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



# A DDENDUM 

# T O 

# E VALUATION OF THE 

# H ARBOR 

# 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
Prepared by 

### Alden Research Laborat ory, 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 To The 316(B) Evaluation Of The H arbor Generating Station

i 

## 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 I MPINGEMENT M ORTALITY AND E NTRAINMENT C HARACTERIZATION
................... 2

- 2 2.3 C OSTS
................................ ................................ ................................ ................... 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
- MES H M ODIFIED T RAVELING S CREENS
................................ .......................... 3

- 1 3.2 R ETROFIT I NTAKE WITH 0.5 MM W EDGEWIRE S CREENS
................................ ......... 3

- 3 3.3 F LOW R EDUCTION
................................ ................................ ................................ . 3

- 3 3.4 C LOSED
- CYCLE C OOLING
................................ ................................ ...................... 3

- 4 3.5 A DDITIONAL T ECHNOLOGIES
................................ ................................ ................. 3

- 4 

## 4.0 Impingement Morta lity Reduction Options ................................ ..... 4 - 1 4.1 C OARSE
- MESH M ODIFIED T RAVELING S CREENS
................................ .................... 4

- 1 4.2 W IDE
- SLOT C YLINDRICAL W EDGEWIRE S CREENS
................................ .................. 4

- 1 4.3 F LOW R EDUCTION
................................ ................................ ................................ . 4

- 2 4.4 C LOSED
- C YCLE C OOLING
................................ ................................ ...................... 4

- 2 4.5 A DDITIONAL I MP INGEMENT R EDUCING T ECHNOLOGIES
................................ ........ 4

- 2 

## 5.0 Cost Update ................................ ................................ ........................ 5 - 1 6.0 Data Gaps and Uncertainties ................................ ............................ 6 - 1 7.0 Conclusions ................................ ................................ ........................ 7 - 1
L IST OF 

### T ABLES TABLE 2

- 1. PERTINENT PROJEC T DATA (REVISED TABL E 2

- 1 FROM THE INITIAL REPORT)

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

- 5 TABLE 2

- 2. REVISED TABLE 2

- 3 FROM THE INITIAL E VALUATION

– COMPARISON OF PERCEN T COMPOSITION OF ENT RAINED LARVAE LENGTHS COLLECTED AT HGS

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

- 7 TABLE 2

- 3. INITIAL SCREENIN G OF FISH PROTECTION ALTERNATIVES AT HGS (REVISED TABLE 3

- 1 FROM THE INITIAL E VALUATION)

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

- 8 TABLE 3

- 1. PREDICTED HEAD C APSULE DEPTH (HCD) F OR LARVAE C OLLECTED AT HGS

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

- 1 TABLE 5

- 1

. A L D E N ’ S A P P R A I S A L LEVEL COSTS OF EVA LUATED ALTERNATIVES

...... 5

- 2 TABLE 6

- 1. ALTERNATIVE DATA GAPS A ND UNCERTAINTIES

................................ ........ 6

- 1 TABLE B

- 1. QUALITATIVE RANK ING, WITH 1 BEING LO WEST AND 5 BEING HIGHEST, OF POTENTIA L RESTORATION PROJEC TS FOR OFFSETTING HARBOR GENERATING ST ATION IM&E LOSSES.

................................ ........................... 12Addendum To The 316(B) Evaluation Of The H arbor Generating Station

ii 

### L IST OF 

### A TTACHMENTS ATTACHMENT A

- SUMMARY OF 2004 EVA LUATION OF HGS ATTACHMENT B

- LADWP RESTORATION O PTIONS ATTACHMENT C

- VELOCITY CALCULATIO NS ATTACHMENT D

- FISH MORPHOMETRY AN D SCREEN MESH HEADLO SS ATTACHMENT E

- POTENTIAL FISH RETU RN CLEANING SYSTEMSAddendum To The 316(B) Evaluation Of The H arbor Generating Station

iii 

### 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 f

eet 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 Modula r Inclined Screens mm millimeter MW megawatts MWh megawatt hour NOAA National Oceanic and Atmospheric Administration O&M Operating and Maintenance VSD Variable Speed DrivesAddendum To The 316(B) Evaluation Of The H arbor Generating Station

1 - 1 

## 1.0 INTRODUCTION In December 2004, Alden Research Laboratory, Inc. (Alden) , unde r contract to the Electric Power Research Institute (EPRI) , d e v e l o p e d a r e p o rt e n t i t l e d “ E v a l u at i o n o f th e H a rb o r G e n e r a t i n g S t at i o n w i th r e s p e c t t o t h e E n v i r o n m 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 ” f

o r t h e Los Angeles Department of Water and Power (LADWP). This report provided an assessment of the universe of technologies available for consideration for fish protection at steam generating stations and resulted in a limited number of technologies and operational measures that were considered appropriate for the Harbor Generating Station (HGS). A summary of the results of the 2004 evaluation is provided in Attachment A. HGS is subject to both the impingement mortality and entrainment (IM&E) reduction performance standards. However , o nly technologies that would reduce both IM&E were evaluated for this addendum . Technologies that would only reduce impingement were not evaluated as the layout of the HGS Cooling Water Intake System ( CWIS ) is such that the cost of impingement mortality only technologies would be similar to IM&E technologies. The technologies evaluated in the initial detailed 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 reduct ion standard. Two technologies ( i.e. fine

- mesh Ristroph traveling screens and cylindrical wedgewire screens) were considered as entrainment and entrainment/impingement reducing options at HGS. As discussed below, more current information allows for re

- c onsideration of the previously evaluated technologies and operational measures, and the consideration of technologies whose status has changed since the 2004 report. This report will serve as an addendum to the 2004 report. An update to the restoration e valuation is provided in Attachment B. To develop this addendum , Alden consulted with EPRI, MBC Applied Environmental (MBC), Tenera Environmental, Inc. (Tenera) and URS Corporation (URS).Addendum To The 316(B) Evaluation Of The H arbor Generating Station

2 - 1 

## 2.0 ADDITIONAL INFORMATI ON CURRENTLY AVAILAB LE The following new info 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 technologies have become available;

 LADWP has completed a one

- year IM&E study;

 Costs can be updated to 2006 values; and

 The Second Circuit Court (Court) issued a decision (D ecision) 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 discuss ion of the impacts of these new data on the alternatives previously evaluated and additional alternatives that are available for H GS is presented in the following sections. 

### 2.1 A DDITIONAL 

### T ECHNOLOGIES In the 2004 report, there were four technologies characteri 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 o n S y s t e m ( F P S ) ;
 Filtrex Filter Candles;

 Debris and Organism Collector (DOC); 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 testing. The original FPS has also not been tested. However, a variation of the original system , w

h i c h u t i l i z e s c i r c u l a r r o t a t i n g s c r e e n s w i t h 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 at one facility and is current ly being tested. Therefore, there is no new information to assess the feasibility, cost, or effectiveness of these three technologies at this time. The multi

- disc screens with fish protection features (for impingement) have been installed at two faciliti es. The first installation was at the Potomac Generating 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 result s from Ristroph screens. In addition, this technology provides the benefit of eliminating carryover. The second installation was in late 2006 at the Salem Generating Station on the Delaware River and no data are available at this time. Another emerging technology with fish protection features, not available in 2004, is a plastic belt screen manufactured by Hydrolox. These screens are lighter and potentially less costly to install and operate than other traveling screens. The plastic belt screens are n ew and do not have any long

- term operational data, but pilot studies currently planned at one estuarine site on Long Island, NY should provide useful information on biological efficacy and operational issues. Because of the material used and way that the screen is constructed, the smallest mesh size available is 1.75 millimeters ( mm ) a t th i s t i m e . T h

u s , th i s t e c h n o l o g y h a s t h e s am e “ l i m i t a t i o n ” a s th e M o d u l a r I n c l i n e d S c r e e n s y s t e m (MIS) in excluding only larger entrained organisms and , t herefore , would n ot meet entrainment performance standards for HGS.Addendum To The 316(B) Evaluation Of The H arbor Generating Station

2 - 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 u n c t i o n o n th e “ tr a

p a n d tr a n s f e r ” concept and require the same type of fish and debris 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 det ermine the survival of entrainable

sized organisms impinged on fine

- mesh traveling screens. The testing is being conducted in the recently refurbished large, fish testing facility at Alden. Modifications to this facility were made to allow for installa tion of three test screens the Geiger Multi

- Disc Screen (0.5 mm), a Brackett

- Green through

- flow screen (0.5 mm), and a Hydrolox screen (1.0 mm). Parameters to be evaluated include :
 Two approach velocities (0.5 and 1.0 ft/sec)

 Two durations of impingement (4 and 8 minutes)

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

 Three length classes

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

### 2.2 I MPINGEMENT 

### M ORTALITY AND 

### E NTRAINMENT 

### C HARACTERIZATION T he relative contribution of the most abundant species impinged has varied greatly from 1978/1979 to 2006 . P rominent species impinged in 2006 , but not in 1978/1979 , include round stingray, black perch, barred sand bass, giant kelpfish, spotted kelpfish, and white seaperch . Th ese impingement data d o n o t c h a n g e 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 h nologies for consideration at H GS. As expected, the entrainment data showed similar results. Gobies, blennies, silversides, white cr oaker, and northern anchovy are abundant species entrained. Of most interest were the results of the entrainment life history characterization. The 2006 results confirmed the 1978/1979 results and documented that 9 7

- 100% (depending on species) of entrain e d o r g a n i s m s w e r e “p r e - t r a n s f

o rm at i o n ” stage. That is, the vast majority of entrained fish were less than 1 2 mm in length. The lengths of larvae collected in 2006 are provided in Table 2

- 2. This t able replaces Table 2

- 8 in the initial evaluation. These 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 on in reducing entrainment at H GS. As discussed in Section 3, the overall efficacy of any entrainment reduction technology is mitigated by the predominance of such early lif e history stages. 

### 2.3 C OSTS Alden has revised and included in Section 5 of this A ddendum Table 5

- 1 (i.e., Table 6

- 3 from 2004 report) to reflect current (2006) costs of appropriate technologies. 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

1 Based on consumer price index from 2002 through 2006.Addendum To The 316(B) Evaluation Of The H arbor Generating Station

2 - 3 to $50/MWh 2

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

- 1 have been modified to reflect the updated evaluations. 

### 2.4 S ECOND 

### C IRCUIT 

### C OURT 

### D EC ISION The Court issued its Decision on the Phase II Rule on January 27, 2007. This Decision had significant impacts on the compliance alternatives and options discussed in the 2004 Report. The major components of the Decision are:

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

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

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

 The Court also remanded to EPA the Cost

- Cost Test and Technology Installation and O p e r at i o n P l a n 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 C ourt 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 retr ofit with these technologies. The two other factors EPA may consider are adverse environmental impacts associated with closed

- cycle cooling and impacts to energy production and efficiency. A second major component of the Decision is a requirement to us 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 . T h e C o u rt d e t e rm i n e d th at i f E P A c h o s e 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

- e f f e c t i v e . R at h e r , 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 ropriate performance standard range must be used. The Court did s a y th a t 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 H GS will be limited to use of technologies and/or operational measures for compliance. Use of the Cost

- Cost Test may be available if it is proposed for public review and comment. However, there is some risk that EPA could alter Ap pendix A costs and/or implementation provisions in the revised Rule. Subsequent to the Decision , EPA has suspended the Rule. EPA did not budget for a major 316(b) rulemaking in 2007, so it is not clear when a revised Phase II Rule would become effective. The r e s u l t i s u n c e rt a i n t y a s t o w h e n c o mp l i a n c e w i l l b e r e q u i r e d

. E P A h a s r e v e rt e d 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 Judgment ” ( B P J ) b a s i s . T h i s w a s th e ap p r o a c h E P A u s e d p r i o r t o promulgation of the Phase II Rule. Given California ’ s a d v 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 o n L A D W P ’ s f

a c i l i t i e s . T h e s u s p e n s i o n o f th e s c h e du l e a l l o w s a d d i t i o n a l t i m e t o c o n du c t p i l o t 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 H GS.

2 Based on average annual day ahead prices for 2 006 using SP

- 15 CAISO real

- time data.Addendum To The 316(B) Evaluation Of The H arbor Generating Station

2 - 4 As in 2004, f

ish protection technologies were considered to have potential for application at H GS if:

 The technology has proven biological effectiveness;

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

 The technology has engineering and/or biological advantages ov er the other technologies we evaluated. Table 2

- 3 is a revision to Table 3

- 1 from the initial evaluation.Addendum To The 316(B) Evaluation Of The H arbor Generating Station

2 - 5 T ABLE 2 - 1. P ERTINENT P ROJECT D ATA ( R EVISED T ABLE 2 - 1 FROM THE I NITIAL R EPORT ) Location 161 Island Ave, Wilmington CA, 90774 L a t i t u d e : 3 3

. 7 6 7 2 ° N L o n g i t u d e : 1 1 8

. 2 6 6 1 ° W Waterbody: Inner Los Angeles Harbor (ILAH ) Waterbody T ype: Embayment EPA ID #: DUT1138 NPDES ID #: CA0000361 Permit Expiration Date: June 10, 2008 Estimated project intake flow Maximum: 167 cfs (75,000 gpm) Minimum: 83.5 cfs (37, 500 gpm) Plant Design: 167 cfs (75,000 gpm) Intake velocities: (approach) One Pump Trash racks: 0.2 ft/sec Traveling water screen: 0.4 ft/sec (2 screens in operation) Traveling water screen: 0.2 ft/sec (4 screens in operation) Two Pumps Trash racks: 0.3 f t/sec Traveling water screen: 0.8 ft/sec (2 screens in operation) Traveling water screen: 0.4 ft/sec (4 screens in operation) Water Level Elevations HWL: El. 7.5 ft MLLW: El. 0.0 ft LWL: El.
- 1.7 ft MSL: El. 2.9 ft Water Depths In front of CWIS Maxim um: 42.5ft Minimum: 33.3ft MMLW: 35 ft MLS: 37.9 ft Other info rmation : all elevations refer to mean sea level Project Structures CWIS Location: Slip 5 L.A. Harbor Configuration: along shoreline Length: 56 ft Invert at face: El.
- 21.0 ft. Top: El:
- 11.0 ft Trash rack location: face of intake Trash rack material: 3/8 in. x 3 in. bars Trash rack spacing: 4.5 in. on
- center Trash rack cleaning: weekly or when neededAddendum To The 316(B) Evaluation Of The H arbor Generating Station

2 - 6 Table 2 - 1 . Continued Intake Pipes Number: 2 Length: 1,095 ft Inner diameter: 8 ft Invert: E l.
- 20.0 ft (CWIS) Invert: El.
- 16.0 ft ( screenhouse) Screenhouse Location: about 33.5 ft downstream of intake pipes Number of bays: 6 Bay width: 7.9 ft Invert: El.
- 16.0 ft Top of structure: El. 12.0 ft Other info: 2 bays permanently blocked, 2 bays are temporarily blocked and 2 bays are used during normal operations. Traveling water screens Location: screenhouse Number: 4 (only 2 operational) Width: 6.2 ft Mesh material: bronze Mesh size and geometry: 3/8 in. up to 5/8 in. sq. mesh Spray nozzle co nfiguration: back wash Spray pressure: 70 psig Spray volume: 800 gpm (2 pumps at 400 gpm) Operation: rotated for 30 minutes every 8 hour shift Debris/fish return: rectangular trough Troug h discharge: back into the ILAH Circulating water pumps Number of p umps: 2 Types of pumps: vertical, single
- speed, mixed
- flow Pump inlet: El.
- 14.5 ft Invert:
- 19.0 ft Rating: 305 hp @ 514 rpm Flow per pump: 83.5 cfs (37,500 gpm) Flow with both pumps operating: 167 cfs (75,000 gpm) Cooling water discharge Location of discharge: cooling water is transported through a 1,393 ft long pipe to the d i s c h a r g e s t r u c t u r e i n L

. A

. H a r b o r ’ s W e s t B a s i n , p r e v e n t i n g r e c i r c u l a t i o n
. Power Generation Fuel type: gas Facility output Units 1&2: 80 MW (each) Unit 5: 75 MW Unit 10
- 14: 43 MW (each) Facility total: 450 MW Operating mode: peaking Plant capacity factor: Unit 5: 23% (2001
- 2005) Average annual energy: 144,998 MWh (net) (2001
- 2005) (Unit 5)Addendum To The 316(B) Evaluation Of The H arbor Generating Station

2 - 7 T ABLE 2 - 2. R EVISED T ABLE 2 - 3 FROM THE I NITIAL E VALUATION – C OMPARISON OF P ERCENT

C OMPOS ITION OF E NTRAINED L ARVAE L ENGTHS C OLLECTED AT HGS Percent Composition * Species 2006

Entrainment 0 - 5mm 5 - 10mm 10 - 15mm >15mm anchov y 1 % 19 % / 3 % 28 % / 25 % 33 % / 42 % 20 % / 30 % gobies 81 % 86 % / 83 % 7 % / 17 % 7 % /
-- <1 % /
-- blenny 3 % 100 % / 100 % <1 % / < 1 %
-- /
-- -- /
-- white croaker 13 % 97 % / 96 % 2 % / 4 % 1 % /
-- -- /
-- * (1981 / 2007) References : Intersea Research Corporation (IRG), Harbor Generating Station Cooling Water Intake Study 316(b) Demonstration Program 1978

- 1979. (1981) Tenera Environm ental, IM&E Characterization Study Preliminary Results 2006 , unpublished. (2007)A ddendum To The 316(B) Evaluation Of The Harbor Generating Station

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

Effectiveness Proven Engineering

Alt ernative Available Advantages

over Other Concepts Potential for

Application at HGS Comments Behavioral Barriers Sound yes yes no no The focus of recent fish protection studies involving underwater sound technologies has been on the use of new types of low and high frequency acoustic systems that have not previously been available for commercial use. Sound devices are not appropriate for entrainment reduction as the early life stages have not yet developed hearing capabilities or have insufficient sw imming 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 fi sh to particle motion. Sound devices are not appropriate for entrainment reduction as the early life stages have not yet developed hearing capabilities or have insufficient swimming capability to avoid entrainment.A ddendum To The 316(B) Evaluation Of The Harbor Generating Station

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

Effectiveness Proven Engineering

Alt ernative Available Advantages

over Other Concepts Potential for

Application at HGS Comments Strobe lights yes yes no no Although many studies have evaluated strobe lights as a primary barrier system, strobes are often evaluated as part of an integrated fish protection and passage system that includes other devices such as screens, narrow
- spaced bar racks, bypasses, and/or other beh avioral 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

. Mercury lights no yes yes no Response to mercury light has been shown to be species
- specific; some fish species are attracted, others repelled, and others have demonstrated no obvious response. However, they are not effective with larval fish that have little or no motility

. Chemicals no no n o no Use of chemicals h as been suggested, and in some cases evaluated, as fish protection measures. However, no practical application of these devices has been developed, and they are not considered available technologies for application at CWISs.A ddendum To The 316(B) Evaluation Of The Harbor Generating Station

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

Effectiveness Proven Engineering

Alt ernative Available Advantages

over Other Concepts Potential for

Application at HGS Comments
Elect ric screens no yes no no Electric barriers have been shown to effectively prevent the upstream passage of fish. However, attempts to divert or deter the downstream movement of fish have met with limited success. Consequently, past evaluations have not le d to permanent applications. The potential effectiveness of these barriers for application at CWISs is unknown. Given their past ineffectiveness and hazard potential, electric screens are not considered a viable technology for application at CWISs. As w ith other behavioral barriers, electric barriers would not be effective with larval fish that have little or no motility

. Air bubble curtain yes yes no no These curtains generally have been ineffective in blocking or diverting fish in a variety of field applications. Air bubble curtains have been evaluated at number of sites on the Great Lakes with a variety of species. All air bubble curtains at these sites have been removed from service. Air bubble curtains would not be effective with larval fish tha t have little or no motility

. Water jet curtain no yes no no Devices such as water jet curtains have been suggested, and in some cases evaluated, as fish protection measures. However, no practical application of these devices has been developed, and the y are not considered available technologies for application at CWISs.A ddendum To The 316(B) Evaluation Of The Harbor Generating Station

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

Effectiveness Proven Engineering

Alt ernative Available Advantages

over Other Concepts Potential for

Application at HGS Comments 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 de vices has been developed, and they are not considered available technologies for application at CWISs. In addition, they are not effective with larval fish that have little or no motility

. Visual keys no yes no no V isual cues have been suggested, and in some cases evaluated, as fish protection measures. However, no practical application of these devices has been developed, and they are not considered available technologies for application at CWISs. Hybrid barriers (e.g., strobe light /air bubble curta in) no no no no N o practical application of these devices has been developed, and they are not considered available technologies for application at CWISs. In addition, they are not effective with larval fish that have little or no motility

. Physical Bar riers 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.A ddendum To The 316(B) Evaluation Of The Harbor Generating Station

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

Effectiveness Proven Engineering

Alt ernative Available Advantages

over Other Concepts Potential for

Application at HGS Comments Conventional t raveling water screens yes yes no no As barrier devices, traveling screens cannot be considered for protection of early life s tages 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 ye s yes no no B arrier nets can be considered a viable option for protecting adult fish provided that relatively low velocities (generally less than 1 feet/sec) can be achieved and debris loading is light. They would be ineffective with early life history st ages 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 redu ce 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 screeni ng large flow volumes or for CWIS application. Porous dike yes yes no no Rock structures such as rock cribs and porous dikes allow water to pass while preventing passage of juvenile and adult fish. Their effectiveness with larval fish is unknown.A ddendum To The 316(B) Evaluation Of The Harbor Generating Station

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

Effectiveness Proven Engineering

Alt ernative Available Advantages

over Other Concepts Potential for

Application at HGS Comments Aqua tic 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 HGS

. Cylindrical wedgewire screen intakes yes yes yes yes Wedgewire screens have the potential to reduce both entrainment and impingement at water intakes. Effectiveness is based on the slot size, through
- slot velocity, and presence of an ambient cross
- current to carry o rganisms and debris away. Collection Systems Modified traveling (Ristroph
- type ) screens (coarse
- and fine
- mesh) with fish protection features yes yes yes yes Modified traveling water screens continue to be an available technology that can reduce fi sh 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 screens. Depending on species and life stage, mortality from imp ingement can exceed entrainment mortality. Biofouling potential must also be considered.A ddendum To The 316(B) Evaluation Of The Harbor Generating Station

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

Effectiveness Proven Engineering

Alt ernative Available Advantages

over Other Concepts Potential for

Application at HGS Comments Fish pumps yes yes no no Hidrostal and Archimedes screw pumps have demonstrated an ability to transfer adult fish with little or no mortality. These pumps by thems elves 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. Divers ion 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. Angled screens (fixed or traveling) yes yes no no Angled screens can be considered a viable option for protecting juvenile and adult life stages provided that proper hydraulic conditions can be maintained and debris can be effectively removed. Fish eggs, larvae, and small invertebrates would not be protected by angled screens unless fine
- mesh s creening 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 require a n even larger are a than “ 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 HGS

.A ddendum To The 316(B) Evaluation Of The Harbor Generating Station

2 - 15 T ABLE 2 - 3. I NITIAL S CREENING OF F ISH P ROTECTION A LTERNATIVES AT HGS ( R EVISED T ABLE 3 - 1 FROM THE I NITIAL E VALUATION ) Concept Biological

Effectiveness Proven Engineering

Alt ernative Available Advantages

over Other Concepts Potential for

Application at HGS Comments
Eicher screen yes yes no no While biologically effective, the Eicher s creen was designed for penstock and pipes. There is no advantage over an MIS at HGS

. Modular inclined screens (MIS) yes yes no no The combined results of laboratory and field evaluations of the MIS have demonstrated that this screen is an effective fish diversion device that has the potential for protecting fish at water intakes. Any consideration of the MIS for CWIS application should be based on future large
scale, prototype evaluations. Due to the slot size (2.0 mm) s ome reduction in entrainment can be expected. Submerged traveling screens no yes no no Designed for partial screening of hydroelectric project intakes. No t applicable to HGS

. Modifications to Reduce Intake Flow Modified pump operation yes yes no no Reducing flow will reduce impingement and entrainment. Flow reduction could be accomplished by either turning pumps on and off or with the installation of VSDs to follow the load (see below). HGS has only one unit that uses once - through cooling . T his unit operated off the waste heat from two other units, therefore reducing the output of Unit 5 would red uce the output of the two associated units.A ddendum To The 316(B) Evaluation Of The Harbor Generating Station

2 - 16 T ABLE 2 - 3. I NITIAL S CREENING OF F ISH P ROTECTION A LTERNATIVES AT HGS ( R EVISED T ABLE 3 - 1 FROM THE I NITIAL E VALUATION ) Concept Biological

Effectiveness Proven Engineering

Alt ernative Available Advantages

over Other Concepts Potential for

Application at HGS Comments
Install VSDs yes yes no no Due to the existing low velocities within the HGS CWIS , VSDs would not provide any additional benefit by reducing the intake velocity. Some reduction in entrainment could be achieved with VFDs as a result of reduced intake volume. Install closed
- cycle cooling system (mechanical , natural draft and dry cooling towers) yes yes yes yes Closed
- cycle cooling will reduce flow significantly. Depending on the type of closed
cycle system ins talled and the maximum number of cycles
- of
- concentration, circulating water flow in salt water could be reduced 73
- 98 percent

. Impingement and entrainment would be reduced accordingly.Addendum To The 316(B) Evaluation Of The Harbor Generating Station

3 - 1 

## 3.0 ENTRAINMENT REDUCTIO N OPTIONS As stated previously, compliance with 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 cooling water flow by limiting station operations are extreme and costly measures. There are limited technologies th at can be considered for reducing entrainment and even more limited information of the effic acy of these technologies with West C oast marine or estuarine species. Fine

- mesh traveling screens (e.g. , Ristroph

- type, Hydrolox, or Geiger) have potential for app lication at HGS. There are currently no additional data available on the effectiveness of these screens in reducing mortality of entrainable organisms. 

### 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 t i o n r e f l e c t e d a n ap p r o a c h v e l o c i t y o f 0

. 2 feet per second ( ft/sec ) . The actual velocity is about 0.8 ft/sec as only two of the six screenbays are in operation. With 4 traveling water screens in operation, this velocity is reduced to about 0.4 ft/sec. This velocity falls within the range that Al den uses to design fine

- mesh fish protection screens, therefore the fine

- mesh Ristroph screen option as described in the 2004 evaluation will not change. Due to the layout of the screenbays and the location of the circulating water pumps , there may not b e balanced flow through the fine

- mesh screen s . This could lead to excessive fouling of the higher velocity screens and result in lower survival of entrain ed organism s. To reduce this potential , LADWP sh ould consider having a hydraulic model developed. Ha ving reviewed the 2006 entrainment characterization study results for HGS, Alden now believes that survival of the earliest life history stages of fish entrained at HGS will be negligible. These life stages dominate the entrainment numbers and, therefore, this technology would probably not meet the entrainment reduction standard. However, Alden recommends that pilot studies be conducted if LADWP wants to consider this technology further. The pilot study proposed for HGS would identify where survival of p reviously entrained organisms starts to occur. LADWP has requested a prediction of the size mesh required to effectively exclude larval fish at HGS. The key factor in exclusion of aquatic organisms is the maximum dimension of the organism. Typically, hea d capsule depth (HCD) is selected as it is the earliest

- developed , non - compressible body part. Unfortunately, Alden could not find adequate data on the West Coast species of interest at H GS to develop the necessary analyses. However, adequate data have b een developed for East Coast 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) FOR L ARVAE C OLLECTED AT HGS West Coast Species Length at hatch ( mm) East Coast Species Predicted HCD (mm) Gobiidae 2.7
- 3.2 Naked goby 0.56 Hypsoblennius 2.0 Atlantic menhaden 0.83 California halibut 1.6
- 2.1 Bay anchovy 0. 30 White croaker 2.2
- 2.8 Bay anchovy 0.37 Northern anchovy 2.5
- 3.0 Bay anchovy 0.34Addendum To The 316(B) Evaluation Of The Harbor Generating Station

3 - 2 The dat a used for this assessment are provided in Attachment D . Based on the above information, a nominal mesh size of 0.3 mm would be required to exclude California halibut yolk

- sac larvae. However, to be conservative , a 0.2 mm mesh screen was selected to excl ude larvae found at HGS. 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 associ ated with the replacement of the existing 9.5 mm mesh screens with 0.2 mm screens:

 Increase head loss

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

 Screen rotation speed

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

 Screen mesh

– A 0.2 mm screen mesh will require a 1

- inch back up mesh for added s trength. 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 re duce 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 t h 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. To prevent reimpingement of the fish and debris , the return would need to be routed along the discharge pipe. As a result , organisms collected from the screens will have to be transported about 1,400 feet through a return pipe. In addition, fish and shellfish species and their associated life stages tend t o vary considerably in terms of their ability to tolerate the collection and handling associated with this option, which emphasizes the need for species and life stage specific testing to verify survival rates. Alden believes that there are methods for ma intaining a clean fish return system. A review and comparison of two potential fish return cleaning systems is provided in Attachment E

. Finally, concern has been expressed with biofouling of the exposed (above water surface) screening components during c ontinuous operation of the screen. Although this may be a valid concern, an assessment could easily be performed during a pilot study. Development of a fouling control technology could be a component of the pilot study. However, rather than confound the biological assessment component of the study, it may be desirable to conduct a small

- scale, focused study for evaluating biofouling conditions. Costs for this component of a pilot study have not been developed. Conclusion Fine

- mesh traveling screens are 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 o l o g y ” t h a t u t 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 o f c o l l e c t i n g o r g a n i s m s t o a s s e s s s u

r v i v a l i m p a rt s s o m e l e v e l o f mortality , which is difficult to ascertain in the field. Consequently, the projected efficacy of this technology will be less than that for other exclusion technologies that do not collect the organisms

. The life stages that dominate the entrainment numbers at HGS are such that this technology would probably not meet the entrainment reduction stan dard.Addendum To The 316(B) Evaluation Of The Harbor Generating Station

3 - 3 

### 3.2 R ETROFIT 

### I NTAKE WITH 

### 0.5 MM 

### W EDGEWIRE 

### S CREENS Narrow

- slot cylindrical wedgewire screens could be installed to reduce fish entrainment and impingement. Cooling water would be conveyed through submerged, cylindrical wedgewire screens mounted on a b ulkhead wall in front of the existing CWIS. The bulkhead would be constructed to form a common plenum in front of the existing intakes. Thirty T

- 36 screens would be mounted on this wall in three rows of 10 screens. An air backwash system was originally included to clean the wedgewire screens. The effectiveness of this cleaning method is contingent on the local tidal currents ability to transport debris flushed away from the screens. Based on further research , the tidal flow in the ILAH is not expected to be sufficient to transport fish and debris from the screens. As a result , alternative methods of cleaning the screens would be necessary. One method to reduce biofouling is to use J o h n s o n S c r e e n ’ s Z

- alloy, a nickel

- copper alloy material. T his would require nine additional screens and would more than double the cost per screen. In addition to the new material , a method for removing debris from the screens would be necessary. This could be done by removing and cleaning the fouled screens on the CWIS deck or manual cleaning of the screens by divers

. Conclusion If the screens c ould be maintained , the efficacy of this technology would be high and has potential to significantly reduce entrainment and meet the entrainment reduction performance standards

. 

### 3.3 F LOW 

### R EDUCTION Using Variable Speed Drives (VSDs) would be an effective method to reduce flow. The VSDs would allow much finer control of flow reductions , while ensuring adequate flow to meet heat rate and generation needs. The level of the reductio n achievable with VSDs, without effecting generation, would vary depending on load and inlet water temperature. The maximum reduction associa ted with VSDs would be about 40 percent

. A flow reduction of 40% would not meet either the impingement or entrain ment standard, but could be used to in conjunction with another technology to meet the standard s . If LADWP were to install VSDs on the circulating water pumps a detailed, design review of condensers, circulating water pumps, motors, and piping would need to be conducted to identify potential issues associated with VSDs. Some key operational issues that would need to be addressed are: unbalanced pump operation if a VSD is placed on only one pump, loss of pressure in the condenser waterboxes, vibration of t he pumps at lower speeds, and potential to burn out the existing motors. This review will further identify the limitations that may exist and provide recommendations for each unit upgrade. The cost to install VSDs on all the circulating water pumps is in cluded in the cost section. The following upgrades are not included in our cost estimate; but would be required prior to installing VSDs:

 Installation of a back

- pressure valve on the condenser discharge;

 Installation of pump discharge valves;

 New circulat ing water pumps; and

 New pump motors.Addendum To The 316(B) Evaluation Of The Harbor Generating Station

3 - 4 HGS currently has only one unit, Unit 5 , operating with once

- through cooling. Unit 5 operates off of waste heat from Units 1 and 2. Unit s 3 and 4 have been retired and Units 10

- 14 are simple

- cycle turbines with cooli ng towers. If credit can be taken for d esigning Units 1, 2 and 10

- 14 without once

through cooling the entrainment reduction standard will be met

. Conclusion Consideration of flow reduction remains a possible alternative. Typically, flow reductions, if they affect generation , would need to be discussed with Corporate Power Supply. Assessment of general trends in load demand can predict periods where running at reduced loads or placing a unit(s) on standby would not affect reliability of the plant. Thes e flow reductions would result in some flow reduction credit. Due to the already low intake velocities at HGS , VFDs would not provide any additional benefits associated with reducing the velocity. During periods of high demand and high water temperatures , reducing flow may result in the need to de

- rate the unit(s) to maintain thermal discharge limits. Use of VSDs could be considered to better control flow reductions and minimize lost generation. Costs for VSDs have been included in this Addendum. Regar dless, this option by itself would not likely meet the entrainment reduction standard. 

### 3.4 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 evaluatio n 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 Ru le , 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 , it would be 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 h

n 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 Clo sed

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

- cycle cooling will be required to meet the standard is not know at this time. Cooling towers would have the highest overall capital and operating and maintenance ( O&M ) cost o f all of the alternatives 

### 3.5 A DDITIONAL 

### T ECHNOLOGIES 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 entrainment of larger entrainable organisms. Results of species

- specific survival from pilot studies of both the fine

- mesh traveling screens and the MIS could be compared to develop overa ll efficacy. All the ancillary issues , such as transport to a safe location in the source waterbody, associated with fin e - mesh screens apply to the MIS. Additionally , the traveling water screens would need to be left in place and operational to collect de bris from the screen when i t is rotated for cleaning. Bio fouling of the screen mesh may also be an issue . T herefore, the Z

- alloy as described in the narrow

- slot , wedgewire section could be used to prevent bio

- fouling of the screens. Alden recommends a p ilot study to determine the biologic effectiveness and gage the bio fouling if MIS are to be considered for full

- scale application at HGS . MIS units have not been tested with slot sizes smaller than 2.0 mm; however , the design of the MIS could be modified to accept a smaller slot size. Any changes in meshAddendum To The 316(B) Evaluation Of The Harbor Generating Station

3 - 5 size would need to be tested prior to full

- scale application. If the MIS proved effective , and biofouling issues were resolved during the pilot tests, then the MIS could be a good option at HGS. Conclusi on 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

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

- mesh screen options. Alden does not believe that MIS with 2.0 mm slot size will meet the entrainment reduction standard; however, a n MIS with a smaller slot size may be able to meet the standard. The results of the pilot study will remove this uncertainty. The ultimate cost of the systems would dictate the technology selection.Addendum To The 316(B) Evaluation Of The Harbor Generating Station

4 - 1 

## 4.0 IMPINGEMENT MORTALIT Y REDUCTION OPTIONS A s s t a t e d p r e vi o u s l y, t e c hn o l o g i e s c o n s i de r e d f o r c o m p l i a n c e w i t h E P A ’ s e n

t r a i n m e n t r e d u c t i o n performance standards would also be applicable for the impingement mortality reduction standards. Technologies that would reduce only impingement were not evaluated in the 2004 evaluation for HGS

. However , after reconsideing options for HGS , there are several technologies that cou ld be used to reduce impingement mortailty. 

### 4.1 C OARSE 

### - MESH 

### M ODIFIED 

### T RAVELING 

### S CREENS Coarse

- mesh modified traveling screens could be used at HGS to reduce impingement mortality. The existing screen approach velocity with two screenbays in ope ration and at mean low water level is about 0.8 ft/sec at full flow. F or many species , t his velocity is within the range of velocities that has demonstrated good survival with traveling screens that been modified for fish protection at other facilities (Ristroph screen 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

rv i v a l d at a e x i s t f

o r s p e c i e s impinged at HGS. Therefore, Alden still recommends conducting pilot studies before any further consideration of full

- scale installation. A pilot study proposed for HGS would identify where survival of previously entrained organisms starts to occur. To prevent reimpingement of the fish and debris, the return would need to be routed along the discharge pipe. As a result, organisms collected from the screens w ould have to be transported about 1,400 feet through a return pipe. In addition, fish and shellfish species and their associated life stages tend to vary considerably in terms of their ability to tolerate the collection and handling associated with this option, which emphasizes the need for species and life stage specific testing to verify survival rates. Alden believes that there are methods for maintaining a clean fish return system. A review and comparison of two potential fish return cleaning systems is provided in Attachment E. Conclusion Coarse

- mesh modified traveling screens are a viable alternative for impingement mortality reduction. Alden is uncertain if this standard could be met with the species present at HGS and, therefore, recommends that a pilot study be conducted if this alternative is considered further. 

### 4.2 W IDE 

### - SLOT 

### C YLINDRICAL 

### W EDGEWIRE 

### S CREENS LADWP could install a wide

- slot cylindrical wedge wire screen intake at HGS to reduce fish impingement. Two stainless steel , T

- 84 screens with 9.5 mm slot opening s would be required to accommodate the total facility flow. These screens would be mounted onto a bulkhead wall similar to the narrow

- slot option. The design through slot velocity would be about 0.5 ft/sec with clean screens. The screens would be angled so that they we re parallel to the predominant currents in the area. The effectiveness of an air backwash system to clean wedgewire screens is contingent on the presence of local tidal currents to transport debris flushed away from the screens. Based on availab le information , the tidal flow in the ILAH is not expected to be sufficient to serve this purpose . As a result, alternative methods of cleaning the screens would be necessary. Installing an extra screen at HGS would allow LADWP to sequentially remove eac h wedgewire screens for cleaning without increasing the through mesh velocity above 0.5 ft/sec. A second method to reduce biofouling is to u s e J o h n s o n S c r e e n ’ s Z

- alloy, a nickel

- copper alloy material. This approach would not require any additional screen s but would more than double the cost per screen.Addendum To The 316(B) Evaluation Of The Harbor Generating Station

4 - 2 Conclusions Wide

- slot cylindrical wedgewire screens would meet impingement standard via Compliance Alternative 1. Since an air backwash system is not expected to be effective at HGS , Alden has include d costs for a third screen to allow for manual cleaning. 

### 4.3 F LOW 

### R EDUCTION P r i o r t o th e 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 a llow facilities to assume proportionality between flow and impingement. As with entrainment, flow reduction remains an alternative but can only be considered in conjunction with another technology. That is, the curtailment in generation required to meet the remanded impingement mortality reduction standard of 80

- 95% using flow reduction alone is not practica b l e or cost

- effective. Conclusion Consideration of flow reduction remains a possible alternative. Typically, flow reductions need to be discussed wit h Corporate Power Supply. Assessment of general trends in load demand can predict periods where placing Unit 5 on stand

- by would result in some flow reduction credit. Shutting off pumps during high periods of impingement would result in the need to de

- ra te the unit to maintain thermal discharge limits. Use of variable speed drives could be considered to better control flow reductions and minimize lost generation. Costs for variable speed drives have been included in this addendum. Regardless, neither o ption would likely meet the impingement mortality reduction standard. 

### 4.4 C LOSED 

### - C YCLE 

### 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 res ults of this evaluation will identify the economic penalties associated with this option. Conclusion Closed

- cycle cooling will meet all performance standards. However, Alden does not believe it is reasonable to consider it for impingement only. 

### 4.5 A DDITIONAL 

### I MPINGEMENT 

### R EDUCING 

### T ECHNOLOGIES As with consideration of additional entrainment reduction alternatives, there are other impingement reduction alternatives that have been suggested to be considered. Passive screening (e.g. coarse

- mesh barrier nets) requ ires low through

- net velocities to exclude fish. This type of technology would have to be placed in the ILAHC where it could interfere with other commercial activities. Therefore, Alden does not consider a passive screening system to be a viable alternat ive for HGS. Conclusion Although impingement

- only alternatives are available, Alden does not recommend further consideration of impingement

- only options in light of the Second Circuit Court Decision.Addendum To The 316(B) Evaluation Of The Harbor Generating Station

5 - 1 

## 5.0 COST UPDATE The revised costs presented in Table 5

- 1 ar e an update of the estimated costs provided in Table 6

- 3 of the original report. The update includes an escalation from 2002 dollars to 2006 dollars , as well as changes in the site

- specific factors that impact the installation and O&M of the compliance al ternatives. Estimated costs for installing a MIS , VSDs and impingement only technologies at HGS have been added to this table. These costs were calculated using the same costing methodology as used in the 2004 evaluation.Addendum To The 316(B) Evaluation Of The Harbor Generating Station

5 - 2 T ABLE 5 - 1. A LDEN ’ S A PPRAISA L L EVEL C OSTS OF E VALUATED A LTERNATIVES

Estimated from Alden Database

Alternative Construction Costs (2006 $) Replacement

Power During Shutdown (MWh) Total

Capital Cost (2006 $) 1 O&M

Costs (2006 $) Lost

Generation (MWh) 2 Annualized

Capital Costs (2006 $ ) 3 Incremental

Annualized O&M Costs (2006 $) 1, 2 Total

Incremental Annualized Costs (2006 $) Retrofit Screenhouse with Fine
- mesh Ristroph Screens $1,859,000 0 $1,859,000 $235,000 1,051 $265,000 $274,000 $539,000 Install Narrow
- slot Wedgewire in front of the Existing CWIS $2,397,000 0 $2,397,000 $549,000 0 $341,000 $535,000 $876,000 Modular Inclined Screen in the Existing Intake $2,486,000 0 $2,486,000 $19,000 270 $354,000 $33,000 $387,000 Install VSDs on the Circulating Water Pumps $652,000 0 $652,000 $0 0 $93,000 $0 $93,000 Retrofit Screenhouse with Coarse
- mesh Ristroph Screens $1,080,000 0 $1,080,000 $120,000 526 $154,000 $132,000 $286,000 Install Wide
- slot Wedgewire in front of the Existing CWIS $1,387,000 0 $1,387,000 $289,000 0 $197,000 $275,000 $472,000 Existing Operations $0 0 $0 $0 0 $0 $0 $0 Retrofit Plant with Closed
c ycle Cooling System 4 $16,800,000 105,000 $22,050,000 $336,000 4,610 $2,815,000 $553,000 $3,368,000 1. Based o n a cost for lost generation of $50 per MWh

. 2. Includes costs as a re sult 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 down time costs

. 4. Cooling tower costs based on EPRI study (EPRI 2 002a)

.A ddendum To The 316(B) Evaluation Of The Harbor 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 exa cerbated by the variability of the biological community characteristics (e.g. diel/seasonal abundance, life stage, species) at the site. Table 6

- 1 provides a summary of these uncertainty considerations for each of the alternatives considered in 2004 and in this document for H GS.

T ABLE 6 - 1. A LTERNATIVE D ATA G APS AND U NCERTAINTIES Alternative Data Gaps Uncertainties Fine
- mesh Traveling Screens  Length and species

- specific survival data from the screen and fish return line; and

 Biofouling impacts ;
 Near sho re return survival.  Effective mesh size;

 Effective approach velocity; and

 Annual variability in species composition. Narrow
- slot Wedgewire Screens  Length and species

- specific exclusion data; and

 Biofouling impacts

.  Effective mesh size;

 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 ;
 Annual variability in species composition ;
 Biofouling; and

 Effective cleaning method. Modular Inclined Screens  Length and species

- specific survival data from the screen and fish return line; and

 Biofouling impacts ;
 Near shore return surviv al;

 Only 2.0 mm slot width has been tested.  Effective mesh size;

 Effective approach velocity; and

 Annual variability in species composition.

Flow Reduction  Reasons for installing combined cycle units

 Seasonal species distribution and relative abundance.  C alEPA acceptance of pre

existing flow reduction

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.

W ide
- 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. Closed
- cycle Cooling  Unit

- specific retrofit; and

 Available space.A ddendum To The 316(B) Evaluation Of The Harbor Generating Station

6 - 2 The data gaps that exist with spe cies composition, survival, and diel/seasonal presence and variability 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 stati on effects

. The pilot studies proposed for HGS (fin e - mesh traveling screens) and Haynes Generating Station (Hn GS ) (MIS) will provide data on length

- related, species

- specific survival. Macrofouling on the continuously operating screens can be determined d uring the pilot studies , as well as debris handling capabilities. Macrofouling and subsequent predation on entrained organisms could be assessed during a pilot study. However, a more prudent approach would be to develop an effective return line treatment technique based on actual plant operating data. Pilot studies could also reduce the uncertainties of the effects of mesh size and approach velocities on organism survival. These issues, however, would probably be best determined after results from the ab ove studies were available. The uncertainties associated with annual variability in species abundance and composition as they relate to the ability to meet performance standards cannot be reduced by pilot studies. It is anticipated th at s u rv i v a l a m 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

.A ddendum To The 316(B) Evaluation Of The Harbor Generating Station

7 - 1 

## 7.0 C ONCLUSIONS This assessment indicates that:

 Replacing the original once

- through units at HGS with combined

- cycle units resu lts in a theoretical flow reduction of 68 percent. If LADWP can document that the decision to use combined

- cycle units was done in part for ecological reasons then they may be able to take credit for dramatically reducing impingement and entrainment.

 T he 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 bris returns as Ristroph screens. The potential use of either of these 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 redu cing entrainment at HGS. The overall efficacy of any entrainment reduction technology is mitigated by the predominance of very early life history stages.

 The C o u r

t ’ s D e c i s i o n to remand restoration and the cost

- benefit test severely limits 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 assessments.

 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 cont inue to consider additional options.

 Conclusions for entrainment:

 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 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 hn o l o g y . ” However, unlike narrow - slot wedgewire screens that depend on an air

- burst cleaning system , coupled with a m b i e nt c u r r 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 technolo 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 o f c o l l e c t i n g o r g a n i s m s t o 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 tha t for narrow

slot wedgewire screens.

 As with the fine

- mesh traveling screens , the projected efficacy of MIS will be less than that for narrow

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

- mesh screens, this alternative m ay be as effective as the other fine

- mesh screen options.

 Effective methods to clean the narrow

- slot wedgewire screens would need to be determined prior to any full

- scale application.

 If EPA does not designate closed

- cycle cooling as BTA, pilot studies w ould 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 .A ddendum To The 316(B) Evaluation Of The Harbor Generating Station

7 - 2  Conclusions for impingement only:

 Coarse

- mesh traveling screens are still a viable alternative for impingement mortality reduction.

 Wide

- slot wedgewire screens would me et the impingement mortality standard; however an effective method of cleaning the screens would be needed prior to consideration for full scale application.

 Consideration of flow reduction remains a possible impingement mortality reduction alternative. The same comments previously discussed for entrainment reduction apply to this alternative.

 Although impingement

- only alternatives are available, Alden does not recommend further consideration of impingement

- o n l y o p t i o n s i n l i g h t o f th e C o u rt ’ s D e c i s i o n .Attachment A Addendum To The 316(B) Evaluation Of The Harbor Generating Station

1 

## ATTACHMENT A - SUMMARY OF 2004 EVAL UATION OF HGS The following provides a summary of the “ E v a l u a t i o n o f t h e Harbor Generating Stations with respect t o th e E n v i r o n m 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 2 0 0 4 , prepared by Alde n Research Laboratory, Inc. (Alden) and EPRI

. Scope of the Analysis In response to the Rule, Electric Power Research Institute (E PRI) and Alden conducted a strategic assessment for Los Angeles Department of Water and Power (LADWP) Harbor Generating St ation (HGS) . This assessment evaluated the impact of the Rule on HGS, including potential cost

- effective compliance alternatives, additional information collection needs, and relative budget impacts as a result of studies and compliance alternatives. Th e major component of this analysis was a preliminary evaluation of alternative fish protection technologies to meet the applicable performance standards for HGS and discussion of approximate costs for the feasible alternatives. As part of this alternative s analysis, Alden reviewed operational options for meeting the applicable performance standards. This report addressed technologies, operational changes, and restoration measures that LADWP could implement to meet the Rule. The U.S. Environmental Protec t i o n A g e n c y ’ s ( E P A ’ s ) favored approach was to reduce total fish losses, which did not address AEI at the population and ecosystem levels. Therefore, traditional measures of population and ecosystem health, such as species diversity and richness , were not addressed. Further, EPA did not consider factors that influence populations such as compensatory mechanisms, species fecundity, and natural mortality. Therefore, these factors were not considered. Technologies and Operational Measures The preliminary ev aluation of alternative technologies and operational measures that could be considered by LADWP to meet the impingement mortality and entrainment ( IM&E ) standards at H GS wa s 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 atives we re to actually meet these sta ndards was summarized as follows :

Alternative Will It Meet t he Impingement Mortality Reduction Standard? Will It Meet t he Entrainment Reduction Standard? Fine
- m esh Ristroph Screens Yes, provided that impingement survi val of key species is at least 80 percent. Yes Narrow
- s lot Wedgewire Screens Yes Yes Existing Facility Operations Yes, the through screen velocity is less than 0.5 ft/sec

. Yes, if the existing operations provide a flow reduction of greater than 60% from a hypothetical baseline flow. Closed
- c ycle Cooling Yes YesAttachment A Addendum To The 316(B) Evaluation Of The Harbor Generating Station

2 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 Cost (2002 $) E P A ’ s A n n u a l i z e d C o s t s (2002 $) Fine
- m esh Ristroph Screens $486,000 Narrow
- s lot Wedgewire Screens $470,000 Existing Facility Operations $0 Closed
- c ycle Cooling $3,206,000 $ 130,007

Key findings of our preliminary (2004) analysis we re:
 The design and operation of Units 1 and 2, 5 and 10

- 14 may provide HGS with an 84% reduction in flow from a theoretical baseline if all eight units were designed and operated as once - through units. If only Units 1, 2, and 5 are considered, then the existing operations would result in a flow reduction of 68 pe rcent. Because flow and entrainment are directly proportional (assuming equal distribution of organisms), this flow reduction should reduce entrainment by greater than the 60% required by the Rule.

 The existing through

- screen velocity at the traveling wat er screens is less than 0.5 ft/sec during normal plant operations. HGS should automatically meet the impingement mortality reduction standard via Compliance Alternative 1due to this low velocity.

 Two technologi es ( i.e., fine

- mesh Ristroph screens and narr ow - slot wedgewire screens) and two operational options ( i.e., existing operations and closed

- cycle cooling) were considered to have potential for meeting the IM&E reduction standards and were deemed practicable from an engineering standpoint. As the exist ing CWIS should already meet the impingement mortality reduction standard, technologies that reduce only impingement mortality were not evaluated.

 Of the four options that could meet the entrainment reduction standard, Alden estimates the annualized cost s range from $0 for to maintain current operations to $3,206,000 for closed

cycle cooling.

 If the existing operations at HGS do not meet the IM&E standard, replacing the existing screens with fine

- mesh Ristroph screens or narrow

- slot wedgewire screens ha ve the greatest potential to meet the standards. The annualized costs for these technologies are $486,000 for fine

- mesh Ristroph screen and $470,000 for narrow

- slot wedgewire screens. The following general considerations were used to develop conceptual de signs of alternative fish protection technologies for application at HGS . 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 HGS. The criteria were:

 Alternatives should be designed to reduce impingement mortality by 80

– 95% from the
“ 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 “ c a l c u l a t i o n baseline. ”Attachment A Addendum To The 316(B) Evaluation Of The Harbor Generating Station

3  Alternatives should provide protection for species that are potentially susceptible to IM&E at HGS.

 The period of protection is year

- round for impingement and nine months for entrainment.

 Alternatives should take into consideration current project design features, as summarized in Table 2

- 1 in the Addendum 3

.  Alternative designs should have suitable conditions for fish protection over the full range of intake flows and water depths at the CWIS.

 Alternatives should provide effective protection throughout th e 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 harbor (i.e., reasonable cleaning techniques are available and d emonstrated).

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

 Alternatives should meet worker and public safety requirements.

 Alternatives should not adversely impact navigation.

 Alternatives should be compatib le 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 conditio ns that they have never been applied, the Team had to use best professional judgment based upon experience. The Team deemed a technology to have proven biological effectiveness if test data (preferably from full

- scale application) were available that docum 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 been constructed at another site, it was judged it to be an available technology. Each technology was qualitatively assessed to identify whether it had biological and/or engineering advantages over the other alternatives. For example, an intake technology that has been proven effective at reducing losses for many species and under a variety of intake conditions has a biological advantage over one that has been proven effective with a few species or under limited intake conditions. From an engineering perspective, one technology may hold an advantage over another i f the civil/structural requirements for its installation are substantially less. 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 t he results of laboratory and cage test studies that have demonstrated strong avoidance by several fish species to strobe lights. Strobe lights have been evaluated for repelling or guiding juvenile and adult fish away from water intakes (EPRI 1994, 1999) a nd, in many cases, toward bypasses for transport to a safe release location. There is some evidence that combining strobe lights with an air bubble curtain can provide effective fish deterrence. However, results have been species

- and site

- specific.

3 See Table 2

- 1 (Revised) for updated assessment.Attachment A Addendum To The 316(B) Evaluation Of The Harbor Generating Station

4 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 re peatedly repel members of the genus Alosa (American shad, alewife and blueback herring) at sites throughout the U.S. (Ploskey et al. 1995; Dunning 1995; Consolidated Edison 1994). Other studies have not shown sound to be consistently effective in repelling species such as largemouth bass, smallmouth bass, yellow perch, walleye, rainbow trout (EPRI 1998), gizzard shad, Atlantic herring, and bay anchovy (Consolidated Edison 1994). Based on the results of behavioral barrier studies conducted over the past 30 y ears, a hybrid barrier consisting of light, sound, and air bubbles would be most effective on Alosids. Little or no information is available on the potential effectiveness of a hybrid barrier with several of the numerically dominant species at HGS. Given that Alosids are absent from the fish assemblage impinged at HGS, a hybrid barrier would not reduce impingement to a level that meets the impingement mortality reduction standard and , thus , these types of barriers were removed from further consideration at HGS. The existing intake at HGS incorporate s 3/8 in. square mesh traveling water screens that would be relatively easy to modify for installation of Ristroph screens. Ristroph screens are very similar to conventional traveling water screens , except the y are designed with extra features to collect and transport impinged organisms safely back to the waterbody. Fine

- mesh Ristroph screens have the potential to meet both standards, while coarse

- mesh Ristroph screens may meet only the impingement mor t ality s tandard. In addition, Ristroph screens are designed for continuous operation to minimize impingement duration. Continuous rotation along with the associated spray washes provides Ristroph screens with an automatic screen

- cleaning feature. This gives the m an engineering advantage over fixed screens, barrier nets, and bar rack barriers, all of which would require an additional cleaning system. Fine mesh Ristroph screens can be considered a viable alternative for reducing both IM&E. If only the entrainmen t standard needs to be met at HGS , fine mesh screen overlays could be used. These screens would be more cost effective than Ristroph screens , as they would use the existing traveling water screens modified to accept a fine mesh screen material. However, these screens would not include the Ristroph fish handling and return components. Fine mesh traveling screens would meet the word of the Rule by significantly reducing entrainment numbers. Impingement mortality of entrainable organisms off of fine mesh tr aveling screens, however, is expected to be near 100% and would, therefore , have no net benefit. The Team does not expect E nvironmental P rotection A gency would accept changing an entrainment issue into an impingement issue. As a result , fine mesh travelin g screens are not considered a viable option for HGS. Modification of the screenhouse to incorporate physical barriers or other diversion systems to prevent entrainment and impingement mortality would be difficult. Rotary drum screens and porous dikes r equire a much larger area than conventional traveling screens because of the lower design velocity. Rotary drum screens are typically installed in channels where water elevations are relatively constant and water depths are less than 12 f ee t, which is les s than the water depth near the HGS intake. Bar rack barriers are typically designed to have spacing greater than 1 in. and would not be effective in preventing the entrainment of early life stages. They may, however, be effective at reducing impingement

. The Modular Inclined Screen (MIS) and Eicher screen have a biological and engineering advantage over louvers, angled bar racks, and angled screens in preventing impingement. Both screens offer the potential to effectively divert most species by using smaller structures than the other screen concepts. The MIS, for example, is designed to operate at velocities up to 10 ft/sec. However, the MIS has notAttachment A Addendum To The 316(B) Evaluation Of The Harbor Generating Station

5 been shown to protect larval fish, and the Eicher screen is designed for installation in hydroelectric project penstocks. Therefore, these diversion technologies are not applicable to HGS where impingement and entrainment are both of concern. The existing intake could be modified to incorporate cylindrical wedgewire screens, thus providing this technology with an engineering advantage over the porous dike, infiltration intake, and bar rack barriers ( Table 2

- 3 in Addendum ). Wedgewire screens also have cleaning features that give them an advantage over other fixed sc reens and barrier nets that are more difficult to maintain. This cleaning feature requires the presence of a sweeping current to be effective. 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, wedgewire screens have been included in the preliminary evaluation for HGS. Aquatic filter barriers (AFB s ) could perform a similar function to fine mesh traveling water screens. The AFB has an engineering advantage over barrier nets relative to cleaning ( Table 2

- 3 in Addendum ). An AFB has two layers of material with an air purge system installed between the layers to permit automatic cleaning of accu mulated silt and debris. This cleaning system can also free impinged fish larvae and other non

- motile life stages. The flow approaching an AFB is currently limited to10 gpm/ft 2 . HGS would require about 7,500 ft 2 of AFB to achieve this velocity. An AFB at HGS would have to be approximately 225 f ee t long, assuming a 33 f oo t average low water depth in front of the intake structure. Placing an AFB in the I nner L os A ngeles H arbor (ILAH) would interfere with shipping activities. Therefore, an AFB is not con sidered a viable alternative for preliminary evaluation for HGS. Fine mesh barrier nets (<0.5 mm) are easily fouled by silt and algae, require labor

- intensive cleaning, and are considered experimental for reducing entrainment at this time. However, coarse mesh nets could reduce impingement if they were installed in a low velocity zone and periodically cleaned to remove debris accumulation and biofouling growth. A barrier net at HGS, however, would have to be installed in the ILAH and would interfere with shipping in the channel. Additionally , the design through

- screen velocity of the existing traveling water screens appears to be less than 0.5 ft/sec, therefore automatically meeting the impingement mortality performance standard via Compliance Alternative 1. A barrier net is therefore not considered a viable alternative for preliminary evaluation at HGS. The preliminary screening of intake technologies available for fish protection ( Table 2

- 3 in Addendum ) indicate s that two intake alternatives have the greatest potential for application to reduce fish IM&E at HGS:

 Expanded intakes with fine mesh 4 Ristroph screens ; and

 Wedgewire screens with 0.5 mm openings

. Two flow reduction options were identified to reduce entra inment and, to a lesser extent, impingement:

 Existing reduced flow operation ; and

 Install an additional closed

- loop cooling system

.

4 T h e t e r m “ f

i n e m e s h , ” a s u s e d i n th i s d o c u m e n t , r e f e r s t o 0

. 5 mm ( 0

. 0 2 i n . ) s q u ar e w o v e n m e s h

.Attachment A Addendum To The 316(B) Evaluation Of The Harbor Generating Station

6 HGS currently has only one unit, Unit 5 operating, with once

- through cooling. Unit 5 operates off of waste heat from Units 1 and 2. Unit s 3 and 4 have been retired and Units 10

- 14 are simple cycle turbines with cooling towers. Designing Units 1, 2 and 10

- 14 without once

- through cooling may already result in a reduction in flow from a hypothetical baseline with all units opera ting as once

through that will meet the entrainment reduction standard. However, closed

- cycle cooling could provide an even greater reduction in entrainment than the current plant design. Mechanical or natural draft wet towers would require less modificat ion to the existing circulating water system piping and less real estate than dry cooling towers. The costs for construction of a wet mechanical cooling tower are about 60% less than the natural wet cooling tower. Natural wet cooling towers require less energy to operate and have lower annual costs than a wet mechanical draft tower. However, wet mechanical draft tower s generally have less aesthetic and air quality impacts than natural draft wet towers. The area surrounding HGS is heavily industrialized and would probably not be affected by compromised air quality

. T he site is , however , located near the city of Los Angeles. Since aesthetics and air quality issues would probably be greater for natural draft towers than for mechanical draft towers, wet mec hanical draft towers were chosen as the closed

- cycle cooling system option for preliminary evaluation.Attachment B Addendum To The 316(B) Evaluation Of The Harbor Generating Stati on

1 

## ATTACHMENT B - LADWP RESTORATION OP TIONS 1.0 INTRODUCTION In 2004, Alden Research Laboratory , Inc. (Alden) and the Electric Power Research 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 t m 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 part of that assessmen t, 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 e valuation, 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 eva luation 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;

 Contri bution to a restoration fund; and

 Water quality improvements. The two general requirements for the use of restoration are (1) a demonstration that the use of technologies and/or operational measures was evaluated, and the use of restoration measures is app ropriate because meeting the performance standards through implementation of technologies and/or operational measures is less feasible, less cost

- effective, or less environmentally desirable than meeting the performance standards in whole or in part throug h the use of restoration, and (2) a demonstration that the use of restoration will produce ecological benefits (production of fish and shellfish) at a level that is substantially similar to that which would be achieved through implementation of technologie s, 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 exa mples are summarized below.Attachment B Addendum To The 316(B) Evaluation Of The Harbor Generating Stati on

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), American shad (Susque hanna 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. Participa tion 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 Restoration Partnership. Dam Removal or Fishway Construction The U.S. Fish and Wildlife National Fish Passage Program is designed to restore native fish and other aquatic species to self

- sustaining levels by reconnecting habitat that has been fragmented by barriers, where such reconne ction would not result in a net negative ecological effect. Examples included installation of fishways (Delaware Bay), and a potential dam removal project (Rindge Dam, Malibu Creek). Alternative Restoration Projects Other potential restoration projects cou ld 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 coordination and agreements among a number of regulatory agencies and stakeholder groups. If LADWP decides to implement a project that it would fund and manage in cooperation with federal, state, and local resource agencies, the process could include the following at a minimum:

 Ident ify projects with involvement of resource agencies and stakeholder groups.

 Scale project to meet desired goals for offsetting losses attributable to impingement mortality and entrainment (IM&E).

 Develop implementation plan for restoration with input from r esource 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 Harbor Generating Stati on

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 ach ieved

.  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 implemen tation plan to develop requests for proposals for engineering and construction.

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

 Implement verification monitoring and schedule periodic updates on progress and continue r eviews 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 monito ring plan will supply the necessary information to ensure that the goals of the restoration are being achieved. Additional funding may be necessary to ensure that verification monitoring is adequate. An example of the successful implementation of this appr oach is the funding provided from the Moss Landing Power Plant (MLPP) to the Elkhorn Slough Foundation (ESF) for their programs related to the preservation and enhancement of the Elkhorn Slough National Estuarine Research Reserve (see attached). The succes s of this program has been widely recognized, and is largely due to the maturity of the management plan for the slough that was developed by the ESF. The ESF has been able to leverage the money provided by MLPP many times over to accomplish much more than could ever be achieved from a single restoration project. The successful implementation of this approach requires identifying an existing entity like the ESF that has a proven track record with implementing restoration programs. 

## 3.0 SPECIFIC RESTORATION PROJEC TS APPLICABLE TO HAR BOR GENERATING STATION The purpose of this section is to identify specific, local restoration projects that are potentially applicable to the HGS, and identify data necessary if each project were to be selected for implementation. Poten tial restoration projects should be considered based on their ability to offset entrainment and/or impingement at HGS

. Any specific conservation, enhancement, or restoration project that is to be used for this purpose should have a nexus (i.e., offset) to the 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 HGS (Los Angeles and Orange counties) ;
 Proj ects that enhance habitat through watershed management ; and

 Projects that enhance the nearshore coastal environment in the vicinity of HGS (Santa Monica Bay and San Pedro Bay)

. Projects that result in removal of accumulated sediment from coastal wetlands w ould increase the coastal salt marsh habitat, which would, in turn, increase their biological productivity. Projects that restore the tidal flow between the ocean and the wetlands to historic levels would have a similar e ffect on productivity. Other proj ects that involve watershed management could reduce wetlandAttachment B Addendum To The 316(B) Evaluation Of The Harbor Generating Stati on

4 sedimentation and thus preserve existing wetland habitat. Projects that enhance the biological productivity of Santa Monica and San Pedro bays could directly offset the loss of productivity in th e 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 projects 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 recovery plans as references, three major categories of projects have been identified that are appropriate for inclusion as restoration alternatives to offset IM&E losses. These projects have the potential to create, restore and preserve habitat equivalent to the amount of habitat that produced the estimated n umbers 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 potential population effects of IM&E on specific species and at the same time contribute to the overall health of nearshore/coastal habitats. 

### 3.1 C OASTAL 

### W ETLAND 

### P ROJECTS At one time , coastal lagoons, salt marshes, and other wetlands created by the merging of creeks and rivers with the Pacific Ocean characterized the shore line of Santa Monica Bay, Los Angeles and Long Beach Harbors, and shoreline areas further south. As these coastal areas became more densely populated and more highly developed, most of the marshes were filled and the creeks and rivers were channeled into c oncrete waterways to eliminate the periodic flooding that plagued these low

- lying areas. In recent years, public sentiment has turned to the task of preserving the remaining wetlands in this area and, where possible, to restoring those wetlands to a state that more closely resembles historic conditions. This category of projects includes actions taken directly within the boundaries of these wetlands to restore and/or enhance habitats that serve as spawning grounds for fish and other aquatic species. Projec ts 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 wet lands. 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 c o n s i d e r e d for evaluation include several within Santa M onica Bay , as well as projects in nearby Orange County. Project summaries are presented in order of coastwise location (upcoast to downcoast) 3.1.1 Zuma Wetlands Zuma Wetlands is a small, 6

- acre, freshwater marsh and creek situated about 38 miles upcoast of the HGS. The wetlands have historically served as a wildlife corridor and nesting site for a variety of birds and small mammals. By the early 1990s , periodic dumping of surplus construction and road building material had heavily impacted the wetlands and surro unding 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. Wet land 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 Harbor Generating Stati on

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 ater wetland/dune/riparian habitat. Restoration of this wetland is an ongoing process, which continues at this time. 3.1.2 Malibu Lagoon Located approximately 33 miles upcoast of the HGS, Malibu Lagoon is a coastal lagoon and salt marsh fed by Malibu Creek and i ts 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 seasonal rebuilding of the beach area dams the lagoon and c uts 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. Severa l habitat restoration or enhancement projects are in existence that affect the Malibu Creek and Lagoon directly, or indirectly, due to their influence on creeks that are tributaries of Malibu Creek. 3.1.3 Topanga Lagoon and Creek Historically , the Topanga Lagoon covered more than 30 acres, but has now been reduced to only 2 acres (mostly due to the deposition of 800,000 cubic feet of fill into the lagoon during the 1934 realignment of the Pacific Coast Highway). Located approximately 30 miles upcoast of the HGS, the lagoon is fed by Topanga Creek and its associated watershed. Over the years, development in the area has increased sedimentation rates, which constrain the channel and impede fish migration by species that include the endangered Steelhead trout. Upper Topanga Creek is listed on the State 303(d) list of impaired waterbodies. The Santa Monica Bay Restoration Commission, in conjunction with other agencies, has conducted a comprehensive Topanga Creek Watershed and Lagoon Restoration Feasibility Study to ide ntify ways to restore these resources. The California Department of Parks and Recreation recently purchased 1,659 acres of lower Topanga Canyon , including the current and historic lagoon sites. 3.1.4 Ballona Wetlands Located about 20 miles upcoast of the HGS, t he Ballona Wetlands contains saltwater marsh, freshwater marsh, coastal bluff, and dune habitats. The area, at one time, covered approximately 2,000 acres, but due to human encroachment and development , the wetland has been greatly reduced over the last 10 0 years. In recent years, about 340 acres of the wetland has been preserved due to the efforts of numerous organizations that are dedicated to the preservation and restoration of the wetland. These organizations include Friends of Ballona Wetlands, the Bal lona 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 th e only remaining large coastal wetland in Los Angeles County. 3.1.5 Los Cerritos Wetlands The Los Cerritos Wetlands is located about 12 miles downcoast of the HGS. The wetland straddles the Los Angeles

- Orange County border. It currently consists of about 130 wet land acres, with nearly 800 acres of degraded habitat proposed for restoration. Historically , it consisted of about 2,400 acres and included what is now Alamitos Bay. Since much of the site was modified due to former oil development activities, most of the land was privately held. In 2006, the California Coastal Conservancy was one of several agencies that purchased 66 acres of the wetlands, and hopes to acquire more. The Los Cerritos Wetlands Land Trust of Long Beach and Seal Beach is one organization comm itted 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 HGS makes it an attrac tive restoration option, other considerations associated with the project make it less than ideal. The recently submittedAttachment B Addendum To The 316(B) Evaluation Of The Harbor Generating Stati on

6 final report of the City of Long Beach, Los Cerritos Wetlands Study Group (available as a downloadable pdf file at http://www.longbeach.gov/plan/pb/cpd/los_cerritos.asp ) cited several pressing issues that need to be dealt with in order to proceed with any of the proposed restoration projects. Two of these issues are the numerous and varied zoning and jurisdictional concerns related t o t h e a r e a o f th e f

o rm e r w e t l a n d s , a n d th e a r e a ’ s h i s t o ry 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 s a l s i t e . These concerns are reflected in the ranking of this restoration option. 3.1.6 Bolsa Chica Lowl ands The Bolsa Chica Lowlands Restoration Project is located about 17 miles downcoast from the HGS adjacent to the City of Huntington Beach. The purpose of the project is to restore portions of the wetland ecosystem of the Bolsa Chica lowlands. The project area covers about 1,247 acres, and has restored tidal influence from the Pacific Ocean to about one

- half of this area to reinvigorate the wetland ecosystem. To achieve the biological benefits of tidal restoration, a direct connection to the Pacific Ocean was reestablished through the creation of a new tidal inlet that cut through Bolsa Chica State Beach and crossed the Pacific Coast Highway near the Huntington Mesa. Construction is currently underway and is anticipated to span a total of 2.5 to 3 years, in order to avoid or minimize impacts to fish and wildlife resources, coastal traffic, and beach recreation. 3.1.7 Huntington Beach Wetlands The Huntington Beach Wetlands are located about 23 miles downcoast from the HGS, adjacent to the Huntington Beach Generatin g Station. The total area of the wetlands is about 180 acres. Over the years, the wetlands have been divided into a number of smaller parcels by the development of the Huntington Beach area. The Huntington Beach Wetlands Conservancy plans to acquire the en tire 180 acres and restore it in accordance with a comprehensive wetlands restoration plan that they are currently preparing. Restoration will include the improvement or re

- establishment of tidal circulation within the wetlands. This will provide additiona l habitat for local fish and invertebrate species. In fall 2006, AES Huntington Beach was required to restore 66.8 acres of the Huntington Beach Wetlands to offset entrainment losses for Units 3 and 4. 3.1.8 Upper Newport Bay Ecological Reserve Newport Bay is lo cated approximately 27 miles downcoast from the HGS. The Upper Newport Bay Ecological Reserve was created in 1975 as result of the purchase of 527 acres of land in and around the bay from the Irvine Company and the transfer of 214 acres of tidal wetlands f rom the County of Orange to the s tate. An additional 11 acres of land in Big Canyon were 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 nu mber of restoration projects within Upper Newport Bay. The largest is the dredging of 2.1 million cubic yards of sediment. The project will restore and maintain tidal movement within much of the Bay. Much of the dredging project still needs funding, as wel l 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 ROJECTS Projects that control or reduce sediment transport into coastal wetlands may include er osion 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; restoratio n of floodplain habitat; and other Best Management Practices. The implementation of watershed management projects as part of the restoration plan is based on the nexus between the loss of wetland area and its associated reduction of biologically productiv e habitat with the infilling of the wetlands by sediments eroded from its watershed.Attachment B Addendum To The 316(B) Evaluation Of The Harbor Generating Stati on

7 3.2.1 Las Virgenes Creek Restoration Project Las Virgenes Creek is an important tributary of Malibu Creek and Lagoon. Las Virgenes joins Malibu Creek approximately 5.5 miles fr om 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 b e 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 have been proposed, or are underway, to eradicate non

- native/invasive plants from several of the creeks that feed the wetlands along the shore of Santa Monica Bay and areas to the south. Plants like the Giant Reed ( Arundo donax ) clog waterways, increase sedimentation, and consume large quantities of water. Removal of these plants can help restore flow within these coastal creeks and marshes to historic levels. Non

- native plant eradication programs are currently underway in lower Topanga Creek, Malibu Creek, and Solstice Creek (a tributary of Malibu Creek). 

### 3.4 N EARSHORE 

### C OASTAL 

### P ROJECTS Projects for enhanc ing nearshore coastal areas include restoring degraded habitat such as kelp beds and rocky intertidal areas, and projects that establish new habitat such as the construction of artificial reefs. The increased biological productivity resulting from these p rojects 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 fro m the Santa Monica Bay Restoration Commission (as part of the Santa Monica Bay Restoration Plan) for a project to identify the causes of degradation of the intertidal habitats in Santa Monica Bay. The project will identify, evaluate, and recommend practica l restoration techniques for these habitats. 3.4.2 Kelp Restoration Santa Monica Bay Keeper has an ongoing kelp bed restoration project that has been partially funded as part of the Santa Monica Bay Restoration Plan. Historically, the rocky northern (Malibu area ) and southern (Palos Verde peninsula only about 10 miles upcoast of the HGS) portions of the bay were once covered by dense kelp forests. Over the last 50 years the acreage of these beds has been greatly reduced. Several kelp restoration projects, includi ng 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

- rea red kelp plants into areas where kelp coverage has declined. Kelp beds provide habitat for numerous species of fish, invertebrates, and marine mammals. Increasing the size of the kelp beds in Santa Monica Bay or the Palos Verde peninsula to the west of HGS , and the associated increase in biomass that would accompany the restoration, could help offset IM&E losses due to operation of coastal generating stations. 3.4.3 Artificial Reef Several artificial reefs have been constructed along the coast of California, most notably the San Clemente Artificial Reef (SCAR) that was built as part of the mitigation for the San Onofre Nuclear Generating Station (SONGS) thermal discharge. SCAR was established in 1999 and its performance has been monitored since that time. The arti ficial reef modules have provided new substrate for giant kelp and other algae. The reef and its associated kelp canopy have, in turn, provided new habitat for fish and invertebrates. Because of the location of the HGS in the LA

- Long Beach Harbor Complex,Attachment B Addendum To The 316(B) Evaluation Of The Harbor Generating Stati on

8 an artificial reef in the immediate vicinity of the facility is not an option. Construction of an artificial ree f outside of the immediate area of HGS is, however, worthy of consideration. 3.4.4 Restocking of Affected Fish Species Hubbs

- Seaworld Research Institu te (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 spe cies, and is assessing the feasibility of breeding rockfish. The technology developed by the institute, as part of their Ocean Resources Enhancement Hatchery Program, could potentially be used to restock species, although the 316(b) regulations discourage a hatchery replacement approach. 

### 3.5 P RELIMINARY 

### R ANKING 

### /E VALUATION OF 

### R ESTORATION 

### P ROJECTS A set of selection criteria was developed for ranking the prospective habitat restoration projects previously described, or any other comparable projects that might be considered for implementation. They include:

 Location  Cost effectiveness

 Nexus to IM&E effects  Ability to measure performance

 Basic need or justification for project  Success of comparable restoration projects

 Nature and extent of ecological benefits  Ti me before benefits accrue

 Stakeholder acceptance  Technical feasibility

 Administrative considerations  Opportunities for leveraging of funds/Availability of matching funds

 Consistency with ongoing resource agency work and environmental planning  Legal hur dles (e.g., permits, legal access)

 Implementation costs  Duration of benefits Depending upon the nature of a particular project, the relative importance and weighing of these criteria may vary. As a general proposition, however, projects will be selecte d so as to maximize the offset of IM&E effects for compliance with 316(b), and secondarily to optimize ecological benefits to Santa Monica Bay/San Pedro Bay, or adjacent offshore areas within the Southern California Bight. This process will ensure that th e most effective projects are assigned the highest priority. A description of each of the criteria is provided below. Location Ideally , the location of the project is in the same source water/ receiving water bodies that are affected by the operation of t he facility. Scores decrease as the distance between the project area and those waterbodies increases. Projects that involve waterbodies and watershed areas that feed into the affected areas can have a high ranking , but are not ideal. N e x u s t o f

a c i l i t y ’ s IM&E effects A project that enhances or replaces the species affected by the facility, in the waterbodies affected by the facility would have the ideal nexus. As the project moves away from those species and locales, its ranking decreases. The nexus is the relationship between the environmental impacts resulting from the operation of the facility and the environmental benefits of the proposed project.Attachment B Addendum To The 316(B) Evaluation Of The Harbor Generating Stati on

9 Basic need or justification for project This category requires an evaluation of the need or justification f or 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 p roperty be razed to accommodate the project, it may require considerably more justification. Other projects, like the establishment of artificial reefs where none formerly existed, may be worthwhile , but will require some justification for their adoption ( lowered score). Technical feasibility Is the technology or methodology utilized by the proposed project proven and effective? Has it, or something similar, been used under similar conditions? Proven track record, or pie in the sky? Stakeholder acceptance I s the proposed project likely to have the support and approval of the regulatory agencies involved, the owners and operators of the facility, and the local citizenry? Nature and extent of ecological benefits This is a category of magnitude. Does the proje ct have a relatively narrow and limited ecological benefit, such as increasing the population of a single species within a limited spatial context, or does it benefit a large number of species (directly and indirectly) over an extensive area (higher rankin g) ? 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 cate gory. 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 bene fits) category. Duration of benefits Projects with environmental benefits that continue over a long period of time will receive a higher ranking than those with short

- term, transient, benefits. This category works in conjunction with the two previous cate gories. 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 y o n d f e a s i b i l i t y t o the question of the success or failure of comparable projects. High rankings are given to projects th at 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). Consistency with ongoing resource a gency work and environmental planning Does the proposed project conflict with any ongoing resource agency work or environmental planning? Projects without conflicts, that mesh well with ongoing projects and policy, will receive the highest rankings. Projec ts that are inconsistent with current environment policy and ongoing projects 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 h u

r d l e s ” )

.Attachment B Addendum To The 316(B) Evaluation Of The Harbor Generating Stati on

10 Legal hurdles (permitting, etc.) In this category, projects that face signi ficant legal hurdles, such as those that require extensive permitting for their implementation, will receive lower ranking than those projects not hindered by such requirements. The cost of overcoming these hurdles (time and money) should also be incorpora 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 ” )

. P r o v i d i n g a d d i t i o n a l f u n d i n g for an ongoing project that has already passed these hurdles, wou ld also receive a high ranking. Implementation costs This category is fairly straightforward , but requires some additional information about the magnitude of the IM&E impacts to be offset for a proper evaluation of any potential project. The environmental benefits accrued by a given project need to be weighed against the impacts that need to be offset ( “ C o s t / B e n e f

i t ” )

. Funding opportunities (matching funds, leveraging of funds, etc.) Ongoing projects will do well in this category since they are already re ceiving at least some funding. Many potential restoration projects have popular support , which can help with additional funding as w e l l a s l e n d i n g s up p o rt i n c a t e g 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 egal hurdles

. ” 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 u n d i n g opportunities and would rank lower. Ability to measure performance Can the beneficial environmental effects of the proposed project be measured in some fashion that relates to offsettin g the impacts of the operation of the facility in question? Projects with more qualitative, less tangible benefits would score lower in this ranking. Certain projects lend themselves more easily to this category than others. The restocking of an area with fish can readily be assessed by noting the number of fish introduced, the number surviving, the number reproducing, etc. Artificial reefs and restored kelp beds can be surveyed to record species recruitment and the associated increase in biomass. Restored wetlands may be more difficult to assess because of their complexity, including terrestrial and aquatic habitats, nursery areas, birds, mammals, fish, and invertebrates, transient species, etc. The performance of projects that restore watershed areas is ev en more difficult to assess because of the indirect nature of many of their benefits to the areas directly impacted by IM&E losses. Cost / Benefit How much bang

- for

- the

- buck can be hard to gauge for many projects. The cost may be relatively easy to calcula te, 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 g o r y m a y b e s o m e w h a t subjective with both the cost and benefits of a project placed somewhere along a gradient that ranges from small to large. Administrative considerations How large are the administrative needs of a potential project. This includes taking the project through any required approval/permitting process, implementing the project, and administering it through to completion. Projects with limited need for oversight would score higher than projects requiring a large administrative infrastructure.Attachment B Addendum To The 316(B) Evaluation Of The Harbor Generating Stati on

11 Using a five point ranking system, each of the projects described in Section 3 was scored fo r 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 HGS, would be ranked 5 for its Location, but if it faced significant issues concerning regulatory permitting for the project, it might rank a 2 for Legal Hurdles. Rankings for the individual projects are shown in Table B

- 1. No rankings are provided for Implementation Costs or Cost Effectiveness at this time, since the mag nitude 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 tu n i t i e s f

o r l e v e r a g i n g o f f u n 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

u n 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 costs to be shared among the power generating facilities located on the coast in Santa Monica Bay or in the larger Los Angeles Basin coastal area. This would increase the scores for wetland projects in Orange County area that are closer to the power gen erating 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 artifici al reef projects would be the most suitable for further evaluation. The projects with the highest ranking were the Ballona Wetlands, upper Newport Bay, the Bolsa Chica Lowlands, and the Huntington Beach Wetlands projects. Located about 20 miles upcoast fr om HGS, the Ballona Wetlands project also scored highly because it is located only 4 miles upcoast of another LADWP power plant, SGS, and is the only remaining large coastal wetland in Los Angeles County. In contrast, the Los Cerritos Wetlands, located onl y 12 miles downcoast of the HGS, 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 wi th one of the open coastal projects such as the establishment of an artificial reef to provide restoration credits for both estuarine and coastal species.Attachment B Addendum To The 316(B) Evaluation Of The Harbor Generating Station

12 T ABLE B - 1. Q UALITATIVE RANKING , WITH 1 BEING LOWEST AND 5 BEING HIGHEST , OF POTENTIAL RESTOR ATION PROJECTS FOR OFFSET TING H ARBOR G ENERATING S TATION IM&E LOSSES .

RESTORATION PROJECT ZUMA WETLANDS MALIBU

LAGOON TOPANGA

LAGOON AND CREEK BALLONA

WETLANDS LOS

CERRITOS WETLANDS BOLSA CHICA

LOWLANDS HUNTINGTON

BEACH WETLANDS UPPER

NEWPORT BAY LAS

VIRGENES CREEK NON-NATIVE

PLANT ERADICATION SANTA MONICA

BAY ROCKY INTERTIDAL SANTA MONICA

BAY KELP BEDS ARTIFICIAL REEF EVALUATION CRITERIA Location 3 3 3 3 4 4 4 3 2 2 3 3 3 Nexus to HGS Impacts 3 3 3 4 4 4 4 4 3 3 3 3 3 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 47 50 48 59 55 57 57 58 45 45 41 52 53Attachment B Addendum To The 316(B) Evaluation Of The H arbor Generating Station

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 determin e 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, Bolsa Chica Lowlands and Huntington Beach Wetlands received the hi ghest rankings using the criteria previously described. Although located almost 20 miles upcoast of HGS, the Ballona Wetlands scored highly because they are located only 4 miles upcoast from another LADWP facility, SGS, and they are the only remaining larg e 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 entra inment losses from the power plant. The proposed restoration of the Los Cerritos Wetlands, 12 miles downcoast of the HGS , 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 t he 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 issu es that need to be dealt with prior to proceeding with any of the proposed restoration projects. These issues include the numerous and varied zoning and jurisdictional concerns related to th e a r e a o f th e f

o r m e r w e t l a

n d s , 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 hazardous waste disposal site. These concerns were reflected in the lower ranking of this restoration option in comparison with the Ballona Wetlands. A major wetlands restoration project at a location like the Ballona Wetlands could be supplemented with a coastal project to compensate for losses to marine coastal fishes. The projects that received the highest ranking using the criteria in this report were kelp ked restoration and artificial reefs. The SONGS is using an artificial reef as mitigation for the effects of the thermal discharge on kelp beds and associated communities. Studies at a pilot

- scale artificial reef being used in the design of the final full

- scale project show that the artificial reef is performing similar to natural reefs in the area. De velopment of giant kelp (Macrocystis spp.) on an artificial reef would provide the added benefit of increasing the area of kelp habitat, an important habitat

- forming community in the nearshore areas at the north and south headlands of Santa Monica Bay. Kel p beds provide habitat for a wide variety of invertebrates and fishes. An artificial reef project in Santa Monica Bay benefits from all of the work that has been completed for the SONGS reef project. It is also relatively easy to demonstrate the benefits from an artificial reef, since the SONGS project has shown that communities develop fairly rapidly on the new habitat.Attachment C Addendum To The 316(B) Evaluation Of The H arbor Generating Station

1 

## ATTACHMENT C - VELOCITY CALCULATIONS The following is a summary of HGS velocity calculations. DATA: 

### Flow (Q): 167 cfs Water Elevation: El. 0.0 ft Trash Rack Width: 56 ft Trash Rack Invert: El.

- 21.5 ft Top of Trash Rack: El.

- 11.0 ft Intake Pipe Internal Diameter: 8.0 ft Intake Pipe Area: 50.2 ft 2 

### Number of Intake Pipes: 2 Number of Bays: 4 Screen Width: 6.2 ft Screenhouse Invert: El.

- 16.0 ft
FORMULA USED:


### ) ( ) ( ) ( area

A flow Q velocity V  CALCULATIONS:



### sec / 3

. 0 ) 5

. 21 5

. 11 ( * 56 167 ) ( ft ft ft cfs trashrack V  
 

sec / 7

. 1 2

. 50 * 2 167 ) ( 2 

### ft

ft cfs s Intakepipe V 





### sec / 8

. 0 ) 0

. 16 0

. 0 ( * 2

. 6 * 2 167 ) 2 ( ft ft ft ft cfs screens V   

sec / 4

. 0 ) 0

. 16 0

. 0 ( * 2

. 6 * 4 167 ) 4 ( ft ft ft ft cfs screens V   Attachment D Addendum To The 316(B) Evaluation Of The Harbor Generating Station

1 

## ATTACHMENT D - FISH MORPH O METRY AND SCREEN MES H HEADLOSS The following information on fish morphom etry 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 5

. This study was designed to use physical measurements from preserved ichthyoplankton to compute the expected size of larval f ish 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 greatest cross

- sectional dimension (such as skull width or other measures of body girth) to overall fish length. Then, the greatest mesh dimension is computed, typically the mesh diagonal. Smith et al. (1968) found that the maximum cross - sectional diameter of the organism must be greater than the mesh diagonal if it is to be fully retained. For a given cross

- sectional diameter and associated standard deviation, the percentage retained and excluded is calculated by integration under a normal curve. Examples of this type of analysis may be seen in Vannucci (1968), Lenarz (1972), Colton et al. (1980), Turnpenny (1981), Schneeberger and Jude (1981) among others. Results of this analysis may then be used to develop working guidelines for the minimum size necessary for retention of each s pecies

... . ” 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 e ffect of length/head capsule depth ( HCD ) on entrainment and impingement. The reported HCD at body length wa s used to predict the HCD for H GS 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.

5 Public Service Enterprise Group. (2002). Salem Generating Station, N JPDES 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 Harbor Generating Station

2 Atlantic Silverside

Eggs: Probability Probability Entrainment Impingement 0.00000000 1.00000000 Larvae length ln(le ngth) 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 0.25 179435 5 1.6094379
- 0.54201 0.581576 0.08860428 0.91139572 6 1.7917595
- 0.35732 0.699547 0.00135686 0.99864314 7 1.9459101
- 0.20117 0.817775 5.5983E
- 06 0.9999944 8 2.0794415
- 0.0659 0.936224 1.0692E
- 08 0.99999999 9 2.1972246 0.053413 1.054866 1.3169E
- 11 1 10 2.3025851 0.160144 1.17368 1.2815E
- 14 1 11 2.3978953 0.256693 1.292648 1.1191E
- 17 1Attachment D Addendum To The 316(B) Evaluation Of The Harbor 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 Harbor Generating Station

4 Bay anchovy

Eggs: Probability Probability Entrainment Impingement 0.00007334 0.99992666 Larvae length ln(length) ln(HCD) HCD Probability Probability (mm) (mm) Entrainment Impingement

1 0
- 1.69755 0.183132 1 3.5926E
- 10 2 0.6931472
- 1.2165 0.296265 0.99933809 0.00066191 3 1.0986123
- 0.93511 0.392543 0.9311524 0.0688476 4 1.3862944
- 0.73546 0.479286 0.60240373 0.39759627 5 1.6094379
- 0.5806 0.559565 0.24494069 0.75505931 6 1.7917595
- 0.45 406 0.635041 0.07122037 0.92877963 7 1.9459101
- 0.34708 0.706746 0.01687337 0.98312663 8 2.0794415
- 0.25441 0.775371 0.00355533 0.99644467 9 2.1972246
- 0.17267 0.841413 0.00070377 0.99929623 10 2.3025851
- 0.09955 0.905243 0.00013543 0.99986457 11 2.39 78953
- 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 Harbor Generating Station

5 Atlantic menhaden

Eggs: Probability Probability Entrainment Impingement 0.00000000 1.00000000 Larv ae length ln(length) ln(HCD) HCD Probability Probability (mm) (mm) Entrainment Impingement

1 0
- 0.46918 0.625518 0.03208407 0.96791593 2 0.6931472
- 0.18776 0.828816 1.4783E
- 05 0.99998522 3 1.0986123
- 0.02314 0.977127 1.5362E
- 08 0. 99999998 4 1.3862944 0.093661 1.098187 3.9487E
- 11 1 5 1.6094379 0.184257 1.202325 2.0644E
- 13 1 6 1.7917595 0.258279 1.2947 1.8748E
- 15 1 7 1.9459101 0.320865 1.378319 2.6405E
- 17 1Attachment D Addendum To The 316(B) Evaluation Of The Harbor Generating Station

6 Naked goby

Eggs: Probability Probability Entrainm ent 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 0.089824 4 3 1.0986123
- 0.48365 0.616528 0.01626992 0.98373008 4 1.3862944
- 0.24171 0.785284 2.0475E
- 06 0.99999795 5 1.6094379
- 0.05405 0.947388 3.4819E
- 11 1 6 1.7917595 0.099286 1.104382 3.0815E
- 16 1 7 1.9459101 0.228926 1.25725 2.5064E
- 21 1Attachment D Addendum To The 316(B) Evaluation Of The Harbor Generating Station

7 Wire - mesh screen head loss characteristics

Assumptions for head loss calculations: Screen approach velocity at 1 feet/sec Through
- flow screen (two screen mesh baskets in flow path) Head loss coefficients from M. Papworth 1972 Screen characteristics:

Scree n 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% 18 mesh 0.056 0.017 0.43 1. 0 48% yes 39% 30 mesh 0.033 0.012 0.30 0.5 41% yes 33% 50 mesh 0.020 0.009 0.23 0.3 30% yes 24% 70 mesh 0.014 0.0065 0.17 0.2 30% yes 24%Attachment D Addendum To The 316(B) Evaluation Of The Harbor Generating Station

8 LITERATURE CITED Colton, J.B., Jr., J.R. Green, R.R. Byron, and J.L. Frisella. 1980. Bongo net retention rates a s effected by towing speed and mesh size. Can. J. Fish. Aquat. Sci. 37:606

- 623. Lenarz, W.H. 1972. Mesh retention of Sardinops caerulea and Engraulis mordax by plankton nets. Fish. Bull. U.S. 70:839

- 848. Schneeberger, P.J. and D. J. Jude. 1981. Use of fish larva morphometry to predict exclusion capabilities of small

- mesh screens at cooling

- water intakes. Trans. Amer. Fish. Soc. 110:246

- 252. Smith, P.E., R.C. Counts, and R.I. Clutter. 1968. Changes in filtering efficiency of plankton nets due to clogging und er tow. J. Cons. perm. int. Explor. Mer.32: 232

- 248. Turnpenny, A.W.H. 1981. An analysis of mesh sizes required for screening fishes at water intakes. Estuaries, 4(4):363

- 368. Vannucci, M. 1968. Loss of organisms through the meshes. In D.J. Tranter (ed.), Part I, Review on zooplankton sampling methods, p. 77

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

9 

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

- mesh traveling water screens with fish protection or MIS modules would have to be conveyed back to the harbor. To prevent re

- impingement , the return line will have t o tr a n s p o r

t f i s h a n d d e b r i s t o t

h e L

. A

. H a

r b o r ’ s W e s t B a s i n v i a a 1, 4 00

- f oo t

- long return pipe . This return location was selecte d 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 parallel the existing warm water return line

. Addi tional w ater would need to be added to the return line to provide the fish removed from the screens a 6 in ch water cushion. A pipe was selected as the area surrounding HGS is heavily industrialized and the pipe would most likely have to be buried

. Clea ning of the trough both near the screens and within the tidal area would be fairly easy and could be conducted by plant personal using either brushes or a high

- pressure spray. 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 T he existing discharge lines would need to be tapped. A pump would be required to transport water to the return line

. Twice as much pipe with isolation valves.

Construction Impacts on Plant Operation Would require a unit to be shutdown while the discharge i s tapped. Could be completed during a scheduled outage. None.

Impacts on Plant Operation Heat treatments would need to be timed to coincide when units are operating at maximum inlet temperature and plant output. None.

Impacts on Screen Operation None. N one. Impacts on Survival No survival during heat treatment. None. Reliability If return pipe or hot water line fails there is no redundancy. If one return pipe fails , the second one can be brought into operation rapidly. Installation Cost 1 $2 78 ,000 $33 7,000 O&M Costs 1 $18,000 $19,000 1. Costs are in 2006 and are based on the same assumptions as the costs in the cost section of this Addendum The same methods used to clean the fish return for the modified traveling screen options would be applicable to th e fish return required for Modular Included Screens. The fish return pipe for the MIS would be the same length as the traveling screen return but would require a larger piper, to accommodate the required bypass flow. The preceding table is valid for MIS return, except for the costs. For the MIS return system the cost for both cleaning options would be very similar but higher than those in the table.