F I N A L R E P O R T 

ADDENDUM TO

EVALUATION OF THE HAYNES 

GENERATING STATION WITH RESPECT TO 

THE CLEAN WATER ACT

SECTION 316(b) REQUIREMENTS 

PROVIDING A CURRENT ASSESSMENT OF 

ALTERNATIVE TECHNOLOGIES AND 

OPERATIONAL MEASURES

Prepared by 

Alden Research Laboratory, Inc. 

EPRI 

MBC Applied Environmental Sciences 

Tenera Environmental, Inc. 

URS Corporation 

for 

City of Los Angeles Department of Water and Power 

111 N. Hope Street 

Los Angeles, California 90012-2607

April 6, 2007 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

i

TABLE OF CONTENTS 

SECTION PAGE

1.0 INTRODUCTION.................................................................................................... 1-1

2.0 ADDITIONAL INFORMATION CURRENTLY AVAILABLE........................ 2-1

2.1 HNGS RE-POWERING PROJECT .................................................................................2-1

2.2 ADDITIONAL TECHNOLOGIES....................................................................................2-1

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

2.4 COSTS 2-2

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

3.0 ENTRAINMENT REDUCTION OPTIONS......................................................... 3-1

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

3.2 MODULAR INCLINED SCREENS..................................................................................3-3

3.3 FLOW REDUCTION .....................................................................................................3-3

3.4 CLOSED-CYCLE COOLING..........................................................................................3-4

3.5 ADDITIONAL TECHNOLOGIES....................................................................................3-5

4.0 IMPINGEMENT MORTALITY REDUCTION OPTIONS............................... 4-1

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

4.2 MODULAR INCLINED SCREENS..................................................................................4-1

4.3 FLOW REDUCTION .....................................................................................................4-2

4.4 CLOSED-CYCLE COOLING ..........................................................................................4-2

4.5 ADDITIONAL TECHNOLOGIES....................................................................................4-2

5.0 COST UPDATE ....................................................................................................... 5-1

6.0 DATA GAPS AND UNCERTAINTIES................................................................. 6-1

7.0 CONCLUSIONS ...................................................................................................... 7-1

LIST OF ATTACHMENTS

ATTACHMENT A - SUMMARY OF 2004 EVALUATION OF HNGS

ATTACHMENT B - LADWP RESTORATION OPTIONS

ATTACHMENT C - FLOW CALCULATIONS 

ATTACHMENT D - FISH MORPHPMETRY AND SCREEN MESH HEADLOSS 

ATTACHMENT E - POTENTIAL FISH RETURN CLEANING SYSTEMS 

ATTACHMENT F - NARROW-SLOT, WEDGEWIRE SCREEN CONCEPTUAL DESIGN 

LIST OF TABLES

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

TABLE 2-2. REVISED TABLE 2-3 FROM THE INITIAL EVALUATION – COMPARISON OF PERCENT 

COMPOSITION OF ENTRAINED LARVAE LENGTHS COLLECTED AT HNGS...................................2-8 

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

TABLE 3-1 FROM THE INITIAL EVALUATION)...............................................................................2-9 

TABLE 5-1. ALDEN’S APPRAISAL LEVEL COSTS OF EVALUATED ALTERNATIVES.............................5-2 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

1-1

1.0 INTRODUCTION 

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

Research Institute (EPRI), developed a report entitled “Evaluation of the Haynes Generating Station 

with respect to the Environmental Protection Agency’s 316(b) Rules for Existing Facilities” for the 

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

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

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

appropriate for the Haynes Generating Station (HnGS). A summary of the results of the 2004 

evaluation is provided in Attachment A. 

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

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

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

alternatives. This distinction will be maintained in this report. 

The technologies evaluated in the initial 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, diversion systems and 

behavioral barriers were eliminated from consideration to meet the entrainment reduction standard. 

Three technologies (i.e., cylindrical wedgewire screens, fine-mesh traveling screens, and modular 

inclined screens) were considered as entrainment and entrainment/impingement reducing options at 

HnGS. The Cooling Water Intake System (CWIS) location and hydraulic conditions at HnGS make 

this site unsuitable for wedgewire screens to be installed in the conventional manner (i.e., upstream of 

the CWIS at the bar racks and the use of air-burst backwash in the marina). 

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

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

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

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

Environmental (MBC), Tenera Environmental, Inc. (Tenera), and URS Corporation (URS). 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

2-1

2.0 ADDITIONAL INFORMATION CURRENTLY AVAILABLE 

The following new information has been assessed as it relates to Alden’s original evaluation: 

• HnGS has completed a re-powering project since the 2004 report; 

• Additional technologies have become available; 

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

• Costs can be updated to 2006 values; and 

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

Phase II Rule. 

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

flow as a result of the replacement of Units 3 and 4 with Unit 8 during re-powering. Also, velocity 

calculations are provided in Attachment C. 

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

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

2.1 HNGS RE-POWERING PROJECT 

Units 3 and 4 have been replaced by Units 8, 9, and 10 and are described as a 2+1 combined cycle unit 

(Unit 8). However, the new unit utilizes the existing intakes for the retired units. The original pumps 

have been replaced with lower flow capacity pumps. Each of the new pumps provides 40,000 gallons per 

minute (gpm), as opposed to the original 48,000 gpm. This flow reduction results in approximately a 5% 

lower flow than prior to re-powering and slightly lower velocities within the CWIS. The flow reduction 

can be used to take credit toward meeting the IM&E reduction performance standards under the 

calculation baseline. However, the credit does not change any of Alden’s original technology 

assessments. 

2.2 ADDITIONAL TECHNOLOGIES

In the 2004 report, there were four technologies characterized as “emerging technologies”: 

• Beaudrey’s Fish Protection System (FPS); 

• Filtrex Filter Candles; 

• Debris and Organism Collector (DOC); and 

• Geiger’s Multi-Disc Screening System. 

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

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

system that utilizes circular rotating screens with a fish “scoop” has been installed at one facility and is 

currently being tested. Therefore, there is no new information to assess the feasibility, cost, or 

effectiveness of these three technologies at this time. 

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

facilities. The first installation was at the Potomac Generating Station and was the subject of a one-year 

EPRI study. The preliminary results have been positive and it appears this technology has the potential to 

match the impingement mortality reduction results from Ristroph screens. In addition, this technology 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

2-2

provides the benefit of eliminating carryover. The second installation was in late 2006 at the Salem 

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

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

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

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

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

information on biological efficacy and operational issues. Because of the material used and way that the 

screen is constructed, the smallest mesh size available at this time is 1.75 millimeters (mm). Thus, this 

technology has the same “limitation” as the Modular Inclined Screen (MIS) system in excluding only 

larger entrained organisms, and therefore, would not meet entrainment performance standards for HnGS. 

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

considered in the same category as Ristroph screens. Both of these systems function on the “trap and 

transfer” 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. 

2.3 IMPINGEMENT MORTALITY AND ENTRAINMENT CHARACTERIZATION

Although the relative contribution of the most abundant species impinged has varied from 1978/1979 to 

2001/2002 to 2006, prominent species impinged include queenfish, topsmelt, northern anchovy, shiner 

perch, white croaker, and specklefin midshipman. This most current impingement data do not change 

Alden’s selection of appropriate technologies for consideration at HnGS. 

As expected, the entrainment data showed similar results. Gobies, blennies, silversides, white croaker, 

and northern anchovy are key species entrained. In 2006, silversides and jacksmelt were also relatively 

abundant. Of most interest were the results of the entrainment life history characterization. The 2006 

results confirmed the 1978/1979 results and documented that 92-100% (depending on species) of 

entrained organisms were “pre-transformation” stage. That is, the vast majority of entrained fish were 

less than 15 mm in length. The lengths of larvae collected in 2006 are provided in Table 2-2. This table 

replaces Table 2-8 in the initial evaluation. 

These results do not alter Alden’s selection of appropriate technologies for consideration in reducing 

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

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

2.4 COSTS

Alden has revised and included in Section 5 of this Addendum Table 5-1 (i.e., Table 6-3 from 2004 

report) to reflect current (2006) costs of appropriate technologies. An adjustment factor of 1.121 was used 

to account for inflation and the price per megawatt hour (MWh) was increased from $40/MWh to 

$50/MWh2. For technologies that were evaluated further in this Addendum, the costs presented in Table 

5-1 have been modified to reflect the updated evaluations. 

 

1

 Based on consumer price index from 2002 through 2006. 

2

 Based on average annual day ahead prices for 2006 using SP-15 CAISO real time data. 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

2-3

2.5 SECOND CIRCUIT COURT DECISION

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

impacts on the compliance alternatives and options discussed in the 2004 Report. The major components 

of the Decision are: 

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

are unlawful and cannot be used for compliance; 

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

Best Technology Available (BTA); and 

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

Plan due to EPA’s failure to provide adequate opportunity for public review and comment for 

these two provisions. 

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

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

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

The Court said EPA could consider three factors in this evaluation. The first is cost, but only in a limited 

manner. To reject closed-cycle cooling from a cost standpoint, EPA must determine that the industry 

cannot reasonably bear the cost of a national retrofit with these technologies. The two other factors EPA 

may consider are adverse environmental impacts associated with closed-cycle cooling and impacts to 

energy production and efficiency. 

A second major component of the Decision is a requirement to use the “best performing” technology. 

The Court determined that if EPA chose to use performance standard ranges, a facility’s decision could 

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

technology in the appropriate performance standard range must be used. The Court did say that a less 

costly technology than the “best performing” technology could be used if it works as least as well as the 

low end of the performance range of the “best performer.” 

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

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

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

provisions in the revised Rule. 

As a result of the Decision, it will be important for LADWP to consider technologies from several 

perspectives: 

• EPA could identify closed-cycle cooling as BTA: If this were to occur, it would be considered to 

be the “best performing” technology. Assuming this were the case, it is worth noting that EPA, in 

the Rule, stated that closed-cycle cooling was capable of achieving a 70 to 96% reduction in flow 

in salt water when make-up and blowdown flows are minimized. The lower end of the range was 

driven by states where water quality standards limited chloride to a maximum of 10% over 

background and therefore required a 1.1 cycle-of-concentration. It will be important to determine 

the level of flow reduction achievable in California. Whatever level of flow reduction could be 

achieved at HnGS with closed-cycle cooling would establish the performance standard. For 

example, it could be determined that salt water cooling towers at HnGS could achieve a 90% flow 

reduction (i.e. entrainment reduction). If this were the case, then a 90% reduction would become 

the HnGS performance standard. Alternative fish protection technologies and/or operational 

measures could be employed; as long as they achieved the same 90% reduction as closed-cycle 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

2-4

cooling. Closed-cycle cooling is discussed qualitatively in Sections 2.4 and 3.4 of this 

Addendum. 

• EPA could determine that closed-cycle cooling is not BTA or does not pass a re-proposed CostCost Test: In either case, the new driver for technology selection will be based on a 

determination of which technology is “best performing.” 

• EPA could revise the schedule: If EPA engages in a rulemaking, it is anticipated that the January, 

2008 deadline for submittal of the Comprehensive Demonstration Study (CDS) will be 

suspended. EPA did not budget for a major 316(b) rulemaking in 2007, so it is not clear when a 

revised Phase II Rule would become effective. The result is uncertainty as to when compliance 

will be required. Due to this uncertainty, EPA may revert to issuing §316(b) requirements on 

“Best Professional Judgement” (BPJ). This was the approach EPA used prior to promulgation of 

the Phase II Rule. Given California’s advocacy on 316(b) issues, this potential has little effect on 

LADWP’s facilities. The suspension of the schedule would allow additional time to conduct pilot 

studies to identify the “best performing” technology for HnGS. 

Another regulatory uncertainty for the Rule is anticipated guidance on whether or not the Rule is based on 

design or actual flow. This guidance has been promised for several years, but has yet to be provided. The 

flow is an important consideration for Units 1 and 2, which operate less frequently than the other units. 

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

• The technology has proven biological effectiveness; 

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

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

evaluated. 

Table 2-3 is a revision to Table 3-1 from the initial evaluation. 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

2-5

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

Location 

Long Beach, California (HnGS) 

Latitude: N 33o 45’ 05’’ 

Longitude: W118o 06’ 15’’ 

Waterbody: Pacific Ocean

NPDES permit expiration date: May 10, 2005 

Estimated project intake flow 

Plant design: 1,497 cfs (672,000 gpm) 

Units 1&2: 213.8 cfs (96,000 gpm) each 

Units 5,6&8: 356.5 cfs (160,000 gpm) each 

Intake velocities (mean lower low water) 

Horizontal current at trash rack: 1.4 feet/sec 

Intake conduit design velocity: 5.2 feet/sec 

Intake conduit calculated velocity: 5.0 feet/sec 

Intake channel velocity: 1.3 feet/sec 

Mean velocities upstream of screens: 

 Units 1&2 (stationary screens): 0.9 feet/sec 

 Units 5&6 ( traveling screens): 0.7 feet/sec 

 Unit 8 (traveling screens): 0.6 feet/sec 

Water Level 

Elevations 

Extreme low: El. -6.0 feet 

Mean lower low water: El. -2.7 feet 

Extreme high: El. 3.0 feet 

Water depths: (around intake) 

Maximum: approx 12.0 feet 

Minimum: approx 9.5 

Normal: approx 10.0 feet 

Other info: all elevations refer to mean sea level 

Project Structures 

Intake structure: 

Type: onshore intake 

Location: Long Beach Marina 

Intake openings: 7 

Top of intake opening: El. -2.0 feet 

Bottom of intake opening: El. -9.5 feet 

Intake opening width: 50 feet 

Intake barrier: bars centered 6 in apart 

Conduit pipes: 7 

Conduit pipe length: approx. 1,100 feet 

Conduit pipe diameter: 8 feet (inside diameter) 

Conduit pipe invert: El. -14.4 feet 

Intake channel structure 

Channel invert: El. -19.0 feet 

Banks: El. 8.0 feet 

Length: approx. 1.5 mi 

Design velocity: 1.0 feet/sec 

Calculated velocity: 1.3 feet/sec (mean lower low water) 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

2-6

Stationary Screens (Units 1&2) 

Location: along intake channel 

Sections: 4 (2 per unit, 10.0 feet wide, 21.7 feet tall) 

Invert: El. -15.0 feet 

Top: El. 6.7 feet 

Mesh size: 3/8 in 

Traveling water screens (Units 5, 6 & 8) 

Location: along intake channel 

Number: 12 (4 per unit) 

Unit 8: 

Screen width: 10.9 feet 

Invert: El. -16.0 feet 

Top: El 6.7 feet 

Rotation speeds: 1.4 rpm 

Units 5&6: 

Screen width: 9.0 feet 

Invert: El. -17.0 feet 

Top: El 6.7 feet 

Rotation speeds: 1.54 rpm 

Mesh size: 3/8in 

Spray wash volume per screen: 400 gpm 

Spray wash Operation: once per shift 

Trough configuration: two troughs leading to trash boxes 

Circulating water pumps 

Number of pumps: 12 (2 per intake) 

Type of pumps: vertical, single-staged 

Inlet elevation: -16.0 feet 

Flow per pump: 

Units 1-2: 107 cfs (48,000 gpm) 

Units 5 & 6: 178.2 cfs (80,000 gpm) 

Unit 8: 89.1 cfs (40,000 gpm) 

Total flow 

Condensers: 1497 cfs (672,000 gpm) 

Cooling water discharge 

Location: San Gabriel River 

Depth: 21.3 feet 

Discharge pipe: 6 conduit pipes 

Type: 3 discharge structures (one for each Unit pair) 

Power Generation 

Fuel Type: 

Units 1,2, 5, 6 & 8: gas/oil 

Plant output: (rated) 

Units 1&2: 222 megawatts (MW) (each) 

Unit 5: 341 MW 

Unit 6: 259 MW 

Unit 8: 235 MW 

Units 9&10: 170 MW (each) 

Total rated capacity: 1,619 MW 

Plant capacity factor (2000-2004) (No generation data for Unit 8 provided) 

Unit 1: 30% 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

2-7

Unit 2: 34% 

Unit 5: 26% 

Unit 6: 17% 

Average annual energy: 2,414,940 MWh (2000-2004)(Units 1, 2, 5 and 6) 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

2-8

TABLE 2-2. REVISED TABLE 2-3 FROM THE INITIAL EVALUATION – COMPARISON OF PERCENT 

COMPOSITION OF ENTRAINED LARVAE LENGTHS COLLECTED AT HNGS

 Percent Composition* 

Species 

2006 Study 

% of Total 

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

anchovy <1% 19% / 86% 28% / 12% 33% / 1% 20% / -- 

gobies 50% 86% / 97% 7% / 2% 7% / 1% <1% / -- 

blenny 19% 100 %/ 100% <1% / <1% -- / -- -- / -- 

white 

croaker 

2% 97% / 40% 2% / 60% 1 / -- -- / -- 

queenfish <1% 89% / 38% 11% / 62% -- /-- -- / -- 

References: Intersea Research Corporation (IRG), Haynes Generating Station Cooling Water Intake Study 

316(b) Demonstration Program 1978-1979. (1981) Tenera Environmental, IM&E Characterization 

Study Preliminary Results 2006, unpublished. (2007) 

*

1981 data / 2006 data
An Addendum To The 316(B) Evaluation Of The Hay

2-9

TABLE 2-3. INITIAL 

SCREENING OF 

FISH 

PROTECTION 

ALTERNATIVES AT 

H

NGS (REVISED 

TABLE 3-1 FROM THE IN

Concept 

Biological 

Effectiveness 

Proven 

Engineering 

Alternative 

Available 

Advantages 

over Other 

Concepts 

Potential for 

Application 

at H

NGS 

Com

Behavioral Barriers Sound yes yes no no The focus of recent fish 

involving underwater sobeen on the use of new frequency acoustic systpreviously been availabSound devices are not aentrainment reduction ahave not yet developed have insufficient swimmentrainment. 

Infrasound no yes yes no There was a general be

community that infrasoueffective fish repellent sphysiological basis for uresponse of fish to particdevices are not approprreduction as the early lifdeveloped hearing capainsufficient swimming caentrainment. 
An Addendum To The 316(B) Evaluation Of The Hay

2-10

TABLE 2-3. INITIAL 

SCREENING OF 

FISH 

PROTECTION 

ALTERNATIVES AT 

H

NGS (REVISED 

TABLE 3-1 FROM THE IN

Concept 

Biological 

Effectiveness 

Proven 

Engineering 

Alternative 

Available 

Advantages 

over Other 

Concepts 

Potential for 

Application 

at H

NGS 

Com

Strobe lights yes yes no no Although many studies 

lights as a primary barrioften evaluated as part protection and passage other devices such as sbar racks, bypasses, ansystems. As a secondahave the potential to incprotection effectivenesseffective with larval fish motility. 

Mercury lights no yes yes no Response to mercury lig

be species-specific; somattracted, others repelledemonstrated no obviouthey are not effective wilittle or no motility. 

Chemicals no no no no Use of chemicals has be

some cases evaluated, measures. However, no these devices has been not considered available application at CWISs. 
An Addendum To The 316(B) Evaluation Of The Hay

2-11

TABLE 2-3. INITIAL 

SCREENING OF 

FISH 

PROTECTION 

ALTERNATIVES AT 

H

NGS (REVISED 

TABLE 3-1 FROM THE IN

Concept 

Biological 

Effectiveness 

Proven 

Engineering 

Alternative 

Available 

Advantages 

over Other 

Concepts 

Potential for 

Application 

at H

NGS 

Com

Electric screens no yes no no Electric barriers have be

prevent the upstream paattempts to divert or detmovement of fish have mConsequently, past evapermanent applicationseffectiveness of these bCWISs is unknown. Givineffectiveness and hazscreens are not considefor application at CWISsbehavioral barriers, eleceffective with larval fish motility. 

Air bubble curtain yes yes no no These curtains generall

in blocking or diverting f

applications. Air bubble evaluated at number of with a variety of speciesat these sites have been Air bubble curtains woularval fish that have little 
An Addendum To The 316(B) Evaluation Of The Hay

2-12

TABLE 2-3. INITIAL 

SCREENING OF 

FISH 

PROTECTION 

ALTERNATIVES AT 

H

NGS (REVISED 

TABLE 3-1 FROM THE IN

Concept 

Biological 

Effectiveness 

Proven 

Engineering 

Alternative 

Available 

Advantages 

over Other 

Concepts 

Potential for 

Application 

at H

NGS 

Com

Water jet curtain no yes no no Devices such as water j

suggested, and in some protection measures. Happlication of these devdeveloped, and they are available technologies f

Hanging chains no yes no no Devices such as hangin

suggested, and in some protection measures. Happlication of these devdeveloped, and they are available technologies fIn addition, they are not 

that have little or no mo

Visual keys no yes no no Visual cues have been s

cases evaluated, as fish However, no practical adevices has been develconsidered available tecat CWISs. 

Hybrid barriers (e.g., strobe light /air bubble curtain) 

no no no no No practical application 

been developed, and thavailable technologies fIn addition, they are not 

that have little or no mo
An Addendum To The 316(B) Evaluation Of The Hay

2-13

TABLE 2-3. INITIAL 

SCREENING OF 

FISH 

PROTECTION 

ALTERNATIVES AT 

H

NGS (REVISED 

TABLE 3-1 FROM THE IN

Concept 

Biological 

Effectiveness 

Proven 

Engineering 

Alternative 

Available 

Advantages 

over Other 

Concepts 

Potential for 

Application 

at H

NGS 

Com

Physical Barriers 

Fixed screens yes yes no no As a barrier device, a fix

effective if there is a low and a way for fish to escmesh devices would be reduction. These early limited motility which furpotential for protection f

Conventional traveling water screens 

yes yes no no As barrier devices, trave

considered for protectioaquatic organisms that h

Rotary drum screens yes yes no no Installation of rotary dru

a much larger area than screens because of the 

Barrier net yes yes no no Barrier nets can be cons

for protecting adult fish low velocities (generally can be achieved and deThey would be ineffectivstages that have little or 
An Addendum To The 316(B) Evaluation Of The Hay

2-14

TABLE 2-3. INITIAL 

SCREENING OF 

FISH 

PROTECTION 

ALTERNATIVES AT 

H

NGS (REVISED 

TABLE 3-1 FROM THE IN

Concept 

Biological 

Effectiveness 

Proven 

Engineering 

Alternative 

Available 

Advantages 

over Other 

Concepts 

Potential for 

Application 

at H

NGS 

Com

Bar rack barrier yes yes no no Bar rack barriers are typ

spacing greater than 1 ieffectively prevent the estages. They may, howimpingement. 

Infiltration intakes yes yes no no Radial wells and artificia

successfully used to supwater. While such systebiological impact, they hfor screening large flow application. 

Porous dike yes yes no no Rock structures such as 

dikes allow water to paspassage of juvenile and effectiveness with larval 

Aquatic filter barrier (AFB) 

yes yes no no At this time, the AFB sys

experimental despite its effectiveness. In additioinstallation of this techn

HnGS. 
An Addendum To The 316(B) Evaluation Of The Hay

2-15

TABLE 2-3. INITIAL 

SCREENING OF 

FISH 

PROTECTION 

ALTERNATIVES AT 

H

NGS (REVISED 

TABLE 3-1 FROM THE IN

Concept 

Biological 

Effectiveness 

Proven 

Engineering 

Alternative 

Available 

Advantages 

over Other 

Concepts 

Potential for 

Application 

at H

NGS 

Com

Cylindrical wedgewire screen intakes 

yes yes no no Wedgewire screens hav

both entrainment and imintakes. Effectiveness ithrough-slot velocity, anambient cross-current to debris away. 

Collection Systems Modified traveling (Ristroph-type) screens (coarse- and fine-mesh) with fish protection features 

yes yes yes yes Modified traveling water 

an available technology losses due to impingemThe primary concern witthat they function by implife stages that are entramesh screens. Dependstage, mortality from imentrainment mortality. Balso be considered. 

Fish pumps yes yes no no Hidrostal and Archimed

demonstrated an ability 

little or no mortality. Ththemselves do not repreprotecting fish. Howevebypass systems such as louvers, fish pumps are The effect of the pumps need to be evaluated. 
An Addendum To The 316(B) Evaluation Of The Hay

2-16

TABLE 2-3. INITIAL 

SCREENING OF 

FISH 

PROTECTION 

ALTERNATIVES AT 

H

NGS (REVISED 

TABLE 3-1 FROM THE IN

Concept 

Biological 

Effectiveness 

Proven 

Engineering 

Alternative 

Available 

Advantages 

over Other 

Concepts 

Potential for 

Application 

at H

NGS 

Com

Diversion Systems 

Louvers / angled bar racks 

yes yes no no Due to the large spacing 

louver systems do not pfish. 

Angled screens (fixed or traveling) 

yes yes no no Angled screens can be 

option for protecting juvstages provided that procan be maintained and removed. Fish eggs, lainvertebrates would not screens unless fine-mesAlso, as the length of scsurvival of larvae decreaefficiency improves as f

Angled rotary drum screens 

yes yes no no Installation of angled rot

require an even larger arotary drum screens. 

Inclined plane screens no yes no no No advantage over MIS Eicher screen yes yes no no While biologically effect

was designed for penstono advantage over an M
An Addendum To The 316(B) Evaluation Of The Hay

2-17

TABLE 2-3. INITIAL 

SCREENING OF 

FISH 

PROTECTION 

ALTERNATIVES AT 

H

NGS (REVISED 

TABLE 3-1 FROM THE IN

Concept 

Biological 

Effectiveness 

Proven 

Engineering 

Alternative 

Available 

Advantages 

over Other 

Concepts 

Potential for 

Application 

at H

NGS 

Com

Modular inclined screens (MIS) 

yes yes yes yes The combined results of 

evaluations of the MIS hthis screen is an effectivthat has the potential fointakes. Any consideratapplication should be bascale, prototype evaluatentrainment can be exp

Submerged traveling screens 

no yes no no Designed for partial scre

project intakes. Not app

Modifications to Reduce Intake Flow Modified pump operation 

yes yes yes yes Reducing flow will reduc

entrainment. Flow reduaccomplished by either or with the installation o

follow the load (see belooperating at or near its tthen units would need to reduction. 

Install variable speed drives (VSD) 

yes yes yes yes Variable speed drives c

better regulate intake flodrives would allow HnGgeneration during peak 
An Addendum To The 316(B) Evaluation Of The Hay

2-18

TABLE 2-3. INITIAL 

SCREENING OF 

FISH 

PROTECTION 

ALTERNATIVES AT 

H

NGS (REVISED 

TABLE 3-1 FROM THE IN

Concept 

Biological 

Effectiveness 

Proven 

Engineering 

Alternative 

Available 

Advantages 

over Other 

Concepts 

Potential for 

Application 

at H

NGS 

Com

Install closed-cycle cooling system (mechanical, natural draft and dry cooling towers) 

yes yes yes yes Closed-cycle cooling wi

significantly. Depending cycle system installed aof cycles-of-concentratioin salt water could be reImpingement and entraiaccordingly.
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

3-1

3.0 ENTRAINMENT REDUCTION OPTIONS 

As stated previously, compliance with EPA’s entrainment reduction performance standards will be 

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

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

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

technologies with marine or estuarine species. 

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

HnGS. There are currently no additional data available on the effectiveness of these screens in reducing 

mortality of entrainable organisms. 

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

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

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

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

present. 

3.1 FINE-MESH MODIFIED TRAVELING SCREENS

Alden’s original evaluation reflected several issues relative to this technology that existed in 2004. First, 

the approach velocity to the existing traveling screens exceeds the typical design velocity for this 

technology (i.e., 0.5 feet/sec); existing approach velocities are 0.9 feet/sec at Units 1 and 2, 0.7 feet/sec at 

Units 5 and 6, and 0.6 feet/sec at Unit 8. As such, Alden provided costs based on an expanded 

screenhouse that would accommodate the additional screens needed to reduce the approach velocity. 

Such an expansion would require extensive site work and lengthy unit down time. 

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

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

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

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

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

consider this technology further. The pilot study proposed for LADWP’s Harbor Generating Station 

(which has lower velocities that HnGS) would identify where survival of previously entrained organisms 

starts to occur. 

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

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

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

Unfortunately, Alden could not find adequate data on the West Coast species of interest at HnGS to 

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

Based on discussions between Alden and MBC staff, the following surrogates were used for this 

assessment: 

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 

Silversides 3.8-5.0 Atlantic silversides 0.44 

White croaker 2.2-2.8 Bay anchovy 0.37 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

3-2

West Coast Species Length at hatch 

(mm) East Coast Species Predicted HCD (mm) 

Jacksmelt 7.5-8.6 Bay anchovy 0.74 

Topsmelt 4.3-4.9 Bay anchovy 0.50 

Grunion 6.5-6.7 Bay anchovy 0.67 

Northern anchovy 2.5-3.0 Bay anchovy 0.34 

The data 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 northern anchovy yolk-sac larvae. However, 

to be conservative a 0.2 mm mesh screen was selected to exclude larvae found at HnGS. Based on 

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

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

considerations are associated with the replacement of the existing 9.5 mm mesh screens with 0.2 mm 

screens: 

• Increase head loss – Head loss will increase from 0.2 to 5 inches in a clean condition, and 2 to 24 

inches at 50% blocked with debris. 

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

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

the smaller opening. 

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

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

large debris. More frequent screen replacement is expected. 

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

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

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

installation. 

The location of the existing traveling screens presents another issue. Impinged and entrainable organisms 

collected from the screens will have to be transported a considerable distance to a safe release point. In 

addition, fish and shellfish species and their associated life stages tend to vary considerably in terms of 

their ability to tolerate the collection and handling associated with this option, which emphasizes the need 

for species and life stage specific testing to verify survival rates. As stated previously, 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. 

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

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

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

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

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

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

Conclusion 

Fine-mesh traveling screens are technically an “exclusion technology.” However, unlike narrow-slot, 

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

impinged fish and debris away from the CWIS, this technology utilizes a “trap and transfer” concept. The 

process of collecting organisms to assess survival imparts some level of mortality that is difficult to 

ascertain in the field. Consequently, the projected efficacy of this technology will be less than that for 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

3-3

narrow-slot, wedgewire screens. The life stages that dominate the entrainment numbers at HnGS are such 

that this technology would probably not meet the entrainment reduction standard. 

3.2 MODULAR INCLINED SCREENS

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

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

alternatives, Alden proposed consideration of the MIS for reducing larger entrainable organisms. Results 

of species-specific survival from pilot studies of both the fine-mesh traveling screens and the MIS could 

be compared to develop overall efficacy. 

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

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

the system is submerged. The current heat treatment practices used with the existing screens (that would 

be effective, for underwater biofouling of the traveling screens) would have to be relocated to be 

applicable here. If the MIS proved effective, and biofouling issues were documented during the pilot 

tests, a heat treatment alternative could be considered. 

Conclusion 

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 

the MIS will meet the entrainment reduction standard. The results of the pilot study will remove this 

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

3.3 FLOW REDUCTION 

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

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

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

1978/1979 studies hold true, there are no substantial day/night differences and entrainment is not 

concentrated on a seasonal basis. This would eliminate the ability to target flow reductions during 

periods of high entrainment. Tenera and MBC are in the process of completing the entrainment study 

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

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

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

retrofit pumps with variable speed drives (VSDs). The VSDs would allow much finer control of flow 

reductions while ensuring adequate flow to meet heat rate and generation needs. Also, the question of 

whether design or actual flow can be used for the calculation baseline needs to be considered. If the 

calculation baseline is based on design flow this option could be especially attractive for Units 1 and 2. 

Under design flow it is assumed that all pumps for all of HnGS Units operate 24 hours/day, 365 days / 

year. As pointed out in the Proposal for Information Collection (PIC), the HnGS Units have capacity 

factors that have averaged approximately 16% (Unit 6) to 30% (Unit 2) between 1999 and 2005. 

Generally, there is some correlation between capacity utilization and pump operation, since it does not 

make sense incur the cost of operating the cooling water pumps when electricity is not being generated. 

Facility staff stated this to be the case for HnGS during the site visit. Thus using the design flow 

assumption, HnGS could take credit for the flow reduction when the cooling water pumps normally do 

not operate. Due to relatively low capacity utilization, this could generate a significant entrainment 

reduction credit at very little cost since no energy penalty would be required. The only concern would be 

that if there is a significant increase in capacity utilization for these Units in the future, additional 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

3-4

entrainment reduction actions could be required. However, under actual flow, flow reduction credits can 

only be taken by reducing flow from current operations. Regardless, it is unlikely that flow could be 

reduced sufficiently to meet the current performance standard range. 

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

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

associated with VSDs. Some key operational issues that would need to be addressed are: unbalanced 

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

waterboxes, vibration of the pumps at lower speeds, and potential to burn out the existing motors. This 

review will further identify the limitations that may exist and provide recommendations for each unit 

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

following upgrades are not included in our cost estimate; but would be required prior to installing VSDs: 

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

2. Installation of pump discharge valves; 

3. New circulating water pumps; and 

4. New pump motors. 

Conclusion 

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

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

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

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

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

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

minimize lost generation. Costs have been included in this Addendum. Regardless, this option by itself 

would not likely meet the entrainment reduction standard. 

3.4 CLOSED-CYCLE COOLING

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

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

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

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

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

that the cost of a national retrofit cannot be borne by industry. However, if EPA identified closed-cycle 

cooling as BTA, it would be considered the “best performing” technology. Under this scenario, the CostCost 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. 

Finally, should LADWP move forward with re-powering of Units 5 and 6, use of closed-cycle cooling 

should be considered as part of the project. This would provide not only an overall facility flow reduction 

credit, but provide a benefit in addressing the thermal loading concerns in the San Gabriel River. Time 

constraints do not allow for an effective assessment of the various options to be considered for the repowering. 

Conclusion 

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

required to meet the standard is not know at this time. Cooling towers would have the highest overall 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

3-5

capital and operating & maintenance (O&M) cost of all of the alternatives. However, as part of repowering Units 5 and 6, closed-cycle cooling may be a cost-effective alternative. 

3.5 ADDITIONAL TECHNOLOGIES 

During discussions, an alternative of using narrow-slot, wedgewire screens in the station “forebay/end-ofcanal” in conjunction with fish-friendly bypass pumps was suggested. To function effectively, a 

wedgewire screen system requires an “ambient” flow to remove impinged fish and debris; the bypass 

pumps would provide this flow. The following discussion relates to existing conditions and does not take 

into account the Units 5 and 6 re-powering potentials. 

Alden has considered this option under the current HnGS operations. A total of 56, T-84 narrow-slot (0.5 

mm) wedgewire screens would be needed. A narrower slot size was not considered as 0.5 mm is currently 

the smallest slot size available for cylindrical screens. A 0.2 mm slot wedgewire screen can be provided; 

however, the number of screens required is substantial (i.e., approximately 120 for HnGS). The vendor 

also questions whether the air-burst backwash system would function effectively since it is anticipated 

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

Due to the number and size of the screens required to assure the 0.5 feet/sec through-slot velocity, the 

screens would need to be mounted to a long, bulkhead wall that would isolate the flow through the 

screens from the flow down the canal. This bulkhead wall would reduce the cross-sectional area of the 

intake canal by approximately 25% near the screens. 

To provide a sweeping flow, bypass pumps would be added at the terminus of the canal. A sweeping 

flow of 1.0 feet per sec (ft/s) is considered adequate to assure removal of backwashed fish and debris for 

this configuration. The bypass flow would be approximately 700 cubic feet per second (cfs), which could 

be provided with several fish-friendly pumps located in a new pumphouse at the terminus of the intake 

canal. The actual bypass flow required would be dependent on the final layout of the screens and the 

expected unit operations. Biofouling could be minimized by using screens made of Z-alloy, an antibiofouling nickel-copper alloy. The discharge of the bypass pumps (return pipes) would be subject to the 

same biofouling concerns associated with other technologies. If LADWP were to entertain this option, 

Alden would strongly recommend conducting hydraulic or physical modeling of this option for which 

costs are not included. A conceptual design and cost estimate of this wedgewire screen configuration in 

the canal with a bypass pump system are provided in Attachment F. 

During the conference call on January 30, 2007, another option of an angled, flat-panel wedgewire screen 

with a bypass pump was also suggested. Assuming an average depth of 10 feet (in Long Beach Marina) 

and a through-slot velocity of 0.5 ft/s, a screen with a 0.5 mm slot opening with 50% porosity placed 

perpendicular to the flow would be 600 feet in length. If the porosity were 30% the length would increase 

to 1,000 feet. However, to provide guidance to the bypass pump, the screen would have to be placed at an 

angle to the intake flow. A screen with 50% porosity angled at 45o or 30o to the flow would be 840 and 

1,200 feet long, respectively. At 30% porosity, the lengths would increase to 1,400 and 2,000 feet, 

respectively. An installation of this magnitude is clearly impractical for consideration in Long Beach 

Marina. If this installation were considered within the intake canal, the length of the screens would be cut 

roughly in half (assuming a 20-foot canal depth). Larval fish and entrainable sized organisms do not have 

the sustained swimming speeds necessary to effectively respond to this type of technology. Therefore, this 

option has not been considered further. 

Alternatively, if the Gunderboom “Marine Life Exclusion System” (MLES) were to be considered in the 

intake canal, an MLES 4,700 feet in length would be required at a 45o angle to the flow; at a 30o to the 

flow, the MLES would be 6,700 feet long. A cost estimate for this option has not been developed. 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

3-6

Finally, there was discussion of the potential to tunnel offshore to install cylindrical wedgewire screens. 

Alden estimates that at a minimum a two-mile-long tunnel would be required. This tunnel would have 

the same biofouling problems currently experienced at all California facilities with offshore intakes. In 

addition, the distance would not allow use of the air-burst backwash system. A conceptual design and a 

cost estimate have not been developed for this option. 

Conclusion 

Either variation of the wedgewire technology or MLES that requires use of a bypass pump would 

certainly be questioned as to the efficiency of “moving” fish and debris removed from the system(s) to the 

bypass pump and the effect of the pump passage on survival. The only available guidance/survival data 

with West Coast species indicate that guidance efficiency and survival improve as fish grow. However, 

survival of fish <20 mm is poor (LMS 1981). In addition, the organisms would have to be returned to a 

safe point of discharge, which further confounds a valid assessment of efficacy. Alden does not believe 

this approach could be proven to be effective in meeting the entrainment reduction performance standard. 

It is also Alden’s belief that an intake “extension” project to consider wedgewire screens at an offshore 

location would not be practicable. 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

4-1

4.0 IMPINGEMENT MORTALITY REDUCTION OPTIONS 

As stated previously, technologies considered for compliance with EPA’s entrainment reduction 

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

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

reduce entrainment are also valid when considering impingement. The following addresses these 

technologies with consideration of updated information developed since 2004.

4.1 COARSE-MESH MODIFIED TRAVELING SCREENS

The velocities approaching the existing traveling water screens are 0.9 ft/s at Units 1 and 2; 0.7 ft/s at 

Units 5 and 6, and 0.6 ft/s at Unit 8. These velocities are within the range of velocities that provide good 

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

screens in Alden’s original report). Limited survival data exist for species impinged at HnGS. Therefore, 

Alden still recommends conducting pilot studies before full-scale installation. If a pilot-scale study to 

document impingement survival rates was conducted at LADWP’s Harbor Generating Station (which has 

lower velocities than HnGS), the results would also apply to survival of impinged organisms at HnGS. 

The location of the existing traveling screens presents another issue. Impinged organisms collected from 

the screens will have to be transported a considerable distance to a safe release point. In addition, fish 

and shellfish species and their associated lifestages 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. As stated previously, Alden believes that methods 

exist for maintaining a clean fish return system. Two potential options are summarized in Attachment C. 

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

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

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

component of the pilot study. However, rather than confound the biological assessment component of the 

study, it may be desirable to conduct a small-scale, focused study for evaluating biofouling conditions. 

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

Conclusion 

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

The ability to meet the impingement mortality performance standard would depend on the species present 

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

4.2 MODULAR INCLINED SCREENS

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

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

is conducted for entrainment reduction, the results of species-specific survival would be used to develop 

overall efficacy, which would include impingement survival. 

As discussed in Section 3.2, all the ancillary issues associated with traveling water screens (e.g., handling 

and long-distance transport) apply to MIS. The one exception would be elimination of the concern with 

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

existing screens (that would be effective, for underwater biofouling of the traveling screens) would have 

to be relocated to be applicable here. If the MIS proved effective, and biofouling issues were documented 

during the pilot tests, a heat treatment alternative could be considered. 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

4-2

Conclusion 

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

screen option, Alden is uncertain if this standard could be met with the species present at HnGS. 

4.3 FLOW REDUCTION 

Prior to the Court’s Decision, EPA was considering issuing guidance relative to the relationship of 

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

assume proportionality between flow and impingement. HnGS has completed its year of impingement 

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

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

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

generation required to meet an impingement mortality reduction standard of 80-95% is not practical or 

cost-effective.

Conclusion 

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

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

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

pumps during high periods of impingement would result in the need to derate the unit(s) 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 option would likely meet the impingement mortality reduction standard. 

4.4 CLOSED-CYCLE COOLING

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

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

economic penalties associated with this option. 

Conclusion 

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

reasonable to consider it for impingement only. 

4.5 ADDITIONAL TECHNOLOGIES

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) requires low through-net velocities to exclude fish. The 

limitations discussed above for consideration of any installation in Long Beach Marina are also valid for 

this option. In addition, placement within the intake canal is also questionable. Impingeable-size fish can 

avoid the net; however, the canal velocity is 1.3 feet/sec and the through-tunnel velocity is 5.0 feet/sec. A 

fish that is excluded from continuing down the canal could not return to the marina basin. Therefore, 

Alden does not consider a passive screening system to be a viable alternative for HnGS. 

The concept of installing cylindrical wedgewire screens in the intake canal discussed in Section 3 can also 

be considered for impinged fish. However, the efficacy of the bypass pump with impinged fish would 

have to be determined. 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

4-3

Finally, diversion systems such as angled screens or louvers for impingeable-size fish would be 

comparable to the systems discussed above for entrained fish. Cost estimates for this option have not 

been developed. 

Conclusion 

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

of impingement-only options in light of the Court’s Decision. 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

5-1

5.0 COST UPDATE 

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

original report. The update includes an escalation from 2004 dollars to 2006 dollars, as well as changes in 

the site-specific factors that impact the installation and O&M of the compliance alternatives. The detailed 

costs for a fish return systems for Ristroph screens and the costs for the fish bypass pipes associated with 

narrow-slot, wedgewire screens in the intake canal are provided in Attachments C and D, respectively. 
An Addendum To The 316(B) Evaluation Of The Hay

5-2

TABLE 5-1.

ALDEN’S 

APPRAISAL 

LEVEL 

COSTS OF 

EVALUATED 

ALTERNATIVES[LRT1]

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

I

New screenhouses with fine-mesh Ristroph screens with return Option 1

4

$18,373,000 0 $18,373,000 $1,267,000 6,899 $2,616,000 

New screenhouses with fine-mesh Ristroph screens with return Option 2

5

$19,518,000 0 $19,518,000 $1,267,000 6,899 $2,779,000 

Install coarse-mesh Ristroph screens with return Option 1

4

$8,965,000 0 $8,965,000 $987,000 5,585 $1,276,000 

Install coarse-mesh Ristroph screens with return Option 2

5

$10,110,000 0 $10,110,000 $987,000 5,585 $1,439,000 

Install MIS in intake canal $6,417,600 0 $6,417,600 $34,000 2,240 $914,000 Limit the number of operating pumps $0 0 $0 $0 1,437,357 $0 Install variable speed drives on the CWP

6 $3,427,000 0 $3,427,000 0 0 $488,000 

Retrofit plant with closedcycle cooling system

7 $236,544,000 1,468,000 $309,944,000 $4,726,400 64,259 $39,594,000 

Narrow-slot wedgewire screens with 1,000 foot return pipe

8

$42,693,000 489,000 $67,143,000 $8,430,000 164,973 $8,049,000 

Narrow-slot wedgewire screens with a 15,000 foot return pipe

8

$88,930,000 489,000 $113,380,000 $16,855,000 328,948 $14,632,000 

 Footnotes on next page. 
An Addendum To The 316(B) Evaluation Of The Hay

5-3

Table 5-1 Footnotes 1. Based on a cost for lost generation of $50 per MWh.2. Includes costs as a result of any power penalties associated with the technology. 3. Alden assumed a discount rate of 7%, and an amortization rate of 10 years for the capital costs and 30 years for the pilot study and dow4. Return Option 1 uses a single return pipe and relies on a heat treatment to clean. 5. Return Option 2 uses two return pipes in which one pipe is dewatered and left to dry during cleanings.

6. Variable speed drives alone will not meet the entrainment standard and would have to be used in combination with other technologies. 7. Cooling tower costs based on EPRI study (EPRI 2002a). 8. Costs are based on detailed quantity take-offs in Attachment D. 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

6-1

6.0 DATA GAPS AND UNCERTAINTIES 

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

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

further exacerbated by the variability of the biological community characteristics (e.g. diel/seasonal 

abundance, life stage, species) at the site. 

The following table provides a summary of these uncertainty considerations for each of the alternatives 

considered in 2004 and in this document for HnGS. 

Alternative Data Gaps Uncertainties 

Fine-mesh Traveling Screens  Length and species-specific 

survival data from the screen 

and fish return line; 

 Biofouling impacts; and 

 Plant-side return survival. 

 Effective mesh size; 

 Effective approach velocity; 

and 

 Annual variability in species 

composition. 

Coarse-mesh Traveling Screens  Length and species-specific 

survival data from the screen 

and fish return line. 

 Biofouling impacts; and 

 Plant-side return survival. 

 Annual variability in species 

composition. 

Modular Inclined Screens  Length and species-specific 

survival data from the screen 

and fish return line; 

 Biofouling impacts; 

 Plant-side return survival; and 

 Only 2.0 mm slot width has 

been tested. 

 Effective mesh size; 

 Effective approach velocity; 

and 

 Annual variability in species 

composition. 

Narrow-slot Wedgewire Screens 

with Fish-friendly Bypass Pumps 

 Length and species-specific 

exclusion data; 

 Length and species-specific 

survival data to the bypass 

pumps, through the bypass 

pumps, and through the fish 

return line; 

 Biofouling impacts; and 

 Plant-side return survival. 

 Effective mesh size; 

 Effective “sweeping” 

velocity; and 

 Annual variability in species 

composition. 

Flow Reduction   Generation demand; and 

 Annual variability in species 

composition. 

Closed-cycle Cooling Unit-specific retrofit. 

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

only be reduced by extended abundance sampling (i.e. IM&E studies) or alternative/component-specific 

pilot studies. Each technology will have a different efficacy for reduction in station effects. The pilot 

studies proposed for LADWP’s Harbor Generating Station (i.e. fine-mesh traveling screens) and HnGS 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

6-2

(i.e. MIS) will provide data on length-related, species-specific survival. The results of both studies would 

also provide survival data that apply to impingement (coarse-mesh screens). Macrofouling on the 

continuously operating screens can be determined during the pilot studies as well as debris handling 

capabilities. 

The type of study to assess efficacy of the narrow-slot wedgewire alternative at HnGS is complex. The 

study would effectively be based on a biological mass balance. The mass balance would first require a 

comparison of the density and condition (i.e. live or dead) of entrainable-sized organisms within the 

intake canal upstream of the wedgewire complex and downstream of the complex prior to passage 

through the bypass pump. The survival of the organisms through the pump would then be determined by 

concurrently sampling the pump discharge with the “pre-pump” inlet sample. This second effort may be 

unnecessary if the results of the first component are unfavorable. 

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 

above studies were available. 

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

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

survival among “hearty” and “fragile’ species will vary and a change in composition towards “fragile” 

species will jeopardize compliance potential. 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

7-1

7.0 CONCLUSIONS 

This assessment indicates that: 

• The re-powering project for Units 3 and 4 reduced flow by approximately 5% and slightly 

lowered velocities within the intake canal. This flow reduction should be considered when 

developing deviations from the calculation baseline. However, the differences do not change any 

of Alden’s original technology assessments. 

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

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

the “trap and transfer” concept and require the same type of fish and debris returns as Ristroph 

screens. The potential use of either of these technologies does not change Alden’s previous 

assessment. 

• The 2006 impingement and entrainment data do not alter Alden’s selection of appropriate 

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

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

stages. 

• The Court’s Decision to remand restoration and the cost-benefit test severely limit LADWP’s 

options, but do not affect Alden’s technology and operational measures assessments. 

• 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. The 

station effects of installation of closed-cycle cooling associated with the re-powering of Units 

5and6 are not included at this time. 

 Fine-mesh traveling screens are technically an “exclusion technology.” However, unlike 

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

ambient currents to “carry” impinged fish and debris away from the CWIS, this technology 

utilizes a “trap and transfer” concept. The process of collecting organisms to assess survival 

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

projected efficacy of this technology will be less than that for narrow-slot, wedgewire 

screens. 

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

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

fine-mesh screens, this alternative may be as effective as the other fine-mesh screen options. 

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

need to be discussed with Corporate Power Supply. Assessment of general trends in load 

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

reduction credit. Use of variable speed drives could be considered to better control flow 

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

standard. 

 Either variation of the wedgewire technology or MLES that requires use of a bypass pump 

would certainly be questioned as to the efficiency of “moving” impinged fish and debris to 

the bypass pump and the effect of the pump passage on survival. Alden does not believe this 

approach could be proven to be effective in meeting the entrainment reduction performance 

standard. An offshore installation of wedgewire screens was not considered practicable. 

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

determine the “best performing” entrainment reduction technology. 
 An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

7-2

• Conclusions for impingement only: 

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

reduction. 

 Consideration of flow reduction remains a possible impingement mortality reduction 

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

alternative. 

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

consideration of impingement-only options in light of the Court’s Decision. 

 Based on the Court’s Decision, it is anticipated that a schedule extension will be provided to 

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

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

1

ATTACHMENT A - 

SUMMARY OF 2004 EVALUATION OF HNGS 

The following provides a summary of the “Evaluation of the Haynes Generating Stations with respect to 

the Environmental Protection Agency’s 316(b) Rules for Existing Facilities”, December 2004, prepared 

by Alden Research Laboratory, Inc. (Alden) and Electric Power Research Institute (EPRI). 

Scope of the Analysis

In response to the Rule, EPRI and Alden conducted a strategic assessment for Los Angeles Department of 

Water and Power (LADWP) Haynes Generating Station (HnGS). This assessment evaluated the impact 

of the Rule on HnGS, including potential cost-effective compliance alternatives, additional information 

collection needs, and relative budget impacts as a result of studies and compliance alternatives. 

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

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

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

meeting the applicable performance standards. 

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

implement to meet the Rule. EPA’s favored approach was to reduce total fish losses, which did not 

address AEI at the population and ecosystem levels. Therefore, traditional measures of population and 

ecosystem health, such as species diversity and richness were not addressed. Further, EPA did not 

consider factors that influence populations such as compensatory mechanisms, species fecundity, and 

natural mortality. Therefore, these factors were not considered. 

Technologies and Operational Measures

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

by LADWP to meet the impingement mortality and entrainment (IM&E) standards at HnGS was 

presented in the report. 

Alden’s preliminary judgment on how likely these alternatives were to actually meet these standards was 

summarized as follows: 

Alternative 

Will It Meet the Impingement 

Mortality Reduction 

Standard? 

Will It Meet the 

Entrainment Reduction 

Standard? 

New screenhouses with fine-mesh 

Ristroph screens 

Yes, provided that impingement 

survival of key species is at least 

80% 

Yes. 

Install coarse-mesh Ristroph 

screens in existing screenhouses 

Yes, provided that impingement 

survival of key species is at least 

80% 

No 

Install Modular Inclined Screens 

(MIS) in existing intake canal Yes 

No. However, some reduction 

in entrainment of larger 

organisms is expected as a 

result of the 2 mm slot size 

Limit the number of operating 

pumps 

No; we might expect some 

reduction in the number of fish 

impinged 

Yes, with a 60% reduction in 

plant flow 

Retrofit plant with closed-cycle 

cooling system Yes Yes 
Attachment A An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

2

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

were: 

Alternative Alden’s Annualized Costs EPA’s Annualized Costs 

New screenhouses with finemesh Ristroph screens $3,397,000 

Install coarse-mesh Ristroph 

screens in existing screenhouses $1,899,000 

Install MIS in existing intake 

canal $936,000 

Limit the number of operating 

pumps 

$57,494,000 

Retrofit plant with closed-cycle 

cooling system $45,099,000 

$1,237,176 

Key findings of our preliminary (2004) analysis are: 

• The existing Cooling Water Intake Structure (CWIS) will not meet the IM&E performance 

standards. 

• Five technological or operational options (i.e. build new screenhouses and install fine-mesh 

Ristroph screens; install coarse-mesh Ristroph screens in existing screenhouses; install MIS units; 

limit pump operation; and closed-cycle cooling) were considered to have potential for meeting 

the impingement mortality and/or entrainment reduction standards and were deemed practicable 

from an engineering standpoint. Technologies that solely reduce impingement were also 

evaluated in case LADWP were to meet the IM standard with a technology while meeting the 

entrainment standard through operational changes or initiating restoration measures. 

• For the three options that could meet the entrainment reduction standard, Alden estimated the 

annualized costs range from $3,397,0003 for new screenhouses with fine-mesh Ristroph screens 

to $57,494,000 for reducing flow during periods of high entrainment. 

• Coarse-mesh Ristroph screens in the existing screenhouses would meet the impingement 

mortality (IM) reduction standard at an annualized cost of $1,899,000. Fine-mesh Ristroph 

screens in the existing screenhouses may be able to meet both the IM&E standards and would 

have a cost similar to that of coarse-mesh Ristroph screens. Pilot studies would be required to 

prove the effectiveness of fine-mesh Ristroph screens at the velocities in the existing 

screenhouses. 

• MIS units installed in the intake canal were the most cost effective alternative to meet the IM 

reduction standard with an annualized cost of $936,000. As the MIS units are designed with 2 

mm slots, they would also reduce entrainment of larger organisms. 

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

protection technologies for application at HnGS. 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 HnGS. The criteria were: 

• Alternatives should be designed to reduce impingement mortality by 80–95% from the 

“calculation baseline.” 

 

3

 See Table 6-1 (Revised) for updated costs. 
Attachment A An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

3

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

baseline.” 

• Alternatives should provide protection for species that are potentially susceptible to IM&E at 

HnGS. 

• The period of protection is year-round for impingement and May through August for entrainment. 

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

Table 3-14. 

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

intake flows and water depths at the CWIS. 

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

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

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

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

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

• Alternatives should meet worker and public safety requirements. 

• Alternatives should not adversely impact navigation. 

• Alternatives should be compatible with the other aesthetic and recreational features of the region. 

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

fish protection schemes under physical, hydraulic, and in environmental conditions that they have never 

been applied, the Team had to use best professional judgment based upon experience. 

The Team deemed a technology to have proven biological effectiveness if test data (preferably from fullscale application) were available that documented a technology’s effectiveness with one or more 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 if 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 the results of laboratory and cage test 

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

have been evaluated for repelling or guiding juvenile and adult fish away from water intakes (EPRI 1994, 

1999) and, in many cases, toward bypasses for transport to a safe release location. There is some 

evidence that combining strobe lights with an air bubble curtain can provide effective fish deterrence. 

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

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

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

Alosa (American shad, alewife and blueback herring) at sites throughout the U.S. (Ploskey et al. 1995; 

 

4

 See Table 3-1 (Revised) for updated assessment. 
Attachment A An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

4

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 years, a hybrid barrier 

consisting of light, sound, and air bubbles would be most effective on Alosids. Given that Alosids are not 

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

impingement mortality reduction standard, and thus the Team eliminated these types of barriers from 

further consideration at HnGS. 

The existing screenhouses at HnGS could be modified for installation of Ristroph screens. Ristroph 

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

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

screens with an approach velocity of 0.5 feet/sec have the potential to meet both standards, while coarsemesh Ristroph screens may meet only the IM standard. In addition, Ristroph screens are designed for 

continuous operation to minimize impingement duration. Continuous rotation along with spray wash 

systems provides the Ristroph screens with an automatic screen-cleaning feature. This gives them an 

engineering advantage over fixed-screens, barrier nets, and bar rack barriers, all of which would require 

an additional cleaning system. Fine-mesh Ristroph screens with expanded screenhouses are considered to 

be a viable alternative for reducing both impingement and entrainment mortality at HnGS. Coarse-mesh 

screens in the existing screenhouses were also evaluated, since HnGS may choose to meet the entrainment 

reduction standard through other compliance measures. 

Modification of the screenhouse to incorporate physical barriers or diversion systems, such as angled 

screens to prevent impingement, would be difficult. Traveling water screens have an engineering 

advantage over other physical barriers (i.e. angled fixed-screen, rotary drum screen, barrier net, bar rack 

barrier, infiltration intakes, and porous dikes). Installation of rotary drum screens and porous dikes would 

require a much larger area than conventional traveling screens because of the lower design velocity. 

Rotary drum screens are typically installed in channels where water elevations are relatively constant and 

water depths are less than 12 feet, which is not the case at the HnGS facility. Bar rack barriers are 

typically designed to have spacing greater than 1 in. and would not effectively prevent the entrainment of 

early life stages. They may, however, effectively reduce impingement. None of these options were 

evaluated further because they do not have significant advantages over other impingement mortality 

reducing technologies. 

The 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 screening concepts. The MIS, for example, is designed 

to operate at velocities up to 10 feet/sec. The Eicher screen is designed for installation in hydroelectric 

project penstocks and rejected for consideration at HnGS. An MIS configuration located in the intake 

canal was chosen for further evaluation because the MIS should be easier to build and maintain than other 

diversion systems. 

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

and bar rack barriers. Wedgewire screens are designed for a through-screen velocity of 0.5 feet/sec; 

therefore, automatically meeting the impingement mortality (Compliance Option 1) standard. Wedgewire 

screens have cleaning features that make them easier to clean than other fixed screens and barrier nets. 

However, this cleaning feature requires the presence of a sweeping current to be effective. In the marina 

wedgewire screens would be a navigational obstruction, and in the intake channel, there would be no 

sweeping current to help clean the screens. For these reasons, wedgewire screens were not included in 

the preliminary evaluation for HnGS. 

Aquatic filter barriers (AFB) could perform a similar function to fine-mesh traveling water screens. An 

AFB has two layers of material with an air purge system installed between the layers to permit automatic 
Attachment A An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

5

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

other non-motile life stages. However, this technology requires an extremely large surface area. An AFB 

at HnGS would be impossible to place within the marina due to the amount of surface area required. 

Therefore, this technology was not considered a viable alternative for HnGS. 

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

are considered experimental for reducing entrainment. However, coarse-mesh nets could reduce 

impingement if they were installed in a low velocity zone and periodically cleaned to remove debris 

accumulation and biofouling growth. Barrier nets require less surface area than AFBs, although they 

would still hinder navigation and recreation at the Long Beach Marina. Therefore, barrier nets were not 

included as an option to reduce impingement at HnGS. 

The preliminary screening of intake technologies available for fish protection indicated that installation of 

fine-mesh5 Ristroph screens with an expanded intake was the one intake alternative that had the greatest 

potential for application to reduce fish impingement mortality and entrainment at HnGS: 

Two additional intake alternatives that would act to reduce fish impingement only were also included: 

• Installation of coarse-mesh Ristroph screens in existing intake; and 

• Installing modular inclined screen (MIS) in intake channel 

Two flow reduction options were identified to reduce entrainment and, to a lesser extent, impingement: 

• Reduced circulating water pump operation; and 

• Installing closed-cycle cooling system 

Plant operating procedures dictated operation of all pumps per unit to maintain the plant discharge within 

the permitted thermal limits. Additional flow limitations could be implemented during periods of peak 

abundance of entrainable organisms. To maintain the plant discharge within the permitted thermal limits, 

reduced pump flow may require a reduction in plant output. Variable speed drives were selected as the 

flow reducing technology. 

Closed-cycle cooling could greatly reduce both impingement mortality and entrainment at HnGS. 

Mechanical or natural draft wet towers would require less modification to the existing circulating water 

system piping and less real estate than dry cooling towers. The costs for construction of a wet mechanical 

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

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

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

towers. HnGS is surrounded by residential, recreational, and park areas, therefore aesthetics and air 

quality issues would probably rule out the use of natural draft towers. For these reasons, the Team 

evaluated wet mechanical draft towers as the closed-cycle cooling system option for HnGS. 

 

5

The term “fine-mesh,” as used in this document, refers to 0.5 mm (0.02 in.) square woven mesh. 
Attachment B An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

1

ATTACHMENT B - 

LADWP RESTORATION OPTIONS 

1.0 INTRODUCTION 

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

a 316(b) strategic assessment for the Los Angeles Department of Water and Power’s (LADWP) 

Generating Stations; Harbor Generating Station (HGS), Haynes Generating Station (HnGS), and 

Scattergood Generating Station (SGS). As part of that assessment, the use of restoration as a 316(b) 

compliance alternative was evaluated. That evaluation analyzed restoration project categories, and 

included summaries of nationwide restoration projects. 

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

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

Stations, summarize the process of implementing restoration projects, and identify data gaps that are 

required to be addressed prior to developing a 316(b) Restoration Plan for inclusion in the Comprehensive 

Demonstration Study for each Generating Station. 

2.0 SUMMARY OF 2004 ALDEN/EPRI RESTORATION EVALUATION 

2.1 TYPES OF RESTORATION APPLICABLE TO 316(B) 

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

other facilities nation-wide. These included: 

• Wetlands restoration; 

• Fish stocking; 

• Submerged aquatic vegetation (giant kelp) restoration; 

• Provision of fish passage; 

• Contribution to a restoration fund; and 

• Water quality improvements. 

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

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

appropriate because meeting the performance standards through implementation of technologies and/or 

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

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

the use of restoration will produce ecological benefits (production of fish and shellfish) at a level that is 

substantially similar to that which would be achieved through implementation of technologies, 

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

2.2 SPECIFIC RESTORATION EXAMPLES FOR HGS, HNGS, AND SGS 

Alden/EPRI provided several examples of potential restoration projects applicable to LADWP’s coastal 

generating stations. These examples are summarized below. 

Fish Stocking

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

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

shad (Susquehanna River, Maryland/Pennsylvania), and white seabass (southern California). 
Attachment B An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

2

Habitat Protection Programs

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

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

of fish production. Examples included the San Dieguito Lagoon restoration (SCE San Onfore), the Morro 

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

Program (PSEG), and the Santa Monica Bay Restoration Commission (Los Angeles, California). Other 

examples were provided related to restoration-related groups that might assist in the facilitation of 

restoration projects, including the National Centers for Coastal Ocean Science, the National Estuaries 

Restoration Inventory, the NOAA Community-based Restoration Program, the U.S. Fish and Wildlife 

Service Partnership for Fish and Wildlife, and Coastal America’s Corporate Wetlands Restoration 

Partnership. 

Dam Removal or Fishway Construction

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

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

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

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

Creek). 

Alternative Restoration Projects

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

contaminated sediments to improve water/sediment quality and habitat. 

2.3 316(B) RESTORATION IMPLEMENTATION PROCESS

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

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

would fund and manage in cooperation with federal, state, and local resource agencies, the process could 

include the following at a minimum: 

• Identify projects with involvement of resource agencies and stakeholder groups using an 

approach similar to the process described in Section 3.4. 

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

entrainment (IM&E). 

• Develop implementation plan for restoration with input from resource agencies and stakeholder 

groups including: 

 Setting goals for project 

 Defining milestones that can be used to measure performance 

 Conducting initial biological and engineering data for plan 

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

goals for offsetting IM&E losses are achieved 

 Ensuring that the plan incorporates adaptive management so that restoration activities and 

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

• Prepare information for permitting 

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

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

and monitoring plans. 

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

• Review proposals and select contractors for management, construction, and monitoring. 
Attachment B An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

3

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

reviews involving resource agencies and stakeholders. 

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

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

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

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

example of the successful implementation of this approach is the funding provided from the Moss 

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

preservation and enhancement of the Elkhorn Slough National Estuarine Research Reserve (see attached). 

The success of this program has been widely recognized, and is largely due to the maturity of the 

management plan for the slough that was developed by the ESF. The ESF has been able to leverage the 

money provided by MLPP many times over to accomplish much more than could ever be achieved from a 

single restoration project. The successful implementation of this approach requires identifying an existing 

entity like the ESF that has a proven track record with implementing restoration programs. 

3.0 SPECIFIC RESTORATION PROJECTS APPLICABLE TO HAYNES 

GENERATING STATION 

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

to the HnGS, and identify data necessary if each project were to be selected for implementation. Potential 

restoration projects should be considered based on their ability to offset entrainment and/or impingement 

at HnGS. 

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 HnGS (Los Angeles and 

Orange counties); 

• Projects that enhance habitat through watershed management; and 

• Projects that enhance the nearshore coastal environment in the vicinity of HnGS (Santa Monica 

Bay and San Pedro Bay). 

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

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

tidal flow between the ocean and the wetlands to historic levels would have a similar affect on 

productivity. Other projects that involve watershed management could reduce wetland sedimentation and 

thus preserve existing wetland habitat. Projects that enhance the biological productivity of Santa Monica 

and San Pedro bays could directly offset the loss of productivity in the same waterbody that occurs as a 

result of IM&E losses at the three power plants. 

The “value” of the ecological services or benefits that will result from implementation of any of these 

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

“credits” gained through restoration will outweigh the ecological “debits” caused by the IM&E losses. 

Using local environmental planning documents and resource agency recovery plans as references, three 

major categories of projects have been identified that are appropriate for inclusion as restoration 

alternatives to offset IM&E losses. These projects have the potential to create, restore and preserve 

habitat equivalent to the amount of habitat that produced the estimated numbers of impinged and 

entrained species of fishes and target invertebrates, as well as the other ecological and environmental 

effects of I&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. 
Attachment B An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

4

3.1 COASTAL WETLAND PROJECTS

At one time coastal lagoons, salt marshes, and other wetlands created by the merging of creeks and rivers 

with the Pacific Ocean characterized the shoreline of Santa Monica Bay, Los Angeles and Long Beach 

Harbors, and shoreline areas further south. As these coastal areas became more densely populated, and 

more highly developed, most of the marshes were filled and the creeks and rivers were channeled into 

concrete waterways to eliminate the periodic flooding that plagued these low lying areas. In recent years, 

public sentiment has turned to the task of preserving the remaining wetlands in this area and, where 

possible, to restoring those wetlands to a state that more closely resembles historic conditions. 

This category of projects includes actions taken directly within the boundaries of these wetlands to restore 

and/or enhance habitats that serve as spawning grounds for fish and other aquatic species. Projects in this 

category include the restoration of historic sediment elevations, the redirecting of freshwater streams into 

the channels that historically fed these areas, and the reopening of channels to the ocean that allow tidal 

flow into and out of the wetlands. 

The anticipated results of restoring and protecting the wetland habitats will be used to forecast the 

project’s qualitative and quantitative benefits relative to baseline IM&E losses. Projects considered for 

evaluation include several within Santa Monica Bay as well as projects in nearby Orange County. Project 

summaries are presented in order of coastwise location (upcoast to downcoast) 

3.1.1 Zuma Wetlands 

Zuma Wetlands is a small, 6-acre, freshwater marsh and creek situated about 50 miles upcoast of the 

HnGS. The wetlands have historically served as a wildlife corridor and nesting site for a variety of birds 

and small mammals. By the early 1990s periodic dumping of surplus construction and road building 

material had heavily impacted the wetlands and surrounding uplands. The existing wetlands were greatly 

reduced and, in many areas, native species were completely replaced by exotic ornamental trees, annual 

grasses, fennel, mustards, and thistles. High visitation at Zuma Beach has also impacted the site. 

Wetland restoration efforts commenced in 1998 and include the excavation of construction fill, 

recontouring of upland habitats, removal of exotic plant species, planting of more than 5,000 native 

plants, and the re-creation of an additional 21⁄2 acres of freshwater wetland/dune/riparian habitat. 

Restoration of this wetland is an ongoing process, which continues at this time. 

3.1.2 Malibu Lagoon 

Located approximately 45 miles upcoast of the HnGS, Malibu Lagoon is a coastal lagoon and salt marsh 

fed by Malibu Creek and its associate watershed. During much of the rainy season (winter and spring) the 

lagoon opens into the northern end of Santa Monica Bay. During the summer and fall, reduced flow from 

the creek and seasonal rebuilding of the beach area dams the lagoon and cuts off its connection with the 

ocean except during periods of extreme high tide and/or large ocean swells. Lacking a connection to the 

ocean the lagoon becomes a brackish water body whose salinity fluctuates with freshwater input and 

evaporation. Several habitat restoration or enhancement projects are in existence that affect the Malibu 

Creek and Lagoon directly, or indirectly, due to their influence on creeks that are tributaries of Malibu 

Creek. 

3.1.3 Topanga Lagoon and Creek 

Historically the Topanga Lagoon covered more than 30 acres, but has now been reduced to only 2 acres 

(mostly due to the deposition of 800,000 cubic feet of fill into the lagoon during the 1934 realignment of 

the Pacific Coast Highway). Located approximately 42 miles upcoast of the HnGS, 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 
Attachment B An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

5

identify ways to restore these resources. The California Department of Parks and Recreation recently 

purchased 1,659 acres of lower Topanga Canyon including the current and historic lagoon sites. 

3.1.4 Ballona Wetlands 

Located about 24 miles upcoast of the HnGS, the Ballona Wetlands contains saltwater marsh, freshwater 

marsh, coastal bluff, and dune habitats. The area, at one time, covered approximately 2,000 acres, but due 

to human encroachment and development the wetland has been greatly reduced over the last 100 years. In 

recent years, about 340 acres of the wetland has been preserved due to the efforts of numerous 

organizations that are dedicated to the preservation and restoration of the wetland. These organizations 

include Friends of Ballona Wetlands, the Ballona Wetlands Foundation, and Heal The Bay. Portions of 

the wetland include tidally influenced marsh areas that act as a nursery for Santa Monica Bay marine 

species. Restoration plans for this portion of the wetland are still being developed. Ballona is the only 

remaining large coastal wetland in Los Angeles County. 

3.1.5 Los Cerritos Wetlands 

The Los Cerritos Wetlands is located immediately adjacent to the HnGS. The wetland straddles the Los 

Angeles-Orange County border. It currently consists of about 130 wetland acres, with nearly 800 acres of 

degraded habitat proposed for restoration. Historically it consisted of about 2,400 acres and included what 

is now Alamitos Bay. Since much of the site was modified due to former oil development activities, most 

of the land was privately held. In 2006, the California Coastal Conservancy was one of several agencies 

that purchased 66 acres of the wetlands, and hopes to acquire more. The Los Cerritos Wetlands Land 

Trust of Long Beach and Seal Beach is one organization committed to restoration of the wetlands. A 

conceptual restoration plan includes full tidal restoration (inland to Westminster Avenue) via connection 

to the lower San Gabriel River. While the proximity of the Los Cerritos Wetlands to the HnGS makes it 

an attractive restoration option, other considerations associated with the project make it less than ideal. 

The recently submitted final report of the City of Long Beach, Los Cerritos Wetlands Study Group 

(available as a downloadable pdf file at http://www.longbeach.gov/plan/pb/cpd/los_cerritos.asp) cited 

several pressing issues that need to be dealt with in order to proceed with any of the proposed restoration 

projects. Two of these issues are the numerous and varied zoning and jurisdictional concerns related to 

the area of the former wetlands, and the area’s history of use as a hazardous waste disposal site. These 

concerns are reflected in the ranking of this restoration option. 

3.1.6 Bolsa Chica Lowlands 

The Bolsa Chica Lowlands Restoration Project is located about 5 miles downcoast from the HnGS 

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 11 miles downcoast from the HnGS, adjacent to the 

Huntington Beach Generating Station (HBGS). The total area of the wetlands is about 180 acres. Over the 

years, the wetlands have been divided into a number of smaller parcels by the development of the 

Huntington Beach area. The Huntington Beach Wetlands Conservancy plans to acquire the entire 180 

acres and restore it in accordance with a comprehensive wetlands restoration plan that they are currently 

preparing. Restoration will include the improvement or re-establishment of tidal circulation within the 

wetlands. This will provide additional habitat for local fish and invertebrate species. In fall 2006, AES 

Huntington Beach was required to restore 66.8 acres of the Huntington Beach Wetlands to offset 

entrainment losses for Units 3and4. 
Attachment B An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

6

3.1.8 Upper Newport Bay Ecological Reserve 

Newport Bay is located approximately 15 miles downcoast from the HnGS. The Upper Newport Bay 

Ecological Reserve was created in 1975 as result of the purchase of 527 acres of land in and around the 

bay from the Irvine Company and the transfer of 214 acres of tidal wetlands from the County of Orange 

to the State. An additional 11 acres of land in Big Canyon was added in 1982 bringing the total acreage of 

the Ecological Reserve to 752 acres. It is managed by the California Department of Fish and Game 

(CDF&G). There are currently a number of restoration projects within Upper Newport Bay. The largest is 

the dredging of 2.1 million cubic yards of sediment. The project will restore and maintain tidal movement 

within much of the Bay. Much of the dredging project still needs funding, as well as post-project 

monitoring and maintenance. Dredging will provide additional habitat for fish species already present in 

Upper Newport Bay.

3.2 COASTAL WATERSHED PROJECTS

Projects that control or reduce sediment transport into coastal wetlands may include erosion control 

projects along upland watercourses; construction of catchment basins, swales, and other sediment 

containment features; land acquisition for purposes of creating conservation easements; minimizing 

runoff from development activities; restoration of floodplain habitat; and other Best Management 

Practices. The implementation of watershed management projects as part of the restoration plan is based 

on the nexus between the loss of wetland area and its associated reduction of biologically productive 

habitat with the infilling of the wetlands by sediments eroded from its watershed. 

3.2.1 Las Virgenes Creek Restoration Project 

Las Virgenes Creek is an important tributary of Malibu Creek and Lagoon. Las Virgenes joins Malibu 

Creek approximately 5.5 miles from the coast (Malibu Lagoon). The City of Calabasas plans to remove 

over 250 linear feet of a concrete lined portion of the creek to help restore the natural flow and reduce 

sedimentation in the lower creek, and Malibu Creek and Lagoon. Stream banks will be stabilized using a 

bio-engineered revetment and replanted with native vegetation. 

3.3 PROJECTS TO ERADICATE NON-NATIVE PLANTS FROM WETLANDS

A number of projects have been proposed, or are underway, to eradicate non-native/invasive plants from 

several of the creeks that feed the wetlands along the shore of Santa Monica Bay and areas to the south. 

Plants like the Giant Reed (Arundo donax) clog waterways, increase sedimentation, and consume large 

quantities of water. Removal of these plants can help restore flow within these coastal creeks and marshes 

to historic levels. Non-native plant eradication programs are currently underway in lower Topanga Creek, 

Malibu Creek, and Solstice Creek (a tributary of Malibu Creek). 

3.4 NEARSHORE COASTAL PROJECTS

Projects for enhancing nearshore coastal areas include restoring degraded habitat such as kelp beds and 

rocky intertidal areas, and projects that establish new habitat such as the construction of artificial reefs. 

The increased biological productivity resulting from these projects can be weighed against the IM&E 

losses associated with the operation of coastal generating stations. 

3.4.1 Restoration of Natural Resources in Rocky Intertidal Habitats in 

Santa Monica Bay 

The UCLA Institute of the Environment currently has funding from the Santa Monica Bay Restoration 

Commission (as part of the Santa Monica Bay Restoration Plan) for a project to identify the causes of 

degradation of the intertidal habitats in Santa Monica Bay. The project will identify, evaluate, and 

recommend practical restoration techniques for these habitats. 
Attachment B An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

7

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 about 19 miles west of HnGS) portions of the bay were once covered by 

dense kelp forests. Over the last 50 years the acreage of these beds has been greatly reduced. Several kelp 

restoration projects, including the efforts of Santa Monica Bay Keeper, have attempted, with some 

success, to return the kelp beds to their original extent. The techniques employed include the removal of 

grazing herbivores (primarily sea urchins) and the introduction of laboratory-reared kelp plants into areas 

where kelp coverage has declined. Kelp beds provide habitat for numerous species of fish, invertebrates, 

and marine mammals. Increasing the size of the kelp beds in Santa Monica Bay or the Palos Verde 

peninsula to the west of HnGS, 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 artificial reef modules have provided new substrate for giant kelp and 

other algae. The reef and its associated kelp canopy have, in turn, provided new habitat for fish and 

invertebrates. 

3.4.4 Restocking of Affected Fish Species 

Hubbs-Seaworld Research Institute (HSWRI) operates aquaculture research facilities in southern 

California and Florida. Since 1983, the HSWRI has bred, tagged, and released over 650,000 white seabass 

into southern California waters. The institute has also bred and released other fish species, and is 

assessing the feasibility of breeding rockfish. The technology developed by the institute, as part of their 

Ocean Resources Enhancement Hatchery Program, could potentially be used to restock species, although 

the 316(b) regulations discourage a hatchery replacement approach. 

3.5 PRELIMINARY RANKING/EVALUATION OF RESTORATION PROJECTS

A set of selection criteria was developed for ranking the prospective habitat restoration projects 

previously described, or any other comparable projects that might be considered for implementation. 

They include: 

• Location • Cost effectiveness 

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

• Basic need or justification for project • Success of comparable restoration 

projects 

• Nature and extent of ecological benefits • Time before benefits accrue 

• Stakeholder acceptance • Technical feasibility 

• Administrative considerations • Opportunities for leveraging of 

funds/Availability of matching funds 

• Consistency with ongoing resource 

agency work and environmental planning 

• Legal hurdles (e.g., permits, legal 

access) 

• Implementation costs • Duration of benefits 
Attachment B An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

8

Depending upon the nature of a particular project, the relative importance and weighing of these criteria 

may vary. As a general proposition, however, projects will be selected so as to maximize the offset of 

IM&E effects for compliance with 316(b), and secondarily to optimize ecological benefits to Santa 

Monica Bay/San Pedro Bay, or adjacent offshore areas within the Southern California Bight. This 

process will ensure that the most effective projects are assigned the highest priority. 

A description of each of the criteria is provided below: 

Location

Ideally (5) the location of the project is in the same source water/ receiving water bodies that are affected 

by the operation of the facility. Scores decrease as the distance between the project area and those 

waterbodies increases. Projects that involve waterbodies and watershed areas that feed into the affected 

areas can have a high ranking but are not ideal. 

Nexus to facility’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 (5). As the project moves away from those species and locales, its 

ranking decreases. The nexus is the relationship between the environmental impacts resulting from the 

operation of the facility and the environmental benefits of the proposed project. 

Basic need or justification for project

This category requires an evaluation of the need or justification for a proposed project. Restoration 

projects that return wetland areas to their historic extent and replenish historic species that have been 

depleted may be easily justified (high score). However, if the project requires that several blocks of 

commercial property be razed to accommodate the project, it may require considerably more justification. 

Other projects, like the establishment of artificial reefs where none formerly existed, may be worthwhile 

but will require some justification for their adoption (lowered score). 

Technical feasibility

Is the technology or methodology utilized by the proposed project proven and effective? Has it, or 

something similar, been used under similar conditions? Proven track record, or pie in the sky? 

Stakeholder acceptance

Is the proposed project likely to have the support and approval of the regulatory agencies involved, the 

owners and operators of the facility, and the local citizenry? 

Nature and extent of ecological benefits

This is a category of magnitude. Does the project have a relatively narrow and limited ecological benefit, 

such as increasing the population of a single species within a limited spatial context, or does it benefit a 

large number of species (directly and indirectly) over an extensive area (higher ranking). 

Time before benefits accrue

If the proposed project is enacted, how much time will elapse before the benefits of the project become 

evident. Projects that will demonstrate their resultant benefits in a short period of time will rank higher in 

this category. However, projects that will have a large ecological benefit, but will require an extended 

period of time to come to fruition, will offset their lower ranking in this category with a higher ranking in 

the previous (nature and extent of ecological benefits) category. 
Attachment B An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

9

Duration of benefits

Projects with environmental benefits that continue over a long period of time will receive a higher ranking 

than those with short-term, transient, benefits. This category works in conjunction with the two previous 

categories. 

Success of comparable restoration projects

This category is similar to the “Technical Feasibility” category, but goes a step beyond feasibility to the 

question of the success or failure of comparable projects. High rankings to projects that are comparable to 

successful projects, low rankings to projects comparable with failed efforts, and neutral rankings to 

projects lacking comparable examples (return to the question of feasibility). 

Consistency with ongoing resource agency work and environmental planning

Does the proposed project conflict with any ongoing resource agency work or environmental planning? 

Projects without conflicts, which mesh well with ongoing projects and policy, will receive the highest 

rankings. Projects that are inconsistent with current environment policy and ongoing projects will receive 

a lower ranking (see also “Basic need or justification for project” and “Legal hurdles”). 

Legal hurdles (permitting, etc.)

In this category, projects that face significant legal hurdles, such as those that require extensive permitting 

for their implementation, will receive lower ranking than those projects not hindered by such 

requirements. The cost of overcoming these hurdles (time and money) should also be incorporated into 

the evaluation of the project in other categories (“Implementation cost”, “Time before benefits accrue”, 

and “Basic need or justification for project”). Providing additional funding for an ongoing project, that 

has already passed these hurdles, would also receive a high ranking. 

Implementation costs

This category is fairly straightforward but requires some additional information about the magnitude of 

the IM&E impacts to be offset for a proper evaluation of any potential project. The environmental 

benefits accrued by a given project need to be weighed against the impacts that need to be offset (“Cost / 

Benefit”). 

Funding opportunities (matching funds, leveraging of funds, etc.)

Ongoing projects will do well in this category since they are already receiving at least some funding. 

Many potential restoration projects have popular support which can help with additional funding as well 

as lending support in categories like “Basic need or justification for the project”, “Stake holder support”, 

and even “Legal hurdles”. Newer, more innovative, projects may have fewer funding opportunities and 

would rank lower. 

Ability to measure performance

Can the beneficial environmental effects of the proposed project be measured in some fashion that relates 

to offsetting the impacts of the operation of the facility in question? Projects with more qualitative, less 

tangible benefits would score lower in this ranking. Certain projects lend themselves more easily to this 

category than others. The restocking of an area with fish can readily be assessed by noting the number of 

fish introduced, the number surviving, the number reproducing, etc. Artificial reefs and restored kelp beds 

can be surveyed to record species recruitment and the associated increase in biomass. Restored wetlands 

may be more difficult to assess because of their complexity, including terrestrial and aquatic habitats, 

nursery areas, birds, mammals, fish, and invertebrates, transient species, etc. The performance of projects 

that restore watershed areas is even more difficult to assess because of the indirect nature of many of their 

benefits to the areas directly impacted by IM&E losses. 
Attachment B An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

10

Cost / Benefit

How much bang-for-the-buck can be hard to gauge for many projects. The cost may be relatively easy to 

calculate, but how do you measure all of the benefits of a project like the restoration of a historic wetland 

(see “Ability to measure performance”)? Ranking in this category may be somewhat 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. 

Using a five point ranking system, each of the projects described in Section 3 was scored for the criteria 

listed above. A ranking of 1 represents a very poor fit in any category; 5 an excellent fit. As an example, 

a project located in Alamitos Bay, in very close proximity to HnGS, 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 1. No rankings are provided for Implementation 

Costs or Cost Effectiveness at this time, since the magnitude and duration of the projects will be 

dependent upon the results of the LADWP IM&E studies. 

An additional aspect not considered in the criterion of ‘Opportunities for leveraging of funds/Availability 

of matching funds’ is the potential for restoration 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 generating 

facilities located in the Los Angeles/Long Beach Harbor Area and facilities further south. 

3.5.1 Results of Initial Rankings 

The results of the initial ranking of projects indicate that the larger wetlands restoration, kelp bed 

restoration and artificial reef projects would be the most suitable for further evaluation. The projects with 

the highest ranking were the Ballona Wetlands, the Bolsa Chica Lowlands, and the Huntington Beach 

Wetlands projects. Although located almost 24 miles from HnGS, the Ballona Wetlands project 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 

immediately adjacent to HnGS, did not score as high because of multiple zoning issues and the presence 

of large quantities of hazardous materials that were disposed in the area in the past. These projects, or 

other wetland projects, could be combined with one of the open coastal projects such as the establishment 

of an artificial reef to provide restoration credits for both estuarine and coastal species. 
Attachment B An Addendum To The 316(B) Evaluation Of The Hay

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

PROJECTS FOR OFFSETTING HAYNES GENERATING STATION IM&E LOSSES. 

RESTORATION PROJECT ZUMA 

WETLANDS

MALIBU 

LAGOON

TOPANGA 

LAGOON AND 

CREEK

BALLONA 

WETLANDS

LOS 

CERRITOS 

WETLANDS

BOLSA CHICA 

LOWLANDS

HUNTINGTON 

BEACH 

WETLANDS

UPPER 

NEWPORT 

BAY

LAS 

VIRGENES 

CREEK

NON-NATIVE 

PLANT 

ERADICATION

SANTA MONICA 

BAY ROCKY 

INTERTIDAL

M

EVALUATION CRITERIA

Location 4 4 4 4 5 5 5 4 3 3 5 Nexus to HnGS Impacts 4 4 4 5 4 4 4 4 3 3 3 Basic Need or Justification For Project 2 4 3 5 4 5 5 5 3 3 3 Nature and Extent of Ecological Benefits 2 3 2 5 4 4 4 4 2 2 3 Stakeholder Acceptance 5 5 5 5 5 5 5 5 5 5 5 Administrative Considerations 4 4 4 4 3 4 4 4 4 4 2 Consistency With Ongoing Resource Agency Work and Environmental Planning 5 5 5 5 5 5 5 5 5 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 

Cost Effectiveness 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 Success of Comparable Projects 3 3 3 4 4 4 4 4 3 3 2 Time Before Benefits Accrue 3 3 3 3 3 3 3 3 2 2 2 Technical Feasibility 3 3 3 4 3 4 4 4 3 3 2 Funding Opportunities(matching funds, leveraging of funds) 4 4 4 4 4 4 4 4 4 4 4 Legal Hurdles (permitting, etc.) 4 4 4 4 3 4 4 4 4 4 3 Duration of Benefits 3 3 3 5 5 5 5 5 3 3 3 

TOTAL 49 52 50 61 56 60 60 59 46 46 43 
Attachment B An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

12

4.0 CONCLUSIONS AND RECOMMENDATIONS 

An initial screening of potential projects in the vicinity of the LADWP power plants using the set of 

criteria described in this report was used to determine that wetlands restoration, kelp bed restoration and 

artificial reef projects would be the most suitable for further evaluation. Restoration projects associated 

with the Ballona Wetlands, Bolsa Chica Lowlands and Huntington Beach Wetlands received the highest 

rankings using the criteria previously described. Although located almost 24 miles upcoast of HnGS, the 

Ballona Wetlands scored highly because they are located only 4 miles upcoast from the another LADWP 

facility, SGS, and they are the only remaining large coastal wetlands in Los Angeles County. There are 

active groups involved with the preservation of the wetlands and acquisition of additional lands to expand 

the wetlands to its historical boundaries. These groups and projects associated with the Ballona Wetlands 

provide opportunities for funding similar to the approach used at Elkhorn Slough for the Moss Landing 

Power Plant where money was transferred to the Elkhorn Slough Foundation for the expansion and 

preservation of wetland habitat that offset entrainment losses from the power plant. 

The proposed restoration of the Los Cerritos Wetlands adjacent to the HnGS, has the potential to be a 

viable restoration option for any or all of the LADWP facilities. However, as cited in the final report of 

the City of Long Beach, Los Cerritos Wetlands Study Group (available as a downloadable pdf file at 

http://www.longbeach.gov/plan/pb/cpd/los_cerritos.asp), there are several pressing issues that need to be 

dealt with prior to proceeding with any of the proposed restoration projects. These issues include the 

numerous and varied zoning and jurisdictional concerns related to the area of the former wetlands, and the 

area’s history of use as 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 San Onofre 

Nuclear Generating Station (SONGS) is using an artificial reef as mitigation for the effects of the thermal 

discharge on kelp beds and associated communities. Studies at a pilot scale artificial reef being used in the 

design of the final full-scale project show that the artificial reef is performing similar to natural reefs in 

the area. Development of giant kelp (Macrocystis spp.) on an artificial reef would provide the added 

benefit of increasing the area of kelp habitat, an important habitat-forming community in the nearshore 

areas at the north and south headlands of Santa Monica Bay. Kelp beds provide habitat for a wide variety 

of invertebrates and fishes. An artificial reef project in Santa Monica Bay benefits from all of the work 

that has been completed for the SONGS reef project. It is also relatively easy to demonstrate the benefits 

from an artificial reef, since the SONGS project has shown that communities develop fairly rapidly on the 

new habitat. 
Attachment C An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

13

ATTACHMENT C - 

FLOW CALCULATIONS 

The following is a summary of HnGS flow calculations. 

Data: 

Flow (Q): 1,497 cfs (Units 1,2,5,6 and 8) 

Water Elevation (Mean Low Water): El. -2.7 feet 

Number of Trash Rack Openings: 7 (only 6 in use) 

Area of Each Intake Opening: 175.0 feet2 (3.5 feet by 50 feet openings) 

Number of Intake Pipes: 7 (only 6 in use) 

Area of Each Intake Pipe: 50.3 feet2 (8 feet diameter pipes) 

Invert of Intake Canal: El. -19.0 feet 

Bottom Width of Intake Canal: 30.0 feet 

Side Slope: 2.5 H to 1 V 

Formulas Used 

Calculations 
Attachment D An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

1

ATTACHMENT D - 

FISH MORPHPMETRY AND SCREEN MESH HEADLOSS 

The following information on fish morphometry was developed by LMS as part of a NJPDES Permit 

special condition for PSEG Services Corporation’s Salem Generating Station6. 

This study was designed to use physical measurements from preserved ichthyoplankton to compute the 

expected size of larval fish retained by plankton nets of various mesh sizes. “...Expectations of the size of 

organisms to be retained by a given mesh size can be developed from the physical dimensions of the 

organism. This may be done by first relating the greatest cross-sectional dimension (such as skull width or 

other measures of body girth) to overall fish length. Then, the greatest mesh dimension is computed, 

typically the mesh diagonal. Smith et al. (1968) found that the maximum cross-sectional diameter of the 

organism must be greater than the mesh diagonal if it is to be fully retained. For a given cross-sectional 

diameter and associated standard deviation, the percentage retained and excluded is calculated by 

integration under a normal curve. Examples of this type of analysis may be seen in Vannucci (1968), 

Lenarz (1972), Colton et al. (1980), Turnpenny (1981), Schneeberger and Jude (1981) among others. 

Results of this analysis may then be used to develop working guidelines for the minimum size necessary 

for retention of each species....” The only exception is the data for naked goby which were developed 

from scale-drawings by Alden using the LMS model. The reported entrainment and impingement 

probabilities are for 0.5 mm mesh screens and are provided as an illustration of the effect of length/HCD 

on entrainment and impingement. The reported HCD at body length was used to predict the HCD for 

HnGS species. The series 3 and 4 categories refer to entrainment and impingement, respectively. 

The screen mesh/headloss assessment was prepared by Alden with data provided by Johnson Screens and 

Siemens Screens. 

 

6

 Public Service Enterprise Group. (2002). Salem Generating Station, NJPDES Permit #NJ0005622, 

Custom Requirement G.9.b.ii, Entrainment Extrusion Study, Task #1, Morphometric Analysis. 
Attachment D An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

2

Atlantic Silverside

Eggs: 

 

Probability Probability 

Entrainment Impingement 

0.00000000 1.00000000 

 

Larvae 

length ln(length) ln(HCD) HCD Probability Probability 

(mm) (mm) Entrainment Impingement

 

1 0 -2.17238 0.113907 1 0

2 0.6931472 -1.47022 0.229876 1 1.9867E-12

3 1.0986123 -1.05948 0.346636 0.99946385 0.00053615

4 1.3862944 -0.76806 0.463913 0.74820565 0.25179435

5 1.6094379 -0.54201 0.581576 0.08860428 0.91139572

6 1.7917595 -0.35732 0.699547 0.00135686 0.99864314

7 1.9459101 -0.20117 0.817775 5.5983E-06 0.9999944

8 2.0794415 -0.0659 0.936224 1.0692E-08 0.99999999

9 2.1972246 0.053413 1.054866 1.3169E-11 1

10 2.3025851 0.160144 1.17368 1.2815E-14 1

11 2.3978953 0.256693 1.292648 1.1191E-17 1
Attachment D An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

3

Atlantic croaker

Eggs: 

 

Probability Probability 

Entrainment Impingement 

0.00354797 0.99645203 

 

Larvae 

length ln(length) ln(HCD) HCD Probability Probability 

(mm) (mm) Entrainment Impingement

 

1 0 -1.9015 0.149345 1 0

2 0.6931472 -1.1023 0.332107 1 4.5773E-12

3 1.0986123 -0.6348 0.530043 0.16540446 0.83459554

4 1.3862944 -0.3031 0.738525 3.9953E-11 1

 
Attachment D An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

4

Bay anchovy

Eggs: 

 

Probability Probability 

Entrainment Impingement 

0.00007334 0.99992666 

 

Larvae 

length ln(length) ln(HCD) HCD Probability Probability 

(mm) (mm) Entrainment Impingement

 

1 0 -1.69755 0.183132 1 3.5926E-10

2 0.6931472 -1.2165 0.296265 0.99933809 0.00066191

3 1.0986123 -0.93511 0.392543 0.9311524 0.0688476

4 1.3862944 -0.73546 0.479286 0.60240373 0.39759627

5 1.6094379 -0.5806 0.559565 0.24494069 0.75505931

6 1.7917595 -0.45406 0.635041 0.07122037 0.92877963

7 1.9459101 -0.34708 0.706746 0.01687337 0.98312663

8 2.0794415 -0.25441 0.775371 0.00355533 0.99644467

9 2.1972246 -0.17267 0.841413 0.00070377 0.99929623

10 2.3025851 -0.09955 0.905243 0.00013543 0.99986457

11 2.3978953 -0.03341 0.967145 2.5885E-05 0.99997411

12 2.4849066 0.026979 1.027346 4.982E-06 0.99999502

13 2.5649494 0.152558 1.16481 1.0607E-07 0.99999989

14 2.6390573 0.281506 1.325124 1.1194E-09 1

15 2.7080502 0.401553 1.494144 9.342E-12 1

16 2.7725887 0.51385 1.671716 6.5628E-14 1

17 2.8332133 0.619337 1.857696 4.0709E-16 1

18 2.8903718 0.718793 2.051955 2.3135E-18 1
Attachment D An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

5

Atlantic menhaden

Eggs: 

 

Probability Probability 

Entrainment Impingement 

0.00000000 1.00000000 

 

Larvae 

length ln(length) ln(HCD) HCD Probability Probability 

(mm) (mm) Entrainment Impingement

 

1 0 -0.46918 0.625518 0.03208407 0.96791593

2 0.6931472 -0.18776 0.828816 1.4783E-05 0.99998522

3 1.0986123 -0.02314 0.977127 1.5362E-08 0.99999998

4 1.3862944 0.093661 1.098187 3.9487E-11 1

5 1.6094379 0.184257 1.202325 2.0644E-13 1

6 1.7917595 0.258279 1.2947 1.8748E-15 1

7 1.9459101 0.320865 1.378319 2.6405E-17 1
Attachment D An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

6

Naked goby

Eggs: 

 

Probability Probability 

Entrainment Impingement 

0.00000000 1.00000000 

 

Larvae 

length ln(length) ln(HCD) HCD Probability Probability 

(mm) (mm) Entrainment Impingement

 

1 0 -1.40758 0.244734 1 1.5477E-13

2 0.6931472 -0.82465 0.43839 0.9101756 0.0898244

3 1.0986123 -0.48365 0.616528 0.01626992 0.98373008

4 1.3862944 -0.24171 0.785284 2.0475E-06 0.99999795

5 1.6094379 -0.05405 0.947388 3.4819E-11 1

6 1.7917595 0.099286 1.104382 3.0815E-16 1

7 1.9459101 0.228926 1.25725 2.5064E-21 1

 
Attachment D An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

7

Wire-mesh screen head loss characteristics

Assumptions for head loss calculations: 

Screen approach velocity at 1 feet/sec 

Through-flow screen (two screen mesh baskets in flow path) 

Head loss coefficients from M. Papworth 1972 

Screen characteristics: 

Screen 

Mesh 

Wire 

spacing 

(in) 

Wire 

dia. 

(in) 

Wire 

dia. 

(mm) 

opening 

(mm) 

Open 

area 

Backup 

screen 

(1" 

mesh) 

combined 

open area 

with 1" backup screen 

3/8" mesh 0.444 0.08 2.0 9.3 67% no 67% 

10 mesh 0.100 0.025 0.64 1.9 56% yes 45% 

18 mesh 0.056 0.017 0.43 1.0 48% yes 39% 

30 mesh 0.033 0.012 0.30 0.5 41% yes 33% 

50 mesh 0.020 0.009 0.23 0.3 30% yes 24% 

70 mesh 0.014 0.0065 0.17 0.2 30% yes 24% 
Attachment D An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

8

LITERATURE CITED

Colton, J.B., Jr., J.R. Green, R.R. Byron, and J.L. Frisella. 1980. Bongo net retention rates as effected 

by towing speed and mesh size. Can. J. Fish. Aquat. Sci. 37:606-623. 

Lenarz, W.H. 1972. Mesh retention of Sardinops caerulea and Engraulis mordax by plankton nets. Fish. 

Bull. U.S. 70:839-848. 

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

capabilities of small-mesh screens at cooling-water intakes. Trans. Amer. Fish. Soc. 110:246-252. 

Smith, P.E., R.C. Counts, and R.I. Clutter. 1968. Changes in filtering efficiency of plankton nets due to 

clogging under tow. J. Cons. perm. int. Explor. Mer.32: 232-248. 

Turnpenny, A.W.H. 1981. An analysis of mesh sizes required for screening fishes at water intakes. 

Estuaries, 4(4):363-368. 

Vannucci, M. 1968. Loss of organisms through the meshes. In D.J. Tranter (ed.), Part I, Review on 

zooplankton sampling methods, p. 77-86. UNESCO Monograph. Oceanography. Methodology. 2, 

Zooplankton Sampling 
Attachment E An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

1

ATTACHMENT E - 

POTENTIAL FISH RETURN CLEANING SYSTEMS 

Fish and debris removed from either coarse- or fine-mesh traveling water screens would have to be 

conveyed back to the ocean outside of Long Beach Harbor through a 12,000 feet long return pipe. This 

return location was selected as returning fish to the discharge canal is expected to increase mortality due 

to thermal stress. Once removed from the screens, fish and debris would flow into an open trough that 

would run the length of the intake canal from Unit 6 through Unit 1. Water would need to be added to the 

trough upstream Unit 6 to provide the fish removed from the Unit 6 screens a 6 inch water cushion. 

Downstream of the Unit 1 screens, the return trough would flow into a small sump where a fish-friendly 

pump would provide the head required to create a 4 feet/sec velocity in the return pipe. The return pipe 

would be a 1.5 feet diameter smooth-walled pipe. A closed pipe was selected to prevent predation from 

birds and other animals and allow the pipe to be placed on grade. Within the tidal area, the pipe would 

transition back into an open trough to allow, a smooth transition back to the ocean while allowing access 

to the portion of the return that cannot be isolated. 

Cleaning 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 One of the existing discharge

lines would need to be tapped. A 

pump would be required to 

transport water back to the 

intake. 

Twice as much pipe with isolation 

valves. 

Construction Impacts on Plant 

Operation 

Would require a unit to be 

shutdown while the discharge is 

tapped. Could be completed 

during a scheduled outage. 

None. 

Impacts on Plant Operation Heat treatments would need to 

be timed to coincide when units 

are operating at maximum inlet 

temperature and plant output. 

None. 

Impacts on Screen Operation None. None. 

Impacts on Survival No survival during heat 

treatment. 

None. 

Reliability If return pipe or hot water line 

fails there is no redundancy. 

If one return pipe fails the second 

one can be brought into 

operation rapidly. 

Installation Cost1 $2,480,000 $3,625,000 

O&M Costs1 $35,000 $35,000 

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 the fish return required for Modular Included Screens. The fish return pipe for the MIS 

would be about half the length of the traveling screen return but would require a larger pipe, about 4 feet 

diameter, 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 as the 

length of the heat treat pipe would be about the same length as the second return pipe. 
Attachment F An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

1

ATTACHMENT F - 

NARROW-SLOT, WEDGEWIRE SCREEN CONCEPTUAL DESIGN 

Narrow-slot wedgewire screens could be installed in the intake canal at HnGS. To function effectively, 

an “ambient” flow past the screens would be needed to remove impinged fish and debris from the screens. 

To create this ambient flow, “fish friendly” bypass pumps located at the terminus of the canal would be 

used. The following discussion relates to existing conditions and does not take into account the Units 5 

and 6 re-powering potentials. 

Conceptual Design

The screens would be installed on a bulkhead wall located in the existing intake canal as shown on Figure 

F-1. The bulkhead would partition off about half of the intake canal, extending from approximately 150 

feet upstream of the Unit 1 CWIS to the terminus of the canal. This partition would isolate the flow 

through the wedgewire screens from the flow heading to the bypass pumps. The bulkhead would consist 

of sheetpile walls, steel support piles, and a 12 feet wide platform extending the length of the bulkhead. 

The top of the bulkhead wall and platform would be at El. 8.0 feet. A new pumphouse would be 

constructed for the pumps that would provide the ambient flow past the screens. 

The screens would have a 0.5 mm slot size and would be designed for a maximum slot velocity of 0.5 

feet/sec. A narrower slot size was not evaluated as 0.5 mm is the finest slot size currently available for 

cylindrical wedgewire screens at cooling water intake structures. Fifty-six T-84 screens would be 

required for total plant flow, a breakdown of the number of screens required be unit is provided in Table 

F-1. Each screen would be 7.0 feet in diameter and T-shaped, with an overall length of about 23.0 feet. 

Two screen sections, each about 8.0 feet long, would be located on each side of a 7.0 feet long T section. 

The outlet pipe would be 5.0 feet in diameter and located in the middle of the T section. The outlet of the 

T would be flanged for connection to a 5.0 feet diameter intake pipe. The screens would be installed in 

two rows. The centerline of the rows will be 21.0 feet apart, providing two diameters of clear spacing 

between screens. A sectional view of the screens in the intake canal is shown in Figure F-2. The 

upstream end of the screen cylinders would be tapered to deflect submerged floating debris. A typical 

section of a wedge wire screen is shown on Figure F-3. 

Currently, the flow in the intake canal is a result if the circulating water withdrawal. This flow does 

create a bypass flow for the upstream-most units; however, the fish and debris that bypass these units 

would be impinged or entrained through the latter units. To remedy this, additional flow needs to be 

added to the intake canal. A minimum bypass velocity of about 1.0 feet/sec at the last screen is 

recommended by Alden to transport fish and debris from the screens. To reduce the amount of bypass 

flow needed a second bulkhead wall would be installed along the south side of the intake canal. This wall 

will be angled into the canal to decrease the cross-sectional area. A bypass flow of about 700 cfs would 

be needed to create a 1.0 feet/sec velocity at the end of the canal. This flow will be created by (6) 450 hp, 

Hidrostal pumps located in a small intake located at the terminus of the intake canal. Hidrostal pumps use 

a fish friendly screw impellor that can pump fish and debris without causing damage, typically associated 

with pumps. To prevent large debris from damaging the pumps a trash rack would be installed at the face 

of the structure. This bypass flow would allow use of an air backwash system to remove debris from the 

screens. The air backwash system would be fully automated, and include all necessary air compressors 

and controls. Air compressors, air receivers and controls would be located in a new pump house or near 

the new bulkhead. Air piping for each wedgewire screen would be installed under the platform walkway 

and run along the top of the intake pipes to each screen. In addition to the air backwash, periodic manual 

cleaning for removal of biofouling may be necessary. 

After passing through the bypass pumps, fish and debris will be conveyed through a 12.0 feet diameter 

discharge pipe to either the San Gabriel River (plant-side) or directly back to the ocean. The velocity 

within the pipe would be about 6.2 feet/sec which should be sufficient to prevent large organisms from 

holding within the pipe. Fouling in the return pipe could be an issue. To reduce the potential for fouling, 
Attachment F An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

2

the walls of the pipe would be treated with an anti-fouling epoxy coating. A return pipe to the San 

Gabriel River would be about 1,000 feet long. Discharging to the San Gabriel River may result in the 

increased mortality due to increased thermal stress, as the river is used by both HnGS and Alamitos as a 

discharge canal. 

Engineering Considerations

Approach velocities at the wedgewire screens would be 1.0 feet/sec or greater at normal water levels (El. 

0.0 feet) and full plant operations. The estimated velocities in the canal under these conditions are 

provided in Table F-2. The velocities in the canal during both low and high water are also provided in 

this table. When the water in the canal is high, the velocity approaching the last screen would be about 

0.9 feet/sec which should be sufficient to transport debris away from the screens. Assuming fairly 

uniform flow through each screen, the maximum through-screen velocity would not exceed 0.5 feet/sec. 

Headloss through the screens should not exceed one foot (assuming biofouling would not be a significant 

problem). Except for the slightly lower water level, flow characteristics between the bulkhead and 

CWISs with the wedgewire screens would not be any different than the existing intake. Flow patterns to 

the pumps would not change from the existing conditions. 

Installing wedgewire screens in this manner is atypical and would require hydraulic model studies 

(numeric and/or physical) to determine the optimum layout of the screens and the effectiveness of the 

sweeping current. Cost for these studies have not been included but could range from about $20,000 for a 

simple two-dimensional numeric study up to about $200,000 for both three-dimensional numeric and 

physical models. 

Construction Considerations

Installation of the new wedgewire units and modifications to the existing intake structure would be 

accomplished over a two-year period and would be sequenced to minimize impacts on plant operation. 

The bulkhead wall and platform would be installed first. The upstream end of the bulkhead and all the 

intake pipe openings would remain open to allow continued plant operation. Construction of the fish 

return pipe would occur simultaneously to the bulkhead installation since two years would be needed to 

complete if the return pipe back to the ocean. After completion of the bulkhead walls, a cofferdam would 

be constructed just upstream of the terminus of the canal to allow the bypass structure to be constructed 

for the bypass pumps. The air-burst control systems and piping would also be installed at this time. Once 

the bypass pumps and return system are operational, the wedgewire screens, cleaning system and 

remaining bulkhead walls would be installed. During this stage, which is expected to take about 2 

months, the facility would need to be shutdown. 

Operation and Maintenance Considerations

Operation and maintenance (O&M) of the screens would eliminate operation and maintenance on the 

existing traveling water screens. Maintenance requirements for the circulating water pumps with the 

wedgewire screens in place would not change. An air-burst system would be used to clean the screens. 

For this evaluation, Alden assumes that the screens would need to be cleaned three times a day; the actual 

number will vary depending on the debris loading in the canal. Five, 150-hp air compressors operating 9 

hours a day would be necessary to air-burst the screens. Operating the air compressors would require 

1,848,000 kWh per year and about 1,095 man-hours per year to monitor backwashing operation and to 

maintain the air supply equipment. In addition, the screens would require a bi-annual inspection to 

identify any damage that could affect plant operations and to verify effective cleaning by the air backwash 

system. During the inspection, each screen would be manually cleaned, if necessary. Each inspection 

and cleaning would take approximately one week using divers working in the canal. 

The fish bypass system would require extensive O&M effort. Each bypass pump would require a 450 Hp 

motor and need 16,281,000 kWh per year to operate. Additionally, about 1 hour per day would be needed 

to remove any debris from the bypass pump trash racks and to inspect the pumps. The total O&M 
Attachment F An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

3

associated with the wedgewire system in the canal would require about 18,129 MWh per year and 1,880 

man-hours. Depending on the return system selected, the man-hours required to clean the pipes would be 

about 484 hours for the 1,000 feet long pipe up to 6,084 for the 15,000 feet long pipe. Energy 

requirements to clean either return pipe would be negligible; however, HnGS would need to be shutdown 

during the cleaning to allow the pipe to be de-watered. 

Costs 

Order-of-magnitude project costs were developed for this alternative. The costs for the two potential 

return pipes are included as separate items. The costs were estimated using quantities developed from the 

conceptual design and cost data from other projects that were adjusted for identifiable differences in 

project sizes and operations. These costs allow LADWP to compare the costs for this option with that of 

other potential compliance options at HnGS. 

The estimated costs are based on the following: 

• Present-day prices and fully contracted labor rates as of January 1, 2007. 

• Forty-hour work week with single-shift operation for construction activities that do not impact 

plant operations and fifty-hour work week with double-shift operation for construction activities 

that impact plant operations. 

• Direct costs for material and labor required for construction of all project features. The direct 

costs also include distributable costs for site non-manual supervision, temporary facilities, 

equipment rental, and support services incurred during construction. These costs have been taken 

as 85% of the labor portion of the direct costs for each alternative. 

• Indirect costs for labor and related expenses for engineering services to prepare drawings, 

specifications, and design documents. The indirect costs have been taken as 10% of the direct 

costs for each alternative. 

• Allowance for indeterminates to cover uncertainties in design and construction at this preliminary 

stage of study. An allowance for indeterminates is a judgment factor that is added to estimated 

figures to complete the final cost estimate, while still allowing for other uncertainties in the data 

used in developing these estimates. The allowance for indeterminates has been taken as 10% of 

the direct, distributable, and indirect costs of each alternative.

• Contingency factor to account for possible additional costs that might develop but cannot be 

predetermined (e.g., labor difficulties, delivery delays, weather). The contingency factor has been 

taken as 15% of the direct, distributable, indirect, and allowance for indeterminate costs of each 

concept. 

• Replacement power costs 

The project costs do not include the following items that should be included to obtain total capital cost 

estimates: 

• Costs to perform additional laboratory or field studies that may be required, such as hydraulic 

model studies, biological evaluations of prototype fish protection systems, soil sampling, and 

wetlands delineation and mitigation. 

• Costs to dispose of any hazardous or non-hazardous materials that may be encountered during 

excavation and dredging activities. 

• LADWP costs for administration of project contracts and for engineering and construction 

management. 

• Price escalation 
Attachment F An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

4

• Permitting costs 

The estimated project costs for the wedgewire screens and the two return options are presented in Table 

F-3 through Table F-5. 

The annualized costs associated with each of the return options are presented in Table F-6. To annualize 

the costs, several assumptions were made: 

• The capital costs were annualized over 10 years 

• A 7% discount rate was used 

• The cost per MWh is $50.00 

Alden included an estimate of existing annual O&M costs to allow incremental costs to be calculated. 

The exiting O&M costs were estimated using the same assumptions as used in calculating the O&M costs 

for the selected technologies. Incremental costs provide a better estimate of the additional cost that would 

be required. 

The cost for wedgewire screens with either of the return systems can be calculated by adding the costs of 

wedgewire to the return costs. The incremental annual cost for wedgewire screens is $17,521,000 for the 

1,000 feet long return and $ 32,529,000 for the 15,000 feet long return. 
Attachment F An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

5

FIGURE F-1. LAYOUT OF CYLINDRICAL WEDGEWIRE SCREENS IN THE INTAKE CANAL
Attachment F An Addendum To The 316(B) Evaluation Of The Hay

6

FIGURE F-2. SECTION OF CYLINDRICAL WEDGEWIRE SCREENS IN THE INTAKE CANAL
Attachment F An Addendum To The 316(B) Evaluation Of The Hay

7

FIGURE F-3. TYPICAL WEDGEWIRE SCREEN AT HNGS 
Attachment F An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

8

TABLE F-1. NUMBER OF CYLINDRICAL WEDGEWIRE SCREENS REQUIRED FOR EACH UNIT

Intake T-84 Screens Needed 

Unit 1 8 

Unit 2 8 

Unit 8a 7 

Unit 8b 7 

Unit 5 13 

Unit 6 13 

Total 56 

TABLE F-2. VELOCITIES IN THE INTAKE CANAL WITH THE FISH BYPASS SYSTEM AT DIFFERENT 

WATER LEVELS. 

Location Flow (cfs) 

Extreme Low 

Water (El. -

6.0 feet) 

 Mean Low 

Water (El. -

2.7 feet) 

MSL (El. 0.0 

feet) 

High Water 

(El. 3.0 feet) 

Upstream of Intakes 2197.2 3.3 2.4 2.0 1.6

less 1 1983.3 3.0 2.2 1.8 1.4

less 2 1769.4 2.7 2.0 1.6 1.3

less 8a 1591.2 2.4 1.8 1.4 1.2

less 8b 1413.0 2.1 1.6 1.3 1.0

less 5 1056.5 2.3 1.9 1.6 1.4

less 6 700.0 1.5 1.2 1.1 0.9

Bypass only1 700.0 1.05 0.8 0.6 0.5

1. Just upstream of Unit 1 with only the bypass pumps in operation. 
Attachment F An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

9

TABLE F-3. ESTIMATED COSTS FOR 0.5 MM WEDGEWIRE SCREENS

Item Estimated Cost 

Direct Costs 

Mobilization and Demobilization $2,569,000 

Bulkhead Wall $4,027,000 

Bulkhead Deck $4,468,000 

Intake pipes & supports $643,000 

Wedgewire Screens $3,902,000 

Bypass intake $434,000 

Bypass Pumps and Pipes $3,520,000 

Air-burst Cleaning System $2,000,000 

Cranes, Barges and Equipment $6,691,000 

 

Direct Costs (2007 $) $28,254,000 

 

Indirect Costs 2,825,000

 

Subtotal $31,079,000 

 

Allowance for Indeterminates/Contingencies 7,770,000

 

Total Estimated Project Costs (2007 $) $38,849,000 

Impacts on Plant Operation 

Item Impact 

Construction 

 

Duration (months) 24 

Outage (months) 2 

 

 

Incremental Annual Operation and Maintenance 

Labor, (hrs) 1,880 

Component Replacement $65,000 

Energy (kwh) 18,129,000 

Peak Power (kw) 2,138 
Attachment F An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

10

TABLE F-4. ESTIMATED COSTS A 1,000 FEET RETURN PIPE

Item Estimated Cost 

Direct Costs 

Mobilization and Demobilization $254,000 

Discharge Pipe $2,184,000 

Discharge Structure $341,000 

Isolation gate $16,000 

Barges, Divers and Equipment $0 

 

Direct Costs (2007 $) $2,795,000 

 

Indirect Costs $279,500

 

Subtotal $3,075,000 

 

Allowance for Indeterminates/Contingencies $769,000

 

Total Estimated Project Costs (2007 $) $3,844,000 

Impacts on Plant Operation 

Item Impact 

Construction 

 

Duration (months) 6 

Outage (months) 0 

 

 

Incremental Annual Operation and Maintenance 

Labor, (hrs) 484 

Component Replacement $0 

Energy (kwh)1147,000 

Peak Power (kw) 0 

1. Energy is replacement power needed when the facility is shutdown to 

clean the discharge pipe 
Attachment F An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

11

TABLE F-5. ESTIMATED COSTS FOR A 15,000 FEET RETURN PIPE

Item Estimated Cost 

Direct Costs 

Mobilization and Demobilization $3,311,000 

Discharge Pipe $32,755,000 

Discharge Structure $341,000 

Isolation gate $16,000 

Barges, Divers and Equipment $0 

 

Direct Costs (2007 $) $36,423,000 

 

Indirect Costs $3,642,300

 

Subtotal $40,065,000 

 

Allowance for Indeterminates/Contingencies $10,016,000

 

Total Estimated Project Costs (2007 $) $50,081,000 

Impacts on Plant Operation 

Item Impact 

Construction 

 

Duration (months) 24 

Outage (months) 0 

 

 

Incremental Annual Operation and Maintenance 

Labor, (hrs) 6,084 

Component Replacement $0 

Energy (kwh)1311,000 

Peak Power (kw) 0 

1. Energy is replacement power needed when the facility is shutdown to 

clean the discharge pipe 
Attachment F An Addendum To The 316(B) Evaluation Of The Haynes Generating Station

12

TABLE F-6. COST COMPARISON OF EVALUATED ALTERNATIVES

Capital Costs Annual O&M Costs 

Alternative Total Project 

Construction

Costs 

(2007$) 

Replacement 

Power During

Construction 

(MWh) 

Total Capital

Costs 

(2007 $)1

Energy 

(2007 $)1 

Labor 

(2007 $) 

Component 

Replacement

(2007 $) 

Narrow slot Wedge

Wire Screens 

and bypass 

structure, without 

a return system 

$38,849,000 489,000 $63,299,000 $906,000 $101,000 $65,000 

1,000 feet long 

Return Pipe $3,844,000 0 $3,844,000 $7,342,000 $16,000 $0 

15,000 feet long 

Return Pipe $50,081,000 0 $50,081,000 $15,541,000 $242,000 $0 

Existing 

Operations3 $0 0 0 $8,000 $175,000 $285,000 

Annualized Costs Incremental Costs 

Alternative 

Total Annual 

O&M 

Annualized 

Capital Costs 

(2007 $)2

Total 

Annualized 

Costs 

(2007 $)

Incremental 

O&M 

Incremental 

Annualized Costs 

(2007 $) 

Narrow slot Wedge

Wire Screens $1,072,000 $9,012,000 $10,084,000 $604,000 $9,616,000 

1,000 feet long 

Return Pipe $7,358,000 $547,000 $7,905,000 $7,358,000 $7,905,000 

15,000 feet long 

Return Pipe $15,783,000 $7,130,000 $22,913,000 $15,783,000 $22,913,000 

Existing Operations $468,000 $0 $468,000 $0 $0 

1. Assumed $50 per MWh. 

2. Annualized over 10 years with a 7% Discount rate 

3. Estimated by Alden