14' 9 

fP- ?6"

. .

ICHTHYOPLANKTON MONITORING STUDY

DEPLOYMENT OF A GUNDERBOOM SYSTEM AT

LOVETT GENERATING STATION UNIT 3 

1998

Final Report

Prepared for:

Orange and Rockland Utilities

One Blue Hill Plaza

Pearl River, New York

Jointly funded by:

Central Hudson Gas and Electric Corporation

Consolidated Ellison Company of New York, Inc.

New York Power Authority

Niagara Mohawk Power Corporation

Orange and Rockland Utilities, Inc.

Prepared by:

Applied Science Associates

291 County Rpute 62

New Hampton, New York 10958

January 1999
Applied Science Associates

INTRODUCTION

Orange and Rockland Utilities (ORU) has been investigating the practicality and efficacy

of using a physical banier technology (Gunderboom) as a means of reducing the loss 

fish eggs and larvae resulting ITom cooling water withdrawals at the Lovett Generating

Station. These investigations are part of an understanding between ORU, the New York

State Department of Environmental Conservation, and the Hudson Riverkeeper Fund

Inc. This Gunderboom System consists of a porous fabric material made with a nominal

mesh opening of212 microns. The fabric is designed to serve as a banier system to

prevent entrainable organisms from entering the cooling water system along with the

cooling water flows.

Previous deployments oftms system in 1996 and 1997 were principally designed to

evaluate the engineering practicality of system deployment in the tidal Hudson River

estuary. In 1998, a one-month entrainment sampling program was conducted coincident

with system deployment. The results of this sampling demonstrated a greater than 80

percent reduction in the density of entrainable organisms entering the cooling water

system attributable to the Gunderboom System (EA 1998).

The purpose of this study was to further evaluate the effectiveness of the Gunderboom

System in reducing the number offish eggs and larvae entrained across an entire

entrainment season. This evaluation was conducted by comparing the density 

entrainable organisms behind the Gunderboom System to the density in adjacent areas

unprotected by the System. Differences in the densities in pair samples is a measure 

the potential effectiveness of the System ill reducing the entrainment offish eggs and

larvae in the cooling water system at the Lovett Generating Station.

METHODS AND MATERIALS

" The Lovett Generating.station is located on the west bank of the Hudson River estuary at

River Mile (RM) 42, just north of Stony Point, New York This station consists of three

fossil-fueled, steam electric units, having net generating capacities ranging from 63 to

202 MWe for a total of463 MWe for aU units combined. Owned and operated by ORU

Unit 3 began commercial operation in March 1955, Unit 4 in May 1966, and Unit 5 in

April 1969. Two other units, 1 and 2, were retired in January 1996.

For this study, the Gunderboom System was installed to provide protection to the Unit 3

intake. This system consists of approximately 500 feet offabric material deployed in a

semi-circle symmetrically around the intake. . This barrier is anchored to the bottom with

concrete blocks and attached to large floats providing filtration to all cooling water

entering the Unit 3 intake. TIns System was deployed on 11 June 1998 and remained in

place throughout the duration of this study. During most of this study, the fabric was

Gunderboom System Biological Eva/uaiion

Final Report

01108/99
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Applied Science Associates

routinely cleaned with an air-wash system to prevent build-up of silt. Towards the end of

the study, no maintenance was performed to determine untended behavior of the system.

For the Gunderboom evaluation assessment, simultaneous entrainment sampling was

conducted at the Unit 3 intake that was protected by the Gunderboom System and at the

Unit 4 intake that was unprotected. Sampling was conducted on two nights per week

from 11 June through 31 August with the exception of the period of 11 - 19 August.

Paired samples of approximately 20 minutes duration were collected at each intake

sequentially at three depths (surface, mid-depth, and bottom) during each of 5 sampling

events conducted between 7 p.m and 7 a.m the following morning for a total of30

samples each sampling date. Owing to system deployment and sampling logistics

sampling on the first night (11 June) was limited to 2 events and sampling was alternated

between Unit 3 and Unit 4. In addition to the routine nighttime sampling, sampling also

was conducted during 2 daylight periods (7 July and 6 August) following the same 5-

event/3-depth design used at night. A total of702 individual 20-minute samples were

collected during the course of this study.

Each sample was collected using a standard netlbarrel, pumped entrainment sampling

system. Water and entrainable organisms were pumped to the sampling device using 2

Honda 4-inch trash pumps with a rated capacity of 500 gpm. One pump was used to

sample each intake location. Volume sampled was monitored using a Signet digital

flowmeter and recorded for each sample on the field sampling data sheet. Volume

sampled across the entire study ranged from approximately 22 to 29 m3 per sample with

an overall mean of23. 2 m3 at both units.

From the pump, water flowed to one of two entrainment samplers, each ofwhich

consisted of a 275 gallon plastic tank into which a plankton net was placed (Figure 1).

Each plankton net was 42 inches long consisting of 505 11m nylon netting which was

attached to a Stainless steel hoop of30 inches in diameter. After each sample, the nets

were carefully washed down and all retained material w.as remoyed fTom each collection

cup, transferred to glass sample jars, and fixed with 10 percent Formalin stained with rose

bengal for subsequent laboratory processing.

In the laboratory, all collected materials were removed from the sample jars. All fish

eggs and larvae were then carefully removed fTom other materials and preserved in 50

percent ethanol for subsequent identification. All egg and larval identifications were

made by an experienced ichthyoplankton taxonomist based on morphometric and meristic

characteristics as described in available scientific literature. All counts for each species

and life stage uom each sample were recorded on an appropriate laboratory data sheet

and entered, along with the field sampling information, into a computer database.

Glll1derboo!l1 s.vstem Biological Evaluafiol1

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RESULTS AND DISCUSSION

A total of 6 343 individual fish eggs, larvae, and early juveniles were collected during the

course of this study, 3 698 at Unit 4 and 2 645 at Unit 3 (Table 1). The majority of those

collected (68 percent) were bay anchovy; the most abundant ichthyoplankter in the lower

Hudson River estuary during summer months. Other abundant taxa were striped bass

river herring and naked goby. The remaining taxonomic groups together comprised less

than 3 percent of the total catch. Most of those collected (89 percent) were post yolk-sac

larvae with the remainder evenly split between eggs and early juveniles. Only 14

individuals identified as yolk sac larvae were collected in this study. All but 11 eggs

were identified as bay anchovy.

Overall daily mean densities'irlmged from less than 5 to almost 2 000 organisms per 1 000

3 (Figure 2). There were four periods of peak entrainment, early to mid-June (post

yolk-sac larvae), early July (egg and post yolk-sac larvae), early August (egg and post

yolk-sac larvae), and late August (early juveniles). On the two dates with full 24-hour

sampling (7 July and 6 August) densities were generally higher at night (especially near

mid-night) and much lower during the day (Figure 3). Across the entire sampling period

densities were higher at the bottom and lowest at the swface with densities at mid-depth

being intermediate (Figure 4). A similar seasonal pattern was evident at all depths and at

both units. Seasonal abundance patterns for each of the four most abundant taxa are

discussed below:

Bay anchovy 

Bay anchovy were principally collected from early July through late August (Figure 5).

Owing to their numerical abundance, the pattern in abundance for this species was similar

to that for all species combined over their period of occurrence. There were n\'o periods

of higher egg and larval abundance and one period of higher juvenile abundance. These

periods ofhighe.r abundance most likely reflect times oOnflux of more saline waters

from areas downstream ofthe station. A similar seasonal pattern in abundance was

evident for all life stages at both units.

Striped bass

No striped bass eggs and only 5 yolk-sac larval striped bass were collected during the

course of this study. TIle primary striped bass spawning period typically occurs prior to

the start of this study. Daily mean densities for post yolk-sac larv&l striped bass were

highest (~l 600 per 1 000 m ) in mid-June with much lower densities before and after

that date (Figure 6). A similar pattern was evident at both Unit 3 and Unit 4. Juvenile

striped bass were collected at much lower densities from mid-June through the end of

July. As with the earlier life stages, patterns in mean density were generally similar

between the two units.

Glmderooom System Biological Evaluaiion

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Applied Science Associates

River herring

Almost all river herring collected were post yolk-sac larvae. Eggs were only collected

during the first sampling interval and only at Unit 3. Peak density for the post yolk-sac

stage was just after mid-June and few were collected after the thUd week in June (Figure

7). The seasonal pattern was generally similar between Unit 3 and 4. The few juveniles

collected in mid- to late June. River herring generally spawn in the upper reaches of the

tidal Hudson and in tributary streams. Thus, they typically enter areas of the estuary near

Lovett only as late larvae or older stages.

Naked goby

Naked goby were only collected as post yoLk-sac larvae and early juveniles. This

summer-spawning species produces adhesive eggs in guarded nests. Consequently, it is

only during the later larval stages that this species becomes planktonic and, thus

entrainable. Both post yolk-sac larvae and early juveniles were collected in July and

August with peak densities in early August (Figure 8). Seasonal patterns for both life

stages was similar at Unit 3 and 4.

Comparison between Unit 3 and Unit 4

Seasonal patterns in overall density of all life stages combined were similar between

Units 3 and 4 (Figure 9 - top). Daily mean densities at Unit 3 which was protected by the

Gunderboom system were lower than that at Unit 4 (unprotected) ITom the second

sampling date through mid-July. Thereafter, mean densities at the two units were

generally similar, with the exception of a period in early August when collections were

dominated by post yolk-sac larval bay anchovy and naked goby and mean densities were

considerably higher at Unit 3.

The ratio of daily mean densities at Unit 3 to densities at Unit 4 can be used as a measure

of the effectiveness of the Gunderboom system as deployed at Unit 3. This ratio

exhibited a rapid decline during the first 2 sampling intervals reaching 0.26 on 18 June

(Figure 9 - bottom). Thereafter, the ratio remained relatively low though 13 July with

the variability evident over this interval most likely a result of the low collections over

this interval. Overall average reduction in ichthyoplankton densities at Unit 3 compared

to Unit 4 over the LTJ.terval18 June through 13 July was 76 percent. Beginning in mid.

July this ratio began to increase reaching approximately 1 (i. , no difference in densities)

on 20 July. Thereafter, this ratio exhibited considerable variability ranging from a high

of2.65 on 3 August to a low of 0.08 on 27 August. Across the period 16 July through 31

August, densities actually averaged 4 percent higher at Unit 3 than at Unit 4.

Gunderboom System Biological Evaluation

Fil1al Report

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Applied Science Associates

OveraIl, the results ofthis study revealed seasonal patterns in abundance and species

composition consistent with that expected based on previous studies and general

knowledge regarding spawning habits of many of the common species. Collections at the

beginning of the study were dominated by two common spring-spawning groups, striped

bass and river herring whereas later collections were dominated by the two summerspawning species, bay anchovy and naked goby. Most of the entrainment occurs during 

relatively short period at night. Seasonal abundance patterns at both units and across

depths were similar. During the early part of this study, the Gunderboom system

appeared to result in significant reductions in entrainment densities at Unit 3. The

magnitude of this reduction was similar to that reported in previous system tests. This

reduction was evident soon after deployment of the system following a short time during

which ichthyoplankton trapped behind the barrier were gradually depleted through

entrainment. However, it appears that sometime in middle to late July, something

happened to the Gunderboom system that substantially reduced it' s effectiveness (LMS

1998), such that entrainment densities at the two units after this time were generally

similar.

REFEREN CES

EA Engineering, Science and Technology. 1998. 1997 Ichthyoplankton Entrainment

Monitoring Study at Lovett Generating Station. Prepared for Orange and Rockland

Utilities, Inc.

Lawler, Matusky, and Skelly Engineers, LLP (LMS). 1998. Lovett Generating Station

Gunderboom System Evaluation Program 1998. Prepared for Orange and Rockland

Utilities, Inc.

Gunderboom System Biological EvaluaiiOl1

Filial Report

01/08/99
Applied Science Associates

Gunderboolil System Biological Evaluation

Final Report

TABLES

01/08/99
Applied Science Associates

TABLE 1. OVERALL SPECIES COMPOSITION IN ENTRAINMENT SAMPLING AT THE LOVETT GENERATING

STATION, 1998.

UNIT4 UNIT 3 

SPECIES EGG YSL PYSL JUV UNtO Unit Total EGG YSL PYSL JUV Unit Total

Bay anchovy 232 176 153 565 618 733

Striped bass 743 803 492 527

River herrina 131 133

Naked qobv 234 246

White perch

Weakfish

American shad

Morone SOD.

Cyprinid unid.

Tessellated darter

Menidia sOP.

Centrarchid unid.

American eel . 1 

V\lhite suckerClupeid unid. 

, Windowpane flounder

Unidentified qobv

Hoqchoker

Atlantic tomcod

Unidentified

Northern pipefish

Totals 233 207 240 698 432 159 645

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c:J

:::" t::t:::.~;a ~

c:r-

\. 

::'2 g

. C/:)

;:;

;:i

(;:) ....

f')is"

i.::
Entire Sampling Set-up

Close-up of Barrel Samplers and Net

. .

Close up of Pump and Flowmeter

Close-up ofNct in Barrel

Figure 1. Photographs of entrainment sampling equipment used

at the Lovett Generating Station, 1998.
. .

Eggs

3 oo

250

Unit 4 

Unit3

... 2oo

4.1

~ 150

~ 1oo

... .

0 .

6/11 6121 7/1 7/11 7121 7131 8110 8120 8130

Date

Post Yolk Sac Larvae

000 -Unit 

1,800

    

Unit 3

600

. ...

400

 

~ 1,200

C!I A 1,000

1:1 800

CII 600

400

200

6/11 6/21 7/1 7/11 7f21 7131 8/10 8/20 8130

Date

Juveniles Unit 4

250

    

Unit 3

~ 200

...

CII 150

~ 100

6/11 6/21 7/1 7/11 7/21 7131 8/10 8/20 8130

Date

Figure 2. Seasonal pattem in daily mean entrainment density for all taxa

combined at the Lovett Generating Station, 1998.
400

200

000

800

1:1 600

500

000

;;;1,500

c:.J

c:.J 1 000

400

200

soo

Figure 3.

.. . .. .. .. . 

7 .July

Urn! 4

... -Unit3

.. . ,

Hour

6 Augus t

Urn! 4

. 

Unit 3

....

Hour

Diel pattern in mean entrainment density for all taxa combined

at the Lovett Generating Station, 1998
Surface

4,500

000 Unit 4 

500

Unit 3

.... 3000

~ 2~00

= 2,000

41 1,500

~ 1 000

500

6/11 6121 7/1 7/11 7121 7/31 8110 8120 8130

Date

Mid-Depth -Unit 500

000

. . 

Unit 3

500

.... 3 000

u 2 500

= 2,000

. \

c.su 1,500

~ 1 000

500

. _ ... \

6/11 6/21 7/1 7/11 7121 7/31 8110 8/20 8/30

Date

Bottom Unit 4 

500

000

    

Unit 3

500

.'" 3, 000

u 2,500

= 2,000

.

~ 1,500

:E 1 000

500

~ I

6/11 6/21 7/1 7/11 7121 7/31 8/10 8120 8/30

Date

Figure 4. Seasonal pattern ill daily mean entrainment density by depth for

all taxa combined at the Lovett Generating Station, 1998.
, .

300

250

.... 200

~ 150

~ 100

6/11

400

1,200

t- 1 000

800

600

C'"'.

400

200

6/11

250

200

;g 150

~ 100

=s 50

6/11

Figure 5.

6/21 7nl

Eggs

::; 

7/21

Date

7131 8/10 8/20 8130

Post Yolk Sac Larvae

. ...

-Unit4

. 

Unit 3

6/21 7/1 7/11

6/21 7/1 7/11

7/21

Date

7/31 8/10 8120 8130

Juveniles Unit 4

~ ~ - - Unit 3

7/21 7/31 8/10 8/20 8130

Date

Seasonal pattern in daily mean entrainment density for bay anchovy

at the Lovett Generating Station, 1998.
Eggs

...

4.1 A 0.

4.1

::s

Unit4

Unit 3

None Collected

7/1 7/11 7/21 7/31 8110 8/20 8/30

Date

Post Yolk Sac Larvae

1,800 -Unit4

600 . -- - - Unit 

400

... 

1,200

4) 1,000

800

. .

600

::s 400

200

6/11 6(21 7/1 7/11 7/Z1 7/31 8/10 8/Z0 8130

Date

Juveniles Unit 4 

. 

Unit 3 

~ 25

~ 20

= 15

Q.)

::s 10

\. . 

6/11 6/21 7/1 7/11 7/1.1 7/31 8/10 8/1.0 8/30

Date

Seasonal pattern in daily mean entrainment density for striped bass

at the Lovett Generating Station, 1998.

6/11 6/1.1

Figure 6.
Eggs

Unit 4 

~ 50

Unit3

...

~ 40

s= 30

6/11 6121 7/1 7/11 7121 7/31 8110 8120 8/30

Date

Post Yolk Sac Larvae Umt 4 250

. - - - - Umt 

200

....

!9 150

Go)

c 100

6/11 6121 7/1 7/11 7121 7131 8/10 8f20 8/30

Date

Juveniles Unit 4 

- - - - Unit 3

~ 2.

....

41 2.

1.5

co:

1.0

6/11 6111 7/1 7/11 7121 7131 8/10 8110 8130

Date

Figure 7. Seasonal pattern in daily mean entrainment density for river herring

at the Lovett Generating Station, 1998.
Eggs

,1.~"~"

Urn' 4

- - - - Unit 3

~ 0.

to:

None Collected

6/11 6/21 7/1 7/11 7/21 7/31 8/10 8/20 8/30

Date

Post Yolk Sac Larvae

400 -Unit 

350

Unit 3

t' 300

\

~ 250

A 200

~ 150

~ 100

6/11 6/21 7/1 7/11 7/21 7/31 8/10 8/20 8/30

Date

Juveniles Unit 4 

Unit 3

f' 10 ' I

. ,

6/11 6/21 7/1 7/11 7/21 7/31 8/10 8120 8/30

Date

Figure 8. Seasonal pattern in daily mean entrainment density for naked goby

at the Lovett Generating Station, 1998.
AllUfe Stages

000

1~800

600

400

.G- ~ 1,200

= 1,000

800

::s

600

400

200

6/11 6/21 7/1 7/11 7/21 7/31 8/10 8/20 8/30

Date

..,. ..

S 2

t")

13 2

.....

..g 1

6/11 6/21 7/1 7/11 7/21 7/31 8/10 8/20 8/30

Date

... ... ...

Urn' 4

. . .  

Unit 3

Figure 9. Comparison of entrainment densities at Unit 3 and Unit 4 of the Lovett

Generating Station, 1998.