 1975 28.7 15.3 5.7 6.5 9.1 7.3 4.8 8.4 12.0 

1976 22.7 33.7 23.8 40.7 

Campbell (14) 1974 26.7 19.5 34.9 7.5 28.3 20.0 

1975 28.3 

Palisades (15) 1974 35.3 35.3 

1975 

Big Rock (16) 1974 16.6 19.7 18.6 

1975 

1: Mean Wei ghts 1974 31.1 27.8 22.2 29.9 24.0 15.6 12.7 47.9 25.3 40.3 27.7 n Plants 1975 38.4 62.9 28.0 27.5 23.2 16.0 13.3 9.2 10.2 15.9 21.3 24.0 24.2 

1976 21.2 24.4 27.5 34.6 10.3 8.2 7.8 11.2 12.9 5.2 13.3 13.0 15.8 
appears that mean weights of alewife and smelt vary as the inverse of each 

other. 

Rainbow Smelt Impingement - Lakewide 

Assuming design (capacity) flow at all water intakes on Lake Michigan, we 

estimated the maximum 1 akewi de impi ngement of smel t to be 1.36 x 106 (1.86 X 

104 kg) (Tabl e 6). Accounti ng for the 1 ess than capacity flows at power 

plants, we conclude that at least 1 x 106 (1.4 X 104 kg) smelt were impinged 

at all intakes in 1975. Recent studies of smelt annual standing crop in Lake 

Michigan estimated the minimum smelt biomass to be 13.7 x 106 kg in 1975 and 

11.1 x 106 kg in 1976 [27]. Assumi ng 1. 4 x 104 kg to have been impi nged at 

all intakes in 1975 and a stock of 13.7 x 106 kg, we conclude that a maximum 

of 0.10% of the biomass was lost due to impingement. Limnetics [1] estimated 

that 17 power plants impinged 9.17 x 103 kg of smelt in 1975, which amounted 

to 0.06% of the estimated 1974 standing crop biomass; our estimate of 9.77 x 

103 kg for 16 power pl ants represents 0.07% of the estimated 1975 standing 

crop. Approximately 90% of the total annual impingement of smelt occurs at 

conventional power plants, despite the fact that only 43% of the total flow 

during the sampling period was used by these plants. The relatively low 

densities of smelt on the southern and eastern shores of Lake Michigan 

probably result in low numbers impinged despite large volumes of water withdrawn by the Ludi ngton Pumped Storage Power Pl ant and muni ci pa 1 Ii ndustri a 1 

intakes in those regions. 

Table 10. Estimated total annual impingement of rainbow smelt at all 

water intakes within each statistical district on Lake Michigan (1975), 

assuming design flow operation at all intakes. 

Di strict Total Flow Density Number Kg (m3) (N/m3) 

WMI. 7.99 x 108 2.18 X 10-5 1. 75 X 104 6.53 X 102 

WM2 0 0 0 0 

WM3 0 0 0 0 

WM4 2.39 x 109 1.04 X 10-4 2.49 X 105 2.22 X 103 

Wf16 2.55 x 109 9.31 X 10-5 2.37 X 105 2.73 X 103 

WfvIi 2.51 x 109 2.49 x 10-4 6.24 X 105 5.73 X 103 

Illinois 6.46 x 109 2.28 x 10-5 1.48 x 105 6.23 X 103 

Indiana 8.10 x 109 1.07 x 10-6 8.69 X 103 1.67 X 102 

M/oB 3.42 x 109 2.86 X 10-6 9.77 X 103 1.22 X 102 

MM7 7.03 x 108 2.86 X 10-6 1.08 X 103 1.90 X 101 

MfvIi 2.11 X 1010 2.86 x 10-6 6.03 x 10'+ 7.56 X 102 

Mf16 0 0 0 0 

MM4 3.32 x 107 1.56 X 10-6 5.20 X 101 1.00 x 100 

MM3 1.02 x 108 1.56 X 10-6 1.59 X 102 3.00 x 100 

MM2 9.95 x 106 1.56 X 10-6 1.55 X 10 1 3.00 X 10-1 

MMI. 9.08 x 107 1.56 x 10-6 1.42 X 102 3.00 x 100 

Total all 

intakes 4.83 x 1010 1. 35 X 106 1.86 x 10'+ 

The estimated total annual impingement of smelt in each statistical 

district is given in Table 10. The mean annual densities of impinged smelt 

(calculated as the average of all daily observations at sampled intakes within 

a district) were highest in WM6 > WM4 > WM5 > Illinois> WMl, indicating the 

relatively high abundance of smelt on the western shore of the lake. The 

apparent spatial differences in smelt distribution negate the possibility of 

17 
establishing a clear relationship between volume of water withdrawn (flow) and 

impingement of smelt among statistical districts. For the same reasons given 

in the discussion of alewife data, the estimates of total smelt impingement in 

each statistical district should be interpreted with caution. In the case of 

districts with sampling results, the estimates are expected to be approximately correct. Table 8 presents a comparison of our estimates for three intakes 

that were sampled, but were not included in the observed data base. Two of 

the estimates (Inland Steel and U.S. Steel/Gary) were lower than reported by 

the industries, while that for the Edgewater plant was an order of magnitude 

higher than reported by Limnetics [1]. 

The reported standing crop biomass of smelt decreased ~19% between 1975 

and 1976 [27]. A comparison of the mean annual impingement densities at the 

Cook plant between 1975 (0.0029/1000 m3 ) and 1976 (0.0017/1000 m3 ) indicates a 

decrease of ~40% in smelt abundance over this period. 

Yellow Perch Impingement - Sampled Intakes 

Numbers of yellow perch impinged at the 16 sampled intakes were greatest 

in the late fall-early winter (Table 3). Total biomass of impinged perch was 

highest in October, followed by May and November. A spawning-related peak of 

adults was impinged in May while larger numbers of other age classes were 

impi nged in the 1 ate fall months. Lowest numbers and bi omass of impi nged 

perch occurred in the August-September and January-March periods of 1975. 

The annual total perch impingement at the sampled intakes was estimated 

to be 1.39 x 105 (3.11 X 103 kg) in 1975. Eighty-five percent of the total 

bi omass and 95% of the total number of impi nged perch were taken by three 

power plants (Table 4); i.e., 85% of the total number at Pulliam (1.18 x 105 ); 

9% at Cook (1. 28 X 104 ); and 1% at Oak Creek (1. 43 X 10 3 ). In general, few 

perch were impinged at most plants, except for those mentioned above. Maximum ~aily impingement densities were on the order of ,3 perch/1000 m3 at Pulliam 

between October-December and ,1 perch/1000 m3 at Cook between OctoberNovember. At all other plants, the maximum densities were <0.1 perch/1000 m3 

(Figs. A.1.c-A.16.c). Winter densities of impinged perch were not consistently low and indicate substantial inshore densities in winter in some areas of 

the lake; i.e., in the southern basin and isolated areas such as Green Bay 

(Pulliam) and Pigeon Lake (Campbell). 

Yellow Perch Impingement - Lakewide 

Assuming capacity flow at all water intakes on Lake Michigan, we 

estimated the maximum lakewide impingement of yellow perch to be 5.17 x 105 

(1.31 X 104 kg}(Table 6). Accounting for the less than capacity flows at 

power plants, we conclude that at least 3.5 x 105 (9.5 X 103 kg) yellow perch 

were impinged in 1975. To date, no estimates are available for the standing 

crop biomass of yellow perch in Lake Michigan. 

Approximately 60% of total annual impingement of yellow perch occurs at 

conventional power plants, while only 43% of the total flow during the 

sampling period was used by these plants. Based on the assumption that inshore yellow perch densities are similar between the Cook and Ludington areas, 

we estimate that the Ludington plant withdrew 1.88 x 105 yellow perch in 

1975. Thi s val ue represents approximately 36% of the estimated lakew; de 

18 
total. 

The estimated annual impi ngement of yell ow perch in each stati sti cal 

district is given in Table 11. The mean annual densities of impinged yellow 

perch (average of all daily observations at sampled intakes within a district) 

were highest in WM1 followed by MM8 and Indiana, indicating the relatively 

high abundance of perch in Green Bay and the southeastern areas of Lake 

Michigan. The values in Tables 6 and 11 should be interpreted with caution, 

since critical assumptions were made about the relative densities of yellow 

perch in unsampled districts. However, a comparison of estimated yellow perch 

impingement with observed values at intakes that were classified as unsampled (no data included in data base) shows very good agreements in districts where 

sampling data were included in the data base (Table 8). 

Table 11. Estimated total annual impingement of yellow perch at all 

water intakes within each statistical district on lake Michigan (1975), 

assuming design flow operation at all intakes. 

District Total Flow Density Number Kg (m3) (N/m3) 

Wf.U. 7.99 x 108 3.52 x 10-" 2.81 X 105 5.11 X 103 

W~ 0 0 0 0 

WM3 0 0 0 0 

WM4 2.39 x 109 2.64 X 10-7 6.31 X 102 1.01 X 102 

WMS 2.55 x 109 3.34 X 10-7 8.51 X 102 7.90 X 101 

Wf.fi 2.51 x 109 8.67 X 10-7 2.17 X 103 1.61 X 102 

Illinois 6.46 x 109 3.05 X 10-7 1.97 X 103 2.32 X 102 

Indiana 8.10 x 109 1.29 X 10-6 1.04 x 10" 6.64 X 102 

MI-fl 3.42 x 109 8.91 X 10-6 3.05 x 10" 9.41 X 102 

MM7 7.03 X 108 8.91 X 10-6 1.44 X 103 4.00 X 101 

Mf.fi 2.11 x 1010 8.91 X 10-6 1.88 X 105 5.81 X 103 

MMS 0 0 0 0 

MM4 3.32 x 107 2.07 X 10-7 7.00 x 100 1.00 x 10° 

MM3 1.02 x 108 2.07 X 10-7 2.10 X 101 3.00 x 10° M~ 9.95 X 106 2.07 X 10-7 2.00 x 100 2.00 X 10-1 

Mf.U. 9.08 x 107 2.07 X 10-7 1.90 X 10 1 2.00 x 100 

Total all 

intakes 4.83 x 1010 5.17 X 105 1.31 x 10" 

ENTRAINMENT ESTIMATES 

Alewife Entrainment - Sampled Intakes 

The major periods of entrainment were May through August for alewife eggs 

and June through September for alewife larvae (Table 12). Peaks in total 

entrai nment at the sampled pl ants occurred in June for both al ewife eggs and 

larvae. Each month, the numbers of entrained larvae were one to two orders of 

magni tude lower than the numbers of entrained eggs. No eggs were entrained 

during the period October through March. No larvae were entrained during the 

months January through April. An estimated total of 1.11 x 1010 eggs and 2.01 

x 108 larvae were entrained at the 15 sampled intakes in 1975. The sampling 

periods probably were adequate to estimate the entrainment of alewife eggs, 

but may have been inadequate at some intakes to characterize the late summerfall entrainment of alewife larvae. Therefore, the annual estimate of 

19 

--~----------.--------~. 
entrained larvae is almost twice that observed. 

Figures A.1.d-A.16.d show the time-dependent nature of alewife egg 

entrainment and indicate peak densities ~100 eggs/m3 at Bailly, Waukegan, and 

Mitchell. Extremely low peak densities (.;;0.01 eggs/m3) were observed at the 

Campbell, Palisades, and Big Rock plants. Despite substantial impingements of 

alewife at Point Beach, Port Washington, Lakeside, and Oak Creek, the reported 

densities of entrained alewife eggs were uniformly low at these plants (.;;0.3 

m3). This anomaly is difficult to explain in view of the fact that sampled 

plants to the north (e.g., Kewaunee) and south (e.g., Zion) of this group of 

plants showed substantially higher densities of entrained alewife eggs. 

The initiation of alewife egg entrainment occurred 1-2 months after the 

initial large impingements of adults at all but one plant. At Pulliam, the 

initiation of alewife impingement lagged behind that at other plants (late May 

rather than April-May) and egg entrainment commenced almost immediately thereafter. The typical lag period between initial high impingement densities and 

egg entrainment indicates that early migrants (inshore occupants) are not 

completely gravid and become so while occupying warmer inshore waters in the 

spring. Peak larval densities (Figs. A.1.e-A.16.e) occurred 1-2 months after 

peak egg densi ti es at most sampl ed intakes on the western shore of the 1 ake 

(except Lakeside, Zion, and Waukegan) while on the southern and southeastern 

shores, the egg and larval peaks were much less separated in time. This 

apparent spatial difference may be the result of (I) accelerated growth rates 

of immature alewife in the warmer southern basin and/or (2) a net countercl ockwi se movement of inshore currents and i chthyopl ankton in the southern 

basin of Lake Michigan. Peak densities of alewife larvae were ~1 larvae/m3 at 

Cook and Bailly, and ~0.1/m3 at Zion, Waukegan, and Mitchell. 

The estimated total numbers of alewife eggs and larvae entrained at each 

of the sampled intakes are given in Table 13. Intakes on the southern shore 

of Lake Michigan accounted for the majority of alewife eggs and larvae 

entrained by the sampled intakes. Bailly, Waukegan, Mitchell, Stateline, 

Cook, and Zion combined accounted for 96% of the total alewife eggs and 97% of 

the total alewife larvae entrained by the sampled intakes during 1975. Since 

the intakes on the western shore of the lake impinged the majority of adult 

alewife, it follows that the high entrainment densities on the southern shore 

may be the resul t of eggs and 1 arvae bei ng transported by countercl ockwi se 

inshore currents, and subsequently being entrained by intakes on the southern 

shore. 

Alewife Entrainment - Lakewide 

The maximum numbers of alewife eggs and larvae entrained by all water 

intakes on Lake Michigan were estimated to be 7.39 x 1010 and 1.31 x 109 , 

respectively, assuming capacity flow at all intakes (Table 14). Under these 

conditions, conventional power plants would account for approximately 54% of 

the total entrained alewife eggs, the Ludington plant would account for 8%, 

and municipal/industrial intakes for 38%. The relative percentage distribution by plant type .for alewife larvae would be 28% by conventional power 

plants, 56% by Ludington, and 16% by the municipal/industrial plants. Since 

conventional power plants, as a group, typically withdraw ",50% of capacity 

flows on an annual basis, and most other intakes are assumed to operate near 

capacity flow, we estimate that at least 5 x 1010 alewife eggs and 1 x 109 

20 
Table 12. Estimated total numbers of alewife, rainbow smelt, and yellow perch eggs and larvae entrained 

each month during the sampling periods at all 15 sampled power plants; estimated annual totals by 

extrapolation to full year for each plant (1975). 

Total Flow Alewife Smelt Perch 

(m3 ) Eggs Larvae Eggs Larvae Eggs [arvae 

January 1.63 x 108 0 0 0 6.00 x 100 0 0 

February 1.83 x 108 0 0 0 5.42 X 104 0 0 

March 2.30 x 108 0 0 1.01 X 105 4.48 X 104 1.24 X 104 0 

April 5.54 x 108 8.24 X 105 0 5.80 X 107 3.72 X 104 0 0 

May 9.07 x 108 2.30 X 108 3.63 X 105 2.83 X 107 5.44 X 106 1.01 X 106 4.49 X 105 

June 9.96 x 108 6.17 X 109 6.28 X 107 3.41 X 106 6.55 X 105 5.35 X 106 1.22 X 105 

July 1.05 x 109 3.88 X 109 5.82 X 107 0 2.37 X 106 1.26 X 104 2.96 X 104 

August 1.06 x 109 1. 77 X 108 8.22 X 106 0 4.53 X 106 0 0 

September 7.73 X 108 3.41 X 105 3.56 X 106 0 3.72 X 106 0 0 

October 6.30 x 108 0 1.13 X 105 0 2.81 X 106 0 0 

November 2.67 x 108 0 8.03 X 102 0 9.40 X 105 0 0 

December 2.19 x 108 0 1.30 X 101 a 4.25 x 10" D 0 

Total observed 7.04 x 109 1.05 X 10 10 1.33 X 108 8.98 X 107 2.06 X 107 6.38 X 106 6.01 X 105 

Estimated annual 

total 1.11 x 10 10 2.01 X 108 3.10 X 108 2.71 X 107 6.77 X 106 6.12 X 105 

Table 13. Estimated total numbers of alewife, rainbow smelt, and yellow perch eggs and larvae entrained 

during the sampling periods at each of the 15 sampled power plants; estimated annual totals by 

extrapolation to full year for each plant (1975). 

Total Flow Alewife Smelt Perch 

(m3 ) Eggs [arvae Eggs [arvae Eggs [arvae 

Zion 5.52 x 108 4.73 X 108 4.39 X 106 4.47 X 107 3.13 X 106 N/A N/A 

Cook 1.30 x 109 6.21 X 108 6.51 X 107 7.86 X 106 2.91 X 105 4.05 X 106 6.37 X 104 

Bai lly 6.16 x 108 3.86 X 109 3.80 X 107 4.14 X 106 2.87 X 105 1.24 X 104 1.42 X 10" 

Michigan City N/A N/A N/A N/A N/A N/A N/A 

Pull i am 1. 52 x 108 2.93 X 108 4.84 X 10" 6.87 X 105 2.52 X 104 2.32 X 106 5.17 X 105 

Kewaunee 5.33 x 108 4.71 X 107 6.03 X 105 9.85 X 105 9.45 X 106 N/A N/A 

Point Beach 8.08 x 108 4.11 X 106 3.31 X 105 0 1. 21 X 106 N/A N/A 

Port Washington 3.42 x 108 2.70 X 106 2.95 X 105 1.16 X 105 2.99 X 105 0 5.64 X 103 

Lakeside 1.41 x 108 3.07 X 10 6 6.29 X 105 0 0 N/A N/A 

Oak Creek 8.93 x 108 6.14 X 106 1.59 X 106 5.96 X 104 4.41 X 106 N/A MfA 

Waukegan 4.08 x 108 2.93 X 109 1.18 X 107 2.73 X 107 1.37 X 105 N/A N/A 

Stateline 5.26 x 108 7.12 X 108 2.97 X 106 3.61 X 106 8.07 X 104 N/A N/A 

Mi tchell 2.24 x 108 1.51 X 10 9 7.41 X 106 2.32 X 105 1.34 X 106 MIA MIA 

Campbell 3.35 x 108 6.48 X 104 2.25 X 103 1.24 X 102 . 1.49 X 103 0 0 

Palisades 9.94 x 107 0 7.00 x 100 1. 40 X 101 1. 30 X 101 0 0 

Big Rock 1.07 x 108 0 1.05 X 10 1 5.47 X 102 1.43 X 102 0 0 

Total observed 7.04 x 109 1.05 X 10 10 1.33 X 108 8.98 X 107 2.06 X 107 6.38 X 106 6.01 X 105 

Estimated annual 

total 1.11 x 10 10 2.01 X 108 3.10 X 108 2.71 X 107 6.77 X 106 6.12 X 105 

21 
alewife larvae were entrained by all water intakes on Lake Michigan in 1975. 

Table 15 shows the estimated maximum numbers of alewife eggs and larvae 

entrained in 1975 by statistical district. From these estimates, it is clear 

that the majority of alewife eggs and larvae are entrained in Illinois, 

Indiana, and MM6, the districts with the greatest water withdrawal. Our 

estimates for di stri ct MM6 (primarily the Ludi ngton Pump Storage Pl ant) are 

based on the assumption that inshore densities of alewife eggs and larvae in 

that district are equal to those in district MM8, since no intakes were 

sampled in MM6. Our estimation procedure seems to yield reasonable estimats 

for "unsampl ed" intakes (not in our data base but observati ons avail abl e) in 

districts where sampling was performed (Table 8). 

The total number of alewife larvae entrained at the sampled intakes 

(Table 12) represents approximately 1.8% of the total number of eggs entrained 

by those intakes indicating a 98% mortality between egg and larval stages of 

development. Extrapolation of these values to all intakes on Lake Michigan 

(Table 14) also indicates a 98% mortality between egg and larval stages. For 

a number of reasons, thse estimates may not refl ect actual mortal ity rates 

between the egg and larval stages of alewife in Lake Michigan. This crude 

approach assumes that (1) power plant intakes "samplell eggs and larvae at 

equal efficiencies which may not be true; and (2) the sampled intakes provided 

unbiased estimates of actual egg and larval densities in Lake Michigan 

waters. Many studies of fish population dynamics have shown that clupied 

species tend to undergo high mortal ity rates during the first year of life, 

and it is usually assumed that mortality from egg to adult stages exceeds 99%. 

Rainbow Smelt Entrainment - Sampled Intakes 

The major peri ods of entrai nment were March through June for smel t eggs 

and May through November for smelt larvae (Table 12). Peaks in total entrainment at the sampl ed pl ants occurred in Apr; 1 for eggs and in May and August 

for larvae. No smelt eggs were entrained between July and February but at 

least 3 x 104 smelt larvae were reported each month except for January. The 

monthly totals for smelt larvae in Table 12 show a bimodal distribution with 

time (i .e., peaks in May and August) and may indicate either (1) altered 

spatial distribution of larvae over time, or (2) the existence of two or more 

separate spawning times lakewide. 

An estimated total of 3.10 x 108 smelt eggs and 2.71 x 107 smelt larvae 

were entrained at the 15 sampled intakes in 1975. The sampling periods were 

not initiated soon enough at some of the southern basin intakes to adequately 

characterize egg entrainment; therefore, the annual estimate of entrained eggs 

is approximately three times the observed value. Larval entrainment was 

adequately characterized during the sampling periods at most of the sampled 

intakes. 

Figures A.1.f-A.16.f show the time-dependent nature of smelt egg entrainment and indicate peak densities )1 egg/m3 at the Zion and Waukegan plants in 

April. Numerous plants had peak densities >0.1 egg/m3 (e.g., Cook, Bailly, 

Pulliam, Kewaunee, and Stateline). Extremely low egg densities and total egg 

entrai nment were observed at Poi nt Beach and Campbell, despi te substanti al 

impingements of smelt at these plants (Table 4). 

Smelt egg entrainment commenced about the same time as smelt impingement 

22 
Table 14. Estimated total numbers of alewife, smelt, and yellow perch eggs and larvae entrained at sampled power plants, unsampled power plants, and municipal/industrial intakes on Lake Michigan, assuming design flow operation 

(1975). 

Total Flow Alewife Smelt Perch 

(m3 ) Eggs [arvae I:ggs [arvae Eggs [arvae 

15 sampled power plants 1.97 x 1010 3.66 X 1010 3.40 X 108 4.06 X 108 6.37 X 107 1. 67 X 107 2.54 X 106 

Unsampled power plants 9.67 x 108 3.15 X 109 2.57 X 107 5.10 X 106 1.54 X 106 1.20 X 10'" 1.67 X 10'" 

Total conventional plants 2.07 x 10 10 3.97 X 1010 3.66 X 108 4.11 X 108 6.52 X 107 1.67 X 107 2.55 x 106 

Ludington P.S. plant 2.11 x 1010 5.85 X 109 7.30 X 108 5.99 X 107 2.33 X 106 3.08 X 107 5.28 X 105 

Total all power plants 4.18 x 1010 4.56 X 1010 1.10 X 109 4.71 X 108 6.75 X 107 4.75 X 107 3.08 X 106 

Total municipal/industrial 6.51 x 109 2.83 X 10 10 2.14 X 108 1.44 X 108 1.53 X 107 6.49 X 105 1.81 X 105 

Total all intakes 4.83 x 10 10 7.39 X 1010 1.31 X 109 6.15 X 108 8.28 X 107 4.81 X 107 3.26 X 106 

Table 15 •. Estimated total annual entrainment of alewife eggs and larvae at 

all water lntakes within each statistical district on Lake Michigan (1975) 

assuming deSign flow operation at all intakes. ' 

Total Flow Denslty Eggs Larvae 

Number Densl ty Number District (m3) (N/m3) (N/m3) 

WMJ. 7.99 x 108 1.44 x 100 1.15 X 109 1.99 x 10-4 1. 59 x 105 Wr.2 0 0 0 0 0 WM3 0 0 0 0 0 WM4 2.39 x 109 4.85 X 10-2 1.16 X lOB 7.80 x 10-4 1.87 X 106 

WII!i 2.55 x 109 9.61 X 10-3 2.45 X 107 1.66 X 10-3 4.24 X 106 

Wfofi 2.51 x 109 7.01 X 10-3 1.76 X 107 1.66 X 10-3 4.15 X 106 

III i n01 s 6.46 x 109 3.68 x 100 2.38 X 1010 1. 66 X 10-2 1.07 X lOB Indiana 8.10 x 109 5.18 x 100 4.20 X 10 10 4.19 X 10-2 3.40 X lOB Mfo'B 3.42 x 109 2.77 X 10-1 9.47 X 108 3.46 X 10-2 1.18 X lOB MM7 7.03 x 108 2.77 X 10-1 2.96 X 107 3.46 X 10-2 3.68 X 106 Mfofi 2.11 x 1010 2.77 X 10-1 5.85 X 109 3.46 X 10-2 7.30 X lOB MII!i 0 0 0 0 0 MM4 3.32 x 107 0 0 9.47 X lO-B 3.20 x 100 

MM3 1.02 X lOB 0 0 9.47 X lO-B 9.60 x 100 MM2 9.95 x 106 0 0 9.47 X lO-B 9.00 X 10-1 MMJ. 9.08 x 107 0 0 9.47 X 10-8 9.00 x 100 

Total all 

intakes 4.83 x 1010 7.38 X 1010 1.31 X 109 

23 
increased in the spring at some plants (Cook, Bailly, Pulliam, Waukegan, 

Stateline, and Big Rock), but at other plants it was delayed at least a month 

relative to the increase in impingement (Kewaunee, Port Washington, and Oak 

Creek). Since a number of plants impinged smelt over the winter months and 

the normal hatching time for smelt eggs ranges from 3-5 weeks, it is difficult 

to determi ne if a 1 ag peri od exi sts between inshore mi grati ons and spawni ng. 

Although egg entrainments typically were confined to less than three months at 

any plant, larval entrainment (Figs. A.1.g-A.16.g) was spread out over 6-9 

months at some plants (e.g., Kewaunee and Oak Creek). This pattern must 

result from the transport of eggs and larvae spawned at remote locations and 

from the slow development of smelt larvae into motile juveniles that are too 

large to be entrained. Thus, smelt young are vulnerable to entrainment for 

longer periods of time and by more water intakes than are alewife young. Peak 

densities of larvae were ~0.1/m3 at Zion, Kewaunee, and Mitchell, and ~0.01/m3 

at Bailly, Point Beach, Port Washington, and Oak Creek. Very low densities of 

smelt larvae (~0.0001/m3) were entrained at Lakeside, Campbell, Palisades, and 

Big Rock. Smelt larval densities were equal to or greater than egg densities 

at Kewaunee, Point Beach, Port Washington, Oak Creek, and Mitchell, another 

indication of long-range transport and extended vulnerability of planktonic 

smelt to entrainment. 

The estimated total numbers of smelt eggs and larvae entrained at each of 

the sampled intakes are given in Table 13. Eighty percent of the smelt eggs 

entrained by sampled intakes were taken at the Zion and Waukegan plants, while 

98% were entrained by five plants in the southern basin (Zion, Cook, Bailly, 

Waukegan, and Statel i ne). However, entrai nment of smel t 1 arvae was not concentrated in the southern basi n, but was nearly equal between northern and 

southern pl ants taken as groups. In the north, Kewaunee and Poi nt Beach 

accounted for 52% of the 1akewide total (observed) and in the south, Zion, Oak 

Creek, Mitchell, Waukegan, and Port Washington accounted for 45% of the total 

entrained smelt larvae. This difference between egg and larval distribution 

indicates that sUbstantial smelt spawning may be occurring on the northwestern 

shore of Lake Michigan, as well as in the southern basin. 

Smelt Entrainment - Lakewide 

The maximum numbers of smelt eggs and 1 arvae entrai ned by all water 

intakes on Lake Michigan were estimated to be 6.15 x 108 and 8.28 x 107 , 

respectively, assuming capacity flows at all water intakes (Table 14). Under 

these conditions conventional power plants would account for 67% of the total 

entrained smelt eggs, the Ludington plant would account for 10%, and the 

municipal/industrial intakes would entrain 23% of the total eggs. The relative distribution of entrained smelt larvae by plant type would be 79% by 

conventional power plants, 3% by the Ludington plant, and 18% by 

municipal/industrial intakes. Under normal flow assumptions, we estimate that 

at least 5 x 108 smelt eggs and 5 x 107 smelt larvae were entrained by all 

water intakes on Lake Michigan in 1975. The estimated maximum numbers of 

smelt eggs and larvae entrained in 1975 within each statistical district are 

given in Table 16. These estimates indicate that the majority of smelt eggs 

are entrained in Illinois while smelt larvae are heavily entrained in 

Illinois, Indiana, WM4, and WM6. The accuracy of these estimates is indicated 

by the good agreement between our estimates for "unsampl edll intakes and 

observed data at those intakes for smelt eggs and larvae (Table 8). 

24 

ML 
Table 16. Estimated total annual entrainment of rainbow smelt eggs and larvae 

at all water intakes within each statistical district on Lake Michigan (1975), 

assuming design flow operation at all intakes. 

Eggs Larvae 

Total Flow Density Number Densi ty Number 

District (m3 ) (N/m3) (N/m3) 

WMl. 7.99 x 108 5.14 X 10-3 4.10 X 106 1. 37 X 10-4 1.09 X 105 

WM2 0 5.14 x 10-3 0 1.37 X 10-4 0 

WM3 0 2.52 x 10-3 0 1.03 X 10-2 0 

WM4 2.39 x 109 2.52 X 10-3 6.03 X 106 1.03 X 10-2 2.46 X 107 

W/ofi 2.55 x 109 2.16 x 10-4 5.51 X 105 3.99 X 10-4 1.02 X 106 

Wr.Ii 2.51 x 109 7.57 X 10-5 1.90 X 105 4.45 X 10- 3 1.11 X 107 

Illinois 6.46 x 109 7.43 X 10-2 4.80 X 108 4.38 X 10- 3 2.83 X 107 

Indiana 8.10 x 109 6.61 X 10-3 5.36 X 107 1.84 X 10-3 1.49 X 107 

Mr-B 3.42 x 109 2.84 X 10-3 9.70 X 106 1.10 X 10-4 3.77 x 105 

MM7 7.03 x 108 2.84 X 10-3 3.02 X 105 1.10 X 10-4 1.44 X 104 

Mr.Ii 2.11 x 1010 2.84 X 10-3 5.99 X 107 1.10 X 10-4 2.33 X 106 

M/ofi 0 0 0 0 0 

MM4 3.32 x 107 4.94 X 10-6 1.64 X 102 1. 29 X 10-6 4.27 X 101 

MM3 1.02 x 108 4.94 X 10-6 5.03 X 102 1.29 X 10-6 1.31 X 102 

MM2 9.95 x 106 4.94 X 10-6 4.92 X 101 1.29 X '10-6 1.28 X 101 

MMl. 9.08 X 107 4.94 X 10-6 4.49 X 102 1.29 X 10-6 1.17 X 102 

Total all 

intakes 4.83 x 1010 6.14 X 108 8.28 X 107 

The total number of smelt larvae entrained at the sampled intakes (Table 

12) represents approximately 9% of the total number of smelt eggs entrained at 

these intakes and indicates a 91% mortality between eggs and larvae. From 

Table 14, the lakewide estimates indicate an 87% mortality between egg and 

larval stages of development. These estimates of mortality between egg and 

larval stages of smelt in Lake Michigan should be used with caution, for the 

same reason given in the discussion of alewife egg-larvae mortality. 

Yellow Perch Entrainment - Sampled Intakes 

Yellow perch eggs were entrained between March and July, with peak 

entrainment occurring in May and June. Yellow perch larvae wre entrained 

between May and July, with major entrainment in May and June (Table 12). No 

eggs or larvae were entrained between August and February. An estimated total 

of 6.77 x 106 eggs and 6.12 x 105 larvae were entrained at the 15 sampled 

intakes in 1975 (Table 13). Two power plants (Pulliam and Cook) accounted for 

99.8% of the total eggs and 96.6% of the total larvae entrained by the sampled 

intakes. However, it must be noted that a large fraction of the plants that 

were sampled did not identify (report) perch eggs and larvae; therefore, the 

actual di stri buti on of immature perch may be somewhat different than that 

reflected by Table 13. 

Figures A.2.h-A.16.h and A.2.i-A.16.i show the entrainment rates 

(densities) of yellow perch eggs and larvae, respectively, at each sampled 

plant (only those plants that identified perch eggs or larvae were 

incl uded). Of the three pl ants that reported yell ow perch eggs, Pull i am 

recorded the highest densities (~O.3 eggs/m3 ), followed by Cook (~0.04 

eggs/m3 ), and Bailly (~0.001 eggs/m3 ). Although every sampled plant impinged 

some ye 11 ow perch (Table 4), Pull i am and Cook imp; nged ~95% of the observed 

25 
totals. This indicates that minor entrainment of eggs and larvae probably occurred at the majority of plants. 

The earliest yellow perch egg entrainment was recorded at the Bailly 

plant in March, while at Pulliam and Cook egg entrainment started in April to 

May and peaked in May to June. Yellow perch were impinged at variable rates 

prior to the egg entrainment and no clear spawning influx was evident. Larval 

entrainment began )3 weeks after the initial appearance of eggs at each of the 

three plants that recorded both eggs and larvae. Maximum densities of larvae 

were observed at Pulliam (~0.04 larvae/m3). The yellow perch larvae entrained 

by Port Washi ngton may have been transported from the northwestern shore by 

lake currents. 

Yellow Perch Entrainment - Lakewide 

The maximum numbers of yell ow perch eggs and 1 arvae entrai ned by all 

water intakes on Lake Michigan were estimated to be 4.81 x 107 and 3.26 x 106 , 

respectively, assuming capacity flows at all intakes (Table 14). Under these 

conditions, conventional power plants would account for ~35% of the total 

entrained perch eggs, the Ludington plant would account for 64% of the total, 

and muniCipal/industrial intakes for ~1% of the total. The relative distribution of yellow perch larvae by plant type would be: 78% by conventional power 

pl ants, 16% by Ludington, and 6% by muni ci pa 1 /industri al intakes. Under 

normal flow assumptions, we estimate that ~4 x 107 yellow perch eggs and 1 x 

106 yellow perch larvae were entrained by all water intakes on Lake Michigan in 1975. 

The estimated maximum numbers of yellow perch eggs and larvae entrained 

within each statistical district in 1975 are given in Table 17. These estimates indicate the the majority of yellow perch eggs and larvae were entrained 

in MM6, MM1, and MM8. Unfortunately, no observations were available for 

Table 17. Estimated total annual entrainment of yellow perch eggs and larvae 

at all water intakes within each statistical district on Lake Michigan (1975). 

assuming design flow operation at all intakes. 

Eggs Larvae 

Total Flow Density Number Density Number 

District (m3) (N/m3) (N/m3) 

WMl. 7.99 x 108 1. 51 X 10-2 1.21 X 107 3.04 X 10-3 2.43 X 106 

WM2 0 1.51 x 10-2 0 3.04 X 10-3 0 

WM3 0 N/A 0 N/A 0 

WM4 2.39 x 109 N/A N/A N/A N/A 

Wr.f.i 2.55 x 109 0 0 1.14 X 10-5 2.90 x 10" 

Wr.f5 2.51 x 109 N/A N/A N/A N/A 

Illinois 6.46 x 109 N/A N/A N/A N/A 

Indiana 8.10 x 109 2.01 X 10-5 1.63 X 105 2.29 X 10-5 1.86 X 105 

Mt-B 3.42 x 109 1.46 X 10-3 4.98 X 106 2.51 X 10-5 8.56 x 10" 

MM7 7.03 x 108 1.46 x 10-3 1.55 x 105 2.51 X 10-5 2.66 X 103 

Mr.f5 2.11 x 1010 1.46 X 10- 3 3.08 X 107 2.51 X 10-5 5.28 X 105 

Mr.f.i 0 0 0 0 0 

MM4 3.32 x 107 0 0 0 0 

MM3 1.02 x 108 0 0 0 0 

MM2 9.95 x 106 0 0 0 0 

MMl. 9.08 x 107 0 0 0 0 

Total all 

intakes 4.83 x 1010 4.81 X 107 3.26 X 106 

26 
intakes not included in our data base; thus, no comparisons can be made 

between our estimates for lIunsampledll intakes and actual observations. 

The total number of yellow perch larvae entrained at the sampled intakes 

(Tab 1 e 13) represents ~9% of the total number of entrai ned perch eggs and 

indicates a 91% mortality. From Table 14 a lakewide estimate indicates a 93% 

mortal ity between egg and 1 arval stages of development. These estimates may 

not reflect actual mortality rates between perch egg and larval stages in Lake 

Michigan. 

FACTORS AFFECTING IMPINGEMENT AND ENTRAINMENT 

Effects of Intake Type 

As of 1975, three types of water intakes were used by the electrical 

uti 1 i ty industry on Lake Mi chi gan: canal s (CNL), offshore open bays (OOB), 

and porous dikes (PO). Six of the 16 sampled power plant intakes are canals, 

four are offshore open bays, and six are porous dikes (Table 1). A number of 

factors, besides intake type, probably affected the obsrved impingement and 

entrainment densities at the sampled intakes: e.g., flow rate, location, and 

most important, the local inshore densities of each species/lifestage. 

Inshore densi ti es of most speci es are hi ghly vari abl e in space and no data 

were available that would allow corrections of observed intake densities for 

spatial differences in fish abundance (i.e., impingement/entrainment densities 

at each sampled intake could not be normalized for local abundances). Despite 

these problems, we made statistical comparisons of the lakewide mean densities 

between the three types of water intakes. Intakes of each type were sampled 

in each basin and on each shore of Lake Michigan. 

Al ewife 

The results of statistical comparisons between lakewide impingement 

densities at each type of intake are presented in Table 18. Alewife impingement densities (rates) tended to be significantly higher at canal intakes in 

summer, fall, and winter, and significantly higher at offshore open bay 

intakes in spring. A similar trend was found when all sampled intakes were 

grouped into lIoffshorell or lIonshorell locations: i.e., onshore intakes 

impinged significantly higher numbers of alewife in summer and winter, while 

offshore intakes impinged more alewife in spring. Figure 2 shows the annual 

mean densities of alewife at each of the sampled intakes, grouped by type. It 

is apparent from this arrangement of the data that (1) the Zion plant experienced an inordinately high density of impinged alewife compared to other OOB 

intakes, and (2) excluding Zion from the OOB group would result in canals 

having the highest annual mean density. This indicates that the Zion site was 

relatively high in alewife abundance and that the OOB intake design (without 

the behavioral barrier-net) is not very protective of alewife. Figure 2 also 

shows that the intakes sited on the western and southern shores of Lake 

Michigan experience the highest annual impingement densities of alewife, 

regardless of the intake type. 

A statistical comparison of lakewide entrainment densities of alewife 

eggs and larvae between intake types is presented in Table 19. Canal and 

porous dike intakes entrained statistically equal mean densities of alewife 

27 

- ------- -~- --- ----------
101~------------~------------r-------------~----------~ 

~ 

o 

o 

o 

)0-

r-

(f) 

~ o 

r- 1O-2!: z 

w 

::;: 

t.:l 

Z 

0.. 

::;: 

~ 1O-3 l,-

x ZIon 

• 

x Kewaunee 

x D. C. Cook 

x Palisades 

x Port WashIngton 

x Campbell 

x POInt Beach x StatelIne 

~ MItchell x Bdi11y 

x I,lkeslue 

X Blg Rock 

lO-4~------------~------------__ ~ ______________ ~ ____________ ~ 

OPEN SRi CRNRL POROUS DIKE 

Fig. 2. Mean annual densities of impinged alewife at each 

sampled intake (1975). Circles represent means for each 

intake type. 

101~------------'--------------.------------~r-----------~ 

~ Wi!: ~ 

(f) 

Z 

W 

o 

rz 

~ 10-21:- z 

cr 

a:: 

rz 

w 

ZIon 

l! D. C. Cook 

• 

x Kewaunee 

x Waukegan x M>tchell 

~ Pulliam • X StatelIne 

x LakesIde - * Oak Creek Port Washington x Point Beach 

x Campbell 

10-4.L-______________ ~P~a~1~is~a~d~es~-------L---------------L---------------J 

I 

OPEN SRi CRNRL POROUS DIKE 

Fig. 3. Mean annual densities of entrained alewife eggs at 

each sampled intake (1975). Circles represent means for 

each intake type. 

28 
eggs while the densities entrained by OOB intakes were significantly lower. 

Onshore intakes entrained significantly higher densities of alewife eggs than 

those entrained by offshore intakes. The exact opposite relationship was 

found for al ewife 1 arvae: i.e., OOB > CNL = PD and offshore > onshore. 

Figures 3 and 4 show the mean annual densities of alewife eggs and larvae, 

respectively, entrained by each sampled intake. The apparent high abundance 

of adult alewife on the western shore of Lake Michigan (Fig. 2) is reversed 

for the entrai nment of eggs and 1 arvae: i.e., canal intakes on the western 

shore (Oak Creek and Port Washington) entrained relatively few alewife eggs 

and larvae compared to intakes sited on the southern shores. 

Table 18. Statistical comparisons between lakewide monthly mean impingement densities of alewife, smelt, and yellow perch for 

intake locations and types. a 

Algwife Smelt Yellow Perch Inta~e [ocatl0n~ Inta~e Tl~ee Inta~e [ocatl0n Inta~e Type Inta~e [ocatlon Inta~e Type IIonth Ons~ore Offs~ore OOB CR[ PO Ons~ore Offs~ore Mil CFI[ PO Onshore 

January A A AB A B B A A B A A 

February A B B A B B A A A B A 

Mlrch B A A B B B A A B B A 

April A A A B A A B B A B A 

Mly B A A B B B A B A B A 

June A B B A B A B B A B A 

July A B C A B A B B A B A 

August A B B A B A B B A B A 

September A A B A C A B B A B A 

October A A B A B B A B B A A 

November A A A A A B A A A A A 

December A B B AB A B A A A B A 

a OOB = offshore open bay; CNL = canal; PO = porous dike. 

b t-test A > B > C. c AOV a = 0.05. 

Table 19. Statistical comparisons between lakewide annual mean entrainment densities of each species-life stage for 

intake locations and types. a 

Intake Locationb Intake TypeC 

Species/Stage Ons~ore Offshore OOB CNL PD 

Alewife eggs A B B A 

Alewife larvae B A A B 

Rainbow smelt eggs B A A B 

Rainbow smelt larvae B A A B 

Yellow perch eggs A A A A 

Yellow perch larvae A B B A 

~ OOB = offshore open bay; CNL = canal; PD = porous dike. 

t-test} A > B > C. c AOV a = 0.05. 

A 

B 

C 

B 

Offs~ore OOB CN[ 

B B A 

B B A 

A B A 

B B A 

B B A 

B B A 

B B A 

B B A 

B B A 

B B A 

B B A 

B B A 

A different approach to the same question regarding intake-type effects 

was applied whereby regional and temporal differences in abundance were eliminated by comparing monthly mean densities of a species/lifestage between 

29 

PO 

B 

B 

B 

B 

B 

B 

B 

B 

B 

B 

B 

B 
100~------------~----~----__ ~ ______________ ~ __________ ~ 

1= 10-2 =- ~ 

If) 

z 

w 

o 

tZ 

'i:! 10-3 =- z 

~ 

a: 

a: 

fz 

w 

x Zion 

• 

x D. C. Cook 

x Kewaunee 

x Waukegan 

x Oak Creek 

X Port WashIngton 

x Pullum 

x Mitchell 

• 

x Stateline 

X Lakeside 

x Point Beach 

10-5~ ____________ -+~pa~1~i~sa~d~e~s ______ -4~C~am~plb~el~i~ ______ ~ ____________ ~ 

, 

OPEN BRY CRNRL POElOUS DIKE 

Fig. 4. Mean annual densities of entrained alewife larvae 

at each sampled intake (1975). Circles represent means for 

each intake type. 

100·~------------~------------~--------------r-------------' 

>-

tV; 1O-2 b- z 

w 

o 

f-

:z 

W 

E 

t!) 

Z 

~ 1O-3b-

~ Kewaunee 

Zion 

• 

X D. C. Cook 

x 

X 

• 

X 

X 

X 

X 

Oak Creek 

Port Washington X Point Beach 

PullIam 

• 

Waukegan -

MichIgan City Bailly 

X Big Rock 

Campbell X Stateline -: 

X Mitchell x Lakeside 

10-ij~ ____________ ~X~P~al~i~sa~d~e~s ______ ~ ______________ ~ ____________ --J 

OPEN BRY CRNRL POROUS DIKE 

Fig. 5. Mean annual densities of impinged smelt at each 

sampled intake (1975). Circles represent means for each 

intake type. 

30 
"adjacent" intakes of different designs. Tables 20, 21, and 22 present the 

stati sti cal compari sons between al ewife densiti es at II adjacentll intakes that 

were sampled at the same time. Alewife imingement densities (Table 20) were 

significantly higher in most months at four canal intakes (Waukegan, Port 

Washington, Oak Creek, and Michigan City) that were compared with "adjacent" 

intakes of other types. The very high alewife impingement at Zion through May 

1975 is reflected in the Zion-Waukegan comparison, but the significantly 

higher densities at Waukegan from June through December indicate the relative 

efficiency of canal intakes for entrapping alewife. 

Two of the comparisons in Table 20 are between similar "adjacent" intakes 

(2 canals and 2 porous dikes) and they clearly show that very similar intakes 

in the same region of the ·lake impinge alewife at significantly different 

rates at least eight months of the year: ; .e., Port Washington> Oak Creek 

for 8 out of 12 months, Stateline> Mitchell for 4 months during alewife 

spawning runs, but Mitchell> Stateline during 4 months in fall and winter. 

No explanation is apparent for the differences between the densities of alewife impinged at the two canal intakes (Port Washington vs. Oak Creek) other 

than the distance of ..... 37 miles between them. The two porous dikes (Mitchell 

vs. Stateline) are separated by ..... 20 miles and are slightly different in that 

the Mitchell intake extends further offshore and utilizes an electric fish 

screen in the intake forebay. 

Tables 21 and 22 present the' intake-pair comparisons for entrainment 

densities of alewife eggs and larvae, respectively. Only one canal and one 

OOB intake entrained consistently higher densities of eggs (i.e., Waukegan vs. 

Zion and Kewaunee vs. Point Beach). All other comparisons were equivocal 

except that Mitchell·s porous dike intake rather consistently entrained more 

alewife eggs/unit volume than the porous dike at Stateline. Entrainment 

densities of alewife larvae were higher at canal intakes in late summer, while 

densities entrained by porous dikes may have been higher in early summer. The 

higher densities of larvae at Mitchell as compared to those at Stateline may 

reflect the apparent lakewide difference between offshore and onshore intakes 

(Table 19) 0 

In conclusion, the results of lakewide and paired intake comparisons 

i ndi cate that, wi th the except; on of the Zi on intake operated wi thout a protective net, canal and onshore PD intakes impinge more alewife per unit volume 

than OOB or OPD intakes. Onshore intakes, and offshore porous dikes apparently entrain more alewife eggs/unit volume, while offshore open bays entrain 

higher densities of alewife larvae. These indications may reflect the following: (1) spawning alewife tend to be anadromous and may seek harbors, rivers, 

and canals despite reverse flow characteristics of intake canals; (2) alewife 

eggs are demersel (negatively buoyant) but remain semi-planktonic and may be 

equally vulnerable to onshore and offshore intake types; and (3) alewife 

larvae are semi-planktonic and may concentrate near the bottom in offshore 

areas where open bay intakes are located. The comparisons between similar 

lIadjacent" intakes indicate the degree of spatial variability in abundances of 

adult and young alewife, and demonstrate the potential errors associated with 

comparisons of this type. 

Rainbow Smelt 

Lakewide annual impingement densities of rainbow smelt (Table 18) indi31 
Tabl e 20. Statistical comparisons of the monthly mean densities (N/10003 ) of impinged alewife between dissimilar and similar intakes that are "adjacent" to 

one another. Underlined densities are significantly higher (a = 0.05). 

January February Mirch April Miy June July August September October November December 

Kewaunee vs. Point Beach 

04/01/75-02/28/76 

OOB .00008 .00033 .00251 .18628 .92340 .40736 .35052 .17825 .23001 .45843 0 

PD .00017 -:ummr .00021 .73129 4.29441 2.84051 .73800 -:o543T .28655 .54113 .00021 

Waukegan vs. Zion 

05/12/75-12/31/75 

CNL 2.82230 3.54028 1.00764 .28921 .30037 .65819 .15591 .04383 

OOB 96.09213 T.1Jl:!I"ffir ---:J12IT -:1m5lr -:TJ3OT -:T5ID ~ -:oomLakeside vs. Port Washington 

03/07/75-02/26/76 

PD 0 0 0 .05499 .21484 1.01245 .25663 .05223 .00182 .00268 .12590 .01294 

CNL .00582 .00087 .00167 .31192 12.90111 22.08029 6.81306 .96535 .14267 .69851 .27349 .03304 w Lakeside vs. Oak Creek --- N 

03/07/75-02/06/76 

PD 0 0 0 .05499 .21484 1.01245 .25663 .05223 .00182 .00268 .12590 .01294 

CNL 0 0 .00149 .13458 2.77194 5.45543 3.00166 1.06960 .15047 .01571 ~ .00415 --- --- Bailly vs. Michigan City 

12/03/75-06/28/76 

PD .00042 .00021 .00131 .12215 .78674 1.55160 .00117 

CNL u--- .00016 .55357 1. 21574 2.14510 2.46038 .00244 --- Oak Creek vs. Port Washington 

03/04/75-02/25/76 

CNL 0 0 .00133 .13458 2.77194 5.45543 3.00166 1.06960 .15047 .01571 .02490 .00415 

CNL .00582 .01064 .00161 .31192 12.90111 22.08029 6.81306 .96535 .14267 .69851 .27439 .03304 --- Mitchell vs. Statel ine 

05/03/75-03/30/76 

PD .00032 .00045 0 1.38272 1.02870 .18293 .01530 .00121 .00976 .66217 .13175 

PD .00028 0-- 0 2.84351 ---

2.05157 .48243 .01315 .02828 -:mlT54 ~ ~ 
cate that canal intakes impinge significantly more smelt/unit volume between 

April and September, while significantly higher densities are impinged by' 

porous dikes in late fall, and by offshore open bays in early spring. Offshore intakes, as a group, impinge significantly higher densities of smelt 

from fall to early spring, while onshore intakes impinge higher densities in 

April and summer months. Figure 5 presents the annual mean impingement densities of smelt at each sampled intake and clearly indicates the relatively high 

abundance of smelt on the western shore of Lake Michigan: i.e., regardless of 

intake type, the highest annual densities of smelt occur at intakes on the 

Wisconsin and northern Illinois shores. On an annual basis, the mean density 

of smelt impinged at canal intakes is substantially higher than those at OOB 

and PD intakes, but this difference may be a result of the higher number of 

canal intakes on the western shore of the lake. The comparisons of monthly 

smelt impingement densities between lIadjacent" pairs of intakes (Table 23) 

sugges ts that canal intakes impi nge s i gnifi cantly more smelt than OOB or PD 

intakes throughout most of the year, with the exception of late fall (Zion vs. 

Waukegan). Porous dikes (Point Beach vs. Kewaunee) may impinge higher dens;-

ties of young of the year in late summer. Comparisons of similar "adjacent" 

intakes show consistently higher densities at Oak Creek compared to Port 

Washington and seasonal differences between Mitchell and Stateline: i.e., 

between June and December the onshore porous dike at Stateline impinged fewer 

smelt/unit volume than the more offshore porous dike at Mitchell and, in late 

winter, the reverse was true. 

Rainbow smelt eggs were entrained at significantly higher rates 

(densi ti es) by offshore open bay intakes and by offshore intakes as a group 

(Table 19). The mean annual densities of entrained smelt eggs (Fig. 6) were 

highest at intakes on the southern basin of Lake Michigan and apparently were 

highest at OOB intakes. Unfortunately. the major period of smelt egg entrainment (early spring) either was not sampled by some utilities or was sampled in 

different years; therefore, the statistical comparisons between lIadjacent" 

intakes were limited to very few months (Table 24). Despite these problems, 

the comparisons do indicate significantly higher densities of entrained smelt 

eggs at OOB intakes (Kewaunee vs. Point Beach and Zion vs. Waukegan). 

Rainbow smelt larvae also were entrained at significantly higher rates 

(densi ti es) by offshore open bay intakes and by offshore intakes as a group 

(Tabl e 19). Intakes on the western shore and in the southern basi n of Lake 

Michigan tended to show the highest densities of entrained smelt larvae (Fig. 

7). Table 25 presents the comparisons of smelt larval densities between 

"adjacent" intakes and reflects the lakewide trend of offshore open bays 

entraining higher densities than canal or porous dike intakes. Although Port 

Washington entrained higher densities of smelt eggs than did Oak Creek, the 

reverse was true for smelt larvae. Mitchell's porous dike (more offshore) 

consistently entrained more smelt larvae/unit volume than did the onshore 

porous dike at Stateline. 

In conclusion, the above analyses indicate that canal intakes are most 

destructive of smelt adults during the spawning season, while offshore porous 

dikes and open bays tend to impinge more smelt/unit volume during other 

periods of the year. Smelt e,ggs and larvae seem most susceptible to OOB 

intakes and offshore intakes in general. 

33 
1O- 1 .,-------r-:;-:-:-:-----,-------,...---------:J '" hon 

~ W-3r 

!2 

lJ..J 

Cl 

tZ 

~ 10-111::- :z 

~ 

a: 

cr: 

tZ 

lJ..J 

• 

x D. C. Cook 

x Kewaunee 

)( Waukegan 

• x Stateline 

)( Pulllam 

• 

x ~Iltchell 

)( Oak Creek 

X Port Washington 

. P., '<.nes Ca~bell Point Beach Lakeside 10-6iL-____________ ~.~~~~------+-.~~~------~.~~~~~=-~ 

OPEN BAY CRNAL POROUS DIKE 

Fig. 6. Mean annual densities of entrained smelt eggs at 

each sampled intake (1975). Circles represents means for 

each intake type. 

10-1~------------,_------------~-------------,,_----------~ 

1= lO-3t;-

U1 

z 

lJ..J 

Cl 

tZ 

~ 10-11 1:- z 

a: 

cr: 

tZ 

lJ..J 

10-St;-

x Kewaunee 

x Zlon • 

x D. C. Cook 

x Mitchell 

x Oak Creek 

• 

• x P01nt Beach 

X Port Washington 

x Waukegan 

x Pulliam x Stateline 

x Campbell 

Palisades Lakeside 10-6L--------------~.~~~~----~--------------~.r-------------~ 

OPEN BAY CRNAL POROUS DIKE 

Fig. 7. Mean annual densities of entrained smelt larvae at 

each sampled intake (1975). Circles represent means for 

each intake type. 

34 
Table 21- Statistical comparisons of the monthly mean densities (N/m3 ) of entrained alewife eggs between dissimilar and similar intakes that are "adjacent" 

to one another. Underlined densities are significantly higher (a = 0.05). 

January February Mlrch April Mly June July August September October November December 

Kewaunee vs. Point Beach 

04/18/75-10/31/75 

OOB 0 0 .01711 .56431 .09761 0 0 

PO 0 0 ~ -:urgg{ --:-orow 0 0 

Waukegan vs. Zion 

04/16/75-09/03/75 

CNL 0 .00587 24.34260 5.81448 .93701 .01435 

ooB 0 .00244 1.88130 ~ -:-rsm 0--

w Lakeside vs. Port Washington <.TI OS/20/75-10/28/75 

PO 0 .01301 .05450 .00432 0 0 

CNL 0 .00204 .03765 -:-ooo5J 0 0 

Lakesi de vs. Oak Creek 

OS/20/75-10/29/75 

PO 0 .01301 .05450 .00432 0 0 

CNL 0 .00536 ~ .02179 0 0 

Oak creek vs. Port Wash; ngton 

04/17/75-10/28/75 

CNL 0 0 .00536 .01754 .02179 0 0 

CNL 0 0 .00204 .03765 -:-ooo5J 0 0 

Mi tchell vs. Statel i ne 05/03/75-09/04/75 

PO 3.31866 22.47867 5.86174 .11838 .01220 

PO .09453 4. 71500 ~ .19407 .00036 
Table 22. Statistical comparisons of the monthly mean densities (N/m3) of entrained alewife larvae between dissimilar and similar intakes that are "adjacent" to one another. Underlined densities are significantly higher (a = 0.05). 

January February f.tlrch April f.tly June July August September October November December 

Kewaunee vs. Point Beach 

04/18/75-10/31/75 

OOB 0 0 0 .00315 .00149 .00441 0 

PO 0 0 0 ~ .00109 ~ .00003 

Waukegan vs. Zion 

04/16/75-09/03/75 

CNL 0 0 .01927 .07355 .01658 .08063 

OOB 0 0 .00321 -:nID!if -:mm3 .00250 

Lakeside vs. Port Washington 

OS/20/75-10/28/75 

w PO 0 .00310 .01177 0 0 0 

0'1 CNL 0 .00005 -:-ommr .00123 .00321 0 

Lakeside vs. Oak Creek 

OS/20/75-10/29/75 

PO 0 .00310 .01177 0 0 0 

CNL 0 0 -:1JOllU2" .00253 .00770 .00056 

Oak Creek vs. Port Washington 

04/17/75-10/28/75 

CNL 0 0 0 .00002 .00253 .00770 .00057 

CNL 0 0 .00004 .00018 -:1JOT23" -:-onm 0-

Mitchell vs. Statel ine 

05/03/75-09/04/75 

PO .00025 .08821 .04038 .01525 .00012 

PO 0 -:1ITID -:-nom ~ .00168 
-----~-

Table 23. Statistical comparisons of the monthly mean densities (N/IOOO m3 ) of impinged smelt between dissimilar and similar intakes that are "adjacent" to one another. Underlined densities are significantly higher (a = 0.05). 

January February r-tlrch April r-tly June July August September October November December 

Kewaunee vs. Point Beach 

04/01/75-02/28/76 

OOB .04948 .04481 .03899 .00353 .01754 .01261 .01185 .02228 .23001 .08779 .01459 

PO .08043 ~ -:uom .00572 .01899 .06966 .06159 .05637 .28655 .18391 .05555 

Waukegan vs. Zion 

05/12/75-12/31/75 

CNL .00183 .00469 .02168 .00385 .00183 .00338 .00144 .00398 

OOB 0-- 0-- -:mRlOT -:ummr ~ ~ .00637 .07176 

Lakeside vs. Port Washington 

03/07/75-02/06/76 

w PO .00014 .00164 0 0 .00118 .00121 0 0 0 .00045 .00188 0 ....... CNL .00951 .00638 .03850 .12074 .10360 .10309 .20519 .29830 .45350 .00699 .03149 .03948 

Lakeside vs. Oak Creek 

03/07/75-02/06/76 

PO .00014 .00164 0 0 .00ll8 .00121 0 0 0 .00045 .00188 0 

CNL .02838 .04445 .09196 .73320 .31172 .19883 .69027 .39366 .21710 .03461 .12181 .08033 

Bailly vs. Michigan City 12/03/75-06/28/76 

PO .00042 .00018 .00370 .00649 .01014 .00016 .00072 

CNL .00042 .00111 .00284 .00449 .00763 .00057 .00056 

Oak Creek vs. Port Washington 

03/04/75-02/25/76 

CNL .02B38 .06124 .09001 .73320 .31172 .19883 .69027 .39366 .21710 .03461 .12181 .08033 

CNL --:mr95T -:uruog- ~ -:T2U7Ir -:roJIiO"" -:T03U"9" ~ .29830 .45350 ~ ~ ~ 

Mitchell vs. Statel ine 

05/03/75-03/30/76 

PO .00034 .00010 .00010 .00052 .00095 .00121 .00076 .00073 .00026 .00009 .00164 

PO .00036 .00069 .00079 .00054 -:mmoo -:1llllYfl) ~ 0-- -:-omms- .00005 -:-ummr 
Table 24. Statistical comparisons of the monthly mean densities (N/m3) of entrained smelt eggs 

to one another. Underlined densities are significantly higher (a = 0.05). 

between dissimilar and similar intakes that are "adjacent" 

January February Mlrch April Mly June July August September October November December 

Kewaunee vs. Point Beach 

04/18/75-10/31/75 

OOB .05362 .01422 0 0 0 0 0 

PD 0 0-- 0 0 0 0 0 

Waukegan vs. Zion 

04/16/75-09/03/75 

CNL .47900 .06609 0 0 0 0 

OOB .62093 .11037 .00061 0 0 0 

Lakeside vs. Port Washington 

tAl OS/20/75-10/28/75 

ex> PD 0 0 0 0 0 0 

CNL .00210 0 0 0 0 0 

Lakeside vs. Oak Creek 

OS/20/75-10/29/75 

PD 0 0 0 0 0 0 

CNL 0 0 0 0 0 0 

Oak Creek vs. Port Washington 

04/17/75-10/28/75 

CNL 0 .00048 0 0 0 0 0 

CNL .00005 .00249 0 0 0 0 0 

Mitchell vs. Statel ine 

05/03/75-09/04/75 

PD .00681 0 0 0 0 

PD .00716 .00068 0 0 0 
------------

Table 25. Statistical comparisons of the monthly mean densities (N/m3 ) of entrained smelt larvae between di ssimi 1 ar and simil ar intakes that are "adjacent" 

to one another. Underlined densities are significantly higher (a = 0.05). 

January February Mlrch April Mly June July August September October Novefllber December 

Kewaunee vs. Point Beach 

04/18/75-10/31/75 

OOB .00046 .02027 .00169 .02555 .01206 .03186 .03551 

PD 0 0-- 0-- 0-- -:nu5!S" -:ntlIM -:nom 

Waukegan vs. Zion 

04/16/75-09/03/75 

CNL 0 .00053 .00100 0 0 0 

OOB 0 .03555 .00492 0 0 0 

Lakeside vs. Port Washington w OS/20/75-10/28/75 ~ PO 0 0 0 0 0 0 

CNL 0 0 .00026 .00149 .00298 0 

Lakeside vs. Oak Creek 

OS/20/75-10/29/75 

PO 0 0 0 0 0 0 

CNL 0 .00021 .00021 .01518 .00837 .00152 

Oak Creek vs. Port Washington 

04/17/75-10/28/75 

CNL 0 .00048 .00021 .00286 .01518 .00837 .00156 

CNL 0 0-- 0-- :llOMO -:-mrrn- ~ 0--

Mitchell vs. Stateline 

05/03/75-09/04/75 

PO .02996 0 .00117 .00365 .00012 

PD -:1mM5" 0 :oonor ~ 0--
Yell ow Perch 

The results of statistical comparisons for yellow perch impingement between intake types (Table 18) are highly affected by the disproportionate 

impingement density at the Pulliam plant (onshore canal intakes). Figure 8 

presents the annual perch impi ngement densiti es at each sampl ed intake and 

indicates that, if Pulliam is excluded, offshore open bay intakes and any type 

sited on the southeastern shore of Lake Michigan impinge the highest densities 

of yellow perch. Comparisons of "adjacent" plants (Table 26) indicate the OOB 

and canal intakes impinged more yellow perch/unit volume than do porous dike 

intakes, and that the canal intake at Waukegan impinged higher densities of 

perch than the OOB intake at Zion. No consistent differences were observed 

between the "adjacent" canal intakes or between the "adjacent" porous dike 

intakes. 

Yell ow perch eggs were not i dentifi ed at some and not found at other 

sampled intakes, making a statistical comparison difficult. The annual mean 

density of perch eggs at D. C. Cook was similar to that at Pulliam (Fig. 9) 

despite the order of magnitude difference between perch impingements at these 

plants, indicating that OOB intakes might entrain significantly higher densities, if inshore abundances were equal. Based on the very 1 imited data in 

Figure 10, it appears that canal intakes are at least as destructive of yellow 

perch larvae as are OOB intakes, if Pulliam is excluded. 

Effects of Flow and Geographic Location 

Generally, it is assumed that the numbers of fish impinged or entrained 

by water intakes are directly related to the water flow or quantity 

withdrawn. A "perfect" linear relationship between these variables (i .e., 

where all the variability in y is explained by the variability in x) would 

require homogeneous distribution of the fish species/life stage throughout the 

body of water, as well as no site-specific, intake-related differences in 

impingement/entrainment rates. It is clear from the preceeding analyses that 

nei ther of these requi rements are true for any of the three Lake Mi chi gan species included in this report. 

Since the sampling of power plant intakes was planned and executed in a 

site-specific manner, the available data do not provide adequate representation of the variables potentially affecting impingement and entrainment 

values: i.e., a stratified or hierarchal sampling design would be required to 

estimate the individual effects of intake type, location, fish abundance, and 

flow. Despite these apparent problems, we performed linear regressions (log 

observed impingement/entrainment vs. log observed flow) for each 

species/l ifestage to estimate the effects of flow and to determi ne the feasibility of predicting the effects of future water intakes. 

The effect of water intake flow on impingement of alewife is shown in 

Figure 11. A strong linear (log-log) relationship was found (P <0.0001) and 

the results indicate that 66% of the variability in impingement (R2 = 0.66) is 

associated with flow. It is apparent from this plot that four intakes 

impinged inordinately high numbers of alewife: Zion (1), Port Washington (8), 

Pulliam (5), and Michigan City (4). The aforementioned effects of canal 

intakes and western shore locations are substantiated. This indicates that a 

canal intake sited on the western shore of Lake Michigan or on Green Bay could 

40 
Table 26. Statistical comparisons of the monthly mean densities (N/1000 m3 ) of impinged yellow perch between di ssimi lar and similar intakes that are "adjacent" to one another. Underlined densities are significantly higher (a = 0.05). 

January February r.\Irch April r.\Iy June July August September October November December 

Kewaunee vs. Point Beach 

04/01/75-02/28/76 

OOB 0 .00009 .00034 .00014 .00054 .00086 .00040 .00053 .00029 .00050 .00017 

PO .00007 .00004 .00059 .00006 --:mmmr ~ .00027 .00028 .00020 -:-ommr .00021 

Waukegan vs. Zion 

05/12/75-12/31/75 

CNL .00005 0 .00009 .00027 .00108 .00113 .00003 .00050 

OOB 0 0 .00010 -:-ooo2lr -:-ommr ~ .00042 -:-mmtlD 

Lakeside vs. Port Washington 

03/07/75-02/06/76 

.j::o. PO 0 0 0 0 0 .00002 .00032 .00010 0 0 0 0 

....... CNL 0 .00054 .00086 .00113 .00040 .00054 .00078 .00044 .00018 .00007 .00046 .00020 

Lakesi de vs. Dak Creek 

03/07/75-02/06/76 

PO 0 0 0 0 0 .00002 .00032 .00010 0 0 0 0 

CNL .00052 .00039 .00219 .00107 .00020 .00010 .00411 .00039 .00021 0 .00027 .00105 

Bai lly vs. Mi chi gan City 

12/03/75-06/28/76 

PO .00200 .00020 .00068 .00029 0 .00029 .00109 

CNL 0-- .00156 .00201 .00346 .00631 .00188 .00178 

Oak Creek vs. Port Washington 

03/04/75-02/25/76 

CNL .00052 .00009 .00207 .00107 .00020 .00010 .00411 .00039 .00021 0 .00027 .00105 

Mitchell 

CNL vs. Statel ine 

U-- .00013 -:1lOO7T .00113 .00040 .00054 -:ummr .00044 .00018 .00007 .00046 ~ 

05/03/75-03/30/76 

PO .00040 .00003 .00052 0 .00024 .00307 .00437 .00028 0 .00008 .00080 

PO .00028 .00037 -:ucmrr .00027 .00097 .00419 .00288 .00037 .00031 .00005 -:1lOOll'f 
100'~-------------,----------__ ~ ______________ .-__________ ~ 

>-

f--

If) 

Z 

W 

o 

I-- 1O-3t=- z 

w 

:EO 

'-" Z 

"-:EO 

~ IO-~=-

x D. C. Cook 

• 

)( ZIon 

Kewaunee 

x Palisades 

X PullIam 

• 

X MichIgan CIty 

x Campbell x Oak Creek 

~ Port Washington 

Waukegan 

x Bailly 

~ Stateline 

• MItchell 

Big Rock ~ Point Beach 

x Lakeside 

10-5~----------__ ~ ______________ ~ ______________ ~ ____________ ~ 

OPEN BRY CRNAL POROUS DIKE 

Fig. 8. Mean annual densities of impinged yellow perch at 

each sampled intake (1975). Circles represent means for 

each intake type. 

1O- 11="""-------,--------,.-------,--------:J 

x Pulliam 

lO-2t=-

§:: x D. C. Cook • "-,!!. • ~ 10-3 ::- ~ 

If) 

z 

w 

0 

I--

Z 

~ lO-~1:- z 

~ 

a: 

a: 

I--

z 

w 

10-51:-

Port Washington, 

10-6 Palisades Campbell ·1 • 

OPEN BRY CRNRL POROUS DIKE 

Fig. 9. Mean annual densities of entrained yellow perch 

eggs at each sampled intake (1975). Circles represent 

means for each intake type. 

42 
8 

L:J 

Z 

"-

10-2~------r--------r------~-..---------' 

~ 10-4 ,,-

...... 

en 

z 

w 

o 

... 

z 

~ 10-5,,- z 

...... 

a: 

a:: 

... 

z 

w 

x D. C. Cook 

• 

x Pulliam 

• 

-

X Port Washington 

1O-71...-______ +lP:.!!a~hbJi.s_'!lad!£e~s ___ --+~C::llam!E.u·b2.!el.!.ILl ___ --'-______ .......J 

• + 

OPEN BRY CRNRL POROUS DIKE 

Fig. 10. Mean annual densities of entrained yellow perch 

larvae at each sampled intake (1975). Circles represent 

means for each intake type. 

&1 

&8 

~ 105 

UJ 

"-

'" UJ 

-' a: 

&4 

IN(A) = -39.259 + 2.555*lN(flow) 

.I 01~"7--'--'--...J......J...J....i.-+,-,-*",l..L.L--'--'--..L-!...L..W..1OL,;9--'--'---'--'...J....i..J..l!...1.0':'::IO--'---'-J..-L..J...LJo.J..JlO'11 

FLOW fM3J 

43 

Fig. 11. Relationship 

between total number of 

alewife impinged and 

total flow (1975). 
impinge ten times the number of alewife as another intake type sited elsewhere. 

The relationship between flow and entrainment of alewife eggs was not 

significant (P > 0.6)(Fig. 12). This indicates that the distribution of 

alewife eggs is more heterogeneous than that of adults and/or that intake type 

has a pronounced effect on egg entrainment. As previously mentioned, intakes 

on the southern shore of Lake Michigan (3, 11, 13, 12) entrain relatively high 

numbers of alewife eggs. Conversely, the numbers of entrained alewife larvae 

are related to flow (P <0.003) and 52% of the variability can be attributed to 

flow (Fig. 13). Again, intakes in the southern basin (e.g., 2, 3, 11,13,1, 

12) entrain the highest numbers of alewife larvae. 

Impi ngement of rai nbow smelt is di rect1y re1 ated to water flow on a 

1akewide basis, despite 10cationa1 differences in abundance (Fig. 14). The 

log-log regression was signific1nt (P = 0.0005) and indicated that 59% of the 

variability was due to flow (R = 0.59). Water intakes on the western shore 

impinged the highest numbers of smelt. Entrainment of smelt eggs and larvae 

were significantly related to variations in flow (Figs. 15 and 16, 

respectively). Forty-two percent of the variability in smelt eggs and 56% of 

the variability in smelt larvae were attributable to flow. Intakes on the 

southern shore entrained relatively large numbers of smelt eggs while southern 

and western intakes entrained large numbers of larvae. 

Impingement of yellow perch was significantly related to flow on a lakewide basis if the Pulliam intake (5) was excluded (Fig. 17). Intakes in Green 

Bay (5) and in the southern basin of Lake Michigan (2, 12, 3, 13, 1) impinged 

relatively high numbers of yellow perch. 

Figures 11-17 provide a measure of predictability of the expected 

impi ngement or entrainment losses associ ated wi th anti ci pated increases in 

water wi thdrawa 1 s. Sl i ghtly better predi cti ons coul d be obtained gi ven the 

intake design and location on Lake Michigan, but accurate predictions are not 

possible since the important effects of (l) spatial heterogeneity in abundance 

and (2) annual fluctuations in abundance are not quantified. 

DEVELOPMENT OF MATHEMATICAL MODELS 

The surpl us product; on model and dynami c pool model are two different 

mathematical models that are commonly applied for assessment of the impact of 

exploitation on fish populations. In this study these models are applied for 

assessment of entrai nment and impi ngement impacts. Impi ngement impact is 

comparab 1 e to the impact of a fi shery and the fi shery models can be app 1 i ed 

with little modification. Assessment of the impact of entrainment requires 

more substantial modification of the models.· 

Surplus Production Model 

In all populations, biomass is continually added by growth and recruitment and lost through mortality. Surplus production is the amount of biomass 

that can be removed from a popul ati on wi thout changi ng the popul at; on size: 

i.e., the biomass removed is replaced by recruitment and growth. In 

derivation of the surplus production model it is assumed that surplus 

production is some function of population size. Surplus production is assumed 

44 
\0 1 

\09t0 

w 

:'S 

a: 

a:: 

rZ 

w 

~ \OB~ 

'-' w 

W 

lL 

~ 

3: 

W 

-.J 

a: 

107 

106 

107 

I 

AS 

A9 

l,s.L 16 

1~~ 

lOB 

I I 

A3 

All 

,Al3 

AS 

,1,4 

. 

A9 

A 12 A2 

A1 

A6 

A10 

A7 

,I 

109 

FLOW (M3) 

A1 

I Al2 

/ A10 

; ... 6 

,. 8 .6.7 

LL 

\010 

LN(AL) = -75.535 + 4.467*LN(flow) 

1 0 3~-,-..J....~""""'1tl;U11....I....--'-.!....J....Ju..u.,;;--'-..J.....!....J....Ju..u.,"=,-,-..J.....!....J....J..u.u 

107 109 1010 lOll 

FLOW (M3) 

45 

-

1011 

Fig. 12. Relationship 

between total number of 

alewife eggs entrained 

and total flow (1975) . 

Fig. 13. Relationship 

between total number of 

alewife larvae entrained 

and total flow (1975). 
103 

102 

107 

.... 3 .... 12 

A.14 

.... 4 .... 13 

LN(S) = -38.4~5 + 2.314*LN(flow) 

.... 16 .... 9 

lOB 109 10 10 

FLOW 1M3) 

0 

!j;! 106 ,.;6 

a: .... 5 -/ a:: 

IZ 

UJ 

(f) 

L!J 

t.:J 

UJ 

I-

~ 105 

(f) 

.... 10 

LN(SE) • -65.024 + 3.912 x LN(flOW) 

1 0130·L;7'--.L.-I-'-~L:Iii~~t-'-""""'~O:09-L..-J.--'--'L..J..L..~1 O~IOO'---'-'-""""'l;-;;'O 11 

FLOW 1M3) 

46 

;w 

lOll 

Fi g. 14 . Relationship 

between total number of 

smelt impinged and total 

flow (1975) . 

Fig. 15. Relationship 

between total number of 

smelt eggs entrained and 

total flow (1975). 
10 7 

.t.l3 

~! 106 .7 

~f .2 

0 .1 w 

2'S 105 a: .12 a: 

lZ 

W 

W 

a: 

:> .s a: 

a: 

--' 

d 104 

:0:: 

(() 

IN(SL) = -63.883 + 3.881*LN(flow) 

102'~~~~~~~~~~~~~~~~~~~~ 

107 10 9 lO lD 1011 

FLOW (M3) 

.s 

.2 

.1 

... 4 

47 

Fig. 16. Relationship between 

total number of smelt larvae 

~ntrained and total flow (1975). 

Fig. 17. Relationship between 

total number of yellow perch 

impinged and total flow (1975). 
to be small at both high and low population sizes. The maximum surplus 

production occurs at some intermediate level of population size. 

In the surpl us producti on model the change in yi el d (bi omass of fi sh 

caught) with respect to time is assumed proportional to the production of 

biomass and fishing effort. If the natural change in biomass is described by the logistic equation, then the surplus production model is: 

dY _ dt - qEB 

dB - kB _ ~ B2 - qEB dt - B 00 

where: 

Y = yield in kg 

B = population biomass in kg 

k = population growth parameter 

Boo = environmental carrying capacity or population level without fishing E = fishing effort in standard units 

q = catchability coefficient 

t = time in years. 

Under equilibrium conditions, the relation between equilibrium yield and 

biomass is the parabola 

_ k 2 Ye - kB - B B 00 

where Ye is the annual equilibrium yield. The maximum sustainable yield, MSY, 

occurs at a bi omass 1 evel of Boo/2, so the MYS is:, 

MSY = k :~ _ t G~) 2 = 2:B~ _ k:~ = k:~ 

For each speci es the parameters of the surpl us producti on model were 

estimated by non-linear least squares using the approximation: 

Y (t) = Y(t + 1) - Y(t) = qE(t} J+ B(t)dt ~ qE(t) B(t + 1) + B(t) t 1 [ '1 

a t 2 .J 

where Ya is the annual yield. The solution to the logistiC surplus production 

model is: 

48 
where Bo is the estimate of biomass in 1960 obtained as l/q (1960 CPUE) and F 

is the lnstantaneous fishing mortality c'oefficient. . 

The surpl us producti on model can be modifi ed easily to model th-tl, impact of impingement. Let f· be the impingemen~ coefficient for the i water 

intake and Q; be the vo'ume flow for the it water intake; then the surplus 

production model can be written as: 

-: = kB - ~ B2 - qEB co 

n 

I i=1 

where the new terms are: 

n = number of water intakes 

f.Q.B 

1 1 

Ii = impingement at water intake i at time t 

fi = impingement coefficient at water intake i 

Q; = volume flow at water intake i at time t. 

To apply the surpl us production model for assessment of entrai nment, 

equations must be developed for egg production and for larval production; then 

larval production must be related to the biomass of the standing stock. The 

number of eggs produced by the population, G, is: 

B G = 2" EUB 

where EUB is the number of eggs produced per unit of female biomass and G is 

the number of eggs produced by the popul at; on. The rate of loss of eggs through entrainment at water intake i is: 

where G1 is the number of eggs entrained at time t and Pi is the egg entrainment coefficient at water intake i. Substitution from above gives the 

equation: 

Assuming that, in the long run, the population produces enough eggs to just replace itself, then 

49 

----.-----
2 dG ' 

EUB dt' 

where (dB/dt}e is the rate of biomass loss as a result of egg entrainment. 

The amount of biomass produced is a function of the number of eggs produced. 

The impact of entrainment on egg is equivalent to a reduction in egg 

production by the population. The rate of biomass loss resulting from egg 

entrainment, (dB/dt}e' is 

Now the impact of larval entrainment on biomass production will be determined. The number of larvae produced by G eggs is: 

L = (1 - <I>}G 

where L is the number of larvae produced from G eggs and <l> is the mortality 

from the egg stage to the larval stage. The relation between adult biomass 

and the number of "larvae produced is given by the equation 

L = (1 - <1» ~ B. 

Differentiation of this equation with respect to time gives 

dL = (1 _ <l» E UB dB 

dt 2 dt 

anR the rate of change in biomass resulting from entrainment of larvae at the 

it water intake, (dB/dt)" is 

(

dB) _ dL I Idt 

dt 1 - (1 - </» ~ 

where dL'/dt is the rate of larval entrainment at the water intake. The rate 

of larval entrainment at water intake i can be modeled with the equation 

where hi is the larval entrainment coefficient at water intake i. Combination 

of the above equations for larval entrainment gives the rate of biomass change 

resulting from larval entrainment at water intake i as 

50 

_ UWQb ~ ¢ $-
Combi ni ng the above equati ons for egg and 1 a rva 1 entra i nment gi ves the 

following surplus production model for assessment of entrainment impact: 

M = qEB 

dL ' n 

dt - I p.Q.B 

i=1 1 1 

dG ' n 

dt - I hi Qi B 

i=1 

: = kB _ ~ B2 n n - qEB - I p.Q.B - I hi Qi B. B 1 1 00 i=1 i=1 

Combining the model for entrainment and impingement impact gives the model 

dY M = qEB 

dI n 

M= I fi Qi B 

i=1 

dG ' n 

dt - I p.Q.B i=1 1 1 

dL ' n 

dt = L hi Q; B 

i=1 

dB _ ~ B2 n n n 

dt - kB - qEB - L f.Q.B L P; Q; B - I h; Qi B. B ; =1 1 1 00 i=1 ;=1 

This model was applied to study the combined impacts of impingement and 

entrainment on standing stocks and maximum sustainable yields of alewife, 

perch, and smelt. 

Dynami c Pool Model 

The dynamic pool model [28] provides a more complete and detailed 

description of the dynamics of a population than does the surplus production 

51 

----------------
model [29]. The dynamic pool model is a reductionistic model in which the 

yield from a fishery is broken into its components: growth, reproduction, and 

mortality. Each of these components is modeled separately, in as great a 

detail as necessary, and then the components are brought together into a model 

for yield. 

The derivation of the dynamic pool model begins with the identity 

re 1 ati ng the bi omass of a cohort to the number of i ndi vi dua 1 s and average 

individual weight. The biomass of a cohort at age x, B(x), is the product of 

the number of individuals of age x, N(x), and the average weight of an 

individual of age x, W(x): 

B(x) = N(x)"W(x). 

Differentiation of this equation gives the change in biomass with respect to 

age as 

dB(x) = N(x) dW(x) + W(x) dN(x) dx dx dx 

The first term on the right relates to production and the second term to the 

loss of biomass by mortality. Yield to a fishery equals the loss due to 

fishing: 

dY _ -W(x) ('dN(X») dx - dx F 

where (dN(x)/dx)F is fishing mortality. It is usually assumed that 

(

dN(X») = -FN(x) dx F ' 

where F is the instantaneous fishing mortality coefficient and the yield 

equation then becomes 

~ = F N(x) W(X). 

To apply this model, relations for W(X) and N(x) as functions of age must be 

developed. Assume that fish are recruited into the exploited stock at age xG; 

then if mortality follows the exponential model, change in cohort size 1S 

given by the equations: 

dN _ dt - -(F + M)N, x > Xc • 

52 

$, " 
Solution of these equations gives the mortality equation 

where: 

M = instantaneous natural mortality coefficient 

Xc = age at entry to fishery 

xr = age at recruitment 

R = number of recruits. 

To model weight as a function of age, it is usual to begin with an 

equation for length as a function of age. Growth in length is asymptotic and 

can usually be described accurately by the equation: 

) ( -K(x - x )) t(x = t 1 - e 0 eo 

where: 

t(x) = length at age x 

teo = asymptotic length 

K = growth constant 

Xo = age when length equals zero (assumed to be zero). 

The relation between length and weight is accurately described by the 

parabolic growth equation 

W(x) = a t(x)b 

where a and b are constants. For simpl icity it will be assumed that b = 3. 

Substitution of the equation for length as a function of age into the lengthweight equation gives the equation for growth in weight as 

where Weo = asymptotic individual weight. This is von Bertalanffy's growth equation [9]. 

Combining the above results for mortality and growth gives the yield 

equati on: 

The solution of the equation is 

53 

------~-- ----< ---<---- ---
where: Uo = 1, U1 = -3, U2 = 3, and U3 = -1 (integration constants). 

Modification of the dynamic pool model for assessment of impingement 

impact is straightforward. The rate of impingement with respect to age (time) 

is: 

The mortality equation modified to include the impact of n water intakes is 

N(x) 

where the new term is: xI = age when fish first become vulnerable to impingement. The biomass of a cohort subject to impingement loss is 

3 

L j=o n F + M + L f.Q. + jK i =1 1 1 

and the yield from the fishery under equilibrium conditions is 

Ye = FB. 

To apply the above equations the number of recrui ts must be determi ned. 

Application of the catch equation, 

~ = F N(x), 

(where Cis the annual catch from the fi shery) together with the mortal i ty 

equation gives: 

54 
n 

(M + F + ~ f.Q.)ce(M + I f;Q;)(xc - xI) 

L 1 1 i =1 i =1 R = ------------------~------------------ F 

Additional modifications of the dynamic pool model are necessary to apply 

the model for assessment of entrainment. The number of eggs produced annually 

in a steady state is: 

B G = EUB 2" • 

These eggs are subject to natural and entrainment mortality so an equation for 

change in the numbers of eggs is: 

where: 

M1 = natural mortality coefficient for egg stage. 

The number of larvae produced by an initial number of eggs, G(o), is 

n 

L(o) = G(0)e-(M1 + i~l PiQi)~t1 

where: 

L(o) = number of larvae produced by a cohort 

G(o} = initial number of eggs produced by a cohort ~t1 = duration of time from spawning to larval stage (after yolk sac has 

been adsorbed). 

Larvae are subject to natural mortality and entrainment mortality; thus, 

the equation for change in the number of larvae is: 

dL _ dx - -(M2 + 

where: 

n 

I h.Q.)L i =1 1 1 

M2 = larval mortality coefficient. 

Combining the above equations for egg production, egg mortality, and larval 

mortality gives the following equation for the number of recruits: 

55 

.~~~~~~,-------~--- - ---------.-----.. --~~~ 
where ~t2 is the duration of time from first entry into the larval stage to 

the young-of-year stage. 

The impact of entrainment on standing stock and yield will be a result of 

its impact on recruitment. 

ESTIMATION OF BIOLOGICAL AND FISHING PARAMETERS 

Surplus Production Model 

For the surplus production model the catchability coefficient, q, 

population growth parameter, k, and carrying capacity, B"", were estimated by 

non-linear least squares using the commercial catch and effort data. Lake 

Michigan has been divided into 16 fishery statistical districts (Fig. 1) and 

data on catch and effort are obtained annually for each district. In this 

study data for the years 1960 to 1977 were appl ied for estimation of model 

parameters. 

For each speci es the parameters of the surpl us producti on model were 

estimated by non-linear least squares using the approximation 

Ya(t) = Y(t + 1) - Y(t) = qE(t) 

t+1 r ] J B(t)dt ~ qE(t)I·B(t + 1)2+ B(t) 

t L 

and the solution to the logistic surplus production model is: 

r k [1 k] -(k - F)tj-l B(t) = B",,{k - F} + L~ - B",,{k - F} e ... ... 

where Bo is the estimate of biomass in 1960 obtained as 1/q (1960 CPUE). 

Alewife 

The major fishing methods applied for alewife were trawls and pound 

nets. Pound nets are used more wi dely than trawl s; therefore, total effort 

was expressed in terms of pound nets. Tota 1 effort in terms of a standard 

gear was calculated as 

total catch 

total effort = CPUE with standard gear 

where CPUE = catch per unit effort. The total catch and effort data for 

alewife in Lake Michigan are listed in Table 27. For alewife the model 

parameters are: 

56 
q = 0.00001 

k = 0.30 

B~ = 400,000,000 kg. 

The fit of the observed yields to the predicted yields is good in recent years 

(Fig. 18), and for 1975 the observed yield is close to the predicted yield. 

In 1963 the model predicts a much higher yield than was observed and in 1967 

the model predicts a much lower yield than was observed. From 1968 to 1977 

the predi cti ons are good except for 1973 when the predi cti on was somewhat 

high. Substantial changes have occurred in the fishery since 1960 with large 

variations in population size and massive die-offs. 

The maximum sustainable yield occurs at a biomass level of about 

200,000,000 kg and is about 30,000,000 kg (Fig. 19). The maximum observed 

catch of 21,959,080 kg occurred in 1977. The alewife population does not 

appear to be over-exploited by the fishery but the level of exploitation is 

substantial .. 

Table 27. Total catch (kg), pound Table 28. Total catch (kg), trap 

net effort (number of lifts), and net effort (number of lifts), and 

catch per unit of effort for alewife catch per unit of effort for yellow in Lake Michigan, 1960-1977. perch in Lake Michigan, 1960-1977. 

Year Catch Effort CPUE Year Catch Effort CPUE 

1960 1057103 2621 403.26 1960 1489562 57444 25.93 

1961 1449346 2327 622.71 1961 2574813 98958 26.02 

1962 3456625 8501 406.58 1962 2039568 59269 34.41 

1963 2448165 24582 99.59 1963 2210172 50186 44.04 

1964 5326641 11546 461. 32 1964 2646878 91459 28.94 

1965 6353358 7425 855.60 1965 695885 49878 13.95 

1966 13155789 12118 1085.57 1966 406440 30426 13.36 

1967 19054064 16742 1138.06 1967 573967 27501 20.87 

1968 12285364 11462 1071. 77 1968 235669 15364 15.34 

1969 13330230 10050 1326.32 1969 291719 15719 18.56 

1970 15114488 10203 1481.28 1970 313820 17628 17.80 

1971 13450181 7599 1769.92 1971 338270 18324 18.46 

1972 14076502 7767 1812.34 1972 465686 20050 23.23 

1973 16584780 11872 1396.85 1973 339997 20372 16.69 

1974 20663696 10131 2039.52 1974 587902 32909 17.86 

1975 15961428 7730 2064.81 1975 344354 22946 15.01 

1976 17786288 7918 2246.07 1976 387206 31864 12.15 

1977 21959808 7931 2768.55 1977 439831 44057 9.98 

Yellow Perch 

The major fishing methods for yellow perch were 2" gill nets, shallowtrap nets, fyke nets, and hoop nets. Shallow-trap nets are the most widely 

used gear and were selected as the standard gear. The total catch and effort 

data for Lake Michigan are listed in Table 28. 

For yellow perch the parameter val ues appear to have changed 

substanti ally between 1960 and 1977. The estimates for 1960 to 1977 (l east 

57 
20 

Iii' 8 15 

x 

l!l 

15 

Cl 

;;]10 

>-

5 

_7 

1\ 

1\ 

1\ 

I \ 

I \ 

I \ 

I \ 

\ 

YEflR 

OBSERVED 

- - - - - - PREDICTED 

Fig. 18. Observed yields and yields predicted by surplus 

production model for alewife in Lake Michigan. 

100 200 

BIOMASS (KG X 106) 

300 I!OO 

Fig. 19. Stock production curves for alewife in Lake 

Michigan at 5 different levels of water withdrawal considering only the impact of impingement (f - 0.1071 x 10- 12 ); 

Vo = 0.0 m3 /yr; VI = 1.0 x 10 10 m3/yr; V2 = 5.0 x 1010 m3 /yr; 

V3 = 10.0 x 1010 m3/yr; V4 = 25.0 x 10 10 rn 3/yr. 

58 
squares) of the population parameters are: 

k = 0.01 B~ = 80,000,000 kg 

q = 0.0000001. 

But these estimates resul tin a substanti al overestimate of recent yi el ds. 

Better estimates of yield from 1965 to 1977 are obtained with the parameters: 

k = 0.20 B~ = 14,837,363 kg 

q = 0.0000014. 

Observed yields and predicted yields using these parameters appear in Figure 

20. It appears that the carrying capacity of Lake Michigan for yellow perch 

decreased substantially between 1960 and 1977. Yields have decreased from 

more than 2,500,000 kg to less than 500,000 kg. The model accurately predicts 

yields from 1965 to 1977. At present the maximum sustainable yield of about 

741,869 kg occurs at a biomass of about 7,000,000 kg. A further analysis of 

the data is necessary to determine the degree to which over-fishing is related 

to the observed decrease in commercial catch. 

Smelt 

The major commercial fishing methods for smelt are 1" gill nets and pound 

nets. Pound nets were selected as the standard gear. The total catch and 

effort data for smelt in Lake Michigan are listed in Table 29. 

Table 29. Total catch (kg), pound 

net effort (lifts), and catch per 

unit of effort for smelt in Lake 

Michigan, 1960-1977. 

Year Catch Effort CPUE 

1960 1479932 4841 305.66 

1961 715538 2620 273.02 

1962 702333 2186 321.26 

1963 526710 2045 257.47 

1964 404620 959 421. 91 

1965 419599 1124 373.27 

1966 503533 1087 462.97 

1967 554953 812 683.44 

1968 811191 944 859.06 

1969 1125453 641 1753.72 

1970 923976 482 1914.06 

1971 588707 369 1591.14 

1972 312880 177 1765.69 

1973 393846 336 1171.43 

1974 774028 341 2265.82 

1975 527318 208 2528.01 

1976 983727 303 3237.12 

1977 331362 300 1101.38 

59 

----------- ----
o 

...J 

w 

~ 

>-

I 

I 

I 

I 

\ 

\ , 

\ , 

" \ 

, I 

, I 

, I 

I 

I 

YFAR 

OBSERVED 

- - - - - - PREDICTED 

Fig. 20. Observed yields and yields predicted by surplus 

production model for yellow perch in Lake Michigan. 

1.5 

/' / \ 

\ 

0.5 

1~55 1960 

\ , \ I 

" 

1965 

YEAR 

1970 

OBSERVED - - - - - - PREDICTED 

1975 1980 

Fig. 21. Observed yields and yields predicted by surplus 

production model for smelt in Lake Michigan. 

60 
For smelt the estimates of the model parameters are: 

q = 0.0001 

k = 0.50 

Bm = 20,000,000 kg. 

Again, it is clear that dramatic changes have occurred in abundance (Fig. 

21). The model fits well from about 1969 to 1977 but for earl ier years the 

model predicts much higher yields than were observed. 

The smelt population in Lake Michigan is not heavily exploited by the 

commercial fishery. The maximum sustainable yield is 2,500,000 kg and the 

observed yield has seldom been more than 1,000,000 kg. The size of the smelt 

population also fluctuated widely between 1960 and 1977. To accurately assess 

the impact of fishing a more detailed analysis is necessary. 

Dynamic Pool Model 

Parameter estimates for the dynami c pool model were obtai ned ei ther 

directly from the literature or were calculated from data in the literature. 

Al ewife 

T~bl: 30.[3B]owth of alewife in Lake 

Mlchlgan. 

Age 

1 

2 

3 

4 

5 

6 

7 

Length (mm) 

97 

142 

163 

175 

183 

195 

204 

Weight (gm) 

7.24 

22.90 

34.67 

42.66 

48.98 

58.88 

67.61 

The length, weight, and age data for alewife in Table 30 were reported by 

Brown [30] for female alewife in 1964. The parameters for growth in terms of 

length were found by fitting the equation 

t(x + 1) = t (1 - K) + Kt(x) m 

by least squares, where: 

t(x + 1) = length at age x + 1 (in mm). 

The estimates of the growth parameters are K = 0.31 and tm = 224. The 

relation between length and weight for alewife is given by the parabolic equation [30] 

61 
10910 W = -5.12 + 3.01 10910£ 

and the von Bertalanffy growth equation is 

W{x) = 0.11642 {l _ e-0•31 x)3 

where weight is measured in kg. The asymptotic weight is W~ = 0.11642 kg. 

To obtain. the number of eggs per unit of biomass a relation between 

length and egg production [31] (Table 31) was applied with estimates of 

average length (170 mm) and average weight (39.23 g). The number of eggs 

produced per kg of female was estimated as EUB = 368,000 (14,436 eggs per 

female). 

The total mortal i ty rate for al ewi fe (Tabl e 32) was estimated from age 

structure data reported by Edsall et al. [26]. The total instantaneous 

mortality rate estimated by least squares is 0.50. Using the estimate of q 

obtained with the surplus production model and the observed fishing effort, 

the fishing mortality was estimated as F = qE = 0.06. The egg mortality and 

larval mortality coefficients were obtained by calibration of the observed 

yield with the calculated yield. The parameter estimates for alewife are 

listed in Table 33. 

Ye 11 ow Perch 

Much of the biological data for ·yellow perch in Lake Michigan is 

summarized by Brazo, Tack, and Liston [32]. From the growth data in Table 34 

the growth parameters were estimated as £~ = 300 and K = 0.45. The 1 engthweight relation used was 

which gives the asymptotic weight W~ = 1-" kg. Length is in millimeters and 

weight is in grams. 

A total mortality coefficient of 0.36 was estimated from the data in 

Table 35. The number of eggs produced per unit of biomass was calculated from 

the equation 

where t is total length in mm. The average length was taken as 200 mm which 

gives 17,309 eggs per female on the average and 65,316 eggs per kg of 

female. The parameter estimates are summarized in Table 36. 

62 
Table 31. Fecundity of alewtSI]in Green 

Bay as a function of length. 

Age Number 

2 18 

3 15 

4 2 

Mean Length 

160 

176 

192 

Number Eggs 

11147 

16138 

22407 

Table 32. Age stf~~jure of alewife 

in lake Michigan. 

Age 

1 

2 

3 

4 

5 

6 

7-8 

Relative Number 

1000 

600 

300 

120 

36 

13 

3 

Table 33. Estimates of alewife parameters for dynamic pool model. 

Parameter 

Asymptotic weight 

Average wei ght 

Catchable age 

Impingeable age 

Age when length is zero 

Instantaneous fishing mortality coefficient 

Instantaneous natural mortality coefficient 

Age at maturity 

Growth parameter 

Eggs per unit biomass 

Egg mortality coefficient 

larval mortality coefficient 

Duration of egg stage 

Duration of larval stage 

Table 34. Standard length (nm) e~2~el1ow perch 

at the end of each year of life. 

Ludington Green Bay N.W. Lake 

Age '? r! '? cf '? cf 

2 162 159 99 99 96 

3 206 182 137 130 128 

4 225 215 173 159 154 

5 252 235 197 185 183 

6 291 247 228 211 212 

7 313 252 251 227 

63 

Symbol 

Woo 

Wavg 

Xc 

xI 

Xo 

F 

M 

Xmat 

K 

EUB 

M1 

~~1 llt2 

Tabel 35. 

Estimate 

0.1164 

0.0392 

2.0 

1.0 

0.0 

0.06 

0.50 

2.0 

0.30 

368,000.0 

11.51 

5.50 

0.10 

1.00 

Age structure of yellow per~h POpu~~~jon in lake Michigan at 

Ludlngton. 

Age Relative Number 

1 12 

2 65 

3 619 

4 423 

5 272 

6 138 

7 13 

~~- -----
Smelt 

Table 36. Estimates of yellow perch parameters for dynamic pool model. 

Parameter 

Asymptotic weight 

Average weight Catchable age 

Impingeable age Age when length is zero 

Instantaneous fishing mortality coefficient 

Instantaneous natural mortality coefficient 

Age at maturi ty Growth parameter 

Eggs per unit biomass 

Egg mortality coefficient 

Larval mortality coefficient 

Duration of egg stage Duration of larval stage 

Symbol Estimate 

1.0 

0.265 

3.0 

1.0 

0.0 

0.06 

0.30 

2.00 

0.45 

65316.0 

11.51 

5.50 

0.10 

1.00 

Much of the available information on smelt was published by Bailey [33]. Application of the same methods used for alewife and yellow perch gives 

the parameter estimates summarized in Table 37. 

Table 37. Estimates of smelt parameters for dyanmic pool model. 

Parameter 

Asymptotic weight 

Average weight Catchable age 

Impingeable age Age when length is zero 

Instantaneous fishing mortality coefficient 

Instantaneous natural mortality coefficient 

Age at maturity Growth constant 

Eggs per unit biomass 

Mortality coefficient for eggs 

Mortality coefficient for larvae 

Duration of egg stage 

Duration of larval stage 

Symbol 

Woo 

Wavg 

Xc 

XI 

Xo 

F 

M 

Xmat 

K 

EUB 

M1 

~t1 lIt2 

ESTIMATION OF POWER PLANT-RELATED PARAMETERS 

Surplus Production Model 

Estimate 

0.03 

0.0140 

2.0 

1.0 

0.0 

0.03 

0.40 

2.00 

0.56 

107337.0 

11.51 

5.50 

0.10 

1.00 

In the surplus production model impingement at the ith water intake is 

modeled as: 

64 
dI. 1 _ 

At - f. Q. B f:,.) 1 1 ,.,. where: 

Ii = number of fish impinged at water intake i at time t 

B = population biomass estimated from surplus production model. 

The impingement coefficient can be estimated as 

Annual biomass impinged Ltdi) and volume flow (Qi) were estimated from plant data. The biomass of the population in the lake in 1975 was calculated from 

the 1975 commerci al catch and effort data and the catchabil ity parameter which 

was estimated from the surplus production model using the equation: 

B = ~ (1975 CPUE). 

Entrainment of eggs and larvae were modeled as: 

and 

Applying the same approach as above for impingement, the following equations 

can be obtained for the egg and larval entrainment coefficients: 

and 

where: 

~Gi = number of eggs entrained annually at water intake i ~Li = number of larvae entrained annually at water intake i. 

The number of eggs produced by the population was estimated as: 

B G = EUB- 2" • 

65 
The number of larvae produced was calculated using the equation 

n 

L = (1 - M1 - I PiQi}G i=1 

where M1 is the natural mortality between the egg and larval stages. calculations it was assumed that M1 = 0.99. 

Al ewi fe 

In all 

For alewife the catchability coefficient was estimated as q = 0.00001 and 

the catch per unit of effort in 1975 was 2064. The biomass in the lake in 

1975 is estimated as: 

8 = 206,400,000 kg. 

The estimates of the proportion impinged and the impingement coefficients are 

listed in Table 81. (Appendix 8). The proportions of eggs and larvae 

entrained and the egg and larval entrainment coefficients are listed in Tables 

82. and 83., respectively. 

Yellow Perch 

The least squares estimate of the catchability coefficient for yellow 

perch is 0.0000001 but this estimate results in overestimates of catches from 

the late 1960's into the 1970's. A better fit of predicted yields to observed 

yields for recent years is obtained with q = 0.0000014. The catch per unit of 

effort in 1975 was 15 which gives the 1975 biomass as: 

1 8 = 0.0000014 15 = 10,714,285 kg. 

The estimates of the proportions impinged and the impingement coefficients are 

listed in Table 84. The proportions of eggs and larvae entrained and the egg 

and larval entrainment coefficients are listed in Tables 85. and 86., 

respectively. 

Smelt 

For smelt in Lake Michigan the catchability coefficient was estimated as 

q = 0.0001 and the catch per unit of effort in 1975 was 2528 giving the 1975 

biomass in the lake as 

1 8 = 0.0001 2528 = 25,280,000 kg. 

The estimates of the proportion of smelt impinged and the impingement 

coefficients are listed in Table 87. The proportions of eggs and larvae 

entrained and the egg and larval entrainment coefficients are listed in Tables 

66 

_ A Q 
RH. and B9., respectively. 

Dynamic Pool Model 

In the dynamic pool model impingement at the ;th water intake was modeled 

as: 

The impingement coefficients were estimated as: 

where Ali is the biomass impinged annually at water intake i. Biomass of the 

population in the lake was estimated using the equation 

and the number of recruits was estimated as 

where C is the catch (in numbers) from the fishery. 

Entrainment of eggs and larvae was modeled u~ing the equations 

and the entrainment coefficients were estimated as: 

AG. _ 1 

Pi - Q

i G 

AL. 

h - 1 i - Q;[ . 1 

The number of eggs produced by the population was estimated as: 

67 

~~~~~~------~~- ---_. -------
G - EUB - -2-

00 

f B(x)dx 

xm 

where xm is the age at maturi ty and EUB is the number of eggs produced per unit of biomass. 

The number of larvae produced was calculated using the equation 

and the number of recruits produced by these larvae was calculated as 

n n 

R = Ge-(M1 + I Pl·Ql·)~t1 - (M2 + I h.Q.)~t2 i=l i=l 1 1 • 

All of the terms in the above equations have been described previously. A 

summary of the terms can be found in the glossary. 

Alewife 

The yield of alewife in 1975 was 15,961,428 kg (Table 27) and the number 

of alewife in the catch was estimated as 406,870,000. The estimate of the 

biomass of the population in the lake obtained from the parameters listed in 

Table 33 is 237,401,824 kg. The estimates of the proportions impinged and the 

impingement coefficients are listed in Table B10. The proportions of eggs and 

larvae entrained and the egg and larval entrainment coefficients are listed in 

Tables B11. and B12., respectively. 

Yell ow Perch 

The yield of yellow perch in 1975 was 344,354 kg (Table 28) and the catch 

was estimated as 1,299,449 perch. The estimate of the biomass of the 

population in the lake obtained from the parameters listed in Table 36 is 

15,339,617 kg. The estimates of the proportions impinged and the impingement coefficients are listed in Table B13. The proportions of eggs and larvae 

entrained and the egg and larval entrainment coefficients are listed in Table 

B14. and B15., respectively. 

Smelt 

The yield in 1975 was 527,318 kg and the number of smelt in the catch was 

estimated as 37,665,712. The estimate of the biomass of the population in the 

lake obtained from the parameters listed in Table 37 is 24,697,856 kg. The 

estimates of the proportions impinged and the impingement coefficients are 

listed in Table B16. The proportions of eggs and larvae entrained and the egg 

and larval entrainment coefficients are listed in Tables B17. and B18., 

respectively. 

68 
SIMULATION OF IMPINGEMENT AND ENTRAINMENT IMPACTS 

Both the dynamic pool model and the surplus production model were applied 

to simulate the impact of water withdrawal on the standing stocks and yields 

to the fi shery. The separate resul ts obtai ned wi th these two model s were 

similar; therefore, only the results for the surplus production model are 

reported. The impact of impingement was slightly less with the dynamic pool 

model because recruitment was assumed to be constant. In addi ti on, the 

combined impacts of entrainment and impingement are difficult to model with 

the dynamic pool model. In these respects, the surplus production model is 

somewhat superior to the dynamic pool model. 

Under equilibrium conditions where dB/dt = 0, the biomass equation of the 

surplus production model that includes terms for impingement becomes 

n 

kB -}- B2 - qEB - I fiQiB = 0 

co i=l 

and the population biomass as a function of volume flow can be written as 

n 

B f I Qi 00 i=l 

k 

B (k - qE) B = _CO_--r:-__ 

k 

- where f is an average impingement coefficient for the water intakes. This 

equati on predi cts ali near decrease in the bi omass of the standi ng stock as 

the volume flow is increased. 

Under equilibrium conditions (dB/dt = 0) the equilibrium yield from the 

population is given by the equation 

k 2 Y = kB - -- B - e B co 

The relation between equilibrium yield and biomass is a parabola. Application 

of the equation dY/dt = qEB shows that equilibrium yield also is a function of 

fishing effort, i.e., 

n B q2 co 2 I fiQi)E--r- E . i=l 

Thus, the relation between equilibrium yield and fishing effort also is a 

parabola. The maximum sustainable yield, MSY, occurs at a biomass level of 

Boo/2, and is given by the equation 

69 
kB rB n 

MSY = 4<» - t L Qi i=l 

- where f is the average impingement coefficient. The maximum sustainable yield 

decreases linearly as the volume flow increases. With zero volume flow the 

MSY is given by kB<»/4. 

Equati ons simi 1 ar to those above were appl i ed to simul ate the impact of 

larval and egg entrainment on the size of the standing stock and on the 

maximum sustainable yield. For entrainment the equations are: 

B (k - qE) (j) + fi}B n 

B = <» <» 

k k L Qi i =1 

kB B (p + ti) n 

MSY <» <» 

=4- L Q. 2 i=l 1 

- where p and h are the average egg and larval entrainment coefficients. To 

simulate the combined impact of entrainment and impingement the following two 

equations were applied: 

B (k - qE) (T+ p + fi}B n 

B <» <» 

= L Q. k k i =1 1 

kB B (r + p + h) n 

MSY <» <» L Qi = ~ . - 2 i=l 

Alewife 

The impact of water withdrawal appears to be largest on alewife so the 

results for alewife will be given in greater detail than those for smelt and 

yellow perch. The equilibrium stock production curve for alewife under five 

different rates of water withdrawal is shown in Fig. 19. Only the impact of 

impingement is modeled in this figure. Increasing the volume of withdrawal 

decreases the carrying capacity, the biomass level at which the maximum 

sustainable yield occurs, and the maximum sustainable yield. The line drawn 

through the maxima of the stock production curves is: 

kB rB <» <» 

MSY = """"4 - -Z 

n 

L Qi' i=l 

70 
The total design volume flow of all water intakes on Lake Michigan is 

about 4.8 x 1010 m3 per year. This level of flow results in slight decreases 

in the carrying capacity and MSY. Substantial increases in the volume of flow 

are necessary to cause a 1 arge impact on yi el d and standi ng stock. The 

impacts of entrainment, impingement, and the combined impacts of entrainment 

and impingement on alewife are summarized in Figs. 22 to 27. 

The highest impingement coefficient observed is 0.4331 x 10- 12 and the 

average impingement coefficient is 0.1071 x 10- 12 . The relation between 

standing stock biomass and volume flow for these impingement coefficients are: 

B = 279,266,660 - 0.0001428Q, f = 0.1071 X 10- 12 

B = 279,266,660 - 0.0005775Q, f = 0.4331 X 10- 12 • 

Biomass of the standing stock decreases slowly as the volume withdrawn 

increases (Fig. 22). At a volume flow of 4.8 x 10 10 m3/yr (full capacity flow 

at all water intakes) the total lakewide impingement u.n of alewife was 

estimated to be 2.1 x 106 kg (Table 6). Based on the 1975 biomass estimate of 

206,400,000 kg, the proportion· of the standing stock impinged (~I/B1975) is 

0.0102 (or 1.02%). The proportion reduction in the standing stock (Flg. 22) 

is calculated from the equation: 

(rB /k) co Q, 

where B~ = biomass with no water withdrawal. Assuming the average impingement coefficlent and a flow of 4.8 x 1010 m3/yr, the reduction in standing stock of 

alewife was 0.0245 (2.45%). The reduction in the standing stock is greater 

than the proportion of the stock impingen because the surplus production model 

assumes that the growth rate of the popul ati on is a functi on of popul ati on 

size. Impingement reduces the biomass in the lake until a level is reached 

where the rate of impingement is balanced by the increased growth rate of the 

stock. 

The impact of impingement on the yield to the fishery also is not 

large. The relation between the maximum sustainable yield and volume flow is 

given by the equations: 

- MSY = 30,000,000 - 0.00002142Q, f = 0.1071 X 10- 12 

MSY = 30,000,000 - 0.00008662Q, f = 0.4331 X 10- 12 • 

The maximum sustainable yield decreases slowly as volume flow increases (Fig. 

23). Applying the average impingement coefficient the proportion reduction in 

maximum sustainable yield is 0.034 (3.4%) at a volume flow of 4.8 x 1010 

m3/yr. The impact on yield is greater than the impact on standing stock. 

The maximum egg and larval entrainment coefficients are 0.1712 x 10- 12 

and 0.1743 x 10- 14 and the average values are 0.1756 x 10- 13 and 0.2236 x 

10-15 • The relation between biomass of the standing stock and volume flow for 

entrainment are: 

B = 279,266,660 - 0.0002306Q, p = 0.1712 X 10-12, h = 0.1743 X 10-1~ 

71 

- ----~-----------
29 

28 No water withdrawal ----------------------------------------------------

27 

26 

~ ~ -------

(f ) 0.1071 x 10-

~ 

12 -----__ 1 

avg 

.... 

<.) 

~ 25 ----~~ x 

L'l 

~ 2ll 

U1 

V1 

~ 23 0 

CD 

22 

21 

20 

19 

0 2 II 6 8 10 

VOLUME FLOW (M3 X 1010) 

Fig. 22. Impingement impact of increased water withdrawal 

on biomass of alewife in Lake Michigan (1975). Arrow indicates total design .flow for all water intakes in 1975. 

31r----r---,r---.----,----,---~----~--~----~--~ 

No water withdrawal ---------------------------------------------------

29 

----------

27 

iiJ 

;:: 25 

x 

L'l 

~ 

>- 23 U1 

:>: 

21 

19 

17 

0 2 8 10 

VOLUME FLOW (M3 X 1010) 

Fig. 23. Impingement impact of increased water withdrawal 

on maximum sustainable yield (MSY) of alewife in Lake 

Michigan (1975). Arrow indicates total design flow for all 

water intakes in 1975. 

72 

" ; ;44& os" 
I. 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

29 

28 

27 

26 

eo 

- 25 x 

~ 

~ 2LJ 

(f) 

(f) 

~ 23 0 

co 

22 

21 

20 

19 

0 2 

No water withdrawal 

-12 (Pmaxl 0.1712 x 10 

+ (h 1 0.1743 x 10- 14 

max 

LJ 6 

(p 1 0.1756 x 10- 13 

avg 

-15 + (haVg1 0.2236 x 10 

--------

8 

VOLUME FLOW (M3 X 1010) 

10 

Fig. 24. Entrainment impacts of increased water withdrawal 

on biomass of alewife in Lake Michigan (1975). Arrow indicates total design flow for all water intakes in 1975. 

31,----,----,-----,----,----,----,-----,----,----,----, 

,,9 

27 

~ 25 

x 

~ 

~ 

)- 23 (f) 

:>: 

21 

19 

No water wlthdrawal 

------------- (Pma) 

+ (hmaxl 0.1743 x 10- 14 

-13 (p aVg1 0.1756 x 10 

+ (h 1 0.2236 x 10- 15 

avg 

1~~--~----~2----~--~---~~--~~--~----8~---~---~10 

VOLUME. FLOW (M3 X 1010) 

Fig. 25. Entrainment impact of increased water withdrawal 

on maximum sustainable yield (MSY) of alewife in Lake 

Michigan (1975). Arrow indicates total design flow for all 

water intakes in 1975. 

73 

----------_._--------- . 
29r----.----.-----r----.-----,----r----,----,-----r---~ 

27 

26 

'2; 

- 25 x 

l!l 

~ 2l! 

1fJ 

1fJ 

~ 23 o 

22 

21 

20 

No water wIthdrawal 

-----------

(f ) 0.4331 x 10- 12 

max -12 + (p ) 0.17l2 x 10 max -14 + (hmax ) 0.1743 x 10 

(favg) 0.1071 x 10- 12 

( ) 0.1756 x 10- 13 + Pavg 

(h ) 0.2236 x 10- l5 

+ avg 

1~~--~-----2~--~----~4--~~----~6----~----8~--~--~10 

VOLUME FLOW (M3 X 10lD) 

Fig. 26. Combined entrainment and impingement impact of 

increased water withdrawal on biomass of alewife in Lake 

Michigan (1975). Arrow indicates total design flow for all 

water intakes in 1975. 

31.----,-----r----,----,-----r----,----,-----r----,----, 

29 

27 

~ 25 

x 

l!l 

~ 

)_ 23 1fJ 

~ 

21 

19 

No water wIthdrawal ----------------------------------------------------

) 0.1071 x 10- 12 (favg 

) 0.1756 x 10- 13 + (Pavg 

h ) 0.2236 x 10- 15 + ( avg 

( f ) 0.4331 x 10- 12 

max 

0.1712 x 10- 12 + (Pmaxl 

+ (hmax ) 0.1743 x 10- l4 

1~L---~----~2-----L----~l!--~~--~6~--~----~8~--~----7,10 

VOLUME FLOW (M3 X 10lD) 

Fig. 27. Combined entrainment and impingement impact of 

increased water withdrawal on maximum sustainable yield (MSY) 

of alewife in Lake Michigan (1975). Arrow indicates total 

flow for all water intakes in 1975. 

74 
- B = 279,266,660 - 0.00002371Q, p = 0.1756 X 10- 13 , h = 0.2236 X 10- 15 • 

The impact of entrainment on biomass of the standing stock is less than the 

impact of impingement. Biomass decreases slowly due to entrainment of larvae 

and eggs as volume flow increases (Fig. 24). The reduction in the standing 

stock resulting from entrainment of larvae and eggs is 0.00407 (0.41%) at a 

volume flow of 4.8 x 1010 m3/yr. 

The impact of entrainment on the yield to the fishery is also less than 

the impact of impingement. The relation between the maximum sustainable yield 

and volume flow, considering only entrainment of eggs and larvae, is given by 

the equations: 

MSY = 30,000,000 - 0.00003459Q, p_= 0.1712 x 10- 12 , h_= 0.1743 X 10- 14 

MSY = 30,000,000 - 0.000003557Q, p = 0.1756 X 10- 13 , h = 0.2236 X 10- 15 • 

The maximum sustainable yield decreases slowly as the volume withdrawn 

increases (Fig. 25), and at a volume of 4.8 x 10 10 m3/yr the proportion reduction in the maximum sustainable yield is 0.0056 (0.56%). 

Under equilibrium conditions the surplus production model predicts that 

the impact of entrainment and impingement is additive. The combined impact of 

entrainment and impingement on the standing stock and the maximum sustainable 

yield is given by the following equations: 

B = 279,266,660 - 0.0008081Q, f = 0.4331 X 10- 12 , p = 0.1712 X 10- 12 , 

h = 0.1743 X 10- 14 • 

B = 279,266,660 - 0.0001665Q, f = 0.1071 X 10- 12 , p = 0.1756 X 10- 13 , 

h = 0.2236 X 10- 15 • 

MSY = 30,000,000 - 0.0001212Q, f = 0.4331 X 10- 12 , p = 0.1712 X 10- 12 , 

h = 0.1743 X 10- 14 • 

- - MSY = 30,000,000 - 0.00002498Q, f = 0.1071 X 10- 12 , P = 0.1756 X 10- 13 , 

h = 0.2236 X 10- 15 • 

At a flow of 4.8 x 1010 m3/yr the proportion reduction in the standing stock 

resulting from entrainment and impingement is 0.0286 (2.86%). The proportion 

reduction in the maximum sustainable yield resulting from entrainment and 

impingement is 0.398 (3.98%). 

With observed volume flows the entrainment and impingement coefficients 

must be increased substantially for impingement and entrainment to have a 

large impact on standing stock and yield. Alternatively, with the observed 

entrainment and impingement coefficients, a substantial increase in volume 

flow is necessary to produce a large impact. 

Ye 11 ow Perch 

The impacts of entrainment and impingement on yellow perch are not as 

large as the impacts on alewife. 

The impingement coefficient for the Pulliam plant (Green Bay) is much 

75 
------- --~--~--

higher than those for intakes on the main body of Lake Michigan, so the 

average impingement coefficient was calculated using the coefficients for the 

15 other sampled intakes. 

The average impingement coefficient for yellow perch in Lake Michigan is 

0.6705 x 10- 14 and the highest impingement coefficient is 0.2962 x 10- 13 • The 

relations between biomass, maximum sustainable yield, and volume flow, 

considering only impingement are: 

B = 12,265,439 - 0.0000004974Q, f = 0.6705 X 10- 14 

B = 12,265,439 - 0.000002197Q, f = 0.2962 X 10- 13 

MSY = 741,869 - 0.0000004974Q, f = 0.6705 X 10- 14 

MSY = 741,869 - 0.000002197Q, f = 0.2962 X 10- 13 

The maximum egg and larval entrainment coefficients for yellow perch (excluding Pulliam) are 0.1759 x 10- 13 and 0.1431 x 10- 15 , respectively. The 

average egg and larval entrainment coefficients are 0.2942 x 10- 14 and 0.3883 

x 10- 16 , respectively. The relation between biomass of the standing stock and 

volume flow, considering only entrainment, are: 

B = 12,265,439 - 0.000001315Q, p_= 0.1759 x 10- 13 , h_= 0.1431 X 10- 15 

B = 12,265,439 - 0.0000002211Q, p = 0.2942 X 10- 14 , h = 0.3883 X 10- 16 • 

The relation between maximum sustainable yield and volume flow, considering 

only entrainment, are: 

- - MSY = 741,869 - 0.00000002211Q, p = 0.2942 X 10- 14 , h = 0.3883 X 10- 16 

MSY = 741,869 - 0.0000001315Q, p = 0.1759 X 10- 13 , h = 0.1431 X 10- 15 • 

The combined impact of entrainment and impingement on the standing stock 

and maximum sustainable yield of yellow perch are given by the equations 

below: 

- - B 12,265,439 - 0.0000007185Q, f = 0.6705 X 10- 14 , P = 0.2942 X 10- 14 , 

h = 0.3883 X 10- 16 

B = 12,265,439 - 0.000003513Q, f = 0.2962 X 10- 13 , P = 0.1759 X 10- 13 , 

h = 0.1431 X 10- 15 

MSY = 741,869 - 0.00000007185Q, f = 0.6705 X 10- 14 , P = 0.2942 X 10- 14 , 

h = 0.3883 X 10- 16 

MSY = 741,869 - 0.0000003513Q, f = 0.2962 X 10- 13 , P = 0.1759 x 10- 13 , 

h = 0.1431 X 10- 15 • 

As the volume flow increases, biomass of the standing stock (Fig. 28) and the 

maximum sustainable yield (Fig. 29) decrease slowly. Assuming the capacity 

withdrawal of 4.8 x 1010 m3 and the average entrainment and impingement 

coefficients, the proportion reduction in standing stock of yellow perch is 

0.0028 (0.28%) and the proportion reduction in maximum sustainable yield is 

0.0047 (0.47%). 

76 
W 

::: 

x 

co 

~ 

(f) 

(f) 

IT 

L: 

0 

OJ 

13~--~----,----,-----r----r----r----,----,-----r--~ 

12 

11 

10 

(f )0.6705 x 10-14 avg -14 (p )0.2942 x 10 avg 16 (h )0.3883 x 10 avg 

-12 (fs)0.6427 x 10 

-13 (ps)0.1789 x 10 

-14 ChS) 0.3598 x 10 

No water wlthdrdwal 

(f )0.2962 x 10-13 max -13 (p )0.1759 x 10 max -15 (hmax )0.1431 x 10 . 

~L---~-----2L---~----~---rL---~----~----~--~----~10 

VOLUME FLOW (M3 X 10lD) 

Fig. 28. Combined impingement and entrainment impact of increased water withdrawal on biomass of yellow perch in Lake Michigan. Average and maximum co- [5J 

efficients have been calculated from all sampled power plants except Pulliam. 

Arrow indicates total design flow for all water intakes in 1975. 

en 

o 

>-

(f) 

::E 

8.----,----,-----,----,-----,----,----,-----,----,----, 

7 

5 

(f )0.6705 x 10- 14 

avg -14 (p )0.2942 x 10 avg 16 (h )0.3883 x 10- avg 

-1 (£5)0.6427 x 10 -13 (Ps)O .1789 x 10 -l4 (hs)0.3598 x 10 

No water wlthdrawal 

(f )0.2962 x 10- 13 

max -13 

(Pmax)0.17s9 x 10 

(h )0.1431 x 10-15 max 

4~--~----~----~--~--~~----~--~----~----~--~ 

o 2 8 10 

VOLUME FLOW (M3 X 10lD) 

Fig. 29. Combined impingement and entrainment impact of increased water withdrawal on maximum sustainable yield (MSY) of yellow perch in Lake Michigan. 

Average and maximum coefficients have been calculated from all sampled power 

plants except Pulliam.[5J Arrow indicates total design flow for all water intakes in 1975. 

77 
Smelt 

The impact of impingement and entrainment on smelt is similar to the 

impact on alewife. The average impingement coefficient is 0.3717 x 10- 13 and· 

the highest impingement coefficient is 0.3149 x 10- 12 • The relation between 

biomass of the standing stock and volume flow for these impingement coefficients are: 

- B = 15,604,000 - 0.000001487Q, f = 0.3717 X 10- 13 

B = 15,604,000 - 0.00001259Q, f = 0.3149 X 10- 12 • 

Bi omass of the standi ng stock decreases slowly as the vol ume flow withdrawn 

increases. At a flow of 4.8 x 10 10 m3 jyr, the 1akewide impingement L~I) of 

smelt 'was estimated to be 1.86 x 104 kg (Table 6). Based on the 1975 biomass 

estimate of 25,280,000 kg, the proportion of the standing stock impinged (~IjB1975) is 0.0007 (0.07%). The proportion reduction in the standing stock 

(Fig. 30) is 0.0046 (0.46%). 

The impact of impingement on yield to the fishery also is small. The 

relation between the maximum sustainable yield and volume flow is given by the 

equations: 

MSY = 2,500,000 - 0.0000003717Q. f = 0.3717 X 10- 13 

MSY = 2,500,000 - 0.000003149Q, f = 0.3149 X 10- 12 • 

The maximum sustainable yield decreases slowly as the volume flow increases 

(Fig. 31). The proportion reduction in yield due to impingement is 0.0071 

(0.71%) at 4.8 x 10 10 m3 jyr. 

The maximum egg and larval entrainment coefficients are 0.1519 x 10- 12 

and 0.9242 x 10- 14 • The average egg and larval entrainment coefficients are 

0.2208 x 10- 13 and 0.2099 x 10- 14 • The relation between biomass of the standing stock and volume flow, considering only entrainment, are: 

B = 15,604,000 - 0.0000009672Q, P = 0.2208 X 10- 13 , h = 0.2099 X 10- 14 

B = 15,604,000 - 0.000006734Q,p = 0.1591 x 10- 12 , h = 0.9242 X 10- 14 • 

The impact of entrainment on standing stock biomass of smelt is less than the 

impact of impingement. As volume flow increases, biomass decreased slowly due 

to entrainment of eggs and larvae (Fig. 32). The reduction in the standing stock due to entrainment of larvae and eggs is 0.00298 (0.3%) in 1975. 

The impact or entrainment on yield is less than the impact of impingement 

on yield. The relation between the maximum sustainable yield and volume flow, 

considering only the impact of entrainment, is given by the following 

equations: 

MSY = 2,500,000 - 0.000001683Q, p_= 0.1591 x 10- 12 , h_= 0.9242 X 10- 14 

MSY = 2,500,000 - 0.0000002418Q, p = 0.2208 X 10- 13 , h = 0.2099 X 10- 14 • 

The maximum sustainable yield decreases slowly as volume flow withdrawn 

increases (Fig. 33). The proportion reduction in yield due to entrainment is 

0.0046 (0.46%) in 1975. 

78 
! 

I 

I 

I 

I 

I 

I 

I 

I 

I 

! 

I 

I 

I 

15r----,----r-,---,----r-,---,----,r---,_---,----,_----

No water withdrawal 

~ 

-----------~-------------- -------------

-- (f) 0.3717 x 10- 13 - ________ ~ av g 

S ~15r ~ (f ) 0.3l49 

~ 

x 10- 1 

max x 

-~ 

-

Ul 

Ul 

a: 

L 

o 

ro - 11!-

VOLUME FLOW (M3 X 1 OlD) 

Fig. 30. Impingement impact of increased water withdrawal 

on biomass of smelt in Lake Michigan (1975). Arrow indicates 

total design flow for all water intakes in 1975. 

25r----r----r----,----r---,_---,~--,_--_,----,---_, 

No water withdrawal 

25r'-::::-::-...::...;-:...:::.-:::..::--~--:..=.--=-:::- -~--~--::..=.-~--:-::---:-:-:-:---~---=1:-;----------------------------------1 

(f ) 0.3717 x 10- 13 

avg 

21! 

22 

21 

VOLUME FLOW (M3 X 1010) 

Fig. 31. Impingement impact of increased water withdrawal 

on maximum sustainable yield (MSY) of smelt in Lake Michigan 

(1975). Arrow indicates total design flow for all water intakes in 1975. 

79 

~~~ --- ----~ 
:0 

S 

x 

'-" 

~ 

(f) 

(f) 

cr: 

'" 0 

OJ 

16.----,----,1-----r----'1-----r----,-1---,-----1r----r----, 

15tjllfNo water withdrawal 

--- -13 ___________ 

(p lO.2208x10 ~vg -14 - __ + (h avg 1 0.2099 x 10 

(Pmaxl 0.1591 x 10- 12 

+ (hmaxl 0.9242 x 10- 14 -----------= 

~ I • I I 

2 4 6 8 10 

VOLUME FLOW (M3 X 1010) 

Fig. 32. Entrainment impact of increased water withdrawal 

on biomass of smelt in Lake Michigan (1975). Arrow indicates 

total design flow for all water intakes in 1975. 

26~--~----._----r_--~----.-----r---_,----_r~--,_--~ 

x 

'-" 23 ~ 

22 

21 

No water WIthdrawal 

( 1 0.1591 x 10- 12 

Pmax -14 

+ (hmaxl 0.9242 x 10 

2~-L---~----~2-----L----~4---;~----6L---~-----8~--~--~10 

VOLUME FLOW (M3 X 1010) 

Fig. 33. Entrainment impact of increased water withdrawal 

on maximum sustainable yield (MSY) of smelt in Lake Michigan 

(1975). Arrow indicates total design flow for all water intakes in 1975. 

80 

.;, " ; 
The combined impact of entrainment and impingement on the standing stock 

and maximum sustainable yield are given by the equations below: 

B = 15,604,000 - 0.00001934Q, f = 0.3149 X 10- 12 , P = 0.1591 X 10- 12 , 

h = 0.9242 X 10- 14 

- B = 15,604,000 - 0.000002454Q, f = 0.3717 X 10- 13 , P = 0.2208 X 10- 13 , 

h = 0.2099 X 10- 14 

MSY = 2,500,000 - 0.000004832Q, f = 0.3149 X 10- 12 , P = 0.1591 X 10- 12 , 

h = 0.9242 X 10- 14 

- - MSY = 2,500,000 - 0.0000006135Q, f = 0.3717 X 10- 13 , P = 0.2208 X 10- 13 , 

h = 0.2099 X 10- 14 • 

At a flow of 4.8 x 10 10 m3 jyr the proportion reduction in the standing stock 

resulting from the combined impact of entrainment and impingement is 0.00755 

(0.76%)(Fig. 34). The proportion reduction in the maximum sustainable yield resulting from entrainment and impingement is 0.0118 (1.18%)(Fig. 35). 

DISCUSSION OF MODELING RESULTS 

Direct estimation of the biomass of a fish stock is difficult and assessment of the impact of entrainment and imp; ngement cannot be made wi thout a 

model that describes the response of the population to these impacts. Fishery 

models can be applied for estimation of stock biomass and also can be applied 

for environmental impact assessment after only slight modifications. Fishery 

models have been widely applied and the assumptions and difficulties 

associated with the applications of these models are well known. 

The impact of impingement can be assessed just as the impact of a fishery 

is assessed. The model for yield to a fishery is identical to the model for 

impingement. For alewife the pattern of impingement during the year is 

similar to the pattern of catch from the commercial fishery (Table 38). Both 

the fishery and the power plants catch alewife as they move toward shore. To 

model the impact of entrainment, more substantial modification of the fishery 

models is necessary, but the modifications are straightforward and in this 

study the most direct and simplest modifications have been applied. 

The major weakness in application of fishery models,. as well as other 

models, for assessment of environmental impacts is the shortage of data for 

stock identification and parameter estimation. For fisheries undergoing dramatic changes, such as those of the Great Lakes, meaningful parameter 

estimation is extremely diffi cul t. Estimati on of parameters for the surpl us 

production models is difficult because the parameters are not well defined and 

they do not remain constant over an extended period on the Great Lakes. Both 

the parameters of the surplus production model are few in number and all of 

them can be estimated directly from catch and effort data. 

Using the available data and varying parameter values resulted in similar 

fits of the model to the observed catch and effort data (Table 39). For 

example, increasing k from 0.30 to 0.35 and decreasing Boo from 400,000,000 to 

300,000,000 for alewife increases the residual sum of squares by only a small 

81 

---- .~----.--. ---
tf) 

tf) 

a: 

L 

o 

lGr----,----,-----,----,----,-----,----, ____ ,-____ ,-__ -, 

15 

No water withdrawal 

----------------------------------------------------

( f 1 0.3149 x 10- 12 

max 

( 1 0.1591 x 10- 12 + Pmax 

+ (hmaxl 0.9242 x 10- 14 

(f 1 0.3717 x 10- 13 

dVg 

+ (p 1 0.2208 x 10- 13 

avg -14 

+ (havgl 0.2099 x 10 

(l) 14 

1~~--~----~----~--~--~~----L---~----~8-----L--~10 

VOLUME FLOW (M3 X 1010 ) 

Fig. 34. Combined entrainment and impingement impact of increased water withdrawal on biomass of smelt in Lake Michigan 

(1975). Arrow indicates total design flow for all water 

intakes in 1975. 

25r----,----,-----,----,----,-----,----,----,-----,----, 

No water wlthdrawal 

~ ---------------------------------------------------

24 

x 

~ 23 ~ 

rtf) 

::0:: 

22 

21 

( f 1 0.3149 x 10- 12 

max 

( 1 0.1591 x 10- 12 + Pmax 

(h 1 0.9242 x 10- 14 + max 

2%L---~----~2L----L----~4--~r-----~--~----~8~--~--~10 

VOLUME FLOW (M3 X 1010) 

Fig. 35. Combined entrainment and impingement impact of increased water withdrawal on maximum sustainable yield (MSY) 

of smelt in Lake Michigan (1975). Arrow indicates total 

design flow for all water intakes in 1975. 

82 
amount. Although the fit of the model to the observed data is good, the 

individual parameter estimates might not be of similar accuracy. 

Table 38. Comparison of commercial alewife catch from district 

WMI in Green Bay and observed impingement at Pulliam Power 

Plant during 1975. 

Month Commercial Catch (kg) Observed Impingement (kg) 

January 0 0 

February 9 0 

March 13 0 

April 78 0 

May 79,655 267 

June 2,813,451 13,375 

July 2,152,849 7,195 

August 978,809 3,383 

September 564,083 166 

October 66,441 86 

November 2 79 

December 0 6 

Table 39. Residual sum of squares for fit of surplus production model to 

alewife catch and effort data. 

Q 0.000005 0.000010 0.000020 

Sum of squares for K = 0.25 

Bmax 

0.30000000[+09 0.71559846[+15 0.49805058[+15 0.13285475[+16 

0.40000000[+09 0.43346152[+15 0.32332165E+15 0.12343199[+16 

0.50000000[+09 0.27269751[+15 0.24085464[+15 0.11733996[+16 

Sum of squares for K = 0.30 

Bmax 

0.30000000[+09 0.58970330[+15 0.25229185[+15 0.70890663[+15 0.40000000[+09 0.32373584[+15 0.18022458[+15 0.58793512[+15 

0.50000000[+09 0.22241908[+15 0.26774588E+15 0.52183262[+15 

Sum of squares for K = 0.35 

Bmax 

0.30000000[+09 0.52456825[+15 0.19093856[+15 0.31439214[+15 

0.40000000[+09 0.30174615[+15 0.34051601[+15 0.31592491E+15 

0.50000000[+09 0.28995566E+15 0.76056059E+15 0.41336671E+15 

83 
To apply the surpl us producti on model for assessment of the impact of 

entrai nment, the production of eggs and survival of eggs and 1 arvae must be 

estimated. Survival of eggs and 1 arvae was determi ned from estimates of the 

number of eggs produced and the assumption that the population was in 

equilibrium. The sensitivity of the estimates of impact to changes in 

survival of eggs and larvae should be investigated. 

The parameter estimates for the dynamic pool model are based on entirely 

different kinds of data than those of the surplus production model. The 

growth parameters and total mortal i ty coeffi ci ents were estimated from age 

structure and growth data available in the literature. Age at maturity and 

age at recruitment into the fishery also were obtained from the literature. 

The fishing mortality coefficient, F, was estimated from the surplus 

production model parameters as F = qE. This is the only connection between 

the two model s. The 1 arval and egg mortal ity parameters were adjusted under 

the assumption that the stocks were in equilibrium. 

In a study such as this where a mathematical model is applied to assess 

an impact, there is no direct method to determine whether or not the result is 

reasonable. Therefore, the applications of the dynamic pool and surplus 

production models were kept as independent as possible so a comparison of the 

results obtained by the two models could be used as a basis for evaluating the 

reliability of the estimates of impact. First, the surplus production model 

was applied. Then, the dynamic pool model was applied using the value of F 

estimated from the surpl us producti on model. All other parameter estimates 

are independent. The close agreement between the results obtained with the 

two models gives some degree of confidence in the results. 

Al though the resul ts of the two model s agree, there mi ght be substanti al 

errors in the estimation of the population parameters in both the surplus 

production and the dynamic pool models. These errors could produce an error 

in estimation of biomass which would affect the estimate of impact. However, 

even a substantial error in the estimate of biomass did not result in a 

meaningful change in the level of impact on Green Bay. The relation between 

the estimate of the proportion impinged and the biomass of yellow perch in 

Green Bay is shown in Fig. 36. A large increase in the estimate of population 

bi amass decreases the 1 evel of impact only sl i ghtly. The decrease in the 

estimate of biomass produces a larger change than an increase but decreasing 

the bi amass estimate by one-half only increases the proporti on impi nged from 

less than 0.001 to 0.0015. Because the level of impact is small, large errors 

of estimation do not change the level of impact substantially. 

The U.S. Fish" and Wildlife Service estimated the adult alewife population 

vulnerable to bottom trawling to be from 86,000,000 to 131,600,000 kg in 1975 

[24]. Using the fishery data and the population models we estimated the 

alewife biomass in 1975 to be 206,400,000 kg. Although our estimate is nearly 

twice as large as the estimate made by the Fish and Wildlife Service, it is 

probably an underestimate of the total alewife biomass in Lake Michigan. The 

commercial fishery for alewife is not lakewide and unless there is complete 

mixing of the alewife population, the estimates obtained with the surplus 

production model should be low. 

The 1975 rainbow smelt biomass in Lake Michigan was estimated to be 

13,700,000 kg by the U.S. Fish and Wildlife Service [27J. The biomass of 

84 
2.0 

o 1.5 w 

Cl 

z 

(L 

L 

~ 

2 1.0 fa: 

o 

(L 

o 

cc: 

(L 

0.5 

t 

14 

BIOMASS (KG X 106) 

Fig. 36. Relation between estimate of population biomass 

and estimate or proportion of biomass standing stock impinged 

for yellow perch in Green Bay (1975). Arrow indicates estimated biomass in 1975. 

'2; 

x 

'-" ;S 

0 

---' 

w 

~ 

>-

OBSERVED 

- - - - - - PREDICTED 

6 

L! 

2 / ,., 

1~·~GO~~~~~1~9~G5~~--~~1-9L70~~--~~1-97L5~~--~~1~980 

YEAR 

Fig. 37. Observed and predicted yields for yellow perch in 

Green Bay (1960-1977). 

85 
smelt in 1975 was estimated to be 25,280,000 kg in this study. There do not 

appear to be lakewide estimates of the biomass of yellow perch that can be 

compared with out estimate of 15,000,000 kg in 1975. 

The lakewide application of the surplus production model assumes complete 

mixing of stocks within the lake. This assumption is not valid and to determine what influence this might have on the results, the impact of the Pulliam 

Power Plant on yellow perch in Green Bay was investigated. Catch and effort 

data for yellow perch in Green Bay are listed in Table 40. The effort data 

are in terms of lifts of shallow trap nets. The parameter estimates for the 

surplus production model are: 

q = 0.0000015 

k = 0.20 

Boo = 7,000,000 kg 

The carrying capacity of Green Bay appears to be about 50% of the lakewide 

carrying capacity. The growth rates and catchability coefficients for yellow 

perch are about the same in Green Bay and Lake Michigan. 

The fit of the model to the observed yield data in Green Bay (Fig. 37) is 

similar to the lakewide fit (Fig. 20). In Green Bay, as in the rest of Lake 

Michigan, a large decrease in catch occurred between 1963 and 1965. The model 

does not accurately predict catches prior to 1965 but predicts catches well 

from 1965 to 1977. It would appear that the decrease in catch is not related 

to overfishing. The stock production curve for Green Bay indicates that the 

yellow perch population is not over-exploited by the commercial fishery. The 

MSY of 350,000 kg occurs at a biomass of about 3,500,000 kg. 

T~ble 40. Total catch, trap net effort 

(number of lifts), and catch per unit of Tabl e 41. Power plant-related parameters for effort for yellow perch in Green Bay, 1960-1977. impact of Pulliam Power Plant on yellow perch population of Green Gay (surplus production model). 

Year Catch (kg) Effort CPUE 

Parameter Estimate 

1960 695387.63 29096.64 23.90 

1961 1031650.56 43686.96 23.61 Volume flow (m3 /yr) 0.774 x 109 1962 989950.88 28273.39 35.01 

1963 1039157.50 27513.02 37.77 Biomass impinged (kg) 0.4979 x 104 

1964 602275.00 33451.54 18.00 Proportion impinged 0.9957 x 10- 3 

1965 243885.56 32024.59 7.62 Impingement coefficient 0.6427 x 10- 12 

1966 161835.25 18713.91 8.65 Number of eggs entrained 0.4526 x 107 

1967 333137.19 18483.43 18.02 Proportion of eggs entrained 0.2772 x 10- 4 

1968 121793.81 11811. 77 10.31 Egg entrainment coefficient 0.1789 x 10- 13 

1969 149966.06 11871.31 12.63 Number of larvae entrained 0.9102 x 10 6 

1970 167150.69 13769.38 12.14 Proportion of larvae entrained 0.5574 x 10- 3 

1971 112734.44 13087.94 8.61 Larvae entrainment coefficient 0.3598 x 10- 14 

1972 105107.39 12353.30 8.51 

1973 107444.19 12583.75 8.54 

1974 358055.94 18059.01 19.83 

1975 221815.31 28387.89 7.81 

1976 163233.44 23854.13 6.84 

1977 265166.50 26083.35 10.17 

86 
Applying the surplus production model, the biomass of yellow perch in 

Green Bay in 1975 was estimated as 5,206,666 kg. Applying this estimate of 

biomass together with the observed volume flow and numbers and biomass 

impinged and entrained at the Pulliam Power Plant gave the parameter estimates 

listed in Table 41. The impingement and entrainment coefficients are higher 

when the impact on Green Bay is assessed than when the impact on Lake Michigan 

is assessed. This is expected because the biomass available to the Pulliam 

plant is considerably reduced when only Green Bay is under consideration. 

The estimate of the proportion of yellow perch in Lake Michigan impinged 

at Pulli.am Power Plant is 0.4978 x 10- 3 • The proportion of the biomass in 

Green Bay estimated to be impinged is 0.9957 x 10- 3 • The. yellow perch 

population of Green Bay in 1975 was about 50% of the lakewide estimate for 

1975. From the proportion of biomass in the lake impinged and the percent of 

the population of the lake estimated to be in Green Bay the proportion 

impinged in Green Bay is estimated as 0.4979 x 10- 3 which is identical to the 

estimated obtained using only Green Bay data. 

Because the yellow perch entrainment and impingement coefficients are 

hi gh when Green Bay is consi dered separately. the impacts of entrai nment and 

impingement increase substantially as volume flow is increased. The relation 

between yellow perch standing stock biomass, maximum sustainable yield, and 

volume flow are given by the equations: 

B = 5,824,315 - 0.000046480 

MSY = 350,000 - 0.0000046480, f5 = 0.1285 x 10- 11 , P5 = 0.3578 x 10-13 , 

h5 = 0.7195 x 10- 14 • 

As volume flow increases the standing stock biomass and maximum sustainable 

yield slowly decrease (Figs. 38 and 39). At a flow of 7.74 x 108 m3 /yr, the 

reduction in standing stock of yellow perch in Green Bay is 0.0061 (0.61%) and 

the reduction in MSY is 0.0103 (1.03%). Consideration of Green Bay separately 

from the rest of Lake Michigan does not result in a significant change in the 

estimate of the impact of water withdrawal. 

The results of this study indicate that the cumulative impacts of 

impingement and entrainment resulted in relatively small decreases in standing 

stocks and yields of alewife, smelt, and yellow perch in Lake Michigan. The 

major source of uncertainty in the results reported here comes from the lack 

of data for parameter estimation, but even large errors in estimation woul d 

not cause a great change in the estimated level of impacts during 1975. 

Al though the present level (capacity) of water withdrawal does not reduce 

standing stocks or yields of these species by more than a few percent, the 

intake-related losses should be evaluated in light of the recent status of 

each population in Lake Michigan. 

The published estimates of standing stock biomass of alewife available to 

trawls (1967-1978) [24J indicate cyclic fluctuations between 40 and 120 

million kilograms, and our estimates, based on the fishery indicate a peak 

biomass of ~206 x 106 kg in 1975. Recent estimates of the annual consumption 

of alewife by salmonid predators in Lake Michigan [34J indicate a maximum of 

30% of the standing stock biomass was consumed in 1975, a peak year in the 

cycle of alewife biomass fluctuations, and a maximum of 100% in 1977, a year 

87 
'" o 

x 

G.0r----r----~---,----~---,----_r----~--_r----:_--_, 

No water withdrawal 

5.8 -----------------------------------------------------

~ 5.6 

u "" a 

~ 

(f) 

I.L 

a 5.lJ (f) 

(£5) 0.64"7 x 10- 12 

+ (ps) 0.1789 x 10- 13 

+ (\) 0.3598 x 10- 14 (f) 

a: 

::;: 

a 

~ 

(!) 

5.2 

5.0~--~----7_--~----~--~----_L----L----L----L---~ o lj 6 8 10 

VOLUME FLOW 1M3 X 109) 

Fig. 38. Combined entrainment and impingement impact of increased water withdrawal on biomass of yellow perch in Green 

Bay. Arrow indicates total design flow for all water intakes 

on Green Bay in 1975. 

on 

o 

>-

(f) 

::E 

lJr----r----.---_,----.----.-----r----.----r----.---~ 

No water withdrawal 

(£5) 0.6427 x 10- 12 

+ (ps) 0.1789 x 10- 13 

+ (h s

) 0.3598 x 10- 14 

~·~--~--~~2----~--~lJ----~--~6~--~----8~--~--~IO 

VOLUME FLOW 1M3 X 109) 

Fig. 39. Combined entrainment and impingement impact of increased water withdrawal of maximum sustainable yield (MSY) 

of yellow perch in Green Bay. Arrow indicates total design 

flow for all water intakes on Green Bay 1975. 

88 
when estimated al ewife bi omass was extremely low. Under natural conditions, 

the numbers of predatory fishes are a direct function of reproductive success, 

natural mortality rates, and food supply. However, the numbers of salmonids 

in Lake Michigan are primarily under human control. Social pressures to 

increase salmonid stocking in Lake Michigan have resulted in the stocking of ...... 12 million salmonids annually since 1973 and projected stocking rates of 15 

million per year by 1985. The potential effects of overstocking salmonids and 

overcropping alewife are becoming serious issues. The focus of fish management and research efforts must be directed toward forage fish management via 

allocation of forage production among trophic, commercial, and other 

interests. For example, the loss of alewife biomass due to commercial fishing 

in 1975 was approximately 16 x 106 kg. Assuming a limitation on available 

forage, this biomass would have produced ...... 2 x 106 kg of salmonids (assuming a 

forage to predator conversion ratio of 7:1). Similarly, the loss of alewife 

to water intakes ( ...... 2 x 106 kg in 1975) would convert to ...... 280 thousand kilograms of salmonids. 

Estimates of the minimum standing stock biomass of rainbow smelt in Lake 

Michigan indicate fluctuations between 11 and 16 million kg between 1973 and 

1978 [27J and ...... 25 x 106 kg in 1975 (this report). Although salmonid predation 

on smelt is not well quantified, it was recently estimated as ...... 5.0 x 106 kg or 

20% of the 1975 standing stock biomass [34J. Commercial fishing in 1975 

harvested 0.5 x 106 kg (2%) and sport fi shi ng accounted for ...... 1.3 x 106 kg 

(5.2%). The reductions in standing stock of rainbow smelt due to water 

intakes was estimated to be 0.75%. The status of the rainbow smelt population 

seems to be partially related to the status of the alewife population and the 

level of predation by salmonids. Although the smelt population has played a 

secondary role in the trophic system of Lake Michigan in the past, it may 

become a more valuable forage base if the alewife population is depleted to 

the pOint of being unable to support the predatory pressure. 

Yellow perch are not a forage species for salmonids. The yellow perch 

popul ati on in Lake Mi chi gan has fl uctuated greatly si nce 1960. Apparently. 

the standing stock of yellow perch was ...... 10.7 x 106 kg lakewide and 5.2 x 106 

kg in Green Bay in 1975. Nei ther popul ati on seems to be impacted by the 

combined mortalities due to fishing and water intakes. 

89 
1. 

REFERENCES 

CDM/Limneti cs. 1977 . The 1 ake-wi de effects of 

entrainment on the Lake Michigan fish populations. 

NIPSCO, IMPCO, and CPCO. 

impingement and 

Report to CECO, 

2. Saila, S. B. and E. Lorda. 1977. Sensitivity analysis appl ied to a 

matrix model of the Hudson River striped bass population. In: W. Van 

Winkle (ed.), Conference on Assessing the Effects of Power Plant-Induced 

Mortality on Fish Populations. Pergamon Press, Inc. p. 311-331. 

3. Horst, T. J. 1975. The assessment of impact due to entrainment of 

ichthyoplankton. In: S. B. Sail a (ed.), Fisheries and Energy 

Production: A Symposium. Lexington Books, Lexington, Massachusetts. p. 

107 -118. 

4. Horst, T. J. 1977. Effects of power station mortality on fish 

population stability in relationship to life history strategy. In: W. 

Van Wi nkl e (ed.), Conference on Assessi ng the Effects of Power Pl antInduced Mortality on Fish Populations. Pergamon Press, Inc. p. 297-310. 

5. Eraslan, A. H. et al. 1975. A computer simulation model for the striped 

bass young-of-the-year population in the Hudson River. ORNL Publ. No. 

766. 208 pp. 

6. Van Winkle, W. et al. 1974. A striped-bass population model and 

computer programs-.-ORNL Report No. 643. 195 pp. 

7. Van Winkle, W. (ed.). 1977. Conference on Assessing the Effects of 

Power Plant-Induced Mortality on Fish Populations. Pergamon Press, 

Inc. 361 pp. 

8. Swartzman, G. L., R. B. Deriso, and C. Cowan. 1978. Comparison of 

simulation models used in assessing the effects of power plant-induced 

mortality on fish populations. Nuclear Regulatory Commission. 155 pp. 

9. Ricker, W. E. 1975. Computation. and interpretation of biological 

statistics of fish populations. Fish. Res. Board Can. Bull. No. 191. 

382 pp. 

10. Goodyear, C. P. 1977. Mathematical methods to evaluate entrainment of 

aquatic organisms by power plants. U.S. Fish and Wildlife Service. 

Topical Briefs on Electric Power Generation No.3. 17 pp. 

11. Goodyear, C. P. 

adult approach. 

1978. Entrainment impact estimates using the equivalent 

U.S. Fish and Wildlife Service Report. 14 pp. 

12. Barnthouse, L. W., D. L. DeAngelis, and S. W. Christensen. 

empirical model of impingement impact. ORNL Publ. No. 1289. 

1979. 

20 pp. 

An 

13. Van Winkle, W., S. W. Christensen, and J. S. Suffern. 1979. 

Incorporation of sublethal effects and indirect mortality in modeling 

population-level impacts of a stress, with an example involving powerplant entrainment and striped bass. ORNL Publ. No. 1295. 24 pp. 

90 
14. Sharma, R. K. and R. F. Freeman, III. 1977. Survey of fish impingement 

at power plants in the United States: Vol. I. The Great Lakes. Argonne 

National Laboratory/Environmental Impact Studies Division Report, ANL/ES56. 

15. SAS Institute Inc. 1979. SAS User's Guide - 1979 Edition. SAS 

Institute Inc., Raleigh, North Carolina. 

16. Lucas, H. F., Jr. 1979. Radiological and Environmental Research 

Division, Argonne National Laboratory, personal communcation. 

17. Toohey, R. E., J. Rundo, and T. J. Kotek. 1978. A user's guide to 

PLOTIN/MYPLOT: A general -purpose plotting routine for use with AMD 

graphics. ANL/RER-78-3. 

18. Murarka, 1. P., S. A. Spigarelli, and D. J. Bodeau. 1978. Statistical 

comparison and choices of sampling designs for estimating fish 

impingement at cooling water intakes. In: L. D. Jensen (ed.), Proc. 4th 

National Workshop on Entrainment and Impingement. p. 267-280. 

19. Jude, D. J. 1979. Great Lakes Research Division, University of 

Michigan, Ann Arbor, Michigan, personal communication. 

20. Lake Michigan Cooling Water Intake Technical Committee. 1973. Lake 

Michigan intakes: Report on the best available technology. 

21. Otto, R. G., M. A. Kitchel, and J. O. Rice. 1976. Lethal and preferred 

temperatures of alewife (Alosa pseudoharengus) in Lake Michigan. Trans. 

Amer. Fish. Soc. 105, 96-1~ 

22. Werth, R. J., A. R. Resetar, and R. C. Evers. 1977. Report to Inland 

Steel Company, East Chicago, Indiana/Fish Monitoring Study: June 1976-

June 1977. 

23. Energy Impact Association. 1978. U.S. Steel Corporation, Gary 

Works/Fish Impingement-Entrainment Study. Summary Data Report. 

24. Hatch, R. W. 1979. Estimation of alewife biomass in Lake Michigan, 

1967-1978. U.S. Fish and Wildlife Service, Great Lakes Fishel'y 

Laboratory, Ann Arbor, Michigan, Administrative Report. 31 pp. 

25. Brandt, S. B. 1978. Thermal ecology and abundance of alewife (Alosa 

pseudoharengus) in Lake Michigan. Ph.D. Thesis, University of WisconsinMadison. 226 pp. 

26. Edsall, T. A., E. H. Brown, Jr., T. G. Yocum, and R. S. C. Wolcott, Jr. 

1974. Utilization of alewives by coho salmon in Lake Michigan. U.S. 

Fish and Wildlife Service, Great Lakes Fishery Laboratory, Jlnn Arbor, 

Michigan. 15 pp. 

27. Hatch, R. W. 1979. U.S. Fish and Wildlife Service, Great Lakes Fishery 

Laboratory, Ann Arbor, Michigan, personal communication. 

91 
28. Beverton, R. J. H. and S. J. Holt. 1957. On the dynamics of exploited 

fish populations. United Kingdom, Min. Agric. Fish., Fish. Invest. (Ser. 

2) 19. 533 pp. 

29. Gulland, J. A. (ed.). 1977. Fish population dynamics. John Wiley, New 

York. 372 pp. 

30. Brown, E. H., Jr. 1972. Population biology of alewives, Alosa 

pseudoharengus, in Lake Michigan, 1949-1970. J. Fish. Res. Board Can. 

29,477-500. 

31. Norden, C. R. 1967. Age, growth and fecundity of the alewife (Alosa 

pseudoharengus) in Lake Michigan. Trans. Amer. Fish. Soc. 96, 387-393. 

32. Brazo, D. C., P. J. Tack, and C. R. Liston. 1975. Age, growth, and 

fecundity of yellow perch, Perca flavescens, in Lake Michigan near 

Ludington, Michigan. Trans. Amer. Fish. Soc. 104, 726-730. 

33. Bailey, M. M. 1964. Age, growth, maturity, and sex composition of the 

American smelt (Osmerus mordax) of western Lake Superior. Trans. Amer. 

Fish. Soc. 93, 382-395. 

34. Stewart, D. J. and J. F. Kitchell. Managing forage fish with salmonid 

predators in Lake Michigan past, present and possibilities. 

Unpublished manuscript, Marine Studies Center, University of WisconsinMadison. 

92 

Q 
GLOSSARY OF TERMS 

Impi ngement: entrapment of fi shes by water intakes and thei r subsequent 

removal from the process stream by traveling screens. 

Entrai nment: entrapment of eggs and immature fi shes by water intakes and 

their passage through the traveling screens into the process stream. 

Ichthyopl ankton : IIfree-fl oati ngll or pl anktoni c fi sh 1 ife-stages. Eggs and 

larvae are included in this term. 

Traveling Screen: typically a 3/811 wire-mesh screen located upstream of the 

intake pumps as a final filter. 

a,b: parameters in the parabolic length-weight equation. 

B: biomass of the population at time t. 

Boo: environmental carrying capacity in terms of biomass (population size 

without fishing or water withdrawal). 

B(x): biomass of individuals of age x. 

Bo: population biomass at some initial time t. 

C: annual catch from the fishery in numbers or kg. 

CPUE: catch per unit effort in the fishery. 

0: density of fish in lake (kg). 

Di: density of fish at ith intake (kg). 

E: fishing effort in some standard units such as lifts of pound nets or trap 

nets. 

EUB: egg production per unit of female biomass. 

fi: annual impingement coefficient for water intake i. 

favg : average annual impingement coefficient for sampled water intakes. 

fmax : maximum annual impingement coefficient for sampled water intakes. 

F: instantaneous fishing mortality coefficient. 

G: number of eggs produced by the population during a period of one year, or 

the number at time t. 

Gl

i : number of eggs entrained at intake i at time t. 

~Gi: number of eggs entrained at water intake i during one year. 

G(o): the initial number of eggs produced by a cohort. 

93 

------~--.~~ 
havg : average annual larval entrainment coefficient for sampled intakes. 

hmax : maximum annual larval entrainment coefficient for sampled intakes. 

hi: larval entrainment coefficient for water intake i. 

I: number or biomass of fish impinged at time t. 

~Ii: number or biomass of fish impinged at water intake i during one year. 

k: population growth constant in surplus production model. 

K: growth parameter for weight of individual fish. 

!/.: length of an individual fish. 

J/.~: asymptotic length of an individual fish. 

J/.(x): length of an individual at age x. 

L: number of larvae at time t or at age x. 

L': number of larvae entrained at time t. 

~Li: number of larvae entrained at water .intake i during a period of one 

year. 

L(o): initial number of larvae produced by a cohort. 

M: instantaneous natural mortality coefficient. 

Mi : mortality resulting from impingement (assumed to = 1). 

M1: mortal ity rate of egg stage. 

M2 : mortal i ty rate of larvae. 

MSY: maximum sustainable yield. 

n: number of water intakes. 

N(x): number of individuals of age x. 

Pavg: average annual egg entrainment coefficient for sampled intakes. 

Pi: egg entrainment coefficient for water intake i. 

Pmax: maximum annual egg entrainment coefficient for sampled intakes. 

q: catchability coefficient for the commercial fishery. 

Qi: annual volume flow in m3 at water intake i. 

R: number of recruits entering exploited population. 

94 
i 

I 

i 

I 

I 

I 

! 

I 

I 

I 

I 

t: time in years. 

~tl: amount of time from spawning to absorption of yolk sac. 

~t2: amount of time from absorption of yolk sac to young-of-year stage. 

U;: integration constants for the dynamic pool model. oJ 

V: volume of 1 ake. 

Woo: asymptotic individual weight for the dynamic pool model. 

W(x): weight of an individual at age x. 

x: age. 

Xc: age when fish became catchable by commerci a 1 fi shery. 

xr: age when fish re recruited. 

xI: age when fish become impingeable. 

xm: age at maturi ty. 

xo: theoretical age when length is zero. 

Va: annual yield from the commercial fishery. , 

Y: yield from the commercial fishery at time t. 

Ye: equilibrium yield from fishery. 

~: mortality rate for prerecruit life-stages in surplus production model. 

95 
APPENDIX A 

DAILY IMPINGEMENT AND ENTRAINMENT DENSITIES 

Figs. A. l.a - A.16.i: Daily densities of each species/life stage at each 

sampled plant 

Figs. A.I.a-A.16.a: Impinged alewife. 

Figs. A.I. b-A.16. b : Impinged smelt. 

Figs. A.l.c-A.16.c: Impinged yellow perch. 

Figs. A.1.d-A.16.d: Entrained alewife eggs. 

Figs. A.I.e-A.16.e: Entrained alewife larvae. 

Figs. A.I.f-A.16.f: Entrained smelt eggs. 

Figs. A.I. g-A.16. g: Entrained smelt larvae. 

Figs. A.2.h-A.16.h: Entrained yellow perch eggs. 

Figs. A.2.i-A.16.i: Entrained yellow perch larvae. 

NOTE: Figures for plants not reporting a species group were excluded. 

Heavy solid lines on x-axis indicate values ( appropriate y-axis value. 

96 
'" ::E: 

o 

o 

o 

'-o 

w 

l.') 

z 

..... 

D-

~ 10-1 

a:: 

w 

OJ 

L 

::l 

z 10-2 

10-4

o , " , , Iii ~! lbh1I '+++' 

Figure R. 1. a ZION/RLEWIFE 

1+, t! !! 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

en 

L 

o 

o 

o 

'-o 

w 

l.') 

Z 

D-

~ 10-1 

a:: 

w 

CD 

L 

::l 

z 10-2 

10-3 

Figure A. 2.0 D.C.COOK/ALEWIFE 

'1'1 

365 

10 -4u o tlY q !II!!! ! ! ! "WI' I! l! I I I! I! I ! I ! ! ,! !! 1 t 1 ! ! ! t! I I ! ! ! !! ! ! I d, ,I, Ii ! ! Y" ! ! !! !!! I 

365 

JAN FEB MRR RPR MAY JUN JUL AUG SEP OCT NOV DEC 

97 
(Y) 

:::;: 

o 

o 

o 

.-< 

"- o 

w 

C) 

z 

...... 

Q.. 

~ 10- 1 

0: 

W 

co 

:::;: 

:::J 

z 10-2 

Figure R. 3.0 BRILLi/RLEWIFE 

10- ! ~ ,L.J 1 :I,! lJ ,lJ1 41 I II II, III "1 ill I 365 

o 

en 

:::;: 

o 

o 

o 

.-I 

"-o 

w 

C) 

z 

...... 

Q.. 

~ 10- 1 

0: 

W 

co 

:::;: 

:::J 

z 10-2 

JRN FEB MRR RPR MRi JUN JUL RUG SEP OCT NOV DEC 

Figure R. ~.o MICH CITi/RLEWIFE 

10-4 !.J til !W • I :! II I II ill 365 

o 

JRN FEB MRR RPR MRi JUN JUL RUG SEP OCT NOV DEC 

98 

=;;4#i'*-"'="'-"""""'~t-<"'~'-<&\~l'""""*"-"",,""""""".",iS','@4,,, "'_"'"" _'<"~ ,_,';,*,0, ",d,",,#.~Pj, ""'~ I""~ "mh~=""'''''."",""",:;;::: _ ;::; _ i_ , _, "~,Gl¥" ._~ .. ~= %"'""'*"""","~J>AAO&iii=" ,¥=,,_""<,," _, __ 
., 

:::E 

o 

o 

o 

...... 

" o 

w 

l:) 

:z: 

0.... 

~ 10-1 

a: 

w 

co 

:::E 

::J 

:z: 10-2 

Figure R. 5.0 PULLIRM/RLEWIFE 

10 .11 U I! dl 4,+,J ,4J -LH ! ! ! ! ! ! I ! !!! I, I I I I I I 365 

o 

., 

:::E 

o 

o 

o 

o " 

w 

l:) 

:z: 

0.... 

. ~ 10- 1 

a: 

w 

co 

:::E 

::J 

:z: 10-2 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R. 6.0 KEWRUNEE/RLEWIFE 

10-41 a 

---:::::!.'-"H:I~:'J.~::~J.::::'"~:::_'""::::-'"~~-''"-''"-''"-''"uc'-uc'-'",-,"-,,"~l. IWoM Ih+ I I !.I I: :/, !! !! !! .... ~' 365 

JAN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

99 
'i: 

o 

o 

o 

...... 

Cl 

W 

l:) 

Z 

...... 

0.... 

~ 10-1 

ex: 

~ ::;: 

~ 10-2 

Figure R. 7.0 POINT BERCH/RLEWIFE 

, 4.+.l J+l' lJ 10-1.\1 : !I: '" 365 

o 

'i: 

o 

o 

o 

-...... 

Cl 

W 

l:) 

Z 

...... 

0.... 

~ 10-1 

ex: 

w 

co 

::;: 

::J 

z 10-2 

JAN FEB MRR RPR MRI JUN JUL AUG SEP OCT NOV DEC 

Figure R. 8.0 PORT WRSH/RLEWIFE 

lO-Lh , , o ~::ij~' ~~::~~~~~~~~~~~~~~~~~~~~~~~ 'w.w'I' " I , ! !! !! I! I ! '._I~I~~I~I~I~~~LL~~~~~~ , !! ! , 111 

365 

JAN FEB MRR RPR MRI JUN JUL AUG SEP OCT NOV DEC 

100 

~,ii;;o".,...*,¥""",,~<"=.~k"." """~ ~_"""h ~-.- _'C7'_,-- 'r",""",~~ ~.,.-" '_""", "~""'''' ~,,""~""" =~'''~, ~ __ ,~~""'" -" " ,. = .,=,"""""""'''''"'''''''''',..., ~"", .. - o=''''"''*' ,""","'""'. ,-- ~-'-' _a~""",,,"~"·"";"i;;,-:;·; 
en 

L 

o 

o 

o 

'-o 

W 

<..:l 

Z 

CL 

~ 10-1 

c:r: 

w 

CD 

L 

::J 

z 10-2 

Figure R. 9.0 LRKESIDE/RLEWIFE 

10-3 

10-4• 

o; ..... '~'::.' C'~'-, ~' :-' " .. ,::::l.~;:~"-~::~,"~::"-cc~ ! ! ! !! !! I I! t! __ ,""-cc,"-,"" ! I !! __ ," __ ,"Jl~," ,A", __ ,""-,"""~l.c !!iI' . . 'Ind 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

m 

L 

o 

o 

o 

'-o 

W 

<..:l 

Z 

CL 

~ 10-1 

c:r: 

w 

CD 

L 

::J 

z 10-2 

Figure R.10.o ORK CREEK/RLEWIFE 

10-4• " !, !! !" , I , , , I I II 'I II II II " II "I' IlIU 365 

o 

JRN FEB MAR RPR MRY JUN JUL RUG 5EP OCT NOV DEC 

101 
~ 

o 

o 

o 

...... 

o 

w 

t:) 

z 

...... 

(L 

~ 10-1 

a: 

w 

CD 

~ 

:::J 

z 10-2 

10-3 

Figure R.ll.o WRUKEGRN/RLEWIFE 

10-4o • W..! ! M'W ! NWIW ! ! ! ! ! , ! ! , ! 

~ 

o 

o 

o 

...... 

...... 

o 

w 

t:) 

z 

...... 

(L 

~ 10-1 

a: 

w 

CD 

~ 

:::J 

z 10-2 

JAN FEB MAR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

Figure A.12.a STATELINE/RLEWIFE 

~I 

365 

10-41 _o 

, ___ ~-:':J: : ~'.'~:::-"-::;~"-::::W-~:;~"-~::-L"~,"~-L""-LJJ~,"l.ll~~~JlJi~~llI:~l' ! , I! !! !!!!! ! 1 , , , , ,4, , I+.+! 'LI ! W' dll I ,UU , __ , 'WnP 

JRN FEB MAR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

102 

~J'iii'¥!,..","""_~ • ~;g:>m., =.~ ~, ... , '4 =4"'· ~. ""'.~ "'~ "''''''",,''''''''''''no ; _ ,P>,..,''''''''''''''' "'~""""'= ',""d"~fo~"""'" , 
rn 

~ 

o 

o 

o 

"-o 

w 

Cl 

Z 

D--

~ 10-1 

a:: 

w 

CD 

~ 

~ 10-2 

Figure A.13.o MITCHELL/ALEWIFE 

10-41 .1.. .1, ,L 

O 

. . I I ) II! I ! J t ! ! ! I I! 'I!! t ! ! !!!!! I! I ,U I ! Ill, ! 1 'I! t! !! 1 J 

en 

~ 

o 

o 

o 

...... 

"-o 

w 

Cl 

Z 

D--

~ 10-1 

a:: 

w 

CD 

~ 

::::J 

z 10-2 

365 

JRN FEB MRR APR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure A.14.o CRMPBELL/RLEWIFE 

I L W J! 11 111 11 II ILl'11 III II I!~ 1 0 -4 .. , , .. • 1 365 

o 

JRN FEB MRR APR MAl JUN JUL AUG SEP OCT NOV DEC 

103 
'" L 

o 

o 

o 

"-o 

w 

C) 

z 

(L 

~ 10-1 

rr: 

w 

CD 

L 

:::J 

z 10-2 

Figure A.15.o PALISADES/ALEWIFE 

10 -Iii o "I I "." ,I I I, ! ",I! I ! .. I I W I! I! ~"""'...J!_!I...J...! I -LI.II ! ! ! ! I! J !!! ~,-,-..w....L.il.U.u! ...LII.I,I .. I ..... ' ... '.. 1 ... ' ................. ! ! 1 11 ,I! h ...... ! ( -0 ~ 

'" L 

o 

o 

o 

"-o 

w 

C) 

z 

(L 

~ 10-1 

rr: 

w 

CD 

L 

:::J 

z 10-2 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

Figure R.16.o BIG RoCK/RLEWIFE 

1O-1l! o I' , , I I I I ! ! !! !! !,! I : !,!! J.! II !! !! 1!!II!'4+' , ! ! !! !,!!! t ! d, !! I!! ! ! ! I! ! 

365 

JRN FEB MRR RPR MRI JUN JUL AUG SEP OCT NOV DEC 

104 

'>F"~"'" '" r'c'~ __ C"_ .,~'" ._,,,",,,,,,,~"''''=''_'"'''''"' - k=_~ '""''''¥' ,'" '-"'" """"",~,;X;",""",*,"":;>""-"o. 
co 

L 

o 

o 

o 

.-I 

"-o 

w 

C) 

z 

(L 

~ 10-1 

IT: 

W 

en 

L 

::J 

z: 10-2 

10-14o '_ ......... -, --~, ~,~~~ I 

Figure A. l.b ZION/SMELT 

! til ,/, ,'II ,1./,] _, ,U, J 

_ I I 1 ! ! I 

JRN FEB MRR RPR MRI JUN JUL RUG 5EP OCT NOV DEC 

365 

Figure R. 2.b D.C.COOK/SMELT 

l03E1 j i I I) j j I j [ Iii iii iii iii til t i , i I Iii iii 1 I [3 

(Tl 

;;:: 

o 

o 

o 

"-o 

w 

C) 

z: 

>--< 

(L 

~ 10- 1 

rr: 

w 

en 

L 

::J 

z: 10-2 

10 -l!U' 1 UUU ~ iIl.iJ Wid IIJ\iUU llULUIlJ ,I, , , , , , , ,jI , , , 'I" I II! ! 1'4111111 114 '" ij I I I I I I I I I I I I I ' I I I I , , , I I II 365 

o 

JRN FEB MRR RPR MRI JUN JUL RUG 5EP OCT NOV DEC 

105 
(Y) 

::;: 

o 

o 

o 

"-o 

w 

l:) 

Z 

D--

~ 10- 1 

a: 

w 

en 

::;: 

:::J 

z 10-2 

10-3 

Figure R. 3.b BRILLY/SMELT 

10 -411.o-+J,U o :W:I, I I ,j :ll: : : LH I, , , ,I ! ! ! ! 1 ! d! ! ! ! I ! ! ) ! !, ! I' I ! I :/'\! ! 1 , ! ! I! ! I! ! ! I! ! I ! ! ! ! Ii! til I 

365 

en 

::;: 

o 

o 

o 

"-o 

w 

l:) 

Z 

D--

~ 10- 1 

a: 

w 

en 

::;: 

:::J 

z 10-2 

JRN FEB MRR RPR MRl JUN JUL RUG SEP OCT NOV DEC 

Figure R. ij.b MICH CITY/SMELT 

10-41

o-~::~d:~hl~:U~:~ .,4 ! ~£:l: !! ~::~~~~~~~~~~~~~~wc~~~~l.~ .I! ! J I d! ! I I 

. !! ! ! ,! !! ! I t I! 

.. ' !LyLLH 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

106 
(T1 

E 

o 

o 

o 

"-

o 

w 

C) 

z 

(L 

~ 10- 1 

a:: 

W 

tD 

E 

::::l 

z 10-2 

Figure A. 5.b PULLIRM/SMELT 

10-41 "" ! I I ! ! o '"" 'W ! iJ, ! I ! ! I. !! ! ! ! ! ! ! 1 ! ddt ! ! ! ! ! ! ! ! I ! ! I I!: ! ! ! ! J ! !!I!!I,W 

365 

(T1 

E 

o 

o 

o 

"-o 

w 

C) 

z 

(L 

~ 10-1 

a:: 

w 

tD 

E 

::::l 

z 10-2 

JAN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R. G.b KEWRUNEE/SMELT 

10-4\ , ,l.I,.L '4-H' ,II, , ti, '~~5 

o 

JAN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

107 
Figure R. 7.b POINT BERCH/SMELT 

10 31= iii , i I Iii i I Iii i i r til iii til iii iii i i=i 

(T] 

:::i: 

o 

o 

o 

'-o 

w 

C) 

z 

(L 

102 

~ 10-1 

a: 

w 

CD 

:::i: 

::J 

z 10-2 

10-3 

lO-l!· o~~~~-L~-L~~'~I! .. J-Jlu.al.~!-L~-L~~-L! ! ! ! ! ! 

en 

:::i: 

o 

o 

o 

'-o 

w 

C) 

z 

(L 

~ 10-1 

a: 

w 

CD 

:::i: 

::J 

z 10-2 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R. B.b PORT WRSH/SMELT 

! I 

365 

10-1.11 U! !~~5 o 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

108 
'" ::E 

o 

o 

o 

"-

o 

w 

C) 

z 

(L 

;,:: 10- 1 

IT: 

W 

aJ 

;,:: 

:::::J 

z 10-2 

Figure R. 9.b LRKESIDE/SMELT 

! 4p II! 11 II !I!! d!!!111,d, III! lO-tll ! !! !', ,I, " ! ! ! !! !, " , ! 365 

o 

'" ::E 

o 

(:) 

o 

"-o 

w 

C) 

Z 

r-< 

(L 

~ 10-1 

IT: 

W 

aJ 

;,:: 

:::::J 

z 10-2 

JAN FEB MRR RPR MRI JUN JUL AUG SEP OCT NOV DEC 

Figure R. lO.b ORK CREEK/SMELT 

III I! I lOlh 

l 365 o 

JAN FEB MRR RPR MRI JUN JUL AUG SEP OCT NOV DEC 

109 
en 

L 

o 

o 

o 

"- o 

W 

t.:J 

Z 

0.... 

~ 10- 1 

a: 

w 

m 

L 

~ 10-2 

Figure A.l1.b WAUKEGAN/SMELT 

10 -4, o H' '* 1 ! I' I! ! 1 YUt y 11, !~ !! ! ! I ~! liM! X! !WI 

365 

en 

L 

o 

o 

o 

"-o 

W 

t.:J 

Z 

0.... 

~ 10- 1 

a: 

w 

m 

L 

:::J 

z 10-2 

JAN FEB MRR APR MRY JUN JUL RUG SEP OCT NOV DEC 

Figure R.12.b STATELINE/SMELT 

:I U L...i.I1! t! !!! I I! II, ! ! II,!! I ! 1 9 10-41 ! t '1L.l'!1,-+1' III 4! 1M!!! I ijiJ,;b+l"'! hY'! 365 

o 

JAN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

110 

'¥""'" '~"_;;;;;W_""""~_~.J:QJ;i'i~""ia"""''*~''':;h'~_~" ,,_ ,~~W",4""~ c __ "",""J4_;,q;;;o;; :c £e M;;~~ '"~-''f''''' ~"""'""=';;"'''¥4'''M"",,='''''''''''''*''' ."'~~_;, "."'--""'_"'\~"" 
I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

(Y] 10 1 ::E: 

0 

0 

0 

.--< 

"-

0 

w 

Cl 

:z: 

(L 

~ 10- 1 

0:: 

W 

ill 

::E: 

::::J 

:z: 10-2 

Figure A.13.b MITCHELL/SMELT 

L,yl !J.I.,l ! 111! I: ! 111 di, 4..1 Ur 1,wl! I! I ! ! I: [111 10-41 d!, I, ,I I I I ! bllU W '\w1!!' ! 365 

o 

(Y] 

::E: 

o 

o 

o 

"-o 

w 

Cl 

:z: 

(L 

~ 10-1 

0:: 

w 

ill 

::E: 

~ 10-2 

JAN FEB MRR RPR MRI JUN JUL AUG SEP OCT NOV DEC 

Figure R.14.b CRMPBELL/SMELT 

! ! ! !! :Ij lO-l

l! o !! ! 1 !6J1!!!!!l! ! !! d!! I:I! I: ! I ! 1 ! ! !: !:I!" :1, U!'Wn!!!rI I!/IUIU!!I 

365 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

111 
en 

:::E 

o 

o 

o 

...... 

"-

o 

w 

C) 

z 

>-< 

D-

:::E 10-1 

rr:: 

w 

(IJ 

:::E 

~ lO-2 

Figure R. 1S.b PRLISRDES/SMELT 

10-4o • I I I I ! ". I! I! :lilly ", ! .'! ! .1! I ! ! ! ! ! ! ! :1, \ ! !! !! !! !!! !! I! 

en 

:::E 

o 

o 

o 

"-o 

w 

C) 

Z 

D-

~ lO-1 

rr:: 

w 

(IJ 

:::E 

~ 10-2 

365 

JRN FEB MRR RPR MRT JUN JUL RUG SEP OCT NOV DEC 

Figure R.16.b BIG ROCK/SMELT 

II :1 I ! ! I lO-4' I! 365 

o 

JRN FEB MRR RPR MRT JUN JUL RUG SEP OCT NOV DEC 

112 

"~"'#1;:;'l;",,~ ... MW"' __ """"M"i",~=*'''''''~'''''~'''' _~":;:""_"""I\!ijQifiO,""""'""*,,,,~;::k;;; 4 &_ ............... """"""' .... _*, ""';:;:: "'"""''''''HEW .""~'"''''''''""",,,,;P---Jl'''''' _'~\!Li>""'" ","~~"",-~,~-,,,,,,,~,"~~(,,,,,,~,-=,t~""~ 
en 

L 

o 

o 

o 

...... 

"- o 

w 

C) 

z 

(L 

~ 10- 1 

IT: 

W 

CD 

L 

::l 

z 10-2 

en 

L 

o 

o 

o 

"-o 

w 

C) 

z 

(L 

L 10- 1 

a:: 

w 

CD 

L 

::l 

z 10-2 

10-3 

Figure R. I.c lION/i. PERCH 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

Figure R. 2.c D.C.COOK/Y.PERCH 

10-4, I I I '!I~lw'll'4d' 

o----::::-.. :-,':Q"'Jll~!U~I~N:_'"~::JLJ[JI~I!~-"""Jl'"Jl'"""CC""-"~~~Jt~~ ", !l'14lI.bYIl !! ! 1 t !l!! I I I I I I hllh I --~~~~I~I~~I~I~ j I Ij I .. 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

113 
co 

:::E: 

o 

o 

o 

'-

o 

w 

c:J 

z 

>-< 

D--

~ to-I 

0:: 

W 

m 

:::E: 

:::::> 

z to-2 

Figure R. 3.c BRILLY/i.PERCH 

1. !!Y,WI 'WI'M!I' Ill! !lilll'! I 10-ljIH"H, 1'1 1"l+.M 1~1j"j.," 365 

o 

(Y) 

:::E: 

o 

o 

o 

'-o 

w 

o 

Z 

D--

~ to-I 

0:: 

W 

m 

:::E: 

:::::> 

z 10-2 

JAN FEB MRR RPR MAY JUN JUL AUG SEP OCT NOV DEC 

Figure A. 4.c MICH CITYIY.PERCH 

to-ljl ;-.... ~ .. ~!lUAA~ILL' o ~':-J.Ii 141~1 ~~J...J....I...J. !! ! L+.l ! , , ! ! ! !!, .!!!!L.HM.J I 

365 

JAN FEB MRR RPR MAY JUN JUL RUG SEP OCT NOV DEC 

114 

",~·,'",Q)I~\.-"""''''''''i''''M I\l";;&'-~"""''''':;W'''~ _ ""~,,~~;,,,,','B''''·~".'''''"~''""'''"'''''"·'''"''''''''''"'''''N'i'i",._* ~ 74 ;,QLiiW _&f""',""~.,,=W"-"'-"_ '-"""'"_ ,"~"""" _=-,,",,,,,,,",,,gfllil14l$llliA,qil",,*~,,,,",""'E"",","« 
~ 

o 

o 

o 

...... 

"'- o 

L1J 

C) 

Z 

CL 

~ 10-1 

a:: 

L1J 

a:J 

::E 

::::J 

z 10-2 

Figure R. S.c PULLIRM/Y.PERCH 

10-4

o~~71'~llllll , I I ~~ ! ! 11 !! !!! 

365 

JRN FEB MRR RPR MRY JUN JUL RUG 5EP OCT NOV DEC 

(Y) 

::E 

o 

o 

o 

...... 

"'- o 

L1J 

C) 

Z 

CL 

~ 10- 1 

a:: 

L1J 

a:J 

::E 

::::J 

z 10-2 

Figure R. 6.c KEWRUNEEIY.PERCH 

10-lj'~!.!.!:!" O 

",. 

:~!U"~ " ! ! ::--:::-~:-~~.J~~~~j[~JlU1.lL..J~1rrr:~~ ! ! ! ! ! ! ! ! I. .J _W1'! .1. U, _, ill! r I! j . .J 1HaIb! ! ! ! ij, L1 W ','!' I ,I,! II U U 'lW,!!,WU 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

115 
'" ::E 

o 

o 

o 

...... 

...... 

Cl 

W 

CJ 

Z 

0-

~ 10- 1 

a: 

w 

CD 

::E 

:::l 

z 10-2 

10-4' o ! I , 0: !! ! "bJ ! ! I I ! 

Figure R. 7.c POINT BERCH/i. PERCH 

! 11 4l!1±1 t1! ! ! ! :I!! ! :I! ! ! .., ! 1hltl! I II !I ! 'H!ldJY'i+.4 WI! M! :1 ! 

JRN FEB MRR RPR MRi JUN JUL RUG SEP OCT NOV DEC 

365 

Figure R. S.c PORT ~RSH/i.PERCH 

10

9

." """""'" """""""'" '" 

'i: 

o 

o 

o 

...... 

Cl 

W 

CJ 

Z 

....... 

0-

~ 10-1 

a: 

w 

CD 

::E 

:::l 

z 10-2 

10-1.11 • """. • ::',111 '4.+.!U' u! 11'4,rII' 'I ~ 'I' 'I 'I"W 'lL.l HI I I UPI III' "'!II1r±dI'i~5 

a 

JRN FEB MRR RPR MRi JUN JUL RUG SEP OCT NOV DEC 

116 

--- -~.~,~"~-,\"W4"'liWiiI"#""o _"=+",_>,*,,,,,,"_p.~~,,:;:;C~=!,O;;P¥,p;lJbtzj,~lM_"=''i-'+'''Q'''''''''''-'__ ~~~ , "'''''''''''' "'-=-" -~.r->"'~" > ''''''4;PW~~1'~ "-'< 
103 

102 

'i: 10 

o 

o 

o 

...--< 

2J 10° w 

C) 

z 

>-< 

0.... 

~ 10-

0:: 

W 

(D 

::E 

::::J 

z 10-2 

Figure A. 9.c LAKESIDE/i. PERCH 

. 

10-3 

10-4 ~""""" ,w, '''''''' ~ o 

en 

::E 

o 

o 

o 

o " w 

C) 

Z 

0.... 

::E 10-1 

0:: 

W 

(D 

::E 

::::J 

z 10-2 

365 

JRN FEB MRR RPR MRr JUN JUL RUG SEP OCT NOV DEC 

Figure R.10.c ORK CREEK/r.PERCH 

10-4, ! ,lJ.....IJ 

_ o ____ ~!W~!W'!.! .. ~~ II I I 'O!! ll! ~ t 

.. ' __ tAA::!':!:!.c! ~' ::~J.-:~.L .. .l.Ll..LJ!LLjjJ..ll. .......... ~J: .. lJ ! :I" ,!!! •• I • I !! lL.l! L.J..Jl _1411'4 IL+JI'!!!" I I I ! I ! , 41!! u" ,m 

365 

JRN FEB MRR RPR MRr JUN JUL RUG SEP OCT NOV DEC 

117 
(T1 

:::E: 

o 

o 

o 

"-o 

w 

o 

Z 

0-

~ 10- 1 

0:: 

W 

m 

:::E: 

:::J 

z 10-2 

Figure R.ll.c WRUKEGRN/i.PERCH 

10-l!U W ", W 

O 

u , ,w,ly! M 1 ! LH ! ,J,!, ! ! , ! 1 ! I ,I ! lwJ1 k.J ! 1J .. ,I, I j 1 \ ! 4,,11 ,)! 11 Iii: ., ! ! ,\, ! J 

(T1 

:::E: 

o 

o 

o 

.--< 

"-o 

w 

o 

Z 

0-

~ 10- 1 

0:: 

W 

m 

:::E: 

:::J 

z 10-2 

:JG5 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

Figure R.12.c STRTELINE/i.PERCH 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

118 
(r) 

E 

o 

o 

o 

"-o 

W 

LJ 

Z 

(L 

E 10-1 

a:: 

w 

a:J 

E 

:::J 

z 10-2 

Figure A.13.c MITCHELL/Y.PERCH 

10-LlL.J,U o L1 !!!!!!I,U ! U4.i, ,J! ! ! ! 1 ! ! ! ! ! ! ! ! I ! ! !, Ll ! J ! II ! t ! ! 1 I ! ! I 1M W tV! I ! ! ! ! 1 ! ! ! d4JL.J ' ld ' li ,U 

(r) 

E 

o 

o 

o 

.--< 

"-o 

W 

LJ 

Z 

(L 

~ 10-1 

a:: 

w 

a:J 

L 

:::J 

z 10-2 

365 

JAN FEB MRR APR MAY JUN JUL AUG SEP OCT NOV DEC 

Figure A.l~.c CRMPBELL/Y.PERCH 

I I f U \ I L.tl ~ I I. ,.' ,. ,'! ! I ! ! ! I \wit LJ -- ! .II ~ ! ! t d! ! ! ! ! ) ! 1 ! ! !! !! !! ! !! t ! 10 -Ll "'" , " '" , "'" 365 

o 

JAN FEB MAR RPR MAY JUN JUL AUG SEP OCT NOV DEC 

119 
'" ::E: 

o 

o 

o 

"-o 

W 

t::l 

Z 

0--< 

CL 

~ 10-1 

a:: 

w 

OJ 

::E: 

::::J 

z 10-2 

'" ::E: 

o 

o 

o 

"-o 

W 

t::l 

Z 

0--< 

CL 

~ 10-1 

a:: 

w 

OJ 

L 

::::J 

z 10-2 

Figure R.lS.c PRLISROES/Y.PERCH 

365 

JRN FEB MRR RPR MRY JUN JUL RUG 5EP OCT NOV DEC 

Figure R. 16.c BIG ROCK/Y.PERCH 

,I •• 1, I: ! 9 !ll III ,,! I! I 10-41 !WI • ! 365 

o 

JRN FEB MRR RPR MRY JUN JUL RUG 5EP OCT NOV DEC 

120 
(y), 

:L 

"-o 

w 

Z 

cr: 

0:::: 

rZ 

W 

0:::: 

w 

m 

:L 

::J 

Z 

(y) 

:L 

"- o 

w 

Z 

cr: 

0:::: 

rz 

w 

0:::: 

w 

m 

:L 

::J 

Z 

Figure R. 1.d ZION/RLEWIFE EGGS 

10-2o • ! , , , !! !! ! • 9 l' I ! ; j6 1 n! ! ! ! I ! I 

365 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R. 2.d D.C.CDOK/RLEWIFE EGGS 

10-2• 

o~"·'-:-:" ":;-:' 

" " ,,.,., 

~~~ ! 'u III! ,! !! t!! ! t ! 

365 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

121 
'" L 

'-o 

w 

z 

a: 

cr: 

IZ 

W 

a:: 

w 

o:J 

L 

:::J 

Z 

'" L 

'-o 

w 

:z 

a: 

cr: 

I-

:z 

w 

a:: 

w 

o:J 

L 

:::J 

:z 

Figure R. 3.d BRILLY/RLEWIFE EGGS 

10-~)'-" ~ ~~ __ w.~ .. .w .. __ ~.1~~~~~_l "I ! !l! ! ! ! I 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

365 

Figure R. 5.d PULLIRM/RLEWIFE EGGS 

10-2o . ! ! , I ! I! :/, ! ! , , ! ! 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

122 

", ~" ,"""i#il4i~l"If.i>'_~"" .. _'¥"="'~"_""'" ~~'iG",,"f4?-';nP', "*""""""_ ""''''' .. <ii ...... ''''' .. '''·'''''m "" "" ",14""" """""",,,,_.~,,,,,,, _ ,""""*' _,~ - '''',,&,,~ A~,""~· 4 ~='",'F""*'i''''''". "" .. ~'"* P;;;"'"''''"~ ,.,~:;;;;::g;::;;:x;:oj$~~ ~I~_ ~.",--~=~=~~~ 
0'1 

L 

"-0 

W 

Z 

IT 

a: 

fZ 

W 

a: 

w 

CO 

L 

:::J 

Z 

0'1 

L 

"-o 

w 

Z 

IT 

a: 

fz 

w 

a: 

w 

co 

L 

:::J 

Z 

Figure R. 6.d KEWRUNEE/RLEWIFE EGGS 

21 ' 6 t J , ,j, t J, I, I , , , , , , I 

10- , 365 o 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

Figure R. 7.d PT BERCH/RLEWIFE EGGS 

10-21 , , , , , 0' 

--~.~.:'~" -~'::~~:::-LL::::"-::;;""~~"~:1~ .. .1~""""""""OWLL,""-LL,"O" !!! t ,! , ! ! , ! 1 ,! I I I !!" h J 1,_ ,Al. I ! ,II I ,I .... d,, I !! I : ! II!! 1 ! I 1 ) I! 1 \ I t I ) I 

JRN FEB MAR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

365 

123 

-------
'" ::E 

"-o 

w 

z 

a:: 

0: 

f--

Z 

W 

0: 

W 

m 

::E 

:::J 

Z 

Figure A. B.d PDAT WASH/ALEWIFE EGGS 

2 I a 4 ", I! 1 I I I 1 0 - I I 365 o 

'" ::E 

"-o 

w 

z 

a:: 

0: 

f--

Z 

W 

0: 

W 

m 

::E 

:::J 

Z 

JAN FEB MAA APA MAl JUN JUL AUG SEP OCT NOV DEC 

Figure R. 9.d LRKESIDE/RLEWIFE EGGS 

10-21 o ! ! I!! !! !! .I! ! t I !" *! ! ! ! I ! ! ! , ! ! , ! ! I 

::365 

JAN FEB MRA RPA MAl JUN JUL AUG SEP OCT NOV DEC 

124 

<_~""""""""'~='!tJ\liii!lQ};""", _ "" j~<~ _""_~,",""",,,, ""'"~K-"""",,,,,",,,,,~.-·,,,q~",,, ,~_ =""""; ",,,,,,,=,,,",,,,,,,,,0; HPi";>-""4~"",,,,..,,.,..~,,,:q,, §42 - ~,-, "" i4~i -, ... ~"""*"" i .J4d"""== =::w ;n;:z::;:::t¥ ,~",,""" • ,-,_~_~ ~"""'''''('''.~.,''''' -r_ '. 
(T] 

::E 

"'- o 

w 

z 

a: 

a: 

fz 

w 

a: 

w 

m 

::E 

~ 

Z 

(T] 

::E 

"'- o 

w 

z 

a: 

a: 

fZ 

W 

a: 

w 

CD 

::E 

~ 

Z 

Figure R.10.d ORK CREEK/RLEWIFE EGGS 

! k J' l' ! ! I 10-21 , 365 o 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

Figure R.11.d WRUKEGRN/RLEWIFE EGGS 

10-21 o 1 1 1 1 ! ! !!! , II, ! ! 'N" !! !, I! I! ! I ! I 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

125 
Figure R.12.d STRTELINE/RLEWIFE EGGS 

104.... i I I I Iii I iii iii I Iii Iii [ iii iii i [ iii iii 15 

103 

~ 102 

"- 0 

w 

Z 

IT 

0:: 

tZ 

W 

0:: 

W 

co 

L 

:::J 

Z 

10-~ 

o~----::::'"~::;;'"";::':-' "-:::;-"::::-L,"~::-L,"~,"-L",-"~","UC",-"",-"",-"""-"""",",-""-L" :/, I I '0' ! ! 

365 

'" L 

"-o 

w 

Z 

IT 

0:: 

tZ 

W 

0:: 

W 

CD 

L 

:::J 

Z 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

Figure R.13.d MITCHELL/RLEWIFE EGGS 

10-21 ,t, Il, 'W' '~~5 

o 

JAN FEB MAR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

126 

,G"",l:;;;;;;;;q,,,.WF,p;:;i:&ig,,, .. ¥Q,,,,$- "~""r," ",~,,,,,",,"",,,,,-."'" ",",,_ ",...;s::;-:--<"",,%"_"":w# M "~,"~J..~R¥~"""" _",orR,,- '-..,..-"'iiiR9l\W .... +~"'",~, ~.=&i'i'i¥>-m _e"'4" ""''' *"'* _,,*A' ~,_="W' ~"-;;; '" Oiliii&£,,,,"!;-- "'%4'< ,,--, , _1_' " ",;~.,,"~~~); ,," 
Figure A.14.d CAMPBELL/ALEWIFE EGGS 

10l!fi Iii iii' I Iii iii iii iii Iii iii Iii iii iii iii iii iii iii iii iii iii iii '3 

1031: -:: 

~ 1021:- "-0 

w 

z 

a: 

a: 

f- 10 lI=- z 

w 

a: 

w 

a:J 

L 

~ 1001: 

10-11=- -:: 

! 1 " !!! 10-21 ! 365 o 

JRN FEB MRR APR MAY JUN JUL AUG SEP OCT NOV DEC 

Figure R. lS.d PRLISRDES/RLEWIFE EGGS 

1041:: r I j iii, iii I I I iii I Iii iii iii iii I Iii Iii i I I I I I::J 

1031: -

'" 1 02 L 1=- "-0 

w 

z 

a: 

a: 10 1

1= f- -:: Z 

W 

a: 

w 

a:J 

L 

~ 100 z 1=- -:: 

10-11=- -

10-2o ' III !! ! ! ! , ! !" !! !!, I 

365 

JRN FEB MAR APR MRY JUN JUL AUG SEP OCT NOV DEC 

127 

------- --- -----------
Figure R.16.d BIG ROCK/RLEWIFE EGGS 

lOY ..... I i I I i j iii I I ill I Iii Iii i I I I Iii I I iii I I iii I I I i !i 

1 o 3 Ie- -, 

'" 10 2 Ie- ::E: 

"-0 

w 

Z 

IT 

a: 

f- 10 lie- z 

w 

a: 

w 

ro 

::E: 

::J 

z 1 ODielO-11e- -

lO-~ 

O-.... :::!~! .. ! -:!:!:-"~:::-"-::::"-::;;-"--:::""~:-"-.. """--""""""--""-""""-" 

" " " I! ! ! ! ! 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

128 
~ 

" o 

l1J 

Z 

cr: 

0: 

IZ 

l1J 

0: 

l1J 

II] 

~ 

~ 10-1 

Figure A. I.e ZION/ALEWIFE LRRVAE 

", l¥. ! ! I 

10-~ 365 o 

.., 

~ 

" o 

l1J 

Z 

cr: 

0: 

IZ 

l1J 

0: 

l1J 

II] 

~ 

~ 10-1 

JAN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure A. 2.e D.C.COOK/RLEWIFE LRRVRE 

10-3o • ! ! ! ! I! !! !, J ! , ! I! ! 1 '-Ii! !! I'! '.lbl' Wd,' ! I I II ' ,! !! I 

JAN FEB MRR RPR MAl JUN JUL RUG SEP OCT NOV DEC 

129 

365 
... 

L 

"-

o 

w 

Z 

0: 

a:: 

fz 

w 

a:: 

w 

CD 

L 

~ 10-1 

Figure R. 3.e BRILLY/RLEWIFE LRRVRE 

10-3• O .. ~~~·!·!~ ........ ~ .. ~ ........ ~.1~-L~J-~~t , II' .. ,! ! ! ~-'-U" U '...J..J.! 4zl'J..j\-M~~!I.I!.u .... ~ ........ ~ .... ;J I! ! 

... 

L 

"-o 

w 

Z 

0: 

a:: 

fz 

lL.J 

a:: 

w 

m 

L 

~ 10-1 

JRN FEB MRR RPR MRY JUN JUL RUG 5EP OCT NOV DEC 

Figure R. 5.e PULLIRM/RLEWIFE LRRVRE 

10-31 

O~~II II ~II ~...lL.. ............... !' ,!! t ! t, ." t I !!! ! ! ! I !! 

JRN FEB MRR RPR MRY JUN JUL RUG 5EP OCT NOV - DEC 

130 

365 

365 

'" I,". <?R_',"""'~' "~"_.,;, ,- -"~~:J7 .. ;g;:"l"'*=-:i0~"",'~~""l"""'f¥iii''iif,,*~'",, #,,4'~' ',,",,",,,, __ ""'''' ~i4' ;: _ ;;;i Q, -"""'~~ _" _< '+ """ Q;'§""i!lm1$54" "'"'" """""" _ "","'.:;;;"""","';::"0, ow, ~, ,. "o~¥_,~<{ '=!%i_-~""""'"L_."_r'~"'" 
'" :::E 

"'- o 

w 

Z 

IT 

n:: 

f--

z 

W 

cc 

W 

QJ 

:::E 

Figure R. 6.e KEWRUNEE/RLEW[FE LRRVAE 

~ 10-1 

'" :::E 

"'- o 

w 

Z 

IT 

cc 

f--

Z 

W 

cc 

w 

CD 

:::E 

, I, Ill!, !l! lily !~1 ! 1 I 

10-31 I 365 o 

JAN FEB MRR APR MAY JUN JUL RUG SEP OCT NOV DEC 

Figure R. 7.e PT BERCH/RLEW[FE LRRVAE 

~ 10-1 

10-31 o I I !! f! !!!! ! ! !' t" I! !!, I,e !!.,: h W ! 'YQ' ,I, ! !! ! I '! ! !! ! ! I 

365 

JAN FEB MAR RPR MAY JUN JUL RUG SEP OCT NOV DEC 

131 
'" L 

"- o 

w 

z 

a: 

0:: 

fZ 

W 

0:: 

W 

IT) 

L 

~ 10-1 

Figure R. 8.e PORT WRSH/RLEWIFE LRRVRE 

10-3

o • ' ! I! I I ! ! & ! -, ". ! ! ! ! 

'" L 

"-o 

w 

z 

a: 

0:: 

fZ 

W 

0:: 

W 

IT) 

L 

~ 10-1 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

• Figure R. 9.e LRKESIDE/RLEWIFE LRRVRE 

365 

! ,I 1O-31 ! I'! ;1 365 

o 

JRN FEB MAR APR MAl JUN JUL RUG SEP OCT NOV DEC 

132 

.," ~'_"4~!!iiit{,.i&4-,"",'"ur~ ... ~ ,_fn=i.\!t4i#,"'"",' :p;;::::;sL~,-," ~~ ,~""','~"'"~ 3· .~ kp., ~. ~, _'.'ift""f f [,,-_,,4"""" ~'"'_""* _ A ~=q;"","",,,,,,,, =:""_""'''''~="''''''''"'¥. "_"'''", __ 
(Y) 

:>:: 

"-o 

w 

Z 

IT 

a: 

fz 

w 

a: 

w 

ID 

:>:: 

~ 10- 1 

Figure A.I0.e OAK CREEK/RLEWIFE LARVAE 

I" ,WI " It',., ! I I 10-31 365 o 

'" :>:: 

"-o 

w 

Z 

IT 

a: 

fz 

w 

a: 

w 

ill 

:>:: 

~ 10-1 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R.ll.e WRUKEGRN/RLEWIFE LRRVRE 

10-3, " 

o ----:::'"~::::'"'-:' ::':-' '"-:::;-.. :::: .... ~~"- 1 ' " , , .. ~'"JI:.-L'"wc~wc'"WC""WC~wc"-'"-L'"-L,,-L' " ! I ! ! I I 

365 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

133 
'" :L 

'-. 

o 

W 

Z 

IT 

a:: 

Iz 

w 

a:: 

w 

CD 

:L 

~ 10-1 

Figure R.12.e STRTELINE/RLEWIFE LRRVRE 

10-31 o 1 1 ! !! !!! " II, " ilW ! Ilk II! ! ! n,! ! I !! !!! I 

365 

'" :L 

'-. 

o 

W 

Z 

IT 

a:: 

Iz 

w 

a:: 

w 

CD 

::E 

~ 10-1 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Fi9ure R. 13.e MITCHELL/RLEWIFE LRRVRE 

! • .., Y' Y ! 1\ I ! I 10-31 1 365 o 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

134 
Figure R. 14.e CRMPBELL/RLEWIFE LRRVRE 

103 EI I I iii i I I I I I I iii f I I I I iii I i I I i I I I I , i I I I I , i I I I i I I I I Iii i I I i I I I I ..... 

102l:-- -:= 

'" 10 1 L 1= - "- 0 

L1.J 

Z 

([ 

a:: 10°1=- f--

z 

w 

a:: 

w 

co 

L 

~ 10-11=- -:= 

'" L 

"- o 

L1.J 

Z 

([ 

a:: 

f--

z 

w 

a:: 

L1.J 

co 

L 

10-2l:-- -:= 

10-3, o I I !! ! !! I!! ! !! ! t! t, I' , ! t! !: !! I 

365 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R.15.e PRLISRDES/RLEWIFE LRRVRE 

~ 10-1 

!: !! !! I!'!!! !, !!! " t' !, ! I !!! 10-3• t .! t!! ! ! 365 

o 

JRN FEB MRR APR MAl JUN JUL RUG SEP OCT NOV DEC 

135 
Figure R. J6.e BIG ROCK/RLEWIFE LRRVRE 

1 03c iii iii iii iii iii iii iii iii iii iii iii iii i i '" 

102t :J 

'" L: --o! 

"'- 0 

llJ 

Z 

IT 

a: 

fz 

w 

cr: 

llJ 

fIl 

L: 

~ 10-11::-

10-21::- --= 

10-3' o ! ! ! ! 

!! ! ! ! ! 

365 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

136 

-<''''_;;:>7~~¥4,-"",..",~o"",_","~,D''"""= __ 4!'=" __ ''''',,,~", """"*"""""'~~"-~-, ",,=;r"'r,J'7~~~' =*',,-,-'f4'l"\9I"- $_ iji$i .,,-- ,~¥,c"_",",, 
~ 10-1 

"-o 

w 

z 

a: 

0:: 

~ 10-2 

w 

0:: 

W 

co 

::;: 

~ 10-3 

Figure R. 1.f ZION/SMELT EGGS 

! I ! ! I 10-51 ! ! ! 365 

o 

~ 10-1 

"-o 

w 

z 

....... 

a: 

0:: 

~ 10-2 

w 

0:: 

W 

co 

::;: 

~ 10-3 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R. 2.f D.C.COOK/SMELT EGGS 

: ! I 

10-50 ! 365 o 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

137 

~~~~~-- ------- ------
10 1 

10° 

~ 10- "-o 

w 

z 

a:: 

w 

o::J 

L 

~ 10-3 

10-lJ, 

10-5 

o 

~ 10- 1 

"- o 

w 

z 

a: 

a:: 

~ 10-2 

w 

a:: 

w 

o::J 

L 

~ 10-3 

Figure A. 3.f BAILLY/SMELT EGGS I I I I I Ii r I 1 1 I I r I I ITTII 

_.1 J l. I I J I I I 

JAN FEB MAR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R. 5.f PULLIAM/SMELT EGGS 

10-51 

, o~""-~::Le~-:':;' Le'";' :::-,1-:::;-J.:::: .... ~:: ................ __ '"-'""-'""-'"-UC""Le"-Le"-LeJ-, q "I, 'I' .,. ! I 

JAN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

138 

365 

365 

<, -~-T.dt-"iiWQ"'''''Ri'i>i"' - ~"CC_~,~=~2l.'-.""".,.""<i4,G,j.-_"'''''''''''"''"'''' ..... -''''''''''''''I''Jf ;g~"""""'''',..'*';fJ''''';;::,''''''''1,.."'''*'N'= ¢ ¢ Z ; "",,,",,'''' ~_=..,"~~, ~""Z "';;or.,""" __ ","",,, p::m;;:::;m,i<;o:u...b3iiii#!ffi;;: "'''''''''''''''''" =~"'-'~.k'_,,,,_ 
10 1 

10 

~ 10-

o " w 

z 

a: 

a:: !z lOw 

a:: 

w 

CD 

~ 

~ 10-3 

1O-l! 

10-5 

o 

Figure R. 6.f KEWRUNEE/SMELT EGGS 

-

-

-

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

Figure R. 7.f PT BERCH/SMELT EGGS 

lOiC! Iii I Iii iii I iii iii Iii i I I I iii I I iii Iii iii I i 1:1 

10°1-- --:J 

~ 1O-1k-- -

0 

w 

z 

a: 

a:: !z 10-21- --= 

w 

a:: 

w 

CD 

~ 

::J z 1O-3b- -

10 -l!1-- --:J 

! t! t 1 ! I !, I I ,! !, !! ! I I 10-51 ! ! ! ! ! ! ! 365 

o 

JAN FEB MAR APR MRY JUN JUL AUG SEP OCT NOV DEC 

139 
'i: 10- 1 

o " llJ 

z 

a: 

a::: 

~ 10-2 

llJ 

a::: 

llJ 

o:J 

::E 

~ 10-3 

Figure R. 8.f PORT WRSH/SMELT EGGS 

10-51 , 

0----::::"""-;' ;':-""'";' :::-""-:::~""::::l. .. :::: .... ~:-.......................... "-,""-,""-,""-, , ,1'1 I I II I! ! 

365 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R. 9.f LAKESIDE/SMELT EGGS 

lOlci I I I I Iii iii iii j I Iii Iii i ( I Iii iii iii I 13 

10°\- --::J 

'i: 10-16-

0 " 

llJ 

Z 

a: 

g: 10-210- z --:: 

llJ 

a::: 

llJ 

o:J 

::E 

~ 10-310- -

10 -LlIc- --= 

! ! I 

10-51 I 365 o 

JRN FEB MAR APR MAl JUN JUL AUG SEP OCT NOV DEC 

140 
Figure R.I0.f ORK CREEK/SMELT EGGS 

101 .... 1 I j , Iii I iii iii iii iii iii Iii Iii I I I Iii i r I iii i i t i , i=i 

100b--

'i: 10-11=- "- 0 

w 

Z 

IT 

g: 1O-2b-- z 

w 

a:: 

w ~ o:J 

::;:: 

~ 10-3b--

10 -l!b--

10-5 

'i: 10-1 

"-o 

w 

Z 

>-0 

IT 

a:: !z 10-2 

w 

a:: 

w 

o:J 

::;:: 

~ 10-3 

0 

JAN FEB MRR 

10-51 _ ...... ..J...I...J-JI o I I 

It 

, l. 

I I 

RPR MAY JUN JUL AUG SEP OCT NOV DEC 

Figure A. 11. f WAUKEGRN/SMELT EGGS 

t! .I! 

, ! ! I I 

JAN FEB MRR APR MRY JUN JUL AUG SEP OCT NOV DEC 

141 

-

-: 

365 

365 
1: 10- 1 

"-o 

ILl 

Z 

IT 

0:: 'Z 10-2 

ILl 

0:: 

ILl 

a:J 

L 

::::J z 10-3 

Figure R.12.f STRTELINE/SMELT EGGS 

10-51 o !! ! ! 'LA! II ! ! 

365 

1: 10-1 

"- o 

ILl 

Z 

IT 

0:: 'Z 10-2 

ILl 

0:: 

ILl 

a:J 

L 

~ 10-3 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R.13.f MITCHELL/SMELT EGGS 

! ! I 10 -51 1 ! !! 365 

o 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

142 

~, "","-fri?4~;;O~;:;, .. ,,9~)""_" _;-~ @iii!QJ i; _ "." , e_, .- ,''''',-~ ~9""_iili """"'"'<pc'"'" '~"''-'~''-<,""" -,_- .~ __ ¥;j'i"o;""Ti'·'-C-'~ 
~ 10- 1 

"-o 

w 

Z 

0-< 

a: 

a: 

~ 10-2 

w 

a: 

w 

a:J 

::E 

~ 10-3 

Figure A.l~.f CAMPBELL/SMELT EGGS 

! I ! 10-5• , ,e ,", , , 365 

o 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R.lS.f PRLISRDES/SMELT EGGS 

10 1 ..... iii I iii I I , i I I i j Iii j i , I I I i I Iii iii i i j , i I I Iii I iii iii I I I I I I I I I i =i 

10°1::-

~ 10- 11=- -:: 

"- 0 

W 

z 

a: 

g: 10-21=- z 

w 

a: 

w 

a:J 

::E 

~ 10-31=- -:: 

1O-11l: -:: 

!! !,! t " ,! : , I 10-5' , , 365 o 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

143 
Figure R. 1G.f BIG ROCK/SMELT EGGS 

10 1 ..... 1 iii I I Iii I Iii iii! I j i [ \ iii iii iii iii i i:::J 

~ 10- 1 

"-o 

w 

Z 

IT 

a:: !z: 10-2 

w 

a:: 

w 

co 

L 

~ 10-3 

10 -51 

o~""::::---:::~"::::IJ'~ ~':I!::"~::~---:~:-"~"--"""""""""""""""""""" I' " II! !! !! 1 ! !! ! 

365 

JRN FEB MRR RPR MRY JUN JUL RUG 5EP OCT NOV DEC 

144 

'~I,~~""""i4i444'4l!",g, ".~"",...~""~"L!!,:!@!@ ill !Ii ~ii j f¥$l::;¥,,,,;;;r,,,,,,, , ,~'J .~."<~_"' ~,.,~, ~ ~ __ ."""'~ , __ "~.,...,a","- .""'" j __ ,,,,,,_'4£' '~'~_A"._,,"%~~""~""'_ ",n:;: "''"''''"''''''''"'"''''''- '''''''*'" 4J =..,_,.."u~~._~_ -~.,.~,&.~;;C:;;>~"-<}j;~,."..~_-\4ii 
en 

::E 

"-o 

w 

z 

a: 

~ 

~ 10-1 

w 

~ 

W 

a:J 

::E 

~ 10-2 

figure A. l.g ZION/SMELT LARVAE 

I " t! t, I t I I! J 10-4 I I I ! I 365 

o 

102 

10 

~ 10° "- o 

w 

z 

...... 

a: 

0: 

~ 10-1 

w 

~ 

w 

ro 

::E 

~ 10-2 

10-3 

1O-11 

o 

JRN FEB MAR APR MAl JUN JUL RUG SEP OCT NOV DEC 

Figure A. 2.g D.C.COOK/SMELT LRRVAE 

-

-

-

-

-::l 

~ 

l 

--

~ -j 

::I 

~ 365 

JAN FEB MAR APR MAl JUN JUL AUG SEP OCT NOV DEC 

145 
102 

IT) 

L 

"-o 

I.LJ 

Z 

10 

IT 

a: 

~ 10-1 

I.LJ 

a: 

I.LJ 

co 

L 

~ 10-2 

10-3 

'" L 

"- o 

I.LJ 

Z 

10-

IT 

a: 

~ 10- 1 

I.LJ 

a: 

I.LJ 

co 

L 

~ 10-2 

o 

Figure A. 3.g BAILLY/SMELT LARVAE 

JAN FEB MRR APR MAY JUN JUL RUG SEP OCT NOV DEC 

Figure A. 5.g PULLIAM/SMELT LRRVRE 

10-4

o ' • ! ! r ! I: ! ! ! ! ! ! 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

146 

365 

365 

"",.,-Yo '-'<'4t"~~"""'ijiI1if.%_~~--..a-,,-"""., ." _"_",;c::;t£t£;. §iC~ .fiZ JQ2i\$; n ; ;$_ :.A ;:;;; ~ _,",'<n""'kb ~-_"~ v"""~ "","-','~Ib'>'n'"'''' 
102 

10 

~ 10° "-o 

w 

z 

a: 

0:: !Z lOw 

0:: 

W 

CD 

L 

~ 10-2 

~ 

"-o 

w 

z 

10-3 

10-4 

o 

a: 

0:: !Z 10-1 

w 

0:: 

w 

CD 

L 

~ 10-2 

Figure R. 6.g KEWRUNEE/SMELT LRRVRE 

I I I ! I I I r I I I I I I I f I I I I I I I I I I 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R. 7.9 PT BERCH/SMELT LRRVRE 

10-4• I I I o ! 11 !! !!! !!! ! , !! !! :II! 'I' f! ! 11! ! !l! 1 ! 1+1! 1 f I ! ! 

JRN FEB MRR RPR MRr JUN JUL RUG SEP OCT NOV DEC 

147 

-

-

-

-

--" 

, 

~ 

,,1 

365 

! I 

365 
'" L 

"-o 

w 

Z 

Figure R. 8.g PORT WRSH/SMEL1 LRRVRE 

IT 

a: 

~ 10-1 

w 

a: 

w 

m 

L 

~ 10-2 

lO-LlI~'=' o 7:::-:--:-~LL~~ I!! ! 

! : 'N Ill, 14+'1 ! ! ! I 

365 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

Figure R. 9.g LAKESIDE/SMELT LARVAE 

1 02 .... iii i I I I Iii iii iii I Iii I I iii Iii iii I I I Iii iii iii iii iii iii ii' iii Iii j i =i 

1011: -= 

~ 1001: "-0 

w 

z 

a: 

g: 10-11=- --:: 

z 

w 

a: 

w 

m 

L 

~ 10-21= 

10-31::-- --:: 

10-41 , , 

o ----:;:'"~~' :'::-""':': ::,""-:::;"",::~ .. "::::-.. -::-............................ "" .. ""-","" , ! ! I I! " II " "" " 

! ! ! 1 ! 

365 

JAN FEB MRR RPR MRI JUN JUL RUG SEP OC1 NOV DEC 

148 

< '"'·'i~~"-- ~,~"'''~ - - ~~""" "'~~~"'<~"""'''~_.lif ... * ;;;;; :;;:dld,,~ cp",' 
'" ::E 

"-o 

w 

z 

a: 

a: 

~ 10-1 

w 

a: 

w 

c:o 

::E 

~ 10-2 

Figure R.10'9 ORK CREEK/SMELT LRRVRE 

10-41 o , ! I ! ! 1 ! ! I ! I 

~'~" _ :' • :' I :",1 ! ',' ~' • :.l.J.:~J:~l~~~~~~~UULJ~~~~~~~, , , ! i • J ' h , ' , ' :!' , . L ,I, ! I ! ! I ! ! ! ! ! I J ! 1 L'! I 111 ! ! • ! !! ! t! ! I 

365 

'" ::E 

"-o 

w 

Z 

0---< 

a: 

a: 

~ 10-1 

w 

a: 

w 

c:o 

::E 

~ 10-2 

JAN FEB MRR RPR MRI JUN JUL AUG SEP OCT NOV DEC 

Figure A.11.g WAUKEGAN/SMELT LARVAE 

1 a I I I I I , "" "I -4 ! ! I ! ! ! ! ! I' !! ! I l: 365 . 0 

JRN FEB MRR RPR MRI JUN JUL AUG SEP OCT NOV DEC 

149 
CT1 

~ 

...... 

o 

w 

z 

([ 

a: !z 10-1 

w 

a: 

w 

ro 

~ 

~ 10-2 

Figure R.12.9 STRTELINE/SMELT LRRVRE 

10-41 

o ---~::~!! -~::;".!"!: :::-.. :::;.L~:::- ,I, J I I! .. -::::-.. 

" 

~:-.1""I.""",""-L,""-,"""-L""-L""-L,""-L: ,,/ II I" , I! , ! 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

'" ~ 

...... 

o 

w 

Z 

([ 

a: !z 10-1 

w 

a: 

w 

ro 

~ 

~ 10-2 

Figure R.13.g MITCHELL/SMELT LRRVRE 

10-41 , ". ""y, dr! ~IW ! 11 1 "' 365 

o 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

150 

~'" ""_l __ ¥~_~"~_,'u" ,,~. '¥M1_"'" _#"'" ,~",,,,_,,,", _+~ " .h .~ ______________ ~ 
Figure R.14.9 CRMPBELL/SMELT LRRVAE 102~i I I 'I I I , I i I Iii I i I I Iii I iii Iii iii iii I I I iii iii Iii 14 

10 11= -

'" 10°1=-- L 

"- 0 

lLJ 

Z 

a: 

g:: la-lI::- z -.: 

lLJ 

a:: 

lLJ 

III 

L 

~ 10-21::- -.: 

10-31= -

10-4a ' ! ! ! I! !! ! ! I ! 1 !! I I I ! ! ! I ! ! ! I ! ! I!! I! I !! I ! !! 1 !! ! I I ! ! ! ! I ! !! !!! 1 I ! J 

"" :::E 

"-o 

lLJ 

Z 

...-. 

a: 

a:: !Z 10-1 

lLJ 

a:: 

lLJ 

III 

:::E 

~ 10-2 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

Figure R.15.9 PRLISRDES/SMELT LRRVRE 

1: ! !! !!!:!! t: , ! , : !, : ! I !! !! !, !!,!!!!,,!! !" I' ! !! I!!! 10-L

\I ! ! t !! !!!!! !!!! 365 

o 

JRN FEB MAR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

151 
Figure R.16.g BIG ROCK/SMELT LRRVRE 

102 ... Iii iii iii iii iii i , ii' iii I i I I I Iii iii iii I I Iii I I iii iii i:1 

101b- -:: 

'" L lODE - "- 0 

lJ.J 

Z 

....... 

IT 

g: 10-11=- -:: Z 

lJ.J 

a:: 

lJ.J 

CD 

L 

~ 10-21=- -:: 

10-31=- -:: 

I! ! 10-4

• ! 365 o 

JRN FEB MRR RPR MRI JUN JUL RUG SEP OCT NOV DEC 

152 

M""~"C,,"~,,"'"l"i>4R '''''''''''''''';;;'~~~'~'~'''~'~F ,$ ''"C ~,~,_,j!iq ,, __ , rQ"""'_44,,,",,,.fR"'9\iii<i_"''' "=, ,_,r""'~~"~'" 
C'1 

::E 

"-

o 

w 

z 

a: 

0:: !z: 10- 1 

w 

0:: 

W 

(0 

::E 

~ 10-2 

Figure A. 2.h D.C.COOK/i.PERCH EGGS 

t. ! I I 10 - 41 I I I I I, I I 365 

o 

JRN FEB MRR RPR MRi JUN JUL RUG SEP OCT NOV DEC 

Figure R. 3.h BRILLY/i.PERCH EGGS 

102Ft I i I I I 1 Iii Iii I , iii iiI i I I I I Iii I I I ! iii Iii I I l=i 

1011::--

~ lODE- "- 0 

w 

z 

a: 

g: 10-11::- z 

w 

0:: 

W 

(0 

::E 

~ 10-21::- -:: 

1O-3E- -:: 

10-41 I I I I I , , , , , , :! I I , , I ' , , , , , , , , , , , , , , I , , , , , I I I ' , I ' I ' I ' , , I I ' , I ~65 

o 

JAN FEB MAR APR MAi IIIN JUL AUG SEP OCT NOV DEC 

153 
'" ::E: 

...... 

o 

w 

Z 

IT 

0:: 

~ 10- 1 

w 

0:: 

W 

CD 

::E: 

~ 10-2 

Figure R. S.h PULLIAM/Y.PERCH EGGS 

10-4o '-...... ' , ~,,~~~wL~ '1_'_ ~,~4~~,'~I~~ ______ ~~~~~-UW-W-~~~~~,: I I 

365 

JAN FEB MAR APR MRY JUN JUL AUG SEP OCT NOV DEC 

Figure R. S.h PORT WASH/Y.PERCH EGGS 

102 .... , iii i , iii iii Iii iii iii, , iii iii iii iii i I Iii I , i I I i I t I i 1=4 

10 11= -

~ 1001=- ...... 

0 

w 

Z 

IT 

0:: 

f- 10-11=- z -= w 

0:: 

W 

IlJ 

::E: 

~ 10-21=- -= 

10-31=- -= 

, ! I 10-41 , 365 o 

JAN FEB MAR RPR MAY JUN JUL RUG SEP OCT NOV DEC 

154 

';",~~F_---;P-,-;:::-"---".,.,,.,-=--;:--; -~';;""-:;;"Cj'";;;;'<;,,,",_~~""""""""F '~"""'%"_ 4 k ., _~="'~ - "", ,~~;;=>~""' ~'""~ ,,"""""'" •• """,""","*,, u ~, __ " f"r~""'" .4, >ZiJid,,,~,,"~~~~_~",,,,,,~#,$~ ""'"'~.,,~~"" 
Figure A.14.h CAMPBELL/I. PERCH EGGS 

102 ... , I I I I I f I I I I I iii I I I I Iii I j iii i I I i I I 1 I I I i I I f iii 1 f I , ..... 

1011=- --:: 

en 100b- L 

"-

0 

W 

Z 

IT 

g: 1O-1~ z 

w 

a: 

w 

ill 

L 

~ 1O-2~ 

10 -31=- --:: 

10-41 -

--.. ';:' :"' .'-:'~' : :-.. :::: .. -::::-~:::----:::--.. :---.... --.... --.... --.. ----.......... --~ o " !!!, - I! ',' 1 ' 1 ' , " ! ! ! 1 ! 1 !, ! ! I! I! !!!!, , I I I! 

365 

JRN FEB MRR APR MAi JUN JUL AUG SEP OCT NOV DEC 

en 

L 

'-o 

w 

z 

.-. 

IT 

a: 

~ 10- 1 

w 

a: 

w 

ill 

L 

~ 10-2 

FIgure A.1S.h PALISADES/i. PERCH EGGS 

! ! I 

10-41 1 365 o 

JRN FEB MAR APR MAi JUN JUL AUG 5EP OCT NOV DEC 

155 
Figure R.16.h BIG ROCK/i.PERCH EGGS 

1 02t: iii i I I i I I iii I I I Iii iii I iii iii i , iii iii i i .... 

to I,=- -

~ 100~ "- 0 

w 

z 

a: 

a:: 

J-- 1O-1~ z 

w 

a:: 

w 

co 

::E 

~ 10-2~ 

10-3~ -= 

10-41 o ! ! ! ! , :! I!! ! ! I! , ! ,! ! ! !, I!!!! 

365 

JRN FEB MRR RPR MRi JUN JUL RUG SEP OCT NOV DEC 

156 
I 

I 

I 

I 

10° 

10-

~ 10-2 

"-o 

w 

z 

a: 

w 

ro 

L 

~ 10-4 

10-5 

Figure R. 2. i D.C.COOK/i.PERCH LRRVRE 

10-6 

o 

I I I I 1" I I I I '" I 1 I. , I " I I I I I ,'I I I I I I I I I I I I I I I I I I I I I I I I I I I I I , I I I I I I 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

Figure R. 3. i BRILLYIY.PERCH LRRVRE 

100, iii iii iii iii iii iii iii iii iii iii iii ii,,,, 

10- 11::- -cJ 

~ 10-21=- -:;j 

"- 0 

w 

z 

~ 1O-3~ A w 

a: 

w 

ro 

L 

~ 10-41=- I I -

10-51::- -

10-6o , !! ! I! r!! ! t! I ! t I !! ! 1 I , ! t I! :!! h I! , !! If! ! ! !, !! !!! I !! ! !! t I I I 

365 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

157 
~ 10-2 

"-o 

w 

Z 

IT 

0::: !Z 10-3 

w 

0::: 

w 

en 

::E 

~ 10-lI 

10-61 , , , a ' , 

Figure R. 5. i PULLIRM/Y.PERCH LRRVRE 

! h !~ 'I: I I !! ! t ! 1 !! t! 

JRN FEB MRR RPR MRY JUN JUL RUG SEP OCT NOV DEC 

365 

Figure R. 8. i PORT WRSH/Y.PERCH LRRVRE 

100r::i I Iii Iii iii Iii I I Iii iii iii 1 iii I Iii i I Iii iii iii Iii i 13 

1O-1~ -::I 

~ 10-21=- - "-0 

w 

z 

~ 

IT 

g: 1O-3b- z . W 

0::: 

W 

en 

::E 

~ lO-lIb- .!lI T 

1O-5~ -::: 

I ", I I, I! I 10-6 , 365 

o 

JAN FEB MRR APR MRY JUN JUL RUG SEP OCT NOV DEC 

158 

" ~, ~ '~r_c'~< ,,, _ ~ -_~ ~".~.~.. ~+-..., __ =_"d<=Clq;"l",o;;;"_~,_¥. __ ;o ~ ~ 'v_ " __ ,...-::; __ a~=~ .... .., __ =~~" _~,_ ,iiMiI_uiJ!i! , Q ' "'e< i¥'''''''''"''''"'~Li£-'H 
Figure R. 14. i CRMPBELL/i.PERCH LARVRE 

100 ..... , I i I I I i I I I iii iii I ! I I iii' iii iii I i I I Iii t i i 1=1 

W-l -

--

'i: 10 -21=-

"-0 

w 

z 

CI 

~ 10-31=- -

w 

a:: 

w 

(I) 

L 

~ 10-41=- -

10-51=- -:: 

10-61 o !! !!! ! ! I !! f ! ! ,! ,! , f! ! ! : ! t t! !!, !! ! ! ! !! !! ! ! !! !!!! I ! It! !!!: !! 

365 

JRN FEB MRR APR MAi JUN JUL RUG SEP OCT NOV DEC 

Figure R.tS. i PRLISADES/I.PERCH LRRVRE 

100"'-1 , iii I I Iii i I I Iii iii I I I I i I Iii I f I I I I I i I I I'" 

10-11=- -:: 

'i: 10-21=- - "- 0 

w 

z 

CI 

g: 10-31=- -:: z 

w 

a:: 

w 

(I) 

L 

~ 10-41=- -

10-51::- -= 

10-6o • ! ! ! !, ! ! ! ! ! ! ! !! ! !, , ,! ! ! !, ! ! ! t! ! !!! , ! : ! ! ! :, ,! ,!,:!!, , ! ! ! ! ! !, f ! ! ! ! ! , I 

365 

JAN FEB MRR RPR MAi JUN JUL RUG SEP OCT NOV DEC 

15·9 
Figure R. 16. i BIG ROCK/i. PERCH LRRVRE 

10° ... iii I t iii iii iii i I I I I t ii' i , , Iii , I , I i I f i I ;::1 

10-11::- -:: 

1: 10-21::-

" 0 

w 

z 

cr: 

g: 10-31::- z -= W 

0: 

W 

o:J 

:E 

~ 10-41=- -

1O-5b- -= 

!! ! I! 10-61 • .• •. 365 

o 

JRN FEB MRR RPR MRi JUN JUL RUG SEP OCT NOV DEC 

160 

_ " <_, «-_ r_.~ __ "~ , __ .ap;;;;,~id\&'lf.,;h ,~, p",,~~ • _r"~ AA'i"~~ .,..<? '" • ~"'""'~~, ~'h~'''~ ".-,,~ ~_., c_ ~"" ,,~ """"' 
Table 81. Estimates of proportions of alewife standing stock impinged in 1975 and power plant impingement coefficients calculated using surplus ,production model. 

"OWE~ PLlNT I. ll. VOLUME FLOW BIOMA.SS HPINGED pp)r)QrIJN r,PINGEO I'IPTNGEltBNr COEFFICIENT 

1* 0.14B14'l01E+10 G.14693706E+06 0.734 7E- 03 o. 2 11:1 3 155 E- 1 2 

2 0.32729001E+10 O.11590391F.+:l5 0.5795E-04 O. 17706607£- 1 3 

3 0.66949990E+09 0.,)7543711E+04 O.l877B-OlJ 0.42975148E-1l 

4 0.59690010F.+OQ 0.200723<)1 E+:l'i O.1004E-Ol 0.16813B67E-12 

5 0.77470003E+09 0.41'1571291':+05 O.20bBE-0] 0.26692358E-12 

6 0.82170010E+09 0.56296 6AO 1':+04 O.2815E-Ol O. H256218E-l] 

1 0.1'iJ20000E+l0 0.38121164E+::l'l 0.1906E-Ol 0.12441632E-12 

R 0.lG942999E+l0 ().94791375E+05 0.4740E-Ol O. !l3311432E-12 

9 0.Q7340006f.+09 0.310/J5945E+:l/J 0.1552£-011 0.1777301f2E-13 

10 O. 24512000E+ 10 O.51005359E+05 O.2550E-03 O.10404161E-12 

11** 0.14324001E+10 0.37437020E+05 0.1872E-03 0.13061932!-12 

12 0.16513001E+10 0.36548961E+()5 0.1B27E-03 n.11066723E-12 

13 0.823fi9<)97E+0<) 0.62559492E+04 0.J1288-0!l 0.17974689E-13 

14 0.,)Il6Q0010E+Oq O.15387852E+04 0.76948-05 O.12S89809!-1l 

15 O. 11 Q400 OOF.+ 09 :l.127583!11E+02 0.6379E-07 0.53426818!-15 

16 0.95500000E+08 0.47816925E+:l1 0.23918-07 0.23035033E-15 

* Zion (plant 1) biomass impinged in 1975 was 0.9532 x 106. The value in the table is for 1974. 

** Waukegan (plant 11) biomass impinged in 1975 was 0.4536 x 105. The value in the table is for 1974. 

Table 82. Estimates of proportions of alewife eggs produced in 1975 that were entrained and power plant entrainment 

coefficients calculated using the surplus production model. 

POIlER PUNl' I. O. VJL1f'1E nOll NUMBER ENTPAINED PROPORTION ENl'RAINED ENT. COEFFICIENT 

1 0.3481400a+1G 0.14137398E+l0 0.38416852E-04 O.11034B88E-13 

2 0.3272Q001E+10 0.17nOOOOOE+10 O.4619'l666E-04 :l.14114605E-13 

3 O.66CJ!l9990E+09 0.4220187!1E+11) 0.11467905E-03 O.17129061E-12 

5 0.77470003E+09 0.43163904E+09 0.11729327E-04 0.15140473E-13 

6 0.82170010Et-09 O.47]49856E+08 0.12866813E-05 ,).15658710E-14 

7 0.1532000GR+10 0.4'i7fl5860E+01 0.124!11814E-06 ).31212884E-16 

8 0.109429<!C}E+10 0.37325210E+07 O.10142719E-06 0.92686885f.-16 

9 o. fl7340006E+09 0.5?Q72900E+07 O.l!1394Bl1R-06 0.16481355E-15 

10 0.24512000E+10 0.9268:l780E+07 0.25185000E-06 0.10274567E-15 

11 0.14324001E+10 0.16946424E+l0 0.1003H93E-OJ 0.70090689E-13 

12 0.16513001E+10 O.79521971E+09 0.21609230E-04 0.13086198E-13 

13 0.B2369Q97E+09 0.2<!844595E+10 0.Bl0H468E-04 O.98!157538E-13 

14 O.59690010R+0<) 0.140P.4319E+06 O.3B272603E-08 0.64118980E-17 

15 O.11940000E+09 0.0 0.0 0.:1 

16 0.955000001':+08 0.0 0.0 0.0 

rr1 

VI 

-f 

....... 

~ -f 

rr1 

VI 

0 

"'T1 

-c 

:;0 

0 

-c 

0 

:;0 

-f 

....... 

0 

:z » VI -0 ....... -0 

3: rTI 

-c Z ....... t::1 :z 

en 

rr1 -

>< 

0 

):::0 tP :z 

0 

rr1 

:z 

-f 

:;0 

):::0 

....... 

:z 

rr1 

0 

0 

c:: 

:;0 

...... 

:z 

en 

--' 

1.0 

'-I 

(J'1 
Table B3. Estimates or proportions of alewife larvae produced in 1975 that were entrained and power plant entrainment 

coefficients calculated using the surplus production model. 

PJWER PLANT T.D. VOLUME FLOIl NnMBER ENTRAINED PROPORTInN ENTRAINED ENf. COEFFICIENT 

1 0.34814001£.10 0.15972468E.08 0.43403503E-04 0.12467245E-15 

2 0.327290011':.10 0.21000000E"09 0.57055301E-03 0.17435688E-14 

3 0.669119990£+09 0.4Hi15264E+08 0.11308512E-03 0.16890966£-111 

5 0.77410003E+09 0.66691250£+05 0.181226118£-06 0.23393090£-11 

6 0.82170010E+09 0.62247200E+06 0.16915019£-05 0.20585316£-16 

7 0.15320000E+10 0.34300350£+06 0.93207609£-06 0.&0840408£-11 

8 0.10942999£+10 0.42359631£+06 0.11510183£-05 0.10518849£-16 

9 0.81340006£+09 0.10956510£+07 0.2917 3164 £-05 D.34088175£-16 

10 0.245120001':+10 0.24118260£+07 0.673]2321E-05 0.27469106£-16 

11 0.14324001E+10 0.51204880£+011 0.139114390£-0] 0.97140219£-15 

12 0.1651]001E+10 0.41444900E+07 0.11262217E-04 0.68202041E-16 

13 O.82369991E+09 0.10098325E+08 0.274111129E-D4 0.33314441£-15 

14 0.59590010E+09 0.61564883£+04 0.16729611E-01 0.28021464E-18 

15 0.11940000E+09 0.73B1733E+01 0.19872770£-1() O.16&43853E-20 

16 0.95500000E+08 0.10062328£+02 0.27341322E-10 0.28631124£-20 

Table B4. Estimates of proportions of yellow perch standing stock impinged in 1975 and power plant impingement coefficients calculated using the 

surplus production model. 

~ POWER PLANT I. C. ~(jLUME FLew 810MASS IMPINGED PRCPC~TIC~ I~PINGED IMPINGEMENT COEffICIENT 

1 * C.348140CIE+lC 0.25907446E+03 2 0.2591E-C4 C.HH6123E-14 

3 O.66949990E+09 

0.327290CIE+IC 0.96<;31714£ +03 0.9693E-04 O. 296161t60 £-13 

4 O.54530869E+02 0.5453E-05 0.81450180E-14 

5 

C.5C;69CCICE+CC; 0.82189819E+02 0.8219E-05 0.13169446£-13 

6 

C.77470C03Et09 0.4<;1E6758E+C4 0.4979E-03 0.64265851£-12 

7 O.15320000E+IC 

C.8217001CE+09 0.44378845E+02 0.4~38E-05 0.54008.583£-14 

8 O.lO<;42999E.IO 

0.431t8C45E+C2 0.4317E-05 0.28171518E-14 

9 0.4C887146E+02 C.4C89E-C5 0.31363141E-14 

10 O.24512CCCEtlC 

0.87340CC6E+C9 O.631C9789E+Ol 0.6311E-06 0.72257628E-15 

11 ** O.l4324001E+IO 

O.15.,75256E+C3 0.1528£-04 0.62317468E-14 

12 

0.55464066H02 C.5546£-C5 c. 38721061E~14 

13 O.82369997E+0<; 

C.lt!:13CCIE+lC O.10772821E+03 0.1011E-04 0.65238444£-14 

14 0.59'i53842E+02 C.5995E-C5 O.72186049f-l+ 

15 

C.5<;69CCICE+C<; 0.1lC;22538E+02 0.1192E-05 O. 19974096£-14 

16 

0.1l9400COE+C'i O.llE47347E+OC 0.1185E-07 0.99224020E-16 C.955000COE.08 O.242C7201EtOI C.2421E-C6 C.25347855£-14 

* Zion (plant 1) biomass impinged in 1975 was 0.1420 x 103. The value in the table is for 1974. 

** Waukegan (plant 11) biomass impinged in 1975 was 0.6145 x 102• The value in the table is for 1974. 
...... 

~ 

w 

Table 85 Estimates of proportions of yellow perch eggs produced in 1975 that were entrained and power plant entrainment coefficients calculated using the surplus production model. 

PCkEFI PLANT I. C. VOLU'IE HC .. ~u .. eEP H TI<AI~ED FFOPORTIO~ ENTRAlhED EhT. C(EffICIEhT 

1 O.3481400lE+I0 C .C C.O C.C 

2 0.3272%0IE+I0 o .18800000E+08 0.57566285E-C4 C.1758E175E-13 

3 C.t694C;C;C;CE+C9 C. 13 5 e083tE+05 0.41585022E-07 0.62113561E-16 It 0.774100')3E+09 0.452~4220E+C7 o .138HC12E-C4 0.11890888E-13 

6 C.8211CCICE+C9 O.C 0.0 0.0 

7 0.1532000(E+I0 C.C c.e o.c 

8 0.1O'I4299SE+lO 0.0 0.0 o.c 

9 0.8734COO(;E+C" C.O 0.0 0.0 

10 O. 2451200Cf: HO 0.0 0.0 0.0 

11 O.14324l,;CIE+I0 0.0 0.0 0.0 

12 ll.165130CH-+l0 c.e O.C 0.0 

13 0.82369997E+09 0.0 0.0 o. C 

14 C.5"69CCICE+C9 c.o 0.0 0.0 

15 o .11940000E +C9 c.o 0.0 0.0 

16 C.9550COCCE+C8 0.0 0.0 c.o 

Table 86. Estimates of proportion of yellow perch larvae produced in 1975 that were entrained and power plant entrainment coefficients calculated using surplus production model. 

POkER PLANT I. C. VOLUME flO" M."SEFi EI\TI<~INED FRCPCRTION ENTRAINEC ENT. COEFFICIENT 

2 

1 C.34814CCIE+IC C.C 0.0 0.0 

3 

0.32729001E+I0 C.15~(OCC(E+C6 0.46849207E-C4 0.H314269E-15 

5 e.669't"99(E+09 0.15528816E+05 0.47549856E-C5 C.11022e79E-16 

Ii 0.17470CC~E+C9 C.<;lC21SS4E+C6 0.21871295 E-03 o .35916844E-14 0.82110010E+09 0.0 0.0 0.0 7 0.15320CC(E+IC 0.0 0.0 0.0 8 0.1094299<;E+I0 C.t124SC;S4E+C4 0.20591906E-05 0.18817406E-16 

10 

9 O. a 734000tH09 0.0 0.0 o.c 0.24512CCCE+IC C.C 0.0 0.0 

12 

11 o .14324CO lEi 10 0.0 0.0 0.0 0.165130CIE+I0 0.0 0.0 0.0 H 0.823699'17E+C9 C.C 0.0 0.0 

15 

0.5969001CE+C9 0.0 C.C c.o 

16 0.1l94CCCCE+CC; c.e 0.0 0.0 0.9550CC((E+08 C.O 0.0 0. 0 
1 do t k 0 0 d lOn 1975 and power plant impingement coefficients calculated using the surplus Table B7. Estimates of proportions of sme t stan lng s oc lmplnge 

production model. 

POWER Pl ANT I. c. VOLU~E FLOW BIO~ASS IMPINGED PROPORTI[~ IMPINGtD I~PINGEMENT COEFF Ie lENT 

1 * O. 348140C IF+lO 0.21409414 E*05 o .1096E-02 C.31492425E-12 

2 J.3:029001f*10 O.1l814174E+03 0.4726E-05 o .14439517E-14 

3 0.66949990E*09 O.29758041E*02 C.1190E-05 C.11119266E-14 

4 0.5e;69COIOH09 0.20418350E+02 0.8167 E-Ot> C.13682928E-14 

5 0.77470003E-t09 0.874338 3BE +03 0.3497E-04 0.45144620E-13 

6 0.82170010E+09 0.69506B6JE*03 o .2760F-04 C.33835632E-13 

7 J.15320000E+IC O. 136076 59E +04 0.5443E-04 0.35529136E-13 

8 0.10942999f*10 0.15913701E+04 0.6365f-C4 C.56169398E-13 

9 O.873400C6E+09 0.75266027E+Ol o .301lE-06 0.34470345E-15 

10 0.24512000EHC O.55522613E+04 0.2221 E-03 0.90605095E-13 

11 ** 0.143l4001E*lO 0.21116650E+Ol o .lC65E-04 C.7572361:1E-14 

12 o .H513001E*10 0.60C69641E*02 0.2403E-05 O.14550872E-14 

13 O.82369997E+09 0.54151020E+01 0.2166E-06 C. 262 96411 E-15 

14 0.5969CCICE*0e; 0.1605558>JE+02 o .6422E-06 C.10759315E-14 

15 o .1l940000E +oe; 0.23694100E+OO 0.9478E-08 0.79319229f-16 

16 O.95500000E*08 0.29622702E+Ol C.1l93E-06 O.12491164F-14 

* Zion (plant 1) biomass impinged in 1974 was 0.4263 x 104. The vaiues in th7 table are for 1974. 

** Waukegan (plant 11) biomass impinged in 1975 was 0.5448 x 103. The values ln the table are for 1974. 

Table B8. Estimates of proportions of smelt eggs produced in 1975 that were entrained and power plant entrainment 

coefficients calculated using the surplus production model. 

POWER PLANT 1.0. VOLUME flOW NUMBER ENTRAINED fROPORTION ENTRAINED ENT. CO E FF I C lENT 

1 O.34614001EHO 0.7435e;C;36E*C9 O.,)5421679E-03 O.15919366E-12 

2 0.32729001E*10 0.7,)200000H06 0.56047807E-04 0.17124814E-13 

3 O. 66949990E+ 09 O.45243650E+07 O.33720R35E-05 0.50367222E-14 

5 O.77470003E+09 0.76767190E+07 O.51215857E-C5 O.73855419E-14 

6 O.82170010E+C9 O.49827080E+07 0.37136942 E-05 O.45195239E-14 

7 0.15320COOE+10 0.0 0.0 0.0 

8 0.10942999H 10 O.24!:84688E+06 0.18323374f-C6 C. H:744383E-15 

9 o. 8134000~E+09 C.C 0.0 0.0 

10 0.24512000E+10 0.10(CR<;56E+06 0.14598404E-07 0.30433417E-16 

11 0.14324001E+I0 0.23360851H09 o .17411230E-C3 0.12155283E-12 

12 0.16513001E+I0 0.31467616E+OB 0.23453322 E-04 0.14202950E-13 

13 0.82369997E'+09 0.21424140E+07 0.15967162[-C5 0.1<;3B5416E-14 14 0.5969001 CE+ C9 0.0 0.0 0.0 

15 o .11940000E +09 C.O C.O 0.0 

16 0.95500000E+08 0.0 0.0 O. C 
----- ---

...... 

m 

01 

---------- ---- ------

Table 89. Estimates of proportions of smelt larvae produced in 1975 that were entrained and power plant entrainment 

coefficients calculated using the surplus production model. 

POwER PLANT 1.0. VOLUME HOIo t\U"SER ENTRAINED PPOPORTIO~ ENTRAINED fNT. CCEFFICIEt><T 

1 0.34814001E+I0 0.11920482 H08 O.88345403E-03 O.~5519<;99E-14 

2 0.3272900 1E+ 10 0.244COCOOE+01 0.18185742 E-03 0.55564551E-15 

3 O.66949990E+09 0.31314588[+06 0.23384011E-C4 O.34<;27573E-15 

5 0.71410003E+C9 0.13520C88E+06 0.1 OJ1£, 756 E-04 0.13001287F-15 

6 0.82170010£+09 0.10 l!'92C5E+08 0.75941905E-03 0.<;2420315E-14 

7 0.1532COOCHI0 0.19427820E+07 0.14479a9lE-03 0.<;451615CE-15 

8 0.10942999E+I0 C.43C49138E+06 0.32085256E-04 0.2932032lE-15 

9 0.87340006E+09 0.0 0.0 O.C 

10 0.2451200CE+10 0.66561890E+01 0.49614185E-03 0.(0240761E-14 

11 0.14324001E+10 0.18212669E+06 0.l3618936£- C4 0.95077648E-16 

12 0.16513001 E+ 1 0 0.10883388 E+06 0.al115768E-05 0.49122313£-16 

13 0.82369997E+09 0.98<;5877CE+01 0.73155612£-03 0.1l9541818E-1'. 

14 0.59690010E+09 0.24795961E+C3 0.18480861E-07 0.3C961310E-18 

15 0.11940000E+09 0.14613811£+02 0.10891925£-08 0.'H222041E-19 

16 0.95500000E+08 0.52509033E+03 0.39135891E-C1 0.40919950E-17 

Table BID. Estimates of proportions of alewife standing stock impinged in 1975 and power plant impingement coefficients calculated using the 

dynamic pool model. 

"JWEF PLANT I. D. VOLUME FLOW BIOMASS I!!i>INGED PR)POprrON IMPINGED I"PINGEftEHr COBFFI=IEIT 

1* O.H814001E+l0 0.14693106E+06 0.6189E-OJ 0.17778427E-12 2 0.32729001E+10 0.11590391E+05 0.1I882E-OII 0.14916992E-13 ] 0.66949'190E+09 0.57543711E+04 0.2424E-04 0.352011570£-13 4 0.59690010E+0'l 0.20072391F+0'5 O. 84558-0" 0.141648951':-12 5 0.77470003E+09 0.41357129E+0<; 0.1742E-OJ 0.22487063E-12 6 O. R21100 1 OE+09 0.56296680E+OII 0.23718-04 0.2£18592138-13 1 0.1<;320000E+10 0.38121161IE+05 0.1606E-0] 0.10481497E-12 13 0.10942999E+10 0.94791315E+05 0.3993E-0] O. ]&fJ'l1865E-12 9 0.81340006E+09 0.31045945E+04 0.1308E-04 O.14972961E-13 10 O. 24512000E+ 10 0.51005359E+0,) 0.2148E-03 0.87650210£-13 11** 0.14324001E+10 0.37437020E+05 0.1577E-03 O.11009124E-12 12 O.16513001E+10 0.36548961 E+05 O.1540E-03 0.932]2008E-13 13 0.82369997E+09 0.62559492E+04 0.2635E-04 O. J1991906E-13 14 0.59690010E+09 o .153R7852E+04 0.6482E-05 0.10859364E-1] 15 0.11940000!+OQ 0.12758341E+02 0.53748-07 0.450096588-15 16 0.9<;500000E+OR O.47816925E+Ol 0.2014E-07 O.21090856E-15 

* Zion (plant 1) biomass impinged in 1975 was 0.9532 x 10°. The value in the table is for 1974. 

** Waukegan (plant 11) biomass impinged in 1975 was 0.4536 x 105• The value in the table is for 1974. 
.~ 

..... 

0'\ 

0'\ 

Table B1l. Estimates of proportions of alewife eggs produced in 1975 that were entrained and power plant entrainment coefficients calculated using the dynamic pool model. 

1>Oil EI! PLANT I. D. VOLU~E FLOil NUMBER ENTRAINED PROPORTIO'l ESfRATNED EN!. C::>EFPICIE!4T 

1 0.34814001E+10 0.14137398Et-10 0.84987143E-Ol O.24411771E-12 

2 0.32729001E+l0 0.170QQQOOF.t-11} 0.10219573Y.-02 0.3122483"£-12 

3 0.6694 999GE+ 09 0.4?20187L1Et-10 0.25369711E-02 O.37893525E-11 

;; 0.7747000.1F.+09 O.41163904E+09 0.259~8021E-OJ /).33494301E-12 

6 0.821700101':+09 0.471498 56B+ 0'1 O.2846"419E-Ol 1.H640900E-13 

7 O.1532000llE+10 O.45785860Et-07 O.275242?9E-05 0.17966208£-14 

8 0.109429991':+10 O. ]732521 OEt- 07 O.2243'109aE-O'l 0.20504525E-14 

9 0.87340006P.+09 0.52972900£+07 0.31844 n9R-05 0.36460635£-14 

10 O.24512000E+1::J 0.92680780E+07 0.55715172E-05 ').22729754£-14 

11 0.1l1324001E+10 0.36946424 Et-10 0.22211)391E-02 0.15505713£-11 

12 0.165130011':+10 0.795?1971R+09 0.~780H18E-03 0.2894CJ759£-12 

13 0.82369997F.+09 0.29844595Et-10 O.17941117E-02 O.21781121E-11 

14 O.59690010E+09 0.140'l4319Et-06 0.'I46SQ045E-07 O.14184631E-15 

15 O.11940000E+09 0.0 0.0 0.0 

16 0.95500000E+Ofl 0.0 0.0 0.0 

Table 812. Estimates of proportions of alewife larvae produced in 1975 that were entrained and power plant entrainment coefficients calculated using the dynamic pool model. 

?aWEI! PLANT I. D. VOL!n!E FLOW NUMBRR ENTFAINEJ} PROPORTI3N ENfRAINEO EIIT. COEPFICIEIT 

1 0.34814001E+10 0.1')972468B+08 0.96018799E-03 0.27580492E-14 

2 O.32729001E+10 0.210000001':t-09 0.12624189E-01 0.38511858E-13 

3 0.66<)4 9990E+ 09 0.41615264E+08 0.25017 096E-02 0.37366804£-13 

5 0.7747000nt-09 0.66691250E+05 0.40091572E-05 0.51751040E-16 

6 0.82110010E+09 0.62247200Et-06 0.37420011E-04 0.45539110E-15 

7 0.153200001':+10 0.14]OO350E+06 0.20619715E-04 O.13459335E-15 

8 0.109429991':+10 0.42359631E+06 0.25464571E-04 O.23210155E-15 

9 0.813400061':+09 0.109'56510E+07 0.658652721>.-04 0.15412402E-t5 

10 0.24512000U10 O.24778260E+07 O.1489,)499E-ln 0.60168134E-15 

11 0.14324001E+10 O.51204S80E+08 0.307f11913E-02 O.21489724E-13 

12 O.16513001Et-10 0.41444900E+07 0.249146721-03 0.t5081904E-14 

13 0.B2369991Et-09 0.10098325E+OB 0.60706260E-Ol 0.73699422E-14 

14 0.5969001IJE+09 0.615fi4883Et-04 0.370H846E-06 0.62003366E-17 

15 0.119400001':+09 0.731l1133Et-01 O.43963217E-09 0.36820132E-19 

16 0.9')5000001':+08 0.1006232JC1E+02 0.604'1988IJE-09 O.63340115E-19 
Table 813. Estimates of proportions of yellow perch standing stock impinged in 1975 and power plant impingement ,coefficients calculated using the 

d.vnamic pool model. 

PCwER PLA"'T I. e • \/CLUME FLew BIOMASS IMPINGED PRCFORTICII. I'PIII.GED IMPINGEMENT COEffICIENT 

1* C.348l40ClEflC 0.25«i01446Et03 0.2578E-C4 (.7lt057243E-14 

2 o .321290C lEtlC O.<)t<;:H 7l4E+03 0.«;646E-Olt 0.29473392E-13 

3 0.{:6<)4<)<)90E+09 0.54530869E+02 C.5427E-C5 0.81056116E-14 5 O.7147CCC3EtC<; 0.821898l9E+02 0.8179E-05 0.10557998E-13 

6 0.82170ClCEtO<; o. 4<;ift 758E+04 0.4955E-03 0.60297259E-12 

7 0.15320000E+lC 0.44378845E+02 o .Itlt 16E-05 0.28821987E-14 

8 C .IC942999E*lC 0.43H:8C45E+C2 0.4296E-05 o .39257504E-14 

g 0.8134000E:EtO<; 0.40a87146E+02 0.4"9E-Q5 0.46587591E-14 

10 0.24512ceCE+1( 0.E:310<)189E+Ol 0.~280E-C6 O.25622111E-U 

11** o .14324001E + lC 0.15~15256E+03 0.1520E-04 0.10612581tE-13 

12 C.1651300lEt 10 0.55464066E+02 0.5520E-05 0.33425810E-14 

13 C.€236<;<;<;7EtC<; 0.IC112821E+03 0.1072£-04 0.13015403E-13 

14 0.59690010E+0<) 0.5<;<;53842E+02 0.5<)66E-05 o. 99956800 E-14 

15 0.1lc;4cceCE+e<; 0.11 <;225 38£+02 0.1I86E-05 C.99371398E-14 

16 0.95500ceOEtC€ C.llE41347E+CC 0.1179E-07 0.12345613£- U 

* Zion (plant 1) biomass impinged in 1975 was 0.1420 x 103

• The value in the table is for 1974. 

** Waukegan (plant 11) biomass impinged in 1975 was 0.6145 x 102. The value in the table is for 1974. 

Table 814. Estimates of proportions of yellow perch eggs produced in 1975 that were entrained and power plant entrainment coefficients calculated using the dynamic pool model. 

PChEl< Fl;ANT I. C • VOLUME FLO. "'U~eER ENTRAINED P~CPORT'ON e~lRAINeO EII.T. CCEfflCIEH 

1 0.34814()Olt:tl0 0.0 0.0 0.0 

2 ('.3272<;CCIE+I0 O.IS800000E+08 0.24184586 E-03 O. H893lt20E-13 

3 O.6694'l<;<;CE+09 C.13 ~ ec f36E+C5 0.11470575E-06 0.U094968E-15 

5 0.7147 C003E+09 0.4526422CE+07 0.58228528E-C4 0.1!!162t1tlE-13 

6 0.8211CCICE+CC; C.O 0.0 0.0 

7 G.lS32COJct+lO c.e 0.0 0.0 

8 C.IC942<;<;<;1:+10 0.0 0.0 c.e 

9 O.8734CcOtl:+es e.e 0.0 0.0 

10 0.2451200CE-+IO 0.0 C.O C.C 

11 0.14324CulE+10 0.0 0.0 0.0 

12 O.1b5130CIE+IO e.e c.o 0.0 

13 0.tl2369997E+09 O.C 0.0 O.C 

14 C.5969CCHE+Cr; C .0 0.0 0. 0 

15 O.1l'J4QOOCl:tC9 C .0 O. a 0.0 

16 O.95500CCCE+C8 C .0 0.0 0.0 
....... 

0"1 

co 

Table B15. Estimates of proportions of yellow perch larvae produced in 1975 that were entrained and power plant 

entrainment coefficients calculated using the dynamic pool model. 

POIIER PLANT 1.0. ~ulIJME FLO ~Uf<eE F Ell Tf'lJNEC F~OPCRTION E~TRAINED ENT. (OEFf Ie lENT 

1 0.348140C1E+1C c.e O.C 0.0 

2 0.3272'1v\)IE+1O 0.15300COCE+C6 C.19682158E-C3 0.HI3661lE-15 

3 L.6694"""CHC9 0.15528616E+05 0.19976505E-04 0.2Cj837921E-15 5 0.7747CC03E+09 e.91C21C;<;4E+C6 C.1l109211E-02 0.15114493E-13 6 0.8217001CE+C'l 0.0 0.0 o.c 7 0.1532COOCE+IC c.c 0.0 0.0 8 0.1094299<;E+IO 0.67248<;64E+C4 0.8651C145E-C5 0.1'iC5511t7E-16 9 0.87340COtE+C9 0.0 0.0 0.0 

10 O.245120CCHIO c.e C.C O.C 11 0.1432400 lE: + 10 0.0 0.0 C. C 12 0.lt5130C1E+IC c.e 0.0 o.c 13 0.82369997£'+C9 c.c C.C O.C 14 0.596900lCE+CC; 0.0 0.0 c.c 15 0.1194ccceE+C'l C.C 0.0 0.0 

16 0.955uOOOCE+08 0.,0 o.a O. ° 

Table B16. Estimates of proportions of smelt standing stock impinged in 1975 and power plant impingement coefficients calculated using the dynamic 

pool model. 

POWER PLANT I. c. VClUME FLOW BIOMASS IMPINGED PROPORTIC~ IMPINGE~ IMPINGEMENT COFFFICIENT 

1* 0.34814CCIE'+IC 0.214C9414E+05 0.1110f-02 0.31877669[-12 

2 o .3212900lE+I0 0.11814714E+03 0.4784[-05 0.14616114f-14 

3 0.669499<WE+CC; 0.29758041E+02 o .1205E-05 C.1799676"E-14 

4 o .5969COI OE+O'1 0.2041B350E+02 O.8261E-06 O.13850321E-14 

5 0.77470003F+09 0.87433838E+03 0.3540E-04 C.45696902E-13 

6 0.62170010E+09 0.69506860E+03 o .2814E-04 C.34249571E-13 

1 0.15320000E+I0 0.13607659E+04 0.5510E-04 0.35963786E-13 

8 0.10942999E+I0 0.15913701E+04 o .6443E-04 C.58881014E-13 

9 0.81340006E+09 0.752t,6027E+Ol 0.3041E-06 0.34892040E-15 

10 0.24512000E+lO 0.55522813E+04 O. 2248E- 03 C.91713529E-13 

11** 0.143240CIE+IO 0.27116650H03 0.1098E-04 o. 76650044E- 14 

12 0.16513001E+I0 0.600to9641E+02 0.2432E-05 0.14728882E-14 

13 O. 82369997f +09 0.54151020E+Ol o .2193f-06 0.26618180E-15 

14 o .5CJ690010E+0C; O. 16G55588f+02 0.650lE-Oll C.I0890940E-14 

15 o .11940000E +09 0.236<;4700E+00 C.9594E-08 C.80350326£:-16 

16 O. 95500COOF + 08 0.29822102 E+Ol 0.1208E-06 0.12643995E-14 

* Zion (plant 1) biomass impinged in 1975 was 0.4263 x 104. The value in the table is for 1974. 

** Waukegan (plant 11) biomass impinged in 1975 was 0.5448 x 103. The value in the table is for 1974. 
,--------- -- -------- --------~-- "-------- ------- ---- ---- -

Table B17. Estimates of proportions of smelt eggs produced in 1975 that were entrained and power plant entrainment 

coefficients calculated usin9 the dynamic pool model. 

PCWER PLANT 1.0. VOLUME FLOw NU.,BER ENTRAINED PROPCRTIC~ ENTRAINEC ENT. CCEFF IC lENT 

1 0.34814001E+10 0.74359<;36E+09 0.16500093E-01 0.47394996 E-ll 

~ 0.32729001E+10 0.75200000 E+08 0.16686500E-02 0.5C'163832E-12 

0.66949<;'10E+09 0.45243650E+07 0.10039H7E-03 0.14995280E-12 

5 0.17470003E+09 0.76767190E+07 0.17034251E-C3 0.21988195E-12 

6 O.82170010E+09 0.49821080E+07 0.l1056316E-03 0.1:3455491E-12 

7 o .1532000CE +10 0.0 0.0 0.0 

8 0.10942999E+I0 0.24584688E+06 O. 54552174E- 05 0.49851209E-14 

9 0.81340a06E+09 0.0 0.0 0.0 

10 0.2451Z000E+10 0.10008956E+06 0.Z220<B60E-C5 0.9C606098E-15 

11 0.14324001E+l0 o .233(:085lE+09 0.51836520E-C2 0.3(;188596E-11 

12 0.16513001E+10 0.31467616E+08 0.69825049E-03 0.42284893E-12 

13 0.82369997E+09 0.2142414()E+07 0.47539070E-04 0.57714033£-13 

14 O.5969001CE+09 0.0 0.0 0.0 

15 o • 119400COE+C9 0.0 0.0 0.0 

16 o .95500000E +08 0.0 0.0 0.0 

Table B18. Estimates of proportions of smelt larvae produced in 1975 that were entrained and power plant entrainment coefficients calculated using the dynamic pool model. 

POWER PLANT I. D. VOLU~E FlC'" ~UMeER ENTRAI~EO PROPORTION ENTRAINED ENT. COEFfIC lENT 

1 0.34814001E+10 0.11920482 E+08 0.26450977 F.-O 1 0.75917852E-13 

2 0.32729001E+10 0.24t,COCOCE+07 0.54142401E-02 0.16')'.2f.25E-13 

:; 0.66949990E+09 0.31374588E+06 0.69618691E-03 0.lC39et03F-13 

5 O.71470003E+09 0.13':2::1C88E+06 0.10000415 E-03 0.3872516lE-14 

6 0.82170')10E+09 0.10189205E+08 0.22(:0'1357E-01 0.27515316E-12 

7 0.1532000CE+I0 0.19427820E+07 0.43109395 E-02 0.28139261E-13 

8 0.10942999E+10 O.43C4913flE+06 0.95523964E-03 0.81292200[-14 

9 0.87340006£+09 0.0 0.0 O. C 

10 0.245120COE+10 0.66567890[+07 0.14711093f-Ol 0.60260553[-13 

11 0.14324001[+10 0.18212669E+06 0.40546176E-03 0.28306429f-14 

12 0.16513001E+10 0.10€S3388E+06 o .24149715E-03 0.1462465lE-14 

13 0.823b9997[+C9 0.98<;58710E+C1 0.21'158474E-Ol 0.26658309F-12 

14 0.59690010[+C9 0.24795967E+03 0.55021059[-C6 0.921719t,7f-17 

15 0.1l94000CE+C9 0.11,(: 13 EllE +02 0.32427344E-07 0.2715854I1E-17 

16 0.95500000E+08 0.52';09033E+03 o .11651500F- 05 0.1~20C512E-15 
Distribution for ANL/ES-109 (EPA-905/3-81-001) 

Internal: 

W. E. Massey W. K. Sinclair 

R. E. Rowl and 

W. J. Hallett 

E. J. Croke 

M. M. Thommes (10) 

S. A. Spigarelli (10) 

A. L. Jensen 

ANL Patent Dept. ANL Contract File 

ANL Libraries (2) 

TIS Files (6) 

External: 

U. S. EPA, Region V (123) 

DOE-TIC (27) 

Manager, Chicago Operations Office, DOE 

President, Argonne Universities Association 

Radiological and Environmental Research Division Review Committee: 

A. K. Blackadar, Pennsylvania State University A. W. Castleman, Jr., University of Colorado 

H. L. Friedel 1 , Case Western Reserve University Hospitals R. E. Gordon, University of Notre Dame 

R. A. Hites, Indiana University 

D. Kleppner, Massachusetts Institute of Technology G. M. Matanoski, Johns Hopkins University D. W. Schindler, University of Manitoba 

W. H. Smith, Yale University 

170 
TECHNICAL REPORT DATA 

(Please read Instructions on the reverse before completing) 

1. REPORT NO. 

1

2

. 

3. RECIPIENT'S ACCESSION NO. 

EPA-905j3-81-001 

4. TITLE AND SUBTITLE 5. REPORT DATE 

An Assessment of the Impacts of Water Intakes on April 1981 

Alewife, Rainbow Smelt, and Yellow Perch Populations 6. PERFORMING ORGANIZATION CODE 

in Lake Michigan 7. AUTHORIS) 8. PERFORMING ORGANIZATION REPORT NO. 

S. A. Spigarelli, A. L. Jensen, and M. M. Thommes ANLjES-109 

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT NO. 

Ecological Sciences Section 

Radiological and Environmental Research Division 11. CONTRACT/GRANT NO. 

Argonne National Laboratory Araonne Illinois 60439 IAG#EPA-79-D-F0819 

12. SPONSORING AGENCY NAME AND ADDRESS 13f: TYPE OF REPORT AND PERIOD COVERED 

U.S. Environmental Protection Agency inal 

230 South Dearborn 14. SPONSORING AGENCY CODE 

Chi cago, Illinois 60604 

15. SUPPLEMENTARY NOTES 

16. ABSTRACT 

A large volume of water is withdrawn from Lake Michigan for cooling and other 

industrial and municipal purposes. Potential ecological impacts of such withdrawals 

have caused concern. This study estimates the impacts of entrainment and impingement at water intakes on alewife, smelt, and yellow perch populations of Lake 

Michigan. Impingement and entrainment estimates were based on data collected by 

utilities for 316(b) demonstrations at 16 power plants. Two conventional fishery 

stock assessment models, the surplus production model and the dynamic pool model, 

were applied to assess the impacts. Fisheries data were applied to estimate the 

model parameters. Movements related to spawning and seasonal habitat selection 

cause high variation in impingement and entrainment over time and location. Impingement and entrainment rates were related to geographic location, intake type and 

position, and volume of water flow. Although the biomass impinged and numbers 

entrained are large, the proportions of the standing stocks impinged and the 

proportions of the eggs and larvae entrained are small. The reductions in biomass 

assumi ng full flow at all intakes and our estimates of biomass in 1975 are predicted 

by the models to be: 2.86% for alewife, 0.76% for smelt, and 0.28% for yellow perch. 

- 17. KEY WORDS AND DOCUMENT ANALYSIS 

a. DESCRIPTORS b.IDENTIFIERS/OPEN ENDED TERMS c. COSATI Field/Group 

Cooling systems Fishery models 

Water 138 intakes Stock assessment 

Impingement Alewife 

Entrainment Rai nbow smelt 

Lake Michigan Yellow perch 

18. DISTRIBUTION STATEMENT 19. SECURITY CLASS (This Report) 21. NO. OF PAGES 

Release unlimited 170 20 SECURITY CLASS (This page) 22. PRICE 

EPA Form 2220-1 (Rev. 4-77) PREVIOUS EOITION IS OBSOLETE 

171 
United States 

Environmental Protection 

Agency 

Official Business 

Penalty For Private Use 

$300 

Great Lakes National 

Program Office 

536 South Clark Street 

Chicago, Illinois 60605 

Postage 

Paid 

Environmental 

Protection 

Agency 

335 

~~ 

-

U.S.MAll -® 

Design: USEPA ~egion V, Graphic Arts Section 1981