# 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 1977TABLE OF CONTENTS

INTRODUCTION

SUMMARY

SITE DESCRIPTION 

### 4-1 

# 4. METHODS AND MATERIALS 

## 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 DATALIST 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.



### 111LIST OF TABLES

Results of fine mesh traveling screen collection effi

### ciency 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 operatingfine 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 sta

### tions 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 ichthyo

### plankton. Con Edison has installed a continuously operating fine mesh traveling screen at Indian Point Unit 1 to determine its effectiveness inreducing 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 onthe 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 m 3/minute (140 

### 000 gpm) of water. Each pump draws water from two intake forebays; thus, at full capacity, 265 m 3/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 1977blMETHODS 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 s 

## creen ~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 throughoutthe 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 werecollected by diverting the water from the sluiceway into a collection ap

### paratus. 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 concen

## trated 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 TexasInstruments (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 wascalculated as the ratio of organisms found alive to the total number col

## lected:

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 proba

### bility 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 andcontrol 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 per

### cent, respectively. These estimates indicate survival after experiencingTABLE 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 (Ma 

## rone 

## ati)..is
White 

## perch (Ma 

## rone 

## mericana

Unidentified 

### Marone (Mo 

## rone 

## 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 5-3INITIAL AND 96-HOUR SURVIVAL OF EACH TAXON AND LIFE STAGE COLLECTED AT THE FINE MESHTRA VELllillSCREEN AT INDIAN POINT. JUNE 1977YolkaUlIJ:.'i-lIlY.C.IlJ.le:lSampleProoortion Allve(a)SampleProQQct 1o.n..Al1Y. e.Speoles~b.CL-----1nlt.lA1-q6--.S.1ZLInitialq6-Striped bass10368 (0., 0.71)~7 (0.37, 0.51)1.0088 (0., 0.99)While perch113 (0.12, 0.02)1~ (0.01, 0.61)1.00Bay anohovy86 (0., 1.00)Bluefish61 (0.09, 0.99)To.ood67 (0., 0.81)Rainbow amelt.17 (0.00,' 0.64)IIerring33 (0.01, 0.91)ControlsStripedbaIlS1.0080 (0., 0.96)1.0096 (O.BO, 1.00)WhIle peroh1.0083 (0.36. 1.00)(a)Proportion alive oaloulaLed uaing live plua atunned organisma(numbers In parentheaes Indicate 95 percent confidence Intervalsfr08 Oatle and Hanaing 1917).

### impingement, collection, handling, and holding. Initial and 96- hour sur

## vi vals of 15 control striped bass larvae were 100 and 80 percent, respec

### tively (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 Appen

# dix 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 experi

### mental 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.



### 5-51001 xI 1, CQ::J...11.'" Control'" Experimental'" 95 Percent Confidence IntervalTime Since Collection(I1r) ,Figurlt 6.1. Latent survival of striped basslarvae collected -at the fine mesh traveling screenat Indian Point, June 1977.100tI)100xa xax =Control"" Experimental"" 95 Percent Confidence IntervalTime Since Collection (hr)Figure 6-2. Latent survival of striped bassjuveniles collected at the fine mosh traveling screenat 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 lar

### vae, 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 con

### trols 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 onlarvae and juveniles successfully washed from the screen by the low

# pressure wash. The possibility exists that some fish may have been im

## pinged 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 m 3 (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.

6-3REFERENCES

Con~olidated Edison Company of New York 

# , Inc. (Can Edison). 1977a. Indian Point Unit 2 , Indian Point Unit 

### 3. Near- field effects of once

### through 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 En

### trainment 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-1TAm.1! A- IHUHU~nS OFFISIf LARVAl:: ANDJUV~NILES SURVIVING TO 96IIOUkSAfT!::!1 IHPltila-:.HUIT(,11 " C\:!lTl~.U\ U"OPERATINGFINEMESH TRAVELING SCREEN INCLUDING EFFECTS ASSOCIAT~D WITH SAH~LE COLLECtiON ANDHANDLINGl.ca;t~,l D(O)...3=bL..12-211-....ll::b~1Z:hLSDCctes He..J...J.....J.....J...L...J.....1.aau; ;119116t!2t2JlAnuUl14american,t!2I:Q11CspeolesClupel4ae (raally)JIU!IKIA mllDbllU.IJJJ cn1UMw:wIJlJlAUUllAIiiHQrQnSl .Ia1Uc1QAQAM2cQDJI speciesJrutltt!iI~llill.aIllilLQIIIUIinlt./I.ld..&MliU:Qlull11alQII~D:I~ I:W ll2r!1uClupeldae (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 ONLYSAMPLE COLLECTION AND HANDLING EFFECTSInlPt~-Z!d1~.Ji IY1LL(a)~ ~1...1....a..1...1....1.-.1....L....SD8cl811 NalleJ&DU111tmwlA nut..1lJ.A.tku:2nA AJW:1Ja D&.luvMllAt\Qf:oncnnt.UlalIerlcana(a) LIndicates Jive.(b) SIndicates stunned.(c) DIndicates dead.Hclol 60oraanlsme released. 56 recovered.