5~So FP - ?B~;, r;.cful-f-14

. 

EDWARD 

P. TAFT

PRELIMINARY INVESTIGATIONS

, INTO THE USE OF A CONTIN'UOUSLY OPERATING

FINE MESH TRAVELING SCREEN

TO REDUCE ICI-ITHYOPLANKTON EN1RAIN~1ENT

AT INDIAN POINT GENERATING STATION

DECEMBER 1977

Consolidated Edison Company of Nett) YOrk) Inc.

IRVING PLACE

NEW YORK, NE\V YORK 10003

ECOLOG!CAL

ANALYSTS

INC.
PRELIMINARY INVESTIGATIONS

INTO THE USE OF A CONTINUOUSLY OPERATING

FINE MESH TRAVELING SCREEN

TO REDUCE ICHTHYOPLANKTON ENTRAINMENT

AT INDIAN POINT GENERATING STATION

Prepared for:

Consolidated Edison Company of New York , Inc.

4 Irving Place

New York , New York 10003

Prepared by:

Ecological Analys ts, Inc.

D. 2 Goshen Turnpike

Middletown, New York 10940

December 1977
TABLE OF CONTENTS

INTRODUCTION

SUMMARY

SITE DESCRIPTION

4. METHODS AND MATERIALS 4-1

4 . 1 FINE MESH SCREEN

4 . COLLECTION DEVICE

COLLECTION EFFICIENCY

IMPINGEMENT SURVIVAL

DATA ANALYSIS

4-1

4-1

4-3

4-3

COLLECTION EFFICIENCY

SURVIVAL ESTIMATES

5 . RESUL TS

Proportion Surviving

Impingement and Collection

Estimates of Impingement

Survi val

5-5

6. DISCUSSION

APPENDIX A: RAW DATA
LIST OF FIGURES

llI1E

Cross-sectional view of Indian Point Generating

Station Unit 1 showing location of fine mesh

tra veling screen.

Collection device used for fine mesh traveling

screen studies at Indian Point.

4-2

Latent survival of striped bass larvae collected

at the fine mesh traveling screen at Indian Point,

June 1977.

Latent suryi val of striped bass juveniles collected

at the fine mesh traveling screen at Indian Point,

June 1977.

5-7

Length-frequency of striped bass larvae impinged

on a fine mesh traveling screen compared to those

collected by pumps.

111
LIST OF TABLES

Results of fine mesh traveling screen collection efficiency for release on 7 June and 14 June 

1977.

Total numbers and mean lengths of each taxon and life

stage collected for survival determinations at the

fine mesh traveling screen, June 1977.

5-3 Initial and 96-hour survival of each taxon and life

stage collected at the fine mesh traveling screen

at Indian point, June 1977.

Numbers of fish larvae and juveniles surviving to 96

hours after impingement on a continuously operating

fine mesh traveling screen including effects associated with sample collection and handling.

Numbers of control larvae and juveniles surviving to

96 hours after experiencing only sample collection

and handling effects.

5-3

A-3
25"""""

Co) ?;(PO Yr.

..? 

/ h'\

INTRODUCTION

The objectives of the studies described in this report were to determine

the survival of striped bass Morone s?xatilis ) early life stages impinged

on a continuously operating fine mesh traveling screen (2.

5-rom mesh) and

to determine the effectiveness of this device in screening organisms which

would otherwise be eqtrained.

Once-through cooling water systems used at steam electric generating stations use large amounts of water to cool the condensers. 

When in full

operation, the two units at Indian Point' pump approximately 6,

360 m

, (1. 68 million gallons) of water per minute through the condensers.

Aquatic organisms are carried along with this water through the cooling

water system where they may be exposed to abrupt temperature changes,

changes in h:,' drostatic pressure, mechanical buffetinp; and velocity

shear force.

The Consolidated Edison Company of New York (Con 

Edison) has been experimenting with a new screen designed to filter out entrainable ichthyoplankton. Con Edison has installed a continuously operating fine mesh

traveling screen at Indian Point Unit 

1 to determine its effectiveness in

reducing entrainment effects on Hudson River striped bass and other species as well as enhance impingement survival.

The two basic aspects of the study were to 

(1) determine the collection

efficiency of the screen, and (2) determine the survival of the impinged

organisms. The study was conducted during June 1977, when peak concentrations of striped bass larvae are found in the Hudson River.

'Unit 1 has not operated for commercial production since 

1974. Unit

2 is owned and operated by Con Edison. Unit 3 is owned by the Power

Authority of the State of New York and operated by Con Edison.
SUMMARY

Results of this study indicate that a continuously operating fine mesh

traveling screen (2. 5-mm mesh) of the design tested does not effectively

prevent entrainment of striped bass post-yolk-sac larvae 7-9 mm in length.

Late post-yolk-sac larvae ranging in length from 10 to 18 rom (mean length,

15mm) may be the minimum-sized larvae successfully diverted by the fine

mesh traveling screen.

Initial survival of late post-yolk-sac striped bass larvae impinged on

the fine mesh screen was estimated to be 68 percent at water intake velocities of 0. 4 fps and screen travel rate of 10 fpm. Survival of late postyolk-sac larvae to 96 hours after collection was 47 percent. Initial survival and survival to 96 hours of early juvenile 17 to 23 rom in length

(mean length 19 rom) were 100 and 88 percent , respectively. The high surviival of impinged juveniles indicates that the fine mesh traveling sci'een

could have significant potential to reduce entrainment impact on this life

stage. :r. qt;-~r'""

/00

a.k P- y-s

eo..r~jVv f

?;:

C?~

2-1
.._

.,__,

.,.L

.., ,....,,_._.._..,.. ....,,,...

SITE DESCRIPTION

The Indian Point Generating Station is located on the east bank of the

Hudson River , 69 river kilometers (43 mi. ) north of the Battery. A detailed description of the facility ~nd the Hudson River is given elsewhere

(Con Edison 1977a).

The intake structure at Indian Point Unit 1 is of particular interest in

this research. Unit 1 has not operated since 1 October 1974; thus, the

intake structure provides a suitable apparatus for investigation of new

designs. The intake system includes two circulating pumps , e~cp capable

of pumping 530 m3/minute (140 000 gpm) of water. Each pump draws water

from two intake forebays; thus, at full capacity, 265 m3/minute (70 000

gpm) of water enter Forebay 11 at Unit 1. At full c~pacity water intake

velocity is 0. 9 fps at the intake forebays.

tixed scr~en (9. 5-mm (3/8-in. J mesh), a bar rack, and a traveling screen

(9..,S""mm (3. 8:'In~J mesh) conventionally were used to ensure that large

fish, debris, and other objects were not pumped through the plant. For

this study a continuously operating fine mesh (2. 5-mm) traveling screen replaced the conventional traveling screen (Figure 3-1).
ELE'I.

, UNIT 1

2 CIRCUlJ\TING

PUMPS

611 gpm

-17' 7" ,

CONDENSER

!RCUU\TING

\'IA TER PUMP

25 ' a" i%r

TRA V ELI NG

SLOT FDR SCREEN (F!NE 

MESH.)

SLOT FOR TEMPORARY

DEWATERING SCRE~~

BULKHEAD

.. . 

Figu,. 3-1. Cross-sectional view of Indian Point Generating Station Unit 1 showing

location of fine mesh traveling screen. (Source: Con Edison 1977bl
METHODS AND MATERIALS

FINE MESH SCREEN

The conventional traveling screen was modified by removing the wire mesh

panels and replacing them with -mm mesh n~loD- screening cloth. The

screen was further modified to operate continuously at speeds from 2. 5 to

20 ft per minute. .(ish b!!"'Q. ets were added which spanned the width of the

screen (10 ft) to enhance survival of impinged organisms. A low-pressure

wash (148 gpm at 20 psi ; 182 gpm at 32 psi) , located at the top rear of

the screen ~emoved rmpinged organisms from the screen. Fish were washed

into a fiberglass trough where an auxiliary water system maintained a

water flow in the trough suitable for fish survival. A high-pressure

wash , located below the fish trough , removed debris from the screen. Fish

entering the trough were carried by the water flow via a sluiceway to a

bypass where they returned to the river.

During all tests, circulator pump number 11 was operated at 50 percent

capacity (70, 000 gpm), and the traveling screen was operated at a speed of

10 ft Del' minute Low-pressure screen washwater was set at 30 gpm (flow)

with auxiliary water turned off. This provided approximately 2 in. of

water in the trough at all times , which ensured that fish were not being

washed into a dry surface. These settings were held constant throughout

the study and no effort was made to optimize the operation of the screenwash system for maximum efficiency and survival.

COLLECTION DEVICE

Fish larvae and juveniles impinged on the fine mesh traveling screen were

collected by diverting the water from the sluiceway into a collection apparatus. The collection device consisted of a 505-~ mesh net in the shape

of an inverted cone suspended in a cylindrical tank filled with water

(Figure 4- 1). The bottom (wide portion) of the conical net was fastened

to a modified funnel, the neck of which exited the tank at the bottom.

Tygon tubing (5, ft long, 1- 1/4 in. diameter) was fastened to the neck of.

the funnel outside the tank. The level of water in the tank was maintained by a 3-in. drain pipe affixed with a standpipe and gate valve.

Diverted sluiceway water containing the impinged organisms entered the

tank inside the conical net. No flow was allowed through the funnel and

tygon tube drain during sampling, thus all water flowed through the net

and out the 3-1n. drain, thereby filtering out all organisms.

At the end of a sample period, the diverted flow was shut off and the tank

was allowed to drain. The net was thoroughly washed down with a fine

spray to remove all collected organisms. These organisms exited the tank

via the Tygon tubing drain, into a collection container fastened to the

opposite end. The containe~ consisted of a 24-x- 13-x-5-in. rectangular

plastic box with a fastened lid which was modified with screened openings.

This allowed excess water to flow from the container and further concentrated the collected organisms. The container was detached from the Tygon

tubing drain and transported to the onsi te laborato~y.
1 ft.

Conical Net

Funnel

Tygon Tubing 3-1n. Discharge Pipe

Figure 4-1. Collection dewice used for fine mesh traveling screen studies

at Indian Point.

Sluiceway

(Water from Screen)
COLLECTION EFFICIENCY

To determine the collection efficiency of the fine mesh screen , a known

number of striped bass post-yolk-sac larvae, obtained from the Texas

Instruments (TI) hatchery, were released in front of the continuously operating traveling screen into Forebay 11 at Unit 1. The screen washwater

was diverted for TO minutes after the release, and the numbers of larvae

collected were enumerated. Observations of the screen were made before

and after the screen wash to determine the effectiveness of the wash.

Collection efficiency experiments were conducted on 7 June 1977, using two

groups of approximately 5, 000 and one group of approximately 10 , 000 post-

, yolk-sac larvae 14 , days of ag~._ e~!'l_ engtl:L'Lmm). A second efficiency

test was conducted on 14 ' June 1917 using an estimated 750 post-yolk-sac

larvae 21 days old (mean length 9 rom).

To determine if larvae were being lost in the sluiceway and/or the collection device , a control group of 25 hatchery post-yolk-sac larvae (21 days

old , mean length 9 rom) were introduced into the trough directly behind the

traveling screen. The screen washwater was diverted for 10 minutes and

larvae were enumerated. In addition , small particles (approximately 5 rom

diameter) of styrofoam were released with the larvae and were observed en

route through the entire system.

IMPINGEMENT SURVIVAL

The second aspect of the $tudy, to determine survival of impinged larvae

was conducted using wild Hudson River larvae. Collections of screen

washwater were made during periods when the ri ~er dens! ty of striped bass

larvae were known to be high , based on other ongoing studies (entrainment

viability) (Ecological Analysts 1917). Several collections of various

durations were made of screen washwater between the hours of 2020 and 2140

on 16 and 21 Juns 1971. The object of these collections was to obtain a

suitable number of organisms for survival determination. After collection, fish larvae and juveniles were transported to the onsite laboratory

and sorted immediately. Organisms were classified as to condition and

held for latent effects observations. Larval and juvenile fish were

classified as live, stunned, or dead, based upon the following criteria:

Li ve :

Stunned:

Dead:

swimming vigorously, no orientation problems

swimming abnormally, struggling, swimming on side

no vital life signs, no body or opercular movement, no

response to gentle probing.

Li ve and stunned fish were carefully transferred to separate holding containers (O. 9S-liter jar containing filtered , ambient river water) with a 

large-bore glass pipette.

,..:.. 

A maximum of five larvae were placed in each holding container, which was

aerated and maintained in an ambient water trough. Dead specimens were

preserved for later identification.

Live and stunned organisms from the initial sort were retained and

examined at 3, 6, 12, 24 , 48 , 72, and 96 hours after sample co~lection.

4-3
Any dead organisms were removed from the holding jars and preserved in vials. All organisms remaining alive after 96 hours were also preserved

and placed in vials.

After completion of latent effects observations all vials were delivered

to the Middletown ichthyoplankton laboratory where the species and life

stage identifications were made.

Control larvae and juveniles were also subjected to stresses associated

wi th the collection, handling, and holding processes of the experiments.

Striped bass larvae and juveniles to be used as controls were collected

from the Hudson River in front of the intake at Indian Point Unit 2 , using

, a pump/larval table. The nlarval tablen was modified from the ori~inal

design described by McGroddy and Wyman (1971). Alive fish collected in

this manner were held in the onsite latent effects laboratory for 48 hours

before being used as controls. Handling and holding procedures in the

laboratory during this period were identical to procedures used for test

organisms.

DATA ANALYSIS

Survi val of striped bass impinged on the traveling screen was calculated

in a manner identical to entrainment survival. Proportion surviving was

calculated as the ratio of organisms found alive to the total number collected:

PT ; nqmber alive (live + stunned)

total number

where

PT = total proportion surviving.

Live organisms were grouped with stunned in the analysis, as the al ternat1ve of including them in the dead category would be inappropriate.

The survival of test organisms is the product of the conditional probability of surviving impingement and the sampling process. Assuming there

1s no interaction between the two stresses

PT = PI x Ps

where

PI = probability of surviving impingement

Ps = probability of surviving sampling apparatus.

The survival of the control organisms is used as an estimate of Ps and

proportion surv1 vlng impingement can be determined by:

PI = !I
or expressed as percent survival:

Sr = x 100

where

SI = impingement survival.

Significant differences between proportions surviving of experimental and

control larvae were tested using a z test for comparisons between two proportions at a = 0. 05 (Ostle and Mensing 1977: pp. 133- 134). Confidence

intervals on proportion surviving were determined according to Ostle and

Mensing (1977: pp. 100- 101).
RESULTS

COLLECTION EFFICIENCY

Collection efficiency experiments using 14-day-old post-yolk-sac hatchery

striped bass larvae indicated that larvae of this age (mean length of 7

rom) were not impinged on the traveling screen (Table 5- 1). Following release of two groups of approximately 5, 000 and one group of approximately

10, 000 post-yolk-sac hatchery larvae directly into Forebay 11 at Unit 

only 34 dead larvae were recovered in the three 10-minute samples (3 of

these were wild clupeid larvae). Most of the styrofoam released along

with the larvae as an indication of collection efficiency was observed in

the collection apparatus within 3 minutes after release. Of the 25 control larvae released directly into the sluiceway behind the traveling

screen, 23 were recovered in the collection container, indicating high

recovery by the sampling gear after lar' iae enter the sluiceway.

Experiments using 21-day-old post-yolk-sac hatchery striped bass larvae

(mean length 9 mm) indicated low collection efficiency by the fine mesh

screen for this size group. A total of 3, 229 larvae (approximately 4 percent of the initial number released) were recovered from a 10-minute collection of screen washwater following a release of approximately 

750

larvae directly in front of the screen (Table 5- 1). The number' of larvae

recovered were enumerated directly and consisted of 3 alive, 3 stunned,

and 3, 223 dead. The number of larvae released in front of the screen was

estima ted using a subsampling procedure. Of the total larvae released, it

was estimated by subsampling that 80 percent were dead and 20 percent were

alive at the time of release. The larvae were apparently stressed at the

time of release due to handling and holding, and these data should not be

used for survival estimates. However, these data were used to indicate

collection efficiency.

SURVIV AL ESTIMATES

The total organisms collected for impingement survival analysis are shown

in Table 5-2. A ' total ~f 119 wild striped bass Morone saxatilis ) were

collected during the study for survival estimates. Of the striped bass

collected, 103 were late post-yolk-sac (length range 10 to 18 mID, mean 15

mm) and 16 were classified as juveniles (length range 17 to 23 mm, mean

19 mm). In addition, several other species were collected, the majority

being Atlantic tomcod Microlladus tomcod ) juveniles. The tomcod averaged

59 nun in length. Only a subsample of the larger juveniles was retained

for survival observations.

Prooortion Survi viall Imoinllement and Collection

Initial and 96-hour survivals of each species collected by the fine mesh

traveling screen are shown in Table 5-3. Initial and 96-hour survivals of

late post-yolk-sac striped bass larvae were 68 and 47 percent, respectively.

Initial and 96-hour striped bass juvenile survivals were 100 and 88 percent, respectively. These estimates indicate survival after experiencing
TABLE 5- RESULTS OF FINE MESH TRAVELING SCREEN COLLECTION

IEN REL N 7 AND 14 JUN q77

Mean

Number Length Number Recovered

~lease ease rom

000 15(a)

000

000

25(b)

78, 750(0) 223 3 , 229

(a) Not all Marone

(b) Controls , released in sluiceway.

(0) 260 dead, 14 490 live.
TABLE 5- TOTAL NUMBERS AND MEAN LENGTHS OF EACH TAXON AND LIFE STAGE

COLLECTED FOR SURVIVAL DETERMINATIONS AT THE FINE MESH

TRAVELING SCREEN. JUNE 1 g77

Post-Yolk-Sac LaI"vae Jqveniles

Mean Mean

Number Length Number Length

xon Collec (mm) ollec (mm~

Striped bass 103 ' 5

(Marone ati)..is

White perch

(Marone mericana

Unidentified Marone

(Morone spp.

Bay anchovy

nch itchilli

Herring

(Clupeidae)

Atlantio tomcod

MicroQ:adus cod

Bluefish

matomus saltat

Rainbow smelt

(Osmerus ordax

Note: Dashes indicate no length recorded.
TABLE 5-3 INITIAL AND 96-HOUR SURVIVAL OF EACH TAXON AND LIFE STAGE COLLECTED AT THE FINE MESH

TRA VELllill SCREEN AT INDIAN POINT. JUNE 1977

Yolk aUlIJ:.'i -lIl Y.C.IlJ.le:l

Sample Prooortion Allve (a) Sample ProQQct 1o.n..Al1Y. e.

Speoles ~b.CL -----1nlt.lA1- q6- -.S.1ZL Initial q6-

Striped bass 103 68 (0. , 0. 71) ~7 (0. 37, 0. 51) 1.00 88 (0. , 0. 99)

While perch 113 (0. 12, 0. 02) 1~ (0. 01, 0. 61) 1.00Bay anohovy 86 (0. , 1. 00)

Bluefish 61 (0. 09, 0. 99)

To.ood 67 (0. , 0. 81)

Rainbow amelt. 17 (0. 00, ' 0. 64)

IIerring 33 (0. 01, 0. 91)Controls

Striped baIlS 1.00 80 (0. , 0. 96) 1.00 96 (O.BO, 1. 00)

WhIle peroh 1.00 83 (0. 36. 1. 00)

(a) Proportion alive oaloulaLed uaing live plua atunned organisma

(numbers In parentheaes Indicate 95 percent confidence Intervals

fr08 Oatle and Hanaing 1917).
impingement, collection, handling, and holding. Initial and 96- hour survi vals of 15 control striped bass larvae were 100 and 80 percent, respectively (Table 5-3). Initial and 96-hour survivals of 25 control striped

bass juvenile~ were 100 and 96 percent, respectively. These estimates

indicate percent surviving after experiencing collection, handling, and

holding.

Latent survivals of experimental and control groups of striped bass larvae

are shown in Figure 5- 1. Although the experimental larvae appeared to die

off more rapidly than controls in the beginning, no significant difference

(a = 0. 05) in proportion surviving occurs at 96 hours. Of the 11 stunned

larvae in the experimental group, all died wi thin the first 24 hours

(Appendix A). Latent survival of striped bass juveniles was similar for

experimental and control groups throughout the observation period (Figure

2) .

Numbers of fish initially classified as live, stunned, or dead, and those

live and stunned surviving for periods up to 96 hours , are given in Appendix A. These data can be used to determine proportion surviving at any

time period after collection. Initial proportion surviving of any species

can be calculated as live plus stunned, divided by the total collected for

that species. Survi val at any time after collection can be calculated for

live, stunned, or live plus stunned, as desired.

ElL tJ 1IIa_t _e _ J:LL!mID. lllte.rnJill_ Su rv i val

The effects of impingement alone on striped bass survival were estimated

using control and experimental results. Control survival was calculated

based on those fish subjected to collection and handling alone. Experimental survival was calculated based on fish subjected to impingement and

associated effects of the traveling screen plus collection and handling

effects.

Impingement survival estimates for striped bass larvae were made using

both initial and 12-hour survival data. Estimates were made at both time

intervals since the proportion of larvae surviving both initially and for

periods up to 48 hours were significantly lower (a = 0. 05) for the experimental group than for the controls. The reasons for choosing the 12-hour

data are given in the discussion. Survi val of impinged striped bass larvae was estimated to be 68 percent using initial data , and 60 percent

using proportion surviving 12 hours after collection. Survival of

impinged striped bass juveniles was estimated using initial data since

latent survival was similar for control and experimental groups. Survival

of impinged striped bass juveniles was estimated to be 100 percent.

5-5
1001 x

I 1

, CQ

...

::J

11.

'" Control

'" Experimental

'" 95 Percent Confidence Interval

Time Since Collection (I1r) ,

Figurlt 6.1. Latent survival of striped bass larvae collected -at the fine mesh traveling screen

at Indian Point, June 1977.

100
tI)

100 xa xa

x = Control

"" Experimental"" 95 Percent Confidence Interval

Time Since Collection (hr)

Figure 6-2. Latent survival of striped bass juveniles collected at the fine mosh traveling screen

at Indian Point, June 1971.

100
DISCUSSION

The results of this study indicate that a continuously operating fine mesh

, traveling screen (2 . 5-rom mesh) does not efficiently prevent entrainment of

striped bass post-yolk-sac larvae 7-9 mm in length. Very few early postyolk-sac hatchery larvae (7-9 mm in length) were impinged when released

directly in front of the screen. Based on collections of wild river larvae, late post-yolk-sac larvae ranging in length from 10 to 18 rom (mean

length 15 rom) may be the minimum size larvae successfully excluded by the

fine mesh traveling Screen. The length frequency distribution of striped

bass larvae collected from the fine mesh traveling screen is shown in

Figure 6- 1. Also shown is the length frequency distribution of 116

striped bass larvae that were collected by pumps during other studies in

the same time period at Indian Point Units 2 and 3 intakes. In the sample

collected from the fine mesh screen 60 percent of the larvae were over 15

rom in leng~h. However, in the sample collected by the pumps only 17 percent of the larvae were over 15 rom in length. Assuming that the lengthfrequency distributions of the larvae collected by the pumps represent the

length distribution of larvae in the river at the time of the study, then

this size distribution shift indicates that the fine mesh traveling screen

selectively diverts larger larvae (over 15 rom) but allows entrainment of

most smaller larvae (less than 15 mm).

Impingement survival estimates of latepost-yolk-sac striped bass larvae

ranged from 60 to 68 percent depending on method of calculation. 

latent survival were similar for both control and experimental larvae

initial proportion surviving could be used to determine impingement

effects (68 percent survival). However , as Figure 5-1 indicates, latent

effects observations for late post-yolk-sac larvae show significantly

(a = 0. 05) lower survival of experimental larvae as compared to controls up to 48 hours after collection. No significant differences

(a = 0. 05) were found at 72 and 96 hours after collection. Figure 5-

shows that the survival rate of experimental larv~e was about constant

from 3 to 12 hours after collection. The decline in survival of experimental larvae between 12 and 24 hours was probably not attributable to

impingement effects alone since latent survival of controls also declined

to the same level in the later portion of the holding period. Thus, survival of experimental larvae Just prior to this unexplainable decline (at

12 hours) was selected as the best lower estimate of impingement survival

(60 percent).

The results ofth1s study indicate a potential for high survival (100

percent) of early striped bass juveniles (19 mm in length) impinged on the

fine mesh traveling screen. However, all survival estimates were made on

larvae and juveniles successfully washed from the screen by the lowpressure wash. The possibility exists that some fish may have been impinged in such a way ("gilled") that they were not washed from the screen by the fine screen wash~ Such impinged fish would then encounter the highpressure wash and probably would not survive; however, observations of the

screen after the tine wash showed no remaining impinged fish.
::I

...

::I

C.J

C.J

::.

C.J

::I

...

Fine mesh screen

Pumps

Total Length (mm)

Figure 6-1. Length. frequency of striped bass larvae impinged on a fine mesh

Uaveling screen compared to those collected by pumps

(16 June 1977 through 21 June 1977).
No problems were encountered with debris during the fine mesh traveling

screen studies. However , circulator pump 11 was only operating at 50 percent capacity. Since only half the flow of this pump enters Forebay 11

only 132 m3 (35, 000 gallons) per minute were flowing through the screen.

Intake water velocity at this flow was 0. 4 fps. No tests were conducted

at full pump capacity, which would create an intake water velocity of 0.

fps.

The usefulness of a fine mesh traveling screen to prevent entrainment loss

should be determined by comparing mortality associated wi th entrainment to

that of impingement on the fine mesh screen. The results of this study

indicate a potential for 100 percent survival of impin~ed striped bass

juveniles. If this is an accurate estimate of impingement survival, the

fine mesh screen design may provide a means of reducing entrainment

impact.

6-3
REFERENCES

Con~olidated Edison Company of New York , Inc. (Can Edison). 1977a.

Indian Point Unit 2 , Indian Point Unit 3. Near-field effects of oncethrough cooling system operation on Hudson River biota. Consolidated

Edison Company of New York, Inc., Power Authority of the State of New

York. July 1977.

Consolidated Edison Company of New York, Inc. (Con Edison). 1977b.

Influence of the proposed Cornwall pumped storage project and steam

electric generating plants on the Hudson River Estuary with emphasis on

striped bass and other fish populations. Edited by J. T. McFadden.

February 1977.

Ecological Analysts , Inc. 1977. Indian Point Generating Station Entrainment Survival and Related Studies. 1977 Annual Interpretive Re- port. In preparation.

McGroddy, P. N. and R. L. Wyman. 1977.

vice for sampling living fish larvae.

Can. 34:4. pp. 571, 574.

Efficiency of nets and a new deJournal of the Fish. Res. Bd. of

Ostle, Bernard and R. W. Mensing. 1977. Statistics in Research , Third

Edi tion. Ames , Iowa. The Iowa State Uni v. Press.
APPENDIX A

RAW DATA

, ,. ..
Table A- l gives numbers of each species and life stage collected during

this study. Numbers surviving are shown separately for live and stunned

organisms throughout the latent effects observations period. Thus, pro~ portion surviving a t any time interval can be calculated using live stunned, or live plus stunned organisms. Table A-2 gives the same information for control groups of striped bass and white perch.

, .

A-1
TAm.1! A- I HUHU~nS OF FISIf LARVAl:: AND JUV~NILES SURVIVING TO 96 IIOUkS AfT!::!1 IHPltila-:.HUIT (,11 " C\:!lTl~. U\ U" OPERATING FINE MESH TRAVELING SCREEN INCLUDING EFFECTS ASSOCIAT~D WITH SAH~LE COLLECtiON AND

HANDLING

l.ca ;t~,l D(O)

...3=bL.. 12- 211- ....ll::b~ 1Z:hL SDCctes He.. J... J..... J..... J... L... J.....

1.aau

; ;

119 116 t!2t2JlA nuUl14 american,

t!2I:Q11C speoles

Clupel4ae (raally)

JIU!IKIA mllDb llU

.IJJJ c n1U

Mw:wIJl JlAUUllA Iii

HQrQnSl .Ia1Uc1QAQA

M2cQDJI species

Jrutltt!iI ~llill.aIllilLQIIIUIi nlt./I.ld..&

MliU:Qlull11a lQII~

D:I~ I:W ll2r!1u

Clupeldae (ra.lly)

(a) L Indicates llye.

(b~ S Indloatea atunRed.(0) 0 Indloatea dead.
TABLE A- NUMBERS OF CONTROL LARVAE AND JUVENILES SURVIVING TO 96 HOURS AFTER EXPERIENCING ONLY

SAMPLE COLLECTION AND HANDLING EFFECTS 

InlPt~ -Z!d1~ .Ji IY1L L(a)

1... 1.... a.. 1... 1.... 1.-. 1... .L.... SD8cl811 Nalle

J&DU

111 tmwlA nut..1lJ.A

.tku:2nA AJW:1Ja D&

.luvMllA

t\Qf:onc nnt.Ula lIerlcana

(a) L Indicates Jive.

(b) S Indicates stunned.

(c) D Indicates dead.

Hclol 60 oraanlsme released . 56 recovered.