F I N A L R E P O R T

ADDENDUM TO

EVALUATION OF THE SCATTERGOOD

GENERATING STATION WITH RESPECT TO

THE CLEAN WATER ACT

SECTION 316(b) REQUIREMENTS

PROVIDING A CURRENT ASSESSMENT OF

ALTERNATIVE TECHNOLOGIES AND

OPERATIONAL MEASURES

Prepared by

Alden Research Laboratory, Inc.

EPRI

MBC Applied Environmental Sciences

Tenera Environmental, Inc.

URS Corporation

for

City of Los Angeles Department of Water and Power

111 N. Hope Street

Los Angeles, California 90012-2607

May 3, 2007
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

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TABLE OF CONTENTS

SECTION PAGE

1.0 Introduction ....................................................................................... 1-1

2.0 Additional Information Currently Available ................................... 2-1

2.1 ADDITIONAL TECHNOLOGIES.................................................................................2-1

2.2 IMPINGEMENT MORTALITY AND ENTRAINMENT CHARACTERIZATION ...................2-2

2.3 COSTS ...................................................................................................................2-2

2.4 SECOND CIRCUIT COURT DECISION .......................................................................2-3

3.0 Entrainment Reduction Options....................................................... 3-1

3.1 FINE-MESH MODIFIED TRAVELING SCREENS..........................................................3-1

3.2 NARROW-SLOT CYLINDRICAL WEDGEWIRE SCREENS ............................................3-3

3.3 MODULAR INCLINED SCREENS ..............................................................................3-3

3.4 FLOW REDUCTION .................................................................................................3-4

3.5 CLOSED-CYCLE COOLING ......................................................................................3-5

3.6 ADDITIONAL TECHNOLOGIES.................................................................................3-5

4.0 Impingement Mortality Reduction Options..................................... 4-1

4.1 COARSE-MESH MODIFIED TRAVELING SCREENS ....................................................4-1

4.2 WIDE-SLOT CYLINDRICAL WEDGEWIRE SCREENS ..................................................4-1

4.3 COARSE-MESH BARRIER NET.................................................................................4-2

4.4 MODULAR INCLINED SCREENS ..............................................................................4-2

4.5 FLOW REDUCTION .................................................................................................4-2

4.6 CLOSED-CYCLE COOLING.......................................................................................4-3

4.7 ADDITIONAL TECHNOLOGIES.................................................................................4-3

5.0 Cost Update........................................................................................ 5-1

6.0 Data Gaps and Uncertainties ............................................................ 6-1

7.0 Conclusions ........................................................................................ 7-1
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

ii

LIST OF TABLES

TABLE 2-1. PERTINENT PROJECT DATA (REVISED TABLE 2-1 FROM THE INITIAL REPORT)..............2-5

TABLE 2-2. COMPARISON OF PERCENT COMPOSITION OF ENTRAINED LARVAE LENGTHS

COLLECTED AT SGS ................................................................................................................2-7

TABLE 2-3. INITIAL SCREENING OF FISH PROTECTION ALTERNATIVES AT SGS (REVISED

TABLE 3-1 FROM THE INITIAL EVALUATION) ...........................................................................2-8

TABLE 3-1. PREDICTED HEAD CAPSULE DEPTH (HCD) OF REPRESENTATIVE ENTRAINED

LARVAE COLLECTED AT SGS ..................................................................................................3-2

TABLE 5-1. ALDEN’S APPRAISAL LEVEL COSTS OF EVALUATED ALTERNATIVES............................5-2

TABLE 6-1. DATA GAPS AND UNCERTAINTIES FOR ALTERNATIVES .................................................6-2

TABLE B-1. QUALITATIVE RANKING, WITH 1 BEING LOWEST AND 5 BEING HIGHEST OF

POTENTIAL RESTORATION PROJECTS FOR OFFSETTING SCATTERGOOD GENERATING

STATION IM&E LOSSES............................................................................................................12

LIST OF ATTACHMENTS

ATTACHMENT A - SUMMARY OF 2004 EVALUATION OF SGS

ATTACHMENT B - LADWP RESTORATION OPTIONS

ATTACHMENT C - FLOW CALCULATIONS

ATTACHMENT D - FISH MORPHPMETRY AND SCREEN MESH HEADLOSS

ATTACHMENT E - USE OF RECLAIMED WATER AT SGS
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

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LIST OF ACRONYMS

AFB Aquatic Filter Barrier

BTA Best Technology Available

cfs cubic feet per second

CWIS cooling water intake system

DOC Debris and Organism Collection

EPA U.S. Environmental Protection Agency

EPRI Electric Power Research Institute

ft/sec feet per second

FPS Fish Protection System

gpm gallons per minute

HCD head capsule depth

HGS Harbor Generating Station

ILAH Inner Los Angeles Harbor

IM&E Impingement Mortality and Entrainment

LADWP Los Angeles Department of Water and Power

MIS Modular Inclined Screens

mm millimeter

MW megawatts

MWh megawatt hour

NOAA National Oceanic and Atmospheric Administration

O&M Operating and Maintenance

VSD Variable Speed Drives
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

1-1

1.0 INTRODUCTION

In December 2004, Alden Research Laboratory, Inc. (Alden), under contract to the Electric Power

Research Institute (EPRI), developed a report entitled“EvaluationoftheScattergood Generating

StationwithrespecttotheEnvironmentalProtectionAgency’s316(b)RulesforExistingFacilities”

for the Los Angeles Department of Water and Power (LADWP). This report provided an assessment

of the universe of technologies available for consideration for fish protection at steam generating

stations and resulted in a limited number of technologies and operational measures that were

considered appropriate for the Scattergood Generating Station (SGS). A summary of the results of

the 2004 evaluation is provided in Attachment A.

SGS is subject to both the impingement mortality and entrainment (IM&E) reduction performance

standards. In addition to the entrainment reduction technologies, which also generally provide a

benefit for impingeable-sized organisms, the original assessment also included impingement only

alternatives. This distinction will be maintained in this report.

The technologies evaluated in the initial preliminary investigation fall into four categories: physical

barriers, collection systems, diversion systems, and behavioral barriers. Diversion systems and

behavioral barriers require the ability of the organisms to swim away. Entrainable organisms lack the

sustained swimming ability to respond effectively to these systems; therefore, they were eliminated

from consideration to meet the entrainment reduction standard. Three technologies (i.e., cylindrical

wedgewire screens, fine-mesh traveling screens, and modular inclined screens) are considered as

entrainment and entrainment/impingement reducing options at SGS. The Cooling Water Intake

System (CWIS) location and hydraulic conditions at SGS make this site unsuitable for wedgewire

screens to be installed in the conventional manner (i.e., offshore location may prevent use of an air

backwash system).

As discussed below, more current information allows for re-consideration of technologies and

operational measures. This report will serve as an Addendum to the 2004 report. The 2004

evaluation also included a discussion of restoration projects. An update to the restoration evaluation

is provided in Attachment B. To develop this Addendum, Alden consulted with EPRI, MBC Applied

Environmental (MBC), Tenera Environmental, Inc. (Tenera), and URS Corporation (URS).
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

2-1

2.0 ADDITIONAL INFORMATION CURRENTLY AVAILABLE

ThefollowingnewinformationhasbeenassessedasitrelatestoAlden’soriginalevaluation:

 Additional technologies have become available;

 LADWP has completed a one-year IM&E study;

 Costs can be updated to 2006 values; and

 The Second Circuit Court (Court) issued a decision (Decision) on various components of the

Phase II Rule.

Table 2-1 is a revised and updated version of Table 2-1 in the initial report. This table reflects

updated knowledge of the facility. Also, velocity calculations are provided in Attachment C.

A discussion of the impacts of these new data on the alternatives previously evaluated and additional

alternatives that are available for SGS is presented in the following sections.

2.1 ADDITIONAL TECHNOLOGIES

Inthe2004report,therewerefourtechnologiescharacterizedas“emergingtechnologies”:

 Beaudrey’sFishProtection System (FPS);

 Filtrex Filter Candles;

 Debris and Organism Collection (DOC) system; and

 Geiger’sMulti-Disc Screening System.

Currently, the Filtrex Filter Candles have not been tested, and research on the DOC was discontinued

after limited laboratory testing. The original FPS has also not been tested. However, a variation of

the original system that utilizescircularrotatingscreenswithafish“scoop”hasbeeninstalledatone

facility and is currently being tested. Therefore, there is no new information to assess the feasibility,

cost, or effectiveness of these three technologies at this time.

The multi-disc screens with fish protection features (for impingement) have been installed at two

facilities. The first installation was at the Potomac Generating Station and was the subject of a oneyear EPRI study. The preliminary results have been positive and it appears this technology has the

potential to match the impingement mortality reduction results from Ristroph screens. In addition,

this technology provides the benefit of eliminating carryover. The second installation was in late

2006 at the Salem Generating Station on the Delaware River and no data are available at this time.

Another emerging technology with fish protection features, not available in 2004, is a plastic belt

screen manufactured by Hydrolox. These screens are lighter and potentially less costly to install and

operate than other traveling screens. The plastic belt screens are new and do not have any long-term

operational data, but pilot studies currently planned at one estuarine site on Long Island, NY should

provide useful information on biological efficacy and operational issues. Because of the material

used and way that the screen is constructed, the smallest mesh size available at this time is 1.75

millimeters (mm). Thus,thistechnologyhasthesame“limitation”astheModularInclinedScreen

(MIS) system in excluding only larger entrained organisms and, therefore, would not meet

entrainment performance standards for SGS.
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

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Two new currently available screening technologies (i.e., Hydrolox and Geiger screens) can be

consideredinthesamecategoryasRistrophscreens.Bothofthesesystemsfunctiononthe“trapand

transfer”conceptandrequirethesametypeoffishanddebris returns as Ristroph screens. The

modified traveling water screen discussions in Sections 3 and 4 apply to all three of these

technologies.

Currently an EPRI-funded laboratory study is under way to determine the survival of entrainablesized organisms impinged on fine-mesh traveling screens.

The testing is being conducted in the recently refurbished large, fish testing facility at Alden.

Modifications to this facility were made to allow for installation of three test screens the Geiger

Multi-Disc Screen (0.5 mm), a Brackett-Green through-flow screen (0.5 mm), and a Hydrolox screen

(1.0 mm).

Parameters to be evaluated include:

 Two approach velocities (0.5 and 1.0 ft/sec)

 Two durations of impingement (4 and 8 minutes)

 Two freshwater species with divergent morphologies, which allows them to be tested at the

same time.

 Three length classes

 Three treatment replicates and two handling control replicates run on each testing day.

2.2 IMPINGEMENT MORTALITY AND ENTRAINMENT CHARACTERIZATION

Although the relative contribution of the most abundant species impinged has varied from 1990

through 2003 to 2006, prominent species impinged include queenfish, topsmelt, jacksmelt, salema,

barred sand bass, white croaker, walleye surfperch, yellowfin croaker, sargo, and Pacific sardine. The

2006 impingement was dominated by Pacific sardine. This most current impingement data do not

changeAlden’sselectionofappropriatetechnologiesforconsiderationatSGS.

Entrainment data were collected in 2006. Unidentified sciaenids, northern anchovy, Paralabrax,

spp., white croaker, gobies, Engraulidae, Pacific barracuda, queenfish, California halibut, blennies,

and sanddab are abundant species entrained. The 2006 results documented that 93-100% (depending

on species) of entrained organismswere“pre-transformation”stage.Thatis,thevastmajorityof

entrained fish were less than 12 mm in length. The lengths of larvae collected in 2006 are provided in

Table 2-2.

The results of the IM&E study reportedly demonstrate that the impingement reduction standard can

be met due to the location of the intake structure and the utilization of a velocity cap. Discussions of

any impingement-related technologies and or impingement mortality reduction standards are provided

in the event that this claim is rejected by the permitting agencies.

TheseresultsdonotalterAlden’sselectionofappropriatetechnologiesforconsiderationinreducing

entrainment at SGS. As discussed in Section 3, the overall efficacy of any entrainment reduction

technology is mitigated by the predominance of such early life history stages.

2.3 COSTS

Alden has revised and updated the costs from the 2004 report to reflect current (2006) costs of

appropriate technologies. These costs are included in Table 5-1 in Section 5 of this Addendum (i.e.,
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

2-3

Table 6-3 from 2004 report). An adjustment factor of 1.121 was used to account for inflation and the

price per megawatt hour (MWh) was increased from $40/MWh to $50/MWh2. For technologies that

were evaluated further in this Addendum, the costs presented in Table 5-1 have been modified to

reflect the updated evaluations.

2.4 SECOND CIRCUIT COURT DECISION

The Court issued its Decision on the Phase II Rule on January 27, 2007. This Decision had

significant impacts on the compliance alternatives and options discussed in the 2004 report. The

major components of the Decision are:

 The Court determined that two options, use of Restoration Measures and the Cost-Benefit

Test, are unlawful and cannot be used for compliance;

 The Court remanded to U.S. Environmental Protection Agency (EPA) the determination of

Best Technology Available (BTA); and

 The Court also remanded to EPA the Cost-Cost Test and Technology Installation and

Operation Plan duetoEPA’sfailuretoprovideadequateopportunityforpublicreviewand

comment for these two provisions.

The remand of the BTA determination introduces some uncertainty in the analysis, since the nature of

the technologies and performance standards could change as a result of EPA revisions to the Rule.

One of the key issues EPA is required to address is whether or not use of wet or dry closed-cycle

cooling is BTA. The Court said EPA could consider three factors in this evaluation. The first is cost,

but only in a limited manner. To reject closed-cycle cooling from a cost standpoint, EPA must

determine that the industry cannot reasonably bear the cost of a national retrofit with these

technologies. The two other factors EPA may consider are adverse environmental impacts associated

with closed-cycle cooling and impacts to energy production and efficiency.

AsecondmajorcomponentoftheDecisionisarequirementtousethe“bestperforming”technology.

The Court determined that if EPA chose touseperformancestandardranges,afacility’sdecision

could no longer be based on which technology was most cost-effective. Rather, the“best

performing”technologyintheappropriateperformancestandardrangemustbeused.TheCourtdid

say that a lesscostlytechnologythanthe“bestperforming”technologycouldbeusedifitworksas

leastaswellasthelowendoftheperformancerangeofthe“bestperformer.”

The result of the Decision is that SGS will be limited to use of technologies and/or operational

measures for compliance. Use of the Cost-Cost Test may be available if it is proposed for public

review and comment. However, there is some risk that EPA could alter Appendix A costs and/or

implementation provisions in the revised Rule.

Subsequent to the Decision EPA has suspended the Rule. EPA did not budget for a major 316(b)

rulemaking in 2007, so it is not clear when a revised Phase II Rule would become effective. The

result is uncertainty as to when compliance will be required. EPA has reverted to issuing §316(b)

requirementson“BestProfessionalJudgment”(BPJ)basis. This was the approach EPA used prior to

promulgationofthePhaseIIRule.GivenCalifornia’sadvocacyon316(b)issues,thishaslittleeffect

1 Based on consumer price index from 2002 through 2006.

2 Based on average annual day ahead prices for 2006 using SP-15 CAISO real time data.
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

2-4

onLADWP’sfacilities.The suspension of the schedule allows additional time to conduct pilot

studiestoidentifythe“bestperforming”technologyforSGS.

As in 2004, fish protection technologies were considered to have potential for application at SGS if:

 The technology has proven biological effectiveness;

 The technology is available and does not require further engineering development; and

 The technology has engineering and/or biological advantages over the other technologies we

evaluated.

Table 2-3 is a revision to Table 3-1 from the initial evaluation.
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

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TABLE 2-1. PERTINENT PROJECT DATA (REVISED TABLE 2-1 FROM THE INITIAL REPORT)

Location

Los Angeles, California

Latitude: N 33o 54’59’’

Longitude: W118o26’08’’

Waterbody: Pacific Ocean

Waterbody: ocean (near-shore zone)

NPDES permit expiration date: May 10, 2005

Estimated project intake flow

Plant design: 766.5 cfs (344,000 gpm)

Units 1&2: 173.8 cfs (78,000 gpm) (each unit)

Unit 3: 418.8 cfs (188,000 gpm)

Intake velocities

Horizontal current at cap: 1.5 ft/sec

Intake pipe: 6.8 ft/sec

Traveling screens:

Units 1&2: 0.6 ft/sec

Unit 3: 0.7 ft/sec

Water Level

Elevations

Mean lower low water: 0.0 ft

Mean higher high water: 7.5 ft

Water depths: (around offshore intake)

Maximum: approx 33 ft

Minimum: approx 26 ft

Normal: approx 30 ft

Other information: all elevations refer to mean sea level

Project Structures

Offshore intake structure

Type: offshore intake

Location: 1,600 ft offshore (near-shore zone)

Top of cap: El. -11.0 ft

Cap height above intake: 5 ft

Cap radius: 16.3 ft

Intake invert: El. -17.5 ft

Intake pipe material: concrete

Intake riser pipe diameter: 17.5 ft (inside diameter)

Intake pipe diameter: 12 ft

Intake pipe length: 2,100 ft

Pipe invert: El. -44.0 ft inlet

Mammal exclusion barrier: none

Onshore intake structure

Inlet Chamber: 60arc, 68.8 ft radius

Length: 138 ft

Invert: El. -23.5 ft

Pump bays: 8

Bay width:

Units 1 & 2: 8.2ft

Unit 3: 9.0 ft
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

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Design: 2 halves (2 pumps each for units 1 &2, 4 pumps for unit 3)

Trash racks

Location: end of inlet chamber

Number: 8 (6 ft wide 35.5 ft deep)

Width: 6 ft

Top: El. 12.0 ft

Material: 3/8 in. x 4 in. steel bars

Bar spacing: 5 in. on center

Traveling water screens

Location: 22 ft downstream of trash racks

Number: 8

Screen Width: 6 ft

Top: El 12.0 ft

Rotation speeds: 10-20 ft/min

Mesh size and geometry: 3/8in x 3/4in rectangular openings

Spray nozzle configuration: spray nozzles spray front and back

Volume: 1,500 gpm

Operation: once every eight hour shift

Fish return (trough/ pipes): debris trough discharges into Debris Basket Pits

Trough configuration: two troughs leading to discharge pipe

Circulating water pumps

Number of pumps: 8 (2 each for Units 1&2, 4 for Unit 3)

Type of pumps: vertical, mixed flow

Flow per pump:

Units 1&2: 86.9 cfs (39,000 gpm)

Unit 3: 104.7 cfs (47,000 gpm)

Total flow: 766.5 cfs (344,000 gpm)

Cooling water discharge

Location: 1,200 ft offshore, 400ft away from the intake

Depth: 27 ft

Discharge pipe: 12 ft (inside diameter)

Type: 7.5 ft diameter open vertical riser pipe

Power Generation

Fuel Type:

Units 1–3: gas/oil

Plant output: (capacity)

Units 1 & 2: 179 MW

Unit 3: 460 MW

Plant design total: 818 MW

Operating mode: peaking

Plant capacity factor: 25% (2000-2004)

Unit 1: 25%

Unit 2: 31%

Unit 4: 23%

Average annual energy: 1,815,987 MWh (net)
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

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TABLE 2-2. COMPARISON OF PERCENT COMPOSITION OF ENTRAINED LARVAE LENGTHS

COLLECTED AT SGS

Percent Composition

Species

2006

Entrainment 0-5mm 5-10mm 10-15mm >15mm

Sciaenidae 18% 38% 55% --- 6%

N. anchovy 15% 4% 77% 18% 1%

Paralabrax,

ssp.

13% 55% 44% --- ---

white

croaker 12% 6% 67% 26% 1%

Gobiidae 6% 0% 85% 11% 5%

Pacific

barracuda 5% 82% 18% --- ---

References: Tenera Environmental, IM&E Characterization Study Preliminary Results 2006,

unpublished. (2007)
Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

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TABLE 2-3. INITIAL SCREENING OF FISH PROTECTION ALTERNATIVES AT SGS (REVISED TABLE 3-1 FROM THE INITIAL EVALUATION)

Concept

Biological

Effectiveness

Proven

Engineering

Alternative

Available

Advantages

Over Other

Concepts

Potential for

Application

at SGS

Comments

Behavioral Barriers

Sound yes yes no no The focus of recent fish protection studies

involving underwater sound technologies has

been on the use of new types of low and high

frequency acoustic systems that have not

previously been available for commercial use.

Sound devices are not appropriate for

entrainment reduction as the early life stages

have not yet developed hearing capabilities or

have insufficient swimming capability to avoid

entrainment.

Infrasound no yes yes no There was a general belief in the scientific

community that infrasound could represent an

effective fish repellent since there was a

physiological basis for understanding the

response of fish to particle motion. Sound

devices are not appropriate for entrainment

reduction as the early life stages have not yet

developed hearing capabilities or have

insufficient swimming capability to avoid

entrainment.

Strobe lights yes yes no no Although many studies have evaluated strobe

lights as a primary barrier system, strobes are

often evaluated as part of an integrated fish

protection and passage system that includes

other devices such as screens, narrow-spaced

bar racks, bypasses, and/or other behavioral

systems. As a secondary system, strobe lights

have the potential to incrementally increase fish

protection effectiveness. However, they are not

effective with larval fish that have little or no

motility.
Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

2-9

TABLE 2-3. INITIAL SCREENING OF FISH PROTECTION ALTERNATIVES AT SGS (REVISED TABLE 3-1 FROM THE INITIAL EVALUATION)

Concept

Biological

Effectiveness

Proven

Engineering

Alternative

Available

Advantages

Over Other

Concepts

Potential for

Application

at SGS

Comments

Mercury lights no yes yes no Response to mercury light has been shown to

be species-specific; some fish species are

attracted, others repelled, and others have

demonstrated no obvious response. However,

they are not effective with larval fish that have

little or no motility.

Chemicals no no no no Use of chemicals has been suggested, and in

some cases evaluated, as fish protection

measures. However, no practical application of

these devices has been developed, and they are

not considered available technologies for

application at CWISs.

Electric screens no yes no no Electric barriers have been shown to effectively

prevent the upstream passage of fish. However,

attempts to divert or deter the downstream

movement of fish have met with limited success.

Consequently, past evaluations have not led to

permanent applications. The potential

effectiveness of these barriers for application at

CWISs is unknown. Given their past

ineffectiveness and hazard potential, electric

screens are not considered a viable technology

for application at CWISs. As with other

behavioral barriers, electric barriers would not be

effective with larval fish that have little or no

motility.

Air bubble curtain yes yes no no These curtains generally have been ineffective

in blocking or diverting fish in a variety of field

applications. Air bubble curtains have been

evaluated at number of sites on the Great Lakes

with a variety of species. All air bubble curtains

at these sites have been removed from service.

Air bubble curtains would not be effective with

larval fish that have little or no motility.
Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

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TABLE 2-3. INITIAL SCREENING OF FISH PROTECTION ALTERNATIVES AT SGS (REVISED TABLE 3-1 FROM THE INITIAL EVALUATION)

Concept

Biological

Effectiveness

Proven

Engineering

Alternative

Available

Advantages

Over Other

Concepts

Potential for

Application

at SGS

Comments

Water jet curtain no yes no no Devices such as water jet curtains have been

suggested, and in some cases evaluated, as fish

protection measures. However, no practical

application of these devices has been

developed, and they are not considered

available technologies for application at CWISs.

Hanging chains no yes no no Devices such as hanging chains have been

suggested, and in some cases evaluated, as fish

protection measures. However, no practical

application of these devices has been

developed, and they are not considered

available technologies for application at CWISs.

In addition, they are not effective with larval fish

that have little or no motility.

Visual keys no yes no no Visual cues have been suggested, and in some

cases evaluated, as fish protection measures.

However, no practical application of these

devices has been developed, and they are not

considered available technologies for application

at CWISs.

Hybrid barriers (e.g.,

strobe light /air bubble

curtain)

no no no no No practical application of these devices has

been developed, and they are not considered

available technologies for application at CWISs.

In addition, they are not effective with larval fish

that have little or no motility.

Physical Barriers

Fixed screens yes yes no no As a barrier device, a fixed screen can only be

effective if there is a low through-screen velocity

and a way for fish to escape the CWIS. Finemesh devices would be required for entrainment

reduction. These early life history stages have

limited motility, which further reduces the

potential for protection for this technology.
Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

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TABLE 2-3. INITIAL SCREENING OF FISH PROTECTION ALTERNATIVES AT SGS (REVISED TABLE 3-1 FROM THE INITIAL EVALUATION)

Concept

Biological

Effectiveness

Proven

Engineering

Alternative

Available

Advantages

Over Other

Concepts

Potential for

Application

at SGS

Comments

Conventional traveling

water screens

yes yes no no As barrier devices, traveling screens cannot be

considered for protection of early life stages or

aquatic organisms that have little or no motility.

Rotary drum screens yes yes no no Installation of rotary drum screens would require

a much larger area than conventional traveling

screens because of the lower design velocity.

Barrier net yes yes no no Barrier nets can be considered a viable option

for protecting adult fish provided that relatively

low velocities (generally less than 1 feet/sec)

can be achieved and debris loading is light.

They would be ineffective with early life history

stages that have little or no motility.

Bar rack barrier yes yes no no Bar rack barriers are typically designed to have

spacing greater than 1 inch and would not

effectively prevent the entrainment of early life

stages. They may, however, effectively reduce

impingement.

Infiltration intakes yes yes no no Radial wells and artificial filter beds have been

successfully used to supply small quantities of

water. While such systems have little if any

biological impact, they have not been developed

for screening large flow volumes or for CWIS

application.

Porous dike yes yes no no Rock structures such as rock cribs and porous

dikes allow water to pass while preventing

passage of juvenile and adult fish. Their

effectiveness with larval fish is unknown.

Aquatic filter barrier

(AFB)

yes yes no no At this time, the AFB system is considered to be

experimental despite its potential biological

effectiveness. In addition, the space required for

installation of this technology is not available at

SGS.
Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

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TABLE 2-3. INITIAL SCREENING OF FISH PROTECTION ALTERNATIVES AT SGS (REVISED TABLE 3-1 FROM THE INITIAL EVALUATION)

Concept

Biological

Effectiveness

Proven

Engineering

Alternative

Available

Advantages

Over Other

Concepts

Potential for

Application

at SGS

Comments

Cylindrical wedgewire

screen intakes

yes yes yes yes Wedgewire screens have the potential to reduce

both entrainment and impingement at water

intakes. Effectiveness is based on the slot size,

through-slot velocity, and presence of an

ambient cross-current to carry organisms and

debris away. If an air compressor can be

located within a few hundred feet of the screens,

the air backwash system can be used to clean

the screens.

Collection Systems

Modified traveling

(Ristroph-type)

screens (coarse- and

fine-mesh) with fish

protection features

yes yes yes yes Modified traveling water screens continue to be

an available technology that can reduce fish

losses due to impingement and entrainment.

The primary concern with fine-mesh screens is

that they function by impinging early organism

life stages that are entrained through coarsemesh screens. Depending on species and life

stage, mortality from impingement can exceed

entrainment mortality. Biofouling potential must

also be considered.

Fish pumps yes yes no no Hidrostal and Archimedes screw pumps have

demonstrated an ability to transfer adult fish with

little or no mortality. These pumps by

themselves do not represent a technology for

protecting fish. However, when coupled with fish

bypass systems, such as angled screens and

louvers, fish pumps are biologically effective.

The effect of the pumps on larval fish would

need to be evaluated.

Diversion Systems

Louvers / angled bar

racks

yes yes no no Due to the large spacing of the louver slats,

louver systems do not protect early life stages of

fish.
Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

2-13

TABLE 2-3. INITIAL SCREENING OF FISH PROTECTION ALTERNATIVES AT SGS (REVISED TABLE 3-1 FROM THE INITIAL EVALUATION)

Concept

Biological

Effectiveness

Proven

Engineering

Alternative

Available

Advantages

Over Other

Concepts

Potential for

Application

at SGS

Comments

Angled screens (fixed

or traveling)

yes yes no no Angled screens can be considered a viable

option for protecting juvenile and adult life

stages provided that proper hydraulic conditions

can be maintained and debris can be effectively

removed. Fish eggs, larvae, and small

invertebrates would not be protected by angled

screens unless fine-mesh screening was used.

Also, as the length of screen increases, the

survival of larvae decreases. Guidance

efficiency improves as fish grow.

Angled rotary drum

screens

yes yes no no Installation of angled rotary drum screens would

requireanevenlargerareathan“conventional”

rotary drum screens.

Inclined plane screens no yes no no No advantage over MIS at SGS.

Eicher screen yes yes no no While biologically effective, the Eicher screen

was designed for penstock and pipes. There is

no advantage over an MIS at SGS.

MIS yes yes yes yes The combined results of laboratory and field

evaluations of the MIS have demonstrated that

this screen is an effective fish diversion device

that has the potential for protecting fish at water

intakes. Any consideration of the MIS for CWIS

application should be based on future largescale, prototype evaluations. Some reduction in

entrainment can be expected.

Submerged traveling

screens

no yes no no Designed for partial screening of hydroelectric

project intakes. Not applicable to SGS.
Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

2-14

TABLE 2-3. INITIAL SCREENING OF FISH PROTECTION ALTERNATIVES AT SGS (REVISED TABLE 3-1 FROM THE INITIAL EVALUATION)

Concept

Biological

Effectiveness

Proven

Engineering

Alternative

Available

Advantages

Over Other

Concepts

Potential for

Application

at SGS

Comments

Modifications to Reduce Intake Flow

Modified pump

operation

yes yes yes yes Reducing flow will reduce impingement and

entrainment. Flow reduction could be

accomplished by either turning pumps on and off

or with the installation of variable speed drives to

follow the load (see below). If SGS is operating

at or near its thermal effluent limits then units

would need to be de-rated during flow reduction.

Install variable speed

drives (VSD)

yes yes yes yes VSDs could be used at SGS to better regulate

intake flow. VSDs would allow SGS to minimize

lost generation during peak periods.

Install closed-cycle

cooling system

(mechanical, natural

draft and dry cooling

towers)

yes yes yes yes Closed-cycle cooling will reduce flow

significantly. Depending on the type of closedcycle system installed and the maximum number

of cycles-of-concentration, circulating water flow

in salt water could be reduced 73-98 percent.

Impingement and entrainment would be reduced

accordingly.
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

3-1

3.0 ENTRAINMENT REDUCTION OPTIONS

As stated previously, compliancewithEPA’sentrainmentreductionperformancestandardswillbe

difficult for marine facilities. Closed-cycle cooling or dramatic reductions in cooling water flow by

limiting station operations are extreme and costly measures. There are limited technologies that can

be considered for reducing entrainment and even more limited information of the efficacy of these

technologies with marine or estuarine species.

Fine-mesh traveling screens (e.g., Ristroph-type, Hydrolox, or Geiger) have potential for application

at SGS. There are currently no additional data available on the effectiveness of these screens in

reducing mortality of entrainable organisms.

Narrow-slot cylindrical wedgewire screens have potential for application at SGS. This technology

would reduce both impingement and entrainment to a level acceptable to the California

Environmental Protection Agency. At SGS, the screens would be mounted offshore. At this location,

a standard air backwash system would not be feasible due to the distance of the screens from the

shore. Additionally the presence of a sweeping current is not known; therefore, predicting the

effectiveness of any remote cleaning system may be difficult.

The MIS concept is a fish diversion system that guides fish into a bypass at high velocities and was

previously considered for impingement mortality reduction. The MIS would reduce entrainment of

larger organisms as well as impingement. There are currently no data available on the effectiveness

of these screens in reducing mortality of the early life history stages of the entrainable organisms for

the species present.

3.1 FINE-MESH MODIFIED TRAVELING SCREENS

Alden’soriginalevaluation reflected several issues relative to this technology that existed in 2004.

First, the approach velocity to the existing traveling screens exceeds the typical design velocity for

this technology (i.e., 0.5 feet/sec), existing approach velocities are 0.6 feet/sec at Units 1 and 2 and

0.7 feet/sec at Unit 3. As such, Alden provided costs based on an expanded screenhouse that would

accommodate the additional screens needed to reduce the approach velocity. Such an expansion

would require extensive site work and lengthy unit down time.

Having reviewed the 2006 entrainment characterization study results for SGS, Alden now believes

that survival of the earliest life history stages of fish entrained at SGS will be negligible. These life

stages dominate the entrainment numbers and, therefore, this technology would probably not meet the

entrainment reduction standard. For consistency, costs for the expanded intake option have been

provided in this Addendum. However, Alden recommends that pilot studies be conducted if LADWP

wantstoconsiderthistechnologyfurther.ThepilotstudyproposedforLADWP’sHarborGenerating

Station (which has lower velocities that SGS) would identify where survival of previously entrained

organisms starts to occur.

Organisms removed from the fine-mesh fish protection screens would have to be collected and

transported back to the ocean. The ability for fish and shellfish species and their associated life stages

to tolerate the collection and handling tend to vary considerably, which emphasizes the need for

species and life-stage-specific testing to verify survival rates. The return location would have to be

selected carefully, as there is some concern about the return of offshore organisms to the nearshore

zone. A review and comparison of two potential fish return cleaning systems is provided in

Attachment F.
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

3-2

LADWP has requested a prediction of the size mesh required to effectively exclude larval fish at

SGS. The key factor in exclusion of aquatic organisms is the maximum dimension of the organism.

Typically, head capsule depth (HCD) is selected, as it is the earliest-developed, non-compressible

body part. Unfortunately, Alden could not find adequate data on the West Coast species of interest at

SGS to develop the necessary analyses. However, adequate data have been developed for East Coast

species. Based on discussions among Alden and MBC staff, the following surrogates were used for

this assessment:

TABLE 3-1. PREDICTED HEAD CAPSULE DEPTH (HCD) OF REPRESENTATIVE

ENTRAINED LARVAE COLLECTED AT SGS

West Coast Species Length at hatch

(mm) East Coast Species Predicted HCD(mm)

Gobiidae 2.7-3.2 Naked goby 0.56

Paralabrax spp. 2.0 Atlantic menhaden 0.83

Pacific barracuda 3.8-5.0 Naked goby 0.44

White croaker 2.2-2.8 Bay anchovy 0.37

Northern anchovy 2.5-3.0 Bay anchovy 0.34

The data used for this assessment are provided in Attachment D. The above species are

representative of the most abundant larvae entrained at SGS. Based on the above information, a

nominal mesh size of 0.3 mm would be required to exclude northern anchovy yolk-sac larvae.

However, to be conservative, a 0.2 mm mesh screen was selected to exclude larvae found at SGS.

Based on information provided by screen manufacturers, a screen with a mesh/slot size of 0.2 mm can

be provided. Engineering data on the various meshes are provided in Attachment A. The following

design considerations are associated with the replacement of the existing 9.5 mm mesh screens with

0.2 mm screens:

 Increase head loss –Head loss will increase from 0.2 to 5 inches in a clean condition, and 2 to

24 inches at 50% blocked with debris.

 Screen rotation speed –Screens should be designed to operate continuously with a high

rotation speed to remove debris quickly. The debris loading will increase from current

conditions due to the smaller opening.

 Screen mesh –A 0.2 mm screen mesh will require a 1-inch backup mesh for added strength.

The wire diameter of a 0.2 mm square mesh screen is only 0.2 mm and could easily be

damaged by large debris. More frequent screen replacement is expected.

 Pre-screening –Pre-screening devices are recommended to reduce potential damage and to

reduce the debris loading at the screens. A fine-bar rack or bar screen with a 1⁄2- to 1-inch

spacing and/or a 3/8-inch traveling water screen may be required upstream of the fine-mesh

screen installation.

Finally, concern has been expressed with biofouling of the exposed (above water surface) screening

components during continuous operation of the screen. Although this may be a valid concern, an

assessment could easily be performed during a pilot study. Development of a fouling control

technology could be a component of the pilot study. However, rather than confound the biological

assessment component of the study, it may be desirable to conduct a small-scale, focused study for

evaluating biofouling conditions. Costs for this component of a pilot study have not been developed.
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

3-3

Conclusion

Fine-meshtravelingscreensaretechnicallyan“exclusiontechnology.”However,unlike narrow-slot,

wedgewire screens that depend on an air-burst cleaning system, coupled with ambient currents to

“carry”impingedfishanddebrisawayfromtheCWIS,thistechnologyutilizesa“trapandtransfer”

concept. The process of collecting organisms to assess survival imparts some level of mortality that

is difficult to ascertain in the field. Consequently, the projected efficacy of this technology will be

less than that for narrow-slot, wedgewire screens. The life stages that dominate the entrainment

numbers at SGS are such that this technology would probably not meet the entrainment reduction

standard.

3.2 NARROW-SLOT CYLINDRICAL WEDGEWIRE SCREENS

LADWP could install narrow-slot cylindrical wedgewire screen intakes at SGS to reduce fish

entrainment and impingement. Twenty-three stainless steel T-84 screens with 0.5 mm slot opening

would be required to accommodate the total facility flow. Z-alloy, a nickel-copper alloy, could be

used to reduce biofouling of the screens. This would require five additional screens and would more

than double the cost per screen. These screens would be mounted onto two intake pipes connected to

the existing pipe. The design through-screen velocity of the screens would be about 0.5 ft/sec with

clean screens. The screens would be angled so that they are parallel to the predominant currents in

the area to assure maximum sweeping flow.

Alden originally designed an air-burst backwash system to clean the screens. After discussions with

the screen manufacturer, using an air-burst system would not be practical for screens located more

than a few hundred feet from the compressor unit. As a result, alternative methods of cleaning the

screens would be necessary. One potential method is to build an offshore platform to house the

necessary air-burst equipment. A second option would use divers to regularly inspect and clean the

screens. Both these options are feasible; however, the air-burst system may be a better alternative as

it would allow remote cleaning of the screens regardless of the weather. LADWP would no longer be

able to use the existing heat treatment at SGS without modification of the wedgewire system, as the

backflow would result in the clogging of the screens from the inside.

Wedgewire screens designed with slot openings of 0.5 mm and slot velocities of 0.5 ft/sec or less

should successfully exclude from entrainment most white croaker and northern anchovy eggs (similar

to fine- mesh screens discussed above); however, a slotted wedgewire design is more conducive to

fish passage than a woven mesh of the same nominal opening size and some eggs may be entrained.

A 0.2 mm slot wedgewire screen can be provided; however, the number of screens required is

substantial (i.e., approximately 50 for SGS). A cylindrical screen with this slot width has never been

tested. The vendor also questions whether the air-burst backwash system would function effectively.

It is anticipated that macrofouling would be more of an issue with narrower slot size.

Conclusions

Narrow-slot cylindrical wedgewire screens would meet the entrainment and impingement standard.

However, due to the offshore location cleaning, the screens may be very difficult. Any cleaning

method proposed for SGS would have to be tested before full-scale application. The cost for the airburst backwash system has been removed from the total cost of the screens in the updated cost table

(Table 5-1).

3.3 MODULAR INCLINED SCREENS

Originally, the MIS was proposed as a technology to reduce impingement mortality by virtue of a 2

mm slot size (the only size for which data are available). However, in reconsidering entrainment

reduction alternatives, Alden proposed consideration of the MIS for reducing larger entrainable
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

3-4

organisms. Results of species-specific survival from pilot studies of both the fine-mesh traveling

screens and the MIS could be compared to develop overall efficacy.

All the ancillary issues associated with traveling water screens (e.g., handling and long-distance

transport of captured organisms) apply to MIS. The one exception would be elimination of the

concern with above- water biofouling as the system is submerged. The current heat treatment

practices used with the existing intake would be effective at preventing biofouling of the MIS and

intake tunnel.

Conclusion

As with the fine-mesh screen alternative, the projected efficacy of this technology will be less than

that for narrow-slot, wedgewire screens. However, depending on the ultimate efficacy for the finemesh screens, this alternative may be as effective as the other fine-mesh screen options. Alden does

not believe the MIS will meet the entrainment reduction standard. The results of the pilot study will

remove this uncertainty. The ultimate cost of the systems would dictate the technology selection.

3.4 FLOW REDUCTION

The potential use of this option is contingent upon the diel and seasonal densities of entrainable life

stages when operation of cooling water pumps could be reduced. The results of the seasonal and diel

variations for entrained organisms from the 2006 IM&E studies are not available at this time. If

results demonstrate that there are no substantial day/night differences, and entrainment is not

concentrated on a seasonal basis, targeted flow reductions during periods of high entrainment would

not be effective. Tenera and MBC are in the process of completing the entrainment study sample

processing and results should be available for generation analysis in the second quarter of 2007.

There are two approaches that could be used to reduce cooling water flow. The first is strictly

operational by curtailing use of one or more existing pumps on a diel or seasonal basis; the second

would be to retrofit pumps with variable speed drives (VSDs). If SGS is operating near its thermal

limits, shutting down circulating water pumps would result in a reduction in generation. The VSDs

would allow much finer control of flow reductions, while ensuring adequate flow to meet heat rate

and generation needs. Also, the question of whether design or actual flow can be used for the

calculation baseline needs to be considered. If the calculation baseline is based on design flow, this

option could be especially attractive for SGS. Regardless, it is unlikely that flow could be reduced

sufficiently to meet the current performance standard range.

If LADWP were to install VSDs on the circulating water pumps, a detailed, design review of

condensers, circulating water pumps, motors, and piping would need to be conducted to identify

potential issues associated with VSDs. Some key operational issues that would need to be addressed

are: unbalanced pump operation if a VSD is placed on only one pump per unit, loss of pressure in the

condenser waterboxes, vibration of the pumps at lower speeds, and potential to burn out the existing

motors. This review will further identify the limitations that may exist and provide recommendations

for each unit upgrade. The cost to install VSDs on all the circulating water pumps is included in the

cost section. The following upgrades are not included in the cost estimate, but would be required

prior to installing VSDs:

1. Installation of a back-pressure valve on the condenser discharge;

2. Installation of pump discharge valves;

3. New circulating water pumps; and

4. New pump motors.
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

3-5

Conclusion

Consideration of flow reduction remains a possible alternative. Typically, flow reductions need to be

discussed with Corporate Power Supply. Assessment of general trends in load demand can predict

periods where running at reduced loads or placing a unit(s) on standby would not affect reliability of

the plant. These flow reductions would result in some flow reduction credit. During periods of high

demand and high water temperatures, reducing flow may result in the need to de-rate the unit(s) to

maintain thermal discharge limits. Use of VSDs could be considered to better control flow reductions

and minimize lost generation. Costs have been included in this Addendum (see Table 5-1).

Regardless, this option by itself would not likely meet the entrainment reduction standard.

3.5 CLOSED-CYCLE COOLING

Closed-cycle cooling was assessed on a cursory level in the 2004 report. LADWP is participating in

the closed-cycle cooling retrofit cost evaluation study. The results of this evaluation will identify the

economic penalties associated with this option. It is also important to consider several options for use

of closed-cycle cooling. There is the potential that, when considering revisions to the Rule, EPA

could determine that use of wet or dry closed-cycle cooling is BTA. There are significant arguments

to be made that the cost of a national retrofit cannot be borne by industry. However, if EPA identified

closed-cycle cooling as BTA, itwouldbeconsideredthe“bestperforming”technology.Underthis

scenario, the Cost-Cost test (after re-proposal for review and comment) could still determine that

closed-cycle cooling has a cost significantly greater than the cost estimated by EPA.

Conclusion

Closed-cycle cooling will meet all performance standards, but whether or not closed-cycle cooling

will be required to meet the standard is not known at this time. Cooling towers would have the

highest overall capital and operating & maintenance (O&M) cost of all of the alternatives.

3.6 ADDITIONAL TECHNOLOGIES

Since the initial investigation in 2004, Alden has identified one other potential method SGS could use

to come into compliance. This option would use the reclaimed water from the Hyperion Wastewater

Treatment Facility (Hyperion) as the source for circulating water. Hyperion abuts SGS property and

can provide secondary treatment for up to 450 million gallons per day (MGD)

3

of wastewater; on

average, Hyperion treats about 362 MGD of wastewater4. This flow is sufficient to provide all the

circulating water needs for Unit 3 and some of the water for Units 1 or 2. If the water is used only for

Unit 3, it would result in a 55% reduction in flow from the current design flow. If the entire 362

MGD are used at SGS, it would result in a 73% flow reduction. The water from Hyperion could also

be used to provide made-up water for cooling towers. Potential uses, drawbacks, and appraisal-level

costs for using reclaimed water are examined further in Attachment F.

Conclusion

Either variation using the reclaimed water could significantly reduce circulating water flow and

therefore, entrainment. Depending on the how baseline is defined at SGS, using reclaimed water for

Unit 3 only may be able to meet the previous entrainment reduction standard. The ability of these

options to meet either the final federal and state 316(b) regulations cannot be determined until these

rules are finalized.

3 The City of Los Angeles Stormwater Program. (2007) http://www.lastormwater.org/WPD/general/hypern1.htm

4 The City of Los Angeles Bureau of Sanitation (2007). http://www.lacity.org/san/sanmact.htm
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

4-1

4.0 IMPINGEMENT MORTALITY REDUCTION OPTIONS

As stated previously, technologies considered for compliance with EPA’sentrainmentreduction

performance standards would also be applicable for the impingement mortality reduction standards.

Technologies that would only reduce impingement were also evaluated at SGS. These technologies

could be used by LADWP if the entrainment reduction standard were met through other compliance

measures or the claim of meeting the impingement mortality reduction performance standard due to

intake location and utilization of a velocity cap is rejected by permitting agencies. The previous

concerns expressed for closed-cycle cooling or dramatic reductions in cooling water flow to reduce

entrainment are also valid when considering impingement. The following sections address these

technologies with consideration of updated information developed since 2004.

4.1 COARSE-MESH MODIFIED TRAVELING SCREENS

The velocities approaching the existing traveling water screens are 0.6 ft/sec at Units 1 and 2 and 0.7

ft/sec at Units 3. These velocities are within the range of velocities that provide good survival for

most impinged species with traveling screens that have been modified for fish protection (Ristroph

screensinAlden’soriginalreport). LimitedsurvivaldataexistforspeciesimpingedatSGS.

Therefore, Alden still recommends conducting pilot studies before full-scale installation. If a pilotscalestudytodocumentimpingementsurvivalrateswasconductedatLADWP’sHarborGenerating

Station (which has velocities similar to SGS), the results would also apply to survival of impinged

organisms at SGS.

The onshore location of the existing traveling screens presents the same issue as other LADWP

facilities. Impinged organisms collected from the screens will have to be transported a considerable

distance to a safe release point. In addition, fish and shellfish species and their associated life stages

tend to vary considerably in terms of their ability to tolerate the collection and handling associated

with this option, which emphasizes the need for species and life-stage-specific testing to verify

survival rates. Alden believes that methods exist for maintaining a clean fish return system. Two

cleaning methods are summarized in Attachment F

Finally, concern has been expressed with biofouling of the exposed (above water surface) screening

components during continuous operation of the screen. Although this may be a valid concern,

assessment could easily be performed during a pilot study. Development of a fouling control

technology could be a component of the pilot study. However, rather than confound the biological

assessment component of the study, it may be desirable to conduct a small-scale, focused study for

evaluating biofouling conditions. Costs for this component of a pilot study have not been developed.

Conclusion

Coarse-mesh modified traveling screens are still a viable alternative for impingement mortality

reduction. The ability to meet an impingement mortality performance standard would depend on the

species present, and Alden is uncertain if this standard could be met with the species present at SGS.

4.2 WIDE-SLOT CYLINDRICAL WEDGEWIRE SCREENS

LADWP could install wide-slot cylindrical wedgewire screen intakes at SGS to reduce fish

impingement. Six stainless steel T-84 screens with 9.5 mm slot opening would be required to

accommodate the total facility flow. JohnsonScreen’sZ-alloy, a nickel-copper alloy, could be used

to reduce biofouling of the screens. This would require five additional screens and more than double

the cost per screen. These screens would be mounted onto two intake pipes connected to the existing
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

4-2

pipe. The design through screen velocity of the screens would be about 0.5 ft/sec with clean screens.

The screens would be angled so that they are parallel to the predominant currents in the area.

Alden originally designed an air-burst backwash system to clean the screens. After discussions with

the screen manufacturer, using an air-burst system would not be practical for screens located more

than a few hundred feet from the compressor unit. As a result, alternative methods of cleaning the

screens would be necessary. One potential method is to build an offshore platform to house the

necessary air-burst equipment. A second option would use divers to regularly inspect and clean the

screens. Both these options are feasible; however, the air-burst system may be a better alternative, as

it would allow remote cleaning of the screens regardless of the weather. LADWP would no longer be

able to use the existing heat treatment at SGS without modification of the wedgewire system, as the

backflow would result in the clogging of the screens from the inside. Wedgewire screens designed

with slot openings of 9.5 mm and slot velocities of 0.5 ft/sec or less should successfully exclude all

impingeable organisms.

Conclusions

Wide-slot cylindrical wedgewire screens would meet the impingement standard. However, due to the

offshore location cleaning the screens may be difficult. Any cleaning method proposed for SGS

would have to be tested before full-scale application. The cost for the air-burst backwash system has

been removed from the total cost of the screens in the updated cost table (Table 5-1).

4.3 COARSE-MESH BARRIER NET

Alden originally included a barrier net surrounding the existing offshore intake as an option to reduce

impingement at SGS. After reconsideration of the barrier net, Alden determined that debris loading

and waves could make maintaining a barrier net highly labor-intensive and dangerous. Therefore, a

barrier is no longer considered feasible for SGS.

4.4 MODULAR INCLINED SCREENS

Originally, the MIS was proposed as a technology to reduce impingement mortality by virtue of a 2

mm slot size (the only size for which data are available) and is still a viable option. If the proposed

pilot study is conducted for entrainment reduction, the results of species-specific survival would be

used to develop overall efficacy, which would include impingement survival.

All the ancillary issues associated with traveling water screens (e.g., handling, transport, and

discharge) apply to MIS. The one exception would be elimination of the concern with above-water

biofouling as the system is submerged. The current heat treatment practices used with the existing

intake tunnel and screens would be applicable here. If the MIS proved effective and biofouling issues

were documented during the pilot tests, a heat treatment alternative could be considered.

Conclusion

The MIS is still considered a valid technology for impingement mortality reduction. As with the

traveling screen option, Alden is uncertain if the impingement standard could be met with the species

present at SGS.

4.5 FLOW REDUCTION

Prior to the Court’sDecision,EPAwasconsideringissuingguidancerelativetotherelationshipof

impingement and flow. EPA indicated they were considering guidance that would allow facilities to

assume proportionality between flow and impingement. SGS has completed its year of impingement
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

4-3

sampling and these data could be analyzed to determine if diel and/or seasonal impingement patterns

occur during periods when SGS could reduce flow. As with entrainment, flow reduction remains an

alternative, but can only be considered in conjunction with another technology. That is, the

curtailment in generation required to meet an impingement mortality reduction standard of 80-95% is

not practical or cost-effective.

Conclusion

Consideration of flow reduction remains a possible alternative. Typically, flow reductions need to be

discussed with Corporate Power Supply. Assessment of general trends in load demand can predict

periods where placing a unit(s) on standby would result in some flow reduction credit. Shutting off

pumps during high periods of impingement would result in the need to de-rate the unit(s) to maintain

thermal discharge limits. Use of VSDs could be considered to better control flow reductions and

minimize lost generation. Costs for VSDs have been included in this Addendum. Regardless, neither

option would likely meet the impingement mortality reduction standard.

4.6 CLOSED-CYCLE COOLING

Closed-cycle cooling was assessed on a cursory level in the 2004 report. LADWP is participating in

the closed-cycle cooling retrofit cost evaluation study. The results of this evaluation will identify the

economic penalties associated with this option.

Conclusion

Closed-cycle cooling will meet all performance standards. However, Alden does not believe it is

reasonable to consider it for impingement only.

4.7 ADDITIONAL TECHNOLOGIES

There are no additional technologies that would be suitable for reducing impingement at SGS.
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

5-1

5.0 COST UPDATE

The revised costs presented in Table 5-1 are an update of the estimated costs provided in Table 6-3 of

the original report. The update includes an escalation from 2002 dollars to 2006 dollars, as well as

changes in the site-specific factors that impact the installation and O&M of the compliance

alternatives. The three reclaimed water options that were not included in the 2004 evaluation have

been added to this table. The costs for these three options were calculated using the same

methodology as in the 2004 evaluation.
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

Draft 5-2

TABLE 5-1. ALDEN’S APPRAISAL LEVEL COSTS OF EVALUATED ALTERNATIVES

Estimated from Alden Database

Alternative Construction

Costs

(2006 $)

Replacement

Power

During

Shutdown

(MWh)

Total

Capital

Cost

(2006 $)1

O&M

Costs

(2006 $)

Lost

Generation

(MWh) 2

Annualized

Capital

Costs

(2006 $)3

Incremental

Annualized

O&M Costs

(2006 $)1, 2

Total

Incremental

Annualized

Costs

(2006 $)

Expanded intake and install

fine-mesh Ristroph screens $6,429,000 590,000 $35,929,000 $627,000 2,759 $3,293,000 $686,000 $3,979,000

Retrofit intake with 0.5mm

wedgewire screens

$5,242,000 590,000 $34,742,000 $101,000 412 $3,124,000 $43,000 $3,167,000

Install coarse-mesh

Ristroph screens in existing

intake

$4,256,000 290,000 $18,756,000 $504,000 2,102 $1,774,000 $531,000 $2,305,000

Retrofit intake with 9.5mm

wedgewire screens

$1,557,000 590,000 $31,057,000 $22,000 108 $2,599,000 -$51,000 $2,548,000

Install MIS in existing intake $2,218,000 1,180,000 $61,218,000 $37,000 1,120 $5,070,000 $93,000 $5,163,000

Add VSDs to the existing

circulating water pumps $2,610,000 0 $2,610,000 $0 0 $372,000 $0 $372,000

Limit the number of

operating pumps (option 1) $0 0 $0 $0 1,022,482 $0 $51,124,000 $51,124,000

Use reclaimed water for

Unit 3 $16,996,000 0 $16,996,000 $0 0 $2,420,000 $0 $2,420,000

Use reclaimed water for

Units 3 and one other unit $25,022,000 0 $25,022,000 $0 0 $3,563,000 $0 $3,563,000

Use Reclaimed water for

cooling tower make -up

1,184,000 0 $1,184,000 $0 0 $169,000 $0 $169,000

Retrofit plant with closedcycle cooling system4 $115,584,000 910,000 $161,084,000 $1,546,000 39,734 $20,123,000 $3,454,000 $23,577,000

1. Based on a cost for lost generation of $50 per MWh.

2. Includes costs as a result of any power penalties associated with the technology.

3. Alden assumed a discount rate of 7%, and an amortization rate of 10 years for the capital costs and 30 years for the pilot study and downtime costs.

4. Cooling tower costs based on EPRI study (EPRI 2002a).
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

6-1

6.0 DATA GAPS AND UNCERTAINTIES

As with any assessment of alternatives, there are a number of data gaps and/or uncertainties

associated with individual facility location, design, and operation for specific options. These

uncertainties are further exacerbated by the variability of the biological community characteristics

(e.g. diel/seasonal abundance, life stage, species) at the site.

Table 6-1 provides a summary of these uncertainty considerations for each of the alternatives

considered in 2004 and in this document for SGS.

The data gaps that exist with species composition, survival, diel/seasonal presence and variability and

the location and design of the existing intake can only be reduced by extended abundance sampling

(IM&E studies) or alternative/component-specific pilot studies. Each technology will have a different

efficacy for reduction in station effects. The pilot studies proposed for Harbor Generating Station

(fine-mesh traveling screens) and Haynes Generating Station (MIS) will provide data on lengthrelated, species-specific survival. The results of both studies would also provide survival data that

apply to impingement (coarse-mesh screens). Macrofouling on the continuously operating screens can

be determined during the pilot studies, as well as debris handling capabilities.

Returning offshore organisms to the nearshore area could reduce the survival of collected organisms.

The effects of waves and predation on entrained organisms could be assessed during a pilot study.

Pilot studies could also reduce the uncertainties of the effects of mesh size and approach velocities on

organism survival. These issues, however, would probably be best determined after results from the

above studies were available.

The uncertainties associated with annual variability in species abundance and composition as they

relate to the ability to meet performance standards cannot be reduced by pilot studies. It is anticipated

thatsurvivalamong“hearty”and“fragile’specieswill vary and a change in composition towards

“fragile”specieswilljeopardizecompliancepotential.
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

6-2

TABLE 6-1. DATA GAPS AND UNCERTAINTIES FOR ALTERNATIVES

Alternative Data Gaps Uncertainties

Fine-mesh Traveling

Screens

Length and species-specific survival

data from the screen and fish return line;

Biofouling impacts; and

Nearshore return survival.

Effective mesh size; and

Effective approach velocity;

and

Annual variability in species

composition.

Narrow-slot

Wedgewire Screens

Length and species-specific exclusion

data; and

Biofouling impacts.

Effective mesh size;

Effective“sweeping”velocity;

Effective cleaning method;

and

Annual variability in species

composition.

Modular Inclined

Screens

Length and species-specific survival

data from the screen and fish return line;

Only 2.0 mm slot width has been tested;

Biofouling impacts; and

Nearshore return survival.

Effective mesh size;

Effective approach velocity;

and

Annual variability in species

composition.

Coarse-mesh Traveling

Screens

Length and species-specific survival

data from the screen and fish return line.

Biofouling impacts; and

Plant-side return survival.

Annual variability in species

composition.

Wide-slot Wedgewire

Screens

Biofouling impacts. Effective“sweeping”velocity;

Effective cleaning method;

and

Annual variability in species

composition.

Coarse Mesh Barrier

Net

Macro fouling rate; and

Biofouling impacts.

Ability to maintain the net in an

offshore environment.

Use of Reclaimed

Water from Hyperion

Amount of treated water available;

Changes in availability of water in the

future.

Number of units that could

operate on reclaimed water;

Location of Hyperion

discharge pipe; and

Existing infrastructure

between Hyperion and the

SCS intake

Flow Reduction Seasonal species distribution and

relative abundance.

Generation demand; and

Annual variability in species

composition.

Closed-cycle Cooling Site-specific design details. Unit-specific retrofit.
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

7-1

7.0 CONCLUSIONS

This assessment indicates that:

 There have been no modifications to the design or operation of the SGS CWIS that impact

our 2004 assessment of intake technologies.

 The two new technologies currently available (i.e., Hydrolox and Geiger screens) can be

considered in the same category as modified Ristroph screens. Both of these systems

functiononthe“trapandtransfer”conceptandrequirethesametypeoffishanddebris

returns as Ristroph screens. The potential use of either of these technologies does not change

Alden’spreviousassessment.

 The2006impingementandentrainmentdatadonotalterAlden’sselectionofappropriate

technologies for consideration in reducing entrainment at SGS. The overall efficacy of any

entrainment reduction technology is mitigated by the predominance of very early life history

stages.

 The Court’sdecision to remand restoration and the cost-benefittestseverelylimitLADWP’s

options,butdonotaffectAlden’stechnologyandoperationalmeasuresassessments.

 BasedonEPA’sposition,itisanticipatedthatascheduleextensionwillbeprovidedto

accommodate the rulemaking process. That time can be used to pursue pilot studies and

continue to consider additional options.

 Conclusions for entrainment are as follows:

 Closed-cycle cooling is the only option identified that will meet all performance

standards. The ultimate reduction in flow associated with a marine installation was not

determined.

 Fine-meshtravelingscreensaretechnicallyan“exclusiontechnology.”However, unlike

narrow-slot, wedgewire screens that depend on an air-burst cleaning system, coupled

withambientcurrentsto“carry”impingedfishanddebrisawayfrom theCWIS,this

technologyutilizesa“trapandtransfer”concept.Theprocessof collecting organisms to

assess survival imparts some level of mortality, which is difficult to ascertain in the field.

Consequently, the projected efficacy of this technology will be less than that for narrowslot, wedgewire screens.

 As with the fine-mesh traveling screens, the projected efficacy of MIS will be less than

that for narrow-slot, wedgewire screens. However, depending on the ultimate efficacy

for the fine-mesh screens, this alternative may be as effective as the other fine-mesh

screen options.

 The offshore location of a wedgewire screen installation would prevent to use of a

standard air-burst cleaning system. Installing an offshore platform with the needed air

compressors and equipment or manual cleaning are two potential cleaning options that

would have to be evaluated further.

 The existing heat treatment method cannot be used with typical wedgewire screens, as the

screens would be susceptible to clogging. An engineering assessment for

accommodation of heat treatment would be required.

 Consideration of flow reduction remains a possible alternative. Typically, flow

reductions need to be discussed with Corporate Power Supply. Assessment of general

trends in load demand can predict periods where placing a unit(s) on standby would result

in some flow reduction credit. Use of VSDs could be considered to better control flow
Addendum to the 316(B) Evaluation of the Scattergood Generating Station

7-2

reductions. However, this alternative alone would not meet the entrainment reduction

standard.

 If EPA does not designate closed-cycle cooling as BTA, pilot studies would be necessary

todeterminethe“bestperforming”entrainmentreductiontechnology.

 Using reclaimed water from Hyperion could significantly reduce the circulating water

withdrawal from the ocean. If only Unit 3 used reclaimed water, then a 55% reduction

can be achieved. Using all the available reclaimed water from Hyperion would result in a

flow reduction of over 70 percent.

 Conclusions for impingement only are as follows:

 If the results of the IM&E study are accepted, the impingement mortality reduction

performance standard will be met and no additional technologies are required. If the

results are rejected, the following conclusions are valid.

 Coarse-mesh traveling screens, wide-slot wedgewire, and MIS are still a viable

alternative for impingement mortality reduction.

 A barrier net is no longer considered feasible at SGS due to the location of the intake.

 Consideration of flow reduction remains a possible impingement mortality reduction

alternative. The same comments previously discussed for entrainment reduction apply to

this alternative.

 Although impingement-only alternatives are available, Alden does not recommend

further consideration of impingement-only options in light of the Court’sDecision.

 Based on EPA’sposition, it is anticipated that a schedule extension will be provided to

accommodate the rulemaking process. That time can be used to pursue pilot studies and

continue to consider additional options.
Attachment A Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

1

ATTACHMENT A -

SUMMARY OF 2004 EVALUATION OF SGS

The following provides a summary of the “EvaluationoftheScattergood Generating Stations with

respecttotheEnvironmentalProtectionAgency’s316(b)RulesforExistingFacilities”,December

2004, prepared by Alden Research Laboratory, Inc. (Alden) and EPRI.

Scope of the Analysis

In response to the Rule, Electric Power Research Institute (EPRI) and Alden conducted a strategic

assessment for Los Angeles Department of Water and Power (LADWP) Scattergood Generating

Station (SGS). This assessment evaluated the impact of the Rule on SGS, including potential costeffective compliance alternatives, additional information collection needs, and relative budget

impacts as a result of studies and compliance alternatives.

The major component of this analysis was a preliminary evaluation of alternative fish protection

technologies to meet the applicable performance standards for SGS and discussion of approximate

costs for the feasible alternatives. As part of this alternatives analysis, Alden reviewed operational

options for meeting the applicable performance standards.

This report addressed technologies, operational changes, and restoration measures that LADWP could

implement to meet the Rule. TheU.S.EnvironmentalProtectionAgency’s(EPA’s) favored approach

was to reduce total fish losses, which did not address AEI at the population and ecosystem levels.

Therefore, traditional measures of population and ecosystem health, such as species diversity and

richness, were not addressed. Further, EPA did not consider factors that influence populations such

as compensatory mechanisms, species fecundity, and natural mortality. Therefore, these factors were

not considered.

Technologies and Operational Measures

The preliminary evaluation of alternative technologies and operational measures that could be

considered by LADWP to meet the Impingement Mortality and Entrainment (IM&E) standards at

SGS was presented in the report.

Alden’spreliminaryjudgmentonhowlikelythesealternativeswere to actually meet these standards

was summarized as follows:

Alternative

Will It Meet the Impingement

Mortality Reduction

Standard?

Will It Meet the

Entrainment Reduction

Standard?

Expanded intake with fine-mesh

Ristroph screens

Although impingement mortality is

highly variable, data show that

Ristroph screens incorporating the

latest bucket designs typically

achieve higher survival rates than

older Ristroph screens. LADWP

should consider pilot-scale studies

prior to full-scale installation to

assurethescreens’performance.

Yes

Retrofit intake with 0.5 mm

wedgewire screens

Yes Yes
Attachment A Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

2

Alternative

Will It Meet the Impingement

Mortality Reduction

Standard?

Will It Meet the

Entrainment Reduction

Standard?

Install coarse-mesh Ristroph

screens in existing intake

Perhaps, although impingement

mortality is highly variable. Data

show that Ristroph screens

incorporating the latest bucket

designs typically achieve higher

survival rates than older Ristroph

screens. LADWP should consider

pilot-scale studies prior to full-scale

installationtoassurethescreens’

performance.

No

Retrofit intake with 9.5 mm

wedgewire screens Yes No

Coarse-mesh barrier net Yes –provided that the barrier can

be maintained in place No

Install Modular Inclined Screen

(MIS) in existing intake Yes No

Limit the number of operating

pumps

No; a reduction in the number of

fish impinged might expected

Yes, if the added flow

reduction results in an overall

flow reduction of 60% or

greater. Alternatively,

reductions targeted during

periods of peak

ichthyoplankton abundance

could meet the standard

without a 60% flow reduction.

Retrofit plant with closed-cycle

cooling system Yes Yes

The annualized costs of these alternatives as compared with the costs EPA used in developing the

Rule were:

Alternative Alden’sAnnualizedCosts

(2002 $)

EPA’sAnnualizedCosts

(2002 $)

Expanded intake with fine-mesh

Ristroph screens $4,777,000

Retrofit intake with 0.5mm

wedgewire screens $4,191,000

Install coarse-mesh Ristroph

screens in existing intake $2,657,000

Retrofit intake with 9.5mm

wedgewire screens $3,543,000

Coarse-mesh barrier net $90,000

Install MIS in existing intake $7,073,000

Limit the number of operating

pumps

$53,723,000

Retrofit plant with closed-cycle

cooling system $42,663,000

$0
Attachment A Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

3

Key findings of our preliminary (2004) analysis are:

 The existing offshore intake with a velocity cap may provide credit toward meeting the

IM&E standards. The magnitude of the credit cannot be determined until LADWP samples

near shore fish populations and compares the densities of fish with those it observes in the

IM&E Study.

 Eight technological or operational options are considered to have potential for meeting the

impingement mortality and/or entrainment reduction standards and deemed practicable from

an engineering standpoint. These options are: expanded intakes with fine-mesh Ristroph

screens, narrow and wide-slot wedgewire screens, coarse-mesh Ristroph in existing intakes, a

coarse-mesh barrier net, an MIS unit, limited pump operation, and closed-cycle cooling. The

technologies that solely reduce impingement were evaluated in case LADWP were to meet

the impingement mortality standard with a technology while meeting the entrainment

standard through operational changes or initiating restoration measures.

 Of the four options that could meet the entrainment reduction standard, Alden estimates the

annualized costs range from $4,777,000 for expanding the intake and installing fine-mesh

Ristroph screens to $53,723,000 for reducing flow during periods of high entrainment.

 Both a barrier net and wide-slot wedgewire screens have the greatest potential to meet the IM

standard. The annualized costs for these technologies are $90,000 for a coarse-mesh barrier

net and $3,543,000 for wide-slot wedgewire screens.

 EPA did not assign a technology upgrade cost to SGS, which implies that it considers the

facility to be operating with BTA. The Rule provides considerable latitude to the Director to

determine what constitutes “significantly greater than.” Presumably, California

Environmental Protection Agency will have discretion in how the Cost-Cost would be

applied in cases where EPA assigned no monetary value to upgrades that the Director feels

are necessary to meet the performance standards. Because of these uncertainties, it is not

possible to determine if LADWP could satisfy the requirements of the Cost-Cost test at SGS.

The following general considerations were used to develop conceptual designs of alternative fish

protection technologies for application at SGS. Alden used the criteria to evaluate the relative

advantages and disadvantages of each option and to select for consideration those technologies with

the greatest potential to meet the performance standards at SGS. The criteria were:

 Alternatives should be designed to reduce impingement mortality of impingeable5fish by 80–

95%fromthe“calculationbaseline.”

 Alternatives should be designed to reduce entrainment by 60–90% from the“calculation

baseline.”

 Alternatives should provide protection for species present in the ocean that are potentially

susceptible to IM&E.

 The period of protection is year-round for impingement and entrainment

 Alternatives should take into consideration current project design features, as summarized in

Table 2-3 in the Addendum (revised Table 3-1 from 2004 report).

5 EPA defines an entrainable organism as one that will fit through a 3/8 in. mesh. By extension, any organism

thatistoolargetobeentrainedthrougha3/8in.meshwouldbeconsidered“impingeable.”
Attachment A Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

4

 Alternative designs should have suitable conditions for fish protection over the full range of

intake flows and water depths at the CWIS.

 Alternatives should provide effective protection throughout the entire water column such that

they are effective with all species potentially susceptible to IM&E.

 Alternatives should function under expected debris loading and hydraulic conditions in the

estuary (i.e., reasonable cleaning techniques are available and demonstrated).

 Alternatives should preserve, to the extent possible, the existing civil/structural features.

 Alternatives should meet worker and public safety requirements.

 Alternatives should not adversely impact navigation.

 Alternatives should be compatible with the other aesthetic and recreational features of the

region.

The screening process was as objective as possible. However, in assessing the potential for

application of fish protection schemes under physical, hydraulic, and in environmental conditions that

they have never been applied, the Team had to use best professional judgment based upon experience.

The Team deemed a technology to have proven biological effectiveness if test data (preferably from

full-scaleapplication)wereavailablethatdocumentedatechnology’seffectivenesswithoneormore

of the species present at that site. If engineering data exist in sufficient detail to develop a conceptual

design, and/or if the technology has been constructed at another site, we judged it to be an available

technology. Each technology was qualitatively assessed to identify whether it had biological and/or

engineering advantages over the other alternatives. For example, an intake technology that has been

proven effective at reducing losses for many species and under a variety of intake conditions has a

biological advantage over one that has been proven effective with a few species or under limited

intake conditions. From an engineering perspective, one technology may hold an advantage over

another if the civil/structural requirements for installation are substantially less.

A few emerging technologies show potential to meet the IM and potentially entrainment reduction

standards but have not been fully developed and/or tested for biological effectiveness. These

technologiesincludeBeaudrey’sFishProtectionSolution(FPSTM), Filtrex filter system, fine-mesh

flat-panel screens with Debris and Organism Collection (DOC) system,andGeiger’sMultiDiscTM

Screening System.

 Beaudrey’sFPSTM system consists of a fine-mesh fixed screen with a fish collection scope

positioned below the water’ssurface. The collection scope travels along the screen face,

collecting fish and debris, with suction provided by a fish pump.

 Filtrexfiltersystemconsistsoffilter“candles”approximately5incheslongmadeofplastic

wafers stacked and fastened together with a central spring. Groves between stacked wafers

provide filtration from 5 to 40 microns, and the flow capacity of each candle is approximately

10 gpm at a headloss of 4 feet. Filter candles are assembled together on 3 ft by 3 ft modules

with filter arrays on three sides and cleaned using a backwash system. During backwashing,

the stacked wafers are allowed to separate by compression of the central spring, and the

backwash flow removes debris. Debris and fish then float downstream of the filter modules

to a bypass pump and return system.

 DOC system consists of flat panel 0.5 mm screens, a debris and organism collection nozzle, a

fish pump, and fish return troughs and piping. The collection nozzle would be located close

to the flat panel screen face just below the water’ssurface and would remove debris and
Attachment A Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

5

impinged fish from the screens. Submerged fish pumps would create suction for each nozzle.

The fish pumps would discharge fish and debris through piping and/or troughs back to the

source waterbody. High-pressure spray wash headers and debris troughs would be located at

deck level for additional debris removal for each screen.

 TheGeigerMultiDiscTM ScreeningSystemconsistsofasingle-pass, front-wash, vertical

screenwithfishhandlingcapabilities.Thisdesignresultsina“zerocarryover”fish/debris

condition. Mesh size and material (e.g., woven mesh or perforated plate) and screen rotation

speed can be designed for site-specific needs.

The technologies described above could prove effective in meeting the IM&E reduction standard.

However, the Team has not included them for further evaluation because they have not been fully

developed or have not been biologically proven.

Based on the literature summarized in Appendix B (provided with the 2000 evaluation), we consider

the following concepts to have limited or no proven biological effectiveness (i.e., they have not

substantially reduced entrainment or impingement in past applications as indicated in Table 2-3 in the

Addendum.):

 Infrasound

 Mercury lights

 Chemicals

 Electric screens

 Water jet curtains

 Hanging chains

 Visual keys

 Inclined plane screens

 Submerged traveling water screens

Behavioral barriers to protect juvenile and adult fish have been the subject of extensive research. The

use of strobe lights to elicit a behavioral response is supported by the results of laboratory and cage

test studies that have demonstrated strong avoidance by several fish species to strobe lights. Strobe

lights have been evaluated for repelling or guiding juvenile and adult fish away from water intakes

(EPRI 1994, 1999) and, in many cases, toward bypasses for transport to a safe release location. There

is some evidence that combining strobe lights with an air bubble curtain can provide effective fish

deterrence. However, results have been species- and site-specific.

The focus of recent studies involving underwater sound technologies has been on the use of low- and

high-frequency acoustic systems that were not available for commercial use until the 1990s. Highfrequency (120 kHz) sound has been shown to effectively and repeatedly repel members of the genus

Alosa (American shad, alewife and blueback herring) at sites throughout the U.S. (Ploskey et al.

1995; Dunning 1995; Consolidated Edison 1994). Other studies have not shown sound to be

consistently effective in repelling species such as largemouth bass, smallmouth bass, yellow perch,

walleye, rainbow trout (EPRI 1998), gizzard shad, Atlantic herring, and bay anchovy (Consolidated

Edison 1994).
Attachment A Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

6

Based on the results of behavioral barrier studies conducted over the past 30 years, a hybrid barrier

consisting of light, sound, and air bubbles would be most effective on Alosids. Given that Alosids are

not impinged at SGS, a hybrid barrier would likely not reduce impingement to a level that meets the

impingement mortality reduction standard, and thus the team had eliminated these types of barriers

from further consideration at SGS.

The existing intakes at SGS could be retrofitted with Ristroph screens. Ristroph screens are very

similar to conventional traveling water screens except that they are designed with extra features to

collect and transport impinged organisms safely back to the waterbody. Fine-mesh Ristroph screens

with an approach velocity of 0.5 ft/sec have the potential to meet both standards, while coarse-mesh

Ristroph screens may meet only the impingement mortality standard. Continuous rotation along with

spray wash systems provides the Ristroph screens with an automatic screen-cleaning feature. This

gives them an engineering advantage over fixed screens, barrier nets, and bar rack barriers, all of

which would require an additional cleaning system. The Team has considered fine-mesh Ristroph

screens to be a viable alternative for reducing both IM&E at SGS. Fine-mesh Ristroph screens with

an expanded intake, to reduce the screen approach velocity to 0.5 ft/sec, can be considered a viable

alternative for reducing both IM&E at SGS. Coarse-mesh screens have also been evaluated, since

SGS may be able to meet the entrainment reduction standard through other compliance measures.

Modification of the screen and pump structure to incorporate physical barriers or diversion systems,

such as angled screens to prevent impingement, would be difficult. Traveling water screens have an

engineering advantage over other physical barriers (angled fixed screen, rotary drum screen, barrier

net, bar rack barrier, infiltration intakes, and porous dikes) (Table 2-3 in Addendum). Installation of

rotary drum screens and porous dikes would require a much larger area than conventional traveling

screens because of the lower design velocity. Rotary drum screens are typically installed in channels

where water elevations are relatively constant and water depths are less than 12 ft, which is not the

case at SGS. Bar rack barriers are typically designed to have spacing greater than 1 in. and would not

effectively prevent the entrainment of early life stages. However, they may effectively reduce

impingement. The Team has not included any of these options in this evaluation because they do not

have significant advantages over other impingement mortality reducing technologies included in this

report.

The Modular Inclined Screen (MIS) and Eicher screen have a biological and engineering advantage

over louvers, angled bar racks, and angled screens in preventing impingement. Both screens offer the

potential to effectively divert most species by using smaller structures than the other screen concepts.

The MIS, for example, is designed to operate at velocities up to 10 ft/sec. The Eicher screen is

designed for installation in hydroelectric project penstocks and, therefore, has not been included in

this evaluation. The MIS could replace a section of the inlet chamber upstream of the trash racks;

therefore, the Team has evaluated this technology as an option to reduce impingement at SGS.

Cylindrical wedgewire screens have an engineering advantage over the porous dike, infiltration

intake, and bar rack barriers (Table 2-3 in Addendum). Wedgewire screens are designed for a

through-screen velocity of 0.5 ft/sec, therefore automatically meeting the impingement mortality

standard (Compliance Option 1). Wedgewire screens have cleaning features that make them easier to

clean than other fixed screens and barrier nets. This cleaning feature requires the presence of a

sweeping current to be effective. Tidal action could potentially provide this sweeping current.

Cylindrical wedgewire screens have a biological advantage in that they can exclude more life stages

from intake water than conventional screens and bar racks. For this reason, the Team has included

both narrow and wide-slot, wedgewire screens in the preliminary evaluation for SGS.
Attachment A Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

7

Aquatic filter barriers (AFB) could be used to prevent the entrainment of early life stages of fish. The

AFB has an engineering advantage over barrier nets relative to cleaning (Table 2-3 in Addendum).

An AFB has two layers of material, with an air purge system installed between the layers to permit

automatic cleaning of accumulated silt and debris. This cleaning system can also free impinged fish

larvae and other non-motile life stages. This technology requires low through material velocities and,

therefore, an extremely large surface area and may effect navigation in the vicinity of the intake. As

an AFB would require a large surface area, the Team does not believe that the barrier could be held in

place in an open ocean environment and has, therefore, eliminated the AFB from further

consideration.

Fine-mesh barrier nets (<0.5 mm) are easily fouled by silt and algae, require labor-intensive cleaning,

and are considered experimental for reducing entrainment at this time. However, coarse-mesh nets

could reduce impingement if they were installed in a low velocity zone and periodically cleaned to

remove debris accumulation and biofouling growth. Barrier nets require less surface area than AFBs,

although they may also hinder navigation and recreation at SGS. The Team has included a coarsemesh barrier net in the preliminary evaluation as a potential low cost option to reduce impingement at

the SGS CWIS.

The preliminary screening of intake technologies available for fish protection (Table 2-3 in

Addendum) indicates that two intake alternatives have the greatest potential for application to reduce

fish IM&E at SGS:

 Installation of fine-mesh [i.e., 0.5 mm (0.02 in.) square woven mesh] Ristroph screens with

an expanded screenhouse; and

 Wedgewire screens with 0.5 mm openings.

Four additional intake alternatives that would act to reduce fish impingement only are:

 Installation of coarse-mesh Ristroph screens in the existing screenhouse;

 Wedgewire screens with 9.5 mm openings;

 Coarse-mesh barrier net; and

 Installation of a MIS in the intake.

Two flow reduction options to reduce fish impingement and entrainment at SGS’intakestructure

have been identified. These options are:

 Reduced circulating water pump operation; and

 Installing closed-loop cooling system.

Current plant operating procedures dictate operation of all pumps per unit to maintain the plant

discharge within the permitted thermal limits. Additional flow limitations could be implemented

during periods of peak abundance of entrainable organisms. To maintain the plant discharge within

the permitted thermal limits, reduced pump flow may require a reduction in plant output.

Flow limitation could be achieved by shutting down pumps, throttling discharge pumps, or installing

variable speed drives on some of the pumps. A more detailed analysis would be necessary to

determine if throttling valves would be a more cost effective solution than variable speed drives on

the circulating water pumps.
Attachment A Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

8

Closed-cycle cooling could greatly reduce both IM&E at SGS. Mechanical or natural draft wet

towers would require less modification to the existing circulating water system piping and less real

estate than dry cooling towers. The costs for construction of a wet mechanical cooling tower are

about 60% less than the natural wet cooling tower. Natural wet cooling towers require less energy to

operate and have lower annual costs then a wet mechanical draft tower. However, wet mechanical

draft towers generally have less aesthetic and air quality impacts than natural draft wet towers. SGS

is surrounded by residential, recreational, and park areas, as aesthetics and air quality issues would

probably be greater for natural draft towers than for mechanical draft towers. For these reasons, wet

mechanical draft towers were chosen as the closed-cycle cooling system option for preliminary

evaluation.
Attachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

1

ATTACHMENT B -

LADWP RESTORATION OPTIONS

1.0 INTRODUCTION

In 2004, Alden Research Laboratory, Inc. (Alden) and the Electric Power Research Institute (EPRI)

conducteda316(b)strategicassessmentfortheLosAngelesDepartmentofWaterandPower’s

(LADWP) Generating Stations: Harbor Generating Station (HGS), Haynes Generating Station

(HnGS), and Scattergood Generating Station (SGS). As part of that assessment, the use of restoration

as a 316(b) compliance alternative was evaluated. That evaluation analyzed restoration project

categories, and included summaries of nationwide restoration projects.

The purpose of this attachment is to update the Alden and EPRI evaluation, provide information on

specific projects applicable to offsetting entrainment and/or impingement losses at the LADWP

Generating Stations, summarize the process of implementing restoration projects, and identify data

gaps that are required to be addressed prior to developing a 316(b) Restoration Plan for inclusion in

the Comprehensive Demonstration Study for each Generating Station.

2.0 SUMMARY OF 2004 ALDEN/EPRI RESTORATION EVALUATION

2.1 TYPES OF RESTORATION APPLICABLE TO 316(B)

The 2004 Alden/EPRI evaluation identified several categories of restoration projects that have been

used at other facilities nation-wide. These included:

 Wetlands restoration;

 Fish stocking;

 Submerged aquatic vegetation (giant kelp) restoration;

 Provision of fish passage;

 Contribution to a restoration fund; and

 Water quality improvements.

The two general requirements for the use of restoration are (1) a demonstration that the use of

technologies and/or operational measures was evaluated, and the use of restoration measures is

appropriate because meeting the performance standards through implementation of technologies

and/or operational measures is less feasible, less cost-effective, or less environmentally desirable than

meeting the performance standards in whole or in part through the use of restoration, and (2) a

demonstration that the use of restoration will produce ecological benefits (production of fish and

shellfish) at a level that is substantially similar to that which would be achieved through

implementation of technologies, operational measures, and/or alternative site-specific requirements.

2.2 SPECIFIC RESTORATION EXAMPLES FOR HGS, HNGS, AND SGS

Alden/EPRIprovidedseveralexamplesofpotentialrestorationprojectsapplicabletoLADWP’s

coastal generating stations. These examples are summarized below.
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Fish Stocking

Stocking of fish would provide direct replacement of affected species. Examples included stocking of

lake sturgeon (Coosa River, Georgia/Alabama), Atlantic Sturgeon (Patuxent River, Maryland),

American shad (Susquehanna River, Maryland/Pennsylvania), and white seabass (southern

California).

Habitat Protection Programs

Habitat restoration, and particularly wetland restoration, has become increasingly popular due to the

decline of various habitats with time. Participation in a restoration program would also provide the

benefit of fish production. Examples included the San Dieguito Lagoon restoration (SCE San

Onfore), the Morro Bay Habitat Enhancement Program (Duke Energy Morro Bay), the Delaware Bay

Estuary Enhancement Program (PSEG), and the Santa Monica Bay Restoration Commission (Los

Angeles, California). Other examples were provided related to restoration-related groups that might

assist in the facilitation of restoration projects, including the National Centers for Coastal Ocean

Science, the National Estuaries Restoration Inventory, the NOAA Community-based Restoration

Program,theU.S.FishandWildlifeServicePartnershipforFishandWildlife,andCoastalAmerica’s

Corporate Wetlands Restoration Partnership.

Dam Removal or Fishway Construction

The U.S. Fish and Wildlife National Fish Passage Program is designed to restore native fish and other

aquatic species to self-sustaining levels by reconnecting habitat that has been fragmented by barriers,

where such reconnection would not result in a net negative ecological effect. Examples included

installation of fishways (Delaware Bay), and a potential dam removal project (Rindge Dam, Malibu

Creek).

Alternative Restoration Projects

Other potential restoration projects could include runoff abatement programs and removal of

contaminated sediments to improve water/sediment quality and habitat.

2.3 316(B) RESTORATION IMPLEMENTATION PROCESS

The use of restoration as a compliance alternative will require coordination and agreements among a

number of regulatory agencies and stakeholder groups. If LADWP decides to implement a project

that it would fund and manage in cooperation with federal, state, and local resource agencies, the

process could include the following at a minimum:

 Identify projects with involvement of resource agencies and stakeholder groups.

 Scale project to meet desired goals for offsetting losses attributable to impingement mortality

and entrainment (IM&E).

 Develop implementation plan for restoration with input from resource agencies and

stakeholder groups including:

 Setting goals for project,

 Defining milestones that can be used to measure performance,

 Conducting initial biological and engineering data for plan,

 Developing a verification monitoring plan to ensure that milestones are being met and the

goals for offsetting IM&E losses are achieved, and
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 Ensuring that the plan incorporates adaptive management so that restoration activities and

monitoring can be modified to ensure that the final goals of the project are achieved.

 Prepare information for permitting

 May require preparation of Environmental Impact Report and responding to comments

from reviewers that will result in modifications to the project and changes to the

implementation and monitoring plans.

 Use implementation plan to develop requests for proposals for engineering and construction.

 Review proposals and select contractors for management, construction, and monitoring.

 Implement verification monitoring and schedule periodic updates on progress and continue

reviews involving resource agencies and stakeholders.

Due to the complexity, cost, and time involved in this process, another option is to fund an existing

project. LADWP could contribute money to the project and ensure that the existing verification

monitoring plan will supply the necessary information to ensure that the goals of the restoration are

being achieved. Additional funding may be necessary to ensure that verification monitoring is

adequate. An example of the successful implementation of this approach is the funding provided from

the Moss Landing Power Plant (MLPP) to the Elkhorn Slough Foundation (ESF) for their programs

related to the preservation and enhancement of the Elkhorn Slough National Estuarine Research

Reserve (see attached). The success of this program has been widely recognized, and is largely due to

the maturity of the management plan for the slough that was developed by the ESF. The ESF has been

able to leverage the money provided by MLPP many times over to accomplish much more than could

ever be achieved from a single restoration project. The successful implementation of this approach

requires identifying an existing entity like the ESF that has a proven track record with implementing

restoration programs.

3.0 SPECIFIC RESTORATION PROJECTS APPLICABLE TO SCATTERGOOD

GENERATING STATION

The purpose of this section is to identify specific, local restoration projects that are potentially

applicable to the SGS, and identify data necessary if each project were to be selected for

implementation. Potential restoration projects should be considered based on their ability to offset

entrainment and/or impingement at SGS.

Any specific conservation, enhancement, or restoration project that is to be used for this purpose

should have a nexus (i.e., offset) to the impingement and entrainment (IM&E) effects of the power

plants. The projects that were evaluated to offset potential IM&E losses fell into three basic

categories:

 Projects that would directly restore or enhance habitat in the vicinity of SGS (Los Angeles

and Orange counties);

 Projects that enhance habitat through watershed management; and

 Projects that enhance the nearshore coastal environment in the vicinity of SGS (Santa Monica

Bay and San Pedro Bay).

Projects that result in removal of accumulated sediment from coastal wetlands would increase the

coastal salt marsh habitat, which would, in turn, increase their biological productivity. Projects that

restore the tidal flow between the ocean and the wetlands to historic levels would have a similar effect

on productivity. Other projects that involve watershed management could reduce wetland
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sedimentation and thus preserve existing wetland habitat. Projects that enhance the biological

productivity of Santa Monica and San Pedro bays could directly offset the loss of productivity in the

same waterbody that occurs as a result of IM&E losses at the three power plants.

The“value”oftheecologicalservicesorbenefitsthatwillresultfromimplementationofanyofthese

restoration projects will be assessed using various habitat models to demonstrate that the ecological

“credits”gainedthroughrestorationwilloutweightheecological“debits”causedbytheIM&E

losses.

Using local environmental planning documents and resource agency recovery plans as references,

three major categories of projects have been identified that are appropriate for inclusion as restoration

alternatives to offset IM&E losses. These projects have the potential to create, restore, and preserve

habitat equivalent to the amount of habitat that produced the estimated numbers of impinged and

entrained species of fishes and target invertebrates, as well as the other ecological and environmental

effects of IM&E. Restoration projects are presented that offset potential population effects of IM&E

on specific species and at the same time contribute to the overall health of nearshore/coastal habitats.

3.1 COASTAL WETLAND PROJECTS

At one time, coastal lagoons, salt marshes, and other wetlands created by the merging of creeks and

rivers with the Pacific Ocean characterized the shoreline of Santa Monica Bay, Los Angeles and Long

Beach Harbors, and shoreline areas further south. As these coastal areas became more densely

populated and more highly developed, most of the marshes were filled and the creeks and rivers were

channeled into concrete waterways to eliminate the periodic flooding that plagued these low-lying

areas. In recent years, public sentiment has turned to the task of preserving the remaining wetlands in

this area and, where possible, to restoring those wetlands to a state that more closely resembles

historic conditions.

This category of projects includes actions taken directly within the boundaries of these wetlands to

restore and/or enhance habitats that serve as spawning grounds for fish and other aquatic species.

Projects in this category include the restoration of historic sediment elevations, the redirecting of

freshwater streams into the channels that historically fed these areas, and the reopening of channels to

the ocean that allow tidal flow into and out of the wetlands.

The anticipated results of restoring and protecting the wetland habitats will be used to forecast the

project’squalitativeandquantitativebenefitsrelativetobaselineIM&Elosses.Projectsconsidered

for evaluation include several within Santa Monica Bay, as well as projects in nearby Orange County.

Project summaries are presented in order of coastwise location (upcoast to downcoast).

3.1.1 Zuma Wetlands

Zuma Wetlands is a small, 6-acre, freshwater marsh and creek situated about 20 miles upcoast of the

SGS. The wetlands have historically served as a wildlife corridor and nesting site for a variety of

birds and small mammals. By the early 1990s, periodic dumping of surplus construction and road

building material had heavily impacted the wetlands and surrounding uplands. The existing wetlands

were greatly reduced and, in many areas, native species were completely replaced by exotic

ornamental trees, annual grasses, fennel, mustards, and thistles. High visitation at Zuma Beach has

also impacted the site.

Wetland restoration efforts commenced in 1998 and include the excavation of construction fill,

recontouring of upland habitats, removal of exotic plant species, planting of more than 5,000 native
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plants, and the re-creation of an additional 21⁄2 acres of freshwater wetland/dune/riparian habitat.

Restoration of this wetland is an ongoing process, which continues at this time.

3.1.2 Malibu Lagoon

Located approximately 15 miles upcoast of the SGS, Malibu Lagoon is a coastal lagoon and salt

marsh fed by Malibu Creek and its associated watershed. During much of the rainy season (winter

and spring) the lagoon opens into the northern end of Santa Monica Bay. During the summer and fall,

reduced flow from the creek and seasonal rebuilding of the beach area dams the lagoon and cuts off

its connection with the ocean, except during periods of extreme high tide and/or large ocean swells.

Lacking a connection to the ocean, the lagoon becomes a brackish water body whose salinity

fluctuates with freshwater input and evaporation. Several habitat restoration or enhancement projects

are in existence that affect the Malibu Creek and Lagoon directly, or indirectly, due to their influence

on creeks that are tributaries of Malibu Creek.

3.1.3 Topanga Lagoon and Creek

Historically, the Topanga Lagoon covered more than 30 acres, but has now been reduced to only 2

acres (mostly due to the deposition of 800,000 cubic feet of fill into the lagoon during the 1934

realignment of the Pacific Coast Highway). Located approximately 10 miles upcoast of the SGS, the

lagoon is fed by Topanga Creek and its associated watershed. Over the years, development in the area

has increased sedimentation rates, which constrain the channel and impede fish migration by species

that include the endangered Steelhead trout. Upper Topanga Creek is listed on the State 303(d) list of

impaired waterbodies. The Santa Monica Bay Restoration Commission, in conjunction with other

agencies, has conducted a comprehensive Topanga Creek Watershed and Lagoon Restoration

Feasibility Study to identify ways to restore these resources. The California Department of Parks and

Recreation recently purchased 1,659 acres of lower Topanga Canyon, including the current and

historic lagoon sites.

3.1.4 Ballona Wetlands

Located about 4 miles upcoast of the SGS, the Ballona Wetlands contains saltwater marsh, freshwater

marsh, coastal bluff, and dune habitats. The area, at one time, covered approximately 2,000 acres, but

due to human encroachment and development, the wetland has been greatly reduced over the last 100

years. In recent years, about 340 acres of the wetland has been preserved due to the efforts of

numerous organizations that are dedicated to the preservation and restoration of the wetland. These

organizations include Friends of Ballona Wetlands, the Ballona Wetlands Foundation, and Heal The

Bay. Portions of the wetland include tidally influenced marsh areas that act as a nursery for Santa

Monica Bay marine species. Restoration plans for this portion of the wetland are still being

developed. Ballona is the only remaining large coastal wetland in Los Angeles County.

3.1.5 Los Cerritos Wetlands

The Los Cerritos Wetlands is located about 30 miles downcoast of the SGS and immediately adjacent

toLADWP’sHnGS.The wetland straddles the Los Angeles-Orange County border. It currently

consists of about 130 wetland acres, with nearly 800 acres of degraded habitat proposed for

restoration. Historically, it consisted of about 2,400 acres and included what is now Alamitos Bay.

Since much of the site was modified due to former oil development activities, most of the land was

privately held. In 2006, the California Coastal Conservancy was one of several agencies that

purchased 66 acres of the wetlands, and hopes to acquire more. The Los Cerritos Wetlands Land

Trust of Long Beach and Seal Beach is one organization committed to restoration of the wetlands. A

conceptual restoration plan includes full tidal restoration (inland to Westminster Avenue) via

connection to the lower San Gabriel River. While the proximity of the Los Cerritos Wetlands to the

HnGS makes it an attractive restoration option, other considerations associated with the project make
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it less than ideal. The recently submitted final report of the City of Long Beach, Los Cerritos

Wetlands Study Group (available as a downloadable pdf file at

http://www.longbeach.gov/plan/pb/cpd/los_cerritos.asp) cited several pressing issues that need to be

dealt with in order to proceed with any of the proposed restoration projects. Two of these issues are

the numerous and varied zoning and jurisdictional concerns related to the area of the former wetlands,

andthearea’shistoryofuseasahazardouswastedisposal site. These concerns are reflected in the

ranking of this restoration option.

3.1.6 Bolsa Chica Lowlands

The Bolsa Chica Lowlands Restoration Project is located about 35 miles downcoast from the SGS

adjacent to the City of Huntington Beach. The purpose of the project is to restore portions of the

wetland ecosystem of the Bolsa Chica lowlands. The project area covers about 1,247 acres, and has

restored tidal influence from the Pacific Ocean to about one-half of this area to reinvigorate the

wetland ecosystem. To achieve the biological benefits of tidal restoration, a direct connection to the

Pacific Ocean was reestablished through the creation of a new tidal inlet that cut through Bolsa Chica

State Beach and crossed the Pacific Coast Highway near the Huntington Mesa. Construction is

currently underway and is anticipated to span a total of 2.5 to 3 years, in order to avoid or minimize

impacts to fish and wildlife resources, coastal traffic, and beach recreation.

3.1.7 Huntington Beach Wetlands

The Huntington Beach Wetlands are located about 42 miles downcoast from the SGS, adjacent to the

Huntington Beach Generating Station. The total area of the wetlands is about 180 acres. Over the

years, the wetlands have been divided into a number of smaller parcels by the development of the

Huntington Beach area. The Huntington Beach Wetlands Conservancy plans to acquire the entire 180

acres and restore it in accordance with a comprehensive wetlands restoration plan that they are

currently preparing. Restoration will include the improvement or re-establishment of tidal circulation

within the wetlands. This will provide additional habitat for local fish and invertebrate species. In fall

2006, AES Huntington Beach was required to restore 66.8 acres of the Huntington Beach Wetlands to

offset entrainment losses for Units 3&4.

3.1.8 Upper Newport Bay Ecological Reserve

Newport Bay is located approximately 50 miles downcoast from the SGS. The Upper Newport Bay

Ecological Reserve was created in 1975 as result of the purchase of 527 acres of land in and around

the bay from the Irvine Company and the transfer of 214 acres of tidal wetlands from the County of

Orange to the state. An additional 11 acres of land in Big Canyon was added in 1982, bringing the

total acreage of the Ecological Reserve to 752 acres. It is managed by the California Department of

Fish and Game. There are currently a number of restoration projects within Upper Newport Bay. The

largest is the dredging of 2.1 million cubic yards of sediment. The project will restore and maintain

tidal movement within much of the Bay. Much of the dredging project still needs funding, as well as

post-project monitoring and maintenance. Dredging will provide additional habitat for fish species

already present in Upper Newport Bay.

3.2 COASTAL WATERSHED PROJECTS

Projects that control or reduce sediment transport into coastal wetlands may include erosion control

projects along upland watercourses; construction of catchment basins, swales, and other sediment

containment features; land acquisition for purposes of creating conservation easements; minimizing

runoff from development activities; restoration of floodplain habitat; and other Best Management

Practices. The implementation of watershed management projects as part of the restoration plan is
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based on the nexus between the loss of wetland area and its associated reduction of biologically

productive habitat with the infilling of the wetlands by sediments eroded from its watershed.

3.2.1 Las Virgenes Creek Restoration Project

Las Virgenes Creek is an important tributary of Malibu Creek and Lagoon. Las Virgenes joins Malibu

Creek approximately 5.5 miles from the coast (Malibu Lagoon). The City of Calabasas plans to

remove over 250 linear feet of a concrete-lined portion of the creek to help restore the natural flow

and reduce sedimentation in the lower creek, and Malibu Creek and Lagoon. Stream banks will be

stabilized using a bio-engineered revetment and replanted with native vegetation.

3.3 PROJECTS TO ERADICATE NON-NATIVE PLANTS FROM WETLANDS

A number of projects have been proposed, or are underway, to eradicate non-native/invasive plants

from several of the creeks that feed the wetlands along the shore of Santa Monica Bay and areas to

the south. Plants like the Giant Reed (Arundo donax) clog waterways, increase sedimentation, and

consume large quantities of water. Removal of these plants can help restore flow within these coastal

creeks and marshes to historic levels. Non-native plant eradication programs are currently underway

in lower Topanga Creek, Malibu Creek, and Solstice Creek (a tributary of Malibu Creek).

3.4 NEARSHORE COASTAL PROJECTS

Projects for enhancing nearshore coastal areas include restoring degraded habitat such as kelp beds

and rocky intertidal areas, and projects that establish new habitat such as the construction of artificial

reefs. The increased biological productivity resulting from these projects can be weighed against the

IM&E losses associated with the operation of coastal generating stations.

3.4.1 Restoration of Natural Resources in Rocky Intertidal Habitats in

Santa Monica Bay

The UCLA Institute of the Environment currently has funding from the Santa Monica Bay

Restoration Commission (as part of the Santa Monica Bay Restoration Plan) for a project to identify

the causes of degradation of the intertidal habitats in Santa Monica Bay. The project will identify,

evaluate, and recommend practical restoration techniques for these habitats.

3.4.2 Kelp Restoration

Santa Monica Bay Keeper has an ongoing kelp bed restoration project that has been partially funded

as part of the Santa Monica Bay Restoration Plan. Historically, the rocky northern (Malibu area) and

southern (Palos Verde peninsula only about 10 miles downcoast of the SGS) portions of the bay were

once covered by dense kelp forests. Over the last 50 years, the acreage of these beds has been greatly

reduced. Several kelp restoration projects, including the efforts of Santa Monica Bay Keeper, have

attempted, with some success, to return the kelp beds to their original extent. The techniques

employed include the removal of grazing herbivores (primarily sea urchins) and the introduction of

laboratory-reared kelp plants into areas where kelp coverage has declined. Kelp beds provide habitat

for numerous species of fish, invertebrates, and marine mammals. Increasing the size of the kelp beds

in Santa Monica Bay or the Palos Verde peninsula to the south of SGS, and the associated increase in

biomass that would accompany the restoration, could help offset IM&E losses due to operation of

coastal generating stations.

3.4.3 Artificial Reef

Several artificial reefs have been constructed along the coast of California, most notably the San

Clemente Artificial Reef (SCAR) that was built as part of the mitigation for the San Onofre Nuclear

Generating Station (SONGS) thermal discharge. SCAR was established in 1999 and its performance
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has been monitored since that time. The artificial reef modules have provided new substrate for giant

kelp and other algae. The reef and its associated kelp canopy have, in turn, provided new habitat for

fish and invertebrates.

3.4.4 Restocking of Affected Fish Species

Hubbs-Seaworld Research Institute (HSWRI) operates aquaculture research facilities in southern

California and Florida. Since 1983, the HSWRI has bred, tagged, and released over 650,000 white

seabass into southern California waters. The institute has also bred and released other fish species,

and is assessing the feasibility of breeding rockfish. The technology developed by the institute, as part

of their Ocean Resources Enhancement Hatchery Program, could potentially be used to restock

species, although the 316(b) regulations discourage a hatchery replacement approach.

3.5 PRELIMINARY RANKING/EVALUATION OF RESTORATION PROJECTS

A set of selection criteria was developed for ranking the prospective habitat restoration projects

previously described, or any other comparable projects that might be considered for implementation.

They include:

 Location  Cost effectiveness

 Nexus to IM&E effects  Ability to measure performance

 Basic need or justification for project  Success of comparable restoration

projects

 Nature and extent of ecological benefits  Time before benefits accrue

 Stakeholder acceptance  Technical feasibility

 Administrative considerations  Opportunities for leveraging of

funds/Availability of matching funds

 Consistency with ongoing resource agency

work and environmental planning

 Legal hurdles (e.g., permits, legal

access)

 Implementation costs  Duration of benefits

Depending upon the nature of a particular project, the relative importance and weighing of these

criteria may vary. As a general proposition, however, projects will be selected so as to maximize the

offset of IM&E effects for compliance with 316(b), and secondarily to optimize ecological benefits to

Santa Monica Bay/San Pedro Bay, or adjacent offshore areas within the Southern California Bight.

This process will ensure that the most effective projects are assigned the highest priority.

A description of each of the criteria is provided below:

Location

Ideally, the location of the project is in the same source water/ receiving water bodies that are affected

by the operation of the facility. Scores decrease as the distance between the project area and those

waterbodies increases. Projects that involve waterbodies and watershed areas that feed into the

affected areas can have a high ranking, but are not ideal.
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Nexustofacility’sIM&Eeffects

A project that enhances or replaces the species affected by the facility, in the waterbodies affected by

the facility would have the ideal nexus. As the project moves away from those species and locales, its

ranking decreases. The nexus is the relationship between the environmental impacts resulting from

the operation of the facility and the environmental benefits of the proposed project.

Basic need or justification for project

This category requires an evaluation of the need or justification for a proposed project. Restoration

projects that return wetland areas to their historic extent and replenish historic species that have been

depleted may be easily justified (high score). However, if the project requires that several blocks of

commercial property be razed to accommodate the project, it may require considerably more

justification. Other projects, like the establishment of artificial reefs where none formerly existed,

may be worthwhile, but will require some justification for their adoption (lowered score).

Technical feasibility

Is the technology or methodology utilized by the proposed project proven and effective? Has it, or

something similar, been used under similar conditions? Proven track record, or pie in the sky?

Stakeholder acceptance

Is the proposed project likely to have the support and approval of the regulatory agencies involved,

the owners and operators of the facility, and the local citizenry?

Nature and extent of ecological benefits

This is a category of magnitude. Does the project have a relatively narrow and limited ecological

benefit, such as increasing the population of a single species within a limited spatial context, or does

it benefit a large number of species (directly and indirectly) over an extensive area (higher ranking)?

Time before benefits accrue

If the proposed project is enacted, how much time will elapse before the benefits of the project

become evident. Projects that will demonstrate their resultant benefits in a short period of time will

rank higher in this category. However, projects that will have a large ecological benefit, but will

require an extended period of time to come to fruition, will offset their lower ranking in this category

with a higher ranking in the previous (nature and extent of ecological benefits) category.

Duration of benefits

Projects with environmental benefits that continue over a long period of time will receive a higher

ranking than those with short-term, transient, benefits. This category works in conjunction with the

two previous categories.

Success of comparable restoration projects

Thiscategoryissimilartothe“TechnicalFeasibility”category,butgoesastepbeyondfeasibilityto

the question of the success or failure of comparable projects. High rankings are given to projects that

are comparable to successful projects, low rankings are given to projects comparable with failed

efforts, and neutral rankings are given to projects lacking comparable examples (return to the question

of feasibility).
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Consistency with ongoing resource agency work and environmental planning

Does the proposed project conflict with any ongoing resource agency work or environmental

planning? Projects without conflicts, which mesh well with ongoing projects and policy, will receive

the highest rankings. Projects that are inconsistent with current environment policy and ongoing

projectswillreceivealowerranking(seealso“Basicneedorjustificationforproject”and“Legal

hurdles”).

Legal hurdles (permitting, etc.)

In this category, projects that face significant legal hurdles, such as those that require extensive

permitting for their implementation, will receive lower ranking than those projects not hindered by

such requirements. The cost of overcoming these hurdles (time and money) should also be

incorporatedintotheevaluationoftheprojectinothercategories(“Implementationcost,”“Time

before benefits accrue,”and“Basicneedorjustificationforproject”).Providing additional funding

for an ongoing project that has already passed these hurdles would also receive a high ranking.

Implementation costs

This category is fairly straightforward, but requires some additional information about the magnitude

of the IM&E impacts to be offset for a proper evaluation of any potential project. The environmental

benefits accrued by a given project need to be weighed against the impacts that need to be offset

(“Cost/Benefit”).

Funding opportunities (matching funds, leveraging of funds, etc.)

Ongoing projects will do well in this category since they are already receiving at least some funding.

Many potential restoration projects have popular support, which can help with additional funding as

well as lending support in categorieslike“Basicneedorjustificationfortheproject,”“Stakeholder

support,”andeven“Legalhurdles.”Newer,moreinnovative,projectsmayhavefewerfunding

opportunities and would rank lower.

Ability to measure performance

Can the beneficial environmental effects of the proposed project be measured in some fashion that

relates to offsetting the impacts of the operation of the facility in question? Projects with more

qualitative, less tangible benefits would score lower in this ranking. Certain projects lend themselves

more easily to this category than others. The restocking of an area with fish can readily be assessed by

noting the number of fish introduced, the number surviving, the number reproducing, etc. Artificial

reefs and restored kelp beds can be surveyed to record species recruitment and the associated increase

in biomass. Restored wetlands may be more difficult to assess because of their complexity, including

terrestrial and aquatic habitats, nursery areas, birds, mammals, fish, and invertebrates, transient

species, etc. The performance of projects that restore watershed areas is even more difficult to assess

because of the indirect nature of many of their benefits to the areas directly impacted by IM&E

losses.

Cost / Benefit

How much bang-for-the-buck can be hard to gauge for many projects. The cost may be relatively easy

to calculate, but how do you measure all of the benefits of a project like the restoration of a historic

wetland(see“Abilitytomeasureperformance”)?Rankinginthiscategory may be somewhat

subjective with both the cost and benefits of a project placed somewhere along a gradient that ranges

from small to large.
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Administrative considerations

How large are the administrative needs of a potential project. This includes taking the project through

any required approval/permitting process, implementing the project, and administering it through to

completion. Projects with limited need for oversight would score higher than projects requiring a

large administrative infrastructure.

Using a five point ranking system, each of the projects described in Section 3 was scored for the

criteria listed above. A ranking of 1 represents a very poor fit in any category; 5 an excellent fit. As

an example, a project located in Alamitos Bay, in very close proximity to SGS, would be ranked 5 for

its Location, but if it faced significant issues concerning regulatory permitting for the project, it might

rank a 2 for Legal Hurdles.

Rankings for the individual projects are shown in Table B-1. No rankings are provided for

Implementation Costs or Cost Effectiveness at this time, since the magnitude and duration of the

projects will be dependent upon the results of the LADWP IM&E studies.

An additionalaspectnotconsidered in the criterion of‘Opportunities for leveraging of

funds/Availabilityofmatchingfunds’isthepotentialforrestorationcoststobesharedamongthe

power generating facilities located on the coast in Santa Monica Bay or in the larger Los Angeles

Basin coastal area. This would increase the scores for wetland projects in Orange County area that

are closer to the power generating facilities located in the Los Angeles/Long Beach Harbor Area and

facilities further south.

3.5.1 Results of Initial Rankings

The results of the initial ranking of projects indicate that the larger wetlands restoration, kelp bed

restoration, and artificial reef projects would be the most suitable for further evaluation. The projects

with the highest ranking were the Ballona Wetlands, the Bolsa Chica Lowlands, and the Huntington

Beach Wetlands projects. The Ballona Wetlands project scored highly because it is located only 4

miles upcoast of SGS, and is the only remaining large coastal wetland in Los Angeles County. In

contrast, the Los Cerritos Wetlands, located immediately adjacent to HnGS, did not score as high

because of multiple zoning issues and the presence of large quantities of hazardous materials that

were disposed in the area in the past. These projects, or other wetland projects, could be combined

with one of the open coastal projects such as the establishment of an artificial reef to provide

restoration credits for both estuarine and coastal species.
Attachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

Draft 12

TABLE B-1. QUALITATIVE RANKING, WITH 1 BEING LOWEST AND 5 BEING HIGHEST OF POTENTIAL RESTORATION PROJECTS FOR

OFFSETTING SCATTERGOOD GENERATING STATION IM&E LOSSES.

RESTORATION PROJECT ZUMA

WETLANDS

MALIBU

LAGOON

TOPANGA

LAGOON AND

CREEK

BALLONA

WETLANDS

LOS

CERRITOS

WETLANDS

BOLSA CHICA

LOWLANDS

HUNTINGTON

BEACH

WETLANDS

UPPER

NEWPORT

BAY

LAS

VIRGENES

CREEK

NON-NATIVE

PLANT

ERADICATION

SANTA MONICA

BAY ROCKY

INTERTIDAL

SANTA MONICA

BAY KELP BEDS

ARTIFICIAL

REEF

EVALUATION CRITERIA

Location 5 5 5 5 4 4 4 4 3 3 5 5 5

Nexus to SGS Impacts 4 4 4 5 4 4 4 4 3 3 3 5 5

Basic Need or Justification For

Project 2 4 3 5 4 4 4 5 3 3 3 4 3

Nature and Extent of Ecological

Benefits 2 3 2 5 4 3 3 4 2 2 3 5 5

Stakeholder Acceptance 5 5 5 5 5 5 5 5 5 5 5 5 4

Administrative Considerations 4 4 4 4 3 4 4 4 4 4 2 3 2

Consistency With Ongoing

Resource Agency Work and

Environmental Planning 5 5 5 5 5 5 5 5 5 5 4 5 4

Implementation Costs No Data No Data No Data No Data No Data No Data No Data No Data No Data No Data No Data No Data No Data

Cost Effectiveness No Data No Data No Data No Data No Data No Data No Data No Data No Data No Data No Data No Data No Data

Ability to Measure Performance 3 3 3 4 4 4 4 4 2 2 2 3 5

Success of Comparable Projects 3 3 3 4 4 4 4 4 3 3 2 3 5

Time Before Benefits Accrue 3 3 3 3 3 3 3 3 2 2 2 4 4

Technical Feasibility 3 3 3 4 3 4 4 4 3 3 2 3 5

Funding Opportunities

(matching funds, leveraging of

funds) 4 4 4 4 4 4 4 4 4 4 4 4 3

Legal Hurdles (permitting, etc.) 4 4 4 4 3 4 4 4 4 4 3 4 2

Duration of Benefits 3 3 3 5 5 5 5 5 3 3 3 3 5

TOTAL 50 53 51 62 55 57 57 59 46 46 43 56 57
Attachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

Draft 13

4.0 CONCLUSIONS AND RECOMMENDATIONS

An initial screening of potential projects in the vicinity of the LADWP power plants using the set of

criteria described in this report was used to determine that wetlands restoration, kelp bed restoration,

and artificial reef projects would be the most suitable for further evaluation. Restoration projects

associated with the Ballona Wetlands, Upper Newport Bay, Bolsa Chica Lowlands and Huntington

Beach Wetlands received the highest rankings using the criteria previously described. Located only 4

miles upcoast of SGS, the Ballona Wetlands scored highly based on its location. The Ballona

Wetlands are also the only remaining large coastal wetlands in Los Angeles County. There are active

groups involved with the preservation of the wetlands and acquisition of additional lands to expand

the wetlands to its historical boundaries. These groups and projects associated with the Ballona

Wetlands provide opportunities for funding similar to the approach used at Elkhorn Slough for the

Moss Landing Power Plant where money was transferred to the Elkhorn Slough Foundation for the

expansion and preservation of wetland habitat that offset entrainment losses from the power plant.

The proposed restoration of the Los Cerritos Wetlands, adjacent to the HnGS, has the potential to be a

viable restoration option for any or all of the LADWP facilities. However, as cited in the final report

of the City of Long Beach, Los Cerritos Wetlands Study Group (available as a downloadable pdf file

at http://www.longbeach.gov/plan/pb/cpd/los_cerritos.asp), there are several pressing issues that need

to be dealt with prior to proceeding with any of the proposed restoration projects. These issues

include the numerous and varied zoning and jurisdictional concerns related to the area of the former

wetlands,andthearea’shistoryofuseasahazardouswastedisposalsite.Theseconcerns were

reflected in the lower ranking of this restoration option in comparison with the Ballona Wetlands.

A major wetlands restoration project at a location like the Ballona Wetlands could be supplemented

with a coastal project to compensate for losses to marine coastal fishes. The projects that received the

highest ranking using the criteria in this report were kelp ked restoration and artificial reefs. The

SONGS is using an artificial reef as mitigation for the effects of the thermal discharge on kelp beds

and associated communities. Studies at a pilot-scale artificial reef being used in the design of the final

full-scale project show that the artificial reef is performing similar to natural reefs in the area.

Development of giant kelp (Macrocystis spp.) on an artificial reef would provide the added benefit of

increasing the area of kelp habitat, an important habitat-forming community in the nearshore areas at

the north and south headlands of Santa Monica Bay. Kelp beds provide habitat for a wide variety of

invertebrates and fishes. An artificial reef project in Santa Monica Bay benefits from all of the work

that has been completed for the SONGS reef project. It is also relatively easy to demonstrate the

benefits from an artificial reef, since the SONGS project has shown that communities develop fairly

rapidly on the new habitat.
Attachment C Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

Draft 1

ATTACHMENT C -

VELOCITY CALCULATIONS

The following is a summary of SGS velocity flow calculations.

Data:

Flow (Q):

Units 1 & 2: 173.8 cfs (each)

Units 3: 418.8 cfs

Total: 766.5 cfs

Water Elevation: El. 0.0 ft

Velocity Cap Diameter: 32.5 ft

Opening Height: 5.0 ft

Intake Pipe Diameter: 12.0 ft

Intake Pipe Area: 113.0 ft2

Number of Intake Pipes: 1

Screen Width: 6.0 ft

Number of Bays:

Units 1 &2: 2 per unit

Unit 3: 4

Screenhouse Invert: El. -23.5 ft

Formula Used

( )

( )

( )

A area

Q flow V velocity 

Calculations

1.5 /sec

5 *32.5 *

766.5

( ) ft

ft ft

cfs V Velocitycap  



6.8 /sec

113.0

766.5

( )

2

ft

ft

cfs V Intakepipes  

0.6 /sec

2 * 6 * (0.0 23.5 )

173.8

( 1& 2 ) ft

ft ft ft

cfs V Units screens 





0.7 /sec

4 * 6 * (0.0 23.5 )

418.8

( 3 ) ft

ft ft ft

cfs V Unit screens 




Attachment D Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

1

ATTACHMENT D -

FISH MORPHOMETRY AND SCREEN MESH HEADLOSS

The following information on fish morphometry was developed by LMS as part of a NJPDES Permit

specialconditionforPSEGServicesCorporation’sSalemGeneratingStation6.

This study was designed to use physical measurements from preserved ichthyoplankton to compute

the expected size of larval fish retained by plankton nets of various mesh sizes. “...Expectations of

the size of organisms to be retained by a given mesh size can be developed from the physical

dimensions of the organism. This may be done by first relating the greatest cross-sectional dimension

(such as skull width or other measures of body girth) to overall fish length. Then, the greatest mesh

dimension is computed, typically the mesh diagonal. Smith et al. (1968) found that the maximum

cross-sectional diameter of the organism must be greater than the mesh diagonal if it is to be fully

retained. For a given cross-sectional diameter and associated standard deviation, the percentage

retained and excluded is calculated by integration under a normal curve. Examples of this type of

analysis may be seen in Vannucci (1968), Lenarz (1972), Colton et al. (1980), Turnpenny (1981),

Schneeberger and Jude (1981) among others. Results of this analysis may then be used to develop

working guidelines for the minimum size necessary for retention of each species....”The only

exception is the data for naked goby, which were developed from scale-drawings by Alden using the

LMS model. The reported entrainment and impingement probabilities are for 0.5 mm mesh screens

and are provided as an illustration of the effect of length/head capsule depth (HCD) on entrainment

and impingement. The reported HCD at body length was used to predict the HCD for SGS species.

The series 3 and 4 categories refer to entrainment and impingement, respectively.

The screen mesh headloss assessment was prepared by Alden with data provided by Johnson Screens

and Siemens Screens.

6

Public Service Enterprise Group. (2002). Salem Generating Station, NJPDES Permit #NJ0005622,

Custom Requirement G.9.b.ii, Entrainment Extrusion Study, Task #1, Morphometric Analysis.
Attachment D Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

2

Atlantic Silverside

Eggs:

Probability Probability

Entrainment Impingement

0.00000000 1.00000000

Larvae

length ln (length) ln (HCD) HCD Probability Probability

(mm) (mm) Entrainment Impingement

1 0 -2.17238 0.113907 1 0

2 0.6931472 -1.47022 0.229876 1 1.9867E-12

3 1.0986123 -1.05948 0.346636 0.99946385 0.00053615

4 1.3862944 -0.76806 0.463913 0.74820565 0.25179435

5 1.6094379 -0.54201 0.581576 0.08860428 0.91139572

6 1.7917595 -0.35732 0.699547 0.00135686 0.99864314

7 1.9459101 -0.20117 0.817775 5.5983E-06 0.9999944

8 2.0794415 -0.0659 0.936224 1.0692E-08 0.99999999

9 2.1972246 0.053413 1.054866 1.3169E-11 1

10 2.3025851 0.160144 1.17368 1.2815E-14 1

11 2.3978953 0.256693 1.292648 1.1191E-17 1
Attachment D Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

3

Atlantic croaker

Eggs:

Probability Probability

Entrainment Impingement

0.00354797 0.99645203

Larvae

length ln (length)

ln

(HCD) HCD Probability Probability

(mm) (mm) Entrainment Impingement

1 0 -1.9015 0.149345 1 0

2 0.6931472 -1.1023 0.332107 1 4.5773E-12

3 1.0986123 -0.6348 0.530043 0.16540446 0.83459554

4 1.3862944 -0.3031 0.738525 3.9953E-11 1
Attachment D Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

4

Bay anchovy

Eggs:

Probability Probability

Entrainment Impingement

0.00007334 0.99992666

Larvae

length ln(length) ln(HCD) HCD Probability Probability

(mm) (mm) Entrainment Impingement

1 0 -1.69755 0.183132 1 3.5926E-10

2 0.6931472 -1.2165 0.296265 0.99933809 0.00066191

3 1.0986123 -0.93511 0.392543 0.9311524 0.0688476

4 1.3862944 -0.73546 0.479286 0.60240373 0.39759627

5 1.6094379 -0.5806 0.559565 0.24494069 0.75505931

6 1.7917595 -0.45406 0.635041 0.07122037 0.92877963

7 1.9459101 -0.34708 0.706746 0.01687337 0.98312663

8 2.0794415 -0.25441 0.775371 0.00355533 0.99644467

9 2.1972246 -0.17267 0.841413 0.00070377 0.99929623

10 2.3025851 -0.09955 0.905243 0.00013543 0.99986457

11 2.3978953 -0.03341 0.967145 2.5885E-05 0.99997411

12 2.4849066 0.026979 1.027346 4.982E-06 0.99999502

13 2.5649494 0.152558 1.16481 1.0607E-07 0.99999989

14 2.6390573 0.281506 1.325124 1.1194E-09 1

15 2.7080502 0.401553 1.494144 9.342E-12 1

16 2.7725887 0.51385 1.671716 6.5628E-14 1

17 2.8332133 0.619337 1.857696 4.0709E-16 1

18 2.8903718 0.718793 2.051955 2.3135E-18 1
Attachment D Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

5

Atlantic menhaden

Eggs:

Probability Probability

Entrainment Impingement

0.00000000 1.00000000

Larvae

length ln(length) ln(HCD) HCD Probability Probability

(mm) (mm) Entrainment Impingement

1 0 -0.46918 0.625518 0.03208407 0.96791593

2 0.6931472 -0.18776 0.828816 1.4783E-05 0.99998522

3 1.0986123 -0.02314 0.977127 1.5362E-08 0.99999998

4 1.3862944 0.093661 1.098187 3.9487E-11 1

5 1.6094379 0.184257 1.202325 2.0644E-13 1

6 1.7917595 0.258279 1.2947 1.8748E-15 1

7 1.9459101 0.320865 1.378319 2.6405E-17 1
Attachment D Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

6

Naked goby

Eggs:

Probability Probability

Entrainment Impingement

0.00000000 1.00000000

Larvae

length ln(length) ln(HCD) HCD Probability Probability

(mm) (mm) Entrainment Impingement

1 0 -1.40758 0.244734 1 1.5477E-13

2 0.6931472 -0.82465 0.43839 0.9101756 0.0898244

3 1.0986123 -0.48365 0.616528 0.01626992 0.98373008

4 1.3862944 -0.24171 0.785284 2.0475E-06 0.99999795

5 1.6094379 -0.05405 0.947388 3.4819E-11 1

6 1.7917595 0.099286 1.104382 3.0815E-16 1

7 1.9459101 0.228926 1.25725 2.5064E-21 1
Attachment D Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

7

Wire-mesh screen head loss characteristics

Assumptions for head loss calculations:

Screen approach velocity at 1 feet/sec

Through-flow screen (two screen mesh baskets in flow path)

Head loss coefficients from M. Papworth 1972

Screen characteristics:

Screen

Mesh

Wire

spacing

(in)

Wire

dia.

(in)

Wire

dia.

(mm)

opening

(mm)

Open

area

Backup

screen

(1"

mesh)

combined

open area

with 1" backup screen

3/8" mesh 0.444 0.08 2.0 9.3 67% no 67%

10 mesh 0.100 0.025 0.64 1.9 56% yes 45%

18 mesh 0.056 0.017 0.43 1.0 48% yes 39%

30 mesh 0.033 0.012 0.30 0.5 41% yes 33%

50 mesh 0.020 0.009 0.23 0.3 30% yes 24%

70 mesh 0.014 0.0065 0.17 0.2 30% yes 24%
Attachment D Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

8

LITERATURE CITED

Colton, J.B., Jr., J.R. Green, R.R. Byron, and J.L. Frisella. 1980. Bongo net retention rates as

effected by towing speed and mesh size. Can. J. Fish. Aquat. Sci. 37:606-623.

Lenarz, W.H. 1972. Mesh retention of Sardinops caerulea and Engraulis mordax by plankton nets.

Fish. Bull. U.S. 70:839-848.

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. Trans. Amer. Fish. Soc. 110:246-252.

Smith, P.E., R.C. Counts, and R.I. Clutter. 1968. Changes in filtering efficiency of plankton nets

due to clogging under tow. J. Cons. perm. int. Explor. Mer.32: 232-248.

Turnpenny, A.W.H. 1981. An analysis of mesh sizes required for screening fishes at water intakes.

Estuaries, 4(4):363-368.

Vannucci, M. 1968. Loss of organisms through the meshes. In D.J. Tranter (ed.), Part I, Review on

zooplankton sampling methods, p. 77-86. UNESCO Monograph. Oceanography. Methodology. 2,

Zooplankton Sampling
Attachment E Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

1

ATTACHMENT E -

POTENTIAL FISH RETURN CLEANING SYSTEMS

Fish and debris removed from fine-mesh traveling water screens with fish protection or MIS modules

would have to be conveyed back to the ocean. To prevent re-impingement, the return line will have to

transport fish and debris to the near shore region, well away from the intake. This return location was

selected as returning fish to the discharge pipe, the current procedure, is expected to increase mortality

due to thermal stress. Once removed from the screens, fish and debris would flow into a pipe that would

run under the beach out to beyond the low tide line. Additional water would need to be added to the

return line to provide the fish removed from the screens a 6 inch water cushion. A pipe was selected to

allow the return line to be buried under the beach. A small rock jetty may need to be constructed around

the exit of the pipe to prevent erosion around the discharge location.

Alden has identified two options for cleaning the pipe portion. These options are: a heat treatment or two

return pipes which would be used on an alternating basis to allow drying of the pipes. The constraints

and benefits of each option are listed in the following table.

Criteria Heat Treatment Two Pipes

Construction Concerns The existing discharge lines

would need to be tapped. A

pump would be required to

transport water to the return

line.

Twice as much pipe with

isolation valves.

Construction Impacts on Plant

Operation

Would require a unit to be

shutdown while the discharge is

tapped. Could be completed

during a scheduled outage.

None.

Impacts on Plant Operation Heat treatments would need to

be timed to coincide when units

are operating at maximum inlet

temperature and plant output.

None.

Impacts on Screen Operation None. None.

Impacts on Survival No survival during heat

treatment.

None.

Reliability If return pipe or hot water line

fails there is no redundancy.

If one return pipe fails, the

second one can be brought into

operation rapidly.

Installation Cost1$213,000 $279,000

O&M Costs1$18,000 $19,000

1. Costs are in 2006 and are based on the same assumptions as the costs in the cost section of this Addendum

The same methods used to clean the fish return for the modified traveling screen options would be

applicabletothefishreturnrequiredforModularIncludedScreens.ThefishreturnpipefortheMIS’s

would be the same length as the traveling screen return but would require a larger piper, to accommodate

the required bypass flow. The preceding table is valid for MIS return, except for the costs. For the MIS

return system the cost for both cleaning options would be very similar but higher than those in the table.
Attachment E Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

2

Estimated from Alden Database

Alternative Construction

Costs

(2006 $)

Replacement Power

During Shutdown

(MWh)

Total Capital

Cost (2006 $)1

O&M

Costs

(2006 $)

Lost

Generation

(MWh) 2

Annualized

Capital Costs

(2006 $)3

Incremental

Annualized

O&M Costs

(2006 $)1, 2

Total

Incremental

Annualized

Costs

(2006 $)

Use reclaimed water for

Unit 3

$16,996,000 0 $16,996,000 $0 0 $2,420,000 $0 $2,420,000

Use reclaimed water for

Unit 3 and either Unit 1 or

2

$25,022,000 0 $25,022,000 $0 0 $3,563,000 $0 $3,563,000

Use reclaimed water to

provide make-up water

for closed-cycle cooling.

$1,184,000 0 $1,184,000 $0 0 $169,000 $0 $169,000
Attachment F Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

1

ATTACHMENT F -

USE OF RECLAIMED WATER AT SGS

SGS may be able to use reclaimed water to supplement the existing circulating water needs.

SGS currently withdraws about 766 cubic feet per second (cfs) (495 million gallons per day [MGD])

of circulating water, Units 1 & 2 each use 174 cfs (112 MGD) and Unit 3 uses 419 cfs (271 MGD).

The Hyperion Wastewater Treatment Facility (Hyperion), which is located adjacent to SGS, treats

about 560 cfs (362 MGD) of water per day. After secondary treatment, this water is discharged about

5 miles offshore. Hyperion has a dry weather capacity of 696 cfs (450 MGD) and a wet weather

capacity of 1,315 cfs (850 MGD). Alden has assumed that all the capacity above 450 MGD is

untreated bypass water and would not be available for use at SGS.

Using the daily average daily flow from Hyperion, SGS would be able to operate Unit 3 completely

on reclaimed water and either Unit 1 or 2 could run on 80% reclaimed water on a daily basis. These

two options would result in a 55% and 73% reduction in flow, respectively, from full once-through

cooling. If the average daily flow at Hyperion increases another 21 MGD, SGS would be able to

operate Units 3 and either 1 or 2 completely on reclaimed water providing a 77% reduction in flow

from the existing once through operations.

If SGS were to switch to closed-cycle cooling reclaimed water could be used provide make-up water

for the cooling towers. The amount of make-up water needed using reclaimed water would be less

than that if seawater was used due to the reduced number of concentration cycles required.

Additionally, reclaimed water would eliminate potential for salt drift. Alden estimates that

approximately 40 cfs of reclaimed water will be need to provide make-up water for all three units

Using reclaimed water at SGS would have several drawbacks.

 Availability

 The flow of reclaimed water is not consistent and during low flow periods there may not

be enough water available to adequately cool the units.

 The actual amount of water available for use at SGS is not known.

 The existing once-through system would have to be maintained to provide circulation

water in the event that Hyperion cannot provide sufficient flow.

 Delivery

 An approximately 0.75-mile-long delivery pipe/tunnel from the Hyperion discharge line

would have to be constructed.

 The Hyperion outfall my need to be shut down during the final connection to SGS, to

prevent spillage of the treated water.

 Locating the delivery pipe may interfere with other infrastructure already in place.

 A bypass would be needed to allow Hyperion to discharge when SGS is not operating.

 Discharge

 The SGS thermal discharge outfall is not permitted to discharge reclaimed water.

 Any reclaimed water used at the facility would have to be piped back to the Hyperion

discharge pipes for offshore discharge.
Attachment F Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

2

 If reclaimed water was used to supplement the existing flow, the combined flow would

need to be returned to the Hyperion discharge pipe. The ability of the Hyperion line to

handle the additional volume would have to be considered.

 The plume associated with closed-cycle cooling could contain particulate matter and

trace pollutants and may fall under the Clean Air Act.

Appraisal level costs for using reclaimed water were calculated for SGS. Three potential options

using reclaimed water were looked at. The first option is to divert enough water for Unit 3, only. The

second option is to divert enough reclaimed water to supply the full flow for Unit 3 and either Unit 1

or 2. The final option is to use reclaimed water as make-up water for closed-cycle cooling. The

actual use of reclaimed water would be heavily dependent on the amount of water available and the

compliance method chosen by LADWP. The costs for all the options are based on (two) 4,000 ft

pipes which would allow the water used by SGS to be returned to the Hyperion outfall pipe. These

costs use the same methodology as the costs calculated in the 2004 report.