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EFFECTIVEN ESS EVALUATION

OF A FINE MESH BARRIER NET .

. ..

LOCATED AT THE COOLING WATER INTAKE

OF THE BOWLINE POINT GENERATING STATION

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""""", "", mh, h..... h h.. .. m h ,.. "h hh.. ".. h.... m m"m.... ."..... h..".. mm"" .."m"...".. h.. "".....,... "h' h.. h.. h.. m".. ",m ""h h "'"h...... """h "" h, hh. mm.. "h h "... h "';m ..h..""", ,... "' 1'" '" ~..m '

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April 1994

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LAWLER, MATUSKY & SKELLY ENGINEERS One Blue Hill Plaza . Pearl River New York 10965

, (
&;J II;)

-rW- r..

a-U;j

/3'1/

F:! 

11:;:1'0 II 4t'" 11:91 

ORANGE AND ROCKLAND One Blue Hill Plaza, Pearl River, New York 10965

February 7, 1996

Mr. Edward Radl e

New York State Department

of Environmental Conservation

50 Wolf Road

Albany, NY 12233- 4756

Mr. Kenneth L. Marcellus

Con sol idated Edi son Company

of New York

4 Irving Place

New York, NY 10003

Mr. Wayne Elliot

New York State Department

of Envi ronmental Conservation

21 South Putt Corners Road

New Paltz, NY 12561

Mr. William Kirk

Con sol idated Edi son

of New York

4 Irving Place

New York, NY 10003

Company

Gentlemen:

Enclosed for review is Orange and Rockland Utilities, Inc. Research and

Development final report entitled Effectiveness Evaluation of a Fine Mesh

Barrier Net Located at the Cooling Water Intake of the Bowline Point

Generating Station. 

II Orange and Rockland believes a fine mesh barrier system

at the Bowline facility is a feasible mitigative alternative and will

continue to test its effectiveness in future studies.

If you have questions or comments, please call me at (914) 577- 2898.

Sincerely,

!./ /, /.

t-t.U IY~ -j). .).'J.-",,-:-.

!..

r----'"

William D. Saksen

Sr. Environmental Scientist

WDS: ag

Enc.

cc: R. Tummarello

T. Kosior

F. Mari no

Sun ivan

ES\ENV\ 96LETTER. W'DS\ 

ORANGE AND ROCKLAND UTILITIES. INc. PIKE COUNTY LIGHT &. POWER CO. I ROCKLAND ELECTRIC COMPANY

Pearl River, New Xork Mi!ford. Pennsylvania Saddle R!ver, New Jersey
April 1994

ORANGE AND ROCKLAND UTILITIES, INCORPORATED

Pearl River, New York

EFFECTIVENESS EVALUATION OF A FINE MESH

BARRIER NET LOCATED AT THE COOLING

WATER INTAKE OF THE BOWLINE POINT

GENERATING STATION

LMSE-94/0221 & 169/306

Prepared By:

LAWLER, MATUSKY & SKELLY ENGINEERS

Environmental Science & Engineering Consultants

One Blue Hill Plaza 

Pearl River. New York 10965
TABLE OF CONTENTS

Page No.

LIST OF FIGURES

LIST OF TABLES iii

1 REPORT SUMMARY

2 INTRODUCTION

1 Background

2 Objectives

3 SITE DESCRIPTION

1 Bowline Pond

2 Bowline Point Generating Station

4 DESCRIPTION OF FINE MESH BARRIER NET

1 Mesh Selection

Selection of Target Species

Mesh Size Selection

2 Net Design

3 Barrier Net Deployment

5 EVALUATION PROGRAM DESCRIPTION AND RESULTS

1 Evaluation Program Description

1.1 Water Velocity Profiles

Clogging and Biofouling

2 Program Results

Bowline Point Operation

Biofouling and Clogging Observations

Biological Monitoring

6 DISCUSSION AND CONCLUSIONS

1 General Program Description

Lawler, Matusky & Skelly Engineers
TABLE OF CONTENTS

Continued)

2 Phase II Program

Barrier Net Design Considerations

Barrier Net Deployment and Observations

Barrier Net Effectiveness Evaluation

3 Conclusions

REFERENCES CITED

IT ACHMENTS

1 - Bowline Pond Sediment Core Logs 26 April 1993

2 - Bottom Profiles - Bowline Pond in the Vicinity of BPGS Cooling Water Intake

3 - Test Frame Observation Information

4 - Cooling Water Intake Pump Entrainment Collection Information

5 - Bowline Point Plankton Net Samples Collection Information

6 - Bowline Pond Water Quality Information

7 - Total Length - Body Depth Measurements for Bay Anchovy

6-6

Lawler, Matusky & Skelly Engineers
Table No.

5-4

5-6

LIST OF TABLES

Title

Water Velocity Survey, Bowline Pond: 10 September 1992

Operating Characteristics of Bowline Point Generating Station

Circulating Water Pump Operation and Cooling Water Flow

Bowline Point Fine Mesh Barrier Net Evaluation Study

0 mm Mesh Test Panel Observation Information, Bowline Point

Fine Mesh Barrier Net Evaluation Study, July-August 1993

Water Velocity (cm/s) Recorded by Depth Behind the Fine Mesh

Barrier Net, July-August 1993

Species Inventory and Abundance by Location, Fine Mesh Barrier

Net Evaluation Study - 1993

Ichthyoplankton Concentration (No.llOOO ) Based on Intake

Pump Samples

Bay Anchovy Length Interval Information, Cooling Water Intake

Pump Samples

Ichthyoplankton Concentrations Based on 0.5 m Plankton Net

Samples Collected at Stations Inside and Outside the Fine Mesh

Barrier Net

Bay Anchovy Length Interval Information, Plankton Net Samples

Collected Outside the Barrier Net

Bay Anchovy Length Interval Information, Plankton Net Samples

Collected Inside the Barrier Net

Average Daily Water Quality Information, Bowline Point Fine Mesh

Barrier Net Evaluation Program

Bowline Point Fine Mesh Barrier Net Evaluation Study, Ichthyoplankton Collection Information, Bowline Point 0.5 m Plankton

Net - Special Samples

Page No.

5-6A

10A

IOB

IOC

IOD

11A

Lawler, Matusky & Skelly Engineers
Figure No.

4:-

4-4

LIST OF FIGURES

Title Following Page

Location of Bowline Point Generating Station

General Plan View of The Circulating Water System

Plan View of Intake Structure

Bowline Point Preliminary Design Plan View Fine Mesh Barrier Net

Bottom Profile Along Fine Mesh Barrier Net Deployment Transect

Bowline Point Fine Mesh Barrier Net Piling Installation Designation

and Measured Distances

Fine Mesh Barrier Net Deployment

Diagram of Entrainment Abundance Sampling System

O.5m Plankton Net Sample Transects 5-4

Lawler, Matusky & Skelly Engineers
CHAPTER 

REPORT SUMMARY

Orange and Rockland Utilities, Incorporated (ORU) has successfully deployed a barrier net

around the Bowline Point Generating Station (BPGS) cooling water intake structure to mitigate

fish impingement on the intake debris screens since 1977. The 9.5-mm mesh barrier net is

deployed on a seasonal schedule (mid-October through May) to cover the historic period of peak

fish impingement. Based on the effective use of the 9.5-mm mesh barrier net, ORU initiated

a program in 1992 to determine the feasibility of deploying a fine mesh barrier net to mitigate

entrainment.

Based on the results of some initial work conducted during 1992, and numerous conferences

between ORU and Lawler, Matusky & Skelly Engineers (LMS) personnel, it was concluded that

the best method to evaluate a fine mesh barrier net was to design, construct, and deploy a full

scale experimental net at the Bowline Point cooling water intake structure during the period

when ichthyoplankton were present. Monitoring the net would result in information on the

long-term feasibility of deploying and maintaining a fine mesh net, and the effectiveness of the

net could be determined by monitoring ichthyoplankton concentrations at locations inside and

outside of the net.

Since the bay anchovy larvae accounts for greater than 80% of the ichthyoplankton entrained

at BPGS , it was selected as the target species upon which to determine the effectiveness of the

fine mesh barrier net. six week test period from mid-July through August, which

encompasses the historic period of peak bay anchovy (post yolk-sac) larval abundance, was

selected. The experimental fine mesh barrier net would be constructed of nylon with 3.0 mm

mesh, and designed to be deployed around the BPGS intake using pilings.

The fine mesh barrier net test period extended from 19 July to 24 August 1993. During the

evaluation period several problems were encountered with net clogging and sinking. Initially

large numbers of immature jellyfish clogged the net, however, the principle net clogging

CFIO42294/11:22amlH22291 Lawler, Matusky & Skelly Engineers
problem was associated with very fine suspended silt. The net clogging problems were

countered by adding additional floatation to the net's surface line , and through in situ cleaning

using high pressure water sprays. Overall , monitoring the barrier net during the 1993 study

period suggests that, with scheduled maintenance, a fine mesh barrier net can be deployed at

the BPGS cooling water intake over the entire spring-summer period, Le. , period currently not

covered by the 9.5 mm mesh barrier net.

The concentration of ichthyoplankton in Bowline Pond during the 1993 fine mesh barrier net

evaluation study period was very low. The low ichthyoplankton abundance levels preclude the

determination of fine mesh barrier net effectiveness at limiting entrainment. Since the fine mesh

barrier net was successfully deployed over an extended period of time, the exclusion potential

of the 3.0 mm mesh net should be effective at limiting ichthyoplankton entrainment.

CFIO42294/11 :2bmlH22291 Lawler, Matusky & Skelly Engineers
CHAPTER 2

INTRODUCTION

BACKGROUND

Since 1977 Orange and Rockland Utilities, Incorporated (ORU) has seasonally deployed (midOctober through mid-May) a barrier net around the Bowline Point Generating Station (BPGS)

cooling water intake, a shoreline intake located on Bowline Pond, to limit fish impingement on

the intake traveling screens (Hutchison and Matousek 1988). The seasonal deployment period

corresponds to the annual peak impingement period at BPGS. The barrier net with nominal 9.

mm mesh has been shown to be very effective at mitigating fish impingement (NAI 1993).

As part of the Hudson River Utilities Settlement Agreement (1980) during the spring-summer

period , the Hudson River Utilities agreed to reduce water withdrawal rates at BPGS , Indian

Point Nuclear Generating Station, and the RosetOn Generating Station, as a means of reducing

plant operational impacts on ichthyoplanktOn through entrainment. Reduction in water

withdrawal can be accomplished through either reducing cooling water pump flow rates, or

through unit outages. In order to meet the requirements of the Settlement Agreement related

to reduction in cooling water withdrawal BPGS relies primarily on unit outages, with some flow

reduction.

The location of the BPGS cooling water intake structure on Bowline Pond offers a unique

setting for a riverine/esturaine intake , one which allows for the successful deployment of a

physical barrier. The cooling water intake structure is located along the shoreline of the 56 acre

Bowline Pond which is open to the tidal Haverstraw Bay section of the Hudson River through

a short channel about 6Om (200 ft) wide and 5m (16 ft) deep at mean low water. The shallow

pond inlet limits pond access to Hudson River resident and migratOry biological populations,

while the expanse of the pond minimizes intake water velocities. The use of a physical barrier

at BPGS is the preferred mitigative strategy since: the location of the intake on Bowline Pond

offers a low velocity zone from which to withdraw cooling water, following initial material

Lawler, Matusky & Skelly Engineers
costs, pyhsical barriers have been shown to be an economical mitigation strategy, and no

behavioral barrier device or system evaluated on the Hudson River has demonstrated

effectiveness at limiting cooling water withdrawl impacts on fish let alone on poorer swimming

ichthyoplankton.

In order to permit greater versatility in plant operation through the elimination of required unit

outages ORU contracted Lawler, Matusky and Skelly Engineers (LMS) to determine the

feasibility of deploying a fine mesh barrier net at the Bowline Pond intake to the Bowline Point

Generating Station during the spring-summer months as a means of reducing ichthyoplanlcton

entrainment. The initial phase (Phase I) of the feasibility study was conducted during the

summer of 1992 and included: (1) summarizing ichthyoplankton information from the Hudson

River (Haverstraw Bay), and Bowline Pond (including entrainment), (2) obtaining information

on water velocities in Bowline Pond concentrating on the inlet to the Pond and the current

barrier net deployment area, and (3) monitoring mesh test panels for biofouling potential and

loss of filtration efficiency due to clogging and biofouling. In general , the results of the initial

study phase indicated that a fine mesh barrier net could potentially be deployed at the cooling

water intake during the spring-summer months; however, there were several areas of concern

related to barrier net deployment (LMS 992a). The primary areas of concern were related to

net stress caused by reduced filtration efficiency due to clogging and biofouling, continual net

integrity due to damage from floating and submerged debris, and interference with plant

operation due to intake blockage.

2 PROGRAM OBJECTIVES

Taking into consideration the results of the Phase I study, the primary program objectives for

Phase II of the fine mesh barrier net evaluation study were: design and deployment of a fine

mesh barrier net, monitoring the net during the deployment period for clogging and biofouling,

and determining the effectiveness of the net at limiting ichthyoplankton access to the BPGS

cooling water intake. Specific program objectives are listed below:

I. Select target species for barrier net exclusion, and determine mesh size and

period of deployment to maximize effectiveness of the fine mesh barrier net.

Lawler, Matusky & Skelly Engineers
2. Determine the best method for barrier net deployment - one that maximizes net

area while offering an easy method for cleaning and/or removal.

3. Track net clogging and biofouling during the period of deployment with the

intent of using the information in designing a full time spring/summer fine mesh

barrier net system.

Lawler, Matusky & Skelly Engineers
CHAPTER 3

SITE DESCRIPTION

BOWLINE POND

The cooling water intake for the Bowline Point Generating Station (BPGS) is located on

Bowline Pond, a small embayment on the west shore of the Hudson River 60 kilometers (km)

(37 miles) north of the Battery (Figure 3- 1). Bowline Pond is connected to Haverstraw Bay,

a wide shallow area of the lower Hudson River, formed on the north by Stony Point and on the

south by Croton Point. Hudson River water enters Bowline Pond through a dredged inlet that

is approximately 5.0 meters (m) (16.5 feetrft)) deep at mean low water, and has a surface and

bottom width of 67 and 37 m (219 and 120 ft), respectively. The calculated open area of the

inlet at mean low water is 260 m2 (2797 ft2). Bowline Pond is irregular in shape with several

small coves and has a surface area of 0.23 km2 (56 acres) (Figure 3-2). The maximum depth

in the Pond is approximately 12 m (40 ft); Pond depth in the immediate vicinity of the BPGS

intake building, located on the west shore of the Pond, is 9 m (30 ft). The shallow shore zone

around the Pond supports a dense growth of aquatic plants during periods of warmer water

(LMS 1981 , Matousek et at. 1981).

Velocity profiles were conducted at the inlet to Bowline Pond and at various locations in the

Pond covering an entire tidal cycle during 10 September 1992. During the water velocity

survey period, BPGS was operating two circulating water pumps (CWP) resulting in a total

plant withdrawal from Bowline Pond of2392 cubic meters per minute (m /min) (1408 cubic feet

per second rcfs)). Water velocity values recorded at the inlet to the Pond and in the vicinity

of the deployed 9.5 millimeter (mm) (0.38 in.) barrier net are presented in Table 3- 1. Bowline

Pond inlet water velocity during the low slack tidal condition, corresponding to the lowest water

depth, averaged 32. 7 centimeters per second (cm/s) (1.08 feet per second (fps)). Average water

velocities recorded during maximum flood, high slack, and maximum ebb were similar

averaging 19. 1 cm/s (0.63 fps), ranging from 18, 9 to 19. 5 cm/s (0,62 to 0.64 fps). Average

water velocity values in the vicinity of the BPGS cooling water intake structure (area of barrier

Lawler, Matusky & Skelly Engineers
BOWLINE POINT STATION

RM37

TROY DAM

ALBANY

RENSSELAER

SAUGERTIES

... HAVERSTRAW

'h:'€",

,IV.:f~?-\'

Atlantic Ocean

FIGURE 3-1

LOCATION OF

BOWLINE POINT

GENERATING STATION

SAR,NET,

ORANGE & ROCKLAND UTILITIES, INC.

FINE MESH BARRIER NET STUDY

LAWLER, MA TUSKY & SKELL Y ENGINEERS

Pearl River, New York
Source: EA (1989).

BOWLINE

POND

HUDSON

RIVER

DIFFUSER

RIVER

SHORELINE

INTAKE

CHANNEL

60 120 m LJ 

SCALE IN METERS

FIGURE 3-2

GENERAL PLAN VIEW OF THE

CIRCULATING WATER SYSTEM

BAA-NET,

ORANGE & ROCKLAND UTILITIES, INC.

FINE MESH BARRIER NET STUDY

LAWLER, MATUSKY & SKELLY ENGINEERS

Pearl River, New York
Table 3-

WATER VELOCITY SURVEY

BOWLINE POND: 10 September 1992

Bowline Pond Inlet

Water Water Velocity (feet per second)

Tidal Condition Time Depth North Center South Averaae

Low Slack 0645-0656 Surface 689 013 135 946

Mid-depth 182 338 760

Bottom 520 520 676 239

,Average 605 238 383 075

Maximum Flood 1002-1013 Surface 845 507 169 507

Mid-depth 845 676 507 676

Bottom 845 845 338 676

Average 845 676 338 620

High Slack 1210- 1235 Surface 676 676 676 676

Mid-depth 507 845 676 676

Bottom 338 507 845 563

Average 507 676 732 638

Maximum Ebb 1613-1623 Surface 355 845 507 569

Mid-depth 676 676 676 676

Bottom 507 507 845 620

Average 513 676 676 622

owline P .Oint Generatina Station: Barrier Net Deployment Transect

Water Water Velocity (feet per second)

Tidal Condition Time Depth North Apex South A veraae

Low Slack 0715-0750 Surface 220 135 338 231

Mid-depth 338 338 338 338

Bottom 0.423 338 507 0.423

Average 327 270 394 330

Maximum Flood 1040-1115 Surface 169 135 110 138

Mid-depth 287 169 338 265

Bottom 135 287 220 214

Average 197 197 223 206

High Slack 1300-1330 Surface 220 169 093 161

Mid-depth 169 338 169 225

Bottom 254 338 423 338

Average 214 282 228 241

Maximum Ebb 1640-1710 Surface 169 169 152 163

Mid-depth 254 507 237 333

Bottom 254 676 237 389

Average 226 0.451 209 295

3-1A
net deployment) (Table 3- 1) ranged from 10. 1 cm/s (0.33 ips) recorded at low slack to 6.4 cm/s

(0.21 ips) recorded at maximum flood. In general the higher water velocity values were

recorded at the bottom and the lowest values at the surface, however, the difference between

water strata was not substantial. The tidally averaged water velocity was 8.2 cm/s (0.27 ips).

Bottom sediment core samples were collected from the vicinity of the intake structure on 26

April 1993. Core logs are presented in Attachment 1. In general , Bowline Pond sediments

consist of a layer of gray-black organic silt approximately 0.3 to 1.2 m (1 to 4 ft) thick

overlaying gray clay. Core depths ranged from 2.6 m (8.6 ft) to 4. 1 m (13.3 ft), with no

evidence of bedrock or solid material noted at the depths evaluated. Core samples taken in

Bowline Pond near the existing intake structure during plant construction, indicate that stiff

varied clay exists to a depth of approximately 15 m (50 ft). Below the clay layer is a dense to

very dense layer of glacial till approximately 6 m (20 ft) thick which overlays bedrock

comprised of sandstone, shale , and siltstone (Bechtel 1970).

2 BOWLINE POINT GENERATING STATION

The Bowline Point Generating Station (BPGS) consists of two fossil-fuel fired , steam electric

units, each having a net generating capacity rating of 600 MWe and a gross capacity of 622

MWe. Condenser cooling water for each unit is pumped from an intake structure located on

Bowline Pond, and after passing through the condenser tubes is discharged on the western side

of Haverstraw Bay through a submerged diffuser system located in approximately 4.5 m (15 ft)

of water.

Each generating unit has three circulating water pumps (CWP) each with a rated capacity of 485

/min (128,000 gallons per minute (gmpD. Different pump combinations are used for use

operating unit, including throttling ofthe condenser discharge butterfly valves to a 60% position

(NAI 1992). In general, under maximum unit generation and peak seasonal water temperatures

(summer conditions) only two CWPs (unthrottled) are in operation. Generating unit cooling

water flow rates related to the varying CWP operating conditions are presented in the following

table:

Lawler, Matusky & Skelly Engineers
CIRCULATING

WATER PUMPS IN

OPERATIONS

COOLING-WATER FLOW RATE PER UNIT

FLOW PER MINUTE CUBIC FLOW PER DAY

MILLION

METERS GALLONS CUBIC (gal) METERS

MILLION

GALLONS

2 (throttled)

700

973

1196

1454

185,000

257 000

316 000

384 000

1.01

1.40

1.72

266

370

455

553

Operating characteristics for BPGS is presented in Table 3-

The BPGS has a separate once-through cooling water system for each unit. The cooling water

intake building is a reinforced-(;oncrete structure measuring 42.7 m (140 ft) across its face and

21.3 m (70 ft) on each end (Figure 3-3). Water depth at the intake face is approximately 9.

m (30 ft) at mlw. There are six openings or ponals on the face of the intake structure and one

on each end. Each opening measures 4.9 m (16 ft) wide and 7.9 m (26 ft) high. The two side

openings or lateral fish passageways were incorporated into the intake structure to eliminate

dead spaces associated with screen channels that could trap fish. Each of the eight intake

openings is fitted with a venically oriented trash rack having clear spacing between bars of 9.

em (3.5 in. ). The six intake traveling screens are conventional venical traveling band screens

capable of operating at two speeds , 1. 8 and 3.7 m/min (6.0 - 12. 0 ftlmin), and having separate

low and high pressure spray washes. Under normal operation the intake traveling screens are

operated continuously. Fish and debris are washed from the front of the screens by an internal

spray header, collected in a water-filled sluicev.:ay, and returned to the Pond approximately 30

m (95 ft) from the north side of the intake structure (outside the barrier net when deployed) via

an 45. 7 em (18 in.) diameter fiberglass pipe. The screen mesh is constructed of stainless steel

with 9.5 mm (0.375 in.) square openings. A plenum extending from the bar screens through

the middle of the intake house separates the traveling screens and CWPs for the two generating

units .

Lawler, Matusky & Skelly Engineers
TABLE 3-

OPERATING CHARACTERISTICS OF BOWLINE POINT

GENERATING STATION

CHARACTERISTICS UNITS 1 AND 2 (EACH)

OPERATING

Nominal generating capacity (MWe)

Cooling-water flow rate (m /min)

Condenser

Service water'

Heat rejeetion rate (Btu/hr)

Cooling-water temperature rise (D

600

1,422

8 x 109

INTAKE

Type of intake

Maximum approach velocity to the screens (em/see)

Pipe diameter from intake to condenser (m)

Total flow (m /min)

Shoreline

23.

1,454

THERMAL DISCHARGE

Length of subaqueous discharge pipe from existing Hudson River

shoreline (m)

Pipe velocity (em/see)

Length of diffuser (m)

Number of diffuser ports

Inside diameters of diffuser ports (m)

Port spacing (m)

Initial jet velocity (m/see)

Total diffuser flow (m /min)

A verage depth to port centerline below mean low water (m)

A verage depth to river bottom below mean low water (m)

Port temperature rise above river ambient (D

370

300

67.

454

6.4

Service water drawn from main circulating water flow.

Source: ORU (1977).
BOWLINE POND

K 42.7 m 

SHEET PILING BULKHEAD

10 m h--L--J

SCALE

1 in. = 10m

BAR,NET,

BOWLINE POINT GENERATING STATION

INTAKE STRUCTURE 21.3 m

FIGURE 3-3

PLAN VIEW OF

INTAKE STRUCTURE

ORANGE & ROCKLAND UTILITIES, INC.

FINE MESH BARRIER NET STUDY

LAWLER, MATUSKY & SKELLY ENGINEERS

Environmental Science & Engineering Consultants
CHAPTER 4

DESCRIPTION OF FINE MESH BARRIER NET

1 MESH SELECTION

Selection of Target Species

The first step in the evaluation of a fine mesh barrier net for deployment at BPGS was to select

the target ichthyoplankton population, Le. , the population that would be used to determine the

effectiveness of the barrier net. Under Phase I of the fine mesh barrier net evaluation study,

LMS prepared a report detailing the available information on ichthyoplankton populations in

Haverstraw Bay and Bowline Pond (LMS 1992). Overall several fish species were represented

in ichthyoplankton collections from the Hudson River in the vicinity of BPGS. The dominant

species of fish occurring as ichthyoplankton in the area were; bay anchovy (Anchoa mitchilll),

striped bass (Morone saxitilis) , white perch (Morone americana) , American shad (Alosa

sapidissima), alewife (Alosa pseudoharengus), and blueback herring (Alosa aestivalis). Other

species common to the area, but noted in substantially lower numbers were; American eel

(Anguilla rostrata) , hogchoker (Trinectes maculatus) , bluefish (Pomotomus saltatrix) , and

rainbow smelt (Osmerus morck1x).

Overall the dominant species collected in both plant entrainment, and river sampling programs

in this river region, was the bay anchovy comprising greater than 80% of the specimens

collected. Bay anchovy larvae are present in the BPGS vicinity in relatively high densities from

late June through August, with a late July-early August peak. Greater than 90% of the bay

anchovy collected are post yolk-sac, with the period of peak abundance extending from mid-July

through the end of August (LMS 1992b). The average length range reported for bay anchovy

post yolk-sac larvae is 2.7 to 16. 0 mm, with the mean length recorded during the period of peak

abundance ranging from 13.0 to 15. 5 mm.

Lawler, Matusky & Skelly Engineers
The bay anchovy was selected as the target species for the determination of the effectiveness

of the Bowline Point fine mesh barrier net at minimizing ichthyoplankton entrainment.

2 Mesh Size Selection

Aquatic organism retention on a porous surface (impingement), the organism s ability to pass

through a mesh opening (entrainment), or the ability of the organism to avoid the porous surface

(exclusion) are functions of the size of the mesh opening, the size and developmental stage of

the organism, and hydraulic conditions. Physical exclusion by a porous surface (screen, net)

occurs when the mesh size is smaller than the organism susceptible to entrainment;

hydrodynamic exclusion results from a low through-slot velocity, which limits extrusion of the

organism through the mesh. In addition, sensory and swimming capabilities of the organism

i.e., ability of the organism to perceive the porous surface and swim against the local currents,

contributes to the exclusion potential of the screen system.

Several investigators have evaluated the properties of screening system mesh size opening

related to the entrainment and impingement of fish larvae. Browne et al. (1981) evaluated

entrainment through a cylindrical wedge-wire screen, and found no significant difference in

entrainment through 1.0 and 2.0 mm mesh screens. Weisberg et al. (1984) evaluated mesh

exclusion and entrainment through cylindrical screens with wedge-wire mesh openings of 1.

0, and 3.0 mm, and found the greatest exclusion by the smaller mesh; however, overall there

was no significant difference in entrainment among the mesh sizes tested. The exclusion

potential of the various size meshes increased at a disproportionately greater rate with an

increase in the size of the fish larvae tested. An evaluation of fish larvae entrainment through

cylindrical screens with 2.0 and 9.5 mm mesh found lower entrainment through the 2.0 mm

mesh; however, the principal finding of the study was that for cylindrical screens equipped with

wedge-wire mesh, entrainment reduction of fish larvae is substantially better for larger mesh

sizes than can be accounted for by physical exclusion alone (Zeitoun et al. 1981).

Schneeberger and Jude (1981), in a study designed to predict the exclusion capabilities of smallmesh screens on Great Lakes fish larvae, concluded that fish larvae body dimensions (maximum

Lawler, Matusky & Skelly Engineers
depth, average cross-sectional area) in relation to screen mesh size was the primary determinant

of screen efficiency. They determined that body depth exceeded body width, and that to predict

potential entrainment or impingement, the cross-sectional dimensions were best compared to

total body length. Several other studies designed to evaluate the effects of screen mesh size on

fish larvae entrainment and screen retention, have concluded that body depth is the more

accurate morphometric measurement related to screen retention and entrainment (Tomljanovich

et a1. 1977, 1978; EAI 1981; Edwards et a1. 1981; Taft et a1. 1981; Fletcher 1990).

However, the same studies that have determined that body depth is the most important factor

related to mesh selection have found that mesh retention (or exclusion potential) is not solely

dependent on body depth - other factors that influence mesh exclusion potential include;

velocity, shape of the mesh opening, percent open area, visibility, clogging and biofouling, and

sensory and swimming capabilities of the target species.

Body depth to total body length relationships were developed for larvae of several species of

fish (Schneeberger and Jude 1981), with one of the species, the spottail shiner (Notropis

hudsonius), a minnow species with a body shape similar to the bay anchovy. To establish a

baseline for the selection of the fine mesh barrier net mesh size, the formula developed for the

spottail shiner was used to estimate the body depth of post yolk-sac bay anchovy, representative

of the peak abundance period. A body depth of approximately 1.9 mm was estimated for a

larvae 13.0 mm in total length, and a body depth of 2.4 mm was estimated for a larvae with

a body length of 15. 5 mm. The bay anchovy post yolk-sac larvae body depth estimates indicate

that the minimum mesh size should be 2.0 mm.

Based on the results of morphometric analysis, the size of the mesh opening in a barrier net

designed to exclude post yolk-sac bay anchovy at BPGS should be approximately 2.0 to 2.

mm. Given the clqgging potential of the smaller mesh openings, the greater availability of

manufactured net material with mesh openings in the 3.0 to 6.0 mm size range, and since it has

been demonstrated that hydraulic and biological considerations contribute to the exclusion

potential of a screen system, the mesh size selected for use in the BPGS fine mesh barrier net

evaluation study was 3.0 mm (0. 125 in). Initial contacts with net suppliers indicated that the

0 mm mesh was available with multi-faceted (delta mesh) opening design. The non-square

Lawler, Matusky & Skelly Engineers
opening design is preferred to the square or bar design as it minimizes the diagonal or stretch

dimension which could permit the passage of a larvae with a deeper body depth dimension.

Following the selection of the 3.0 mm size mesh, net manufacturing companies were contacted

to obtain net samples which could be used to determine percent open area. Several samples 

woven nylon netting with multi..faceted 3.0 mm mesh openings were received. Woven mesh

was obtained in two different mesh opening styles: Ace, which is oval in shape, and Delta

which is hexagonal in shape. The twine break test for the Ace mesh netting was 24 lb, and the

Delta twine break test was 35 lb. In addition, the net samples were supplied treated (dipped

in plastic) and untreated. Measurements were made on both net styles - treated and untreated -

and the percent open area for each net sample was determined using the formula:

Percent Open Area (I-ND) (1-nd) x 100

where:

N = Horizontal threads per inch

n = Vertical threads per inch

D = Diameter of horizontal twine

d = Diameter of vertical twine

The calculated percent open area for the nylon net samples were:

24 lb Ace (untreated) = 42.9 %

24 lb Ace (treated) . = 42.2 %

35 lb Delta (untreated) = 53.6 %

35 lb Delta (treated) = 51.9 %

The 35 lb Delta untreated material was selected for the BPGS fine mesh barrier net.

4-4

Lawler, Matusky & Skelly Engineers
NET DESIGN

After selecting the target species and the appropriate size of the net mesh opening, the next step

was to design the barrier net - configuration, and method of deployment and removal. Several

factors were considered in designing the fine mesh barrier net:

1. Maximize net surface area to maintain through mesh velocity at or below 

cm/s (0.5 fps).

2. For increased net strength and durability (ability to withstand the influence of

large debris), the net would be constructed as a two layer system; the fine mesh

(3.0 mm) larval exclusion net supported by a second net with larger mesh

openings and constructed of stronger nylon twine.

3. Construction of the net in sections or panels to facilitate handling during

deployment, cleaning, and retrieval.

4. Consider the use of pilings for added net support, and possibly permit easier net

deployment and retrieval.

5. Potential use of a plastic net material that would be more resistant to biofouling

as determined from panel observations conducted during 1992.

6. Utilize existing barrier net deployment techniques and equipment as much as

possible.

To determine the minimum net surface area required to result in the desired through net velocity

of 15 cm/s (0.5 fps) or less, the maximum BPGS cooling water flow projected for the study

period of 32.3 m /s (512 116 gpm; 1141 cfs) (four circulating water pumps, unthrottIed) was

used, with all of the flow assumed passing through a barrier net with 50% open area. The

minimum net surface area was determined to be 424 m2 (4564 ft2

Discussions with net manufacturers resulted in the selection of a backing net constructed 

Number 21 twisted nylon twine with a square mesh opening of 4.45 cm (1.75 in). Number 21

twisted nylon twine is approximately 1.65 mm (0.065 in) in diameter with a break test rating

of 90. 7 kgs (200 lbs). The large mesh opening of the support net was considered to have

minimal influence on the filtration capacity of the fine mesh net.

Lawler, Matusky & Skelly Engineers
The initial length of the net sections was set at 15.2 m (50 ft), panel lengths were increased by

6 m (15 ft) to accommodate deployment between pilings (see Section 4.3) installed

approximately 15 m apart. Net panels in this size range would be easy to handle, and would

be easy to customize to meet the varied depth contours in the vicinity of the cooling water

intake structure. In addition , the net manufacturer indicated that it would be easier to match

the drape of the fine mesh and large mesh net material in relatively small sections. Each net

section would be constructed using 9.5 mm (0.375 in.) diameter braided polypropylene rope.

In addition, a second rope was attached 30 cm (1 ft) above the bottom line to assist in

maintaining the bottom seal (Figure 4-4). Floats with a buoyancy rating of 850 grams (30

, ounces) were attached every 30 cm (12 in) along the top line of each net section.

Water passage through the fine mesh barrier net would result in substantial stress on the net

deployment lines, and anchors. The 9.5 mm mesh barrier net (NAI 1993) is deployed from a

buoyed surface line using anchors at the mid-point of the north and south wings to maintain its

position. Given the increased stress associated with the fine mesh net, the use of anchors was

not considered practicable. The alternate deployment technique relied on the installation and

use of wooden pilings. The sediment sampling conducted in Bowline Pond during 26 April

1993 , indicated an organic sediment layer ranging from one to two meters thick overlaying a

dense gray clay. Core samples were not conducted to a depth that permitted the determination

of bedrock or competent hard sediment. Utilizing the results of the April core samples and

sediment information developed during plant construction, it was concluded that wooden pilings

with a 35. 6 cm (14 in.) butt and 22.9 cm (9 in.) tip driven into the sediment approximately 6

m (20 ft) would support the fine mesh barrier net (ORU 1993).

The Phase I work conducted in Bowline Pond during the summer of 1992, included the

biofouling potential of several types of mesh materials. Overall, the material that exhibited the

lowest rate of biofouling, and also was observed to clean the easiest, was a 3.0 mm mesh

constructed of polyethylene. Manufacturers of polyethylene netting were contacted related to

supplying material for the fine mesh barrier net, however, no manufacturer had the small mesh

material available in sizes which could economically be used to construct the required panels.

4-6

Lawler, Matusky & Skelly Engineers
Since polyethylene netting material was not available, the experimental fine mesh barrier net

was constructed of nylon material.

3 BARRIER NET DEPLOYMENT

Several Bowline Pond areas were considered for deployment of the fine mesh barrier net, with

the greatest emphasis concentrated on the inlet to the Pond, and the area currently used to

deploy the 9.5 mm mesh barrier net. Following a detailed evaluation of all possible net

deployment locations, the area immediately in front of the intake stucture, the same area where

the 9. 5 mm mesh barrier net is currently deployed, was selected. Reasons why the other

deployment locations were eliminated related to limiting public access to Bowline Point (public

access is currently unrestricted), time and costs associated with obtaining permits, economic

considerations related to net size, and restrictions imposed on ORU personnel related to the use

of the Bowline Pond oil boom boat docking facilities.

Items considered for the deployment of the fine mesh barrier net around the Bowline Point

cooling water intake structure were:

1. Deployment of the net in a "V" pattern with the apex of the net 45.7 m (150 ft)

from the centerline of the face of the intake structure.

2. Use the existing bulkhead attachment points located approximately 35 m (115 ft)

north and 40 m (130 ft) south of the cooling water intake structure.

3. Deploy the net to maximize the distances between the intake structure and the

net. The minimum distance was estimated at approximately 22.5 m (75 ft).

4. Optimize net surface area through the use of additional angled net sections. The

additional sections would also help in changing clogged net sections.

The basic configuration for the deployment of the fine mesh barrier net, considering the items

listed above, is presented in Figure 4- I. The use of additional angled net sections was

abandoned following receipt of barrier net section cost estimates, and the cost for installing four

additional pilings needed for deployment of the angled sections. However, angled net sections

Lawler, Matusky & Skelly Engineers
...

ORU

BOAT DOCK

SEMIPERMANENT NET SECTIONS

/ \ .:. 

:

., 

c::- CHANGEABLE NET SECTIONS

\

...... 

I ......

/

\ 

...... \ ...... ......

\ 

. ....... 

...... ...... ...... ...... , 

...... ...... 

\ 

ANGLED NET SECTION

BOWLINE POINT

SCREENHOUSE

PILING

50 ft

!

SCALE

1 em = 50 ft

FIGURE 4-1

BOWLINE POINT

PRELIMINARY DESIGN PLAN VIEW

FINE MESH BARRIER NET

BAA,HET,

ORANGE & ROCKLAND UTILITIES, INC.

FINE MESH BARRIER NET STUDY

LAWLER, MATUSKY & SKELLY ENGINEERS

Environmental Science & Engineering Consultants
may be revisited if a permanent net installation is proposed following the completion of all

experimental work.

Bottom profiles were obtained from the area of the BPGS cooling water intake structure during

7 April 1993 (Attachment 2). From the bottom profiles a detailed bottom contour layout related

to the tidally varying water depth in Bowline Pond was constructed (Figure 4-2). The depth

profiles permitted the calculation of average and minimum water depths in the immediate

vicinity of the BPGS cooling water intake structure which were used to calculate net panel

dimensions.

Nine wooden pilings were driven to a minimum depth of six meters (20 ft) in a '

configuration around the Bowline Point cooling water intake structure during 7 and 8 July 1993.

Two criteria were established for pilings installation; I) apex piling would be 45.7 m (150 ft)

from the center of the face of the intake structure, and 2) the distance between pilings would

be 15. 2 m (50 ft). The piling installation configuration including actual dimensions referenced

to the BPGS cooling water intake structure is presented in Figure 4-3. The distance between

pilings was maintained at 15.2 m (50 ft), with the resulting distance from the pilings closest to

the bulkhead on the north (piling Nl) and south (piling Sl) side , 12.3 m (40.6 ft) and 20.6 m

(68.0 ft) respectively.

The length of each barrier net panel was designed to be 4.6 m (15 ft) longer than the distance

between attachment points (pilings, bulkhead). Based on the depth profile information, the

depth for the panels to be deployed between pilings N2 around the apex to piling S2 was 11.

m (36 ft), panels for deployment between pilings NI-N2 and SI-S2 was 9.8 m (32 ft), and the

two end panels were tapered from 6.7 m (22 ft) at piling Nl and 7.9 m (26 ft) at piling SI to

5.5 m (18 ft) at the bulkhead. Floats were attached every 30. 5 cm (12 in) along the surface line

of each net section.

Following installation of the wooden pilings, 9.5 mm galvanized steel cable was stretched

between the pilings at the bottom (installed by divers on 19 July 1993), and approximately one

Lawler, Matusky & Skelly Engineers
10.., 1211

i!= 15

ffi 20

3: 25

i!= 15ffi 20

c:(

3: 25

BULKHEAD

... ..........,........... .. ...........

r,.."

N,~ 28:511

29.FII

122 140 172 190

125 150 175

26, 511

100

,.....,.......,...

,0.,..................., .............,.....,..,.

...........,... ...,..,....,....,.......,.,....

,........,

,0,..,

BAR.NET,

140

150

122

125 100

DISTANCE FROM BULKHEAD TO APEX (ft)

... j.,. .,....,.,........,...

28;511

172

175

200

...................,....... ,........,...,....,

222

225

I Northern Section Profile I

...

1511

~EX

240

250

....,............,...

,..,.. ;.........,..

....... ,......

Southern Section Profile I

...

190

200

29, 511

222

225

2~. 511

~EX

240

250 275 300

FIGURE 4-2

BOTTOM PROFILE

ALONG FINE MESH BARRIER NET

DEPLOYMENT TRANSECTORANGE & ROCKLAND UTILITIES, INC.

FINE MESH BARRIER NET STUDY

LAWLER, MATUSKY & SKELLY ENGINEERS

Environmental Science & Engineering Consultants
50 ft h -

\

SCALE

1 em = 50 ft

BA.,NET.

S-4

15,1 m 1 5-3

PILING

15. 5-1

BOWLINE POINT

SCREEN HOUSE

FIGURE 4-3

BOWLINE POINT

FINE MESH BARRIER NET

PILING INSTALLATION

DESIGNATION AND MEASURED

DIST ANCES

ORANGE & ROCKLAND UTILITIES, INC.

FINE MESH BARRIER NET STUDY

LAWLER, MATUSKY & SKELLY ENGINEERS

Environmental Science & Engineering Consultants
meter above the waters surface referenced to high tide. In addition, two 25.4 cm (10 in) cleats

were attached, one on each side, near the tOp of each piling.

Fine mesh barrier net deployment consisted of the following steps:

I. Net panels were sewn together in a sequence related to deployment from the

south bulkhead to the north bulkhead. Two chains were attached to the bottom

of each panel; one chain was attached at the very bottom of the net panel and the

second was attached one meter (3 ft) up from the bottom.

2. The complete net was loaded on the barrier net work platform , and the net

attached to the south bulkhead using a cable running through the existing eyebolts. Bulkhead attachment was performed by a diver.

3. Barrier net was payed out from the work platform and attached to the first piling

(S I). The bottom of the net was attached to the bottom of the piling by a diver

using a rope. Shackles were attached to the steel cable which was secured

around the bottom of the piling, and the net rope was brought to the surface and

tied off at one of the cleats after passing through the shackle. Two lines (one

from the corner of each panel) were used to secure the bottom of the net at each

piling.

4. Additional lines , one every 3 m (10 ft), were attached to the bottOm of the net

passed under the bottom support cable, brought to the surface, and secured to the

top support cable.

5. Additional lines , one every 3 m (10 ft), were attached to the float line of the net

and secured to the top support cable.

The deployment procedure described above was repeated at each piling and at the north

bulkhead attachment. A schematic diagram of the deployed net is presented in Figure 4-4.

Over the course of the evaluation study period, net clogging problems related to large numbers

of immature jellyfish, fine silt, and filamentous algae caused the net to sink. On several

occassions water was observed spilling over the tOp of clogged net sections , which could result

in surface oriented larvae entering the protected intake area. In general , the problem of net

sinking was rectified within 12 hours through the attachment of additional floatation to the

surface float line. Ultimately, cleaning of the net was required to restOre adequate net filtration

to maintain the top of the net at the water s surface.

Lawler, Matusky & Skelly Engineers
150ft

147ft

8O'M..INE POINT

SCREENHOUSE

PLAN VIEW

... ... ... .... ...

NET SECTION

/ 

.r-

/ 

FIGURE 4-4

Chain FINE MESH BARRIER NET

DEPLOYMENT

BAR....-r.

SIDE VIEW

ORANGE & ROCKLAND UTILITIES, INC.

FINE MESH BARRIER NET STUDY

LAWLER, MATUSKY & SKELLY ENGINEERS

Pearl River, New York
CHAPTER 5

EVALUATION PROGRAM DESCRIPTION AND RESULTS

1 EVALUATION PROGRAM DESCRIPTION

1.1 Water Velocity Profiles

To assist in evaluating the filtration efficiency and biofouling potential of the fine mesh barrier

net, 'velocity measurements were periodically recorded at points inside the deployed net. Depth

profile velocity measurements were normally recorded at two locations along the north side and

tWo locations along the south side. The points selected for monitoring water velocity were; (1)

between pilings NI and N2, (2) between pilings N3 and N4, (3) between pilings 53 and 54, and

(4) betWeen pilings 51 and 52 (Figure 4-3). Water velocities were recorded at one meter

intervals from one meter below the waters surface to bottom using a Marsh McBirney Model

2000 velocity meter. In addition, velocity profiles were scheduled to be conducted at the center

of each intake with operating cooling water pumps, however, heavy debris loading on the trash

racks following removal of the 9.5 mm mesh barrier net, precluded monitoring intake water

velocity. Background velocity profiles were conducted at two locations along the north side and

one location along the south side following piling installation and prior to net deployment (20

July 1993).

1.2 Clogging and Biofouling

Net Mesh Observations. Prior to ordering the 3.0 mm mesh barrier net, 1.0 m2 panels

of treated and untreated, 24 lb. Ace and 35 lb. Delta nylon mesh netting were suspended in

front of the Bowline Point cooling water intake structure to evaluate clogging and biofouling

potential. Water depth at the face of the intake structure is approximately 9 meters (30 it) at

mean low water, with the depth of the test panels set approximately 3 meters (10 it) above the

bottom. Percent open area was calculated for each test panel:

24 lb. Ace untreated = 42.

35 lb. Delta untreated = 53.

24 lb. Ace untreated = 42.

35 lb. Delta treated = 51.9%

Lawler, Matusky & Skelly Engineers
Two TSK velocity meters were mounted on each frame supporting a mesh panel , one meter on

the side of the frame and the second in the center of the frame upstream of the net. Panels

were visually inspected daily or every Other day for the first two weeks of deployment and then

periodically through the middle of June for debris buildup, biofouling, or sediment entrapment.

Differences in velocity meter readings between inside and outside meters were used to obtain

information on filtration efficiency. The four test frames were deployed on 26 April 1993, with

observations on biofouling and clogging extending until 15 June 1993. The test frames were

removed from the intake on 15 June 1993.

Test Panel Observations. On 23 July 1993 test panels constructed of the 3.0 mm mesh

barrier net material , with each panel measuring approximately 0.6 m square, were deployed

at 0.6 m below the waters surface, mid-depth and 1.0 m above the bottom at four locations

along the barrier net. Test panels were suspended from the top net support cable outside of the

barrier net. Test panels were removed for observation and photographed on 3 and 17 August

1993. Test panels were removed at the same time the fine mesh barrier net was removed on

23-24 August, observations on clogging and biofouling were noted at the time of removal.

1.2. Diver Observations. Divers were employed during 4-6 August 1993 to clean the

barrier net using an underwater hydrolaser (high pressure water spray). In addition, divers

were used on 20-21 August to remove the barrier net. During the net cleaning and net removal

operations, divers reported on the condition of the net, i.e., holes, debris buildup, deployment

configuration, water currents, biofouling, and classification/characteristic of clogging material.

Ichthyoplankton Monitoring

The primary focus of the Phase II study was the determination of barrier net effectiveness at

limiting the movement of bay anchovy larvae in the immediate vicinity of the Bowline Point

cooling water intake structure. To determine barrier net effectiveness, a direct comparison was

made between biological samples collected at locations outside of the barrier net to samples

collected at inside net locations.

Lawler, Matusky & Skelly Engineers
Four-inch trash pumps (Homelite Model No. 160TP4- 1) were used to collect entrainment

samples at the face of the intake structure in front of units with operating circulating water

pumps (CWP). One pump was set up on the cooling water intake structure walkway, with the

intake hose deployed at the center set of trash racks for Unit No. I , and a second pump was

set up at Unit No. 2. Sample water was withdrawn from three separate depths corresponding

to the top, middle and near bottom of the trash rack opening, and combined by discharging the

entire pump flow into a water buffered plankton net with 0.5 mm mesh (Figure 5- 1). The

sampling pump operation was adjusted to pump at a rate of approximately 1.1 m /min (300

gpm), with a sample duration of 30-min resulting in a total sample volume of 34 m3 (9,000

gals). Equal volumes of water were withdrawn by pumping for ten minutes from the three

designated water depths. Pumping rate was established at the beginning of each sample period

by adjusting the throttle on the gas operated pumps to achieve a specified time to pump a 1cnown

volume. A total of three pump samples were scheduled to be collected in front of each

operating Unit during a diurnal period on alternate days starting with the day prior to the

completion of net installation. The collection of the three diurnal pump samples was equally

spaced over the diurnal sampling period.

Plankton net tows were conducted inside the barrier net during each sample day. The inside

barrier net plankton net samples were a composite of two 0.5 m mouth diameter (0.5 mm mesh)

plankton net samples: one net deployed to sample the upper half of the water column (net depth

0 m), and the second net deployed to sample the lower half of the water column (net

depth 3. 5.5 m). A General Oceanics velocity meter mounted in the center of the plankton

net was used to determine the volume of water sampled for each tow. The two inside barrier

net plankton net tows were composited in the field following a visual inspection to note the

presence and general abundance of fish larvae and macroinvertebrates.

Plankton nets with a mouth diameter opening of 0.5 m and 0.5 mm mesh were used to collect

samples outside the barrier net. Two transects were sampled one along the north wing and the

second along the south wing of the net, with each transect extending from the bulkhead to the

apex of the net (Figure 5-2). Two plankton nets were towed along each transect; one with the

depth set at 1.5 to 2.0 m to sample the surface to mid-depth part of the water column, and the

Lawler, Matusky & Skelly Engineers
SCHEMATIC

VALVE 

COLLECTION NET

\\

FLEXIBLE HOSE 

. \ \ \\ \

STEEL END TO SUOE ALONG TRASH RACK 

...

WATER LEVEL

~OW

OPERATING VIEW

DISCHARGE HOSE

FILTERED WATER

DISCHARGE

GRATES

IN DECK

SAMPLE NET

IN WATER FILLED CONTAINER

I I

I I

I I

I I

WATER LEVEL

TRASH

RACKS

STEEL COLLECTION END

SLIDES ALONG TRASH RACK

INTAKE OPENING

FIGURE 5-1

DIAGRAM OF

ENTRAINMENT ABUNDANCE

SAMPLING SYSTEM

ORANGE & ROCKLAND UTILITIES, INC.

FINE MESH BARRIER NET STUDY

LAWLER, MATUSKY & SKELLY ENGINEERS

8AA'NET. Pearl River, New York
second with net depth set at 3.5 to 5.5 m to sample the mid-depth to bottom part of the water

column. The contents of each depth sample from each transect were composited in the field

following visual inspection to determine the presence and relative abundance of fish larvae and

macroinvertebrates. Nets were towed at 120 cm/s (3.9 fps), with velocity through the water

monitored using a General Oceanics velocity meter (Model No. 2031) with on-deck readout

(Model No. 2035). Transect tow times ranged between 60 and 75 seconds, with composite

sample volumes between 28 and 36 m3 (7400-9510 gal). All tows were initiated at the bulkhead

and were terminated at the apex of the net.

Water quality information including water temperature (oC), dissolved oxygen (mgll), specific

conductance ClLmhos/cm at 25OC), salinity (parts per thousand (pptD, and transparency (cm)

were recorded at the end of each outside net sample collection at a station near the apex of the

net on the south side. Water quality information was recorded using calibrated meters, with

values recorded at 0.3 m (1 ft) below the surface, mid-depth, and 0. 5 m (1.5 ft) above the

bottom. Water transparency was based on the visibility of a 22.9 cm Secchi d

Inside and outside plankton net samples and intake pump samples were collected on the same

diurnal schedule. In general , two to three collections were conducted during each diurnal

period. At the minimum, one set of net samples were collected during the morning hours, and

another set were collected during the afternoon.

Inside and outside barrier net samples were analyzed separately. All ichthyoplankton (larvae)

were identified to species, and counted. A representative sample of each identified species was

measured for total length. Body depth measurements were recorded for the dominant bay

anchovy over the course of the study period.

5-4

Lawler, Matusky & Skelly Engineers
OUTSIDE

NORTH SAMPLE

TRANSECT

OUTSIDESOUTH SAMPLE

TRANSECT

BOWLINE POINT

SCREENHOUSE

50 ft

SCALE

1 em = 50 ft

FIGURE 5-2

5m PLANKTON NET

SAMPLE TRANSECTS

ORANGE & ROCKLAND UTILITIES, INC.

FINE MESH BARRIER NET STUDY

LAWLER, MATUSKY & SKELLY ENGINEERS

Environmental Science & Engineering Consultants
PROGRAM RESULTS

1 Bowline Point Operation

Circulating water pump operation and cooling water withdrawal information covering the fine

mesh barrier net evaluation period is presented in Table 5-1. The fine mesh barrier net was

deployed between 21 July and 23 August - the period of barrier net deployment is designated

in Table 5-

In general, during the first six days and the final 17 days of barrier net deployment, two CWPs

were operating; CWPs lA and 1B were operating during the first six days, and CWPs 2A and

2C were operating during the final days. Cooling water flow during the period of two pump

operation averaged 1.616 x 106 m

3 (426.95 x 106 gals). During the period 28 July through 6

August, there were generally four CWPs operating, CWPs lA and IB for Unit 1 and CWPs

2A and 2C for Unit 2. Cooling water flow under four CWP operation averaged 2. 868 x 106

3 (757.73 x 106 gal).

Biofouling and Clogging Observations

Test Frame Observations. Observations made on the treated and untreated 3.0 mm

mesh test panels suspended at the face of the Bowline Point cooling water intake structure

between 26 April and 15 June 1993 are presented in Attachment 3. It should be noted that due

to the unrestricted flow potential around the test frames and the uneven water withdrawal among

the intake bays , the comparison between the inside and outside TSK velocity meters did not

yield usable results, and was terminated following 6 May 1993.

For the first three weeks of test mesh deployment (26 April - 14 May 1993), the mesh of all

four test panels remained open with only the occasional presence of decaying leaf litter, aquatic

vegetation , and live Gammarus recorded. Fine brown sediment was recorded on the nets on

11 May which continued to buildup on the panels over the remainder of the survey becoming

the principle mesh blocking component. When the mesh observations were terminated on 15

Lawler, Matusky & Skelly Engineers
TABLE 5-1

CIRCULATING WATER PUMP OPERATION AND COOLING WATER FLOW

BOWLINE POINT FINE MESH BARRIER NET EVALUATION STUDY

OPERATING CIRCULATING WATER PUMP 1A 1B 1C 2A 

c ~
June, the mesh panels were approximately 50 to 75 % blocked, with fine sediment and

filamentous algae the principle clogging factors. Overall there was no consistent difference

between mesh clogging for the treated and untreated meshes.

Test Panel Observations. Test panels constructed of fine mesh barrier net material

deployed at the surface, mid-depth, and bottom of Bowline Pond to monitor biofouling and

mesh clogging were evaluated on 3 and 17 August, and on 23-24 August when the fine mesh

barrier net was removed. Photographs of the test panels were taken on 3 and 17 August.

Observational information on the test panels is presented in Table 5-

Observational information indicated that clogging and biofouling started and was greatest at the

surface, with temporal blockage of the test panels proceeding from surface to bottom. A fine

brown silt was the principle mesh clogging factor followed by a filamentous algae. By the end

of the six week study period, the surface panels were completely blocked by the fine silt and

filamentous algae. The mid-depth panels were approximately 50% blocked, with blockage

ranging from 25% for the N3-N4 panel to 95% blockage for the NI-N2 panel. Blockage of the

bottom panels at the end of the study period ranged from 40% for the N3-N4 panel to 90% for

the 53-54 panel (bottom test panel was probably resting on bottom following 5-4 pile breakage

on 5 August), with an overall average blockage of approximately 50%. One interesting

observation was the substantially lower clogging and biofouling noted for the panels suspended

between pilings N3 and N4 compared to the other locations. In general , mesh blockage was

greatest for the test panels located closest to the bulkhead (N I- , and 51-52) and lowest for

the panels located near the apex of the barrier net (N3- , and 53-54). Net clogging was

primarily caused by fine silt, with the higher degree of net clogging noted near the bulkhead

probably related to increased silt suspension due to shallower water depth, and wave reflection

. from the bulkhead sheet piling.

Velocity Information. Due to the extensive build-up of debris on the intake trash racks

following the removal of the 9.5 mm mesh barrier net on 6 June 1993, no velocity information

was obtained at the intake during the fine mesh barrier net evaluation stUdy period. Velocity

information periodically recorded at locations behind the fine mesh barrier net is presented 

5-6

Lawler, Matusky & Skelly Engineers
0..

.,.

TABLE 5-

0 mm MESH TEST PANEL OBSERVATION INFORMATION

BOWLINE POINT FINE MESH BARRIER NET EVALUATION STUDY

July-August 1993

TEST

PANEL TEST PANEL LOCATION BETWEEN PILINGS

DATE DEPTH S1- S3- N3- N1-

3 Aug 93 Surface 95% blockage by fine silt 90-95% blockage by fine silt 20% blockage by fine silt 95% blockage by fine silt

Mid-Depth 30% blockage by fine silt and 10% blockage, some bryozoans Very light bryozoans 20% blockage, some bryozoans

filamentous algae

Bottom No blockage, some bryozoans 10% blockage, some bryozoans Very light bryozoans 10% blockage, some bryozoans

17 Aug 93 Surface 90-95% blockage by fine silt 95% blockage by fine silt and 80-85% blockage by fine silt 98% blockage by fine silt

and filamentous algae filamentous algae and filamentous algae and filamentous algae

Mid-Depth 60% blockage by fine silt and 50% blockage by fine silt and 5% blockage by fine silt 90% blockage by fine silt

filamentous algae filamentous algae and filamentous algae

Bottom 50% blockage by filamentous 80% blockage by fine silt 20% blockage by fine silt 60-70% blockage by fine silt

algae and fine silt and filamentous algae

23 -24 Aug 93 Surface 98% blockage by fine silt 98% blockage by fine silt 90% blockage by fine silt 99% blockage by fine silt

and filamentous algae and filamentous algae and filamentous algae and filamentous algae

Mid-Depth 70% blockage by fine silt 75% blockage by fine silt 25% blockage by fine silt 95% blockage by fine silt

and filamentous algae and filamentous algae and filamentous algae

Bottom 70% blockage by fine silt 90% blockage by fine silt 40% blockage by fine silt 80% blockage by fine silt

and filamentous algae and filamentous algae

5Aug93-Piling S4 breaks at sediment interface. Vertical angle 10-20 degrees. Bottom test panel resting on bottom,
Table 5-3. Velocity information recorded prior to the installation of the net on 20 July 1993

is also presented in Table 5-

The first indication of reduced flow, based on water velocity profile information recorded

behind the barrier net, was noted at mid-depth in the vicinity of the belly of the net (Figure 4-4)

which is probably related to a general build-up and accumulation of debris and immature

jellyfish, During the initial surveys, lower water velocity values were recorded from mid-depth

to bottom indicating that clogging and therefore lower net filtration efficiency started in this

area. Eventually the filtration efficiency of the entire net was affected with the net acting as

a dam, Le., water observed spilling over the top of the barrier net. Maximum clogging was

noted during the first week of August especially at the south side location, In general , net

cleaning at the end of the first week of August restored the filtering capability of the net.

Diver observations during net cleaning indicated that the net was clogged by a fine brown silt

that cleaned with the high pressure water jet. The principle problem noted with the water

pressure cleaning of the net was the small area that could be cleaned at one time due to the

small size of the device. The divers also observed that due to the heavy build-up of debris on

the intake screens resulting in a 45 cm (18 in) water differential at the trash racks, the greatest

currents were at the surface with only minimal flow below one meter. Divers removed the

debris build-up from the intake trash racks starting on 16 August; however, there are no

velocity profiles conducted after 16 August to determine if the more equal surface to bottom

water withdrawal affected the net.

Biological Monitoring

Fine Mesh Barrier Net Ichthyoplankton Program

Species Inventory, Abundance, and Percent Composition.

Ichthyoplankton sampling using a lO,2-cm diameter trash pump was conducted at the BPGS

cooling water intake between 19 July and 16 August, and Bowline Pond plankton net sampling

Lawler, Matusky & Skelly Engineers
TABLE 5-

WATER VELOCITY (em Is) RECORDED BY DEPTH

BElDND THE FINE MESH BARRIER NET

July - August 1993

AVERAGE WATER VELOCITY (cm/s) AND RANGE

DATE DEPTH (m) LOCATION A LOCATION B LOCATION C LOCATION D

20 Jut 2.4 (1.8 - 3.4) 6 (2.7 - 4. 5 (2. 7 - 8.

0 (1.5 - 2.4) 2 (2.4 - 4. 8 (0. 6 - 2.4)

1 (1.2 - 3. 1.3 (0. 6 - 1.8) 6 (1.5 - 7.

, Jul 1.0 7 (0, 3 - 4. 1.3 (0.3 - 2. 1 (1.5 - 4. 1.5 (0.0 - 2.

8 (0. 3 - 1.5) 4 (~. 6 - 1. 5 (~. 9 - 1. 5 (-3.4 - 2.

9 (~. 3 - 2. 2 (- 1.2 - 2. 1.0 (0.0 - 2. 8 (0.0 - 1.5)

1.4 (0.0 - 5. 1.0 (~. 6 - 3. 1 (- 1.5 - 3 (~.6 - 1.2)

1.3 (~.9 - 3.4) 3 (~. 9 - 2. 6 (0. 6 - 5. 0 (0.9 - 3.4)

30 Jut 1.0 7 (1.5 - 4. 8 (1.5 - 3.4) 0(2. 3 (1.2 - 3.

9 (1.5 - 4. 7 (1.5 - 4. 6 (2. 1 - 3. 1.8 (1.2 - 3.

2 (3.0 - 7. 2 (2. 7 - 7. 6(2. 1.8 (1.2 - 2.4)

3 (1.5 - 3. 5 (1.5 - 4. 6 (0.6 - 4. 3 (1.5 - 3.

0 (2. 7 - 3.4) 3 (2. 1 - 5. 1.8 (1.2 - 2. 3 (1.5 - 2.

2 Aug 1.0 3 (1.2 - 7. 3 (~. 6 - 2. 8 (-1.2 - 2. 7 (0.3 - 7.

5 (4.9 - 12. 1.4 (-2.4 - 3.4) 1.0 (~. 3 - 2.4) 1.9 (~. 9 - 6.

5.4 (3. 0 - 8. 2 (-28.0 - 6. 1.3 (- 1 - 1.1 (~. 6 - 2.

1.4 (- 3 - 0. 1.9 (~. 9 - 4. 8 (~. 9 - 3. 1.4 (~. 3 - 4.

1 (1.5 - 4. 5 (~. 9 - 1. 5 (-1.2 - 2. 6 (~. 6 - 2.

5 Aug 1.0 6 (3.0 - 15. 83. 1 (48. 8 - 140. 1.5 (0.0 - 6.

2(7. 8 (0.0 - 3. 1.0 (0. 0 - 3.

3.4 (0.0 - 6. 5 (0.0 - 3.

0 (0.0 - 4. 8 (3.0 - 7.

7.4 (6. 15. 6 (1. 5 - 15.

6.3 (4.6 - 9. 6 (1. 5 - 15. 0 (0.0 - 6.

12 Aug 1.0 3 (- 0 - 18. 1 (0. 9 - 3.4) 0 (1.5 - 3. 8 (2.4 - 3.

3 (- 4 - 18. 2 (0.0 - 0. 0 (1.5 - 2. 7 (2.4 - 3.

7 (- 5 - 19. 0.4 (0.0 - 0. 9 (2. 7 - 3. 1 (3.0 - 3.4)

4 (- 5 - 18. 1 (0.0 - 0. 3 (2.7 - 3. 2 (3.0 - 3.4)

3 (1.5 - 2. 2 (~. 6 - 0. 0 (2.7 - 3. 9 (2.4 - 3.

0 (- 0 - 21.3) 5 (0. 0 - 1.5) 3 (1.5 - 2.

Location A = NI-N2; Location B = N3-N4; Location C = S3-S4; Location D = SI-S2.
was conducted between 19 July and 18 August 1993. Ichthyoplankton representing six taxa and

six separate families were collected over the course of the evaluation program (Table 5-4); bay

anchovy, gobi (unidentified species), northern pipefish, silverside (unidentified species), striped

bass, and weakfish. Four taxa were collected inside the barrier net, and four taxa were

collected in Bowline Pond outside of the barrier net, with bay anchovy and gobi collected at

locations both inside and outside of the barrier net. Silvers ides (three specimens) and striped

bass (one specimen) were only collected at inside barrier net locations, while weakfish (three

specimens) and northern pipefish (one specimen) were only collected at locations outside of the

barrier net.

A total of 183 fish larvae were collected, with the dominant taxon collected the bay anchovy

accounting for 84.7% (155 individuals) of the total catch. An unidentified gobi ranked second

in overall abundance with 12 specimens or 6.6% of the total collection. The other four taxa

identified in the Bowline Point intake, and Bowline Pond ichthyoplankton collections totaled

eight specimens or 4.4% of the total. An additional eight specimens were collected by the

intake pump sampler, but were damaged and could not be identified.

BPGS Intake Pump Sampling Results.

Intake sampling using a 4. in. trash pump commenced on 19 July and was terminated on 16

August 1993. A total of 67 samples were collected, 32 samples at the Unit 1 intake and 35

samples at the Unit 2 intake. Of the 67 samples collected, 42 or 62.7% were analyzed. All

samples from the first two weeks were analyzed, but only samples from selected dates were

analyzed following 3 August due to low ichthyolpanlcton abundance. A total of 64 fish larvae

were identified in the 42 samples, with the bay anchovy (43 individuals) accounting for 67.

of the total (Table 5-4), An unidentified gobi ranked second in total abundance with 11

individuals or 17.2 % of the total collection.

A daily summary of the cooling water intake pump entrainment collection information is

presented in Table 5- , with the per sample information presented in Attachment 4. Information

in Table 5-5 is based on the formula:

Lawler, Matusky & Skelly Engineers
TABLE 5-4

SPECIES INVENTORY AND ABUNDANCE BY LOCATION

FINE MESH BARRIER NET EVALUATION STUDY - 1993

ABUNDANCE BY COLLECTION LOCATION

INSIDE OUSIDE

INTAKE PLANKTON PLANKTON

FAMILY SCIENTIFIC NAME COMMON NAME PUMP NET NET

Atherinidae Unknown Silverside

Engraul~dae Anchoa mitchilli Bay anchovy

Gobiidae Unknown Gobi

Percichthyidae Moro1U! saxatilis Striped bass

Sciaenidae Cynosdon regalis Weakfish

Syngnathidae SyngTlllthus fuscus Northern pipefish

UID

Total
TABLE 5-

ICHTHYOPLANKTON CONCENTRATION (No./l000 m

BASED ON INTAKE PUMP SAMPLES

A VERAGE PER DATE CONCENTRATION (No.llOOO m

NUMBER OF SAMPLES

COLLECTED/ANALYZED UNIT 1 UNIT 2 INTAKE

DATE UNIT 1 UNIT 2 TOTAL TOTAL TOTAL

19 Jul 1/1 733, 923. 733, 923.

20 Jul 1/1 31.1 62. 31.1 62.

21 Jul 1/1 28.4 28.4

22 Jul 1/1

23 Jul 3/3 58.4 87.4 58.4 87.4

24 Jul

25 Jul

26 Jul 3/3 19.1

27 Jul 3/3 19.

28 Jul 3/3 3/3 39. 23.29 Jul 3/3 3/3

30 Jul 2/2 3/3 117.4 132. 47, 52.

31 Jul

1 Aug

2 Aug 3/3 3/3

3 Aug 3/0 3/0

4 Aug 1/1 1/1

5 Aug 2/0 2/0

6 Aug 2/1 I/O

7 Aug

8 Aug

9 Aug 3/3

10 Aug 3/0

11 Aug 3/112 Aug 2/0

13 Aug 3/114 Aug

15 Aug

16 Aug 2/1

:3A Hay anchovy. Total All lchthyoplankton.
larvae in a samPle

1000

VolumeFiltered (m

Bay anchovy were collected between 19 and 30 July - no bay anchovy were collected in the

month of August. The greatest concentration of bay anchovy larvae were noted during 19 July,

the first sampling date, conducted prior to the deployment of the fine mesh barrier net. Overall

very few bay anchovy larvae were collected at the cooling water intake structure during the six

week fine mesh barrier net evaluation program. The 1993 ichthyoplankton collection data

suggests that bay anchory abundance in Haverstraw Bay/Bowline Pond peaked earlier in July,

with fine mesh barrier net deployment and sampling occuring near the end of the peak.

Length frequency information for the bay anchovy collected at the cooling water intake structure

is presented in Table 5-6. A total of 37 bay anchovy were measured for total length; total

length ranged from 6.0 mm to 11.2 mm, with an overall average total length of 8.4 mm, Due

to the limited number of larvae collected, no growth pattern trend over the six week study

period is evident.

Bowline Pond Plankton Net Samples.

Plankton net samples were collected at two stations; one along the north side and the second

along the south side, outside of the fine mesh barrier net between 19 July and 16 August 1993.

Samples collected on 19 July are pre-deployment net samples while the remaining outside net

samples were collected following the complete deployment of the net. A total of 94 surface and

bottom composite samples were collected outside of the barrier net with 62 samples analyzed

(66.0%). As noted earlier, only selected samples following 3 August were analyzed due to low

ichthyoplankton abundance, A total of 88 fish larvae were identified in the 62 samples analyzed

with bay anchovy the dominant species; 83 individuals accounting for 94.3% of the total (Table

5-4).

Depth composite plankton net samples were collected inside the deployed barrier net between

22 July and 16 August. A total of 44 samples were collected, with 28 samples or 63.

Lawler, Matusky & Skelly Engineers
Table 5-6

BAY ANCHOVY LENGTH INTERVAL INFORMATION

COOLING WATER INTAKE PUMP SAMPlES

LENGTHINTERVAL

5-4.

1-4.

6-5.

6-6.

1-6.

6-7.

6-6,

1-8.

6-9.6-10.

10. 10,10.6-11.11. 11.11.6-12.12. 12.12,6-13.13. 13.13.6-14.

14. 14.14.6-15.15. 15.15.6-16.16. 16.16.6-17.

17. 17.17.6-18.18. 18.18.6-19.19. 19,19.6-20.

20. 20.20.6-21.21. 21.21.6-22,

22. 22.22.6-23.

TOTAL CAUGHTTOTAL ANAL VZED

1993 SAMPLE DATE

19JUL 20JUL 21JUL 22JUL 23JUL 26JUL 27JUL 28JUL 29JUL 3OJUL 2AUG 3AUG 4AUG 5AUG 6AUG 9AUG 10AUG 11AU 12AU 13AU 16AU

11. 10.

MINIMUM LENGTH 6.MAXIMUM LENGTH 9.MEAN LENGTH 7.
analyzed. Bay anchovy was the dominant species collected by plankton nets inside the barrier

net with 29 individuals collected representing 93.5% of the 31 larvae identified (Table 5-4),

Inside and outside ichthyoplankton collection information based on depth composite plankton

net samples is summarized in Table 5-7. Per date sample collection information is presented

in Attachment 5. At outside barrier net stations, bay anchovy were identified in samples from

19 July through 13 August. Peak concentration of bay anchovy was noted during the first two

weeks of the study period, with very few larvae collected following the end of July. The peak

concentration of bay anchovy larvae inside the barrier net, corresponded in time to the outside

peak, however, there were no bay anchovy larvae identified in inside samples after the first

week of August. In general, there was no consistent difference in bay anchovy concentrations

noted between inside and outside barrier net samples, however, this may be due to the very low

numbers of organisms collected during the study period.

Length frequency data for bay anchovy collected at stations outside and inside of the fine mesh

barrier net are summarized in Tables 5-8 and 5-9, respectively. Length information for the

outside barrier net stations covers the entire study period, with length data available from 19

July through 13 August. Bay anchovy total length gradually increased over the study period

from an average length of 8.7 mm during the first week of sampling to 17.6 mm on 13 August.

Continuous recruitment of young larvae was evident through the end of July. Similar average

total length and length range was noted for bay anchovy collected inside the barrier net when

compared to outside barrier net values, however, the small sample size precludes any

comparison.

Average daily Bowline Pond water quality information recorded during the fine mesh barrier

net evaluation period is presented in Table 5-10. Per sample water quality information recorded

by depth and time of day is presented in Attachment 6. A verage daily water temperature

ranged from 24.5OC (27 July 1993) to 26.4 oC (4 August 1993), with an overall average of

25.4OC, In general , the higher water temperatures were recorded at the surface and the lowest

water temperatures were recorded at the bottom (Attachment 6). The average specific

conductance over the study period was 8827 J-Lmhos/cm at 25O C, with a range from 6856

Lawler, Matusky & Skelly Engineers
...

TABLE 5-

ICHTHYOPLANKTON CONCENTRATIONS BASED ON 0.5 m PLANKTON NET SAMPLES

COLLECTED AT STATIONS INSIDE AND OUTSIDE THE FINE MESH BARRIER NET

A VERAGE PER DATE CONCENTRA nON (No,l1000 m

NUMBER OF COMPOSITE SAMPLES

COLLECTED! ANALYZED ,:NSIDE OUTSIDE

DATE INSIDE OUTSIDE TOTAL TOTAL

19 Jul 4/4 55.5 55.

20 Jul21 Jul 2/2 26. 28.4922 Jul 1/1 2/2 87. 87. 16. 16.1

23 Jul 3/3 6/6 42.4 42.424 Jul25 Jul

26 Jul 3/3 6/6 158, 158.

27 Jul 3/3 6/6 40. 40.

28 Jul 3/3 6/6 60. 60. 11.3 11.3

29 Jul 3/3 6/6 62. 73.430 Jul 3/3 6/6 30. 41.0 106, 112.31 Jul

1 Aug

2 Aug 3/3 6/6 37. 37. 28.3 33.

3 Aug 3/0 6/0

4 Aug 1/1 2/2 31.2 31.2

5 Aug 2/0 4/0

6 Aug 1/1 2/2

7 Aug

8 Aug9 Aug 2/1 4/2 15. 15.

10 Aug 3/0 6/011 Aug 3/1 6/212 Aug 3/0 6/013 Aug 3/1 6/2 15, 15.14 Aug15 Aug16 Aug 1/1 2/2 18.

IA - Rav anchovv. Total - All lchthvnlankton collected,
...

Table !HI 

BAY ANCHOVY LENGTH INTERVAL INFORMATIONPLANKTON NET SAMPlES COLLECTED OUTSIDE THE BARRIER NET

1993 SAMPLE DATE

LENGTH

INTERVAL 19JUL 20 JUL 21 JUL 22 JUL 23 JUL 26 JUL 27 JUL 28 JUL 29 JUL 30 JUL 2AUG 3AUG 4AUG 5AUG 6AUG 9AUG 10AUG IIAUG 12AUG 13AUG 16AUG 17 AUG 18AUG

5-4,

1-4,

6-5,

&-6,

1-6,

6-7,&-8,

1-8,

6-9,6-10,

10, 10.10,6-11,11, 11,11,6-12,12, 12,12.6-13.13, 13,13.6-14,14, 14,14,6-15,15, 15,15,6-16,16, 16,16,6-17,

17. 17,17.6-16.18, 18,18,6-19,19, 19,19,6-20,

20, 20,

20,6-21.21. 21.5

21,6-22,

22. 22.5

22,6-23,

TOTAL CAUGHTTOTALANALVZEDMINIMUM LENGTHMAXIMUM LENGTH 13, 10, 12, 12, 11, 12, 22,

MEAN LENGTH 12, 14, 13, 17,
Table 5-9

BAY ANCHOVY LENGTH INTERVAL INFORMATIONPLANKTON NET SAMPLES COLLECTED INSIDE THE BARRIER NET

LENGTHINTERVAL

5-4.

1-4.

6-5.6-6.

1-6.

6-7.

6-8.

1-8.

6-9.

6-10,

10, 10.10.6-11.11. 11.

11.6-12.12, 12.12,6-13,13. 13,13,6-14,

14. 14.14.6-15.15. 15.

15.6-16.16, 16,

16,6-17,17. 17.17.6-18,18, 18,18.6-19.19. 19.19.6-20.

20. 20.20.6-21.21. 21.

21.6-22,22. 22.22,6-23,

:;)

TOTAL CAUGHTTOTAL ANAL VIED

MINIMUM LENGTHMAXIMUM LENGTHMEAN LENGTH

1993 SAMPlE DATE

19JUL 20JUL 21JUL 22JUL 23JUL 26JUL 27JUL 28JUL 29JUL 3OJUL 2AUG 3AUG 4AUG 5AUG 6AUG 9AUG 10AUG 11AU 12AU 13AU 16AU 17AUG 18AU

10, 10. 10. 13,

12. 10.
Table 5-

AVERAGE DAILY WATER QUALITY INFORMATION

BOWLINE POINT FINE MESH BARRIER NET EVALUATION PROGRAM

SPECIFIC DISSOLVED SECCHI

CONDUCTANCE SALINITY OXYGEN DISK

DATE Celsius umhos/cm 25 C

(pp

25. 10500.

24. 9333. 127.

* No sample collected

c::- 1 
JLmhos/cm at 250C recorded on 12 August to 10,789 JLmhos/cm at 250C recorded on 23 July.

The highest conductivity values were recorded at the bottom and the lowest at the surface

(Attachment 6). A verage daily salinity ranged from 4.0 (9 August) to 6.3 (23 July) parts per

thousand (ppt), and averaged 5.0 ppt. Salinity generally decreased over the study period with

the highest values recorded during the first week of study and the lowest values recorded during

the middle of August. There was very little variability in salinity noted by depth. Dissolved

oxygen was consistently high over the study period averaging 8. 1 mg/l with a daily average

range of 6.0 to 7,9 mg/l. Water transparency based on Secchi disk readings ranged from 77.

to 127,0 cm and averaged 89.2 cm.

Additional Samples

Evaluation samples were concentrated around the fine mesh barrier net, during 27 July and 18

August additional 0.5 m plankton net samples were conducted in Bowline Pond away from the

barrier net (Table 5- 11) to detennine gross abundance, and to determine if there was a

distributional pattern to fish larvae in Bowline Pond that could affect the results of sampling in

the immediate vicinity of the barrier net. No bay anchovy larvae were collected in the longer

duration open Pond samples, and fish larvae concentrations were generally the same as those

collected along the north and south side of the barrier net.

During the period 9 through 16 August, one of the intake sample pumps was placed on the

barrier net work barge and used to collect pump samples outside of the barrier net at a position

between pilings S2 and S3. No bay anchovy larvae were collected in the pump samples

conducted outside of the barrier net (Attachment 3).

3.4 Total Length Body Depth Relationship. A total of 134 bay anchovy larvae measured

for total length were also measured for body depth to determine the accuracy of the relationship

used to indicate the mesh size for the fine mesh barrier net. The results of the measurements

are presented in Attachment 7. The resulting linear regression of total length versus body depth

for bay anchovy was determined to be:

Body Depth (BD) = -0.27533 + 0. 11274 (Total length)

Lawler, Matusky & Skelly Engineers
TABLE 5-

BOWLINE POINT FINE MESH BARRIER NET EVALUATION STUDY

ICHTHYOPLANKTON COLLECTION INFORMATION

BOWLINE POND O. 5m PLANKTON NET - SPECIAL SAMPLES 

27 -Jul- APEX- 1047 11:59 52. 19. 19.

18-Aug- APEXAPEX- 1223 1224 1225

1226

10:5211:02

11:2511:33

86.85.88.

83.

11. 11.
The R squared value for the equation is 0.92216. The linear regression equation for spottail

shiner used in estimating mesh exclusion potential was:

Body Depth (BD) 

28 + 0. 17 (Total length)

The R squared value for the spottail shiner equation was 0.95. The regression equation

developed for bay anchovy from Bowline Pond predicts that a larvae measuring 13.0 mm in

total length would have a body depth of 1.2 mm, and a larvae measuring 15.5 mm in total

length would have a body depth of 1.5 mm. The body depth values for bay anchovy larvae

obtained under the fine mesh barrier net evaluation study were approximately 4D% of the values

predicted from the use of the regression equation for spottail shiner (Schneeberger and Jude

1981). The body depth results indicate that based on mesh exclusion potential only, an effective

Bowline Pond barrier net would require net mesh openings of 1.0 to 1. 5 mm. Based on the

1993 evaluation study a net with mesh openings this small would not be deployable due to the

observed clogging rate.

Lawler, Matusky & Skelly Engineers
CHAPTER 6

SUMMARY AND CONCLUSIONS

GENERAL PROGRAM DESCRIPTION

Orange and Rockland Utilities, Incorporated (ORU) contracted Lawler, Matusky & Skelly

Engineers (LMS) to evaluate the feasibility of deploying a fine mesh barrier net at the cooling

wat!?r intake of the Bowline Point Generating Station (BPGS) during the spring and summer

months as a means of mitigating ichthyoplankton entrainment. The feasibility study was

conducted in two phases; Phase I was conducted during 1992 and Phase II was conducted during

1993.

Phase I consisted of monitoring several different mesh panels deployed in Bowline Pond during

the period June through September for biofouling and clogging, preparing a comprehensive

report on Bowline Pond and Haverstraw Bay ichthyoplankton, and recording water velocities

in Bowline Pond over a complete tidal cycle. Results of the Phase I studies indicated that a fine

mesh barrier net could be deployed during the spring-summer period, the period which

corresponds to the seasonal peak abundance period for ichthyoplankton, however, maintaining

the filtering potential of the net would require substantial maintenance. Velocity data collected

under Phase I suggested that the barrier net could be deployed at several locations in Bowline

Pond including the inlet to the Pond and the area around the BPGS cooling water intake

structure currently used to deploy the 9.5 mm mesh barrier net.

Phase II of the fine mesh barrier net evaluation program had as its primary objective the design

deployment, and monitoring of a fine mesh barrier net at the BPGS cooling water intake

structure. Tasks to be completed under the Phase II study were:

1. Select the location for the deployment of the fine mesh barrier net.

2. Select the target ichthyoplankton population which would be used to determine

the effectiveness of the barrier net.

Lawler, Matusky & Skelly Engineers
3. Determine the barrier net mesh size that would be effective at excluding the

target ichthyoplankton population.

4. Design a fine mesh barrier net taking into consideration: maintenance of low

through mesh water velocities , potential heavy debris loading, clogging and

biofouling, easy deployment technique, and easy net retrieval/removal for

maintenance.

5. Develop and conduct a sampling program to determine the effectiveness of the

fine mesh barrier net at limiting the movement of ichthyoplankton.

2 PHASE II PROGRAM

1 Barrier Net Design Considerations

Deployment Location. Bowline Pond is within the property boundary lines of BPGS,

however, there are no restrictions on use of the waterbody by the general public. BPGS

personnel have docking facilities along the breakwall north of the intake structure for the

mooring of the oil boom deployment boat. ORU also maintains a boat launch ramp for

company employees on Bowline Pond. Given the use pattern of Bowline Pond by the general

public and BPGS personnel , the successful deployment of a 9.5 mm mesh barrier net, and

favorable physical conditions including low water velocities and bottom configuration, the only

logical location for deployment of the fine mesh barrier net was in the immediate vicinity of the

cooling water intake structure, i.e., in the same general area where the 9.5 mm mesh barrier

net is seasonally deployed. Deployment of the fine mesh barrier net in the same general

vicinity as the 9. 5 mm mesh barrier net, has the added advantage of using applicable equipment

and techniques currently used to deploy the larger mesh net.

Water velocity along the fine mesh barrier net deployment transect was an important factor in

selecting the location for net deployment. Average water velocities recorded at low slack tidal

conditions at the inlet to Bowline Pond and along the 9.5 mm barrier net transect under two

cooling water pump (CWP) operation were 30. 76 cm/s (1.01 fps) and 10. 08 cm/s (0.33 fps),

respectively. Lower average water velocities along the existing barrier net transect was another

reason for selecting this location for deployment of the fine mesh barrier net.

Lawler, Matusky & Skelly Engineers
Selection of Target Species. A review of ichthyoplankton data from Bowline Pond and

Haverstraw Bay indicated that the numerically dominant species is the bay anchovy accounting

for over 80% of all larvae collected. Bay anchovy larvae are present in the vicinity of BPGS

from early June through August with the longterm peak ahundance period nOted from mid-July

through mid-August. During the peak abundance period, the life stage of the overwhelming

majority of bay anchovy larvae are post yolk-sacs, with average total lengths ranging from 13.

to 15. 5 mm. Based on the numerical dominance of bay anchovy post yolk-sac larvae in the

vicinity of BPGS, this species was selected as the target species for the evaluation of the

effectiveness of the fine mesh barrier net. A six week evaluation period from mid-July through

August was selected, corresponding to the period of peak abundance of the post yolk-sac life

stage.

Selection of Net Material and Mesh Size Opening. A nylon mesh with a nominal

opening of 3.0 mm was selected for the fine mesh barrier net. The net type and mesh size

selected was based on material availability, optimal percent open area , cost , and exclusion

pOtential. Body size measurements (body depth, width) for bay anchovy post yolk-sac larvae

were not available in the literature for use in estimating mesh exclusion pOtential. To assist in

selecting the size of the fine mesh barrier net mesh size opening, regression equations for body

depth versus total body length for fish larvae with body shapes similar to the bay anchovy were

examined. It was estimated using a regression equation developed for spottail shiner

(Schneeberger and Jude 1981) that the body depth for 13.0 and 15. 5 mm tOtal length bay

anchovy larvae would be 1.9 mm and 2.4 mm, respectively. A regression equation for bay

anchovy body depth versus total length was subsequently developed from data collected during

the fine mesh barrier net evaluation study; the body depth for a 13.0 mm and 15.5 mm total

length bay anchovy larvae was calculated to be 1.2 mm and 1.5 mm, respectively.

Under the Phase I study, it was nOted that a polyethylene material exhibited lower biofoulingclogging and cleaned easier than nylon mesh materials. Various net manufacturing companies

were contacted and it was determined that polyethylene material with a 3.0 mm mesh opening

was nOt available in sizes needed to economically construct the Bowline Point fine mesh barrier

net. Nylon netting, untreated to maintain its white color and therefore higher visibility and to

Lawler, Matusky & Skelly Engineers
maintain the maximum percent open area , was selected for the fine mesh barrier net. Again

net manufacturers were contacted, and after evaluating several mesh configurations and twine

sizes, a 3.0 mm Delta mesh net constructed of 35 lb. twine was selected. A dual net system

was designed for deployment at BPGS; the 3.0 mm fine mesh net supported by a nylon net with

4.45 cm square mesh opening.

1.4 Barrier Net Design. Given the high resistance of the fine mesh net to the free passage

of water (approximately 50% open area) and the greater potential for clogging and biofouling,

the deployment of the fine mesh net using the anchor system deployment technique of the 9.

mm mesh barrier net was nor considered adequate. A system employing wooden pilings was

considered necessary to support the fine mesh barrier net. Several piling installation

configurations were investigated with the prime concern related to optimizing the surface area

of the net which would yield low through mesh velocities. The final design called for the

pilings to be installed in a ' V' configuration around the intake structure with the point of the

V' 45. 7 m our from the center of the face of the intake structure. Pilings would be installed

approximately 15 m apart. The actual area along the piling transect at mean low water was

calculated as 1194 m2 (12 849 ft2). Using 50% of the transect area as equal to the percent open

area of the fine mesh barrier net, and the cooling water volume of 2392. /min (4 CWPs

unthrottled) , the average through mesh water velocity would be 3. 34 cm/s (0. 11 ips).

The net was constructed in panels for deployment between the wooden pilings. Net panels were

constructed 4.5 m longer than the distance between attachment points to permit easy deployment

and to maximize net filtration area. Two chains were added to the bottom of the net panels to

ensure the bottom seal during deployment. The use of panels was intended to facilitate net

deployment and removal for cleaning, however, due to time and economic constraints the

prototype net was deployed in one piece with the net panels sewn together prior to deployment.

Floats were attached to the surface line of the net at 30 cm intervals, however , as the net

clogged, water pressure pulled the tOp of the net under, additional floatation was added which

helped to maintain the tOp of the net at the waters surface. Steel cables were stretched between

and secured to the bottom and top of the pilings for attachment of the net panels.

6-4

Lawler, Matusky & Skelly Engineers
Barrier Net Deployment and Observations

Wooden pilings were installed during 12- 13 July, and the fine mesh barrier net was deployed

during 19-21 July, with deployment complete at 1400 hrs on 21 July. The steps for barrier net

deployment were:

1. Steel cables were installed between pilings, and the end pilings and the bulkhead.

Cables were secured around each piling at the top (approximately 1.5 m above

high water) and bottom.

2. The barrier net was loaded on the work platform, and attached to the bulkhead

south of the intake structure using the existing eyebolts,

3. Nylon attachment lines were secured to the float line and bottom line of the net

at 6. 5 m intervals.

4. The bottom and top of the net were attached to the pilings with the point of

attachment corresponding to the juncture of two net panels. The bottom

attachment lines were passed under the bottom steel cable and brought to the

surface cable and secured. The float line attachment lines were secured to the

upper steel cable. (Securing of all bottom lines was done by divers.

5. Divers inspected the net following installation between each piling to ensure that

the bottom of the net was in contact with the bottom sediments.

Initial observations of the deployed fine mesh barrier net were very good, divers found that the

bottom attachment technique ensured a good bottom seal , and the floats on the surface line were

maintaining the top of the net at the waters surface. The presence of large numbers of

immature jellyfish in Bowline Pond following net deployment immediately started clogging the

net, with the resultant water pressure forcing the top of the net under the surface of the water

in several places. Additional flotation was added to the net, and manual cleaning of the net was

initiated: Manual cleaning of the deployed net had only limited success and this only at the

surface, with the primary technique of maintaining the net at the waters surface the addition of

floatation. The jellyfish which remained in high concentrations in the Pond through the end of

July, resulted in continuous net submergence problems.

In addition to the jellyfish, net clogging due to very fine silt was evident. As noted with the

jellyfish, as the net clogged the resultant water pressure forced the top of the net under the

Lawler, Matusky & Skelly Engineers
waters surface. Divers were contacted to attempt to clean the net in place during the first week

of August. The divers using a Hydrolaser, a high pressure water spray, were able to clean the

net in three days. Tension on the net prior to the in situ cleaning was great enough to snap one

of the pilings (piling 54) at the bottom, however, the steel surface cable was adequate to hold

the piling at an angle of approximately 10- 15 degrees from vertical until the end of the study.

During the net cleaning, the divers noted very strong surface currents but very low subsurface

currents behind the barrier net. Heavy debris build-up (primarily sticks) on the cooling waters

intake fixed screens was noted during the latter part of July, and the divers attributed the uneven

flow pattern to the damming effect of the debris on the screens. (NOTE: Divers were

contracted to clean the BPGS fixed screens on 16 August 1993.

The fine mesh barrier net was removed without the aid of divers on 23-24 August. Upon

retrieval the net was observed to be in good shape with no holes, rips, or tears. The net was

heavily clogged primarily by fine silt with some filamentous algae noted at the top.

Barrier Net Effectiveness Evaluation

Ichthyoplankton samples collected using a pump at the BPGS intake, and 0.5 m diameter mouth

plankton nets at locations inside and outside of the barrier net were the primary method of

determining barrier net effectiveness. Over the study period, the concentration of

ichthyoplankton in Bowline Pond was extremely light which limited the ability to detect any

effectiveness of the net at limiting ichthyoplarJcton movement.

The greatest concentration of bay anchovy larvae was noted during the first week of the study

period. GeneraIly the concentration of larvae was similar between the cooling water intake and

inside the barrier net to the concentration recorded outside the barrier net. Length frequency

information for bay anchovy collected inside and outside the barrier net did not indicate any

difference. The low abundance levels of icthyoplankton in general and bay anchovy specificaIly

during the fine mesh barrier net evaluation study period does not permit the determination of

the biological effectiveness of the net.

Lawler, Matusky & Skelly Engineers
3 CONCLUSIONS

The Phase II study pointed out that a fine mesh barrier net could be deployed at the cooling

water intake sttucture of the Bowline Point Generating Station during the summer period when

the concentration of bay anchovy larvae is at its seasonal peak. Clogging of the net was a

significant problem, first by immature jellyfish and secondly by fine silt, however, a net

maintenance program incorporating periodic net cleaning should counter the clogging problem.

Biofouling was not observed to be a problem during the 1993 study period. Future net designs

should incorporate the ability to remove and/or replace net sections for cleaning, since in place

cleaning as done during the 1993 study is too slow, and does not result in complete cleaning.

A regular net maintenance program incorporating periodic net panel replacement or cleaning

should permit the deployment of a fine mesh barrier net over the entire spring/summer period.

Based on length frequency information the fine mesh barrier net should be effective at limiting

the enttainment of post yolk-sac white perch, striped bass, alewife, and blueback herring.

Concentrations of bay anchovy larvae in Bowline Pond during the study period were extremely

low. Over the course of the study a total of 67 pump samples and 138 plankton net samples

(44 inside and 94 outside) were collected, with 42 of the pump samples and 90 of the plankton

net samples (28 inside and 62 outside) analyzed. A total of 183 fish larvae were collected with

bay anchovy (155 individuals) accounting for 85% of the total. The number of larvae collected

precludes any determination of barrier net effectiveness based on larval exclusion.

Lawler, Matusky & Skelly Engineers
REFERENCES CITED

Bechtel. 1970. Orange and Rockland Utilities , Inc. Bowline Point Unit No. 1. Haverstraw

New York. Boring logs. Job No. 7757. Drawing No. C-4.

Browne, M. , LB. Glover, D.W. Moore, and D.W. Ballenger. 1981. In-situ biological and

engineering evaluation of fine-mesh profile-wire cylinders as powerplant intake screens.

Pages 36-46 In: P.B. Dorn and J.T, Johnson (eds) Advanced Intake Technology for

Power Plant Cooling Water Systems. Proceedings of the Workshop held at the SheratonHarbor Island Hotel April 22- , 1981.

Ecological Analysts , Incorporated (EA). 1981. Prototype wedge-wire screen intake module

study. Report prepared for Commonwealth Edison Company.

Edwards , S. , P. M. McGroddy, D. Lispi, and P. Dorn. 1981. Fine mesh screens and an

impingement-release system for marine fish larvae. Pages 128- 137. In: Dorn, P. B. and

T. Johnson (eds) Advanced Intake Technology for Power Plant Cooling Water Systems.

Proceedings of the Workshop held at the Sheraton-Harbor Island Hotel April 22- , 1981.

Fletcher, R. I. 1990. A review of reported fine mesh screen applications for high volume

water-intake systems, and recommendations for further investigations. Prepared for

Consolidate Edison Company of New York , Inc. 7 pp. plus attachments.

Hutchison , J.B. Jr. , and J.A. Matousek. 1988. Evaluation of a barrier net used to mitigate

fish impingement at a Hudson River power plant intake. Hudson River Monograph.

American Fisheries Society. Monograph No. 4:280-285.

Lawler, Matusky & Skelly Engineers (LMS). 1981. 1980 Hudson River studies at the

Bowline Point Generating Station. Report prepared for Orange and Rockland Utilities,

Inc.

Lawler, Matusky & Skelly Engineers (LMS). 1992a. Bowline Point fine mesh barrier net

evaluation study, progress report: June-September 1992. Progress report submitted to

Orange and Rockland Utilities, Inc. 7 October 1992.

Lawler, Matusky & Skelly Engineers (LMS). 1992b. Ichthyoplankton populations in

Haverstraw Bay and Bowline Pond. Report prepared for Orange and Rockland Utilities

Inc. October 1992.

Matousek, J. , M.V. Bonomo and J. B. Hutchison, Jr. 1981. A multi-gear fishery survey of

a Hudson River embayment used as a source of cooling water. Poster paper presented at

the Hudson River Fisheries Workshop sponsored by the Hudson River Environmental

Society, Norrie Point Field Station of Dutchess County Community College, September

1981.

Lawler, Matusky & Skelly Engineers
REFERENCES CITED

(Continued)

Normandeau Associates, Incorporated (NAI). 1993. Bowline Point Generating Station 1992

impingement studies. R- 12147.01. Report prepared for Orange and Rockland Utilities,

Inc. June 1993.

Orange and Rockland Utilities , Inc. , (ORU). 1993. Personal communication with W.

Parisen. Manager-Civil Engineering, Surveying and Construction Administration.

Schneeberger, P. J. and D.J. Jude. 1981. Use of fish larva morphometry to predict exclusion

capabilities of small-mesh screens at cooling-water intakes. Transactions of the American

Fisheries Society 110(2):246-252.

Taft~ III , E. , RH. Berger, J. Larsen , J. G. Holsapple, and L. Eberly. 1981. Laboratory

evaluation of larval fish impingement and diversion systems. pp. 138- 158. In: Dorn

B., and J.T. Johnson (eds). Advanced Intake Technology for Power Plant Cooling

Water Systems. Workshop Proceedings. 22-24 April 1981.

Tomljanovich, D.A., J. H. Heuer, and C.W. Voightlander. 1977. Investigations on the

protection of fish larvae at water intakes using fine-mesh screening. Tennessee Valley

Authority, Division of Forestry, Fisheries, and Wildlife Development, Technical Note

B22, Norris, TN, USA. 

Tomljanovich, D. , J. H. Heuer, and C.W. Voightlander. 1978. Investigations on the

protection of fish larvae at water intakes using fine-mesh screening. Pages 125- 139 In:

Sharma, RJ. and J.B. Palmer (eds), Larval Exclusion Systems for Power Plant Cooling

Water Intakes. Proceedings of Workshop Held at Shelter Island Inn, February 7- , 1978.

Weisberg, S.B., W. H. Burton, E. A. Ross, and F. Jacobs. 1984. The effects of screen slot

size screen diameter, and through-slot velocity on entrainment of estuarine

ichthyoplankton through wedge-wire screens. Report prepared for the Maryland Power

Plant Siting Program,

ZeitOun, I.H., J. A. Gulvas, and J.Z. Reynolds. 1981. Effectiveness of small mesh cylindrical

wedge-wire screens in reducing fish larvae entrainment at an offshore and an onshore

location of Lake Michigan. Pages 57-64. In: Dorn , P.B. and J.T. Johnson (eds)

Advanced Intake Technology for Power Plant Cooling Water Systems. Proceedings of

the Workshop held at SheratOn-Harbor Island Hotel , April 22- , 1981.

Lawler, Matusky & Skelly Engineers
26 APRIL 1993

IT ACHMENT 

BOWLINE POND SEDIMENT CORE LOGS
Data by Shy..,! -L- 01 ...L

SUBSURFACE EXPLORATION - TEST BORING LOG Boring No.

Project No,

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LAWLER , MA TUSKY 3. SKEL.L Y ENGINE::r
ATTACHMENT 2

BOTTOM PROFILES - BOWLINE POND IN THE VICINITY

OF BPGS COOLING WATER !NT AKE

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TEST FRAME OBSERVATION INFORMATIONFINE MESH BARRIER NET EVALUATION STUDY

1993 (Page 1 of 2)

TSK METER REVS

DATE TIME TEST PANEL INSIDE OUTSIDE COMMENTS

26 Apr 1600 24 A- 0000 0000 Initial deployment

1555 24 A- 0000 0000 Initial deployment

1550 35 D- 0000 0000 Initial deployment

1545 35 D- 0000 0000 Initial deployment

26 Apr 1906 24 A- Initial check

1903 24 A- 545 5620 Initial check

1859 35 D- 3600 5400 Initial check

1855 35 D- 775 5520 Initial check

27 Apr 0918 24 A- 200 28020 Very light debris and a few Gammarus

0913 24 A- 5930 30205 Very light debris and a few Gammarus

0904 35 D- 3060 33155 Very light debris and a few Gammarus

0858 35 D- 810 15300 A few Gammarus small pieces of weed-debris light

28 Apr 0822 24 A- 310 40675 A few Gammarus, debris light

0818 24 A- 1320 34770 A few Gammarus, debris light

0810 35 D- 17670 31185 A few Gammarus, debris light

0804 35 D- 2855 A few Gammarus, debris light

29 Apr 1243 24 A- 47315 A few Gammarus

1239 24 A- 40845 A few Gammarus, few pieces of weed

1236 35 D- 49555 A few Gammarus, small amount of aquatic

vegetation.

1233 35 D- 1325 A few Gammarus, small amount of vegetation

30 Apr 1626 24 A- 45640 Few Gammarus and light debris

1623 24 A- 800 38785 Few Gammarus and light debris

1618 35 D- 19930 48155 Few Gammarus and light debris

1614 35 D. 520 Few Gammarus with bits of detritus and leaves

3 May 0730 24 A- 375 I 06460 Gammarus, little debris

0726 24 A- 225 87830 Gammarus, little debris

0722 35 D- 53150 104450 Gammarus, small quantity of detritus

0718 35 D- 2360 Gammarus, leaves, bits of detritus
TEST FRAME OBSERVATION INFORMATION -

FINE MESH BARRIER NET EVALUATION STUDY

1993 (Page 2 of 2)

DATE

TSK METER REVS

TIME TEST PANEL INSIDE OurSIDE COMMENTS

4 May 1 oo5 24 A- 285 43595 Gammnrus, light debris

1 oo3 24 A- 3535 34670 Gammnrus, light debris

1Ooo 35 D- 23210 44620 Gammnrus, a few leaves

0956 35 D- 2720 Gammarus, a few leaves, and light debris

6 May 0710 24 A- 31435 Gammnrus very light debris

0712 24 A- 3330 64195 Gammnrus, light debris

0715 35 D- 19380 77525 Light debris

0707 35 D- 940 Small quantity of detritus

11 May 0916 24 A- Few leaves and Gammnrus, small bits of aquatic

vegetation, some fine sediment

0917 24 A- Few leaves and Gammarus, small bits of aquatic

vegetation, some fine sediment

0918 35 D- Few leaves and Gammarus, small bits of aquatic

vegetation, some fine sediment

0915 35 D- Few leaves and Gammarus small bits of aquatic

vegetation. some fine sediment

18 May 0957 24 A- Few Gammnrus, little detritus (bits of weed)

1Ooo 24 A- Little detritus (slightly heavier than 24 A-UT)

1 oo2 35 D- Debris load light, however, heavier than 24 A-UT,

small bits of weed

0954 35 D- Few Gammnrus, pieces of wood spread around net-light

25 May 09oo 24 A- Debris light

0902 24 A- Debris light

0904 35 D- Debris light

0859 35 D- Brown slimy material on mesh, light debris load

1 Jun 1039 24 A- Light debris

1040 24 A- Light debris

1042 35 D- Light debris

1038 35 D- Light debris

15 Jun 1039 24 A- Leaves and algae - approximately 70-75 % clogged

1042 24 A- Some leaves, brown algae - approximately 35 % clogged

1045 35 D- Leaves - brown algae - approximately 50% clogged

greater clogging at bottom of net

1030 35 D- Leaves and brown filamentous algae - approximately

60% clogged
IT ACHMENT 4

COOLING WATER INTAKE PUMP ENTRAINMENT

COLLECTION INFORMATION
BOWLINE POINT FINE MESH BARRIER NET EVALUATION STUDY

ICHTHYOPLANKTON COLLECTION INFORMATION

ENTRAINMENT PUMP SAMPLES

19-Jul-93 Unit 1 1001 10:27 36.83 I I 733. 27. 162, 923.

Unit 2

2O-Jul-93 Unit 1 1006 15:14 32.17 I 31. 31. 62.

Unit 2

21-Jul-93 Unit 1 1009 16:55 35.26 I 28.4 28.4

Unit 2

22-Jul-93 Unit 1 1010 16:14 35.88 I

Unit 2

23-Jul-93 Unit 1 1015 08:04 34,07 I 146. 29.4 176.

Unit 2Unit 1 1019 11:57 34.07 I 29. 29.4

Unit 2Unit 1 1023 14:50 35.39 I 28. 28. 56,

Unit 2

26-Jul-93 Unit 1 1030 11:21 35.86 I 27. 27.

Unit 2Unit 1 1034 13:20 34.07 I 29.4 29.4Unit 2Unit 1 1037 15:16 34,07 I

Unit 2 

27-Jul-93 Unit 1 1039 08:35 34,07 I 29.4 29.4

Unit 2 Unit 1 1043 11:17 34,07 I 29. 29.4Unit 2 Unit 1 1049 14:10 34,07 I

Unit 2 

28-Jul-93 Unit 1 1052 08:22 34. 29.4 58. 88.

Unit 2 1053 09:16 34,

Unit 1 1061 12:52 34.

Unit 2 1057 11:58 34.Unit 1 1063 14:31 34, 29.4 29.4

Unit 2 1066 15:15 34.

Unit 1 1071 10:22 34. 29.4 29.4

Unit 2 1067 08:35 34.

Unit 1 1072 11:37 34.

Unit 2 1076 12:25 31.

Unit 1 1079 14:50 34.

Unit 2 1081 15:50 22,

3O-Jul-93 Unit 1 1082 08:15 34. 234, 29.4 264,

Unit 2 1086 08:59 34.Unit 1 1090 11:50 34.

Unit 2 1087 11:07 34,
BOWLINE POINT FINE MESH BARRIER NET EVALUATION STUDY

ICHTHYOPLANKTON COLLECTION INFORMATION

ENTRAINMENT PUMP SAMPLES

Unit 1 Unit 2 1092

02-Aug-93 Unit 1 1100 Unit 2 1096

Unit 1 1102Unit 2 1105Unit 1 1110Unit 2 1106

03-Aug-93 Unit 1 1114 Unit 2 1111

Unit 1 1118Unit 2 1120Unit 1 1125Unit 2 1122

04-Aug-93 Unit 1 1130 Unit 2 1127

05-Aug-93 Unit 1 1135 Unit 2 1133

Unit 1 1139Unit 2 1140

06-Aug-93 Unit 1 1141 Unit 2 1142

Unit 1 1145Unit 2 

09-Aug-93 Unit 1 Unit 2 1147

Unit 1 Unit 2 1151

BN-OUT 1152

Unit 1 Unit 2 1157

BN-OUT 1156

1D-Aug-93 Unit 1 

Unit 2 1162

BN-OUT 1161

Unit 1 Unit 2 1167

BN-OUT 1166

Unit 1 

Unit 2 1172

BN-OUT 1171

11-Aug-93 Unit 1 

14:02 34.

09:30 34.08:50 34.

12:07 34.12:48 34.15:27 34.14:40 34, 08:55 34, 08:13 34.11 :38 34.12:16 34.15:20 34.14:42 34.16:30 22.15:08 34.

10:30 34.

09:51 34.

14:37 34.15:14 34.

09:28 30.

11:02 . 30.14:22 30.

08:10 34.

11:35 34,12:35 34.

14:56 34.14:56 34,

09:43 34.

09:38 34.

12:07 34.12:00 34.

14:43 34.14:35 34.

29.4 29.4
.,.

BOWLINE POINT FINE MESH BARRIER NET EVALUATION STUDY

ICHTHYOPLANKTON COLLECTION INFORMATION

ENTRAINMENT PUMP SAMPLES

Unit 2 1176 09:43 34.

BN-OUT 1177 09:50 34,

Unit 1Unit 2 1182 12:18 34,

BN-OUT 1181 12:11 34.

Unit 1Unit 2 1187 14:39 34.

BN-OUT 1186 14:30 34.

12-Aug- Unit 1

Unit 2 1194 13:13 36.

BN-OUT 1195 13:13 34,

Unit 1Unit 2 1199 15:33 39,

BN-OUT 1200 15:33 34.

13-Aug- Unit 1

Unit 2 1204 09:44 36.

BN-OUT 1205 09:44 34,

Unit 1

Unit 2 1209 12:14 36.

BN-OUT 1210 12:14 34.

Unit 1Unit 2 1214 14:40 36.

BN-OUT 1215 14:40 34.

16-Aug- Unit 1

Unit 2 1216 08:35 34.

BN-OUT 1217 08:40 34,

Unit 1Unit 2 1221 13:30 34.

BN-OUT 1222 13:37 34.

NA = Not analyzedBN-QUT = Pump sample collected outside of the barrier net.
...

t:C

(j Z

1-3

t/)

t""t/)

3::t:T'J
BOWLINE POINT FINE MESH BARRIER NET EVALUATION STUDY

ICHTHYOPLANKTON COLLECTION INFORMATION

5M PLANKTON NET SAMPLES

NORTH 1064 14:39 27.

SOUTH 1062 14:30 31.

INSIDE 1065 14:58 34.

29-Jul- NORTH 1069 08:50 28.

SOUTH 1068 08:42 33.

INSIDE 1070 09:12 34.

NORTH 1074 12:00 30.

SOUTH 1073 11 :52 35.

INSIDE 1075 12:18 34.

NORTH 1078 14:40 27.SOUTH 1077 14:34 31.71

INSIDE 1080 15:01 31.41

3O-Jul- NORTH 1084 08:29 28,

SOUTH 1083 08:23 32,

INSIDE 1085 08:54 32,

NORTH 1089 11 :31 26.SOUTH 1088 11 :24 34.

INSIDE 1091 11:56 32.

NORTH 1094 14:18 28,SOUTH 1093 14:13 34,

INSIDE 1095 14:37 33,

02-Aug- NORTH 1098 09:07 28.

SOUTH 1097 09:00 31.

INSIDE 1099 09:29 35,

NORTH 1103 12:09 25.SOUTH 1101 12:04 35.

INSIDE 1104 12:28 35.

NORTH 1108 14:56 27.

SOUTH 1107 14:51 38.

INSIDE 1109 15:13 33.

03-Aug- NORTH 1115 09:00 14,

SOUTH 1113 08:54 31.

INSIDE 1112 08:39 30.

NORTH 1117 11:35 27,SOUTH 1116 11 :31 35,

INSIDE 1119 11 :52 30.

NORTH 1124 14:58 26,

SOUTH 1123 14:53 33,

INSIDE 1121 14:35 31.41

04-Aug- NORTH 1129 15:16 26.

SOUTH 1128 15:10 32,

INSIDE 1126 14:55 31.71

05-Aug- NORTH 1132 09:30 27,

SOUTH 1131 09:25 34,

INSIDE 1134 10:01 27,

32. 32.

35.29,

191,

310.

92,92,

111.

31.069.87.

105,

96,83.

29.

31.

35.29,

159.

310,

61.961.

111.

31.

31.0

30.

31.0

69.87.

105.

64.

83,

32.

29.

31.
BOWLINE POINT FINE MESH BARRIER NET EVALUATION STUDY

ICHTHYOPLANKTON COLLECTION INFORMATION

5M PLANKTON NET SAMPLES

NORTH 1138 13:43 30.

SOUTH 1137 13:40 33.

INSIDE 1136 13:27 26,

06-Aug- NORTH 1144 14:14 24,

SOUTH 1143 14:10 28,

INSIDE 1146 14:31 30.

09-Aug- NORTH 1149 09:14 25.

SOUTH 1148 09:08 27.

INSIDE 1150 09:31 31.41

NORTH 1155 14:20 27.

SOUTH 1154 14:16 31.41

INSIDE 1153 14:06 32.

1160 08:27 33. 10-Aug- NORTH

SOUTH 1159 08:22 34.

INSIDE 1158 08:10 31.41

NORTH 1165 11:30 30,SOUTH 1164 11 :25 32.

INSIDE 1163 11 :14 32.

NORTH 1170 14:00 29,SOUTH 1169 13:55 35,

INSIDE 1168 13:42 34,

11-Aug- NORTH 1175 08:48 25.

SOUTH 1174 08:41 30.

INSIDE 1173 08:27 33.

NORTH 1180 11:30 25.SOUTH 1179 11 :25 31.

INSIDE 1178 11 :13 38.

NORTH 1185 13:57 28.

SOUTH 1184 13:53 32.

INSIDE 1183 13:42 37.

12-Aug- NORTH 1189 08:30 25.

SOUTH 1188 08:24 31.

INSIDE 1190 08:54 32.

NORTH 1196 12:18 26.

SOUTH 1193 12:14 30.

INSIDE 1191 12:01 31,

NORTH 1197 14:51 28.SOUTH 1196 14:47 29.

INSIDE 1198 15:05 28.

13-Aug- NORTH 1202 08:48 27.

SOUTH 1201 08:44 32.

INSIDE 1203 09:03 32.

NORTH 1208 11:43 25,

SOUTH 1207 11:38 29,

INSIDE 1206 11 :25 32,

31. 31.

30.4 30.4
t:I:1

trj

I:'

trj

..,

:r=3::

tr10'\
BOWLINE POINT FINE MESH BARRIER NET EVALUATION STUDY

ICHTHYOPLANKTON COLLECTION INFORMATION

5M PLANKTON NET SAMPLES

,~!I. ,'" ::mmm::#;~:m;W:#WmN

::::::JI!.\'ilf.II~I; 111111~11111

NORTH 1213 13:54 24.

SOUTH 1212 13:49 29.

INSIDE 1211 13:38 31.

16-Aug- NORTH 1219 12:11 27.

SOUTH 1218 12:04 32.47

INSIDE 1220 12:26 32.

NS = No SampleNA = Not Analyzed

36.4 36.4
WATER QUALITY INFORMATION

BOWLINE POINT FINE MESH BARRIER NET EVALUATION PROGRAM-1993

SPECIFIC DISSOLVED SECCHI

WATER TEMP CONDUCTANCE SALINITY OXYGEN DISK

DATE TIME DEPTH Celsius umhos/cm 25 C (ppt) (mgfl

MID 25. 0500

BOT 25. 11000

20 JUL 

21 JUL NS

22 JUL 1709 SUR 25. 10080

MID 24. 10100

BOT 24. 10100

23 JUL 0949 SUR 24. 11000 90.

MID 24. 11000

BOT 24. 10000

1230 SUR 24. 11100 83.

MID 24. 11100

BOT 24. 11100

1528 SUR 25. 10000 80.

MID 24. 10900

BOT 24. 10900

26 JUL 0912 SUR 24. 9800 81.

MID 24. 9900

BOT 24. 0200

1300 SUR 25. 10000 76.

MID 25. 0200

BOT 24. 10200

1536 SUR 25. 10000 7.4 76.

MID 25. 0000

BOT 24. 10000

27 JUL 0935 SUR 24. 10000 88.

MID 24. 0200

BOT 24. 0200

1145 SUR 25. 9900 78.
WATER QUALITY INFORMATION

BOWLINE POINT FINE MESH BARRIER NET EVALUATION PROGRAM-1993

SPECIFIC DISSOLVED SECCHI

WATER CONDUCTANCE SALI N!TV OXYGEN DISK

DATE TIME DEPTH umhos/cm 25C

MID 24. 0000

BOT 24. 10000

1440 SUR 24. 10000 83.

MID 25, 10000

BOT 24. 0200

28 JUL 1040 SUR 25. 9500 86.4

MID 25. 9500

BOT 25. 10000 6.4

1240 SUR 26. 9800 7.4 76.

MID 26. 9800

BOT 24. 10000

1505 SUR 26. 9500 81.

MID 26. 9500

BOT 25, 9800

29 JUL 0925 SUR 26. 9000 81.

MID 25. 9200

BOT 25. 9600 5.4

1225 SUR 26, 9000 88.

MID 26. 9000 7.4

BOT 25. 9500

1515 SUR 27. 9100 81.

MID 26. 9400

BOT 26. 9400 7.4

30 JUL 0905 SUR 26. 9200 8.4 96.

MID 25. 9600

BOT 25, 10000

1125 SUR 26. 9200 95.

MID 25. 9300

BOT 25. 9800

1445 SUR 26. 9300 86.4
WATER QUALITY INFORMATION

BOWLINE POINT FINE MESH BARRIER NET EVALUATION PROGRAM-1993

SPECIFIC DISSOLVED SECCHI

WATER CONDUCTANCE SALI N ITY OXYGEN DISK

DATE TIME DEPTH umhos/cm 25C m /I

MID 25. 9300

BOT 25. 9600

2AUG 0940 SUR 25. 9000 73.

MID 25. 9200

BOT 25. 9400

1235 SUR 26. 9100 86.4

MID 26. 9000 7.4

BOT 25. 9500

1525 SUR 25. 9200 8.4 73.

MID 25. 9200 7.4

BOT 25. 9500

3AUG 0910 SUR -26. 9200 73.

MID 26. 9200

BOT 25. 9200

1200 SUR 26, 9000 7.4 88.

MID 26. 9200

BOT 26. 9300

1445 SUR 27. 9000 88.

MID 26. 9100

BOT 25. 9800

4AUG 1525 SUR 26. 8200 82.

MID 26. 8500

BOT 25. 8950

5AUG 100 SUR 26. 8500 6.4 114.

MID 25. 8600 6.4

BOT 25. 8800

1335 SUR 26. 8500 121.

MID 26. 8500

BOT 26. 8500

6AUG 143 SUR 25. 8000 111.
WATER QUALITY INFORMATION

BOWLINE POINT FINE MESH BARRIER NET EVALUATION PROGRAM-1993

SPECIFIC DISSOLVED SECCHI

WATER CONDUCTANCE SALINITY OXYGEN DISK

DATE TIME DEPTH umhos/cm 25C m /I

MID 25. 8200 7.4

BOT 25. 8300

9AUG 0935 SUR 25. 7500 88.

MID 25. 8000

BOT 25. 8000

1430 SUR 25, 7500 86.4

MID 25. 7500 7.4

BOT 25. 8000

10AU 0830 SUR 25. 7100 106.

MID 25. 7100

BOT 25. 7800

1140 SUR 25. 7100 88.

MID 25. 7100

BOT 25. 7800

1410 SUR 26. 7700 73.

MID 25. 7800

BOT 25. 7900

11 AU 0900 SUR 25. 7100 104.

MID 25. 7100

BOT 25. 8000

1145 SUR 25. 7100 81.

MID 25. 7100

BOT 25. 7500

1410 SUR 25. 7200 71.

MID 25. 7100 7.4

BOT 25. 8000

12AU 0900 SUR 24. 5500 96.

MID 24. 6900

BOT 24. 7200

1225 SUR 24. 7000 96.
WATER QUALITY INFORMATION

BOWLINE POINT FINE MESH BARRIER NET EVALUATION PROGRAM-1993

SPECIFIC DISSOLVED SECCHI

WATER CONDUCTANCE SALINITY OXYGEN DISK

DATE TIME DEPTH umhos/em 25C

MID 24. 7000 7.4

BOT 24. 7100

1510 SUR 24. 7000 88.

MID 24. 7000

BOT 24. 7000

13 AU 091 SUR 24. 7000 106.

MID 24. 7000 7.4

BOT 24. 7100

1155 SUR 25. 7200 96.

MID 24. 7200

BOT 24. 7800

1405 SUR 26. 7200 94.

MID 25. 7300

BOT 24. 7500

16AU 1215 SUR 26. 8400 88.

MID 25. 8900

BOT 25. 9100

18AU 1150 SUR 25. 9000 127.

MID 25. 9500

BOT 24, 9500
IT ACHMENT 7

TOTAL LENGTH - BODY DEPTH

MEASUREMENTS FOR BAY ANCHOVY
LENGTII - DEPTH RELATIONSHIP FOR BAY ANCHOVY

FISH LENGTII DEPTIi FISH LENGTII D EPTH

NUMBER (mm) (mm) NUMBER (mm) (mm)

10.

12. 1.2

10. 1.0

12. 1.2

10.

12, 1.1

10.

11.3

8.4

10.

100

101 12. 1.2

10, 102

10, 103

104

10S

106

107

12. 1.2 108

109

10. 110

III

11.2 1.0 112 10.

113 10,

114

10. liS 10. 1.0

116

10. 1.0 117 10.

118

119 10.

120

121

122 10.

123

124 13, 1.3

12S 12. 1.1

11, 1.0 126

127 15. 1.5

128 22. 2.7

129

130 13. 1.2

131

132

0.3 133 l3. 1.3

134 17. 1.6
..,