EVALUATION OF THE HARBOR GENERATING STATION 

WITH RESPECT TO THE ENVIRONMENTAL PROTECTION AGENCY’S 316(b) 

RULES FOR EXISTING FACILITIES 

Prepared by 

Alden Research Laboratory, Inc.: 

Nathaniel Olken, Civil Engineer 

Jonathan L. Black, Biologist 

Thomas C. Cook, Director, Environmental Engineering 

Electric Power Research Institute: 

Douglas A. Dixon, Manager, Fish Protection Program 

for 

Los Angeles Department of Water and Power 

334-04/E400F December 2004 

EVALUATION OF THE HARBOR GENERATING STATION 

WITH RESPECT TO THE ENVIRONMENTAL PROTECTION AGENCY’S 316(b) 

RULES FOR EXISTING FACILITIES 

Prepared by 

Alden Research Laboratory, Inc.: 

Nathaniel Olken, Civil Engineer 

Jonathan L. Black, Biologist 

Thomas C. Cook, Director, Environmental Engineering 

Electric Power Research Institute: 

Douglas A. Dixon, Manager, Fish Protection Program 

for 

Los Angeles Department of Water and Power 

December 2004 

ALDEN RESEARCH LABORATORY, INC. 

ENVIRONMENTAL SERVICES 

30 Shrewsbury Street 

Holden, MA 01520 

ES-1 

EXECUTIVE SUMMARY 

The U.S. Environmental Protection Agency (EPA) has promulgated guidelines for the 

implementation of section 316(b) of the Clean Water Act (CWA) for Phase II Existing Facilities 

(the Rule). The Rule uses national performance standards (reduction in impingement mortality 

of 80-95% and, in some cases, a reduction in entrainment of 60-90%, compared to a baseline), as 

a metric for measuring the effectiveness of compliance options. 

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

(collectively referred to as “The Team”) have assessed which alternative technologies, 

operational measures, and/or restoration measures are likely to meet the performance standards, 

and the monetary impact associated with both the implementation and operation of the identified 

alternatives and the permitting and monitoring associated with compliance. Based on this review 

of the Rule and the available data, Los Angeles Department of Water and Power’s (LADWP) 

Harbor Generating Station’s (Harbor) cooling water intake structure (CWIS) may be in 

compliance with the Rule. If CalEPA does not believe that Harbor is already in compliance or 

proposes more stringent standards then LADWP may need to implement changes in the design 

and/or operation of the CWIS. 

EPA will require Harbor Unit 5 to meet both the impingement mortality and entrainment 

reduction (IM&E) standards because it withdraws water from a tidal embayment and has a 

capacity utilization rates greater than 15% (Units 1, 2 & 5). No other units at Harbor use 

circulating water and should therefore already be in compliance with the Rule. 

The Team believes the current configuration of Harbor’s CWIS along with the existing flow 

reductions may meet the performance standards. Since California EPA (CalEPA) can require 

LADWP to meet more stringent standard, LADWP should review technological, operational, 

and/or restoration measures that have the potential to reduce IM&E. Since Harbor’s existing 

National Pollution Discharge Elimination System (NPDES) permit expires June 30, 2008, less 

than 4 years after the Rule was published in the Federal Register, LADWP should apply for an 

extended permitting application schedule. LADWP should also begin gathering the information 

EPA requires for the permit application. 

Technological and operational options that have potential to meet the performance standards and 

are practicable for installation at Harbor were identified. Selected options were developed to 

allow preliminary cost estimates to be generated. These cost estimates take into account sitespecific factors that potentially increase or decrease installation and operating and maintenance 

(O&M) costs at Harbor. In addition, the costs developed in this report were compared to the cost 

EPA used in developing the National Costs for the Rule. 

Some key findings of our preliminary analysis include: 

• The design and operation of Units 1&2, 5 and 10-14 may provide Harbor with an 84% 

reduction in flow from a theoretical baseline if all eight units were designed and operated 

as once-through units. If only Units 1, 2, & 5 are considered, then the existing operations 
ES-2 

would result in a flow reduction of 68%. Because flow and entrainment are directly 

proportional (assuming equal distribution of organisms), this flow reduction should 

reduce entrainment by greater than the 60% required by the Rule. 

• The existing through-screen velocity at the traveling water screens is less than 0.5 ft/sec 

during normal plant operations. Harbor should automatically meet the IM reduction 

standard via Compliance Alternative 1due to this low velocity. 

• Two technological (fine-mesh Ristroph screens and narrow-slot wedgewire screens) and 

two operational options (existing operations and closed-cycle cooling) were considered to 

have potential for meeting the impingement mortality and entrainment reduction 

standards and were deemed practicable from an engineering standpoint. As the existing 

CWIS should already meet the IM reduction standard, technologies that reduce only IM 

were not evaluated. 

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

the annualized costs range from $0 for to maintain current operations to $3,206,000 for 

closed-cycle cooling. 

• If the existing operations at Harbor do not meet the IM&E standard, replacing the 

existing screens with fine-mesh Ristroph screens or narrow-slot wedge wire screens have 

the greatest potential to meet the standards. The annualized costs for these technologies 

are $486,000 for fine-mesh Ristroph screen and $470,000 for narrow-slot wedge wire 

screens. 

• In Appendix A of the Rule, EPA provided an annualized cost of $62,942, for Harbor to 

upgrade its CWISs with a fish protection technology (EPA 2004a). This cost was for 

meeting only the IM reduction standard by the addition of fish handling and return 

system to an existing traveling screen system. Since the Team believes that Harbor will 

be required to meet both the IM&E reduction standards, the cost had to be corrected 

using EPA’s cost correction formulas, resulting in an annualized cost of $130,007. While 

this cost is less than half the cost for both the fine-mesh Ristroph screens and narrow-slot 

wedge wire screens, EPA has not defined “significantly greater than.” Therefore, it is not 

possible to determine, with any certainty, when the “significantly greater than” threshold 

has been exceeded. 

• Calculation of benefits is beyond the scope of this analysis. In addition, the existing 

entrainment data and most of the existing impingement data was collected in the late 

1970’s and may not meet the standards necessary for inclusion in the IM&E Study. Until 

the completion of the IM&E study, benefits associated with each alternative may not be 

possible to calculate. Therefore, The Alden did not determine if Harbor would qualify 

for a site-specific BTA determination via the Cost-Benefit test. Data from the late-1970s 

indicate that impingement at Harbor was relatively low. The Team believes that if 

current levels of impingement continue to be low, then benefits of IM&E reduction 

technologies may not justify their costs. 
ES-3 

• Compliance Alternative 1 (IM standard) and Compliance Alternative 2 (entrainment) 

appear to be the most likely tracks by which LADWP could achieve compliance at 

Harbor. 

• Monitoring and re-permitting costs for Harbor could be as high as $700,000 depending 

on the compliance alternative selected and the level of testing that is requested by the 

Director. 

As cited in the Rule, LADWP should be prepared to: 

1. Collect Source Water Physical Data– LADWP may need to supplement existing salinity 

and temperature gradients and determine the intake’s area of influence for the CWISs. 

2. Collect Cooling Water Intake Data – Most of the necessary information is available in 

previous 316(b) filings. However, LADWP should confirm the existing configuration 

and operating conditions of Harbor’s CWIS with plant operators. 

3. Develop a Proposal for Information Collection – LADWP would have to submit to EPA 

the combination of intake technologies, operational methods, and/or restoration measures 

being evaluated, the information that is to be collected, and any sampling plans for field 

studies being proposed. 

4. Conduct the Impingement Mortality and Entrainment Characterization Study (IM&E 

Study) – LADWP would need to sample the current rate of entrainment and possibly 

impingement, as well as study the survival of impinged organisms. Sampling over 1-2 

years may be required to adequately characterize the populations of organisms impinged 

and entrained at Harbor’s CWIS. Since Harbor’s CWIS is significantly different than the 

“calculation baseline”, LADWP may want to conduct additional sampling in front of the 

intake, to determine if the existing design of the CWIS provides a reduction in IM&E 

from the “calculation baseline”. LADWP should identify available data from federal and 

state resource agencies, colleges and universities, or other facilities in the vicinity of 

Harbor which may be used in addition to or in lieu of any waterbody sampling. EPA 

estimated the cost for such studies could as high as $963,501. Site-specific factors may 

increase or decrease these costs depending upon the intensity and duration of monitoring 

approved by California Environmental Protection Agency (CalEPA). 

Depending on the compliance alternative chosen, LADWP may have to collect some or all of the 

information required in the Comprehensive Demonstration Study (CDS). As part of these 

efforts, LADWP may have to: 

a) Design and Construction Technology Plan (D&C Technology Plan) – This study will be 

used to determine the applicability and costs of different technological, operational, and 

restoration measures at Harbor. This study can be used in examining the potential for 

applying for a site-specific BTA determination. 

b) Supply EPA with the Information to Support a Site-Specific Determination of BTA: 
ES-4 

i) Compare the cost EPA used for your facility to the site-specific costs for meeting the 

performance standards. 

ii) Calculate the benefits of each potential alternative (this involves calculating annual 

equivalent adult and production foregone losses relative to impingement and 

entrainment). 

iii) Perform detailed BTA analysis for options to reduce both IM&E per performance 

standard requirement. LADWP should estimate costs of technologies and monetize 

the benefits of impingement mortality and entrainment reductions. Cost-Cost and 

Cost-Benefit tests should be applied and the results assessed. If the requirements of 

either the Cost-Cost or Cost-Benefit tests are satisfied, LADWP should negotiate with 

CalEPA for a site-specific BTA determination. If the cost of retrofitting the CWIS 

technologies is not “significantly greater than” either EPA’s cost estimate or the 

monetized benefits that will be attained, the following additional actions will be 

required: 

(1) Compare technology options (efficacy and costs) with restoration options and 

decide which combination of options is most appropriate at Harbor. 

(2) If restoration is determined to be a viable option, initiate consultation with 

CalEPA and others. Costs range from as low as $1 million (the cost for initial 

construction and development of Mirant’s Chalk Point hatchery) to $14-20 

million, the current estimate for wetland restoration by Duke Energy North 

America for fish losses at their Morro Bay, California plant. 

(3) Initiate actions to reduce entrainment and potentially impingement at Harbor, 

directly via technology/operational alternatives or indirectly via restoration 

measures. 

(4) Monitor for a minimum of two years following the implementation of the chosen 

alternative(s) to verify full-scale performance of technologies, operational 

measures, and/or restoration measures implemented at Harbor. The cost to 

adequately verify performance may be in the $200,000 to $600,000 range. 
i 

Table of Contents 

EXECUTIVE SUMMARY .......................................................................................................ES-1 

Section 1 INTRODUCTION ...........................................................................................................1 

Section 2 DESCRIPTION OF HARBOR GENERATING STATION...........................................6 

2.1 Plant Features.................................................................................................................. 6 

2.2 Intake Structures ............................................................................................................. 6 

2.3 Existing Hydraulic Conditions........................................................................................ 7 

2.4 Biological Considerations............................................................................................... 7 

2.4.1 Characterization of Impingement and Entrainment at Harbor.................................... 7 

2.4.2 Threatened, Endangered, or Other Protected Species................................................. 8 

2.5 Evaluation of Existing Information ................................................................................ 9 

2.5.1 Applicability of the Rule at Harbor ............................................................................ 9 

2.5.2 Baseline Characterization ........................................................................................... 9 

Section 3 ASSESSMENT OF FISH PROTECTION TECHNOLOGIES.....................................23 

3.1 Evaluation Criteria........................................................................................................ 23 

3.2 Identification of Intake Alternatives with Potential for Application ............................ 24 

3.3 Reduced Flow Alternatives Selected ............................................................................ 28 

Section 4 DETAILED EVALUATION OF ALTERNATIVES....................................................32 

4.1 Assessment of Alternatives with Potential for Application.......................................... 32 

4.2 Add Fine Mesh Ristroph Screens to the Existing Screenhouse.................................... 32 

4.3 Retrofit Intake with 0.5 mm Wedge Wire Screens....................................................... 34 

4.4 Existing Operations....................................................................................................... 35 

4.5 Retrofit Plant with Closed-Cycle Cooling System ....................................................... 36 

Section 5 RESTORATION AS A 316(B) COMPLIANCE OPTION AT LADWP’S HARBOR 

GENERATING STATIONS .............................................................................................42 

5.1 What Are the Implications of the Recent Court Ruling Regarding the Use of 

Restoration in the EPA Phase I Rule to Their Use in Phase II? ............................................... 42 

5.2 Why Should LADWP Consider Restoration?............................................................... 43 

5.3 Types of Restoration Applicable to §316(b)................................................................. 44 

5.4 Role of Restoration in the EPA Phase II Rule .............................................................. 45 

5.5 Potential Restoration Measures for LADWP’s Haynes, Harbor, and Scattergood 

Generating Stations................................................................................................................... 47 

5.6 Implementing a Restoration Program for LADWP’s Haynes, Harbor, and Scattergood 

Generating Stations................................................................................................................... 54 

5.7 Information That LADWP Must Submit ...................................................................... 59 

5.8 Summary....................................................................................................................... 59 

Section 6 ESTIMATED COSTS ...................................................................................................64 

6.1 EPA Costs ..................................................................................................................... 64 

6.2 Estimated Costs for Technology Intake Alternatives ................................................... 66 

6.3 Permitting and Monitoring Costs.................................................................................. 67 
ii 

6.4 Cost-Cost Test............................................................................................................... 68 

6.5 Cost-Benefit Test .......................................................................................................... 69 

Section 7 CONCLUSIONS............................................................................................................74 

7.1 Phase II Facility Determination .................................................................................... 74 

7.2 Applicability of Compliance Alternatives .................................................................... 74 

7.3 Compliance Methods .................................................................................................... 75 

7.3.1 Technologies and Operational Measures.................................................................. 75 

7.3.2 Restoration ................................................................................................................ 76 

7.4 Site-Specific Compliance Deadline .............................................................................. 77 

7.5 Overview of Compliance Options ................................................................................ 77 

Section 8 REFERENCES ..............................................................................................................79 

Appendix A OVERVIEW OF THE RULE.............................................................A-1 

Appendix B OVERVIEW OF INTAKE TECHNOLOGIES AVAILABLE FOR FISH 

PROTECTION......................................................................................B-1 

Appendix C OVERVIEW OF REDUCED FLOW OPTIONS FOR FISH PROTECTION......C-1
iii 

List of Tables 

Table 1-1 Applicable National Performance Standards Based On Waterbody Type, Capacity 

Utilization Rate, and Design Intake Flow (EPA 2004a)......................................................... 4 

Table 1-2 Alternative Methods for Complying with the Rule....................................................... 5 

Table 2-1 Pertinent Project Data – Harbor Generating Station ................................................... 10 

Table 2-2 Family, Scientific Name and Common Name of Species Collected at Harbor 

Generating Station ................................................................................................................ 13 

Table 2-3 Diel Larvae Size Entrained at Harbor Generating Station from October 1978 through 

November 1979..................................................................................................................... 13 

Table 2-4 Abundant Species Collected in Impingement Samples from October 1978 through 

November 1979 at Harbor Generating Station ..................................................................... 14 

Table 2-5 California Department of Fish and Game Listed Endangered and Threatened Species 

(http://www.dfg.ca.gov/whdab/pdfs/TEAnimals.pdf))......................................................... 15 

Table 2-6 EPA Definition of “Phase II Existing Facility”........................................................... 16 

Table 2-7 Criteria for Eliminating the Entrainment Reduction Standard at Harbor Generating 

Station ................................................................................................................................... 16 

Table 2-8 Criteria for “Calculation Baseline” ............................................................................. 17 

Table 3-1 Initial Screening of Fish Protection Alternatives at Harbor ........................................ 30 

Table 5-1 EPA Requirements for the Content of Restoration Plans............................................. 61 

Table 6-1 EPA Cost Modules ....................................................................................................... 70 

Table 6-2 Cost EPA Estimated for Harbor Generating Station .................................................... 71 

Table 6-3 Alden’s Appraisal Level Costs of Evaluated Alternatives........................................... 72 

Table 6-4 Comparison of Alden and EPA Permitting and Monitoring Costs .............................. 73 
iv 

List of Figures 

Figure 2-1 Vicinity Map of the Harbor Generating Station......................................................... 18 

Figure 2-2 Aerial Photo of Harbor Generating Station................................................................ 19 

Figure 2-3 Harbor Generating Station Intake Structure — Plan.................................................. 20 

Figure 2-4 Harbor Generating Station Screenhouse — Section .................................................. 21 

Figure 2-5 Harbor Generating Station Screenhouse — Plan....................................................... 22 

Figure 4-1 Typical Ristroph Screen – Section............................................................................. 39 

Figure 4-2 0.5 mm Wedge Wire — Plan ..................................................................................... 40 

Figure 4-3 0.5 mm Wedge Wire — Section ................................................................................ 41 
1 

Section 1 

INTRODUCTION 

Section 316(b) of the Clean Water Act (CWA) requires that the location, design, construction, 

and capacity of a cooling water intake structure (CWIS) reflect the “best technology available” 

(BTA) for minimizing adverse environmental impact (AEI). AEI from CWISs occurs1 as the 

result of entrainment of small aquatic organisms through the CWIS and into the cooling water 

system and the impingement of larger organisms on traveling water screens. On July 9, 2004, 

EPA published the final rule for implementing §316(b) of the CWA for Phase II Existing 

Facilities (the Rule). The Rule dictates the use of technological, operational, or restoration 

measures to achieve an 80–95% reduction in impingement mortality at all Phase II facilities and 

a 60–90% reduction in entrainment from a “calculation baseline” at some Phase II Facilities. A 

summary of the Rule is provided in Appendix A. 

As defined in the Rule, a Phase II Existing Facility is any point source facility that commenced 

construction before January 17, 2002; has a design flow of greater than 50 million gallons per 

day (MGD), at least 25% of which is used for cooling purposes; and generates electric power 

primarily for transmission or sale. The “calculation baseline” is an estimate of impingement and 

entrainment that a facility could expect if it had a shoreline intake, a capacity commensurate with 

a once-through cooling system, and no impingement or entrainment reducing technologies. 

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

Laboratory, Inc., (Alden) collectively referred to as “the Team,” have conducted a strategic 

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

Station (Harbor). This assessment evaluates the impact of the Rule on Harbor, including 

potential cost-effective compliance alternatives, additional information collection needs, and 

relative budget impacts as a result of studies and compliance alternatives. LADWP could use 

some of the information contained in this report in the Comprehensive Demonstration Study 

(CDS) the Rule requires for submittal. 

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

technologies (EPA’s “Design and Construction Technologies”) to meet the applicable 

performance standards for Harbor and our discussion of approximate costs for the feasible 

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

meeting the applicable performance standards. This alternatives analysis is the first step in 

developing a compliance strategy and provides a basis for preparing the Proposal for Information 

Collection (PIC). In addition, the adequacy of existing biological information is evaluated for its 

ability to support technology selection and meet the requirements of the CDS. 

This report addresses technologies, operational changes, and restoration measures that LADWP 

can implement to meet the Rule. EPA’s currently favored approach is to reduce total fish losses, 

which does not address AEI at the population and ecosystem levels. Therefore, the Team does 

not address traditional measures of population and ecosystem health, such as species diversity 

 

1

 EPA has not defined AEI but has implicitly defined it as impingement mortality and entrainment 
2 

and richness, in this report. Further, EPA does not consider factors that influence populations 

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

factors are not considered here. However, if LADWP determines that restoration is more 

feasible, cost-effective, or environmentally sound then any other alternative at Harbor, then 

ecosystem health, as well as the status of fish community and populations in the source 

waterbody would be considered. 

EPA’s preferred alternative involves the use of national performance standards, i.e., a reduction 

in impingement mortality (IM) of all life stages of fish and shellfish of 80–95% from the 

“calculation baseline,” and at some facilities, a reduction in entrainment (E) of all life stages of 

fish and shellfish by 60–90% from the “calculation baseline” (EPA 2004a § 125.94[b]). 

Facilities that EPA requires to meet the entrainment reduction standard are those facilities that 

have a capacity utilization rate2

 of 15% or greater and withdraw water from a tidal river, estuary, 

ocean, or Great Lake. IM&E standards also apply to facilities that are located on a freshwater 

river and have a design intake flow greater than 5% of the mean annual river flow. Table 1-1 

shows a summary of which performance standards apply to each waterbody. Conditions 

applicable to Harbor are identified in bold. 

The “calculation baseline” is an estimate of impingement mortality and entrainment that would 

occur at a facility designed and operated in the following ways: 

• The cooling water system has been designed as a once-through system; 

• The opening of the cooling water intake structure is located at the shoreline and the face 

of the standard 3/8-inch mesh traveling screen is oriented parallel to the shoreline near 

the surface of the source waterbody; 

• The baseline practices, procedures, and structural configuration are those that a facility 

would maintain in the absence of any structural or operational controls that would reduce 

IM&E, including flow or velocity reductions, implemented in whole or in part for the 

purposes of reducing impingement mortality and/or entrainment. 

EPA has allowed for some flexibility in the “calculation baseline” at the facility level. EPA 

permits a facility to use the current level of IM&E as the “calculation baseline.” This could 

potentially streamline the permit application since the facility could determine the baseline using 

 

2

 The capacity utilization rate is the ratio between the average annual net generation of power by the facility (in 

MWh) and the total net capability of the facility to generate power (in MW) multiplied by the number of hours 

during a year. In cases where a facility has more than one intake structure, and each intake structure provides 

cooling water exclusively to one or more generating units, a facility can calculate the capacity utilization rate 

separately for each intake structure based on the capacity utilization of the units it services. EPA would then 

determine applicable requirements under this subpart separately for each intake structure. The facility should 

measure the average annual net generation over a 5-year period (if data are available) of representative operating 

conditions, unless it makes a binding commitment to maintain capacity utilization below 15% for the life of the 

permit, in which case it may base the rate on this commitment. For purposes of this regulation, the capacity 

utilization rate applies to only that portion of the facility that generates electricity for transmission or sale using a 

thermal cycle employing the steam water system as the thermodynamic medium (EPA 2004a §125.93). 
3 

data collected during the IM&E Study (a requirement of the CDS, described below). A facility 

may also request that EPA use an alternative intake location (e.g., at a depth other than at or near 

the surface or at a location other than the shoreline) if the utility can demonstrate to the Director 

that the alternate location would correspond to a higher baseline level of IM and/or entrainment. 

A facility may estimate the calculation baseline using: 1) historical IM&E data from a facility; 2) 

IM&E data from another facility with comparable design, operational, and environmental 

conditions; 3) current biological data collected in the waterbody near the CWIS; 4) or current 

IM&E data collected at a facility. 

There are five compliance alternatives that EPA indicates a facility may use to comply with 

§316(b) of the Clean Water Act. All five compliance options, as EPA states, will achieve a 

reduction in impingement mortality by 80–95% and in entrainment (where applicable) by 60–

90% (or equivalent environmental benefit) for all Phase II Existing Facilities. The five 

Compliance Alternatives are outlined in Table 1-2. A full discussion of each of the Alternatives 

along with their required studies is provided in Appendix A. 

This report is structured in the following way: 

• Section 2 – provides a summary of existing engineering and biological information for 

Harbor and assesses the potential for the existing design and operation of the CWIS to 

meet EPA’s impingement mortality (IM)reduction standard 

• Section 3 – defines criteria for selecting alternative fish protection technologies and 

selects technologies that hold the greatest potential to meet EPA’s IM reduction standard 

for further evaluation 

• Section 4 – provides preliminary engineering information for selected alternatives 

• Section 5 – discusses restoration as an option for complying with the Rule 

• Section 6 – estimates potential compliance costs, including permitting, technology, and 

EPA costs 

• Section 7 – summarizes the key findings of the Team’s analysis. 

• Appendix A – presents an overview of the Rule 

• Appendix B – summarizes alternative fish protection technologies 

• Appendix C – discusses reduced flow options 
4 

Table 1-1 Applicable National Performance Standards Based On Waterbody Type, 

Capacity Utilization Rate, and Design Intake Flow (EPA 2004a) 

Waterbody Type

Capacity Utilization 

Rate Design Intake Flow 

Type of Performance 

Standard

Less than 15% N/A Impingement 

mortality only 

5% or less of mean 

annual flow 

Impingement 

mortality only 

Freshwater river or 

stream 

Equal to or greater 

than 15% 

Greater than 5% of 

mean annual flow 

Impingement 

mortality and 

entrainment 

Less than 15% N/A Impingement 

mortality only 

Tidal river, estuary, 

or ocean 

Equal to or greater 

than 15% 

N/A Impingement 

mortality and 

entrainment 

Less than 15% N/A Impingement 

mortality only 

Great Lakes 

Equal to or greater 

than 15% 

N/A Impingement 

mortality and 

entrainment 

Lakes or reservoirs N/A Increase in design 

intake flow must not 

disrupt thermal 

stratification except 

where it does not 

adversely affect the 

management of 

fisheries. 

Impingement 

mortality only 
5 

Table 1-2 Alternative Methods for Complying with the Rule 

Alternative Description 

Alternative 1 Flow commensurate with closed cycle cooling (meets both IM&E standards) or the 

design through-screen velocity is less than 0.5 ft/s (meets only the IM standard) 

Alternative 2 Existing CWIS uses BTA to meet the performance standards 

Alternative 3 Proposed technologies, operational changes, and/or restoration will meet the 

performance standards 

Alternative 4 Install, operate, and properly maintain an EPA approved technology 

Alternative 5 Apply a site-specific BTA determination by satisfying the requirements of the CostCost or Cost-Benefit tests 

6 

Section 2 

DESCRIPTION OF HARBOR GENERATING STATION 

2.1 Plant Features 

Harbor Generating Station (Harbor) is located in the Inner Los Angeles Harbor Complex 

(ILAHC), in Wilmington, CA near Long Beach, as shown on Figure 2-1. Harbor has eight 

natural gas fired units, seven of which do not require circulating water; only Unit 5 requires 

using circulating water from the harbor. Units 1 & 2 are combined cycle combustion turbines 

with heat recovery steam generators. Unit 5 is a steam turbine with two circulating water pumps 

that provide 83.5 cfs (75,000 gpm) of circulating water at full load. Units 10 - 14 are gas 

turbines equipped with cooling towers. 

The total plant output is 470 MW with Units 1 & 2 rated at 80 MW each, Unit 5 rated at 75 MW, 

and Units 10 - 14 each rated at 47 MW. Unit 5 has a capacity factor of 23% based upon an 

average of years 2002 - 2003. Table 2-1 presents a summary of pertinent plant data. 

Cooling water for Unit 5 is withdrawn from the ILAHC through an intake structure along the 

shore of Slip 5, as shown in Figure 2-2. The mean water depth in front of the intakes is 21 ft. 

Trash racks are installed across the CWIS to prevent large debris from entering the intake bays. 

To further screen the intake water, vertical traveling screens are located in a separate 

screenhouse structure located inland of Slip 5. Water is transported from the intake structure to 

the screenhouse via a 1,095 ft long, 8 ft diameter pipe. Two circulating water pumps are located 

downstream of the traveling water screens to convey screened flow to the condensers. The 

remainder of the facility’s water needs is provided by municipal raw water. Cooling water is 

transported through a 1,393 ft long pipe to the discharge structure in L.A. Harbor’s West Basin 

(Figure 2-2). The location and setup of the discharge canal prevents discharged water from recirculating into the intake. 

2.2 Intake Structures 

Harbor is located about 23 miles south of downtown Los Angeles. The CWIS is located in the 

northwest corner of the Slip 5, and is surrounded by rip rap 25 feet below the water surface at the 

face of the intake. A plan showing the intake structures at Harbor is provided on Figure 2-3. 

The Unit 5 CWIS is equipped with six vertical bar racks to deflect large debris. The bar racks 

are made out of 3/8 in. by 3 in. bars spaced 4.5 in. on center. Cleaning of the bar racks is done 

on a weekly basis or as needed. The screenhouse is located onshore, and connected to the intake 

structure by two, 8 ft diameter pipes, each 1,095 ft long. Two vertical cooling water pumps and 

six screenbays with traveling water screens are located within the screenhouse. Two of the 

screens are in continual use, two are permanently blocked with stop logs, and the remaining two 

are used during high flow conditions (both pumps in operation). The water is then discharged 

into the West Basin of L.A. Harbor. 

The screen bays are about 8.0 ft wide, with the invert at El. -16.0 ft. All elevations in this report 

correspond to Mean Sea Level (MSL). The top of the intake pipes are at El. -8.0 ft when they 
7 

enter the screenhouse. The traveling water screen is located about 33.5 ft downstream where the 

intake pipes enter the screenhouse. A section and plan of the screenhouse are shown on 

Figure 2-4 and Figure 2-5, respectively. The screens are 6 ft wide and extend from the invert of 

the screenhouse to the top deck. The screen baskets have a 3/8 in.square bronze wire mesh. The 

screens they are rotated once every 8 hour shift for thirty minutes. A back wash system 

providing up to 800 gpm of cleaning water at 70 psig is used to remove debris from the screens. 

Screenwash water and debris are collected in a rectangular trough that flows into the ILAHC 

near the face of the intake. 

Circulating water to Unit 5 is provided by two single stage vertical mixed flow pumps. The inlet 

of these pumps is at El. -14.5 ft. Each of the pumps is rated at 305 hp at 514 rpm and provides a 

flow of 83.5 cfs (37,500 gpm) each. 

2.3 Existing Hydraulic Conditions 

The ILAHC is a heavily industrialized area, with the intake and discharge sites entirely 

surrounded by dockage, wharves and container terminals. The bottom of the ILAHC is mainly 

covered in about 3 ft of silt. Within the ship channels the bottom had been dredged to a depth of 

about 60 ft. 

Velocities inside the circulating water system were calculated using the facility design flow of 

83.5 cfs, flow through all four screen bays, and the mean lower low water level (El. 0.0 ft). 

Under these conditions, the water velocity at the face of the CWIS was calculated to be 0.2 

ft/sec. With both circulating water pumps are operating, this approach velocity corresponds to a 

through-screen velocity of about 0.4 ft/sec, assuming a 50% net flow area that is typical for 

traveling water screens. 

2.4 Biological Considerations 

The selection of technologies for the protection of aquatic organisms at Harbor to meet the 

performance standard is based, in part, upon the species and life stages of fish in the vicinity of 

the intake, their temporal and spatial abundance, and their relative hardiness. Since the 

performance standards are based upon a reduction over an existing baseline, some understanding 

of current fish and shellfish populations is required to make predictions about the efficacy of 

potential technological options. Based on available information, the species and life stages 

considered in this evaluation of alternatives are presented in Table 2-2. 

2.4.1 Characterization of Impingement and Entrainment at Harbor 

A complete year-long impingement and entrainment survey was conducted at Harbor by Intersea 

Research Corporation (Intersea) from October 1978 through November 1979. A summary of 

fish species collected is presented in Table 2-2. During the study, entrainment samples were 

collected biweekly. Samples were collected with a 202 micron mesh plankton net at the intake 

conduit structure located within slip number five along the East Basin Channel. Larvae and eggs 

washed from the nets were counted, preserved, and identified to the lowest possible taxonomic 
8 

level. Larvae were measured to the nearest millimeter. Densities were measured in number of 

individuals per unit of volume of water sampled (m3). The total annual entrainment of 

ichthyoplankton was calculated by multiplying biweekly density estimates and the biweekly flow 

volumes then summing the results for the entire year. The most abundant eggs sampled were of 

the family Sciaenidae, with maximum density occurring from January to April. An estimated 

annual entrainment of 3.9 x 108

 Sciaenidae eggs was determined. The most frequently entrained 

larvae were: anchovies (Engraulidae) — 1.0 x 108

, gobies (Gobiidae) — 5.2 x 108, blenny 

(Hypsoblennius spp.) — 1.9 x 107, and white croaker (Genyonemus lineatus) — 5.2 x 107. The 

larvae entrained during the sample period were measured and placed into one of 4 size intervals 

with a percent composition being calculated for each interval and species, these data are 

presented in Table 2-3. The extent of the QA/QC that was applied to the entrainment data is not 

clear. 

Impingement samples were collected over a total of 34, 24-hour samples collected weekly. 

Individuals were collected within debris baskets. Individuals collected were weighted, measured 

to the nearest millimeter, and identified to the lowest possible taxonomic level. A total of 17,632 

fish representing nine species were impinged during the study (Table 2-4). Four species 

comprise 86.7 % of the total impingement; Pacific pompano (Peprilus simillimus) 30.6 %, white 

croaker 28.9 %, queenfish 16.6 %, and shiner surfperch (Cymatogaster aggregata) 10.6 %. An 

estimated annual impingement of 164,225 was calculated for the 1978-79 study period. 

Impingement samples were not collected in April or May of 1979. The reasoning for the 

absence of April and May impingement sample data is unknown. This missing data makes it 

difficult to demonstrate seasonal variability in impingement. It is unclear as to what extent 

QA/QC was applied to the impingement data. 

More recent biological information was gathered at Harbor from September 2003 to January 

2004. This four month study consisted of only three sample dates during which 52 fish were 

impinged. 90% of those impinged during the 2003-04 study consisted of; Haller’s round ray 

(Urolophus halleri), giant kelpfish (Heterostichus rostratus), and black surfperch (Embiotoca 

jacksoni). These three species were not present among the most abundantly impinged species of 

the 1978-79 study. The limited sampling in 2003–2004 is insufficient to draw conclusions about 

the current species composition or abundance near Harbor. Harbor may need to monitor current 

levels of IM&E for a minimum of one year to determine if species composition and abundance 

has changed since the previous data were gathered. If I&E has changed substantially, a second 

year of sampling may be necessary to fulfill the requirement of the IM&E Study. 

2.4.2 Threatened, Endangered, or Other Protected Species 

As part of the IM&E study, the Rule would require: 

“Taxonomic identifications of all life stages of fish, shellfish, and any species protected 

under federal, state, or tribal law (including threatened or endangered species) that are 

in the vicinity of the cooling water intake structure(s) and are susceptible to impingement 

and entrainment...” (§ 125.95 (b) (3) (1) EPA 2004a) 
9 

Additionally, more stringent requirements may be applied to a facility if any of these specified 

circumstances (e.g., located where additional protection is needed due to concerns regarding 

threatened, endangered, or protected species or habitat, or regarding migratory, sport, or 

commercial species) occur. The California Department of Fish and Game maintains a list of the 

state’s threatened, endangered, and protected species (Table 2-5). None of the species listed 

have appeared in entrainment or impingement samples collected at Harbor. 

2.5 Evaluation of Existing Information 

The current plant configuration plays an important role in determining what performance 

standard will apply to Harbor. If this configuration is not consistent with the “calculation 

baseline” then there may be potential to receive credit towards these standards. 

2.5.1 Applicability of the Rule at Harbor 

The Rule requires all Phase II Existing Facilities to meet specific national performance 

standards, achieve an environmental benefit that is substantially similar to what would be 

achieved if a facility were to comply with the national performance standards, or, under certain 

circumstances, meet alternative, less restrictive, performance standards. The requirements for a 

Phase II Existing Facility are listed in Table 2-6. Since Harbor meets all the criteria for a Phase 

II facility, it will be required to meet the applicable performance standards based on waterbody 

type and plant flow. The criteria used to determine which performance standards are required for 

the CWIS are shown on Table 2-7. As Unit 5 withdraws water from the ILAHC, and has a 

capacity factor of greater than 15%, the current capacity factor is about 23% (Jan 2002 – Dec 

2003), it would be required to meet both IM&E reduction standards. 

2.5.2 Baseline Characterization 

Harbor’s CWIS is not configured and/or operated in a manner consistent with EPA’s 

“calculation baseline” (Table 2-8). The top of the intake is located at El. -11.0 ft, which is 11 ft 

below the mean lower low water level, which causes water to be withdrawn from below the 

surface. The traveling screens also have a fish return which may offer some reduction in 

impingement mortality over what would be expected if Harbor were configured and operated in 

the “baseline” condition. The CWIS was designed to handle the flow for five units, as it is now 

only used buy one unit (Unit 5), which results in significantly less flow entering the CWIS. This 

reduced flow result in the velocities within the CWIS and screenhouse being very low and may 

meet the IM reduction standard via Compliance Alternative 1. Any decrease in IM&E that can 

be attributed to these deviations from “calculation baseline” can be credited toward meeting the 

national performance standard. 

Additional credit toward meeting the standard can occur if a facility re-circulates a portion of its 

flow or has incorporated technologies, operational, or restoration measures specifically to reduce 

IM&E. From the information provided, the Harbor facility does not re-circulate any of the 

cooling water flow, does not have any other operational practices in place that may protect 

organisms susceptible to IM&E and has not engaged in any restoration. Therefore, LADWP will 

be unable to take additional credit from these practices toward meeting the IM&E standards. 
10 

Table 2-1 Pertinent Project Data – Harbor Generating Station 

Location 

161 Island Ave, Wilmington CA, 90774 

Latitude: 33.7672° N 

Longitude: 118.2661° W 

Waterbody: L.A. Harbor

Waterbody type: Tidal River

EPA ID #: DUT1138 

NPDES ID #: CA0000361 

Permit Expiration Date: June 10, 2008 

Estimated project intake flow 

Maximum: 167 cfs (75,000 gpm) 

Minimum: 83.5 cfs (37,500 gpm) 

Plant Design: 167 cfs (75,000 gpm)

Intake velocities: (approach) 

One Pump 

Trash racks: 0.2 ft/sec 

Screenbays: 0.4 ft/sec (2 screens in operation) 

Screenbays: 0.2 ft/sec (4 screens in operation) 

Two Pumps 

Trash racks: 0.3 ft/sec 

Screenbays: 0.4 ft/sec (4 screens in operation) 

Water Level 

Elevations 

HWL: El. 7.5 ft 

MLLW: El. 0.0 ft 

LWL: El. -1.7 ft 

MSL: El. 2.9 ft 

Water Depths 

In front of CWIS 

Maximum: 42.5ft 

Minimum: 33.3ft 

MMLW: 35 ft 

MLS: 37.9 ft 

Project Structures 

CWIS 

Location: Slip 5 L.A. Harbor 

Configuration: along shoreline 

Length: 56 ft 

Invert at face: El. -21.0 ft. 

Top: El: -11.0 ft 

Trash rack location: face of intake 

Trash rack material: 3/8 in. x 3 in. bars 

Trash rack spacing: 4.5 in. on-center 

Trash rack cleaning: weekly or when needed 
11 

Table 2-1 Continued

Intake Pipes 

Number: 2 

Length: 1,095 ft 

Inner diameter: 8 ft 

Invert: El. -20.0 ft (CWIS) 

Invert: El. -16.0 ft ( screenhouse) 

Screenhouse 

Location: end of intake pipes 

Number of bays: 6 

Bay width: 7 ft 11.5 in. 

Invert: El. -16.0 ft 

Top of structure: El. 12.0 ft 

Other info: 2 bays permanently blocked, 2 bays in use when one Circulating water Pump in 

use, 4 bays used when both pumps operating 

Traveling water screens 

Location: screenhouse 

Number: 6 

Width: 6 ft 

Mesh material: bronze 

Mesh size and geometry: 3/8 in. sq. mesh 

Spray nozzle configuration: back wash 

Spray pressure: 70 psig 

Spray volume: 800 gpm (2pumps at 400gpm) 

Operation: rotated for 30 minutes every 8 hour shift 

Debris/fish return: rectangular trough 

Trough discharge: back into the ILAHC 

Circulating water pumps 

Number of pumps: 2 

Types of pumps: vertical, single speed, mixed flow 

Pump inlet: El. -14.5 ft 

Invert: -19.0 ft 

Rating: 305 hp @ 514 rpm 

Flow per pump: 83.5 cfs (37,500 gpm) 

Flow with both pumps operating: 167 cfs (75,000 gpm) 

Cooling water discharge 

Location of discharge: Cooling water is transported through a 1,393 ft long pipe to the 

discharge structure in L.A. Harbor’s West Basin, preventing recirculation.
12 

Table 2-1 Continued

Power Generation 

Fuel type: gas 

Facility output 

Units 1&2: 80 MW (each) 

Unit 5: 75 MW 

Unit 10-14: 47.5 MW (each) 

Facility total: 473 MW 

Operating mode: peaking 

Plant capacity factor: 32% (1999-2003 Units 1,2&5) 

Unit 1: 27% (Jan 02 – Dec 03) 

Unit 2: 28% (Jan 02 – Dec 03) 

Unit 5: 23% (Jan 02 – Dec 03) 

Estimated remaining plant life: 15 yrs 

Average annual energy: 658,458 MWh (gross) (1999-2003) 

 1,065945 MWh (net) (Jan 02 – Dec 03) 
13 

Table 2-2 Family, Scientific Name and Common Name of Species Collected at Harbor 

Generating Station 

Family Scientific Name Common Name 

Blenniidae Hypsoblennius spp.

Carangidae Trachurus symmetricus Pacific jack mackerel 

Embiotocidae Cymatogaster aggregata shiner surfperch 

Engraulis mordax northern anchovy Engraulidae Anchoa compressa deepbody anchovy 

Gobiidae Acanthogobies flavimanus yellowfin goby 

Genyonemus lineatus white croaker Sciaenidae Seriphus politus queenfish 

Stromateidae Peprilus simillimus Pacific pompano 

Urolophidae Urolophus halleri Haller's round ray 

Table 2-3 Diel Larvae Size Entrained at Harbor Generating Station from October 1978 

through November 1979 

Percent Size Composition 

Species Diel 

Mean 

Size 

(mm) 

Standard 

Deviation 

Total 

(No.Larvae/100 

m3

) <5mm 

5-

10mm 

10-

15mm >15mm 

anchovy Day 15.6 8.2 139 3 25 42 30 

Night 17.6 7.8 1,262 <1 10 52 38 

gobies Day 4.6 1.5 5,294 83 16 1 <1 

Night 4.4 1.4 18,159 92 7 2 <1 

blenny Day 4.3 1.0 136 90 10 0 0 

Night 4.3 1.0 118 91 9 0 0 

white Day 3.4 0.8 296 96 4 0 0 

croaker Night 4.2 2.2 369 81 15 4 0 
14 

Table 2-4 Abundant Species Collected in Impingement Samples from October 1978 through November 1979 at Harbor 

Generating Station 

Species Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov

Total 

Collected

Percent 

Composition

Pacific pompano 

274 689 1,902 2,104 94 - - 67 87 150 20 9 0 5,396 30.6

white croaker 

177 140 100 2,223 498 - - 1,043 306 372 149 90 4 5,102 28.9

queenfish 14 48 51 1,910 462 - - 248 103 70 17 12 0 2,935 16.6shiner surfperch 

79 138 36 660 183 - - 204 104 206 160 130 3 1,873 10.6

yellowfin goby 

64 266 69 329 160 - - 84 26 46 26 58 2 1,130 6.4

Pacific jack mackerel 

17 34 40 103 14 - - 5 5 4 11 4 0 237 1.3

Haller’s round ray 

7 0 0 0 0 - - 3 41 48 42 22 0 163 0.9

deepbody anchovy 

4 8 0 57 33 - - 3 2 5 1 0 0 113 0.6

northern anchovy 

1 2 8 0 0 - - 19 2 9 7 0 0 48 0.2

Incidental catch 

31 92 16 273 67 - - 30 20 52 34 20 0 635 3.9

Total Number Individuals 

668 1,417 2,222 7,659 1,511 - - 1,706 696 962 437 345 9 17,632 100

Percent Total Catch 4% 8% 13% 43% 9% - - 10% 4% 5% 2% 2% 0%

- April/ May data absent from survey 
15 

Table 2-5 California Department of Fish and Game Listed Endangered and Threatened 

Species (http://www.dfg.ca.gov/whdab/pdfs/TEAnimals.pdf)) 

Family Scientific name Common name 

Salvelinus confluentus bull trout 

Oncorhynchus clarki henshawi Lahontan cutthroat trout 

Oncorhynchus mykiss whitei Little Kern golden trout 

Oncorhynchus tshawytscha Chinook salmon 

Oncorhynchus mykiss steelhead 

Oncorhynchus kisutch coho salmon 

Salmonidae 

Oncorhynchus clarki seleniris Paiute cutthroat trout 

Deltistes luxatus Lost River sucker 

Catostomus microps Modoc sucker 

Xyrauchen texanus razorback sucker 

Catostomus santaanae Santa Ana sucker 

Catostomidae 

Chasmistes brevirostris shortnose sucker 

Gila bicolor vaccaceps Cowhead Lake tui chub 

Gila bicolor mohavensis Mohave tui chub 

Gila bicolor snyderi Owens tui chub 

Cyrinidae 

Gila elegans bonytail 

Cyprinodon salinus milleri Cottonball Marsh pupfish 

Cyprinodon macularius desert pupfish 

Cyprinodontidae 

Cyprinodon radiosus owens pupfish 

Cyprinidae Pogonichthys macrolepidotus Sacramento splittail 

Ptylocheilus lucius Colorado squawfish 

Gobiidae Eucyclogobius newberryi tidewater goby 

Cottidae Cottus asperrimus rough sculpin 

Osmeridae Hypomesus transpacificus delta smelt 

Gasterosteidae Gasterosteus aculeatus williamsoni unarmored threespine stickleback 
16 

Table 2-6 EPA Definition of “Phase II Existing Facility” 

Rule Criteria 

Applicable to 

Harbor? 

point source that commenced construction before 

January 17, 2002 yes 

generates electric power primarily for transmission or 

sale yes 

designed to withdraw ≥ 50 MGDa of water, at least 

25% of which is used for cooling water yes 

 a MGD = millions of gallons per day 

Table 2-7 Criteria for Eliminating the Entrainment Reduction Standard at Harbor 

Generating Station 

Rule Criteria 

Applicable 

to Harbor? 

facility is on a lake or reservoir (other than the Great 

Lakes) no 

withdraws 5% or less of the mean annual flow of a 

freshwater river or stream1 no 

has a capacity utilization rate less than 15%. no 

1. EPA requires percent of mean annual flow to be calculated on the facility level rather than for each individual 

CWIS 
17 

Table 2-8 Criteria for “Calculation Baseline” 

Rule Criteria 

Applicable to 

Harbor? 

The cooling water system has been designed as a oncethrough system yes 

The face of the CWIS is located the shoreline and 

oriented parallel to the shoreline yes 

The cooling water intake structure has standard 3/8-inch 

mesh yes 

Traveling screen is oriented parallel to the shoreline near 

the surface of the source waterbody no 

The cooling water intake structure does not have any 

modifications that would reduce IM&E (Ristroph 

screens, fish return) 

no 

The facility does not have any operating controls to 

reduce IM&E (seasonal shutdown, flow or velocity 

reduction) 

Unknown 
18 

Figure 2-1 Vicinity Map of the Harbor Generating Station
19 

Figure 2-2 Aerial Photo of Harbor Generating Station 

Intake Structure 

Harbor Generating Station 

Discharge Structure 
20 

Figure 2-3 Harbor Generating Station Intake Structure — Plan
21 

Figure 2-4 Harbor Generating Station Screenhouse — Section 
22 

Figure 2-5 Harbor Generating Station Screenhouse — Plan 

23

Section 3 

ASSESSMENT OF FISH PROTECTION TECHNOLOGIES 

3.1 Evaluation Criteria 

EPA supports the adoption of national performance standards for existing CWISs (80-95% 

reduction in impingement mortality and 60-90% reduction in entrainment). Therefore, the 

primary criterion for evaluating alternative technologies is their ability to meet the performance 

standards. At Harbor, both impingement mortality and entrainment reduction technologies were 

evaluated for the CWIS. 

A summary of fish protection technologies available at water intakes is provided in Appendix B. 

An overview of modified circulating water pump operation options and closed-cycle cooling 

systems is presented in Appendix C. Criteria used to evaluate alternatives that may be 

appropriate for application at Harbor are defined in this section. The screening process used for 

selecting alternatives for preliminary evaluation is presented in Section 3.2 for intake 

technologies and Section 3.3 for reduced flow options. 

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

protection technologies for application at Harbor. The criteria were used to evaluate the relative 

advantages and disadvantages of each fish protection alternative and to select for more detailed 

development those alternatives that have the greatest potential to effectively protect fish. The 

criteria represent key aspects to any ultimately successful protection strategy and are not listed in 

order of priority. 

• Alternatives should be designed to reduce impingement mortality of impingeable3

 fish by 

80-95% from the “calculation baseline.” 

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

baseline”. 

• Alternatives should provide protection for species present in the harbor that are 

potentially susceptible to IM&E. 

• The period of protection is year-round for impingement and 9 months for entrainment. 

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

summarized in Table 2-1. 

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

of intake flows and water depths at the CWIS. 

 

3

 EPA defines an entrainable organism as one that will pass through a 3/8 in. mesh. By contrast, an impingeable 

organism is one that will not pass through a 3/8 in. mesh. 
24

• 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 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. 

3.2 Identification of Intake Alternatives with Potential for Application 

The available fish protection technologies were subjected to a screening process to determine 

which technologies offered the greatest potential for practical application at Harbor. The 

screening identified those technologies that have potential for application, as presented below. 

Section 4 presents the development of the selected alternatives for proper installation at Harbor. 

The criteria used to screen the technologies are discussed above in Section 3.1. 

Table 3-1 summarizes results of the preliminary screening of the fish protection technologies. A 

technology was considered to have potential for application at Harbor if: 

1. the technology has proven biological effectiveness, 

2. the technology is available and does not require further engineering development, and 

3. the technology has engineering and/or biological advantages over the other technologies 

evaluated. 

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

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

in which they may never before have been applied, The Team had to use best professional 

judgment based on experience. 

A technology was deemed to have proven biological effectiveness if test data (preferably from 

full-scale application) were available that documented a technology’s effectiveness with one or 

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

conceptual design and/or if the technology has been constructed at another site, it was judged 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 
25

technology may hold an advantage over another if the civil/structural requirements for its 

installation are substantially less. 

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

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

technologies include Beaudrey’s Fish Protection Solution (FPSTM), Filtrex filter system, finemesh flat-panel screens with debris and organism collection (DOC) system, and Geiger’s Multi 

DiscTM Screening System. 

• Beaudrey’s FPSTM system consists of a fine-mesh fixed screen with a fish collection 

scope positioned below the water’s surface. The collection scope travels along the screen 

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

• Filtrex filter system consists of filter “candles” approximately 5 inches long made of 

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

stacked wafers provide filtration from 5 to 40 microns, and the flow capacity of each 

candle is approximately 10 gpm at a headloss of 4 feet. Filter candles are assembled 

together on 3 ft by 3 ft modules with filter arrays on three sides and cleaned using a 

backwash system. During backwashing, the stacked wafers are allowed to separate by 

compression of the central spring, and the backwash flow removes debris. Debris and 

fish then float downstream of the filter modules to a bypass pump and return system. 

• Debris Organism Collection (DOC) System consists of flat panel 0.5 mm screens, a 

debris and organism collection nozzle, a fish pump, and fish return troughs and piping. 

The collection nozzle would be located close to the flat panel screen face just below the 

water’s surface and would remove debris and impinged fish from the screens. 

Submerged fish pumps would create suction for each nozzle. The fish pumps would 

discharge fish and debris through piping and/or troughs back to the source waterbody. 

High-pressure spray wash headers and debris troughs would be located at deck level for 

additional debris removal for each screen. 

• The Geiger Multi DiscTM Screening System consists of a single-pass, front-wash, vertical 

screen with fish handling capabilities. This design results in a “zero carryover” 

fish/debris condition. Mesh size and material (e.g. woven mesh or perforated plate) and 

screen rotation speed can be designed for site-specific needs. 

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

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

fully developed or have not been biologically proven. 

Based on the literature summarized in Appendix B, the following concepts are considered to 

have limited or no proven biological effectiveness (i.e., they have not substantially reduced 

entrainment or impingement in past applications as indicated in Table 3-1): 

• Infrasound 

• Mercury lights 
26

• Chemicals 

• Electric screens 

• Water jet curtains 

• Hanging chains 

• Visual keys 

• Inclined plane screens 

• Submerged traveling water screens 

As discussed in Appendix B, other behavioral barriers have been shown to repel or attract fish by 

eliciting a response to a particular stimulus. In particular, sound, strobe lights, and air bubble 

curtains have been shown to effectively repel several species of fish. However, these 

technologies are only effective with fish in later life stages, since larval fish do not have 

sufficient motility to overcome the flow. Therefore, behavioral barriers cannot be considered as 

alternatives to address entrainment at Harbor. 

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

The use of strobe light 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 

light. Strobe lights have been evaluated for repelling or guiding juvenile and adult fish away 

from water intakes (EPRI 1994, 1999) and, in many cases, towards 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 sitespecific. 

The focus of recent studies involving underwater sound technologies has been on the use of lowand high-frequency acoustic systems that were not available for commercial use until the 1990s. 

High-frequency (120 kHz) sound has been shown to effectively and repeatedly repel members of 

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

(Ploskey et al. 1995; Dunning 1995; Consolidated Edison 1994). Other studies have not shown 

sound to be consistently effective in repelling species such as largemouth bass, smallmouth bass, 

yellow perch, walleye, rainbow trout (EPRI 1998), gizzard shad, Atlantic herring, and bay 

anchovy (Consolidated Edison 1994). 

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

barrier consisting of light, sound, and air bubbles would be most effective on Alosids. Little or 

no information is available on the potential effectiveness of a hybrid barrier with several of the 

numerically dominant species at Harbor. Given that Alosids absent from the fish assemblage 

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

impingement mortality reduction standard and thus these types of barriers were removed from 

further consideration at Harbor. 

The existing intake at Harbor incorporate 3/8 in. square mesh traveling water screens that would 

be relatively easy to modify for installation of Ristroph screens. Ristroph screens are very 

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

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

screens have the potential to meet both standards, while coarse-mesh Ristroph screens may meet 
27

only the impingement morality standard. In addition, Ristroph screens are designed for 

continuous operation to minimize impingement duration. Continuous rotation along with the 

associated spraywashes provides 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 can be 

considered a viable alternative for reducing both IM&E. 

If only the entrainment standard needs to be met at Harbor fine mesh screen overlays could be 

used. These screens would be more cost effective than Ristroph screens as they would use the 

existing traveling water screens modified to accept a fine mesh screen material. However, these 

screens would not include the Ristroph fish handling and return components. Fine mesh 

traveling screens would meet the word of the Rule by significantly reducing entrainment 

numbers. Impingement mortality of entrainable organisms off of fine mesh traveling screens, 

however, are expected to be near 100%, and would, therefore have no net benefit. The Team 

does not expect CalEPA would accept changing an entrainment issue into and impingement 

issue. As a result fine mesh traveling screens are not considered a viable option for Harbor. 

Modification of the screenhouse to incorporate physical barriers or other diversion systems to 

prevent entrainment and impingement mortality would be difficult. Rotary drum screens and 

porous dikes require a much larger area than conventional traveling screens because of the lower 

design velocity. Rotary drum screens are typically installed in channels where water elevations 

are relatively constant and water depths are less than 12 ft, which is less than the water depth 

near the Harbor intake. Bar rack barriers are typically designed to have spacing greater than 1 in. 

and would not be effective in preventing the entrainment of early life stages. They may, 

however, be effective at reducing impingement. 

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

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

screens offer the potential to effectively divert most species by using smaller structures than the 

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

However, the MIS has not been shown to protect larval fish, and the Eicher screen is designed 

for installation in hydroelectric project penstocks. Therefore, these diversion technologies are 

not applicable to Harbor where impingement and entrainment are both of concern. 

The existing intake could be modified to incorporate cylindrical wedge wire screens, thus 

providing this technology with an engineering advantage over the porous dike, infiltration intake, 

and bar rack barriers (Table 3-1). Wedge wire screens also have cleaning features that give them 

an advantage over other fixed screens and barrier nets that are more difficult to maintain. This 

cleaning feature requires the presence of a sweeping current to be effective. Cylindrical wedge 

wire screens have a biological advantage in that they can exclude more life stages from intake 

water than conventional screens and bar racks. For this reason, wedge wire screens have been 

included in the preliminary evaluation for Harbor. 

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

screens. The AFB has an engineering advantage over barrier nets relative to cleaning (Table 

3-1). An AFB has two layers of material with an air purge system installed between the layers to 
28

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

impinged fish larvae and other non-motile life stages. The flow approaching an AFB is currently 

limited to10 gpm/ft2. Harbor would require about 7,500 ft2 of AFB to achieve this velocity. An 

AFB at Harbor would have to be approximately 225ft long, assuming a 33 ft average low water 

depth in front of the intake structure. Placing an AFB in the ILAH would interfere with shipping 

activities. Therefore, an AFB is not considered a viable alternative for preliminary evaluation for 

Harbor. 

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

cleaning, and are considered experimental for reducing entrainment at this time. However, 

coarse mesh nets could reduce impingement if they were installed in a low velocity zone and 

periodically cleaned to remove debris accumulation and biofouling growth. A barrier net at 

Harbor, however, would have to be installed in the ILAHC and would interfere with shipping in 

the channel. Additionally the design through-screen velocity of the existing traveling water 

screens appears to be less than 0.5 ft/sec, therefore automatically meeting the IM performance 

standard via Compliance Alternative 1. A barrier net is therefore not considered a viable 

alternative for preliminary evaluation at Harbor. 

The preliminary screening of intake technologies available for fish protection (Table 3-1) 

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

impingement mortality and entrainment at Harbor: 

• Expanded intakes with fine mesh4

 Ristroph screens 

• Wedge wire screens with 0.5 mm openings 

No technologies were evaluated to reduce only IM as Harbor should already meat the IM 

standard by having design through-screen velocities of less that 0.5 ft/sec 

The two selected alternative technologies have proven biological effectiveness and have 

advantages over other concepts, as presented in Table 3-1. All of these concepts have been 

previously developed to a level such that a conceptual design could be prepared for possible 

application of the technology at Harbor subsequent to this study. Therefore, these two 

alternatives have been carried forward to a preliminary evaluation, as presented in Section 4. In 

addition to these CWIS technology alternatives, flow reduction options that are considered to 

have the potential for application at Harbor to reduce entrainment are discussed in Section 3.3. 

3.3 Reduced Flow Alternatives Selected 

Two flow reduction options have been identified to reduce entrainment and, to a lesser extent, 

impingement at Harbor: 

 

4 The term “fine mesh,” as used in this document, refers to 0.5 mm (0.02 in.) square woven mesh. 
29

• Existing reduced flow operation 

• Install an additional closed-loop cooling system 

Harbor currently has only one unit, Unit 5 operating, with once-through cooling. Unit 5 operates 

off of waste heat from Units 1 & 2. Unit 3 and 4 have been retired and Units 10-14 are simple 

cycle turbines with cooling towers. Designing Units 1, 2 & 10-14 without once-through cooling 

may already result in a reduction in flow from a hypothetical baseline with all units operating as 

once-through that will meet the entrainment reduction standard. However, closed-cycle cooling 

could provide an even greater reduction in entrainment than the current plant design. 

Mechanical or natural draft wet towers would require less 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 than a wet 

mechanical draft tower. However, wet mechanical draft tower generally have less aesthetic and 

air quality impacts than natural draft wet towers. The area surrounding Harbor is heavily 

industrialized and would probably not be affected by compromised air quality, the site is 

however located near the city of Los Angeles. Since aesthetics and air quality issues would 

probably be greater for natural draft towers than for mechanical draft towers, wet mechanical 

draft towers were chosen as the closed-cycle cooling system option for preliminary evaluation. 
30

Table 3-1 Initial Screening of Fish Protection Alternatives at Harbor 

Concept 

Biological 

Effectiveness 

Proven 

Engineering 

Alternative 

Available 

Advantages 

Over Other 

Concepts 

Potential for 

Application at 

Harbor 

Behavioral Barriers 

 

Sound Yes Yes No No 

Infrasound No Yes Yes No 

Strobe Lights Yes Yes No No 

Mercury Lights No Yes Yes No 

Chemicals No No No No 

Electric Screens No Yes No No 

Air Bubble Curtain Yes Yes No No 

Water Jet Curtain No Yes No No 

Hanging Chains No Yes No No 

Visual Keys No Yes No No 

Hybrid Barriers (e.g. strobe light / air 

bubble curtain) No No No No 

 

Physical Barriers 

 

Fixed Screens Yes Yes No No 

Traveling Water Screens Yes Yes No No 

Rotary Drum Screens Yes Yes No No 

Barrier Net Yes No No No 

Bar Rack Barrier Yes Yes No No 

Infiltration Intakes Yes Yes No No 

Porous Dike Yes Yes No No 

Aquatic Filter Barrier Yes Yes No No 

Cylindrical Wedge Wire Screen 

Intakes Yes Yes Yes Yes 
31

Table 3-1 (continued) 

Concept 

Biological 

Effectiveness 

Proven 

Engineering 

Alternative 

Available 

Advantages 

Over Other 

Concepts 

Potential for 

Application at 

Harbor 

Collection Systems 

 

Modified Traveling (Ristroph) Screens Yes Yes Yes Yes 

Fish Pumps Yes Yes No No 

 

Diversion Systems 

 

Louvers/Angled Bar Racks Yes Yes No No 

Angled Screens (Fixed or Traveling) Yes Yes No No 

Angled Rotary Drum Screens Yes Yes No No 

Inclined Plane Screens No Yes No No 

Eicher Screen Yes Yes No No 

Modular Inclined Screens Yes Yes No No 

Submerged Traveling Screens No Yes No No 

 

Modifications to Reduce Intake Flow 

Modified Pump Operation Yes Yes No No 

Install Variable Speed Drivers Yes Yes No No 

Install Closed-Loop Cooling System 

(Mechanical & Natural Draft and Dry 

Cooling Towers) 

Yes Yes Yes Yes 

32

Section 4 

DETAILED EVALUATION OF ALTERNATIVES 

4.1 Assessment of Alternatives with Potential for Application 

Based on the screening of intake technologies and flow reduction options presented in Section 3, 

two alternatives utilizing intake technologies for fish protection and two flow reduction options 

were selected as having potential for effective application at Harbor. The alternatives selected 

for more detailed evaluation are: 

 Alternative 1 – Add Fine Mesh Ristroph Screens to the Existing Screenhouse 

 Alternative 2 – Retrofit Intake with 0.5 mm Wedge Wire Screens 

Alternative 3 – Existing Reduced Flow Operation 

Alternative 4 – Retrofit Plant with Closed-Cycle Cooling System 

Preliminary conceptual designs were prepared for each of these alternatives to serve as a basis 

for evaluation and cost estimates. The following sections present for each option: (1) the 

technical considerations associated with the design, installation, operation, and maintenance, (2) 

estimated construction costs and operating and maintenance costs, including replacement power, 

and (3) estimated biological effectiveness. 

4.2 Add Fine Mesh Ristroph Screens to the Existing Screenhouse 

Fine mesh Ristroph screens could be used to reduce both IM&E at Harbor. The velocity 

approaching the existing traveling screens was calculated to be 0.2 ft/sec, significantly less than 

0.5 ft/sec, which is the design velocity Alden considers to be sufficiently protective of fish eggs 

and larvae. Therefore, the existing screenbays could be used and the screenhouse would not 

have to be expanded to lower the approach velocities to 0.5 ft/sec. This velocity assumes that 

equal flow is going through all four of the operating screens. If in fact flow is only passing 

through two of the operating traveling screens the velocity would be about 0.4 ft/sec, which is 

still less than the Alden design value. 

The screen baskets would have 0.5 mm mesh. Each screen basket would have a fish bucket to 

hold collected organisms in about 2 in. of water while they are lifted to the fish recovery system. 

A low pressure spray (10 psig) would be used to gently remove the fish from the fish holding 

buckets into a separate fish sluice that would return fish to the West Basin. A conventional high 

pressure wash would then remove debris into a separate debris sluice. A section of a typical 

Ristroph screen is shown on Figure 4-1. 

New fish and debris troughs would be mounted above deck level on the descending side of the 

screens. These troughs would combine into a single trough and flow into the West Basin of the 

ILAH outside of the CWIS’ zone of influence. This trough would be about 2,500 ft long. The 
33

existing screenwash pumps would be used to provide water for the high pressure spraywash 

headers. New screenwash pumps would be installed for the low pressure spraywash headers. 

Removal of the existing traveling water screens and installation of the new Ristroph screens 

would require about two weeks per screen to remove the original screen, install the new screens, 

and complete mechanical and electrical work. The new fish and debris trough could be built 

simultaneously to the installation of the screens. These CWIS modifications would not require 

Harbor to be shutdown during the construction. 

Operating and maintenance demands for the new screenhouse would be greater than the O&M 

requirements for the existing CWIS. Continuous operation of the fine mesh screens and 

operation of the screenwash pumps would require 1,050 MWh per year. 

Fine mesh screens at Harbor would decrease the entrainment of larval fish through the 

circulating water system. The effectiveness of this system would depend on the species of larvae 

and eggs currently present near the Harbor CWISs. Retention can be estimated using the head 

capsule depth (HCD) (the widest non-compressible portion of the larval body). When head 

capsules are larger than the nominal opening size of a fine mesh screen, they will not be 

entrained. With larvae, the orientation of the organism at the time they encounter the screen will 

also influence the likelihood of being retained. Based on the entrainment sampling conducted at 

Harbor in 1978-79, any fish protection technology that substantially reduces the entrainment of 

sciaenid eggs, larval gobies, and larval anchovies should provide sufficient protection to the 

potentially entrainable organisms at Harbor to meet the entrainment standard. 

A second factor to consider with fine mesh screens is that fish that were previously entrained 

would be impinged. These screens are beneficial from an organism protection viewpoint only if 

impingement survival for important species and life stages is relatively high and exceeds 

entrainment survival levels. Post-impingement survival of fish is very species-specific. For 

example, past studies have shown that other gobies have had variable survival when exposed to 

traveling screens. Reported extended survival of naked goby (Gobiosoma bosc) exposed to a 

standard screen was 18% (Oyster Creek, juveniles, Tatham et al. 1978) whereas the same species 

and life stage exposed to Ristroph screens at Roseton Station had 100% survival. Reported 

survival of another goby species, the seaboard goby (Gobiosoma ginsburgi), was 74.5% when 

exposed to fine-mesh Ristroph screens (Oyster Creek, juveniles, Davis et al. 1988). In contrast, 

engraulids (bay anchovy) have relatively low survival following impingement on fine mesh 

screens. Although there is no post-impingement survival data available for white croaker, 

extended survival of other juvenile Sciaenids (excluding freshwater drum) is moderate to high. 

The range of survival extends from 0 to 100% with a mean reported survival of 66.6% with a 

standard error of 4.2. 

Use of fine mesh screens is therefore a tradeoff. Some species and life stages may benefit, while 

others may experience greater mortality than under existing conditions. From a compliance 

standpoint, the Rule considers entrainable organisms to be those that will pass through a standard 

3/8 in. mesh. After a fine mesh screen is added to an intake, those organisms that were 

previously entrained are still considered to be “entrainable.” As such, the mortality of these 

impinged “entrainable” organisms is not considered. The Rule remains unclear about whether 
34

the survival of organisms prevented from entrainment should be a concern. The Team believes 

that since EPA implies that impingement and entrainment are potential causes of AEI, 

entrainment survival must be considered. 

4.3 Retrofit Intake with 0.5 mm Wedge Wire Screens 

Fine mesh cylindrical wedge wire screens could be installed to reduce fish entrainment and 

impingement. Cooling water would be conveyed through submerged, cylindrical wedge wire 

screens mounted on a bulkhead wall in front of the existing CWIS. The bulkhead would be 

constructed to form a common plenum in front of the existing intakes. The existing trash racks 

and traveling water screens would no longer be needed with the option. 

This bulkhead would be placed about 30 ft in front of the existing CWIS, within the area 

enclosed by the pile dolphins, as shown on Figure 4-2. The screens would be mounted on this 

wall in three rows of 10 screens. The minimum water depth at the screens has been assumed to 

be approximately 35 ft during mean lower low water levels. If the actual water depth in the 

vicinity of the screens is less than 28.5 ft, there would not be sufficient water depth for this 

configuration. 

The screens would have a 0.5 mm screen slot size and would be designed for a maximum slot 

velocity of 0.5 ft/sec. Thirty, T-36 screens, as shown on Figure 4-3, would be required to screen 

the entire facility flow. Each screen would be 3.0 ft in diameter and T-shaped, with an overall 

length of about 9.5 ft. Two screen sections, each about 3.0 ft long, would be located on each side 

of a 3.5 ft long T section. The outlet pipe would be 2.0 ft in diameter and located in the middle 

of the T section. The outlet of the T would be flanged for connection the bulkhead wall. 

An air backwash system, complete with necessary air compressors and controls, would be 

installed to clean the wedge wire screens. The air compressors and controls would be located in 

a new shelter near the existing CWIS. The air piping to each wedge wire screen would be 

installed along the top the bulkhead wall. The air backwash system could be an effective method 

for maintaining the wedge wire screens at Harbor in a clean condition. The effectiveness of this 

cleaning would be contingent on the local tidal currents ability to transport debris flushed away 

from the screens. Periodic manual cleaning for removal of biofouling agents would likely be 

necessary. 

Approach velocities at the wedge wire screens would be similar to currents in the area. The 

maximum through-slot velocity would not exceed 0.5 ft/sec. Therefore, the screens should be 

highly protective of juvenile and adult fish. Head losses through the screens should not exceed 1 

ft (assuming biofouling would not be a significant problem). Except for the slightly lower water 

level, flow characteristics in the existing screenbays would not change. Flow patterns to the 

pumps would not change from the existing conditions. 

Shutdown of unit during construction would not be necessary. Unit 5 could operate fully during 

construction of the concrete bulkhead wall, as long as a section of the wall was left open to allow 

flow to the screenhouse. Once the wall was completed the screens could be installed and made 

operational one at a time. 
35

Installation of the cylindrical wedge wire screens would eliminate the need for operation and 

maintenance of the existing traveling water screens. If the potential for wind-blown debris is 

high, then a roof could be installed over the plenum. Maintenance requirements for the 

circulating water pumps with the wedge wire screens in place would not change. Additional 

operation and maintenance efforts associated with the wedge wire screens would entail 

approximately 43 MWh per year. Facility personnel would be required to operate the air 

compressors and monitor backwashing operation to maintain the air supply equipment. 

Semiannual inspections by divers would be necessary to identify any damage or debris build up 

that could affect plant operations and to verify effective cleaning by the air backwash system. 

These inspections would take approximately 2 days using a three-man diving crew working from 

a workboat. 

Physical size and behavior impact the effectiveness of wedge wire screens to prevent the 

entrainment and impingement of the early life stages of fish. Physical exclusion of fish with fine 

mesh screens is achieved when the openings to the screen are smaller than the head capsule of 

the larvae being protected. Therefore, head capsule depth can be used to determine if larvae can 

fit though an opening of a certain size. The slotted wedge wire design is more conducive to fish 

passage than a woven mesh of the same nominal opening size. Unlike with fine mesh screens, 

however, hydraulic conditions in the vicinity of the wedge wire screens may stimulate rheotactic 

responses in the larvae causing them to swim away from the screens. Species-specific behavior 

will also impact the likelihood of entrainment and impingement. For example, Weisberg et al. 

(1984) observed that naked goby larvae were more susceptible to entrainment than bay anchovy, 

in part, due to their tendency to prefer structures. Gobies were observed swimming very close to 

the screens and feeding on detritus drawn towards the screens. 

This wedge wire screen option will meet the impingement mortality reduction standard, because 

the design through-screen velocity is 0.5 ft/sec. or less (Compliance Option 1). Their ability to 

meet the entrainment reduction standard will be based upon the results of verification monitoring 

required by the CDS. 

Recent laboratory evaluations of wedge wire screens indicate that 0.5 mm screens can be 

effective in reducing entrainment and impingement of larval fish and eggs (EPRI 2003b). With 

the exception of rainbow smelt, 0.5 mm wedge wire screens configured for slot velocities of 0.15 

m/sec, entrainment was 10.1% or less (alewife, winter flounder, white sucker, bluegill, striped 

bass, and yellow perch) when ambient currents were 0.15 m/sec or greater (EPRI 2003b). 

Rainbow smelt larval entrainment with a slot opening of 0.5 mm and slot velocity of 0.15 m/s 

was 75.0, 67.3, and 25.3% at channel velocities of 0.08, 0.15, and 0.30 m/s respectively. During 

the laboratory study, the eggs and larvae were released directly in front of the screens. 

Therefore, the entrainment rates observed are potentially higher than what would be expected in 

the field. Therefore, the screens, as designed, should be protective of fish at Harbor. 

4.4 Existing Operations 

Harbor currently has seven units in operation, only one requiring cooling water. Units 1&2 are 

combined cycle units, operating off of the waste heat from Unit 5 and do not require any 

additional cooling water. Unit 1&2 produce a combined total of 160 MW. Unit 5 is a 75 MW, 
36

steam turbine with once through cooling. Units 10-14 are gas turbines with cooling towers and 

have a combined output of 240 MW. The total combined unit output of Harbor is 473 MW. 

Assuming that flow is roughly proportion to generation, Alden believes that current facility 

operations reduce flow by 84% from a hypothetical baseline flow with all units operating with 

once-through cooling. If only Units 1, 2 & 5, the units that make up the Harbor Steam Plant, are 

considered, Unit 5 flow would be about 32% of the total three unit flow, if all unit have oncethrough cooling, thereby reducing entrainment by 68%. 

The CWIS and screenhouse at Harbor were designed for five units with once-through cooling. 

Since only Unit 5 currently withdraws water through the CWIS, the flow through the CWIS has 

been greatly reduced from its original design flow. Under current operations only one 

circulating water pump is used during normal operation, with the second pump held on reserve 

for use if there are problems with the unit (e.g. vacuum problems). Based on one pump 

operation and flow through four screenbays, the through-screen velocity was estimated to be 

about 0.4 ft/sec . This velocity will meet the IM standard via Compliance Alternative 1 (0.5 

ft/sec through-screen velocity). 

Continuing current operations would entail no construction activities or related outages. 

Operation and maintenance may increase as four traveling water screens would have to be used 

regularly. Maintaining current operating procedures with the existing intake structure would not 

create any additional adverse air, water, land, or energy resource impacts on the environment. 

4.5 Retrofit Plant with Closed-Cycle Cooling System 

Retrofitting the once-through cooling water system with a closed-cycle cooling system would 

reduce water withdrawal from the ILAHC for Harbor’s cooling systems. The average amount of 

make-up water for cooling towers would be approximately 5 cfs (about 3.0% of the once-through 

cooling water requirement), with a commensurate reduction in organism entrainment. As Harbor 

would be withdrawing saline water the actual amount of water needed may be higher depending 

on the cycles or concentration required. Reclaimed water from a nearby LA City Publicly 

Owned Treatment Works (POTW) could also be used to provide makeup water for cooling 

towers. An evaluation of cooling tower costs for retrofitting existing power facilities was 

provided in EPRI’s report entitled “Cooling System Retrofit Costs Analysis” prepared in July 

2002. This report was prepared in response to the EPA Rulemaking. This study was conducted 

to provide generalized methods and supporting data for estimating the cost of retrofitting existing 

facilities with re-circulating systems (EPRI 2002a). 

The EPRI report (2002a) developed the likely costs for “all cooling towers.” To develop these 

costs, three assumptions were made: 

1. The addition of a cooling tower would connect to the existing condenser so circulating 

water rates would not change. 

2. Portions of the existing condenser conduit systems could be used, even though some 

modifications may be required. 
37

3. The cost methodology is based on new facilities and was adjusted using multiplying 

factors to determine the cost of retrofitting an existing facility. 

Using these assumptions, the costs for retrofitting a cooling tower to an existing facility were 

broken down into easy, average, and difficult retrofitting costs. These three cost levels are based 

mainly on site-specific factors (EPRI 2002a). 

A mechanical or natural draft cooling tower could be retrofitted to meet the cooling requirements 

of Harbor. For the purpose of this evaluation, Alden has assumed that a mechanical draft tower 

would be installed at the site. Because Harbor is located near Los Angeles, plume abatement 

measures may be needed, and therefore the site has been classified as a difficult site to install 

cooling towers. This cost does not take into consideration costs associated with piping reclaimed 

water to the facility. 

Most of the condenser and cooling system components inside the turbine building would remain 

intact and would use approximately the same condenser flows. Cooling water, which is currently 

discharged into the West Basin, would be redirected into a wet pit pump structure where booster 

pumps would convey cooling water to the cooling tower spray deck and back to the existing 

intakes. There, the existing circulating water pumps would convey the cooling water through the 

condensers similar to the existing once-through system. The existing CWISs would be isolated 

from the ILAHC by putting stoplogs in the CWIS. New, smaller pumps would be installed in the 

CWIS to supply makeup water for the closed-cycle cooling system. 

Most of the construction efforts on the cooling tower would be independent of the existing 

circulating water system and would not affect facility operations. However, replacement power 

would be required to implement the intake modifications and the final circulating water pipe 

modifications. These efforts would require Units 1, 2 &5 to be shut down for about 6 months, 

which could amount to a loss in generation of about 329,214 MWh. 

The mechanical draft cooling tower would require approximately 1.2% of the total plant output 

for auxiliary power (EPRI 2002a). The extra power would be required to operate the additional 

cooling water supply pumps for the tower, the tower fans, the blowdown facility equipment, and 

the makeup water pumps. Total auxiliary power would amount to 2,503 MWh per year. Since 

the temperature of the cold water produced by the tower would be proportional to approach 

temperature (local wet bulb temperature), the closed-cycle system would produce warmer water 

than the current once-through cooling water. All retrofitted closed-cycle cooling system 

alternatives would cause a reduction in net generation and a corresponding increase in the heat 

rate, except for periods when the turbine output is limited by high backpressures. The higher 

water temperatures at the condenser inlet would reduce facility output by 1% of total facility 

capacity or about 2,107 MWh during the year (EPRI 2002a). The net loss of salable power 

would be about 4,610 MWh per year. 

Annual maintenance is necessary on the mechanical and electrical components of a mechanical 

draft tower and the other pumping components for a closed-loop cooling water system. Pumps, 

fans, motors, controls, fill sections, support structures, and the tower basin and hardware all 
38

require periodic inspections and maintenance. The EPRI study indicates that the operating and 

maintenance costs for a cooling tower retrofit would be 2% of the total construction costs. 
39

Figure 4-1 Typical Ristroph Screen – Section 
40 

Figure 4-2 0.5 mm Wedge Wire — Plan 
41 

Figure 4-3 0.5 mm Wedge Wire — Section 
42

Section 5 

RESTORATION AS A 316(B) COMPLIANCE OPTION AT LADWP’S HARBOR 

GENERATING STATIONS 

The EPA final Phase II Rule also provides that applicants may use restoration measures in 

addition to, or in lieu of, technology measures to meet performance standards or in establishing 

best technology available (BTA) on a site-specific basis. Specifically, EPA’s final Phase II Rule 

states the following requirement relative to the use of the restoration approach: 

Facilities that propose to use restoration measures must demonstrate to the permitting 

authority that they evaluated the use of design and construction technologies and 

operational measures and determined that the use of restoration measures is 

appropriate because meeting the applicable performance standards or requirements 

through the use of other technologies is less feasible, less cost-effective, or less 

environmentally desirable than meeting the standards in whole or in part through the 

use of restoration measures. 

The basic philosophy of restoration is mitigation of fish losses at a CWIS via: 

• Direct supplementation of a “species of concern” (stocking) potentially impacted by the 

CWIS; or 

• Provision, protection, or restoration of habitat that “produces” fish and thereby replaces those 

lost due to impingement and entrainment mortality. 

Restoration efforts may be “in-kind” or “out-of-kind.” “In-kind” restoration directly replaces 

(either via stocking or habitat) the fish and shellfish species that are lost due to impingement 

mortality and entrainment. “Out-of-kind” restoration replaces the fish and shellfish species lost 

with a different species mix as determined in consultation with the permitting authority and fish 

and wildlife resource agencies and tribes. 

Restoration is a voluntary action offered by the applicant (LADWP) — the permitting agency or 

any other federal or state resource agency cannot request restoration as a mitigation approach. 

The following subsections discuss the basic philosophy of restoration, the general types of 

restoration projects that a facility may develop the role of restoration in EPA’s Phase II Rule, and 

filing requirements if the facility pursues this option. The review also includes potential specific 

restoration measures for consideration by LADWP for proposal to California’s Environmental 

Protection Agency (CEPA) — State Water Resources Control Board (specifically, the Los 

Angeles Regional Water Quality Control Board or RWQCB). Restoration is state (permit 

authority) specific. The following discussion, therefore, applies to all of LADWP’s power plants 

in California (Haynes, Harbor and Scattergood). 

5.1 What Are the Implications of the Recent Court Ruling Regarding the Use of 

Restoration in the EPA Phase I Rule to Their Use in Phase II? 

On February 3, 2004, the Second Circuit of the U.S. Court of Appeals, following consideration 

of the Riverkeeper Alliance petition of the EPA Phase I Rule (FR 66(No. 243), December 18, 
43

2001), found that EPA exceeded its authority relative to allowing compliance with §316(b) 

through restoration methods. As a result of this finding, the Court remanded that aspect of the 

Phase I Rule. The Court’s decision, however, was clearly limited to Phase I by the following 

explicit footnote: 

In remarking that one standard is applicable to new and existing structures, [the members of the 

Court] stress that this is one reasonable reading of the statutory language. In no way [does the 

Court] mean to predetermine the factors and standard applicable to the Phases II and III of the 

rulemaking. 

Despite the Court’s ruling prior to the EPA Administrator’s signing of the Phase II Rule, EPA 

decided to retain provision for restoration as discussed herein. To address many of the Court’s 

concerns, however, EPA strengthened the Rule’s language relative to restoration methods and 

explicitly noted the restoration approach as a cooling water intake structure “technology” option. 

Furthermore, EPA discussed how inclusion of this “technology” option provides the necessary 

flexibility that existing facilities will need to meet the performance requirements of the final 

Phase II Rule. 

Following release of the final EPA Phase II Rule and despite EPA’s modified language relative 

to restoration, the Riverkeeper Alliance clearly signaled its intent to again litigate the Phase II 

restoration provisions. Based on the fact that it took the Court nearly 2 years to reach its 

decision relative to Phase I, we can reasonably expect a similar time period to pass before the 

Court renders a decision on the EPA Phase II provisions for restoration methods. 

The Team offers no prediction on the results of the expected litigation other than to note that 

major investment in a restoration compliance strategy is an at risk approach. This risk, 

however, should not preclude consideration of restoration measures as discussed herein, 

including preliminary planning for restoration implementation. Such consideration and planning 

will allow for effective implementation of restoration measures by SCE&G as a compliance 

approach should the Court reject the Riverkeeper Alliance’s expected petition. 

5.2 Why Should LADWP Consider Restoration? 

Essentially, there are three reasons for considering a restoration approach: 

1. Other technologies and operational measures, as noted by EPA, are less feasible, less costeffective, or less environmentally desirable. 

2. Restoration is scalable according to the performance requirement needed, unlike technologies 

that generally have a theoretical fixed level of performance. A facility can use a restoration 

project, therefore, to make up the difference when a technology only achieves some of the 

performance required.5

 

5

 For example, suppose a specific technology only achieves a 50% reduction in intake entrainment. A restoration 

project can be implemented to attain the remaining 10%+ reduction needed to meet the EPA’s proposed 60–90% 

entrainment reduction performance standard. Also, assume a site-specific performance standard much lower than 
44

3. Direct environmental and public relations benefits associated with restoration projects that 

the facility will not likely attain via an intake technology. 

Minimizing “adverse environmental impact” (AEI), as measured at the population level, is not an 

explicit objective of the final Phase II Rule. In other words, direct reductions in impingement 

mortality and entrainment may not result in any type of net benefit to fish populations. 

Restoration measures, however, when properly designed and maintained, can offer direct 

benefits to the targeted species. Furthermore, ancillary benefits, when the restoration measure is 

habitat-based, can also be significant (e.g., riparian erosion control associated with wetland 

restoration) (EPRI 2003a). The public relations benefits mentioned above may be in accord with 

corporate environmental stewardship goals, making pursuit of restoration a worthy goal for this 

reason alone. 

Similarly, we must also ask, Why should LADWP not consider restoration? A key reason for 

possibly not pursuing the restoration option is that a restoration project may take several years, in 

some cases as many as 10 years, before it operates at a level equivalent to natural production. 

For some projects, like fish stocking, it must be a continuous process during the life of the plant. 

There are also no guarantees that for some restoration projects (e.g., fish passage), the “if you 

build it they will come” theory will apply. Long-term performance monitoring, many years 

longer than an intake technology would likely require, and other information requirements to 

address the uncertainties associated with restoration, may be burdensome and reasons for not 

considering the restoration option. Also, as previously noted, the recent Court ruling regards 

restoration in the Phase I Rule, and expected litigation over the restoration provisions in the 

Phase II Rule creates significant uncertainties relative to the legal standing of the restoration 

compliance option. 

5.3 Types of Restoration Applicable to §316(b) 

EPA does not specify the types of restoration measures that can be used. This lack of 

specification provides flexibility in developing/proposing a restoration approach. Restoration 

measures that have been used at other power stations to meet §316(b) requirements include: 

• Wetland restoration, e.g., Public Service Electric & Gas (PSEG) Delaware Bay wetland 

restoration program for the Salem Generating Station (Weinstein et al. 2001). See 

http://www.pseg.com/companies/nuclear/estuary/overview.html.

• Fish stocking, e.g., Mirant (formerly PEPCO) fish hatchery at the Chalk Point Station (Bailey 

et al. 2000); Exelon’s (formally Commonwealth Edison) walleye hatchery at Quad Cities 

Station on upper Mississippi River (LaJeone and Monzingo 2000); and Southern California 

Edison’s white sea bass hatchery implemented, in part, for fish losses at SONGS (see 

subsequent SCE Web site address). 

 

the EPA standards (e.g., a 25% reduction in impingement mortality rather than the required 80–95% standard) is 

established as a result of the outcome of one of the variance option tests. It may be much easier and a lower cost to 

scale a restoration project to this performance standard rather than install an intake technology. 
45

• Submerged aquatic vegetation (SAV) restoration, e.g., Southern California Edison’s kelp 

restoration for the San Onofre Nuclear Generating Station (Deysher et al. 2002). See 

http://www.sce.com/sc3/006_about_sce/006b_generation/006b1_songs/006b1c_env_prot/006b1c3_songs_miti/default.htm.

• Provision of fish passage (such as fish ladders or dam removal) at non-hydropower projects, 

e.g., PSEG fish ladders in Delaware Bay tributaries for the Salem Generating Station. See 

http://www.pseg.com/companies/nuclear/estuary/overview.html.

• Contribution to, or maintenance of, a restoration fund, e.g., Duke Energy North America’s 

contribution ($7 million) to the Elkhorn Slough Foundation to mitigate for 316(b)-related 

impacts associated with the re-powering of the Moss Landing Station on Elkhorn Slough 

near Monterrey Bay, California. See http://www.dukeenergy.com/businesses/plants/own/us/western/morrobay/reports/. 

• Water quality improvements, e.g., riparian area protection or implementation of non-point 

source best management practices, that minimize sediment/pollutant runoff, thereby resulting 

in fishery habitat improvements as well as practices that increase dissolved oxygen content in 

waterbodies, thereby increasing available habitat for fish spawning and survival. While this 

approach is plausible, there are no known existing examples of such a 316(a & b) restoration 

project. 

We describe the advantages and disadvantages, design considerations, and approximate unit 

costs of each of these restoration options in detail in EPRI (2003a). 

5.4 Role of Restoration in the EPA Phase II Rule 

EPA’s final Phase II Rule provides that a facility can voluntarily implement restoration measures 

in lieu of, or in combination with, reductions in impingement mortality and entrainment. If a 

facility uses restoration measures, it must demonstrate to the permitting agency that the 

performance of the restoration measures (the production of fish and shellfish in the facility’s 

waterbody or watershed, including the maintenance of community structure and function) is 

substantially similar to that which it would have achieved if the facility met the standards with 

onsite technology and/or operational measures. The role of restoration in the final Rule is to 

provide additional flexibility to both permitting authorities and facilities in complying with the 

Rule by eliminating or significantly offsetting what are, in EPA’s opinion, the AEI caused by the 

operation of a CWIS. EPA believes that restoration measures, such as fish stocking and wetland 

restoration, are “technologies” within the meaning of that term as used in §316(b) and, as such, 

are an appropriate means for meeting technology-based performance standards. 

As previously discussed, facilities that propose to use restoration measures must demonstrate to 

the permitting authority that they evaluated the use of technologies and operational measures and 

determined that the use of restoration measures is appropriate because meeting the applicable 

performance standards through the use of other technologies is less feasible, less cost-effective, 

or less environmentally desirable than meeting the standards in whole or in part through the use 

of restoration measures. Facilities must also demonstrate that the restoration measures they plan 

to implement, alone or in combination with technologies and/or operational measures, will 

produce ecological benefits (production of fish and shellfish) at a level that is substantially 

similar to the level that a facility would achieve through compliance with the applicable 
46

performance standards or alternative site-specific requirements that a facility attained from 

results of either the Cost-Cost test or Cost-Benefit test. In other words, restoration measures 

must replace the fish and shellfish lost to impingement mortality and entrainment, either as a 

substitute or as a supplement to reducing impingement mortality and entrainment through 

technologies and/or operational measures. The species makeup of the replacement fish and 

shellfish need not be exactly the same as that of the impingement mortality and entrainment 

losses (i.e., “out-of-kind” restoration). However, the facility must demonstrate to the permitting 

authority that the net effect of the restoration project will be the production of fish and shellfish 

in the waterbody that is “substantially similar” to that which would result from meeting the 

performance standards via the technology approach. 

The final Rule also requires that a facility use an adaptive management method for implementing 

restoration measures because the facility must regularly monitor the performance of restoration 

projects and potentially adjust them to ensure the projects achieve their intended objectives. The 

final Rule also requires that restoration projects that replace the lost fish and shellfish with a 

different species mix (“out-of-kind” restoration) be based on a watershed approach to restoration 

planning. The boundaries of a “watershed” should be guided by the cataloging unit of the 

“Hydrologic Unit Map of the U.S.,” although it may be appropriate to use another watershed or 

waterbody classification system developed at the state or local level if such a system compares 

favorably in level of detail. EPA notes as an example, in coastal systems that support migratory 

fish, a coastal waterbody that transects a number of watersheds may be the most appropriate unit 

for restoration planning. 

Restoration must address the “species of concern” identified by the permit director in 

consultation with federal, state, and tribal fish and wildlife management agencies that have 

responsibility for aquatic species potentially affected by a facility’s CWIS. In California, this 

involves the federal Fish & Wildlife Service (FWS) and the National Marine Fisheries Service 

(NMFS), the state’s Regional Water Quality Control Board (RWQCB), California Energy 

Commission (CEC), and California Department of Fish & Game (CDFG). Native American 

Tribes in California will also have a role in identifying “species of concern” and commenting on 

potential restoration projects. While the final Phase II Rule does not require collaboration with 

local non-governmental agencies, it is likely that RWQCB and other resource agencies would 

require or strongly encourage such collaboration. “Species of concern” is a new term specific to 

these regulations. The fact that a CWIS may only potentially have an impact on such species 

offers tremendous flexibility toward development of restoration measures. This is particularly 

relevant to endangered, threatened, and rare species (federal and state) that characteristically are 

not impacted by a CWIS (e.g., California green sturgeon, protected California rockfish species, 

southern California steelhead), but may, however, be of high restoration interest to the federal, 

state, and tribal agencies. 

EPA strongly encourages facilities with an interest in pursuing a restoration approach to initiate 

consultation with the fish and wildlife management agencies to: 

• Identify the “species of concern” 

• Identify the current status of “species of concern” located within the subject waterbody and 

provide general life history for those species, including preferred habitats for all life stages 
47

• Identify potential threats to “species of concern” found within the waterbody other than the 

CWIS (i.e., identify all additional stressors for the species of concern), appropriate 

restoration methods, and monitoring requirements to assess the overall effectiveness of 

proposed restoration projects. 

EPA stresses the importance of consultation because it believes that natural resource 

management agencies typically have the most accurate information available and thus are most 

knowledgeable about the status of the aquatic resource they manage. 

5.5 Potential Restoration Measures for LADWP’s Haynes, Harbor, and Scattergood 

Generating Stations 

LADWP may wish to consider the following example restoration projects6 to attain the 

impingement mortality (and, if applicable, entrainment) reduction performance standard or as 

part of a site-specific standard developed by the permit director. These projects are listed 

because of their known interest to fish and wildlife agencies in California and because design 

and implementation information is readily available: 

NOTE: Many of the following programs are voluntary collaborative efforts. They are not 

designed as regulatory option programs and some may not be directly receptive to 

regulatory involvement.7

 The programs do, however, offer valuable contacts for 

restoration information or for evaluating potential restoration approaches that are 

volunteered to meet the requirements of EPA’s Phase II §316(b) rule. 

 

6 Projects listed are examples. Opportunities for creative restoration projects are unlimited and depend upon 

corporate interests and negotiations with state and federal resource agencies. 

7 Currently, there is only one restoration-based regulatory program in the U.S., NOAA’s Restoration Center Damage 

Assessment and Restoration Program (DARP) (see 

http://www.nmfs.noaa.gov/habitat/restoration/projects_programs/darp/index.html). NOAA established DARP in 1990 to 

fulfill natural resource trustee responsibilities assigned in the Clean Water Act (CWA), the Superfund Act, the Oil 

Pollution Act of 1990 (OPA), and the National Marine Sanctuaries Act (NMSA). As a natural resource trustee, 

NOAA acts on behalf of the public to restore resources injured by oil spills, releases of other hazardous substances, 

and vessel groundings. DARP collaborates with other federal, state, and tribal natural resource trustees in: 

• Assessing and quantifying injuries to natural resources 

• Seeking damages for those injuries 

• Implementing restoration actions 

• Monitoring progress to ensure restoration goals are met 

It is possible that a similar federal program could develop in the future to support other Clean Water Act regulatory 

efforts such as those involved with §316(b) should there be sufficient demand for a consistent process. 
48

Fish stocking.8

 This involves the direct supplementation (stocking) of a fish species of concern 

to aid restoration efforts for that species. A facility generally pursues restoration stocking (as 

opposed to recreational gamefish stocking) where the species of interest has been completely 

extirpated or where associated habitat restoration is unlikely to contribute to stock restoration. 

For example, the Georgia Department of Natural Resources (GDNR), following 6 years of study, 

recently initiated a long-term effort to restore lake sturgeon to the Coosa River system in 

Georgia/Alabama. This species is listed as threatened throughout the U.S. and has disappeared 

completely from much of its original range, including the Coosa River. Through a collaborative 

effort between several state and federal agencies, GDNR released 1,100 fingerlings to the Coosa 

River in December 2002 as the first step toward returning lake sturgeon to a healthy, selfsustained population in the river (see 

http://georgiawildlife.dnr.state.ga.us/content/displaycontent.asp?txtDocument=305). A similar program may be of 

interest in California, particularly for the southern steelhead salmon or coastal rockfish (Sebastes

spp.), both of which are federal and state listed endangered and threatened species along the 

California coast (see http://ecos.fws.gov/tess_public/TESSWebpageUsaLists?state=CA). CDFG and RWQCB 

(and USFWS/NMFS) may support LADWP’s participation in a program to restore rare, 

threatened, and endangered fish to native habitat. Mirant Mid-Atlantic Inc. currently raises and 

stocks Atlantic sturgeon at its Chalk Point Hatchery Facility on the Patuxent River for the State 

of Maryland, Department of Environmental Protection. American shad restoration to the 

Susquehanna River basin in Maryland/Pennsylvania has been accomplished in part via stocking 

of juvenile shad and via provision of fish passage (St. Pierre 2003; Hendricks 1995). LADWP 

could also combine restoration stocking (e.g., for southern steelhead) with provision of fish 

passage (i.e., dam removal or fish ladders). We discuss this form of restoration further below. 

Fish stocking program support could be via hatchery operation developed on or off plant 

property (e.g., SCE funds the operation of a fish hatchery in Carlsbad, CA, for culturing and 

stocking California sea bass. See 

http://www.sce.com/sc3/006_about_sce/006b_generation/006b1_songs/006b1c_env_prot/006b1c3_songs_miti/default.htm.) 

LADWP would operate and maintain such a hatchery under state and federal oversight. 

Alternatively, LADWP could possibly negotiate a direct annual contribution of funds to a state 

and federal hatchery supplementation program or a private foundation. For example, the 

Hubbs/Sea World Research Institute operates the SCE fish hatchery for SONGS mitigation. 

While hatchery or stock supplementation programs can be controversial due to concerns over 

protection of natural genetic integrity, California resource agencies, based on their approval and 

development of SCE’s SONGS Mitigation Project, supported stocking as compensation for fish 

losses. CDFG and NMFS also have a long-term fish hatchery program to support maintenance 

and restoration of anadromous salmonids in California coastal rivers (CDFG/NMFS 2001). 

California resource agencies’ experience with hatchery supplementation may mean that they 

 

8

 While forage species (e.g., gobies, anchovies, sardines) are the most common species impacted at LADWP’s 

power plants, stocking of these species to compensate for the losses would not be of interest to any of the federal 

and state fish and wildlife agencies. The objective of a supplementation program would be to identify a “species of 

concern” the stocking of which would compensate (be “comparable to, or substantially similar to”) for the 

production foregone as measured by a gamefish’s consumption (e.g., X northern anchovy are equivalent in energy or 

food consumption to Y white sea bass or other recreational or commercial fish of concern). This is the approach 

used by Potomac Electric Power Company for estimating annual hatchery production of striped bass to compensate 

for bay anchovy (a forage species) losses at its Chalk Point Generating Station on the Patuxent River in Maryland. 
49

could be receptive to a hatchery program established by LADWP as compensation for 

impingement and entrainment losses at LADWP power plants in southern California. For 

example, when operating at design capacity, the SCE-funded hatchery is expected to exceed 

compensation for the total SONGS fish losses estimated by an expert panel created by the 

California Coastal Commission. 

For approximate cost references, SCE provided $4.7 million in funding for the white sea bass 

hatchery which began operation in late 1996. Similarly, the Potomac Electric Power Company 

(PEPCO) established an aquaculture facility at their Chalk Point Station at a capital cost (1990 

dollars) of $1 million. Annual O&M has been approximately $175,000 to $250,000 depending 

on the species and number of organisms raised and stocked in Maryland waters. 

Habitat Protection Program Participation. The importance of wetlands, in-stream habitat, and 

riparian areas as aquatic habitat for fish and invertebrates and as habitat for wildlife, is reviewed 

in EPRI (2003a). Wetland restoration or habitat restoration in general is becoming increasingly 

popular across the U.S., and there is a growing case history with use of habitat restoration as a 

316(b) mitigation approach (EPRI 2003a). In California, over 90% of its historic wetlands and 

95% of historic streamside trees, shrubs, and ground vegetation has been lost from urbanization, 

agricultural conversion, logging, and flood control (USFWS 2001). Habitat restoration, 

therefore, should be a major interest to federal and state resource agencies and non-governmental 

organizations (NGOs) in California. The following identifies federal, state, and private 

restoration programs that provide information which LADWP may find of value for establishing 

their own restoration program or offer opportunities to LADWP to collaborate on potential 

restoration projects as compensation for impingement mortality and entrainment losses at 

LADWP power plants in southern California. Example programs include: 

• Southern California Edison’s (SCE) San Onofre Nuclear Generating Station 

(SONGS) Mitigation (see 

http://www.sce.com/sc3/006_about_sce/006b_generation/006b1_songs/006b1c_env_prot/006b1c3_songs_miti/default.

htm). The SONGS Marine Mitigation Program is a multifaceted environmental 

enhancement program intended to mitigate unavoidable impacts to the marine 

environment resulting from operation of the SONGS Units 2 & 3 cooling water systems. 

The program includes: 

1) Restoring 150 acres of degraded wetlands at San Dieguito Lagoon to mitigate impacts 

to marine fish populations caused by estimated mortality to fish eggs and larvae; 

2) Improving the in-plant fish protection systems to increase survival of adult fish that 

enter the cooling water systems; 

3) Constructing an artificial kelp reef to mitigate impacts to the San Onofre Kelp 

Bed; 

4) Co-funding a marine fish hatchery program intended as supplementary mitigation 

for kelp impacts; and 

5) Funding for Coastal Commission staff oversight and monitoring of these 

mitigation projects. 
50

SCE is managing the overall mitigation program. Through its Conservation Financing 

Corporation (CFC) subsidiary, the two largest elements of the mitigation program — the 

wetlands restoration project at San Dieguito Lagoon and the artificial reef at San 

Clemente — are being addressed by an equity alliance with an environmental 

management services consulting firm. CFC finances and oversees implementation of 

these two mitigation projects. 

SCE is the plant operator and majority owner of SONGS. SONGS is jointly owned by 

SCE, San Diego Gas and Electric, and the cities of Anaheim and Riverside, which are 

funding the mitigation work. 

The owners of SONGS want to keep interested parties informed about this program, 

which will significantly enhance the region's marine resources. Through meetings, 

discussions, newsletters, a Web site, and the public hearing process, SCE expects to 

inform and involve the largest possible number of interested parties in the development 

and implementation of the mitigation/enhancement plans. Detailed technical progress on 

implementing and monitoring the SONGS mitigation effort appears in the Proceedings 

from the Second Annual Public Workshop for the SONGS Mitigation Project (Reed et al. 

2002). 

• Duke Energy’s Morro Bay Modernization Project Habitat Enhancement Program

(see http://www.duke-energy.com/businesses/plants/own/us/western/morrobay/reports/). As part of the 

station modernization, Duke Energy has volunteered to fund a program that would reduce 

sedimentation and the other major factors undermining the Bay's productivity. The 

concerns for Morro Bay and the target of Duke’s proposal are the issues identified by the 

Morro Bay National Estuary Program's (MBNEP) Comprehensive Conservation 

Management Plan (CCMP). Those issues include sedimentation, loss of habitat, and 

nutrient pollution. Duke’s proposal is its preferred alternative to the California Energy 

Commission’s (CEC) request for dry cooling operation. The Regional Water Quality 

Control Board (RWQCB) staff agrees with Duke’s proposal and believes that habitat 

enhancement would yield greater long-term benefits for the Bay. 

Duke Energy's proposal would fund habitat enhancement projects authorized by the 

RWQCB and managed through professional groups like the MBNEP, which have plans 

and programs to reduce sedimentation and other factors undermining the Bay's 

productivity. The special value of habitat enhancement is that it not only addresses 

marine biology but also protects and enhances habitat for birds and other animals and 

sustains important recreational resources for the community. Documents describing the 

program in detail can be downloaded from the Web site listed above. Because of recent 

economic conditions across the U.S., Duke has canceled plans for modernizing the Morro 

Bay Power Station and, as a result, it has not implemented its habitat enhancement 

project. 

• PSEG’s Delaware Bay Estuary Enhancement Program (see 

http://www.pseg.com/companies/nuclear/estuary/overview.html). This is the largest restoration program 

the U.S. implemented as compensation for impingement and entrainment losses at a 

power station. PSEG negotiated this program, established in 1995, with NJDEP as a 
51

mitigative action for fish losses at the Salem Nuclear Generating Station in lieu of 

implementing a closed-cycle cooling system. Principally focused on the restoration of 

approximately 10,000 acres of former salt hay farms to natural estuarine salt marsh in the 

lower Delaware Estuary, the program also includes provision of fish passage in 

combination with some limited fish stocking to support restoration of anadromous 

(American shad and river herring) fish stocks. Details of the program appear in 

Weinstein et al. (2001). In a following section, we demonstrate the method PSEG used to 

scale (i.e., convert fish loss to acres of equivalent wetland habitat) the size of the requisite 

restoration project. The PSEG incurred costs to date for the ongoing restoration project, 

including capital, O&M, and monitoring, exceed $100 million or $9,350/acre (EPRI 

2003a). 

• Santa Monica Bay Restoration Commission (see 

http://www.santamonicabay.org/site/aboutus/layout/index.jsp). In recognition of the need to restore and 

protect the Santa Monica Bay and its resources, the State of California and the U.S. 

Environmental Protection Agency established the Santa Monica Bay Restoration Project 

(SMBRP) as a National Estuary Program in December of 1988. The Project was formed 

to develop a plan that would ensure the long-term health of the 266 square mile Bay and 

its 400 square mile watershed, located in the second most populous region in the United 

States. That plan, known as the Santa Monica Bay Restoration Plan, won state and 

federal approval in 1995. Since then, the SMBRP's primary mission has been to facilitate 

and oversee the implementation of the Plan. 

On January 1, 2003, the Santa Monica Bay Restoration Project formally became an 

independent state organization and is now known as the Santa Monica Bay Restoration 

Commission (SMBRC). The Santa Monica Bay Restoration Commission continues the 

mission of the Bay Restoration Project and the collaborative approach of the National 

Estuary Program but with a greater ability to accelerate the pace and effectiveness of Bay 

restoration efforts. Restoration activities are based on a comprehensive plan of action for 

Bay protection and management, known as the Bay Restoration Plan, which was 

approved by Governor Pete Wilson in December of 1994 and by USEPA Administrator 

Carol Browner in 1995. The Plan identifies almost 250 actions, including 74 priority 

actions, that address critical problems such as storm water and urban runoff pollution, 

habitat loss and degradation, and public health risks associated with seafood consumption 

and swimming near storm drain outlets. The Plan outlines specific programs to address 

the environmental problems facing the Bay and identifies implementers, timelines, and 

funding needs. 

Implementing the Plan is the focus of current efforts. Securing and leveraging funding to 

put solutions into action, building public-private partnerships, promoting cutting-edge 

research and technology, facilitating a stakeholder-driven consensus process, and raising 

public awareness in order to restore and preserve the Bay's many beneficial uses are key 

objectives of the SMBRC. 

• National Oceanic and Atmospheric Administration (NOAA) Community-based 

Restoration Program (CRP) (see
52

http://www.nmfs.noaa.gov/habitat/restoration/projects_programs/crp/index.html). This program applies a 

grass-roots approach to restoration by actively engaging communities in on-the-ground 

restoration of fishery habitats around the nation. The CRP emphasizes partnerships and 

collaborative strategies built around restoring NOAA trust resources and improving the 

environmental quality of local communities. The program is: (1) providing seed money 

and technical expertise to help communities restore degraded fishery habitats; (2) 

developing partnerships to accomplish sound coastal restoration projects; and (3) 

leveraging resources through national, regional, and local partnerships. This program is 

one of the services of the NOAA Restoration Center. This Center’s mission is to enhance 

living marine resources to benefit the nation’s fisheries by restoring their habitat. 

Working with others, the Center achieves its mission by (1) restoring degraded habitats; 

(2) advancing the science of coastal habitat restoration; (3) transferring restoration 

technology to the private sector, the public, and other government agencies; and (4) 

fostering habitat stewardship and a conservation ethic. Recently, under the communitybased program, NOAA awarded $250,000 to the Gulf of Mexico Foundation for habitat 

restoration in the five states bordering the Gulf of Mexico. EPA, under NOAA’s Gulf of 

Mexico Program (see below) similarly awarded $90,000 to the Foundation. These 

awards launch a major new effort to reclaim essential fish habitats of the Gulf of Mexico 

by implementing field efforts to restore and improve marine and coastal habitats that have 

been degraded or lost. 

• U.S. Fish & Wildlife Service Partnership for Fish & Wildlife (see 

http://partners.fws.gov/index.htm). This program is supported by funds from federal and state 

agencies, private landowners, and non-governmental organizations (e.g., Ducks 

Unlimited, CDFG, the Nature Conservancy). The program is a voluntary partnership 

program with a goal to restore wetlands and other vital habitats on private land with 70% 

of the current funding coming from private sources. The remaining funds, along with 

restoration design and technical assistance, is provided by USFWS. State resource 

agencies, such as CDFG, work with the FWS to help establish priorities and identify 

focus areas. The restoration of degraded wetlands, native grasslands, streams, riparian 

areas, and other habitat to conditions as close as possible to natural is emphasized. The 

Partnership for Fish and Wildlife Program is important for restoration of critical habitats 

in California (USFWS 2001). LADWP could potentially negotiate to give financial 

support to the program and in-kind service could potentially as compensation for 

impingement mortality and entrainment at its power plants in southern California. 

• Coastal America’s Corporate Wetland’s Restoration Partnership (CWRP) (see 

http://www.coastalamerica.gov/text/cwrpoperating.html) is a program designed to foster collaboration 

between the federal government, state agencies, and private corporations. Private 

corporations that participate in this national program will donate funds for either sitespecific wetland or other aquatic habitat restoration projects or provide matching funds to 

a national or regional effort in support of aquatic ecosystem restoration activities. All 

projects that will receive funds from the CWRP will be approved Coastal America 

projects, and federal agencies will assist in their proper execution. The Coastal America 

Partnership will coordinate among all of its Regional Implementation Teams to identify 

the appropriate private foundation or state trust fund that will receive funds from the 
53

CWRP. This organization will not likely accept support in response to regulatory 

requirements. However, the organization is a source of wetland restoration 

information and unique partnerships may be arranged.

Dam removal or fishway construction. An integral component to USFWS and NMFS 

anadromous fish restoration program is the provision of fish passage at existing artificial river 

obstructions. Passage can be obtained via direct dam removal or via the provision of fish 

passage. At the federal level, the key program is the National Fish Passage Program (see

http://fisheries.fws.gov/fwsma/fishpassage/). In 1999, the U.S. Fish and Wildlife Service initiated the 

National Fish Passage Program. The Program uses a voluntary, non-regulatory approach to 

remove and bypass barriers. The Program addresses the problem of fish barriers on a national 

level, working with local communities and partner agencies to restore natural flows and fish 

migration. The Program is administered by National and Regional Coordinators and delivered 

by Fish and Wildlife Management Assistance Offices, with their 300 biologists located across 

the nation. Appropriations for the Program support the Coordinators, in-the-water fish passage 

projects, and the Fish Passage Decision Support System (subsequently described). The 

Program’s goal is “to restore native fish and other aquatic species to self-sustaining levels by 

reconnecting habitat that has been fragmented by barriers, where such re-connection would not 

result in a net negative ecological effect such as providing increased habitat to exotic species.” 

The Fish Passage Decision Support System (see https://ecos.fws.gov/fpdss/index.do) is a database of 

barriers preventing fish movement that is complemented by analytical tools (GIS software) for 

mapping and prioritizing fish passage projects (calculating stream mileage made available by 

providing fish passage at the barrier). Barrier information includes location, type, size, owner, 

passage capabilities, associated fish species, and local habitat information. 

CDFG and NMFS are actively involved in efforts to restore anadromous salmonids in 

California’s coastal rivers. In the area of the LADWP facilities, restoration of the southern 

steelhead is a species of particular concern. While restoration efforts to date have been largely 

based on hatchery supplementation, RWQCB or other state and federal resource agencies may be 

receptive to the development of efforts to restore access to historical spawning habitat via dam 

removal (e.g., see Pejchar and Warner 2001) and or fish laddering at river barriers. As 

mitigation for impingement mortality and entrainment impacts at LADWP’s power plants, 

LADWP could negotiate removal of one or more dams or provide fish passage where dam 

removal is not an option. Alaska Steeppass fish ladders offer an effective and moderate cost 

approach for fishway provision. PSEG of New Jersey has successfully installed such fishways in 

tributaries to the lower Delaware Bay to restore access to historical spawning habitat for 

American shad, alewife, and blueback herring. Dam removal, if LADWP pursued it, would 

focus on abandoned, non-hydropower projects, such as old low-head mill dams or flow control 

structures (river levees). The Rindge Dam on Malibu Creek (see 

http://www.irn.org/revival/decom/alerts/rindgealert.html), for example, is under strong consideration for 

removal. Consensus is building among local NGOs and federal and state resource agencies that 

this aging and silted-in dam should be removed to speed southern steelhead recovery efforts. 

Steelhead once spawned as far as 3 miles upstream. Removal of this structure would reopen the 

habitat to potential spawning by this endangered species. The major impediment to removal is a 

lack of funding. The California State Department of Parks and Recreation is acting as the 
54

clearinghouse for securing the state’s share of the funding. Federal efforts are being led by the 

U.S. Army Corps of Engineers. LADWP could combine fish passage programs with stocking to 

restore specific anadromous species of concern such as the southern steelhead. As we previously 

noted, such an approach was successful for restoring American shad to the Susquehanna River in 

Pennsylvania and Maryland. 

Alternative restoration measures. We have identified the measures discussed above as the most 

likely restoration approaches to appeal to RWQCB and other federal and state resource agencies. 

Other potential approaches include nonpoint source pollutant runoff abatement programs and 

contaminated sediments restoration. While these types of efforts focus on water quality 

improvements, the long-term benefit is improved fish and shellfish habitat. Such efforts would 

have to demonstrate a clear linkage between the two as compensation for impingement mortality 

and entrainment losses at LADWP’s southern California power stations. The California Coastal 

Commission is implementing a statewide Nonpoint Source (NPS) Program (see 

http://www.coastal.ca.gov/nps/npsndx.html). Elements of the plan include management measures for 

reducing runoff pollution from agriculture, silviculture, urban areas, marinas and recreational 

boating, and via hydromodification (includes modification of stream and river channels, dams 

and water impoundments, and streambank/shoreline erosion). CCC, therefore, is a source of 

information for developing a potential nonpoint source runoff abatement program or 

implementing best management practices (BMPs) to meet the goals of the state’s plan in the Los 

Angeles urban and suburban areas. RWQCB may welcome direct support by LADWP toward 

implementing some of the BMPs as compensation for the impingement (and entrainment losses) 

at LADWP power plants. 

5.6 Implementing a Restoration Program for LADWP’s Haynes, Harbor, and 

Scattergood Generating Stations 

Estimating the size and cost of a potential restoration project is a complex process and beyond 

the scope of the current service. SCE’s and Duke Energy’s experience in California, however, 

provide valuable context. The size of a project and its cost are also the result of an iterative 

negotiation/investigation process with the resource agencies. If restoration is of potential 

interest, LADWP should initiate appropriate planning and consultation with the agencies. We 

discuss information that LADWP must ultimately file below. However, there are a number of 

steps that we recommend prior to the development of any specific restoration project plans. 

These steps are as follows:9

1. Initiate preliminary consultation with the federal and state resource agencies to identify 

 

9

 There is no formal guidance from EPA or any other organization on planning restoration projects relative to 

meeting the requirements of the final Phase II §316(b) Rule. Procedures essentially are developed on a site-specific 

basis. LADWP can use procedures at other power plants as guidance. EPA is not expected to issue guidance of any 

type relative to the developing 316(b) rules until 2006 or even later. In late 2004, EPRI will deliver to its members a 

report that provides more definitive guidelines on planning restoration projects. 
55

“species of concern,” habitat requirements, and potential restoration measures.10

2. Impingement mortality and entrainment monitoring data at LADWP’s Haynes, Harbor ,and 

Scattergood Generating Stations are the requisite data to support the baseline 

characterization, evaluation of technology options, cost-benefit calculations (i.e., benefit 

monetization), and initial input to calculating restoration goals (i.e., to support both 

“comparable performance” and estimate the requisite size of the restoration project as 

subsequently discussed). 

3. LADWP must convert data from impingement mortality and entrainment monitoring to 

annual “equivalent adult” (for recreational gamefish) and “production foregone” (for forage 

fish) losses. EPRI will publish a report in late 2003 describing in detail the procedures for 

both calculations. Existing literature that reviews each of these concepts appears in EPRI 

(2003a), Goodyear (1978), Rago (1984), and Jensen et al. (1988). 

4. Calculate requisite units of restoration that mitigate for CWIS impingement mortality and 

entrainment losses (or appropriately scale restoration such that benefits are comparable11 to 

what a facility could attain with technology or operational restriction options). The science 

of restoration scaling is in its infancy, and EPA provides no guidelines, nor can we expect it 

to in the near future. Scaling that has been done has been negotiated with permit directors on 

a site-specific basis (e.g., PSEG for Delaware Estuary, DENA for Morro Bay Station). The 

new EPRI report on restoration science (EPRI 2003a) includes a chapter that summarizes the 

state of science (i.e., scaling methods, data needs, uncertainties) on appropriately scaling 

restoration to compensate for impingement mortality and entrainment losses at power 

stations (an example scaling approach is subsequently discussed). Scaling for hatchery 

supplementation is more direct: Fish are raised and stocked at a level slightly higher than 

that lost (per equivalent adult and production foregone loss calculations) due to impingement 

mortality and entrainment. The slightly higher supplementation is a safety factor that 

addresses uncertainty in survival following stocking. 

5. Present plan, including all requisite information noted in the following section, to 

SDRWQCB. Continue consultation and plan development until approved and formally 

included as a permit condition. 

6. Implement restoration measure, maintain, and monitor performance per permit conditions. 

 

10 Scientists at the Marine Science Institute of the University of California, Santa Barbara (e.g., Dan Reed, Steve 

Schroeter) have extensive experience working on the SONGS Mitigation Project. Independent, out-of-state experts 

include Drs. Kenneth Rose and James Cowan, Jr., at the Louisiana State University Coastal Fisheries Research 

Center, both of whom have extensive experience in the development and implementation of restoration projects as 

mitigation for Clean Water Act §316(b). Each of these individuals is a valuable source of information to help 

LADWP in restoration planning should LADWP decide to pursue such activities. 

11 Under conditions of lack of guidance from EPA on determining “comparability” of restoration benefits to other 

technology options, final determination will reside with the permit director — relative to Haynes, Harbor, and 

Scattergood, LARWQCB. Lack of guidance will allow considerable flexibility in reaching these determinations. 

However, given California’s (Coastal Conservation Commission and RWQCB’s extensive experience in the design 

and implementation of DENA’s and SCE’s programs, LADWP should expect that it will likely require detailed

comparability assessments. 
56

Historically, organizations have used two general approaches to implement restoration projects. 

These approaches are: 

• Self-directed/managed projects. The power company identifies the restoration project, scales 

it accordingly, secures the property or access, designs the effort, manages implementation, 

and conducts monitoring to ensure design performance, then makes necessary adaptive 

management adjustments. This is the approach that PSEG has used for its Delaware Estuary 

Restoration Program for the Salem Nuclear Station. Southern California Edison (SCE) is, 

through its Conservation Financing Corporation, similarly self-managing its restoration 

efforts (artificial reef, wetland restoration, and fish hatchery) for 316(a & b) impacts by the 

San Onofre Nuclear Generating Station (SONGS). Mirant Inc. (PEPCO) self-managed its 

fish hatchery as compensation for entrainment impacts at its Chalk Point Station. 

• Contribution to a restoration fund. The power company works with another entity to identify 

a project, scale it accordingly, and determine the funds necessary to implement, manage, and 

monitor. Funds are then provided to the third party, which may leverage such funds to 

further expand the restoration efforts. This is the approach that Duke Energy North America 

(DENA) has used for its Moss Landing Station and Morro Bay Station in California. In the 

former, DENA made a one-time contribution to the Elkhorn Slough Foundation of $7 million 

for its management of estuary restoration efforts. For the latter, DENA attempted to 

negotiate a one-time contribution (~$14 to 21 million) to the Morro Bay Estuary Program to 

manage restoration projects in Morro Bay. Because plans to modernize the Morro Bay 

Power Plant have been put on hold, further negotiation with CEC and RWQCB have also 

been suspended. 

EPA provides no guidance or recommendation relative to the preferred approach. Each approach 

has its limitations and advantages that are highly influenced by local non-governmental 

organizations, federal agencies, and state resource agencies, including the permit issuing 

organization. 

We present for consideration two methods for scaling restoration projects that are similar in 

fundamental science: (1) PSEG’s approach for its Estuary Enhancement Program and (2) Duke 

Energy North America’s approach for its Morro Bay Power Station in California. 

PSEG Scaling for the Salem Generating Station Fish & Shellfish Losses

The PSEG Estuary Enhancement Program is founded on the premise that primary production of 

salt marshes is linked to the production of marine transient taxa. PSEG needed two calculations 

to estimate the area of marsh needed to produce fish to offset losses at the power plant: 

1. Annual fish biomass produced from Delaware Bay marsh primary production 

2. Annual fish biomass lost in once-through cooling at the plant. 

PSEG then used the following formula to derive an estimate of wetland acreage for mitigation: 
57

Fish biomass production per acre of wetland

Fish biomasslost due to power plant operation Acres of wetlands=

PSEG based estimates of fish loss due to impingement and entrainment on sampling results as 

converted to annual losses using the equivalent adult and production foregone impact assessment 

methods as previously noted. For comparability with wetland productivity units in dry weight, 

fish biomass lost (BL) were converted to dry weights by multiplying the BL by an appropriate 

wet weight to dry weight (DW) conversion factor. PSEG based its estimate of the fish biomass 

produced per wetland acre on an aggregated food chain model (AFCM) approach. The principle 

underlying this model is that biomass produced by wetlands vegetation is transferred through the 

food chain to higher level consumers including all five species at issue at Salem (bay anchovy 

weakfish, spot, white perch, and possum shrimp). The model simplified complex food web 

interactions by aggregating species across trophic levels. In the AFCM, this biomass was 

calculated by multiplying wetland-based primary productivity ("PP") by appropriate conversion 

efficiency ("CE") factors between succeeding trophic levels (CE0, CE1, and CE2). This biomass 

is then apportioned among individual second-level consumer species (including those species at 

issue) by multiplying the result of the AFCM by the individual species' apportionment factor (A). 

These calculations are summarized in the equation below: 

Fish production per acre of wetland = [PP × CE0 × CE1 × CE2] × A

where 

PP = Primary productivity per acre of wetland (lb. dry weight/acre/year) 

CE0 = Efficiency of biomass conversion from primary productivity to the detrital 

complex 

CE1 = Efficiency of biomass conversion from the detrital complex to first level 

consumers 

CE2 = Efficiency of biomass conversion from first level consumers to second level 

consumers 

A = Apportionment of the wetland-based secondary consumer productivity to the 

individual species at issue. 

The original equation: 

Fish biomass production per acre of wetland

Fish biomasslost due to power plant operation Acres of wetlands=

is now expressed as: 
58

[PP x CE x CE x CE ] x A

BL x DW Acres of wetlands= 0 1 2

PSEG derived the values for the parameters above from the literature or from monitoring surveys 

in Delaware Bay and environs. Details appear in Weinstein et al. (2001) and in the PSEG permit 

filings in NJDEP permit office. Using these formulas and input parameter values, PSEG 

estimated that approximately 2,500 acres of restored wetlands would mitigate for losses of key 

species at the Salem Station. However, in light of uncertainties and variability surrounding the 

assumptions and estimates used to construct the model, PSEG used a ”safety factor” of about 

four to achieve consensus among stakeholders, including NJDEP. Thus the final project 

involves restoring approximately 10,000 acres of wetlands along the New Jersey shore of the 

lower Delaware Estuary12. 

DENA Method for Morro Bay Station, California

Duke Energy North America (DENA) developed the following Habitat Equivalency Analysis 

(HEA) to determine requisite wetland restoration to compensate for impingement and 

entrainment losses at the Morro Bay Power Plant in California (Duke Energy Morro Bay LLC 

2002). HEA is an analytical method that National Oceanic and Atmospheric Administration 

(NOAA) initially developed to quantify natural resource and service reductions associated with 

oil spills and services gains associated with restoration actions taken in response to those spills. 

More detailed information on HEA appear in NOAA (1997), Strange et al. (2002), and Duke 

Energy Morro Bay LLC (2002 — can be downloaded at http://www.dukeenergy.com/businesses/plants/own/us/western/morrobay/reports/). We provide this example13 to illustrate a 

possible approach and the requisite data to support appropriate scaling. 

Step 1: Convert estimated entrainment numbers of fish and crabs to biomass (debit) 

Summed entrainment losses of fish and crabs based on entrainment sampling to kg/year: 

4,670 kg of fish/year and 2,983 kg of crabs/year 

Step 2: Calculate discounted amount of entrained biomass over life of power plant (debit) 

Projected total biomass lost over 50 years at a discount rate of 3%: 120,167 kg of fish and 

76,759 kg of crab 

 

12 PSEG’s Salem Station is one of the largest power stations in the U.S. and one of the largest daily withdrawals of 

estuarine water. The plant is also located in an estuarine zone, where entrainment of early life stages of fish is the 

greatest within Delaware Bay. As such, habitat equivalency to compensate for entrainment losses are extremely 

large (~10,000 acres), particularly when compared to habitat equivalency calculated for the subsequent Morro Bay 

Power Plant example (~60 acres). 

13 This example is superficial in presentation. It should also be noted that not all parties (i.e., CEC and RWQCB) to 

Duke Energy’s Habitat Enhancement Plant concur with the application of HEA in relation to its traditional use by 

NOAA. The example is simply to illustrate the fundamental steps in scaling of fish losses to units of habitat 

restoration. 
59

Step 3: Estimate (from literature) habitat (e.g., eelgrass or salt marsh) productivity (credit) 

Marsh productivity in California based on the scientific literature ~ 20,235 kg/acre/year 

Step 4: Convert habitat productivity to fish and crab biomass (credit) 

Based on trophic transfer efficiencies fish and crab production was estimated at 0.4% and 

4.0%/acrea: 80.96 kg of fish and 809 kg of crab 

Step 5: Calculate discounted amount of fish and crab biomass (credit) 

Projected total biomass gained over 100 years (lifetime of the restoration project) at a 

discount rate of 3%: 2,231 kg/acre of fish and 22,319 kg/acre of crab 

Step 6: Estimate habitat acres sufficient to equate the service “credit” to “debit” 

120,167 kg fish loss/2,232 kg/acre = 53.8 acres of restored marsh to offset fish losses 

at the power plant

76,759 kg crab loss/22,319 kg/acre = 3.4 acres of restored marsh to offset crab losses 

at the power plant 

TOTAL ACRES OF REQUIRED RESTORATION = 57.2

LADWP would need to submit considerable documentation, as we subsequently discuss, to 

support such an accounting. Duke’s HEP (2002) is illustrative of the requisite breath of 

information that LADWP would need to provide and discuss. 

5.7 Information That LADWP Must Submit 

Table 5-1 lists the specific requirements of the required Restoration Plan that LADWP must file 

if a facility proposes to use restoration measures, in whole or in part, to meet the applicable 

requirements in §125.94 (compliance alternatives and performance standards) of the final Phase 

II Rule. 

5.8 Summary 

Proposal and implementation of a restoration measure offers LADWP an alternative approach to 

compensate for impingement mortality and entrainment impacts at its Haynes, Harbor, and 

Scattergood facilities. In fact, restoration may be the most attractive approach toward meeting 

site-specific BTA standards under the Cost-Benefit variance should LADWP obtain a sitespecific determination.14 Furthermore, LADWP may wish to consider one restoration effort that 

addresses the compliance requirements of all its power plants in southern California. Under the 

waterbody/watershed approach required by EPA for the spatial context of a restoration effort, a 

 

14 LADWP must volunteer restoration, it cannot be requested by SDRWQCB. Implementation of a successful 

restoration project may also provide mutual benefits to both LADWP and the State of California. 
60

facility may propose and implement such a single or unified effort. LADWP must perform 

considerable planning and consultation with RWQCB and fish and wildlife management 

agencies, as we discuss herein, to accomplish this. 

This review and discussion of potential restoration measures does not include a review of 

potential restoration costs for future budgeting. Restoration costs are dependent upon units of 

restoration required (that compensate for fish losses), the type of restoration project, and land 

values in the area where a facility may implement a restoration project. The experiences of SCE 

in compensating for fish losses at SONGS offer some insight into potential costs. LADWP 

should, however, view the costs incurred with the understanding that the SONGS program 

mitigates for total impacts associated with operation of its cooling system (intake and discharge 

effects) and impacts associated with construction of the intake and discharge system pipes. As 

noted herein, SCE provided $4.7 million in funding for a white sea bass hatchery. When 

operating at design capacity, the hatchery is expected to produce 300,000 juvenile white sea bass 

per year. This white sea bass production is expected to exceed compensation for the total 

SONGS fish losses estimated by the CCC Marine Review Committee (expert panel). In addition 

to these costs, SCE will be restoring 143 acres of wetlands in the San Dieguito River Valley at a 

cost estimated at $86 million. Furthermore, in 2005, SCE will build out its experimental kelp 

reef to a full 150-acre required size at an estimated cost, including post-construction monitoring, 

of $40 million. Monitoring of the experimental kelp reef and wetlands currently costs SCE about 

$1.2 million annually. 
61

Table 5-1 EPA Requirements for the Content of Restoration Plans 

Final Phase II 

Rule Section 

Descriptive Requirement Comment 

§125.95 (b)(5) Restoration Plan. If you propose to use restoration 

measures, in whole or in part, to meet the applicable 

requirements in §125.94 [compliance alternatives 

and performance standards], you must submit the 

following information with your application for 

review and approval by the permitting authority. 

You must address species of concern identified in 

consultation with Federal, State, and Tribal fish and 

wildlife management agencies with the responsibility 

of fisheries and wildlife potentially affected by your 

cooling water intake structure(s). 

This plan would be filed as part of 

your Comprehensive 

Demonstration Study (CDS). The 

CDS will be filed 6 months prior to 

expiration of the current facility 

permit. Your intent to examine 

restoration measures as a possible 

compliance approach would be 

noted in your Proposal for 

Information Collection (PIC) 

which will be due within the next 12 

to 18 months. 

§125.95 (b)(5)(i) A demonstration to the permitting authority that you 

have evaluated the use of design and construction 

technologies and/or operational measures for your 

facility and an explanation of how you determined 

that restoration would be more feasible, costeffective, or environmentally desirable; 

The information contained in this 

report is the start of that process. 

Your PIC will list the technologies 

and operational measures that you 

plan on examining in a more 

detailed (BTA) process. This 

demonstration would be contained 

in your CDS. 

§125.95 (b)(5)(ii) A narrative description of the design and operation 

of all restoration measures (existing and proposed) 

that you have in place or will use to produce fish and 

shellfish; 

§125.95 (b)(5)(iii) Quantification of the ecological benefits of the 

proposed restoration measures. You must use 

information from the required Impingement 

Mortality and/or Entrainment Characterization 

Study, and any other available and appropriate 

information, to estimate the reduction in fish and 

shellfish impingement mortality and/or entrainment 

that would be necessary for your facility to comply 

with §125.94(c)(2) [production of ecological benefits 

equivalent to meeting impingement and entrainment 

reduction requirements]. You must then calculate 

the production of fish and shellfish that will be 

achieved with the restoration measures you will or 

have already installed. You must include a 

discussion of the nature and magnitude of 

uncertainty associated with the performance of these 

restoration measures. You must also include a 

discussion of the time frame within which these 

ecological benefits are expected to accrue; 

“Scaling” addresses the 

quantification requirement. I&E 

losses, as documented in your 

Impingement Mortality and 

Entrainment Characterization Study, 

is the starting point in the process. 

Scaling is accomplished based on a 

theoretical analysis using 

productivity values in the technical 

literature. Example scaling for 

wetlands is included herein. 

Some recent key papers on 

restoration scaling include Peterson 

et al. (2003a), Peterson et al. 

(2003b), McCay and Rowe (2003), 

Powers et al. (2003), Kneib (2003), 

and Peterson and Lipcius (2003). 

§125.95 (b)(5)(iv) Design calculations, drawings, and estimates to 

document that your proposed restoration measures in 

combination with design and construction 

technologies and/or operational measures, or alone, 

will meet the requirements of §125.94(c)(2) 

[production of ecological benefits equivalent to 

There is some level of redundancy 

here with the previous requirement 

with regards to scaling. “Out-ofkind” restoration gets at the 

previously footnoted issue that the 

resource agencies are not likely to 
62

meeting impingement and entrainment reduction 

requirements]. If the restoration measures address 

the same fish and shellfish species identified in the 

Impingement Mortality and/or Entrainment 

Characterization Study (in-kind restoration], you 

must demonstrate that the restoration measures will 

produce a level of these fish and shellfish 

substantially similar to that which would result from 

meeting applicable performance standards in 

§125.94(b) [impingement mortality and entrainment 

reduction standards], or that they will satisfy sitespecific requirements established pursuant to 

§125.94(a)(5) [cost-cost or cost-benefit tests]. If the 

restoration measures address fish and shellfish 

species different from those identified in the 

Impingement Mortality and/or Entrainment 

Characterization Study (out-of-kind restoration), you 

must demonstrate that the restoration measures 

produce ecological benefits substantially similar to 

or greater than those that would be realized through 

in-kind restoration. Such a demonstration should be 

based on a watershed approach to restoration 

planning and consider applicable multi-agency 

watershed restoration plans, site-specific peerreviewed ecological studies, and/or consultation with 

appropriate Federal, State, and Tribal fish and 

wildlife management agencies. 

look for replacement of lost forage 

fish (e.g., gizzard shad, threadfin 

shad, bay anchovy, or other ‘rough’ 

species). Instead, they would 

(assuming they support the 

restoration concept) prefer targeting 

the restoration at a gamefish or 

commercial fish or some other 

species of special concern. This 

‘demonstration’ again is a 

theoretical analysis based on data in 

the technical literature. 

The watershed approach provides 

great spatial flexibility toward 

implementing a project. For 

example, a restoration effort could 

be directed at the headwaters of the 

watershed in which the facility is 

located or within tributaries. 

Projects can also be implemented 

downstream of the facility. 
63

§125.95 (b)(5)(v) A plan using an adaptive management method for 

implementing, maintaining, and demonstrating the 

efficacy of the restoration measures you have 

selected and for determining the extent to which the 

restoration measures you have selected and for 

determining the extent to which the restoration 

measures, or the restoration measures in combination 

with design and construction technologies and 

operational measures, have met the applicable 

performance requirements of §125.94(c)(2) 

[production of ecological benefits equivalent to 

meeting impingement and entrainment reduction 

requirements]. The plan must include: 

A. A monitoring plan that includes a list of the 

restoration parameters that will be monitored, 

the frequency at which you will monitor them, 

and success criteria for each parameter; 

B. A list of activities you will undertake to ensure 

the efficacy of the restoration measures, a 

description of the linkages between these 

activities and the items in paragraph (b)(5)(v)(A) 

of this section [above note on the required 

monitoring plan], and an implementation 

schedule; and 

C. A process for revising the Restoration Plan as 

new information, including monitoring data, 

becomes available, if the applicable 

requirements under §125.94(c)(2) [production of 

ecological benefits equivalent to meeting 

impingement and entrainment reduction 

requirements] are not being met. 

EPA defines adaptive management 

as a type of project management 

method where a facility chooses an 

approach to meeting the project 

goal, monitors the effectiveness of 

that approach, and then based on 

monitoring and any other relevant 

information, makes any adjustments 

necessary to ensure continued 

progress toward the project’s goal. 

This cycle of activity is repeated as 

necessary to reach the project’s 

goal. 

§125.95 (b)(5)(vi) A summary of past or ongoing consultation with 

appropriate Federal, State, and Tribal fish and 

wildlife management agencies on your use of 

restoration measures including a copy of any written 

comments received as a result of such consultations; 

Consultation should begin prior to 

submitting the PIC (i.e., within the 

next 6 to 18 months). Consultation 

is necessary to obtain the resource 

agencies’ and permitting authority’s 

concurrence on the restoration 

concept and method, and in shaping 

reasonable expectations from the 

restoration effort. 

§125.95 (b)(5)(vii) If requested by the permitting authority, a peer 

review of the items you submit for the Restoration 

Plan. You must choose the peer reviewers in 

consultation with the permitting authority who may 

consult with EPA and Federal, State, and Tribal fish 

and wildlife management agencies with 

responsibility for fish and wildlife potentially 

affected by your cooling water intake structure(s). 

Peer reviewers must have appropriate qualifications 

(e.g., in the fields of geology, engineering, and/or 

biology, etc.) depending upon the materials to be 

reviewed; and 

University professors, such as those 

recommended herein, generally can 

offer unbiased peer review support, 

if it is requested. 

§125.95 (b)(5)(viii) A description of the information to be included in a 

bi-annual status reports to the permitting authority. 
64

Section 6 

ESTIMATED COSTS 

The costs associated with meeting the Rule will likely determine the compliance strategy that is 

most desirable at Harbor. Preliminary installation and O&M costs associated with each of the 

alternatives identified in Section 3 and developed in Section 4 are presented below. The 

following costs are included: 

• the costs that EPA assigned to a facility similar to your facility for the purpose of 

estimating the national costs for implementing the Rule; 

• order of magnitude costs for selected technologies based from historical data and 

Alden’s best professional judgment; 

• costs associated with permitting and monitoring; and 

• the potential for satisfying the Cost-Cost and Cost-Benefit tests to obtain a sitespecific BTA determination (Compliance Alternative 5) 

6.1 EPA Costs 

EPA costs are based on the Technology Cost Modules published in the Technical Development 

Document (TDD) (EPA 2004b). EPA developed costs for all Phase II facilities to estimate the 

total costs that the power industry will face as a result of implementing the Rule on a national 

level. To determine the costs for a facility, EPA determined which national performance 

standards apply and which technology would be best suited to each facility based upon either the 

long or short EPA questionnaires, and publicly available aerial photographs. EPA then estimated 

the costs for the selected technology using the appropriate Cost Module for each Phase II facility. 

There are 14 Cost Modules, one for each of EPA’s selected technologies (Table 6-1). The 

costing methodology of the Cost Modules is based on historical data from sites that already 

incorporate EPA approved technologies, consultation with manufactures of those technologies, 

and detailed design studies. Each of these modules contains Capital and O&M costs, as well as 

costs associated with construction shutdowns. 

To assist facilities in understanding the costs EPA used in determining the national cost, EPA 

supplied two appendices with the Rule. Information for Harbor from both these appendices is 

summarized in Table 6-2. 

To annualize the Capital and O&M costs, EPA made several assumptions 

• All costs are based on 2002 dollars 

• a discount rate of 7%, 

• an amortization period of 10 years for the capital costs 

• 30 year amortization period for the pilot study and downtime costs 
65

To determine the cost that EPA estimates Harbor will incur in order to meet the performance 

standards via a technology alternative, EPA provided a five step methodology. A summary of 

the methodology, and how to apply it to Harbor, is provided below. 

Step 1: Determine which technology EPA selected as the most appropriate compliance 

technology for Harbor 

Step 2: Using the costs in Table 6-2, calculate the annualized capital and net operation 

and maintenance costs for the facility using the following formula: 

yf = yepa + m∗(xf - xepa), 

where 

yf = annualized capital and net O&M costs using actual facility design 

intake flow, 

xf = actual facility design intake flow (gpm), 

xepa = EPA assumed facility design intake flow (gpm), 

yepa = Annualized capital and net O&M costs using EPA design intake 

flow 

and 

m = design flow adjustment slope.

Step 3: Determine the annualized net revenue loss associated with construction 

downtime to install the technology and the annualized pilot study costs that EPA 

selected for Harbor. The sum of these two costs is shown on the second to last 

row of Table 6-2. 

Step 4: Add together the costs from Step 2 and 3 to get the preliminary costs considered 

by EPA for Harbor. 

Step 5: Determine if the performance standard assigned by EPA for Harbor as reported 

in EPA’s Appendix A is in fact the performance standard that applies to the 

facility. If EPA selected IM&E for a facility, but only the impingement mortality 

reduction standard applies, then the cost in Step 4 should be divided by a factor of 

2.148 to get the final costs. If EPA selected only impingement mortality 

reduction standard for a facility, but both IM&E standards apply, then multiply 

the cost in Step 4 by a factor of 2.148 to get the final costs. 

EPA estimated that Harbor would only have to meet the IM reduction standard and applied Cost 

Module 1 (Addition of fish handling and return system to an existing traveling screen system). 
66

As Harbor withdraws water from the ILAHC and has a capacity factor of greater than 15% the 

facility will be required to meet the IM&E standards. To compensate for this error the Team 

applied the five step adjustment described above. As a result the cost that LADWP would use if 

it were to apply for a site-specific BTA determination via the cost test is $130,007. This cost 

would not be affected if LADWP were to meet the IM standard due to the low through-screen 

velocity, as technologies used to meet the E standard would also meet the IM standard. 

6.2 Estimated Costs for Technology Intake Alternatives 

Appraisal level project costs were developed for the four alternatives discussed in Section 4. The 

costs were estimated using Alden’s cost database of alternatives for over 35 plants and a 

comparison of the conceptual designs for each of the alternatives to adjust costs for identifiable 

differences in project sizes and operations. Due to the generalized nature of these costs appraisal 

level estimates are intended to identify the relative cost differences between alternatives and the 

cost of compliance in relation to the EPA selected technology for a facility. More detailed cost 

estimates based on detailed quantity takeoffs would be required if LADWP plans to apply one of 

these alternative technologies at Harbor. 

Costs in Alden’s historical database typically reflect the following assumptions: 

• Present day prices and fully contracted labor rates; 

• Forty-hour workweek with single shift operation for construction activities that do not 

impact facility operations and fifty-hour workweek with double shift operation for 

construction activities that impact facility operations; 

• Direct costs for material and labor required for construction of all project features; 

• Distributable costs for site non-manual supervision, temporary facilities, equipment 

rental, and support services incurred during construction. These costs are estimated to be 

85-100% 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 are estimated to be 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 is estimated to be 10% of the direct, distributable, and indirect costs of 

each alternative; and 

• 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 is estimated to be 15% of the direct, distributable, indirect, and allowance for 

indeterminate costs of each concept. 

The costs do not include the following items that will affect estimates of the total capital costs: 

• Costs to perform additional pilot studies including laboratory or field studies that may be 

required; 
67

• Costs to dispose of any hazardous or non-hazardous materials that may be encountered 

during excavation and dredging activities; 

• Costs for administration of project contracts and for engineering and construction 

management incurred by LADWP. 

• Escalation (increases in wages, materials, and other costs as a result of various economic 

factors) 

• Permitting costs 

For a closed-cycle cooling system alternative, EPRI’s estimated costs were used (EPRI 2002a). 

This study reflected retrofit cost data from 50 nuclear and fossil plants on fresh, brackish, and 

saline water sources. Facility sizes were 100 to 2,600 MW with cooling tower retrofit costs 

ranging between $11 million and $860 million. Costs are $125/gpm for “easy” projects, 

$200/gpm for “average” projects, and $250-$300/gpm for “difficult” projects (EPRI 2002a). 

Power to operate cooling towers is typically 1.0-1.5% of the facility capacity and O&M costs are 

typically 1-2% of the tower capital costs (EPRI 2002a). 

To allow Alden’s cost estimates to be directly comparable to EPA’s cost for a like facility, Alden 

had to adjust its costs to be consistent with the methodology used by EPA in developing the 

national costs. Their adjustments are listed below: 

• All costs are given in 2002 dollars 

• At nuclear facilities, both the O&M and Capital costs for a given technology were 

multiplied by a cost factor to account for additional burdens as a result of added security 

and safety requirements. 

• A cost factor ranging from 1.1 to 1.2 (based upon well depth) was added to the cost of 

Ristroph screens for the installation of dual flow screens. 

• The cost for wedge wire screens was adjusted by a factor of 1.1 for facilities located on 

salt water or in a state with zebra mussels. 

Costs for intake technologies and operational measures based on Alden’s database are shown in 

Table 6-3. In addition to initial capital costs and annual O&M costs, this table includes costs 

(lost generation and potential lost revenue) associated with construction shutdowns and energy 

penalties. Where applicable, costs were included for losses in generating capacity as a result of 

the compliance option. For technologies that do not require the use of the existing traveling 

screens, the annualized O&M costs are the O&M costs for a given alternative minus baseline 

O&M costs. Included in Table 6-2 is EPA's estimated baseline O&M cost. The last column in 

this table is the total annualized cost for each alternative. To allow this cost to be compared to 

the cost of the EPA selected alternative, the same discount rate, amortization period, and 

durations described in Section 6.1 were used. As shown in Table 6-3, the annualized Alden costs 

for intake retrofit alternatives range from $0 for the existing operations to $486,000 for fine mesh 

Ristroph screens. Cooling tower retrofit costs for Harbor would be about $3,206,000 annually. 

6.3 Permitting and Monitoring Costs 

The costs associated with completing the permit application and the associated monitoring can 

be a substantial part of the total cost of compliance. These costs are highly dependant on which 
68

performance standard(s) apply along with the costs for the selected compliance alternative. 

Since Harbor is required to meet both the IM&E reduction standards, it would have to perform 

both IM&E monitoring. To account for some of the site-specific variability in these costs the 

Team provides cost ranges, the actual cost of permitting and monitoring would depend upon 

which compliance alternative LADWP chooses. The Team’s estimated cost ranges for 

permitting and monitoring are compared to the maximum cost EPA expects in Table 6-4. In the 

TDD, EPA based its costing methodology on the type of waterbody a facility withdraws from, 

not which standard applies. EPA also only provided costs for studies it expects most facilities 

will incur, and only the maximum burden cost for these studies, as a result some of the studies 

that the Team costed do not have comparable EPA costs. Total permitting costs for Harbor 

could be expected to range from $170,000 for one year of sampling and no pilot study costs up to 

$700,000 for two years of sampling and a one-year pilot study with a Ristroph screen. These 

costs should only be used for preliminary budgeting; LADWP would have to do site-specific 

costing to determine the actual cost of the permitting and monitoring requirements. 

6.4 Cost-Cost Test 

A site-specific BTA determination (Compliance Option 5) could be pursued by LADWP if 

Harbor satisfies the requirements of the Cost-Cost test. This test is a comparison of the 

annualized Capital and O&M costs for the EPA selected technology to the site-specific costs for 

a technology, operational measure, or restoration alternative that has potential to meet the 

applicable performance standards. If the site-specific costs are “significantly greater than” those 

determined by EPA, then a site-specific determination of BTA may be a viable compliance 

alternative at Harbor. 

To determine the site-specific costs at a facility, a Comprehensive Cost Evaluation Study must 

be completed. This study includes a detailed engineering cost estimate of the technologies, 

operational measures, and/or restoration measures that have been proposed to meet the 

applicable performance standards the facility. Once these costs have been calculated, they can 

be compared to the cost EPA selected to determine if the site-specific costs are “significantly 

greater than” EPA’s costs. It is important to note that EPA has not defined “significantly greater 

than,” so it is not possible at this time to determine conclusively if a facility will satisfy the 

requirements of the Cost-Cost test. The Comprehensive Cost Evaluation Study should also 

include costs for other options included in the Site-Specific Technology Plan that are not 

“significantly greater than” the costs EPA considered when formulating the Rule and that have 

potential for meeting a lesser standard as prescribed by the Director.

A preliminary evaluation of the applicability of the Cost-Cost test based on the Team’s rough 

costs can be made by comparing the annualized costs in the last column of Table 6-3 to the sum 

of the costs presented in the last row of Table 6-2. 
69

6.5 Cost-Benefit Test 

The Cost-Benefit test is the second method of obtaining a site-specific BTA determination 

(Compliance Alternative 5). This alternative is a comparison of the monetized benefits gained 

from complying with the Rule at a given facility to the site-specific costs for a technology, 

operational, or restoration alternative. If the site-specific costs are “significantly greater than” 

the benefits, then Harbor would be eligible for a site-specific determination of BTA based on the 

Cost-Benefit test. 

To calculate the benefits of compliance with the Rule, a Benefits Valuation Study should be 

included in the CDS. The first step in the study is the completion of the IM&E Study. The 

results of this study are used as the basis for benefits monetization. This IM&E Study can be 

used to quantitatively determine if the Cost-Benefit test may be applicable at your facility. 

The requirements of the Benefits Valuation Study are outlined in Appendix A of this report. 

Valuation of the benefits is not within the scope of this evaluation. 
70

Table 6-1 EPA Cost Modules 

Cost Module Technology Description 

1 Addition of fish handling and return system to 

an existing traveling screen system 

2 Addition of fine-mesh screens to an existing 

traveling screen system 

3 

Addition of a new, larger intake with fine-mesh 

and fish handling and return system in front of 

an existing intake system 

4 

Addition of passive fine-mesh screen system 

(cylindrical wedge wire) near shoreline with 

mesh width of 1.75 mm 

5 Addition of a fish net barrier system 

6 Addition of an aquatic filter barrier system 

7 

Relocation of an existing intake to a submerged 

offshore location with passive fine-mesh screen 

inlet with mesh width of 1.75 mm 

8 Addition of a velocity cap inlet to an existing 

offshore intake 

9 

Addition of passive fine-mesh screen to an 

existing offshore intake with mesh width of 

1.75 mm 

10 Module 10 not used in the final rulemaking 

11 

Addition of dual-entry, single-exit traveling 

screens (with fine- mesh) to a shoreline intake 

system 

12 

Addition of passive fine-mesh screen system 

(cylindrical wedge wire) near shoreline with 

mesh width of 0.76 mm 

13 

Addition of passive fine-mesh screen to an 

existing offshore intake with mesh width of 0.76 

mm 

14 

Relocation of an existing intake to a submerged 

offshore location with passive fine-mesh screen 

inlet with mesh width of 0.76 mm 
71 

Table 6-2 Cost EPA Estimated for Harbor Generating Station 

Facility ID DUT1138 Intake ID 

- 

Assumed design intake flow (gpm ) (Xepa) 77,083 

Actual design intake flow (gpm) ((Xf) 75,000 

Capital cost $264,532 Baseline O&M annual cost $12,475 Post construction O&M annual cost $37,753 Annualized capital + net O&M using EPA design intake flow (Yepa) $62,942 

Net revenue losses from net construction down time Pilot study costs - Annualized down time and pilot study costs - Performance standards on which EPA bases its cost estimates I Actual performance standard required I/E EPA-modeled technology 1 Design flow adjustment slope (m) 1.1604 EPA cost used as basis for rule (Yepa) $62,942 

Adjusted EPA costs for Compliance Alternative 5 (Yf) $130,007 
72 

Table 6-3 Alden’s Appraisal Level Costs of Evaluated Alternatives 

 Estimated from Alden Database 

Alternative 

Construction 

Costs 

(2002 $) 

Replacement 

Power 

During 

Shutdown 

(MWh) 

Total 

Capital Cost 

( 2002 $)1

O&M 

Costs 

(2002 $) 

Lost 

Generation 

(MWh) 2

Annualized 

Capital 

Costs 

(2002 $)3

Annualized 

O&M Costs 

(2002 $)1, 2

Total 

Annualized 

Costs 

(2002 $) 

Retrofit Screenhouse with Fine-Mesh 

Ristroph Screens $1,730,000 0 $1,730,000 $210,000 1,051 $246,000 $240,000 $486,000 

Install Narrow-Slot Wedge wire in front 

of the Existing CWIS $3,100,000 0 $3,100,000 $40,000 43 $441,000 $29,000 $470,000 

Existing Operations $0 0 $0 $0 0 $0 $0 $0 

Retrofit Plant with Closed-Cycle 

Cooling System4 $15,000,000 105,000 $19,200,000 $300,000 4,610 $2,734,000 $472,000 $3,206,000 

1. Based off a cost for lost generation of $40 per MWh 2. Includes costs as a result of any power penalties associated with the technology 3. Alden assumed a discount rate of 7%, and an amortization rate of 10 years for the capital costs and 30 years for the pilot study and downtime costs 

4. Cooling tower costs based off of EPRI study (EPRI 2002a). 
73

Table 6-4 Comparison of Alden and EPA Permitting and Monitoring Costs 

Activity Alden (Entrainment) EPA (Estuary/Tidal 

River) 

Start-up activities $5,000–$15,000 $2,297 

Source water physical data $1,000–$3,000 $11,105 

Cooling water intake structure data $1,000–$3,000 

Cooling water system data $2,000–$5,000 

CDS Requirements 

Proposal for Information Collection $20,000–$35,000 $13,740 

Source waterbody flow information $1,000–$2,000 $0 

Impingement Mortality and/or 

Entrainment Characterization Study1

$100,000–$200,000 

$963,501 

Technology and Compliance 

Assessment Information 

Design and Construction Technology 

Plan 

$10,000–$20,000 

$6,751 

Technology Installation and Operation 

Plan 

$10,000–$25,000 

 

Pilot studies2

 $0–$350,000 $533,8081

Restoration plan $10,000–$50,000 

Information to Support Site-specific 

Determination of BTA 

 

Comprehensive Cost Evaluation Study $2,000–$4,000 

Benefits Valuation Study $1,000–$2,000 

Site-Specific Technology Plan $10,000–$25,000 

Verification Monitoring Plan3

 $5,000–$15,000 $6,667 

1. Minimum cost assumes 1 year of impingement and entrainment sampling. Maximum cost assumes two 

years of impingement and entrainment sampling. This does not include survival evaluations or waterbody 

characterization studies. 

2. Minimum cost assumes that no pilot studies would be required. Maximum cost assumes a one year pilot 

study with Ristroph screens. 

3. Does not include actual verification monitoring. 
74

Section 7 

CONCLUSIONS 

7.1 Phase II Facility Determination 

Harbor meets EPA’s definition of a Phase II Facility and will be subject to all the rules 

applicable to Phase II facilities. Harbor withdraws water from the ILAHC and has a capacity 

factor greater than 15%, therefore the facility will be subject to both the impingement mortality 

and entrainment standards. 

7.2 Applicability of Compliance Alternatives 

Compliance Alternative 1

Harbor Units 10-14 are closed-cycle units and would therefore already meet the IM&E 

standard. Units 1&2 would also meet the IM&E standard as they do not require cooling 

water. If Unit 5 were to meet both the IM&E standards with closed-cycle cooling towers 

the annualized cost is estimated to be $3,206,000. The CWIS and screenhouse would 

already meet the IM standard as the existing through-screen velocity is less than 0.5 ft/sec 

Compliance Alternative 2

The information provided to the Team indicates that the current operation of Harbor may 

meet both performance standards. The current Unit 5 flow is only 16% of the 

hypothetical baseline flow that would occur if all operating units at harbor were designed 

as once-through units. This would result in a reduction in entrainment of about 84%, 

which meets the E reduction standard. The CWIS and screenhouse should meet the IM 

reduction standard by applying Compliance Alternative 1, as stated above. 

Compliance Alternative 3

Harbor could achieve the performance standard via a technological, operational, and/or 

restoration measure used alone or in combination with existing technologies, operational 

measures, and/or restoration measures at the facility. Section 4summarizes the 

technological and operational options that hold the greatest potential for meeting the 

performance standards. Restoration is summarized separately in Section 5. 

Compliance Alternative 4

The existing pre-approved technology (submerged cylindrical wedge wire screens) is preapproved for use in freshwater rivers or streams only. Since Harbor is not located on a 

freshwater river or stream, this option is currently unavailable for Harbor. 

Compliance Alternative 5
75

A Site-specific determination of BTA can be granted to any facility that passes either the 

Cost-Cost or the Cost-Benefit tests as discussed in Section 6.4 and 6.5. There is not 

sufficient information available at this time to determine if Harbor would pass either test. 

While the costs of the technologies Alden evaluated are at least two times the EPA cost, 

EPA has not defined “significantly greater than.” Therefore, it is not possible to 

determine, with any certainty, when the “significantly greater than” threshold has been 

exceeded. 

The applicability of a site-specific BTA determination based on the Cost-Benefit test is 

out of the scope of this evaluation. LADWP should consider the applicability of the 

Cost-Benefit test following IM&E sampling. Once current data are available, they can be 

used to estimate equivalent adults (EA) and production forgone (PF) losses. 

7.3 Compliance Methods 

The Team evaluated intake technologies, modified operations, and restoration alternatives for 

Harbor. A summary of these alternatives, along with expected effectiveness, is shown below. 

7.3.1 Technologies and Operational Measures 

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

considered by LADWP to meet the IM&E standards at Harbor is presented in this report. 

Alden’s preliminary judgment on how likely these alternatives are to actually meet these 

standards is summarized as follows: 

Alternative 

Will It Meet The 

Impingement Mortality 

Reduction Standard? 

Will It Meet The 

Entrainment Reduction 

Standard? 

Fine Mesh Ristroph Screens Yes, provided that impingement 

survival of key species is at least 

80% 

Yes. 

Narrow-Slot Wedge Wire Screens Yes Yes 

Existing Facility Operations Yes, the through screen velocity is 

less than 0.5 ft/sec 

Yes, if the existing operations 

provide a flow reduction of 

greater than 60% from a 

hypothetical baseline flow. 

Closed-Cycle Cooling Yes Yes 

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

the Rule are: 
76

Alternative Alden Annualized Costs EPA’s Annualized Costs 

Fine Mesh Ristroph Screens $486,000 

Narrow-Slot Wedge Wire 

Screens 

$470,000 

Existing Facility Operations $0 

Closed-Cycle Cooling $3,206,000 

$130,007 

While Alden’s cost analysis was done on a preliminary basis, the comparison of the costs 

indicates that if LADWP were to install a fish protection technology at Harbor the cost of 

installing fine-mesh Ristroph screens or narrow-slot wedge wire screens may be the most costeffective technologies to meet the IM&E standards. 

7.3.2 Restoration 

Based on available information, Alden cannot compare the costs of the various technology 

options to the costs for a restoration project that would provide comparable environmental 

benefits per EPA’s proposed criteria. This is because the Team cannot estimate the requisite size 

(and associated costs) of the restoration project since current annual fish losses due to 

impingement mortality and entrainment are not known. This lack of information should not 

preclude LADWP from consulting with the agencies if a restoration option may be of corporate 

interest. Information that must ultimately be filed has been previously noted. In addition to the 

agency consultation and data gathering needs described in Appendix A, Alden recommends the 

following actions be taken prior to the development of any specific restoration project plans:

1. Calculate requisite units of restoration that would mitigate for CWIS impingement 

mortality and entrainment losses (or appropriately scale restoration such that benefits 

are “substantially similar” 15 to those which could be attained by meeting the 

applicable performance standard). 

2. Develop a restoration plan and present, including all requisite information noted 

Section 6, to CalEPA. Continue consultation and plan development until approved 

and formally included as a permit condition. 

3. Implement restoration measures- form an adaptive management plan to monitor and 

refine the restoration measure. 

The following information will have to be submitted to CalEPA for review and approval if 

LADWP wishes to include restoration measures as part of its demonstration of comparable 

performance to an intake technology: 

 

15 EPA has not give guidance on the term “substantially similar” as it pertains to the Clean Water Act. On February 11, 1991, 

EPA released a ruling on the definition of “substantially similar” and its relation to the Clean Air Act (56 FR 5352). This 

definition indicates that in relation to the oxygen content in unleaded fuel, “substantially similar” is 2.7% by weight. How this 

relates to section 316(b) of the Clean Water Act is not known. 
77

• A demonstration that LADWP evaluated other compliance measures at Harbor 

and concluded that restoration is a more feasible, cost-effective, or 

environmentally desirable alternative; 

• A list and narrative description of any existing or proposed restoration measures; 

• A quantification of the benefits resulting from implementation of a restoration 

measure along with any benefits associated with technology and/or operational 

controls. This should also include any uncertainties in the calculation of the 

benefits; 

• Design calculations, drawings, and estimates to document that the proposed 

restoration measures in combination with design and construction technologies 

and/or operational measures, or alone, will meet the requirements of the Rule; 

• An adaptive management plan for implementing and maintaining the efficacy of 

selected restoration measures used alone or in combination with control 

technologies and operational measures that have met the applicable requirements 

of the Rule; 

• A summary of any past or voluntary consultation with appropriate federal, state, 

and tribal fish and wildlife management agencies related to proposed restoration 

measures and a copy of any written comments received as a result of 

consultations; 

• A peer review of information submitted with the Restoration Plan. This would 

need to be requested by CalEPA; and 

• A description of the information to be included in a bi-annual status report to 

CalEPA 

7.4 Site-Specific Compliance Deadline 

Harbor’s permit expires on (June 10, 2008) which is less than four years after the finalization of 

the Rule. Therefore, LADWP should to request an extension to its submission schedule. 

Based on EPA’s compliance timeline, LADWP would need to submit the Proposal for 

Information Collection twenty-one months prior to the permit expiration date. Once comments 

are received, LADWP can proceed with the remaining application materials including: 1) Source 

Water Physical Characterization Study, 2) Cooling Water Intake Structure Data, 3) Cooling 

System Data, and 4) CDS. This information is due 180 days prior to the permit expiration date. 

Alden believes that this schedule is somewhat idealistic as IM&E sampling would require 

several years of data to properly conduct the study. Therefore, LADWP should start the 

permitting process as soon as possible. 

7.5 Overview of Compliance Options 

If LADWP chooses not to apply Compliance Alternative 1 via closed-cycle cooling at Harbor, 

then it should prepare the Proposal for Information Collection, included in the study should be 

the details of an IM&E sampling program. This sampling program should collect 1-2 years of 

data. These data could be used to help LADWP determine which of the compliance alternatives 

are applicable to Harbor. Depending on which compliance alternative LADWP selects for 
78

Harbor, the permitting and monitoring costs could vary significantly. The following table 

represents EPA’s Permitting and Monitoring Cost for an estuary site versus Alden’s estimated 

Permitting and Monitoring Cost ranges for different compliance alternatives. The EPA cost does 

not take into consideration costs for several of the studies that LADWP may face at Harbor, 

including: Cooling Water Intake Structure Data, Cooling Water System Data, the TIOP, pilot 

study costs, a Restoration Plan, Comprehensive Cost Evaluation Study, Benefits Valuation 

Study, Site-Specific Technology Plan. 

Compliance Alternative Alden Cost Range EPA Maximum 

Expected Cost 

1 $10,000 - $30,000 

2 $170,000 - $700,000 

3 $170,000 - $700,000 

4 N/A 

5 $170,000 - $270,000 

$1,004,061

From this preliminary analysis it appears that the existing operation of Harbor should meet the 

performance standard via Compliance Alternative 2. However, EPA allows states to set 

alternative regulatory requirements that are as strict or stricter then those required by the Rule. 

CalEPA may impose additional requirements at Harbor beyond what would be required by EPA 

under Compliance Alternative 2. 

79

Section 8 

REFERENCES 

Bailey, D. E., J. J. Loos, E. S. Perry, R. J. Wood. 2000. A retrospective evaluation of 316(b) 

mitigation options using a decision analysis framework. Pages S25-S36 in D. A. Dixon, D. E. 

Bailey, C. Jordan, J. Wisniewski, J. R. Wright, Jr., and K. D. Zammit (Editors). Power Plants & 

Aquatic Resources: Issues and Assessment. Environmental Science & Policy 3(Supplement 1). 

CDFG/NMFS (California Department of Fish and Game and National Marine Fisheries Service). 

2001. Final report on anadromous salmonid fish hatcheries in California. Joint Hatchery 

Review Committee, Sacramento, CA. December 3, 2001 (report can be downloaded from: 

http://www.dfg.ca.gov/lands/fish1.html). 

Consolidated Edison Company of New York, Inc. 1994. Evaluation of Underwater Sound to 

Reduce Impingement at the Arthur Kill Station. 

Davis, R. W., J. A. Matuousek, M. J. Skelly and M. R. Anderson. 1988. Biological Evaluation 

of Brayton Point Station Unit 4 Angled Screen Intake. In: Fish Protection at Steam and 

Hydroelectric Power Plants, San Francisco, CA, October 28-31, 1987. Sponsored by Electric 

Power Research Institute (EPRI). CS/EA/AP-5663-SR. 

Deysher, L. E., et al. 2002. Design considerations for an artificial reef to grow giant kelp 

(Macrocystis pyrifera) in Southern California. ICES Journal of Marine Science 59: S201-S207 

Duke Energy Morro Bay LLC. 2002. Morro Bay Power Plant Modernization Project. Habitat 

Enhancement Program. Morro Bay, California. Report can be downloaded at: http://www.dukeenergy.com/businesses/plants/own/us/western/morrobay/reports/

Dunning, D. 1995. Ultrasound Deterrence: Alewife at a Nuclear Generating Station in New 

York. In T. J. Carlson and A. N. Popper (eds.): Using Sound to Modify Fish Behavior at PowerProduction and Water-Control Facilities: A Workshop. Prepared for U.S. Department of Energy 

and Bonneville Power Administration, DOE/BP-62611-11. 

Electric Power Research Institute (EPRI). 1994. Research Update on Fish Protection 

Technologies For Water Intakes. TR-104122. 

EPRI. 1998. Evaluation of Fish Behavioral Barriers. TR-109483. 

EPRI. 1999. Fish Protection at Cooling Water Intakes: Status Report. TR-114013. 

EPRI. 2002a. Cooling System Retrofit Cost Analysis. Report 1007456. July 2002. Palo Alto, 

CA 

EPRI. 2002b. Guidelines for Selection of 316(b) Assessment Method or Model. Report 

1005176, May 2002. Palo Alto, CA. 
80

EPRI. 2003a. Enhancement Strategies for Mitigating Potential Operational Impacts of Cooling 

Water Intake Structures: Final Technical Report. Report 1007454. June 2003. Palo Alto, CA. 

EPRI. 2003b. Laboratory Evaluations of Wedgewire Screens for Protecting Early Life Stages of 

Fish at Cooling Water Intakes, EPRI, Palo Alto, CA: 2003. 1005339. 

Fox, D. A., J. E. Hightower, and F. M. Parauka. 2002. Estuarine and nearshore marine habitat 

use by Gulf sturgeon from the Choctawhatchee River System, Florida. Pages 111-126 in W. Van 

Winkle, P. Anders, D. Secor, and D. Dixon, editors. Biology, Management, and Protection of 

North American Sturgeon. American Fisheries Society Symposium 28, Bethesda, MD. 

Goodyear, C. P. 1978. Entrainment impact estimates using the equivalent adult approach. 

Report No. FWS/OBS-78/65. U.S. Fish and Wildlife Service, Washington, D.C. 

Hendricks, M. L. 1995. The contribution of hatchery fish to the restoration of American shad in 

the Susquehanna River. Pages 329-336 in H. L. Schramm, Jr. and R. G. Piper, editors. Uses and 

effects of cultured fishes in aquatic ecosystems. American Fisheries Society Symposium 15, 

Bethesda, Maryland, USA 

Jensen, A. L., R. H. Reider, and W. P. Kovalak. 1988. Estimation of production foregone. 

North American Journal of Fisheries Management 8: 191-198. 

Kneib, R. T. 2003. Bioenergetic and landscape considerations for scaling expectations of nekton 

production from intertidal marshes. Marine Ecology Progress Series 264: 279-296. 

LaJeone, L. J., and R. G. Monzingo. 2000. 316(b) and Quad Cities Station, Commonwealth 

Edison Company. Pages S313-S322 in D. A. Dixon, D. E. Bailey, C. Jordan, J. Wisniewski, J. R. 

Wright, Jr., and K. D. Zammit (Editors). Power Plants & Aquatic Resources: Issues and 

Assessment. Environmental Science & Policy 3(Supplement 1). 

McCay, D. P. F., and J. J. Rowe. 2003. Habitat restoration as a mitigation for lost production at 

multiple trophic levels. Marine Ecology Progress Series 264: 233-247. 

Mettee, M. F., and P. E. O’Neil. 2003. Status of Alabama shad and skipjack herring in Gulf of 

Mexico drainages. Pages 157-170 in K. E. Limburg and J. R. Waldman (Editors). Biodiversity, 

status, and conservation of the world’s shads. American Fisheries Society Symposium 35, 

Bethesda, Maryland, USA. 

NOAA. 1997. Scaling compensatory restoration actions. U. S. Department of Commerce, 

National Oceanic and Atmospheric Administration – Damage Assessment and Restoration 

Program, Silver Spring, Maryland. See also: 

http://www.nmfs.noaa.gov/habitat/restoration/projects_programs/darp/index.html

Pejchar, L., and K. Warner. 2001. A river might run through it again: criteria for consideration 

of dam removal and interim lessons from California. Environmental Management 28(5): 561-

575. 
81

Peterson, C. H., and R. N. Lipcius. 2003. Conceptual progress toward predicting quantitative 

ecosystem benefits of ecological restorations. Marine Ecology Progress Series 264: 297-307. 

Peterson, C. H., J. H. Grabowski, and S. P. Powers. 2003. Estimated enhancement of fish 

production resulting from restoring oyster reef habitat: quantitative valuation. Marine Ecology 

Progress Series 264: 249-264 – 

Peterson, C. H., R. T. Kneib, and C-A. Manen. 2003. Scaling restoration actions in the marine 

environment to meet quantitative targets of enhanced ecosystem services. Marine Ecology 

Progress Series 264: 173-175. 

Ploskey, G. R., J. M. Nestler, G. N. Weeks, and C. Schilt. 1995. Evaluation of an Integrated 

Fish-Protection System. Waterpower 95, Proceedings of the International Conference on 

Waterpower. American Society of Civil Engineers, New York, NY. 

Powers, S. P., J. H. Grabowski, C. H. Peterson, and W. J. Lindberg. 2003. Estimating 

enhancement of fish production by offshore artificial reefs: uncertainty exhibited by divergent 

scenarios. Marine Ecology Progress Series 264: 265-277. 

Rago, P. J. 1984. Production foregone: an alternative method for assessing the consequences of 

fish entrainment and impingement losses at power plants and water intakes. Ecological 

Modelling 24: 79-111. 

Reed, D., S. Schroeter, and M. Page. 2002. Proceedings from the second annual public 

workshop for the SONGS Mitigation Project. San Clemente, CA, February 27, 2002. Submitted 

to the California Coastal Commission by the Marine Science Institute, University of California, 

Santa Barbara. April 3, 2002. 

St. Pierre, R. A. 2003. A case history: American shad restoration on the Susquenhanna River. 

Pages 315-322 in K. E. Limburg and J. R. Waldman (Editors). Biodiversity, status, and 

conservation of the world’s shads. American Fisheries Society Symposium 35, Bethesda, 

Maryland, USA. 

Strange, E., H. Galbraith, S. Bickel, D. Mills, D. Belton, and J. Lipton. 2002. Determining 

ecological equivalence in service-to-service scaling of salt marsh restoration. Environmental 

Management 29(2): 290-300 

Tatham, T. R., D. L. Thomas, and G. J. Miller. 1978. Survival of Fishes and Macroinvertebrates 

Impinged at Oyster Creek Generating Station. In: Fourth National Workshop on Entrainment and 

Impingement, Chicago, IL, December 5, 1977. Sponsored by Ecological Analysts, Inc. 

U.S. Fish & Wildlife Service (USFWS). 2001. Partners for Fish and Wildlife: California. 

Partners for Fish and Wildlife Program, Sacramento, CA. 

United States Environmental Protection Agency (EPA). 2004a. National Pollutant Discharge 

Elimination System - Final Regulations to Establish Requirements for Cooling Water Intake 
82

Structures at Phase II Existing Facilities. July 9, 2004 Federal Register: Vol. 69, No. 131 Pg 

41576-41693

United States Environmental Protection Agency (EPA). 2004b. Technical Development 

Document for the Final Section 316(b) Phase II Existing Facilities Rule. February 12, 2004. 

EPA 821-R-04-007 DCN 6-0004 

Weinstein, M. P., et al. 2001. Restoration principles emerging from one of the world’s largest 

tidal marsh restoration projects. Wetlands Ecology and Management 9: 387-407 

Weisberg, SB., et al. 1984. The effects of screen slot size, screen diameter, and through-slot 

velocity on entrainment of estuarine ichthyoplankton through wedgewire screens. Martin 

Marietta Environmental Systems. August 1984. 
A-1 

APPENDIX A

OVERVIEW OF THE RULE 

A.2 Basic Requirements 

Recently promulgated guidance for the implementation of Section 316(b) of the Clean Water Act 

set national performance standards to minimize adverse environmental impacts caused by water 

withdrawals. This report addresses the Phase II Existing Facilities portion of the Rule. 

A.2.1 Applicability of the Rule 

The Rule applies to existing Phase II facilities. EPA defines “existing facility” and “Phase II 

facility” separately. Both definitions appear in Section 125.93 of the Rule. EPA defines an 

existing facility as: 

• Any facility that commenced construction before January 17, 2002; 

• Any modification of such a facility or any addition of a unit at such a facility that does 

not meet the definition of a new facility as outlined in §125.83 of the Rule; 

• Any addition of a unit at such a facility for purposes of the same industrial operation; 

• Any addition of a unit at such a facility for purposes of a different industrial operation, if 

the additional unit uses an existing cooling water intake structure and the design capacity 

of the intake structure is not increased; or 

• Any facility constructed in place of such a facility if the newly constructed facility uses 

an existing cooling water intake structure whose design intake flow is not increased to 

accommodate the intake of additional cooling water.

EPA defines a Phase II facility as a point source where the primary activity is to generate and 

transmit electric power or generate electric power for sale to another entity for transmission; that 

uses or proposes to use one or more cooling water intake structures (CWISs) with a total design 

intake flow of 50 million gallons per day (MGD) or more to withdraw cooling water from waters 

of the United States; and that uses at least 25% of water withdrawn exclusively for cooling 

purposes. 

A.2.2 Core Requirements 

EPA’s preferred alternative involves the use of national performance standards (i.e., a reduction 

in impingement mortality (IM) of all life stages of fish and shellfish of 80–95% from the 

“calculation baseline” and at some facilities, a reduction in entrainment of all life stages of fish 

and shellfish by 60–90% from the “calculation baseline” (EPA 2004a § 125.94[b]). Facilities 

that EPA requires to meet the entrainment reduction standard are those facilities that have a 
A-2 

capacity utilization rate1

 of 15% or greater and withdraw water from a tidal river, estuary, ocean, 

or Great Lake. Both the IM and entrainment standards apply to facilities that are located on a 

freshwater river and have a design intake flow greater than 5% of the mean annual river flow. A 

summary of which performance standards apply to each waterbody appears in Table A-1. 

The “calculation baseline” is an estimate of IM&E that would occur at a facility if it were 

designed and operated in the following ways: 

• The cooling water system is designed as a once-through system. 

• The opening of the cooling water intake structure is located at the shoreline near the 

surface of the source waterbody and the face of the standard 3/8-inch mesh traveling 

screen is oriented parallel to it. 

• The baseline practices, procedures, and structural configuration are those that a facility 

would maintain in the absence of any structural or operational controls that would reduce 

IM&E, including flow or velocity reductions, implemented in whole or in part for the 

purposes of reducing IM&E. 

EPA has allowed for some flexibility in the “calculation baseline” at the facility level. EPA 

allows a facility to use the current level of IM&E as the “calculation baseline.” This could 

potentially streamline the permit application since the facility could determine the baseline using 

data collected during the IM&E Study (a requirement of the CDS, as we describe below). A 

facility may also request that an alternative intake location be used (e.g., at a depth other than at 

or near the surface or at a location other than the shoreline) if the utility can demonstrate to the 

Director that the alternate location would correspond to a higher baseline level of IM and/or 

entrainment. 

A facility may estimate the “calculation baseline” using: 1) historical IM&E data from a facility; 

2) IM&E data from another facility with comparable design, operational, and environmental 

conditions; 3) current biological data collected in the waterbody near the CWIS; or 4) current 

IM&E data collected at a facility. 

 

1

 Capacity utilization rate is the ratio between the average annual net generation of power by the facility (in MWh) 

and the total net capability of the facility to generate power (in MW) multiplied by the number of hours during a 

year. In cases where a facility has more than one intake structure, and each intake structure provides cooling water 

exclusively to one or more generating units, the facility may calculate the capacity utilization rate separately for 

each intake structure based on the capacity utilization of the units it services. The EPA would then determine 

applicable requirements under this subpart separately for each intake structure. The facility should measure the 

average annual net generation over a 5-year period (if available) of representative operating conditions, unless the 

facility makes a binding commitment to maintain capacity utilization below 15% for the life of the permit, in which 

case it may base the rate on this commitment. For purposes of this regulation, the capacity utilization rate applies to 

only that portion of the facility that generates electricity for transmission or sale using a thermal cycle employing the 

steam water system as the thermodynamic medium (EPA 2004a § 125.93). 
A-3 

A.2.3 Alternate/Amended Requirements 

Under special circumstances, a regulatory agency may apply alternative regulatory requirements 

to a facility. A state that oversees State Pollutant Discharge Elimination System (SPDES) 

permits may apply alternative standards that are equal to or more stringent than those in the Rule. 

Agencies may also impose alternative regulatory requirements at a nuclear facility if the facility 

can demonstrate to the Director, based on consultation with the Nuclear Regulatory Commission 

(NRC), that compliance with the performance standards could compromise safety requirements 

established by the NRC. The Director would then have to make a site-specific BTA 

determination that would not result in a conflict with the NRC’s safety requirements. EPA also 

allows states to establish programs for the trading of compliance credits within a watershed that 

would result in an environmental performance that compares to the reductions of IM&E that a 

facility would otherwise achieve under the Rule. EPA recommends that states base their trading 

programs on an organism-for-organism basis rather then an organism-for-pollutant reduction 

basis. Currently, no established trading programs exist. The Administrator would need to 

approve any trading program.

A.3 Methods for Compliance 

There are five compliance alternatives that EPA indicates a facility may use to comply with 

§316(b) of the Clean Water Act. All five compliance options, as stated by EPA, will achieve a 

reduction in impingement mortality by 80–95% and entrainment (where applicable) by 60–90% 

(or equivalent environmental benefit) for all Phase II Existing Facilities. We present the five 

compliance options in §125.94 of the Rule and describe it in detail in Sections 2.2.1 through 

2.2.5 

A.3.1 Flow Commensurate with Closed-Cycle Cooling or 0.5 ft/sec Through-Screen 

Velocity (Compliance Alternative 1) 

Two methods exist for complying with Compliance Alternative 1. The first method is to 

demonstrate that a facility has or will reduce intake flow commensurate with a closed-cycle 

system. Using closed-cycle cooling reduces intake flow by 70–98% compared to a once-through 

system, depending on the cycles of concentration of the cooling system. EPA assumes that 

impingement mortality and entrainment would be reduced by the same amount. EPA deems 

such a reduction in flow as satisfying the applicable IM&E performance standard for all 

waterbodies. EPA will not require a facility that has installed or will install a closed-cycle 

system to submit a CDS. A second method for complying using Compliance Alternative 1 

allows a facility to meet the IM standard by having or reducing design intake velocity2

 to 0.5 

ft/sec or less. A facility that reduces the design intake velocity would not have to submit CDS 

 

2

 EPA defines design intake velocity as the value assigned (during the design of a CWIS) to the average speed at 

which intake water passes through the open area of the intake screen (or other device) against which organisms 

might be impinged or through which they might be entrained. Alden believes that this synonymous with throughscreen velocity. 
A-4 

information pertaining to IM. However, if the facility has to comply with both the IM and 

entrainment standards, EPA would require all the CDS information pertaining to entrainment. 

A.3.2 Existing Intake Meets the Standards (Compliance Alternative 2) 

Under the second Compliance Alternative, a facility may meet the performance standards by 

demonstrating that existing design and construction (D&C) technologies and/or restoration 

measures meet the applicable performance standards. 

A.3.3 Proposed Technology, Operation, and/or Restoration to Meet the Standard 

(Compliance Alternative 3) 

The third Compliance Alternative allows a utility to comply by demonstrating that the facility in 

question will meet the applicable performance standards by implementing D&C technologies 

and/or restoration measures. EPA defines technologies as physical modifications to the intake 

(e.g., fine mesh screens, wedge wire screens, fish handling and return systems, aquatic filter 

barrier systems, etc.). Examples of operational measures include seasonal flow reductions, a 

reduction in velocity, installation of variable speed pumps, and adjustment of maintenance 

shutdowns, etc. Finally, a facility may use restoration that produces a level of organisms in the 

waterbody that is “substantially similar” to that which would result from meeting the applicable 

performance standards. A facility could use all three of these methods alone or in conjunction 

with each other to meet the performance standards. 

A.3.4 EPA-Approved Technology (Compliance Alternative 4) 

The Rule states that a facility may demonstrate to the Director that it has installed and is properly 

operating and maintaining a Rule-specified and approved D&C technology in accordance with 

§125.99(a). 

EPA currently has one pre-approved technology for compliance: submerged cylindrical wedge 

wire screens in freshwater rivers or streams. The Director may approve additional technologies 

if it is demonstrated that the technology in question can “consistently meet” the performance 

standards. 

A facility may use submerged cylindrical wedge wire screens when its CWIS is located in a 

freshwater river or stream, where there is a sufficient ambient current to properly clean the 

screens, where the maximum through-slot velocity is 0.5 ft/sec, where the slot size is protective 

of all the species and life stages that require protection, and where all the condenser cooling 

water flows through the wedge wire screens. A facility can use this alternative to meet both the 

IM and entrainment standards. If a facility need only meet the IM standard, then wedge wire 

screens would meet the requirements of Compliance Alternative 1 (0.5 ft/sec through-screen 

velocity). Facilities where both the IM&E standards apply would need to conduct verification 

monitoring of entrainable organisms. 
A-5 

In addition, under this Compliance Alternative, a facility or other interested persons may submit 

a request to the Director for approval of a different technology. If the Director approves the 

technology, all facilities with similar site conditions under his or her jurisdiction may use it, if 

the State’s administrative procedures allow it. Requests for approval of a technology submitted 

to the Director must include a detailed description of the technology, a list of design criteria for 

the technology and site characteristics, and conditions that each facility must possess in order to 

ensure that the technology can consistently meet the performance standards at any facility with 

applicable design criteria, site characteristics, and conditions. Prior to approving a technology, 

the Director must allow public notice and opportunity for comments on the approval of the 

technology. 

A.3.5 Site-Specific BTA (Compliance Alternative 5) 

The Rule includes two methods for a facility to obtain a site-specific BTA determination: the 

Cost-Cost and Cost-Benefit tests. Both tests are fundamentally similar in that they compare the 

site-specific costs necessary to meet the applicable national performance standards to either the 

costs that EPA estimated for a like facility in calculating the national costs or the benefits that a 

facility would achieve by complying with the performance standards. If the site-specific costs 

are “significantly greater than” EPA’s costs or the benefits that a facility would attain, then the 

Director can make a site-specific BTA determination. EPA, however, has not explicitly defined 

“significantly greater than.” Therefore, until additional guidance is provided by EPA, it may be 

difficult, if not impossible, to determine if a facility satisfies the requirements of the Cost-Cost or 

Cost-Benefit tests. 

If a facility chooses to use the Cost-Cost test, EPA will require it to submit two additional studies 

with the CDS. These studies are the Comprehensive Cost Evaluation Study and a Site-Specific 

Technology Plan. For a facility choosing to use the Cost-Benefit test, a third study would need 

to be included: the Benefits Valuation Study. A summary of these studies appear in Section 

2.3.2. 

A.4 Information Requirements 

The Rule requires substantial engineering and biological information to establish a baseline; to 

determine which of the performance standards are applicable; to justify the selection of BTA; 

and, subsequently, to monitor the performance of the selected operational, technological, and/or 

restoration measure the facility will use to meet the performance standards. A utility will need to 

develop and present considerable data and studies during the permit renewal process and must 

maintain extensive ongoing management of selected alternatives. 

A.4.1 Date Required Prior to the Expiration of the Current Permit 

To determine which standards will apply at a given facility, EPA requires the permittee to 

submit, 180 days prior to expiration of a permit, the following three study components: 1) Source 

Water Physical Characterization Study, 2) Cooling Water Intake Structure Data, and 3) Cooling 

System Data as we summarize in Table A-2. 
A-6 

A.4.2 Comprehensive Demonstration Study (CDS) 

EPA requires all facilities, except those that meet BTA requirements by having flow 

commensurate with closed-cycle cooling, to submit a CDS. The CDS may include the following 

informational and study components: 

• Proposal for Information Collection 

• Source Waterbody Flow Information 

• Impingement Mortality and/or Entrainment Characterization Study 

• Technology and Compliance Assessment Information 

3⁄4 Design and Construction Technology Plan 

3⁄4 Technology Installation and Operation Plan 

• Restoration Plan 

• Information to Support a Site-Specific Determination of BTA 

3⁄4 Comprehensive Cost Evaluation Study (Cost-Cost and Cost-Benefit test) 

3⁄4 Valuation of Monetized Benefits of Reducing IM&E (Cost-Benefit test only) 

3⁄4 Site-Specific Technology Plan 

• Verification Monitoring Plan 

The purpose of the CDS is to characterize the current level of IM&E, to describe the operation of 

the CWIS, and to confirm that the current configuration and operation or options a facility selects 

and installs meet the applicable national performance standards or those the Director requires for 

a site-specific BTA determination. The requirements of the CDS would vary depending upon 

which Compliance Alternative the facility pursues (Table A-3). We describe the individual 

components of the CDS below. 

Proposal for Information Collection 

The Proposal for Information Collection (PIC) is a description of the information necessary to 

support the CDS and the methods used to gather any additional information. This study 

includes: 

• A description of the proposed and/or implemented technologies, operational measures, 

and/or restoration measures evaluated in the CDS; 

• A list and description of any historical studies characterizing IM&E and/or the physical 

and biological conditions in the vicinity of the CWIS and their relevance to the CDS; 

• A summary of any past or ongoing consultations with appropriate federal, state, and tribal 

fish and wildlife agencies that are relevant to the CDS, including a copy of written 

comments received as a result of such consultations; and 

• A sampling plan for any new field studies the facility will conduct in order to ensure 

sufficient data exists to develop a scientifically valid estimate of IM&E at a facility. 
A-7 

Source Waterbody Flow Information 

The information necessary for the Source Waterbody Flow Information would depend upon the 

waterbody from which the CWIS withdraws water: 

If the CWIS located on a freshwater river or stream, the following information is necessary: 

• The mean annual flow of the waterbody (from a period of time up to 10 years, if 

available). 

• Supporting documentation and engineering calculations necessary to determine if the 

design intake flow of the CWIS is greater than 5% of the mean annual flow of the river or 

stream for purposes of determining applicable performance standards (the facility may 

use data from USGS gaging station or actual instream flow monitoring by the facility). 

If the CWIS is located in a reservoir or lake (other than one of the Great Lakes),3

 the following 

information is necessary: 

• Where the facility proposes an increase in the CWIS design intake flow, it must describe 

the thermal stratification in the waterbody and provide any supporting documentation and 

engineering calculations to demonstrate that the total design intake flow after the increase 

will not disrupt the natural thermal stratification and turnover pattern in a way that 

adversely impacts fisheries. This includes the results of any consultations with federal, 

state, or tribal fish and wildlife management agencies. 

If the CWIS is located on an ocean or estuary, EPA does not require it to submit any source 

waterbody flow information. 

Impingement Mortality and/or Entrainment Characterization Study (IM&E Study) 

If EPA requires a facility to meet the IM reduction standard but not the entrainment reduction 

standard, the facility must submit only those components of the IM&E Study that directly relate 

to IM. 

• Taxonomic identification of all life stages of fish, shellfish, and any species protected 

under federal, state, or tribal law (including threatened or endangered species) that are in 

the vicinity of the CWIS and are susceptible to IM& E. 

• A characterization of all life stages of fish, shellfish, and any species protected under 

federal, state, or tribal law (including threatened or endangered species) identified above, 

 

3

 EPA did not request supporting documentation or engineering calculations necessary to 

determine if a facility withdraws from a river or a reservoir (i.e., retention time). To calculate 

retention time, Alden expects a facility must determine annual mean flow through the waterbody 

along with the current storage volume of the waterbody. If the waterbody is a controlled 

reservoir, then EPA may allow the facility to use the average seasonal retention time. EPA, 

however, has not given any guidance on this issue. 
A-8 

including a description of their abundance and temporal and spatial characteristics in the 

vicinity of the CWIS. The facility must base this information on sufficient data to 

characterize annual, seasonal, and diel variations in IM&E (e.g., related to climate and 

weather differences, spawning, feeding, and water column migration). The facility may 

use historical data that are representative of the current operation of the facility and of 

biological conditions at the site if appropriate. 

• Documentation of the current IM&E of all life stages of fish, shellfish, and any species 

protected under federal, state, or tribal law (including threatened or endangered species) 

identified above and an estimate of IM&E for the facility to use as the “calculation 

baseline.” The facility may use historical data that are representative of the current 

operation of the facility and of biological conditions at the site if appropriate. The facility 

must collect the data during periods of representative operational flows for the CWIS and 

must document the flows associated with the samples. 

Technology and Compliance Assessment Information 

Design and Construction Technology Plan (D&C Technology Plan)

Design and construction (D&C) technologies include both fish protection technologies and 

operational changes designed to reduce IM&E. D&C technologies do not include restoration. 

The D&C Technology Plan provides EPA with information on the fish protection technologies 

and/or operational measures the facility is currently using or planning to use to meet the national 

performance standards at each CWIS. 

• The D&C Technology Plan must include all the data and engineering calculations 

necessary to calculate the capacity utilization rate for a facility (or individual CWIS 

where applicable), including average annual net generation (MWh) (averaged over 5 

years, if available) and total net capacity of facility (MW). In addition, the plan must 

explain the technologies and/or operational measures that the facility is currently using or 

planning to use to meet the national performance standards. 

• A narrative description of the design and operation of all design and construction 

technologies and/or operational measures (existing and proposed), including fish 

handling and return systems that the facility uses or will use to meet the requirements to 

reduce IM of those species the facility expects to be most susceptible to impingement. 

This should include information that demonstrates the efficacy of the technologies and/or 

operational measures for those species. 

• A narrative description of the design and operation of all D&C technologies and/or 

operational measures (existing and proposed) that a facility is currently using or planning 

to use to meet the requirements to reduce entrainment of those species the facility expects 

to be the most susceptible to entrainment, if applicable. In addition, the facility must 

provide information that demonstrates the efficacy of the technologies and/or operational 

measures for those species. 

• Calculations of the reduction in IM&E of all life stages of fish and shellfish that the 

facility would achieve by implementing the selected technologies and/or operational 
A-9 

measures based on the IM&E Study. The facility should add reductions in IM&E from 

this “calculation baseline” as a result of any D&C technologies and/or operational 

measures (recirculation of some flow) it has already implemented at the facility to the 

reductions the facility expects to achieve by any additional design and/or construction 

technologies and operational measures that it will implement. This should include any 

increases in fish and shellfish within the waterbody attributable to restoration measures.

• Design and engineering calculations, drawings, and estimates prepared by a qualified 

professional to support the descriptions.

If a facility has multiple intake structures and dedicates each to the cooling water needs of one of 

more generating units, the facility may calculate the capacity utilization rate separately for each 

structure for purposes of determining whether entrainment reduction performance standard 

apply. The facility should use the total design intake flow at all structures combined in 

determining whether the design intake flow exceeds 5% of the mean annual flow of a freshwater 

river or stream. If the capacity utilization rate for either a single intake structure, or the facility 

as a whole is 15% or greater based on the historical 5-year annual average, but the facility has 

made a binding commitment to the Director to maintain that rate below 15% for the duration of 

the permit, then the facility can base the capacity utilization rate determination on that 

commitment.

Technology Installation and Operation Plan (TIOP)

If a facility chooses Compliance Alternatives 2, 3, 4, or 5 and uses design and construction 

technologies and/or operational measures in whole or in part to comply with the applicable 

requirements of the Rule, it must submit the following information: 

• A schedule for the installation and maintenance of any new D&C technologies. This 

includes any required down time.

• A list of operational and other parameters it will monitor and the location and frequency 

with which that monitoring will occur. 

• A list of activities that the facility will undertake to ensure, to the degree practicable, the 

efficacy of D&C technologies and operational measures the facility will implement and a 

schedule for implementing them.

• A schedule and methodology for assessing the efficacy of any installed D&C 

technologies and operational measures in meeting applicable performance standards or 

site-specific requirements.

• Documentation that the appropriate site conditions exist at the facility if it chooses 

Compliance Alternative 4 (EPA-approved technology).

Restoration Plan 

If the facility plans to use restoration measures in whole or in part to meet the applicable 

performance standards, it must submit the following information with the application for review 
A-10 

and approval by the Director. (Restoration is part of the “design” of the CWIS, and EPA 

considers it one of several technology options available to a facility.)

• A demonstration to the Director that the facility has evaluated the use of D&C 

technologies and/or operational measures for the facility and an explanation of how the 

facility determined that restoration would be more feasible, cost-effective, or 

environmentally desirable.

• A narrative description of the design and operation of all restoration measures that the 

facility is using or will use to produce fish and shellfish. If the facility uses existing 

restoration to compensate for environmental impacts other than the impacts from IM&E, 

then the facility cannot count these benefits toward meeting the applicable performance 

standards. 

• Quantification of the ecological benefits of the proposed restoration measures. The 

facility must use information from the IM&E Study and describe the production of fish 

and shellfish that the restoration measures will achieve or are already achieving. This 

must include a discussion of the nature and magnitude of uncertainty associated with the 

performance of these restoration measures.

• Design calculations, drawings, and estimates to document that the proposed restoration 

measures, in combination with D&C technologies and/or operational measures or alone, 

will meet the requirements of the Rule. If the restoration measures address the same fish 

and shellfish species identified in the IM&E Study (in-kind restoration), then the facility 

must demonstrate that the restoration measures will produce a level of these fish and 

shellfish substantially similar to that which would result from meeting applicable 

performance standards. The facility can alternately demonstrate that the restoration 

measures will satisfy site-specific requirements established by the Director. If the 

restoration measures address fish and shellfish species different from those identified in 

the IM&E Study (out-of-kind restoration), then the facility must demonstrate that the 

restoration measures produce ecological benefits substantially similar to or greater than 

those that in-kind restoration would produce.

• A plan utilizing an adaptive management method for implementing, maintaining, and 

demonstrating the efficacy of the selected restoration measures and for determining the 

extent to which the restoration measures, alone or in combination with D&C technologies 

and/or operational measures, have met the applicable requirements of the Rule. The plan 

must include: 

3⁄4 A monitoring plan that includes a list of the restoration parameters that the facility 

will monitor, the frequency with which the facility will monitor them, and 

successful criteria for each parameter. 

3⁄4 A list of activities that the facility will undertake to ensure the efficacy of the 

restoration measures and a description of the linkages between these activities and 

the monitoring plan, including an implementation schedule. 

3⁄4 A process for revising the Restoration Plan as new information, including 

monitoring data, becomes available, or if the facility is not meeting the applicable 

Rule requirements. 
A-11 

• A summary of any past or ongoing consultation with appropriate federal, state, and tribal 

fish and wildlife management agencies on the use of restoration measures, including a 

copy of any written comments received as a result of such consultations. 

• If requested by the Director, a peer review of the items submitted for the Restoration 

Plan. The facility will chose the peer reviewers in consultation with the Director, who 

may consult with EPA and federal, state, and tribal fish and wildlife management 

agencies with responsibility for fish and wildlife potentially affected by cooling water 

intake structure(s). Peer reviewers must have appropriate qualifications (e.g., in the fields 

of geology, engineering, and/or biology, etc.) depending upon the materials they will 

review. 

• A description of the information the facility will include in a biannual status report to the 

Director.

Information to Support Site-Specific Determination of Best Technology Available for 

Minimizing Adverse Environmental Impact 

The component studies the Director requires to support a site-specific BTA determination 

would depend upon which variance test the facility is using to establish the alternative 

standards. All facilities that are seeking a site-specific BTA determination must submit the 

Comprehensive Cost Evaluation Study and the Site-Specific Technology Plan. Those 

facilities that are seeking a site-specific BTA determination based on the Cost-Benefit test 

must also submit a Benefits Valuation Study. We discuss the requirements of each of these 

studies below. 

Comprehensive Cost Evaluation Study 

The facility must provide engineering cost estimates in sufficient detail to document the costs 

of implementing D&C technologies, operational measures, and/or restoration measures 

necessary to meet the applicable performance standards. 

• A demonstration that the costs in the D&C technology plan significantly exceed either 

those considered by the Director for a similar facility in establishing the applicable 

performance standards or the benefits of meeting the applicable performance standards. 

• Engineering cost estimates in sufficient detail to document the costs of implementing the 

D&C technologies, operational measures, and/or restoration measures in a Site-Specific 

Technology Plan. 

Benefits Valuation Study 

• A description of the methodology (or methodologies) the facility uses to value 

commercial, recreational, and ecological benefits (including any non-use benefits, if 

applicable). 

• Monetized non-use benefits where the IM&E Study indicates substantial harm to 

threatened or endangered species; the sustainability of populations of important species 

of fish, shellfish, and wildlife; or the maintenance of the community structure and 

function in a facility’s waterbody or watershed. 
A-12 

• Documentation of the basis for any assumptions and quantitative estimates. If the facility 

is using an entrainment survival rate other than zero, it must submit a determination of 

entrainment survival based on a study approved by the Director. 

• An analysis of the effects of significant sources of uncertainty on the results of the study. 

• If requested by the Director, a peer review of the items submitted in the Benefits 

Valuation Study. The facility must choose the peer reviewers in consultation with the 

Director, who may consult with EPA and federal, state, and tribal fish and wildlife 

management agencies with responsibility for fish and wildlife potentially affected by 

cooling water intake structures. Peer reviewers must have appropriate qualifications 

depending upon the materials they will review. 

• A narrative description of any non-monetized benefits that the facility would realize if it 

were to meet the applicable performance standards and a qualitative assessment of their 

magnitude and significance. 

Site-Specific Technology Plan

Based on the results of the Comprehensive Cost Evaluation Study and the Benefits Valuation 

Study if applicable, the facility must submit a Site-Specific Technology Plan to the Director 

for review and approval. The plan must contain the following information: 

• A narrative description of the design and operation of all existing and proposed design 

and construction technologies, operational measures, and/or restoration measures that the 

facility has selected. 

• An engineering estimate of the efficacy of the proposed and/or implemented design and 

construction technologies or operational measures and/or restoration measures. This 

estimate must include a site-specific evaluation of the suitability of the technologies or 

operational measures for reducing IM and/or entrainment (as applicable) of all life stages 

of fish and shellfish based on representative studies (e.g., studies that have been 

conducted at cooling water intake structures located in the same waterbody type with 

similar biological characteristics) and, if applicable, site-specific technology prototype or 

pilot studies. If the facility will use restoration measures, it must provide a Restoration 

Plan. 

• A demonstration that the proposed and/or implemented D&C technologies, operational 

measures, and/or restoration measures achieve an efficacy that is as close as practicable 

to the applicable performance standards without resulting in costs “significantly greater 

than” either the costs considered by the Administrator for a similar facility in establishing 

the applicable performance standards, or as appropriate, the benefits of complying with 

the applicable performance standards at a facility. 

• Design and engineering calculations, drawings, and estimates prepared by a qualified 

professional to support the elements of the Plan.

Verification Monitoring Plan 

If a facility applies Compliance Alternatives 2, 3, 4, or 5 using D&C technologies and/or 

operational measures, it must submit a plan to conduct, at a minimum, 2 years of monitoring to 
A-13 

verify the full-scale performance of the proposed or already implemented technologies and/or 

operational measures. The plan must provide the following: 

• A description of the frequency and duration of monitoring, the parameters the facility will 

monitor, and the basis for determining the parameters and the frequency and duration for 

monitoring. The parameters selected and duration and frequency of monitoring must be 

consistent with any methodology for assessing success in meeting applicable 

performance standards in the TIOP. 

• A proposal on how the facility would identify naturally moribund fish and shellfish that 

enter the cooling water intake structure and take them into account in assessing success in 

meeting the performance standards. 

• A description of the information the facility will include in a biannual status report to the 

Director.

A.5 Compliance Determination & Timeline 

In the preamble to the Rule, EPA provides a suggested timeline for facilities to file the required 

permit application. We show this timeline in Figure A-1. Most of the information in the permit 

application is due 180 days prior to the end of the current permit term or the extended 

submission schedule, including the Source Water Physical Data, Cooling Water Intake Structure 

Data, Cooling Water System Data, and the CDS. If a facility’s permit expires within 4 years 

after the Rule is published in the Federal Register (July 9, 2008), then the facility may request a 

submission schedule that is as expeditious as it is practicable but does not exceed 3 years and 

180 days after the Rule is published in the Federal Register (January 7, 2008). 

Facilities that plan to implement a technology alternative for compliance should submit the PIC 

15 months prior to submission of the remainder of required application materials. The director 

will then review and comment on the proposal and return it to the facility as expeditiously as 

possible (i.e., within 60 days) to allow the facility to address any comments and to implement 

any required study modifications. 

EPA estimates that it will take approximately 1 year for a facility to complete all of the studies 

outlined in the Proposal for Information Collection. This number may be an understatement of 

the actual time required. The IM&E Study indicates that sampling should be sufficient to 

characterize annual, seasonal, and diel variations in IM&E. This indicates that more than one 

year of sampling may be required. Therefore, Alden believes that a facility should submit the 

PIC ahead of the EPA’s suggested schedule to allow adequate time for the IM&E study. 

For a facility to come into compliance, it must submit all of the application information 

(including the required components of the CDS), it must demonstrate compliance with one of the 

alternatives, and it must monitor compliance with the performance standard as prescribed by the 

Director. A facility may also illustrate compliance by showing that it has compiled all the 

requirements of the Technology Installation and Operation Plan or Restoration Plan and is 

assessing the success of the plan to allow for an adaptive management process to further refine 

the plan.
A-14 

Table A-1 Applicable National Performance Standards Based on Waterbody Type, 

Capacity Utilization Rate, and Design Intake Flow ((Exhibit V–1 – EPA 2004a)) 

Waterbody Type

Capacity Utilization 

Rate Design Intake Flow 

Applicable Performance 

Standard

Less than 15% N/A1 Impingement mortality only 

5% or less of mean 

annual flow 

Impingement mortality only 

Freshwater river or 

stream 

Equal to or greater 

than 15% 

Greater than 5% of 

mean annual flow 

Impingement mortality and 

entrainment 

Less than 15% N/A1 Tidal river, estuary, or Impingement mortality only 

ocean 

Equal to or greater 

than 15% 

N/A Impingement mortality and 

entrainment 

Great Lakes Less than 15% N/A Impingement mortality only 

Equal to or greater 

than 15% 

N/A Impingement mortality and 

entrainment 

Lakes or reservoirs N/A Increase in design 

intake flow must not 

disrupt thermal 

stratification except 

where it does not 

adversely affect the 

management of 

fisheries 

Impingement mortality only 

1. Determination of appropriate compliance reductions in not applicable
A-15 

Table A-2 Information Required 180 Days Prior to Permit Expiration 

(§ 122.21 (r) (2), (3), and (5) (EPA 2004a) 

Data Type 

Source Water Physical Characterization Study 

Narrative description and scaled drawings of source waterbodies: 

• Aerial dimensions 

• Depths 

• Salinity 

• Temperature regimes 

• Other documentation to support waterbody type 

Identification and characterization of hydrological and geomorphological features of the waterbody: 

• Methods and results of physical studies to determine the intake’s area of influence within the 

waterbody 

• Locational maps 

Cooling Water Intake Structure (CWIS) Data 

Narrative description of the CWIS configuration, including location on waterbody and depth 

Geographic position: degrees, minutes, and seconds of each CWIS 

Narrative description of the operation of the cooling water intake system: 

• Design intake flow 

• Daily hours of operation 

• Days per year of operation 

• Any seasonal variations in operation 

Flow distribution and water balance diagram (sources, recirculation, and discharges) 

Engineering drawings of the CWIS 

Cooling Water System Data 

Narrative description of the cooling water system in relation to the CWIS: proportion of design intake 

flow that the system uses, the number of days of the year the system operates, seasonal changes in 

operation, and the engineering calculations the facility used to derive these results 
A-16 

Table A-3 Comprehensive Demonstration Study (CDS) Requirements for Each 

Compliance Alternative (Exhibit V-2 – EPA 2004a) 

Compliance Alternative Comprehensive Demonstration Study Requirements 

1. Demonstrate facility has 

reduced flow 

commensurate with closed 

cycle recirculating system. 

None 

1. Demonstrate facility has 

reduced design intake 

velocity to ≤ 0.5 ft/sec 

No requirements relative to impingement mortality reduction. If 

subject to entrainment performance standard, the facility must only 

address entrainment in the applicable components of its 

Comprehensive Demonstration Study, based on the compliance 

option selected for entrainment reduction. 

2. Demonstrate that 

existing design and 

construction technologies, 

operational measures, 

and/or restoration 

measures meet the 

performance standards 

Proposal for Information Collection 

Source Waterbody Flow Information 

Impingement Mortality and/or Entrainment Characterization Study 

(as appropriate) 

Technology and Compliance Assessment Information 

• Design and Construction Technology Plan 

• Technology Installation and Operation Plan 

Restoration Plan (if appropriate) 

Verification Monitoring Plan 

3. Demonstrate that facility 

has selected design and 

construction technologies, 

operational measures, 

and/or restoration 

measures that will, in 

combination with any 

existing design and 

construction technologies, 

operational measures, 

and/or restoration 

measures, meet the 

performance standards. 

Proposal for Information Collection 

Source Waterbody Flow Information 

Impingement Mortality and/or Entrainment Characterization Study 

(as appropriate) 

Technology and Compliance Assessment Information 

• Design and Construction Technology Plan 

• Technology Installation and Operation Plan 

Restoration Plan (if appropriate) 

Verification Monitoring Plan 

4. Demonstrate that facility 

has installed and properly 

operates and maintains an 

approved technology 

Technology Installation and Operation Plan 

Verification Monitoring Plan 
A-17 

Table A-3 Continued 

5. demonstrate that a sitespecific determination of 

BTA is appropriate 

Proposal for Information Collection 

Source Waterbody Flow Information 

Impingement Mortality and/or Entrainment Characterization Study 

(as appropriate) 

Technology Installation and Operation Plan 

Restoration Plan (if appropriate) 

Information to Support Site Specific Determination of BTA 

including: 

• Comprehensive Cost Evaluation Study (Cost-Cost test and 

Cost-Benefit test); 

• Valuation of Monetized Benefits of Reducing IM&E (CostBenefit test only); 

• Site-Specific Technology Plan (Cost-Cost test and CostBenefit test); 

Verification Monitoring Plan 
A-18 

Figure A-1 Sample Compliance Timeline (Figure 1 – EPA 2004a) 
A-19 

References 

United States Environmental Protection Agency (EPA). 2004a. National Pollutant Discharge 

Elimination System - Final Regulations to Establish Requirements for Cooling Water Intake 

Structures at Phase II Existing Facilities. July 9, 2004 Federal Register: Vol. 69, No. 131 Pg 

41576-41693
B-1

APPENDIX B

OVERVIEW OF INTAKE TECHNOLOGIES AVAILABLE FOR FISH PROTECTION 

Overview of Intake Technologies 

Depending on their mode of action, available fish protection systems fall into one of four 

categories: behavioral barriers, which alter or take advantage of natural behavior patterns to 

attract or repel fish; physical barriers, which physically block fish passage; collection systems, 

which actively collect fish for their return to a safe release location; and diversion systems, 

which divert fish to bypasses for return to a safe release location. A review of the biological 

effectiveness, engineering practicability, and costs of these systems and devices is presented in 

detail in three Electric Power Research Institute (EPRI) reports prepared in 1986, 1994 and 1999 

(EPRI 1986, 1994b, 1999). The EPRI reports, along with results of recent research, provide the 

basis for screening alternatives for potential use at the Station, as presented in this appendix. 

Extensive research has been conducted since the early 1970s in an attempt to develop 

technologies that will minimize entrainment and impingement. As a result, a suite of 

technologies is available that can be considered for application as BTA at CWISs. The ability of 

a given technology to meet BTA requirements is influenced by a wide variety of biological, 

environmental and engineering factors that must be evaluated on a site-specific basis. 

Technology Category Mode of Action System/Technology 

Physical Barriers Physically block fish passage 

(usually in combination with 

low water velocity) 

Traveling screens 

Stationary screens 

Drum screens 

Cylindrical wedge wire screens

Barrier nets 

Aquatic filter barrier 

Rock Structures 

Infiltration Intakes 

Rotary drum screens 

Collection Systems Actively or passively collect 

fish for transport through a 

return system 

Modified traveling screens 

Fish pumps 

Diversion Systems Divert fish to a return system 

or safe area 

Angled screens 

Modular Inclined Screen 

Eicher Screen 

Angled rotary drum screens 

Louvers/Angled bar racks 

Inclined plane screens 

Vertical/Horizontal traveling 

screens 
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Technology Category Mode of Action System/Technology 

Behavioral Barriers Alter or take advantage of 

natural behavior patterns to 

repel or attract fish 

Strobe light 

Mercury light 

Other light sources 

Acoustic systems 

Infrasound 

Air bubble curtains 

Hybrid systems 

Velocity Caps 

Other behavioral technologies 

As support for the screening process and selection of alternatives for further evaluation, the 

following is a brief summary of the status of available fish protection technologies by category. 

PHYSICAL BARRIERS 

Traveling Screens (Through flow, Dual flow, Center flow, Drum, etc). The traveling water 

screen is a standard feature at most CWISs. The ability of traveling screens to act as a barrier to 

fish, while not resulting in impingement, is dependent on many site-specific factors such as size 

of fish, flow velocity, location of screens, and presence of escape routes. As barrier devices, 

traveling screens cannot be considered for protection of early life stages or aquatic organisms 

that have little or no motility. 

Cylindrical Wedge Wire Screens. Wedge wire screens have the potential to reduce both 

entrainment and impingement at water intakes. In order to effectively reduce impingement and 

entrainment, the following conditions must exist: 

• sufficiently small screen slot size to physically block passage of the smallest life stage to 

be protected (typically 0.5 to 1.0 mm for egg and larval life stages); 

• low through-slot velocity (on the order of 0.5 to 1.0 ft/s); and 

• an ambient current cross-flow to carry organisms and debris around and away from the 

screen); 

To date, large-scale CWIS applications of wedge wire screens have been limited to two plants 

(J.H. Campbell Unit 3 and Eddystone Station) where relatively large slot openings have been 

used (i.e., they have not been targeted specifically to prevent entrainment of early life stages). 

These screens have been biologically effective in preventing impingement of larger fish and have 

not caused any unusual maintenance problems. 

EPRI and the U. S. Environmental Protection Agency (EPA) sponsored laboratory evaluations of 

wedge wire screens with eggs and/or larvae of nine fish species commonly entrained at CWISs 

(EPRI 2003, in press). General entrainment and impingement trends observed in the data 
B-3

collected included: 1) impingement decreased with increases in slot size; 2) entrainment 

increased with increases in slot size; 3) entrainment and impingement increased with increases in 

through-slot velocities; 4) entrainment and impingement decreased with increases in channel 

velocity, and 5) within a species, larval fish length did not appear to be a factor, although the 

lengths of most species evaluated were within a narrow size range. 

Wedge wire screens can generally be considered for application at CWISs. Since the only two 

large CWISs to employ wedge wire screens to date use 6.4 and 10.0 mm slot openings, the 

potential for clogging and fouling with slot sizes as small as 0.5 to 1.0 mm (as would be required 

for protection of many entrainable life stages) is unknown. In general, consideration of wedge 

wire screens with small slot dimensions for CWIS application should include in situ prototype 

scale studies to determine potential biological effectiveness and identify the ability to control 

clogging and fouling in a way that does not impact station operation. 

Aquatic Filter Barrier (AFB). The aquatic filter barrier is a relatively recent technology for the 

protection of all life stages of fish at water intakes. As a result, there are limited data available 

on their deployment for this purpose. The AFB consists of polyester fiber strands that are 

pressed into a water-permeable fabric mat. Beginning in 1995, Mirant, New York, LLC. has 

sponsored an evaluation of the AFB to determine its ability to minimize ichthyoplankton 

entrainment at the Lovett Generating Station on the Hudson River (ASA 1999, 2001). Despite 

difficulties in keeping the boom deployed and providing adequate cleaning in 1995-1997, results 

of studies in 1998 show a large reduction in entrainment and it appears that deployment and 

cleaning problems may have been resolved for this site. Results analyzing the rate of 

ichthyoplankton entrainment between two side-by-side water intakes (one protected by an AFB 

and the other unprotected) have shown the potential biological effectiveness of this technology 

(ASA 1999; 2001). 

Laboratory studies on retention and survival of the early life stages of five species of fish 

exposed to aquatic filter barrier fabric were conducted in 2002 (Black et al., in press). Results of 

testing with three perforation sizes (0.5, 1.0, and 1.5 mm) and two flow rates (10 gpm/ft2

 and 20 

gpm/ft2

) indicate that, in general, survival of organisms was not significantly correlated to either 

flow rate or perforation size. Retention of organisms, however, appeared to decrease 

significantly with increasing flow rate for one species of fish (rainbow smelt). In addition, 

increasing perforation sizes appeared to significantly decrease retention of three species of fish 

tested (common carp, rainbow smelt, and striped bass), which potentially limits the effectiveness 

of larger perforation sizes in protecting the earliest life stages of these species. 

At this time, the AFB system is considered to be experimental despite its potential biological 

effectiveness. However, continued improvements in anchoring and cleaning systems make AFBs 

a technology to be considered when evaluating fish protection alternatives. 

Infiltration Intakes. Radial wells and artificial filter beds have been successfully used to supply 

small quantities of water. While such systems have little if any biological impact, they have not 

been developed for screening large flow volumes or for CWIS application. 
B-4

Rock Structures. Rock structures such as rock cribs and porous dikes allow water to pass while 

preventing passage of juvenile and adult fish. Such structures have been shown to be effective 

on an experimental basis. Rock structures have been used on a limited basis to filter large 

quantities of water but should be considered a potentially viable option for use at a CWIS 

depending upon the species and life stages to be protected and the presence of suitable hydraulic 

conditions. 

Barrier Nets. Under the proper hydraulic conditions (primarily low velocity) and without heavy 

debris loading, barrier nets have been effective in blocking fish passage into water intakes. 

There have been several recent applications of barrier nets in the Midwest (Michaud and Taft 

1999). At the Ludington Pumped Storage Plant on Lake Michigan, a 2.5-mile long barrier net, 

set in open water around the intake jetties, has been successful in reducing entrainment of all fish 

species occurring in the vicinity of the intake (Reider et al. 1997). The net was first deployed in 

1989. Modifications to the design in subsequent years have led to a net effectiveness for target 

species (five salmonid species, yellow perch, rainbow smelt, alewife and chub) of over 80% 

since 1991, with an overall effectiveness of 96% in 1995 and 1996. 

In 1993 and 1994, Orange and Rockland Utilities, Inc. sponsored a study of a 3.0-mm, fine mesh 

net at its Bowline Point Generating Station on the Hudson River (LMS 1996). In 1993, clogging 

with fine suspended silt caused the net to clog and sink. In 1994, spraying was not effective in 

cleaning the net when it became fouled by the algae Ectocarpus. Excessive fouling caused two 

of the support piles to snap, ending the evaluation (LMS 1996). In both years, abundance of the 

target ichthyoplankton species, bay anchovy, was too low to determine the biological 

effectiveness of the net. On the basis of studies to date, the researchers concluded that a fine 

mesh net may be a potentially effective method for preventing entrainment at Bowline Point 

(LMS 1996). However, pending further evaluation, this concept is considered to be 

experimental. 

In conclusion, barrier nets can be considered a viable option for protecting fish provided that 

relatively low velocities (generally less than 1 ft/sec) can be achieved and debris loading is light. 

A thorough evaluation of site-specific environmental and operational conditions is generally 

recommended. At this time, barrier nets can only be considered for reducing impingement of 

larger fish at CWIS. 

FISH COLLECTION SYSTEMS 

Modified Traveling Water Screens. Conventional traveling water screens have been altered to 

incorporate modifications that improve survival of impinged fish. Such state-of-the-art 

modifications minimize fish mortality associated with screen impingement and spraywash 

removal. Screens modified in this manner are commonly called “Ristroph screens.” Each screen 

basket is equipped with a water filled lifting bucket that safely contains collected organisms as 

they are carried upward with the rotation of the screen. The screens typically operate 

continuously to minimize impingement time. As each bucket passes over the top of the screen, 

fish are rinsed into a collection trough by a low pressure spraywash system. Once collected, the 
B-5

fish are transported back to a safe release location. Such features have been incorporated into 

through flow, dual flow, and center flow screens. 

Ristroph screens have been shown to improve fish survival and have been installed and evaluated 

at a number of power plants. Improvements have recently been made to the Ristroph screen 

design that have resulted in increased fish survival. The most important advancement in state-ofthe-art Ristroph screen design was developed through extensive laboratory and field 

experimentation. A series of studies conducted by Fletcher (1990) indicated that substantial 

injury associated with these traveling screens was due to repeated buffeting of fish inside the 

lifting buckets as a result of undesirable hydraulic conditions. To eliminate these conditions, a 

number of alternative bucket configurations were developed to create a sheltered area in which 

fish could safely reside during screen rotation. After several attempts, a bucket configuration 

was developed that achieved the desired conditions (ENVIREX 1996). In 1995, PSE&G 

performed a biological evaluation of the improved screening system installed at the Salem 

Generating Station in the Delaware River (PSE&G 1999; Ronafalvy 1999). The reported 

survival rates for this installation are among the highest for any traveling screen system. 

(PSE&G 1999). 

Modified traveling water screens continue to be an available technology that can reduce fish 

losses due to impingement. Unless modified to incorporate fine mesh, as discussed below, these 

screens do not reduce entrainment losses. 

Fine-mesh Traveling Screens. In addition to the fish handling provisions noted above, traveling 

water screens have been further modified to incorporate screen mesh with openings as small as 

0.5 mm to collect fish eggs and larvae and return them to the source water body. For many 

species and early life stages, mesh sizes of 0.5 to 1.0 mm are required for effective screening. 

Various types of traveling screens, such as through flow, dual flow, and center flow screens, can 

be fitted with fine mesh screen material. 

A number of fine mesh screen installations have been evaluated for biological effectiveness. 

Results of these studies indicate that survival is highly species-specific and life stage-specific. 

Species such as bay anchovy and Alosa spp. have shown low survival while other species, such 

as striped bass, white perch, yellow perch, and invertebrates, show moderate to high survival. 

Therefore, evaluating fine mesh screens for potential application at a CWIS requires careful 

review of all available data on the survival potential of the species and life stages to be protected 

as well as non-target species. 

In addition to these field applications, survival data on a variety of species and life stages 

following impingement on fine-mesh screens is available from extensive laboratory studies 

(ESSERCO 1981). In these studies, larval life stages of striped bass, winter flounder, alewife, 

yellow perch, walleye, channel catfish, and bluegill were impinged on a 0.5 mm screen mesh at 

velocities ranging from 0.5 to 3.0 ft/sec and for durations of 2, 4, 8 or 16 minutes. As in the field 

evaluations, survival was variable between species, larval stages, impingement duration, and 

velocity. 
B-6

The primary concern with fine mesh screens is that they function by impinging early organism 

life stages that are entrained through coarse mesh screens. Depending on species and life stage, 

mortality from impingement can exceed entrainment mortality. In order for fine mesh screens to 

provide a meaningful benefit in protecting fish, impingement survival of target species and life 

stages must be substantially greater than survival levels when pulled through the circulating 

water system. 

Fish Pumps. Several pumps have demonstrated an ability to transfer fish with little or no 

mortality. These include the Hidrostal and Archimedes screw pumps that have undergone 

extensive research (Liston et al. 1993). These pumps by themselves do not represent a 

technology for protecting fish. However, when coupled with fish bypass systems such as angled 

screens and louvers, fish pumps are biologically effective. 

FISH DIVERSION SYSTEMS 

Angled Screens. A variety of species have been shown to guide effectively on screens given 

suitable hydraulic conditions. Angled screens require uniform flow conditions, a fairly constant 

approach velocity, and a low through-screen velocity to be biologically effective. Angled screen 

systems have been installed and biologically evaluated at a number of cooling water intakes on a 

prototype and full scale basis. Angled screen diversion efficiency varies by species, but is 

generally quite high for most species evaluated. Survival following diversion and pumping (as 

required to return fish to their natural environment) has been more variable. Overall survival 

rates of relatively fragile species following diversion can be low. Heartier species exhibit higher 

survival rates resulting in overall system efficiency values (diversion and survival) ranging from 

50 to nearly 100%. 

In addition to the CWIS applications, angled fish diversion screens leading to bypass and return 

pipelines are being used extensively for guiding salmonids in the Pacific Northwest. These 

screens are mostly of the rotary drum or vertical, flat panel (non-moving) types and have 

provided effective downstream protection for juvenile salmonids at several diversion projects in 

the Pacific Northwest(Neitzel et al. 1991; EPRI 1998). Like other angled screens, suitable 

hydraulic conditions at the screen face and a safe bypass system are required for the screens to 

effectively protect fish from entrainment and impingement and to divert them to a bypass for 

return to the source water body (Pearce and Lee 1991). 

Angled screens can be considered a viable option for protecting juvenile and adult life stages 

provided that proper hydraulic conditions can be maintained and debris can be effectively 

removed. To date, all angled screen applications at cooling water intakes have involved the use 

of conventional traveling water screens modified to provide a flush surface on which fish can 

guide to a bypass. Fish eggs, larvae, and small invertebrates would not be protected by angled 

screens unless fine mesh screening was used. 

Eicher Screen. The Eicher screen is a passive pressure screen that has proven effective in 

diverting salmon at hydroelectric projects. The first prototype of an Eicher Screen was 
B-7

constructed and installed in a 9-ft diameter penstock at a hydroelectric project in the Pacific 

Northwest. Field testing of the screen conducted in 1990 and 1991 demonstrated that the Eicher 

screen effectively diverted over 98% of the steelhead, coho, and chinook smolts (EPRI 1992). 

The first full-scale Eicher screen installation (two screens in two, 10-ft diameter penstocks; total 

flow of 1,000 cfs) at B. C. Hydro's Puntledge Project has shown similar results. Survival of 

chinook and coho salmon smolts exceeded 99%, and survival of steelhead, sockeye, and chum 

salmon fry was 100%, 96%, and 96%, respectively, at penstock velocities up to 6 ft/sec (Smith 

1997). While biologically effective, the Eicher Screen was not designed for use at steam electric 

station cooling water intakes. 

Modular Inclined Screens. The Modular Inclined Screen (MIS) has recently been developed and 

tested by the Electric Power Research Institute (EPRI 1994a; EPRI 1996; Taft et al. 1997). The 

MIS is intended to protect juvenile and adult life stages of fish at all types of water intakes. An 

MIS module consists of an entrance with trash racks, dewatering stoplogs in slots, an inclined 

screen set at a shallow angle (10 to 20 degrees) to the flow, and a bypass for directing diverted 

fish to a transport pipe. The module is completely enclosed and is designed to operate at 

relatively high water velocities ranging from 2 to 10 ft/sec, depending on the species and life 

stages to be protected. 

The MIS was evaluated in laboratory studies to determine the design configuration which 

yielded the best hydraulic conditions for safe fish passage, and the biological effectiveness of the 

optimal design in diverting selected fish species to a bypass (EPRI 1994a). Biological tests were 

conducted in a large flume with juvenile walleye, bluegill, channel catfish, American shad, 

blueback herring, golden shiner, rainbow trout (two size classes), brown trout, chinook salmon, 

coho salmon, and Atlantic salmon. Screen effectiveness (diversion efficiency and latent 

mortality) was evaluated at water velocities ranging from 2 ft/sec to 10 ft/sec. Diversion rates 

approached 100% for all species except American shad and blueback herring at water velocities 

up to at least 6 ft/sec. Generally, latent mortality of test fish that was adjusted for control 

mortality was low (0 to 5%). 

Based on the laboratory results, a pilot scale evaluation of the MIS was conducted at Niagara 

Mohawk Power Corporation’s Green Island Hydroelectric Project on the Hudson River near 

Albany, NY (EPRI 1996). The results obtained in this field evaluation with rainbow trout, 

largemouth and smallmouth bass, yellow perch, bluegill, and golden shiners were similar to 

those obtained in laboratory studies (Taft et al. 1997).

The combined results of laboratory and field evaluations of the MIS have demonstrated that this 

screen is an effective fish diversion device that has the potential for protecting fish at water 

intakes. Studies to date have only evaluated possible application at hydroelectric projects. 

Further, no full-scale MIS facility has been constructed and evaluated. As a result, the potential 

for effective use at cooling water intakes is unknown. Any consideration of the MIS for CWIS 

application should be based on future large-scale, prototype evaluations. 

Louvers. A louver system consists of an array of evenly spaced, vertical slats aligned across a 

channel at a specified angle and leading to a bypass. Bar racks can also be angled to act as 

louvers. Results of louver studies to date have varied by species and site. Most of the louver 
B-8

installations in the U.S. are in the Pacific Northwest at water supply intakes. Louvers generally 

are not considered acceptable by the fishery resource agencies in that region since they do not 

meet the current 100% effectiveness criterion. However, numerous studies have demonstrated 

that louvers can be on the order of 70 to 95% effective in diverting a wide variety of species over 

a wide range of conditions (EPRI 1986; Stira and Robinson 1997; LMS 1997). 

Until recently, the effectiveness of diversion devices for non-anadromous fish has been largely 

unknown. Recent studies by the Electric Power Research Institute (EPRI) evaluated the potential 

for 15 and 45 degree louvers for guiding riverine species (smallmouth bass, largemouth bass, 

walleye, channel catfish, and golden shiner) and others (lake sturgeon, shortnose sturgeon, and 

American eel) (EPRI 2001, Amaral et al., 2002). Results indicate that 15-degree structures have 

considerable potential for guiding fish to a bypass. 

Most of the louver applications to date have been with migratory species in riverine 

environments. The ability of louvers to protect species commonly impinged at CWISs is largely 

unknown because there have been so few louvers installed at CWISs. A system of guiding vanes 

and louvers has been installed at San Onofre Nuclear Generating Station (EPRI 1986) to direct 

fish away from the traveling screens into a collection area. Biological effectiveness of these 

louvers is unknown. 

Due to the large spacing of the louver slats, louver systems do not protect early life stages of fish. 

Future consideration of louver systems for protecting fish at cooling water intakes is warranted 

but will require large-scale evaluations. 

BEHAVIORAL BARRIERS 

Strobe Lights. 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 light. Strobe has been evaluated for repelling or guiding fish away from water 

intakes and, in some cases, towards bypasses for transport to a safe release location (EPRI 

1994b, 1999). Early studies with light examined the response of salmonids to both flashing and 

continuous sources (Brett and MacKinnon 1953; Craddock 1956). The results from these studies 

indicated that flashing light produced stronger avoidance reactions than continuous light and that 

responses appeared to be affected by species tested, developmental stage (i.e., age or size of 

fish), and light adaptation level (Feist and Anderson 1991). More recent studies with salmonids 

have corroborated these findings (Puckett and Anderson 1987; EPRI 1990; Nemeth and 

Anderson 1992). 

Research examining the potential for strobe light to be used as a fish deterrent expanded 

considerably in the 1980s, including laboratory studies with anadromous salmonids and Alosa 

species, several riverine and estuarine species, and the catadromous American eel. These studies 

involved both controlled experiments (laboratory and cage tests) and field studies. Extensive 

research with strobe lights has continued in the 1990s, including laboratory and/or cage test 
B-9

evaluations with Pacific salmon, American eel, and several freshwater species, open water tests 

with kokanee salmon, and field tests with freshwater species and Atlantic salmon. 

Although many studies have evaluated strobe lights as a primary barrier system, strobes are often 

evaluated as part of an integrated fish protection and passage system that includes other devices 

such as screens, narrow-spaced bar racks, bypasses, and/or other behavioral systems (EPRI 

1994b, 1999). As a secondary system, strobe lights have the potential to incrementally increase 

fish protection effectiveness. 

Air Bubble Curtains. These curtains generally have been ineffective in blocking or diverting 

fish in a variety of field applications. Air bubble curtains have been evaluated at number of sites 

on the Great Lakes with a variety of species. All air bubble curtains at these sites have been 

removed from service.

Sound. The focus of recent fish protection studies involving underwater sound technologies has 

been on the use of new types of low and high frequency acoustic systems that have not 

previously been available for commercial use. High frequency (120kHz) sound has shown to 

effectively and repeatedly repel members of the Genus Alosa (American shad, alewife and 

blueback herring) at sites throughout the U. S. (Ploskey et al. 1995; Dunning 1995; Consolidated 

Edison 1994). Other studies have not shown sound to be consistently effective in repelling 

species such as largemouth bass, smallmouth bass, yellow perch, walleye, rainbow trout (EPRI 

1998), gizzard shad, Atlantic herring, and bay anchovy (Consolidated Edison 1994). 

Given the species-specific responses to different frequencies that have been evaluated and the 

variable results that often have been produced, additional research is warranted at any sites 

where there is little or no data to indicate that the species of concern may respond to sound. 

Infrasound. In the first practical application of infrasound (frequencies below 100 Hz) for 

repelling fish, Knudsen and colleagues (Knudsen et al. 1992; 1994) found a piston-type particle 

motion generator operating at 10 Hz to be effective in repelling Atlantic salmon smolts in a tank 

and in a small diversion channel. Following this success, there was a general belief in the 

scientific community that infrasound could represent an effective fish repellent since there was a 

physiological basis for understanding the response of fish to particle motion. The potential for 

currently available infrasound sources to effectively repel fish has been brought into question by 

the results of more recent studies (e.g., Amaral et al. 1998; Lakeside Engineering, 1996). Given 

these results, it appears that infrasound sources need to be further developed and evaluated 

before they can be considered an available technology for application at CWISs. 

Mercury Light. Response to mercury light has been shown to be species-specific; some fish 

species are attracted, others repelled, and others have demonstrated no obvious response (e.g., 

GNPC 1995, 1998; Hadderingh and Smythe 1997; EPRI 1990). Therefore, careful consideration 

must be given for any application of mercury lights to avoid increasing impingement of some 

species while reducing impingement of others. 

Electric Screens. Electric barriers have been shown to effectively prevent the upstream passage 

of fish. However, attempts to divert or deter the downstream movement of fish have met with 
B-10

limited success (Bengeyfield 1990; Kynard and O’Leary 1990). Consequently, past evaluations 

have not lead to permanent applications. Electric screens that use DC current have been used to 

prevent passage of fish at relatively low flow intakes (e.g. irrigation canals) and to prevent 

upstream passage of invasive fish species. The potential effectiveness of these barriers for 

application at CWISs is unknown. Given their past ineffectiveness and hazard potential, electric 

screens are not considered a viable technology for application at CWISs. 

Velocity Caps. Velocity caps are a common feature at many submerged intakes. They offer 

some degree of protection to juvenile and adult fish by acting as a behavioral barrier. While 

there is little available data to quantify the effect that velocity caps have on fish behavior, it is 

generally believed that a cap on a submerged intake provides horizontal velocity cues to 

approaching fish. In some instances, reported reductions in entrainment and impingement 

associated with velocity caps have been the result of the location of the intake in deeper, less 

productive zones. 

Other behavioral barriers. Devices such as water jet curtains, hanging chains, visual cues, and 

chemicals have been suggested, and in some cases evaluated, as fish protection measures. 

However, no practical application of these devices has been developed, and they are not 

considered available technologies for application at CWISs. 
B-11

References 

Applied Science Associates Analysis & Communication, Inc. (ASA). 2001. Ichthyoplankton 

Monitoring Study, Deployment of the Gunderboom MLESTM at Lovett Generating Station Unit 

3, 2000, Final Report. 

ASA. 1999. Ichthyoplankton Monitoring Study: Development of a Gunderboom System at 

Lovett Generating Station Unit 3 1998 Final Report. 

Amaral, S. V., F. C. Winchell, B. J. McMahon and E. P. Taft. 1998. Evaluation of Behavioral 

Guidance Technologies for Diverting Chinook Salmon Smolts at the Roza Dam Screening 

Facility. Prepared for the Yakima/Klictikat Fisheries Project. 

Amaral, S. V., J. L. Black, B. J. McMahon, and D. A. Dixon. 2002. Evaluation of Angled Bar 

Racks and Louvers for Guiding Lake and Shortnose Sturgeon. American Fisheries Society 

Symposium 28: 197-210 

Black, J.L., T. W. Hogan, G. S. Allen, E. S. Perry, and K. D. Zammit. In press. Laboratory 

Evaluation of an Aquatic Filter Barrier (AFB) for Protecting Early Life Stages of Fish. 

American Fisheries Society Bioengineering Symposium 4. Bethesda, MD. 

Brett, J. R. and D. McKinnon. 1953. Preliminary Experiments Using Lights and Bubbles to 

Deflect Migrating Young Spring Salmon. J. Fish. Res. Bd. Canada 10(8): 548-556. 

Beak Consultants, Inc. 1988. Dunkirk Steam Station Biological Studies – SPDES Permit No. 

NY0002321; Final Report January-December 1987. Prepared for Niagara Mohawk Power 

Corporation. 

Bengeyfield, W. 1990. Evaluation of an Electrical Field to Divert Coho Salmon Smolts from 

the Penstock Intake at Puntledge Generating Station. Prepared by Global Fisheries Consultants 

Ltd for B.C. Hydro, Vancouver, B.C. 

Consolidated Edison Company of New York, Inc. 1994. Evaluation of Underwater Sound to 

Reduce Impingement at the Arthur Kill Station. 

Craddock, D. R. 1956. A review of Studies in Guiding Downstream Migrating Salmon with 

Light. In: Progress Report on Fisheries Engineering Research Program. U. S. Army, North 

Pacific Division, Corps of Engineers, Portland, Oregon, pg. 1-13.

Dunning, D. 1995. Ultrasound Deterrence: Alewife at a Nuclear Generating Station in New 

York. In T. J. Carlson and A. N. Popper (eds.): Using Sound to Modify Fish Behavior at PowerProduction and Water-Control Facilities: A Workshop. Prepared for U.S. Department of Energy 

and Bonneville Power Administration, DOE/BP-62611-11. 
B-12

Electric Power Research Institute (EPRI). 1986. Assessment of Downstream Migrant Fish 

Protection Technologies for Hydroelectric Application. 2694-1. 

EPRI. 1990. Fish Protection Systems for Hydro Plants; Test Results. EPRI GS-6712. 

EPRI. 1992. Evaluation of the Eicher Screen at Elwha Dam: 1990 and 1991 Test Results. TR101704. 

EPRI. 1994a. Biological Evaluation of a Modular Inclined Screen for Protecting Fish at Water 

Intakes. TR-104121. 

EPRI. 1994b. Research Update on Fish Protection Technologies for Water Intakes. TR104122. 

EPRI. 1996. Evaluation of the Modular Inclined Screen (MIS) at the Green Island 

Hydroelectric Project: 1995 Test Results. TR-106498. 

EPRI. 1998. Evaluation of Fish Behavioral Barriers. TR-109483. 

EPRI. 1999. Fish Protection at Cooling Water Intakes. TR-114013 

EPRI 2001. Evaluation of Angled Racks and Louvers for Guiding Fish at Water Intakes. 

1005193 

EPRI 2003. In press. Evaluation of Wedge Wire Screens for Protecting Early Life Stages of 

Fish at Cooling Water Intakes. 

Empire State Electric Energy Research Corporation (ESEERCO). 1981. Laboratory Evaluation 

of Fine-mesh Screening for the Protection of Fish Larvae at Intakes. Empire State Electric 

Energy Research Corporation Research Report EP 8-6, Final Report. 

Envirex, Inc. 1996. Fish Survival Enhancement with Envirex Non-Metallic Fish Baskets and 

Improved Fish Spray Wash Design. Envirex, Inc., Waukesha, WI. 

Feist, B. A., and J. J. Anderson. 1991. Review of Fish Behavior Relevant to Fish Guidance 

Systems. Fisheries Research Institute, FRI-UW-9102. University of Washington, Seattle WA. 

Fletcher, R. I. 1990. Flow Dynamics and Fish Recovery Experiments: Water Intake Systems. 

Transactions of the American Fisheries Society. 119:393-415. 

Great Northern Paper Company. 1995. The Effectiveness of Permanent Downstream Passage 

Facilities for Atlantic Salmon at Weldon Dam. Mattaceunk Project, FERC No. 2520. 

Great Northern Paper Company. 1998. Report on Downstream Fish Passage Studies 

Mattaceunk Hydroelectric Project. Great Northern Paper Company. 
B-13

Hadderingh, R. H. and A. G. Smythe. 1997. Deflecting Eels from Power Stations with Light. 

In: Fish Passage Workshop, Milwaukee, WI, May 6–8, 1997. Sponsored by Alden Research 

Laboratory, Conte Anadromous Fish Research Laboratory, Electric Power Research Institute, 

and Wisconsin Electric Power Company. 

Knudsen, F. R., P. S. Enger, and O. Sand. 1992. Awareness Reactions and Avoidance 

Responses to Sound in Juvenile Atlantic Salmon, Salmo salar L. Journal of Fish Biology 

40:523-534. 

Knudsen, F. R., P. S. Enger, and O. Sand. 1994. Avoidance Responses to Low Frequency 

Sound in Downstream Migrating Atlantic Salmon, Salmo salar L. Journal of Fish Biology 

45:227-233. 

Lakeside Engineering, Inc. 1996. Summary Report for Rolfe Canal Project. Essex Hydro. 

Kynard, B. and J. O'Leary. 1990. Behavioral Guidance of Adult American Shad Using 

Underwater AC Electrical and Acoustic Fields. Proceedings of the International Symposium on 

Fishways '90. October 8-10, 1990, Gifu, Japan, pp. 131-135. 

Lawler, Matusky & Skelly Engineers (LMS). 1992. Intake Technology Review Oswego Steam 

Station Units 1-6. Prepared for Niagara Mohawk Power Corporation. 

Lawler, Matusky & Skelly Engineers (LMS). 1996. Effectiveness Evaluation of a Fine Mesh 

Barrier Net Located at the Cooling Water Intake of the Bowline Point Generating Station. 

Prepared for Orange and Rockland Utilities, Inc. 

Lawler, Matusky & Skelly Engineers (LMS). 1997. Lovett Generating Station Gunderboom 

System Evaluation Program 1996. Prepared for Orange and Rockland Utilities, Inc. 

Liston, C. R.; R. Brockman, G. Sackett, C. Karp, L. Hess, P. Johnson, S. Hiebert, and G. 

Mueller. 1993. Improvements in fish collection facilities at the Federal Tracy pumping plant in 

the south San Fransisco Bay Delta, California. Proceedings of the American Fisheries Society 

Fish Passage Symposium. Portland, Oregon, September 1993 pp 155-160. 

Michaud, D. T. and E. P. Taft. 1999. Recent Evaluation of Physical and Behavioral Barriers for 

reducing Fish Entrainment at Hydroelectric Projects in the Upper Midwest,” Proceedings of the 

EPRI/DOE Power Generation Impacts on Aquatic Resources Conference, Atlanta, GA (April 

1999). 

Neitzel, D. A., C. S. Abernethy, and E. W. Lusty. 1991. Evaluating of Rotating Drum Screen 

Facilities in the Yakima River Basin, South-Central Washington State.” In: Fisheries 

Bioengineering Symposium. American Fisheries Society Symposium 10: 325-334. 

Nemeth, R. S. and J. J. Anderson. 1992. Response of Juvenile Coho and Chinook Salmon to 

Strobe and Mercury Vapor Lights. North American Journal of Fisheries Management. Vol. 12: 

684-692. 
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Pearce, R. O. and R. T. Lee. 1991. Some Design Considerations for Approach Velocities at 

Juvenile Salmonid Screening Facilities. In: Fisheries Bioengineering Symposium. American 

Fisheries Society 10:237-248. 

Ploskey, G. R., J. M. Nestler, G. N. Weeks, and C. Schilt. 1995. Evaluation of an Integrated 

Fish-Protection System. Waterpower 95, Proceedings of the International Conference on 

Waterpower. American Society of Civil Engineers, New York, NY. 

Public Service Gas and Electric (PSE&G). 1999. Biological Efficacy of Intake Structure 

Modifications. PSE&G Renewal Application Salem Generating Station. Permit No. NJ0005622. 

Puckett, K.J., and J.J. Anderson. 1987. Behavioral Responses of Juvenile Salmonids to Strobe 

and Mercury Lights. Fisheries Research Institute, University of Washington. FRI-UW-8717. 

Reider, R. H., D. D. Johnson, P. Brad Latvaitis, J. A. Gulvas, E. R. Guilfoos. 1997. Operation 

and Maintenance of the Ludington Pumped Storage Project Barrier Net.” Proceedings of Fish 

Passage Workshop, Milwaukee, Wisconsin, May 6-8, 1997. Sponsored by Alden Research 

Laboratory, Conte Anadromous Fish Research Laboratory, Electric Power Research Institute, 

and Wisconsin Electric Power Company. 

Ronafalvy, J. P. 1999. Circulating Water Traveling Screen Modifications to Improve Impinged 

Fish Survival and Debris Handling at Salem Generating Station. Proceedings of the EPRI/DOE 

Power Generation Impacts on Aquatic Resources Conference, Atlanta, GA. 

Smith, H. 1997. Operating History of the Puntledge River Eicher Screen Facility. Proceedings 

of Fish Passage Workshop, Milwaukee, Wisconsin, May 6-8, 1997. Sponsored by Alden 

Research Laboratory, Conte Anadromous Fish Research Laboratory, Electric Power Research 

Institute, and Wisconsin Electric Power Company. 

Stira, R. J. and D. A. Robinson. 1997. “Effectiveness of a Louver Bypass System for 

Downstream Passage of Atlantic Salmon smolts and Juvenile Clupeids in the Holyoke Canal, 

Connecticut River, Holyoke, Massachusetts.” Proceedings of Fish Passage Workshop, 

Milwaukee, Wisconsin, May 6-8, 1997. Sponsored by Alden Research Laboratory, Conte 

Anadromous Fish Research Laboratory, Electric Power Research Institute, and Wisconsin 

Electric Power Company (1997). 

Taft, E. P., A. W. Plizga, E. M. Paolini, and C. W. Sullivan. 1997. Protecting Fish with the New 

Modular Inclined Screen. The Environmental Professional 19(1):185-191. 
C-1

APPENDIX C 

OVERVIEW OF REDUCED FLOW OPTIONS FOR FISH PROTECTION 

Reducing flow into power plant intakes can reduce fish entrainment. Flow can be reduced by: 1) 

modifying existing pump operations by reducing the number of operating pumps or throttling 

valves, 2) installing variable speed drives on the circulation water pumps, or by 3) retrofitting the 

plant with a closed-cycle cooling system. Reduction in entrainment for all three options would 

be roughly proportional to the flow reduction. Operating fewer pumps or installing variable 

speed motors on the existing circulating water pumps would allow operation at reduced flow 

rates during periods of high entrainment. A lower pump capacity would reduce the screen 

approach velocity, thereby potentially reducing impingement as well as entrainment. Make-up 

water for closed loop cooling systems can be as little as 2% of the flow into a once-through 

cooling system, thereby greatly reducing entrainment potential. However, the reduced effects of 

closed-cycle cooling systems on the aquatic environment resulting from small makeup water 

requirements can be countered by major airborne impacts such as noise impacts, aesthetic 

impacts, icing of roads and streets, reduced visibility from the tower vapor plume, and drift 

dispersion. 

Modified pump operation options and closed-loop cooling water alternatives that are available to 

reduce intake flow and fish entrainment are discussed in the following sections. 

MODIFIED PUMP OPERATION 

Reducing circulating water could be accomplished by reducing the number of operating pumps 

or by reducing the flow from each pump. If multiple circulating water pumps discharge into a 

common pipe to convey water to the plant condensers, operating fewer pumps would be possible. 

If pumps can not be shut off because of the piping configuration, throttling of discharge valves or 

variable speed drivers (power frequency or eddy current couplings) could be used to reduce flow. 

In any case, reduced flow would result in higher discharge water temperatures for the same heat 

transfer and, in some cases, plant output might have to be limited to meet permit requirements 

for thermal discharges. 

Estimates of the amount of flow reduction that is acceptable for satisfactory condenser 

performance are needed to evaluate modified pump operation alternatives. Pump performance 

characteristics must be reviewed to define operating limits if discharge valves are used to reduce 

flow. Throttling valves could require more power to operate the pump with less flow. Hydraulic 

grade lines must be developed to determine if negative pressures at the condenser outlet water 

boxes will be a problem. Installation or modifications of vacuum priming systems may be 

necessary to assure that the structural integrity and performance of the condenser is maintained. 

Important considerations that have to be addressed relative to backfitting motors with variable 

speed drivers are: 
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• Eddy current couplings are large and the size increases with lower speed requirements. 

Large eddy current couplings that would be necessary for large circulation water pumps 

are as big as the pump motors. 

• Voltage spikes from a variable frequency drive (VFD) can cause damage to the motor 

insulation. A reactor on the incoming line or between the VFD and the motor may be 

necessary to prevent damage to the insulation. 

• At slower speeds, existing motor cooling fans may not be able to remove the heat. 

Additional fans may be needed to cool the motor and prevent damage to the motor 

insulation. 

• Harmonics from a VFD may backfeed into the incoming power line affecting other 

power users. This problem has been eliminated with the newer VFD designs. 

All of the above issues should be discussed with the existing pump and motor manufacturers and 

variable speed drive suppliers to fully evaluate reduced flow alternatives. 

CLOSED-CYCLE COOLING SYSTEMS 

Cooling towers and cooling reservoirs are the primary closed-cycle cooling systems that are 

employed at power plants. Cooling reservoirs generally have very large surface areas, on the 

order of 4,000 to 10,000 acres, depending on the plant design. Cooling towers require less area 

than reservoirs, and for the purpose of this study, cooling towers are considered to be better 

suited for potential retrofit at existing plants than cooling reservoirs. Therefore, cooling 

reservoirs have not been included in this evaluation as a potential alternative to reduce fish 

entrainment. 

Wet and dry cooling towers are the two types of cooling towers that are typically used. Wet 

towers are the most common and reduce cooling water temperatures by direct contact with large 

volumes of air. Wet towers are classified as natural or mechanical draft, depending on how the 

airflow is induced through the tower. Cooling water in dry towers does not come in direct 

contact with air. Where plumes from towers are a concern, hybrid wet-dry towers can be used 

(EPA 2002). Wet-dry towers combine dry heat exchange surfaces with conventional wet cooling 

towers. 

Retrofitting any closed-cycle cooling system to an existing power plant is a difficult engineering, 

scheduling, and construction effort because most plants are not originally designed to 

accommodate unusual modifications (Burns et al, 1994b). The complexity and high costs 

associated with retrofitting a cooling tower to an existing plant are due to: 

• Permanence of existing site features and structures. 

• Fundamental design differences between once-through cooling systems and any 

alternative closed-cycle cooling technologies. 

• New construction must accommodate existing plant operational requirements and 

regulatory restrictions. 

• Installation of the tower facilities and long, underground, large diameter piping runs to 

and from the towers are difficult without contacting buried obstructions or contaminated 

soils. 
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Each of the retrofitted closed-cycle cooling systems, if installed, would reduce net generation 

because of design differences between closed- loop and once-through cooling systems. Reasons 

why retrofit of closed-cycle cooling at once-through plants cause reduced generation include 

(Parsons 2002): 

1. Turbine exhaust pressures are higher with a closed-loop cooling system than with a oncethrough system because of the seasonally higher water temperatures that the closed-loop 

system delivers to the condenser inlet. Higher turbine back pressure penalizes the unit 

heat rate and reduces power output. 

2. Cooling water has to be pumped to and up into cooling towers, requiring significantly 

more power than a once-through system. 

3. Except in the case of the natural draft tower, major amounts of energy are consumed in 

conveying the necessary fresh air through closed-cycle cooling equipment with the fans. 

4. Water flow through the condensers designed for once-though cooling must be 

appreciably reduced for closed-loop cooling to utilize cooling towers that are of a costeffective size. In the case of a natural draft towers, reduced flow is sometimes necessary 

to develop suitable draft. To be compatible with the required heat transfer conditions in a 

condenser with lower cooling water flow than the once-through design, the turbine 

backpressure must correspondingly rise which further reduces the plant output. 

Mechanical draft and natural draft cooling towers both have visible plumes that can cause 

concern. During periods of cooler weather, high relative humidity, and low winds, a visible 

plume out of the top of the towers is evident because the exit air temperature is higher than the 

ambient air temperature and is essentially at 100% relative humidity. As the air cools down to 

ambient conditions, the water vapor in the air becomes visible. 

A brief description of natural draft and mechanical draft wet cooling towers, dry cooling towers, 

hybrid wet-dry towers, and design considerations are presented below. 

Natural Draft Cooling Tower. A natural draft cooling tower transfers heat in the condenser 

closed-loop cooling water to ambient air that is induced to flow through the tower by the 

chimney effect (i.e., the density difference between the exhaust air inside the shell and the 

ambient air density surrounding the shell). Warm water from the condenser is distributed 

uniformly to the top of the fill section, which is located near the base of the tower. The fill 

section disperses the water into small droplets and thin sheets as it falls by gravity through the 

fill into the basin. The cooling effect provided in the fill section is mostly by the evaporation of 

a small percentage of the heated discharge water as it contacts the cooling air (Brocard and 

Burns, 1985). The remaining cooled water is recycled back through the condenser. The cooling 

(heat transfer) section of the natural draft tower is the fill which is typically an anti-fouling, nonclogging, plastic PVC material. 

Important environmental considerations associated with natural draft cooling towers are effects 

on air quality, ambient noise, and aesthetics. Natural draft cooling towers are large and, because 

of their size, the towers and their plumes have a major visual and aesthetic impact on the 

surrounding area. Natural draft towers overshadow all the surrounding structures and are visible 

from several miles away. The vapor plumes can also be considered obtrusive because during 
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ambient conditions that are stable, cold, and humid with little wind, the plumes extend far from 

the plant and with a variable trajectory. Because of the height of the towers, ground fog does not 

occur with natural draft towers. The falling water in a natural draft cooling tower creates sound 

levels that are typically less than 45 A-weighted decibels (dba) within 3,000 ft of the base of the 

tower. Noise attenuation measures can be incorporated into a natural draft tower design, but 

these measures could increase the tower costs by up to 15% (EPA 2002) 

Natural draft cooling towers typically concentrate the chemical and minerals in the makeup 

water drawn from the water body about five times. Concentration of the water is an inherent, 

natural consequence of the evaporation process for all types of wet cooling towers 

Mechanical Draft Cooling Towers. In a mechanical draft wet cooling tower, heat in the 

discharged warm condenser water is transferred to ambient air that is induced to flow through the 

tower by large, slow speed fans. The warm water is distributed uniformly to the top of the fill 

section of each cell of the tower and is dispersed into small droplets and thin sheets as it falls by 

gravity through the fill into the basin. The cooling effect provided in the fill section is mostly by 

the evaporation, similar to the natural draft cooling tower. The fill section is similar to natural 

draft towers and consists of anti-fouling, non-clogging, plastic PVC material. 

Environmental considerations associated with mechanical draft cooling towers are similar to the 

considerations for natural draft cooling towers. An opaque plume can be expected to occur and 

can extend downwind 500 to 1000 feet from the cooling tower, especially during the colder 

seasons. This may lead to icing of the roads under certain conditions. Drift dispersion from a 

mechanical draft tower is very local because the exhaust is close to the ground. Modern drift 

eliminator designs can limit drift to less than 6 gpm during normal operation. The usual dispersion 

pattern results in salt deposition and saline air concentrations that are relatively small and remain 

mostly within the site boundaries. At a 2-to-1 concentration level, the drift droplets would be 

comprised of a maximum of 40,000 ppm of salt and could cause some surface corrosion to the 

tower components and may damage vegetation in the area. To prevent the release of potentially 

harmful leacheate from the fill material, fiberglass fill is often used. 

Noise as high as 50 dba typically occurs within 3,000 ft of the tower. Similar to natural draft 

towers, noise attenuation treatments can reduce these effects, but would increase the tower costs 

by up to 25 percent. 

Blowdown from the closed-loop cooling system would have water quality constituents concentrated 

at twice the natural water body chemistry levels and slightly elevated in temperature. The cooling 

system blowdown would have to be treated and cooled to comply with applicable EPA and state 

mandated guidelines and regulations before being discharged. 

Dry Cooling Towers. A dry cooling tower rejects heat to the atmosphere in manner similar to 

the steam turbine condenser. Water or steam from the condenser is pumped through finned 

tubes, and large diameter fans force cooling air over the tube surface and the heat of the water or 

steam inside the tubes is transferred to the cooling air. There are two important differences in the 

heat transfer process between dry and wet cooling towers. The first is that the dry tower 

transfers the rejected plant heat in proportion to the difference between its operating temperature 
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and the ambient dry bulb temperature. Depending on the relative humidity, the dry bulb 

temperature can be 15°F to 20°F warmer than the wet bulb temperature and so the dry tower 

usually produces a warmer return to the plant. The second difference is that dry towers require 

about four times the air quantity needed by wet towers because the evaporative heat transfer 

process that occurs in wet cooling towers essentially humidifies the cooling air. This higher 

airflow in dry towers must be created by fans resulting in a significantly higher operating cost 

than mechanical wet draft towers. 

Dry towers do not require any water use except for a very small amount that compensates for 

piping, tubing, and pump seal leakage. Installation of dry cooling towers at an existing plant 

would virtually eliminate all environmental effects relative to the water body and air quality. No 

makeup water or blowdown discharges are necessary with a dry tower and the plume is invisible. 

However, dry cooling towers have never been retrofitted to an electric utility generating unit. 

High capital costs, high pumping and fan power requirements, extremely poor performance 

during the warm weather months, potential for freezing in winter, potential for high noise 

emissions, and high maintenance requirements make dry cooling towers impractical to retrofit at 

existing plants (Brocard and Burns, 1985). 

There are two general types of dry cooling towers, direct and indirect. As the name implies, the 

direct dry cooling tower directly condenses the steam from the turbine. A large steam duct 

carries the sub-atmospheric turbine exhaust steam from the turbine exit inside the power block 

area to a location outside the building at the dry cooling tower. Here, the turbine exhaust steam 

condenses inside finned round, square, or elliptically shaped tubing. The direct dry tower design 

replaces the condenser. To produce the transfer of the heat of condensation from the steam in the 

tubes to the ambient cooling air, a relatively large number of fans is required. The non-contact 

heat transfer coefficient of the finned tube surface is very low, and this has a significant effect 

that increases the dry direct tower size. In addition, the quantity of cooling air required is much 

greater than other types of towers. As a result, direct dry cooling towers are very large and 

require significant auxiliary power from the plant. In a direct dry cooling tower, after 

condensation, the condensate of the steam is collected and pumped back to the conventional 

plant feedwater system equipment where the steam power cycle repeats. Air in-leakage and noncondensable gases are removed from the condensation process and compressed to atmospheric 

pressure by relatively large capacity steam jet air ejectors or vacuum pumps. 

An indirect dry cooling system would use a water cooled condenser, and the heat of the 

condensing turbine exhaust steam is transferred into the cooling water within the condenser. The 

circulating water pumps typically pump the cooling water through the condenser to the cooling 

tower supply basin. Booster pumps convey the heated water to the dry cooling tower where it is 

cooled within a finned tube surface and returned again to the circulating water pumps and the 

condenser. The indirect dry tower can be more flexibly sited than the direct dry towers. Indirect 

dry towers avoid the use of the large reinforced steam duct from the turbine that would be 

difficult to route through the existing turbine building. However, the indirect dry tower 

introduces an intermediate heat transfer step that further decreases the cooling efficiency of the 

system. 
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Relative to the wet cooling tower, both the direct and indirect dry towers require significantly 

more attention and maintenance during the winter months in cold climates to prevent freezing. 

Furthermore, the dry tower designs and housings must incorporate features for operation at 

below freezing temperatures. 

Hybrid Wet-Dry Cooling Towers. Hybrid wet-dry towers utilize closed-loop air cooling systems 

for the turbine steam condensers and a separate closed-loop cooling water system with a wet 

tower to transfer heat from the condenser cooling system to the atmosphere. Concerns with 

retrofitting a hybrid wet-dry cooling tower at a plant with a once-through cooling system are 

similar to the concerns discussed above for natural and mechanical draft wet cooling towers and 

for dry cooling towers. 
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REFERENCES 

Brocard D., and J. M. Burns. 1985. Cooling Towers. In: Handbook of Energy Systems 

Engineering. J. Wiley & Sons, NY. 

Burns, J. M., J. M. Nicholson, J. H. Annet, and D. N. Alexander. 1994b. The Impacts of 

Retrofitting Cooling Towers at a Large Power Station. EPRI Cooling Tower Conference. 

Parsons Infrastructure and Technology Group, Inc. (Parsons) 2002. An Investigation of SiteSpecific Factors for Retrofitting Recirculating Cooling Towers at Existing Power Plants. 

United States Environmental Protection Agency (EPA). 2002. Technical Development 

Document for the Proposed Section 316(b) Phase II Existing Facilities Rule. Office of Science 

and Technology, Engineering and Analysis Division and the Office of Water. EPA 821-R-02-

003.