## F I N A L R E P O R T



# A DDENDUM 

# T O 

# E VALUATION OF THE 

# S CATTERGOOD 

# G ENERATING 

# S TATION WITH 

# R ESPECT TO THE 

# C LEAN 

# W ATER 

# A CT 

# S ECTION 

# 316( b ) R EQUIREMENTS 

# P ROVIDING 

# A C URRENT 

# A SSESSMENT OF 

# A LTERNATIVE 

# T ECHNOLOGIES AND 

# O PERATIONAL 

# M EASURES

Pr epared 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 , 2007Addendum t o t he 316(B) Evaluation o f t he Scattergood Generating Station

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## TABLE OF CONTENTS S ECTION 

## P AGE 

## 1.0 Introduction ................................ ................................ ....................... 1 - 1 2.0 Additional Information Currently Available ................................ ... 2 - 1 2.1 A DDITIONAL T ECHNOLOGIES
................................ ................................ ................. 2

- 1 2.2 IMPINGEMENT M ORTALITY AND E NTRAINMENT C HARACTERIZATION
................... 2

- 2 2.3 C O STS
................................ ................................ ................................ ................... 2

- 2 2.4 S ECOND C IRCUIT C OURT D ECISION
................................ ................................ ....... 2

- 3 

## 3.0 Entrainment Reduction Options ................................ ....................... 3 - 1 3.1 F INE
- MESH M ODIFIED T RAVELING S CREENS
................................ .......................... 3

- 1 3.2 N ARROW
- SLOT C YLINDRICAL W EDGEWIRE S CREENS
................................ ............ 3

- 3 3.3 M ODULAR INCLINED S CREENS
................................ ................................ .............. 3

- 3 3.4 F LOW R EDUCTION
................................ ................................ ................................ . 3

- 4 3.5 C LOSED
- CYCLE C OOLING
................................ ................................ ...................... 3

- 5 3.6 A DDITIONAL T ECHNOLOGIES
................................ ................................ ................. 3

- 5 

## 4.0 Impingement Mortality Reduction Options ................................ ..... 4 - 1 4.1 C OARSE
- MESH M ODIFIED T RAVELING S CREE NS
................................ .................... 4

- 1 4.2 W IDE
- SLOT C YLINDRICAL W EDGEWIRE SCREENS
................................ .................. 4

- 1 4.3 C OARSE
- MESH B ARRIER N ET
................................ ................................ ................. 4

- 2 4.4 M ODULAR INCLINED S CREENS
................................ ................................ .............. 4

- 2 4.5 F LOW R EDUCTION
................................ ................................ ................................ . 4

- 2 4.6 C LOSED
- CYCLE COOLING
................................ ................................ ....................... 4

- 3 4.7 A DDITIONAL T ECHNOLOGIES
................................ ................................ ................. 4

- 3 

## 5.0 Cost Update ................................ ................................ ........................ 5 - 1 6.0 Data Gaps and Uncertainties ................................ ............................ 6 - 1 7.0 Conclusions ................................ ................................ ........................ 7 - 1Addendum t o t he 316(B) Evaluation o f t he Scattergood Generating Station

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### L IST OF 

### T ABLES T ABLE 2

- 1. P ERTINENT P ROJECT D ATA (R EVISED T ABLE 2

- 1 FROM THE I NITIAL R EPORT )

.............. 2

- 5 T ABLE 2

- 2. C OMPARISON OF P ERCENT C OMPOSITION OF E NTRAINED LARVAE LENGTHS C OLLECTED AT SGS

................................ ................................ ................................ ................ 2

- 7 T ABL E 2

- 3. INITIAL S CREENING OF F ISH P ROTECTION A LTERNATIVES AT SGS (R EVISED T ABLE 3

- 1 FROM THE I NITIAL E VALUATION )

................................ ................................ ........... 2

- 8 T ABLE 3

- 1. P REDICTED H EAD C APSULE D EPTH (HCD) OF R EPRESENTATIVE E NTRAINED LARVAE C OLLECTED AT SGS

................................ ................................ ................................ .. 3

- 2 T ABLE 5

- 1. A LDEN ’ S A PPRAISAL LEVEL C OSTS OF E VALUATED A LTERNATIVES
............................ 5

- 2 T ABLE 6

- 1. D ATA G APS AND U NC ERTAINTIES FOR A LTERNATIVES
................................ ................. 6

- 2 T ABLE B

- 1. Q UALITATIVE R ANKING , WITH 1 B EING L OWEST AND 5 B EING H IGHEST OF P OTENTIAL R ESTORATION P ROJECTS FOR O FFSETTING S CATTERGOOD G ENERATING S TATION IM&E L O SSES
. ................................ ................................ ................................ ........... 12 

### L IST OF 

### A TTACHMENTS ATTACHMENT A

- S UMMARY O F 2004 E VALUATION O F SGS ATTACHMENT B

- LADWP R ESTORATION O PTIONS ATTACHMENT C

- F LOW C ALCULATIONS ATTACHMENT D

- F ISH M ORPHPMETRY A ND S CREEN M ESH H EADLOSS ATTACHMENT E

- U SE O F R ECLAIMED W ATER A T SGSAddendum t o t he 316(B) Evaluation o f t he Scattergood Generating Station

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### L IST OF 

### A CRONYMS 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 Modul ar Inclined Screens mm millimeter MW megawatts MWh megawatt hour NOAA National Oceanic and Atmospheric Administration O&M Operating and Maintenance VSD Variable Speed DrivesAddendum t o t he 316(B) Evaluation o f t he Scattergood Generating Station

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- 1 

## 1.0 INTRODUCTION In December 2004, Alden Research Laboratory, Inc. (Alden) , u nder contract to the Electric Power Research Institute (EPRI) , developed a report e nt i t l e d “ E v a l u at i o n o f t h e Scattergood Generating S t a t i o n w i th r e s p e c t t o th e E n v i r o n m e n t a l P r o t e c t i o n A g e n c y ’ s 3 1 6 ( b ) R u l e s f o r E x i s t i n g F a c i l i t i e s ” for the Los Angeles Dep artment 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 t hat 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 standa rds. 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. T he 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 wedgewi re 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 unsuit able 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 A ddendum to the 2004 r eport. 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, M BC Applied Environmental (MBC), Tenera Environmental, Inc. (Tenera) , and URS Corporation (URS).Addendum t o t he 316(B) Evaluation o f t he Scattergood Generating Station

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- 1 

## 2.0 ADDITIONAL INFORMATI ON CURRENTLY AVAILAB LE T h e f o l l o w i n g n e w i n f

o rm at i o n h a s b e e n a s s e s s e d a s i t r e l a t e s t o A l d e n ’ s o r i g i n a l e v a l u a t i o n :

 Additional technologi es 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 A DDITIONAL 

### T ECHNOLOGIES I n t h e 2 0 0 4 r e p o r

t , th e r e w e r e f

o ur t e c h n o l o g i e s c h a r a c t e r i z e d a s “ e m e r g i n g t e c h n o l o g i e s ” :

 B e a u dr e y ’ s F i s h P r o t e c t i on System (FPS);

 Filtrex Filter Candles;

 Debris and Organism Collect ion (DOC) system ; and

 G e i g e r ’ s M u l t i

- Disc Screening System

. Currently, the Filtrex Filter Candles have not been tested , and research on the DOC was discontinued after limited laboratory te sting. The original FPS has also not been tested. However, a variation of the original system that u t i l i z e s c i r c u l a r r o t at i n g s c r e e n s w i th a f i s h “ s c o o p ” h a s b e e n i n s t a l l e d a t o n e facility and is currently being tested. Therefore, the re is no new inform ation 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 Gene rating Station and was the subject of a one

year 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 technol ogy 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 avai lable 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 avail able at this time is 1.75 millimeters ( mm )

. T h

u s , t h i s t e c h n o l o g y h a s th e s am e “ l i m i t a t i o n ” a s th e M o du l a r In c l i n e d S c r e e n (MIS) system in excluding only larger entrained organisms and , therefore , would not meet entrainment performance standards for SGS

.Addendum t o t he 316(B) Evaluation o f t he Scattergood Generating Station

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- 2 Two new currently available screening technologies ( i.e., Hydrolox and Geiger screens) can be c o n s i d e r e d i n th e s a m e c at e g o r y a s R i s t r o p h s c r e e n s . B o th o f th e s e s y s t e m s f un c t i o n o n th e “ tr a

p a n d tr a n s f e r ” c o n c e p t a

n d r e q u i r e th e s a m e t y

p e o f f i s h a n d d e bris 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 entrainable

sized organism s 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 S creen (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 di vergent 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 I MPINGEMENT 

### M ORTALITY AND 

### E NTRAINMENT 

### C HARACTERIZATION Although the relativ e 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 Pac ific sardine

. The 2006 impingement was dominated by Pacific sardine. This most current impingement data do not c h a n g e A l d e n ’ s s e l e c t i o n o f a p p r o p r i a t e t e c hn o l o g i e s f o r c o n s i d e r at i o n at SGS

. E ntrainment 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 9 3

- 100% (depending on species) of entrained o r g a n i s m s w e r e “ p r e - tr a n s f o rm a t i o n ” s t a g e . T h a t i s , t h e v a s t m a j o r i ty o f entrained fish were less than 1 2 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 imp ingement 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 t his claim is rejected by the permitting agencies. T h e s e r e s u l t s d o n o t a l t e r A l d e n ’ s s e l e c t i o n o f ap p r o p r i at e t e c hn o l o g i e s f o r c o n s i d e r at i o n i n r e d

u c i n g entrainment at SGS . As discussed in Section 3, the overall efficacy of any entrainment reduction tech nology is mitigated by the predominance of such early life history stages. 

### 2.3 C OSTS 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 A ddendum (i.e.,Addendum t o t he 316(B) Evaluation o f t he Scattergood Generating Station

2

- 3 Table 6

- 3 from 2004 report)

. An adjustment factor of 1.12 1 was used to account for inflation and the price per megawatt hour ( MWh ) was increased from $40/MWh to $50/MWh 2

. For technologies that were evaluated fur ther in this Addendum , the costs presented in Table 5

- 1 have been modified to reflect the updated evaluations. 

### 2.4 S ECOND 

### C IRCUIT 

### C OURT 

### D ECISION The Court issued its Decision on the Phase II Rule on January 27, 2007 . This Decision ha d significant impacts on the compliance alternatives and options discussed in the 2004 r eport. The major components of the Decision are:

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

- Benefit Test, are u nlawful and cannot be used for compliance;

 The Court remanded to U.S. Environmental Protection Agency ( EPA ) the determination of Be st Technology Available (BTA); and

 The Court also remanded to EPA the Cost

- Cost Test and Technology Installation and Operatio n Plan du e t o E P A ’ s f a i l u r e t o p r o v i d e a d e qu a t e o p p o rt u n i t y f o r p ub l i c r e v i e w a

n d 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 ad verse environmental impacts associated with closed

- cycle cooling and impacts to energy production and efficiency. A s e c o n d m a

j o r c o mp o n e nt o f th e D e c i s i o n i s a r e q u i r e m e nt t o u s e th e “ b e s t p e r f o rm i n g ” t e c hn o l o g y . The Court determined that if EPA chose t o u s e p e r f o rm a n c e s t a n d a r d r a n g e s , a f

a c i l i t y ’ s d e c i s i o n could no longer be based on which technology was most cost

- effective. Rather , th e “ b e s t p e r f o rm i n g ” t e c h n o l o g y i n th e ap p r o p r i at e p e r f o rm a n c e s t a n d a

r d r a n g e m

u s t b e u s e d

. T h e C o u

r t d i d say that a l e s s c o s t l y t e c hn o l o g y th a n th e “ b e s t p e r f o r m i n g ” t e c hn o l o g y c o u l d b e u s e d i f i t w o rk s a s l e a s t a s w e l l a s th e l o w e n d o f th e p e r f o r m a n c e r a n g e o f th e “ b e s t p e r f o rm e r . ” The result of the Decision is that SGS will be limited to use of technologies and/or op erational 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 R ule. Subse quent 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 revert ed t o i s s u i n g § 3 1 6 ( b ) r e qu i r e m e n t s o n “ B e s t P r o f e s s i o n a l Ju d g m e n t ” ( B P J ) basis . This was the approach EPA used prior to p r o m u l g a t i o n o f th e P h a s e I I Ru l e . G i v e n C a l i f o rn i a ’ s a dv o c a c y o n 3 1 6 ( b ) i s s u e s , th i s h a s l i t t l e e f f e c t

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 t o t he 316(B) Evaluation o f t he Scattergood Generating Station

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- 4 o n L A D W P ’ s f

a c i l i t i e s . The suspension of the schedule allow s additional time to conduct pilot s tu d i e s t o i d e nt i f

y th e “ b e s t p e r f

o r m i n g ” t e c hn o l o g y f

o r SGS

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

 The technology has pr oven 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 t o t he 316(B) Evaluation o f t he Scattergood Generating Station

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- 5 T ABLE 2 - 1 . P ERTINENT P ROJECT D ATA ( R EVISED T ABLE 2 - 1 FROM THE I NITIAL R EPORT ) Location Los Angeles, California Latitude: N 33 o 5 4 ’ 5 9 ’ ’ Longitu de: W118 o 2 6 ’ 0 8 ’ ’ 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 cf s (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 depth s: (around offshore intake) Maximum: approx 33 ft Minimum: approx 26 ft Normal: approx 30 ft Other info rmation : 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 ftAddendum t o t he 316(B) Evaluation o f t he Scattergood Generating Station

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- 6 Design: 2 halves (2 pumps each f or 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 downstre am 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: spr ay nozzles spray front and back Volume: 1,500 gpm Operati on: once every e ight hour shift Fish return (trough/ pipes): debris trough dis charges 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: vertica l, 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 , 2 00 ft offshore , 400ft away from the intake Depth : 2 7 ft Discharge pipe : 12 ft (inside dia meter) 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: 2 5 % ( 2000
- 2004 ) Unit 1: 25% Unit 2: 31% Unit 4: 23% Average annual energy: 1,815,987 MWh ( net )Addendum t o t he 316(B) Evaluation o f t he Scattergood Generating Station

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- 7 T ABLE 2 - 2 . C OMPARISON OF P ERCENT C OMPOSITION OF E NTRAINED L ARVAE L ENGTHS C OLLECTED 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% Para labrax, 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) E valuation Of The Scattergood Generating Station

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- 8 T ABLE 2 - 3 . I NITIAL S CREENING OF F ISH P ROTECTION A LTERNATIVES AT SGS ( R EVISED T ABLE 3 - 1 FROM THE I NITIAL E VALUATION ) Concept Biological

Effectiveness Proven Engineering

Alternative Available Advantages

O ver Other Concepts Potentia l 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 p reviously 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 T here 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 f or 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 barr ier 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) E valuation Of The Scattergood Generating Station

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- 9 T ABLE 2 - 3 . I NITIAL S CREENING OF F ISH P ROTECTION A LTERNATIVES AT SGS ( R EVISED T ABLE 3 - 1 FROM THE I NITIAL E VALUATION ) Concept Biological

Effectiveness Proven Engineering

Alternative Available Advantages

O ver Other Concepts Potentia l for

Application at SGS Comments Mercury lights no yes yes no Response to mercury light has been shown to be species
- specific; some fi sh 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 h as been suggested, and in some cases ev aluated, 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 e ffectively 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 th ese 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 e ffective 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) E valuation Of The Scattergood Generating Station

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- 10 T ABLE 2 - 3 . I NITIAL S CREENING OF F ISH P ROTECTION A LTERNATIVES AT SGS ( R EVISED T ABLE 3 - 1 FROM THE I NITIAL E VALUATION ) Concept Biological

Effectiveness Proven Engineering

Alternative Available Advantages

O ver Other Concepts Potentia l for

Application at SGS Comments Water jet curtain no yes no no De vices 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 CW ISs. 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 te chnologies 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 V isual cues have been suggested, and in some cases evaluated, as fish protection measures. However, no pr actical 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 N o practical application of these devices has been d eveloped, 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. Fine
mesh 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) E valuation Of The Scattergood Generating Station

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- 11 T ABLE 2 - 3 . I NITIAL S CREENING OF F ISH P ROTECTION A LTERNATIVES AT SGS ( R EVISED T ABLE 3 - 1 FROM THE I NITIAL E VALUATION ) Concept Biological

Effectiveness Proven Engineering

Alternative Available Advantages

O ver Other Concepts Potentia l for

Application at SGS Comments Conventional t raveling 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 B arrier nets can be considered a viable option for protec ting 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 in ch 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 n o 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) E valuation Of The Scattergood Generating Station

2

- 12 T ABLE 2 - 3 . I NITIAL S CREENING OF F ISH P ROTECTION A LTERNATIVES AT SGS ( R EVISED T ABLE 3 - 1 FROM THE I NITIAL E VALUATION ) Concept Biological

Effectiveness Proven Engineering

Alternative Available Advantages

O ver Other Concepts Potentia l for

Application at SGS Comments Cylindrical wedgewire screen intakes yes yes yes yes Wedgewire screens have the pot ential 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 s creens 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 coarse
mesh s creens. 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 transfe r 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) E valuation Of The Scattergood Generating Station

2

- 13 T ABLE 2 - 3 . I NITIAL S CREENING OF F ISH P ROTECTION A LTERNATIVES AT SGS ( R EVISED T ABLE 3 - 1 FROM THE I NITIAL E VALUATION ) Concept Biological

Effectiveness Proven Engineering

Alternative Available Advantages

O ver Other Concepts Potentia l for

Application at SGS Comments Angled screens (fixed or trav eling) 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 invertebrat es 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 r e q u i r e a n e v e n l a r g e r a r e a t h a n “ c o n v e n t i o n a l ” 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 d esigned 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 pote ntial for protecting fish at water intakes. Any consideration of the MIS for CWIS application should be based on future large
scale, 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) E valuation Of The Scattergood Generating Station

2

- 14 T ABLE 2 - 3 . I NITIAL S CREENING OF F ISH P ROTECTION A LTERNATIVES AT SGS ( R EVISED T ABLE 3 - 1 FROM THE I NITIAL E VALUATION ) Concept Biological

Effectiveness Proven Engineering

Alternative Available Advantages

O ver Other Concepts Potentia l 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 e ither 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 spe ed 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 ye s yes yes Closed
- cycle cooling will reduce flow significantly. Depending on the type of closed
cycle 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 t o t he 316(B) Evaluation of t he Scattergood Generating Station

3

- 1 

## 3.0 ENTRAINMENT REDUCTIO N OPTIONS As stated previously, c o m p l i a n c e w i t h E P A ’ s e n t

r a i nm e n t r e d

u c t i o n p e r f

o rm a n c e s t a n d a r d s w i l l b e difficult for marine facilities. Closed

- cycle cooling or dramatic reductions in cool ing water flow by limiting station operations are extreme and costly measures. There are limited technologies that can be cons idered 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 Cal ifornia E nvironmental P rotection A gency . At S GS , 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 effective nes s of any remote cleani ng system may be difficult. The MIS concept is a fish diversion system that guide s 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 imp ingement

. 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 F INE 

### - MESH 

### M ODIFIED 

### T RAVELING 

### S CREENS A l d e n ’ s o r i g i n a l e v a l u a tion 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 w ork 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 e ntrainment 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 cond ucted if LADWP w a n t s t o c o n s i d e r t h i s t e c hn o l o g y f urth e r . T h e p i l o t s tu dy p r o p o s e d f o r L A D W P ’ s H a

r b o r G e n e r at i n g Station (which has lower velocities that SGS) would identify where survival of previously entrained organisms starts to occur. Organisms remov ed 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, whic h emphasizes the need for species and life

- stage

- specific testing to verify survival rates. T he 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 compa rison of two potential fish return cleaning systems is provided in Attachment F.Addendum t o t he 316(B) Evaluation of t he 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 dimensio n 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 W est C oast species of interest at SGS to develop the necessary analy ses. However, adequate data have been developed for E ast C oast species. Based on discussions among Alden and MBC staff, the following surrogates were used for this assessment:

T ABLE 3 - 1. P REDICTED H EAD C APSULE D EPTH (HCD) OF R EPRESENTATIVE

E NTRAINED L AR VAE C OLLECTED 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 mes hes 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

– H ead loss wil l increase from 0.2 to 5 inches in a clean condition, and 2 to 24 inches at 50% blocked with debris.

 Screen rotation speed

– S creens should be designed to operate continuously with a high rotation speed to remove debris quickly. The debris loading will in crease from current conditions due to the smaller opening.

 Screen mesh

– A 0.2 mm screen mesh will require a 1

- inch back up 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

- b a r r a c k o r b a r s c r e e n w i th 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 ma y 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 ma y 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 t o t he 316(B) Evaluation of t he Scattergood Generating Station

3

- 3 Conclusion Fine

- m e s h tr av e l i n g s c r e e n s a r e t e c h n i c a l l y a n “ e x c l u s i o n t e c h n o l o g y . ” H o w e v e r , u n l ike narrow

- slot , wedgewire screens that depend on an air

- burst cleaning system , coupled with ambient currents to
“ c a rr y” i mp i n g e d f

i s h a n d d e b r i s a w a y f

r o m t h e C W I S , t

h i s t e c h n o l o g y u t i l i z e s a “ t r ap a n d tr a n s f e r ” concept. The process of collecting organis ms 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 entrai nment numbers at SGS are such that this technology would probably not meet the entrainment reduction standard. 

### 3.2 N ARROW 

### - SLOT 

### C YLINDRICAL 

### W EDGEWIRE 

### S CREENS LADWP could install narrow

- slot cylindrical wedgewire screen intakes at S GS to reduce fish entrainmen t 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 ad ditional 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 scr eens 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 plat form to house the necessary air

- burst equipmen t. A second option w ould use divers to regularly i nspect 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 re gardless 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 sl ot 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 scr een 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 cy lindrical 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 SG S 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 ). 

### 3.3 M ODULAR 

### I NCLINED 

### S CREENS 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 entrainableAddendum t o t he 316(B) Evaluation of t he Scattergood Generating Station

3

- 4 organisms. Res ults 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 trans port 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 b iofouling 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 fine

me sh 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 sy stems would dictate the technology selection. 

### 3.4 F LOW 

### R EDUCTION 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 seasona l 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 red uctions 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 t wo 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 , s hutting 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 c ould 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 on e pump per unit, loss of pressure in the condenser waterboxes, vibration of the pumps a t 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 t o t he 316(B) Evaluation of t he 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 runn ing at reduced load s or placing a unit(s) on stand by 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 n eed 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 C LOSED 

### - CYCLE 

### C OOLING 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 , i t w o u l d b e c o n s i d e r e d th e “ b e s t p e r f o rm i n g ” t e c hn o l o g y . U n d e r th i s 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 know n at this time. Cooling towers would have the highest overall capital and operating & maintenance ( O&M ) cost of all of the alternatives. 

### 3.6 A DDITIONAL 

### T ECHNOLOGIES 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) a s the source for circulating water. Hyperion abu t s 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 wastewater 4 . This flow is sufficient to provide a ll 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 7 3% 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 us ing 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.htmAddendum t o t he 316(B) Evaluation of t he Scattergood Generating Station

4

- 1 

## 4.0 IMPINGEMENT MORTALIT Y REDUCTION OPTIONS As stated previously, technologies considered for compliance with E P A ’ s e ntr a i nm e nt r e du c t i o n 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 entr ainment 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 develo ped since 2004. 

### 4.1 C OARSE 

### - MESH 

### M ODIFIED 

### T RAVELING 

### S CREENS The velocities approaching the existing traveling water screens are 0. 6 ft /s ec at Units 1 and 2 and 0.7 ft/s ec at Units 3 . These velocities are within the range of velocities that provide good surviva l for most impinged species with traveling screens that have been modified for fish protection (Ristroph s c r e e n s i n A l d e n ’ s o r i g i n a l r e p o r t )

. L i m i t e d s u

r v i v a l d a t a e x i s t f

o r s p e c i e s i m

p i n g e d a t SGS

. Therefore, Alden still recommends conducting pilot stud ies before full

- scale installation. If a pilot

s c a l e s tu dy t o d o c u m e n t i m p i n g e m e n t s u

r v i v a l r a t e s w a s c o n d

u c t e d a t L A D W P ’ s H a r

b o r G e n e r at i n g Station (which has velociti es similar to SGS ), the results would also apply to survival of impinged organisms at S GS

. 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 a nd shellfish sp ecies 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 s urvival rates. Alden believes that methods exist for maintaini ng 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 confou nd 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 trave ling 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 p resent at SGS

. 

### 4.2 W IDE 

### - S LOT 

### C YLINDRICAL 

### W EDGEWIRE SCREENS LADWP could inst all wide

- slot cylindrical wedge wire 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 t otal facility flow. J o h n s o n S c r e e n ’ s Z

- 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 pi pes connected to the existingAddendum t o t he 316(B) Evaluation of t he 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 method s of cleaning the screens would be necessary. One potential method is to build an offshore plat form 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 cylin drical 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

- b urst backwash system has been removed from the total cost of the screens in the updated cost table ( Table 5

- 1 ). 

### 4.3 C OARSE 

### - M ESH 

### B ARRIER 

### N ET 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 d ebris loading and waves could ma ke maintai ning a barrier net highly labor

- intensive and dangerous. Therefore, a barrier is no longer consider ed feasible for SGS. 

### 4.4 M ODULAR 

### I NCLINED 

### S CREENS 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 inclu de 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 elimina tion 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 th e impingement standard could be met with the species present at SGS

. 

### 4.5 F LOW 

### R EDUCTION Prior to the C o u

rt ’ s D e c i s i o n , E P A w a s c o n s i d e r i n g i s s u i n g g u i d a n c e r e l a t i v e t o t h e r e l at i o n s h i p o f impingement and flow. EPA indicated they were considering guidance that would allow facilities to assume proportionality between flow and impingement. SGS has complet ed its year of impingementAddendum t o t he 316(B) Evaluation of t he 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 con sidered 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 C LOSED 

### - CYCLE COOLING Closed

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

- cycle cooling ret rofit 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 conside r it for impingement only. 

### 4.7 A DDITIONAL 

### T ECHNOLOGIES There are no additional technologies that would be suitable for reducing impingement at SGS

.Addendum t o t he 316(B) Evaluation of t he 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 200 2 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 t o t he 316(B) Evaluation o f t he Scattergood Generating Station

Draft 5

- 2 T ABLE 5 - 1 . A LDEN ’ S A PPRAISAL L EVEL C OSTS OF E VALUATED A LTERNATIVES Estimated from Alden Database

Alternative Construction Costs (200 6 $) Replacement

Power During Shutdown (MWh) Total

Capital Cost (200 6 $) 1 O&M

Costs (200 6 $) Lost

Generation (MWh) 2 Annualized

Capital Costs (200 6 $) 3 Incremental

Annualized O&M Costs (200 6 $) 1, 2 Total

Incremental Annualized Costs (200 6 $) 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 wedg ewire 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 wedgew ire 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 closed
cycle cooling system 4 $115,584,000 910,000 $161,084,000 $1,546,000 39,734 $20,123,000 $3,454,000 $23,577,000 1. Based o n 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)

.Adde ndum t o t he 316(B) Evaluation o f t he Scattergood Generating Station

6

- 1 

## 6.0 DATA GAPS AND UNCERT AINTIES 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 th e site. Table 6

- 1 p rovides 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 H aynes G enerating S tation (MIS) will provide data on length

related, species

- specific survival. The results of both studies would also provide survival data that apply to imp ingement (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 collecte d 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, ho wever, 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 re duced by pilot studies. It is anticipated th at s urv i v a l am o n g “ h e a rt y ” a n d “ f r a g i l e ’ s p e c i e s will vary and a change in composition towards
“ f r a g i l e ” s p e c i e s w i l l j e o p a r d i z e c o m p l i a n c e p o t e n t i a l

.Adde ndum t o t he 316(B) Evaluation o f t he Scattergood Generating Station

6

- 2 T ABLE 6 - 1. D ATA G APS AND U NCERTAINTIES FOR A LTERNATIVES Al ternative 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

 Annu al variability in species composition. Narrow

- slot Wedgewire Screens  Length and species

- specific exclusion data; and

 Biofouling impacts.  Effective mesh size;

 E f f e c t i v e “ s w e e p i n g ” v e l o c i t y ;
 Effective cleaning method ; and

 Annual variability in species co mposition. 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

 A nnual 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.  E f f e c t i v e “ s w e e p i n g ” v e l o c i t y ;
 Effective cleaning method ; and

 Annual variability in species composition. Coarse Mesh Barrier Net  Macro fouling rate; and

 Biofouling impacts. Ability to mainta in the net in an offshore environment.
Use of R eclaimed W ater 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 o f Hyperion discharge pipe; and

 E xisting infr astructure 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 retrofi t.Adde ndum t o t he 316(B) Evaluation o f t he Scattergood Generating Station

7

- 1 

## 7.0 C ONCLUSIONS 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 f u n c t i o n o n th e “ tr ap a n d tr a n s f e r ” c o n c e p t a n d r e q

u i r e th e s a m e t y

p e o f f i s h a n d d e b r i s returns as Ristroph screens. The potential use of either of thes e technologies does not change A l d e n ’ s p r e v i o u s a s s e s s m e nt
.  T h e 2 0 0 6 i m

p i n g e m e nt a

n d e n tr a i n m e nt d at a d o n o t a l t e r A l d e n ’ s s e l e c t i o n o f ap p r o p r i at e technologies for consideration in reducing entrainment at SGS

. The overall efficacy of any entrainment redu ction technology is mitigated by the predominance of very early life history stages.

 The Court ’ s d ecision to remand restoration and the cost

- b e n e f i t t e s t s e v e r e l y l i m i t L A D W P ’ s o p t i o n s , b u t d o n o t a f

f e c t A l d e n ’ s t e c h

n o l o g y a n d o p e r a t i o n a l m e a s u r e s a s s e s s m e nts.

 B a s e d o n E P A ’ s p o s i t i o n , i t i s a n t i c i p at e d t h at a s c h e du l e e x t e n s i o n w i l l b e p r o v i d e d t o 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

- m e s h tr a v e l i n g s c r e e n s a r e t e c h n i c a l l y a

n “ e x c l u s i o n t e c hn ology

. ” However, unlike narrow - slot, wedgewire screens that depend on an air

- burst cleaning system , coupled w i th a m b i e nt c u rr e nt s t o “ c a r

r y” i m p i n g e d f i s h a n d d e b r i s a w a y f

r o m t h e C W I S , th i s t e c h n o l o g y ut i l i z e s a “ tr a p a n d tr a n s f

e r ” c o n c e p t
. T h e p r o c e s s of 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 narrow slot, wedgewire screens

.  As with the fine

- m esh 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 optio ns.
 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 t wo 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 w here placing a unit(s) on stand by would result i n some flow reduction credit. Use of VSDs could be considered to better control flowAdde ndum t o t he 316(B) Evaluation o f t he 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 t o d e t e r m i n e th e “ b e s t p e r f o rm i n g ” e n t

r a i nm e nt r e du c t i o n t e c h n o l o g y .  Using r eclaimed water from Hyperion could significantly reduce the circulating water withdrawal from the ocean. If only Unit 3 used reclaimed water , then a 55% reduction ca n 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 entrain ment 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 ’ s Decision.

 Based on E P A ’ s p o s i t i o n , it is anticipated that a s chedule 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 “ E v a l u a t i o n o f t h e Scattergood Generating Stations with r e s p e c t t o t h e E n v i r o nm e nt a l P r o t e c t i o n A g e n c y ’ s 3 1 6 ( b ) R u l e s f o r E x i s t i n g F a c i l i t i e s ” , D e c e m b e r 2004, prepared by Alde n 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 S GS , including potential cost

effective 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 f ish protection technologies to meet the applicable performance standards for S GS and discussion of approximate costs for the feasible alternatives. As part of this alternatives analysis, Alden reviewed operational options for meeting the applicable perfor mance standards. This report addressed technologies, operational changes, and restoration measures that LADWP could implement to meet the Rule. T h e U

. S

. E n v i r o n m e n t a l P r o t e c t i o n A g e n c y ’ s ( E P A ’ s ) favored approach was to reduce total fish losses, which di d 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 suc h 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 cons idered by LADWP to meet the Impingement Mortality and Entrainment ( IM&E ) standards at SGS was presented in th e report. A l d e n ’ s p r e l i m i n a

r y j u d g m e n t o n h o w l i k e l y th e s e a l t e rn at i v e s we re to actually meet these sta ndards was summarized as follows :

Alternat ive Will It Meet t he Impingement Mortality Reduction Standard? Will It Meet t he Entrainment Reduction Standard?

Expanded intake with fine
- mesh Ristroph screens A l though impingement mortality is highly variable , d ata show that Ristroph screens incorporatin g 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 a s s u r e t h e s c r e e n s ’ p e r f o r m a n c e
. Yes

Retrofit intake with 0.5 mm wedgewire scr eens Yes YesAttachment A Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

2 Alternat ive Will It Meet t he Impingement Mortality Reduction Standard? Will It Meet t he Entrainment Reduction Standard?

Install coarse
- mesh Ristroph screens in existing intake Perhaps, al though impingement mortality is highly variable. Data show that Ristroph screens incorporating the latest bucket designs typically achieve higher survival rates than older Ri stroph screens. LADWP should consider pilot
- scale studies prior to full
- scale i n s t a l l a t i o n t o a s s u r e t h e s c r e e n s ’ performance. No

Retrofit intake with 9.5 mm wedgewire screens Yes No Coarse
- mesh barrier net Yes

– provided that the barrier can be mainta ined 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 6 0% 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 A l d e n ’ s A n n u a l i z e d C o s t s (2002 $) E P A ’ s A n n u a l i z e d C o s t s (2002 $) Expanded intake with fine
- mesh Ristroph screens $4,777,000 Retrofit intake with 0.5mm wedgewire screens $4,1 91,000 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 $53,72 3,000 Retrofit plant with closed
- cycle cooling system $42,663,000 $0Attachment 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 morta lity 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 coa rse - 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 entrainme nt 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

- mes h 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 d e t e rm i n e w

h a t c o n s t i tut e s “ s i g n i f i c a nt l y g r e a t e r th a n . ” P r e s u m ab l y , C a l ifornia E nvironmental P rotection A gency 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 a re 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 de signs 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 impingeable 5 fish by 80

– 9 5 % f r o m t h e “ c a l c u l a t i o n b a s e l i n e . ”

 Alternatives should be designed to reduce entrainment by 60

– 9 0 % f r o m th e “ 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 curr ent 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 thro ugh a 3/8 in. mesh. By extension, any organism t h at i s t o o l a

r g e t o b e e nt r a i n e d t

h r o u g h a 3 / 8 i n . m e s h w o u l d b e c o n s i d e r e d “ i m p i n g e ab l e . ”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.

 Alternat ives 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 adver sely 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 (preferabl y from full

- s c a l e ap p l i c at i o n ) w e r e a v a i l ab l e th at d o c u m e nt e d a t e c h n o l o g y ’ s e f f e c t i v e n e s s w i th o n e o r m o r e 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 bee n 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 h as been proven effective at reducing losses for many species an d 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 fu lly developed and/or tested for biological effectiveness. These t e c h n o l o g i e s i n c l u d e B e au d r e y ’ s F i s h P r o t e c t i o n S o l u t i o n (FPS TM ), Filtrex filter system , fine

- mesh flat

- panel screens with D ebris and O rganism C ollection (DOC) system , a n d G e i g e r ’ s M u l t i D i s c TM Screening System

.

 B e a u dr e y ’ s F P S TM system consists of a fine

- mesh fixed screen with a fish collection sc ope positioned below the water ’ s surface. The collection scope travels along the screen face , collecting fish and debris , with suction provided by a fish pump.

 F i l t r e x f

i l t e r s y s t e m c o n s i s t s o f f

i l t e r “ c a n d l e s ” ap p r o x i m a t e l y 5 i n c h e s l o n g m a d e o f p l a s t i c wafers stacked and fastened together with a central spring. Groves between stacked wafers provide filtration from 5 to 40 microns , and the flow c apacity 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 allowe d to separate by compressi on 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 s ystem consists of flat panel 0.5 mm screens, a debris and organi sm 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 ’ s surface and would remove debris andAttachment A Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

5 impinged fish from the screens. S ubmerged fish pu mps would create s uction 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.

 T h e G e i g e r M u l t i D i s c TM S c r e e n i n g S y s t e m c o n s i s t s o f a s i n g l e - pass, front

- wash, vertical s c r e e n w i th f

i s h h a n d l i n g c ap ab i l i t i e s . T h i s d e s i g n r e s u l t s i n a “ z e r o c a rr yo v e r ” f i s h/ d e b r i s 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 fu lly 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 substan tially 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 st rong 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 locat ion. 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. High

frequency (120 kHz) sound has been shown to effectively and repeatedly repel members of the genus Alosa (American shad, alewife and bl ueback 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 S GS , 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 fr om further consideration at S GS

. 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 i mpinged 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 mor t ality 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 clea ning 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 S GS

. 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 phys ical 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 barri er, 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 conventio nal traveling screens because of the lower design velocity. Rotary drum screens are t ypically installed in channels where water elevations are relatively constant and water depths are less than 12 ft, which is not the case at S GS . 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 technolog ies 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 div ert 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 , ha s 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 S GS

. Cylindrical wedgewire screens have an eng ineering 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 (Co mpliance 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 prov ide 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 , we dgewire screens in the preliminary evaluation for S GS

.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 Addendu m)

. 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 tech nology 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 e ntrainment 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, alth ough they may also hinder navigation and recreation at SGS

. The Team has included a coarse mesh barrier net in the preliminary evaluation as a potential low cost option to reduce impingement at the S GS CWIS. The preliminary screening of intake technologie s 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 S GS :

 Installation of fine

- mesh [i.e., 0.5 mm (0.02 in.) square woven mesh] Ristroph screens wi th 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

 Install ation of a MIS in the intake

. T wo flow reduction options to reduce fish impingement and entrainment at S GS ’ i n t a k e structure have been identified . These options are:

 Reduced circulating water pump oper ation ; and

 Install ing 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 perio ds of peak abundance of entrainable organisms. To maintain the plant discharge within the permitted thermal limits, reduced pump flow may require a reduc tion in plant output. Flow limitation could be achieved by shutting down pumps, throttling discharge p umps, 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 so lution 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 c ooling could greatly reduce both IM&E at S GS . 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 mechani cal 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 aes thetic and air quality impacts th an 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 th ese 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 OP TIONS 1.0 INTRODUCTION In 2004, Alden Research Laboratory , Inc. (Alden) and the Electric Power Resea rch Institute (EPRI) c o n du c t e d a 3 1 6 ( b ) s tr a

t e g i c a s s e s s m e nt f

o r th e L o s A n g e l e s D e p a r tm e nt o f W a t e r a n d P o w e r ’ s (LADWP) Generating Stations : Harbor Generating Station (HGS), Haynes Generating Station (HnGS), and Scattergood Generating Station (SGS). As pa rt 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 ALDE N/EPRI RESTORATION E VALUATION 2.1 T YPES OF R ESTORATION A PPLICABLE 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 restora tion 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 who le 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 implement ation of technologies, operational measures, and/or alternative site

- specific requirements. 

### 2.2 S PECIFIC R ESTORATION E XAMPLES FOR HGS, H N GS, AND SGS A l d e n/E P R I p r o v i d e d s e v e r a l e x amp l e s o f p o t e nt i a l r e s t o r at i o n p r o j e c t s ap p l i c ab l e t o L A D W P ’ s coastal generating stations. These examples are summarized below.Attachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

2 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), A merican 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 P r o gr am , t h e U

. S

. F i s h a

n d W i l d l i f

e S e rv i c e P a

rtn e r s h i p f

o r F i s h a n d W i l d l i f

e , a n d C o a s t a l A m e r i c a ’ s Corporate Wetlands Restorati on 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 rest oration projects could include runoff abatement programs and removal of contaminated sediments to improve water/sediment quality and habitat. 

### 2.3 316( B ) R ESTORATION I MPLEMENTATION P ROCESS The use of restoration as a compliance alternative will require coordina tion 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 restorati on 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 , andAttachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

3  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 pro gress 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 impleme ntation 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 a ttached). 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 accomp lish 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 SPECIFI C RESTORATION PROJEC TS 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 w ould have a similar e ffect on productivity. Other projects that involve watershed management could reduce wetlandAttachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

4 sedimentation and thus preserve existing wetland habitat. Projects that enhance the biological productivity of Santa Monica and San Pedro ba ys 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. T h e “ v a l u e ” o f th e e c o l o g i c a l s e r v i c e s o r b e n e f i t s th at w i l l r e s u l t f

r o m i m p l e m e n t a t i o n o f a n y o f th e s e restoration pr ojects will be assessed using various habitat models to demonstrate that the ecological
“ c r e d i t s ” g a i n e d t h r o u g h r e s t o r at i o n w i l l o u tw e i g h t h e e c o l o g i c a l “ d e b i t s ” c a u s e d b y th e I M & E losses. Using local environmental planning documents and resource agency r ecovery 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 equivalen t 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 I M &E. Restoration projects are presented that offset potentia l population effects of IM&E on specific species and at the same time contribute to the overall health of nearshore/coastal habitats. 

### 3.1 C OASTAL W ETLAND P ROJECTS At one time , coastal lagoons, salt marshes, and other wetlands created by the merging of creeks a nd 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 wer e 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 spaw ning 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 p r o j e c t ’ s q u a l i t at i v e a n d qu a

n t i t a t i v e b e n e f

i t s r e l a t i v e t o b a s e l i n e I M & E l o s s e s . P r o j e c t s considered 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, freshwate r 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 buil ding 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 nativeAttachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

5 plants , and the re

- c r e a ti o n o f a n a d d i t i o n a l 2 1⁄2 a c r e s o f f r e s h w a t e r w e t l an d

/ du n e / r i p a ri a n h a

b i t a t
. 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 associate d 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 se asonal 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 High way). 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 sp ecies 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 Ball ona 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 developmen t , 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 or ganizations 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 t o L A D W P ’ s H n G S

. T he 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 Alamit os 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 makeAttachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

6 it less than ideal. The recently submitted final report of the City of Long Bea ch, 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, a n d th e a r e a ’ s h i s t o r y o f u s e a s a h a z a r d o u s w a s t e d i s p o sal 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 th e 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 Wetl ands 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 developme nt 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 imp rovement 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 o ffset 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 i n and around the bay from the Irvine Company and the transfer of 214 acres of tidal wetlands from the County of Orange to the s tate. 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 ti dal 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 C OASTAL W ATERSHED P R OJECTS 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 isAttachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

7 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 tr ibutary 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 P ROJECTS TO E RADICATE N ON - N ATIVE P LANTS F ROM W ETLANDS A number of projects hav e 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 sedim entation, 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, an d Solstice Creek (a tributary of Malibu Creek). 

### 3.4 N EARSHORE C OASTAL P ROJECTS 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 c onstruction 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 intert idal 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 a s 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 year s , 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. Increas ing 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 performanceAttachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

8 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 fo r 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 Progr am, could potentially be used to restock species, although the 316(b) regulations discourage a hatchery replacement approach. 

### 3.5 P RELIMINARY R ANKING /E VALUATION OF R ESTORATION P ROJECTS A set of selection criteria was developed for ranking the prospective habit at 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 pr oject  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 match ing 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 weig hing 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 ad jacent 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 projec t 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 f eed into the affected areas can have a high ranking , but are not ideal.Attachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

9 N e x u s t o f

a c i l i ty ’ s I M & E e f

f e c t s 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 t he 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 us ed 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 citizen ry? 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 bene fit 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 s hort

- term, transient, benefits. This category works in conjunction with the two previous categories. Success of comparable restoration projects T h i s c at e g o r y i s s i m i l a r t o th e “ T e c hn i c a l F e a s i b i l i t y” c a t e g o r y , b u t g o e s a s t e p b e yo n d f e a s i b i l i t y t o the ques tion 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).Attachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

10 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 conflict s, which mesh well with ongoing projects and policy, will receive the highest rankings. Projects that are inconsistent with current environment policy and ongoing p r o j e c t s w i l l r e c e i v e a l o w e r r a n k i n g ( s e e a l s o “ B a s i c n e e d o r j u s t i f i c at i o n f o r p r o j e c t ” a n d “ L e g a l hur d l e s ” )

. 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 suc h requirements. The cost of overcoming these hurdles (time and money) should also be i n c o r p o r a t e d i nt o th e e v a l u a t i o n o f t h e p r o j e c t i n o th e r c a t e g o r i e s ( “ I m p l e m e nt a t i o n c o s t , ” “ T i m e before benefits accrue , ” a n d “ B a s i c n e e d o r j u s t i f i c at i o n f o r p r o j e c t ” )

. 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 I M&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 ( “ C o s t / B e n e f

i t ” )

. Funding opportunities (matching funds, levera ging 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 categ o r i e s l i k e “ B a s i c n e e d o r j u s t i f i c a t i o n f o r t h e p r o j e c t , ” “ S t a k e h o l d e r support , ” a

n d e v e n “ L e g a l h ur d l e s . ” N e w e r , m o r e i n n o v a t i v e , p r o j e c t s m a y h a v e f

e w e r f un d i n g opportunities and would rank lower. Ability to measure performance Can the beneficial enviro nmental 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 proje cts 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 ca n 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 inverteb rates, 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

- fo r - 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 w e t l a n d ( s e e “ A b i l i t y t o m e a s u r e p e r f o rm a n c e ” ) ? R a n k i n g i n th i s c a t e gory may be somewhat subjective with both the cost and benefits of a project placed somewhere along a gradient that ranges from small to large.Attachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

11 Administrative considerations How large are the administrative needs of a potential project. This includes takin g 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 ran kings 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. A n a d d i t i o n a l a s p e c t n o t c o n s i d e r e d i n th e c r i t e r i o n o f ‘ O p p o r tun ities for leveraging of f un d s / A v a i l a b i l i t y o f m a t c h i n g f

un d s ’ i s t h e p o t e nt i a l f

o r r e s t o r at i o n c o s t s t o b e s h a r e d am o n g th e power generating facilities located on the coast in Santa Monica Bay or in the larger Los Angeles Basin coastal area. This would in crease 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. T he 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 im mediately 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 on e 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 T ABLE B - 1. Q UALITATIVE R ANKING , WITH 1 B EING L OWEST AND 5 B EING H IGHEST OF P OTENTIAL R ESTORATION P ROJEC TS FOR O FFSETTING S CATTERGOOD G ENERATING S TATION IM&E L OSSES .

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 57Attachment B Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

Draft 13 

## 4.0 CONCLUSIONS AND RECO MMENDATIONS 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 Wetlan ds 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 proce eding 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 w e t l a n d s , a n d t

h e a r e a ’ s h i s t o r y o f u s e a s a h a z a r d o u s w a s t e di s p o s a l s i t e . T h e s e c o n c e rn s 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 bed s 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.) o n 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 pro ject has shown that communities develop fairly rapidly on the new habitat.Attachment C Addendum To The 316(B) Eval uation Of The Scattergood Generating Station

Draft 1 

## ATTACHMENT C - V ELOCITY 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: 76 6.5 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 ft 2 

### Number of Intake Pipes: 1 Screen Width: 6.0 ft Number of Bays: Units 1 &2: 2 per unit Unit 3: 4 Screenhous e Invert: El.

- 23.5 ft

Formula Used


### )

( ) ( ) ( area

A flow Q velocity V 
Calculations

sec / 5

. 1 * 5

. 32 * 5 5

. 766 ) ( ft ft ft cfs p Velocityca V 

 



### sec

/ 8

. 6 0

. 113 5

. 766 ) ( 2 

### ft

ft cfs s Intakepipe V 



sec / 6

. 0 ) 5

. 23 0

. 0 ( * 6 * 2 8

. 173 ) 2 & 1 ( ft ft ft ft cfs screens Units V   



### sec / 7

. 0 ) 5

. 23 0

. 0 ( * 6 * 4 8

. 418 ) 3 ( ft ft ft ft cfs screens Unit V   Attachment D Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

1 

## ATTACHMENT D - F ISH MORPHOMETRY AND SCREEN MESH HEADLOSS The following inform ation on fish morphometry was developed by LMS as part of a NJPDES Permit s p e c i a l c o n d i t i o n f

o r P S E G S e rv i c e s C o r

p o r at i o n ’ s S a l e m G e n e r at i n g S t a t i o n 6

. This study was designed to use physical measurements from preserved ichthyoplankton to compute the expe cted size of larval fish retained by plankton nets of various mesh size s . “

... 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 grea test 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 t his 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 fo r 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 0.0 53413 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 1Attachment 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 1Attachment 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 0.75 505931 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 0.000 13543 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 1Attachment 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
- 0.02 314 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 1Attachment 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 2.50 64E
- 21 1Attachment 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 Scr een characteristics:

Screen Mesh Wire

spacing (in) Wire

dia. (in) Wire

dia. (mm) opening

(mm) Open

area Back up screen (1" mesh) combined

open area w ith 1" back up 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% 1 8 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. B ongo 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 plankto n 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 meshe s. In D.J. Tranter (ed.), Part I, Review on zooplankton sampling methods, p. 77

- 86. UNESCO Monograph. Oceanography. Methodology. 2, Zooplankton SamplingAttachment E Addendum To The 316(B) Evaluation Of The Scattergood Generating Station

1 

## ATTACHMENT E - P OTENTIAL FISH RETURN CLEANING SYSTEMS Fish and debris removed from fine

- mesh travelin g 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 w as 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 cons tructed 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 transpor t 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 Operati on 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 retur n 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 Cost 1 $213,000 $279,000 O&M Costs 1 $18,000 $19,000 1. Costs are in 2006 and are based on the same assumptio ns 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 ap p l i c ab l e t o t h e f

i s h r e t u rn r e q u i r e d f o r M o d u l a r In c l u d e d S c r e e n s . T h e f i s h r e t u r n p i p e f o r th e M I S ’ 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 op tions would be very similar but higher than those in the table.Attac hment E Addendum To The 316(B) Evaluation Of The Scattergood Gener ating Station

2 Estimated from Alden Database

Alternative Construction Costs (200 6 $) Replacement Power

During Shutdown (MWh) Total Capital

Cost (200 6 $) 1 O&M

Costs (200 6 $) Lost

Generation (MWh) 2 A nnualized

Capital Costs (200 6 $) 3 Incremental

Annualized O&M Costs (200 6 $) 1, 2 Total

Incremental Annualized Costs (200 6 $) 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 eithe r 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 $169,000Attachment F Addendum To The 316(B) Evaluation Of The Scattergood Gener ating Station

1 

## ATTACHMENT F - USE OF RECLAIMED WAT ER 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 weath er 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 Hyperi on, 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 requir ed. 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 S GS is not known.

 The existing once

- through sys tem 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 Hyperio n outfall my need to be shut down during the final connection to SGS, to prevent spill age 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 whe n SGS is not operating.
 Discharge

 The S GS 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 Gener ating Station

2  If reclaime d 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

- cy cle 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 S GS. Three potential options using reclaimed water were looked at. The first opt ion 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 ac tual 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 S GS to be returned to th e Hyperion outfall pipe. These costs use the same methodology as the costs calculated in the 2004 report.