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HomeMy WebLinkAboutNotes of Meeting Bristol Bay Regional Power Plan AK. Power Authority 1982i BRI _ STONE & WEBSTER ENGINEERING CORPORATION DENVER OPERATIONS CENTER a GREENWOOD PLAZA, DENVER, COLORADO ADDRESS ALL CORRESPONDENCE TO P.O. BOX 5406, DENVER, COLORADO 80217 DESIGN CONSTRUCTION REPORTS EXAMINATIONS CONSULTING ENGINEERING NEW YORK BOSTON CHICAGO HOUSTON LOS ANGELES DENVER CHERRY HILL, N.J. PORTLAND, OREGON Mr. Eric P. Yould ReEcE! jou July 20, 1982 Executive Director Alaska Power Authority iy 2 6 YR? J.0. No. 14007.12 334 West 5th Avenue an Letter No. SWEC/PA-79 Anchorage, Alaska 99501 __. -- “7 AUTHORITY BLASS # Attn: Mr. Donald W. Baxter Project Manager Dear Mr. Baxter: NOTES OF MEETING BRISTOL BAY REGIONAL POWER PLAN ALASKA POWER AUTHORITY Enclosed for your information and files is a copy of our Notes of Meeting held at Dames & Moore in Anchorage, Alaska on June 15, 1982. We trust these notes are in accordance with your understanding. If not, please advise. Very truly yours, WL m ALE D. L. Matchett Project Manager DLM/md Enclosure Notes of Meeting sent to all attendees. PROPERTY OF: — Power Authority J.0. No. 14007.12 NOTES OF MEETING BRISTOL BAY REGIONAL POWER PLAN ALASKA POWER AUTHORITY Held in the Offices of Dames & Moore Anchorage, Alaska June 15, 1982 Present for: Alaska Power Authority (APA) Messrs. D. W. Baxter R. Fleming* E. A. Marchegiani* Stone & Webster Engineering Corporation (SWEC) Messrs. D. L. Matchett E. P. Taft Dames & Moore (D&M) Messrs. S. Grabacki R. J. Griffin J. E. Hemming J. S. Isakson Alaska Department of Fish & Game (ADF&G) Messrs. T. Arminski C. Meacham Ms. L. Shea* National Marine Fisheries Service (NMFS) Mr. B. Smith Fisheries Research Institute (FRI) Mr. P. Poe Arctic Environmental Information & Data Center Ms. J. Baldrige (AEIDC) Messrs. M. D. Kelly* J. Thiele* U. S. Fish & Wildlife Service (FWS) Ms. M. L. Nation* M Ms. A. Rarpoport *Part-time PURPOSE The meeting was held to (1) report on the spring studies made on tne Tazimina and Newhalen Rivers and (2) present a "seminar™ to interested personnel, including State and Federal agencies, on the subject of fish protection at water intakes. The seminar concentrated on problems relevant to the proposed Newhalen diversion plan. NOTES OF MEETING June 15, Page 2 SUMMARY A. 1982 Morning Meeting Ls A reconnaissance survey on the Tazimina River just above the falls was made on May 20-23, 1982, to identify resident fish that might be effected by a small diversion for a hydroelectric power plant. No fish were observed in the strong current area in the first 600 feet above the falls. The first grayling was observed about one mile upstream. The conclusion was that in the spring this area of the river is a very poor fish habitat. The spring study on the Newhalen river to investigate downstream fry and smolt migration began on May 13, 1982. Data to June 2 has been analyzed. Data will be collected until approximately the end of the week of June 14. Fry outmigration appears to be decreasing but is still occurring. Discussion followed on appropriate design criteria for fisheries protection and on future data needs. Little data is currently available on the Newhalen River at and below the proposed diversion point. ADF&G would be interested in a cooperative program to obtain more data. D. W. Baxter advised that no additional funding for the project is expected from the legislature for 1982. The Power Authority may have some other funds that could be applied. Choices will have to be made regarding future application of those funds relative to various competing data on study needs. Possible programs include (a) further data collection on the Newhalen or Tazimina (b) a public participation/information program for Bristol Bay and (c) fish protection study on the Newhalen involving a flume to test diversion of fry and smolts. Afternoon Meeting In the afternoon a seminar was held on the state-of-the-art in fish protection at water intakes and how available systems might function on the Newhalen River. A summary of the discussion is attached along with a chapter edited by E. P. Taft from the publication "Design of Water Intake Structures for Fish Protection”. DISCUSSION OF THE POTENTIAL FOR EFFECTIVELY PROTECTING DOWNSTREAM SOCKEYE SALMON MIGRANTS AT A WATER DIVERSION ON THE NEWHALEN RIVER E. P. Taft of Stone & Webster presented a two-part discussion relating to the state-of-the-art in fish protection at water intakes and how available protection systems might function with sockeye salmon fry and smolts on the Newhalen River. Information on the state-of-the-art in fish protection is presented in detail in the attached excerpted chapter of an ASCE publication entitled "Design of Water Intake Structures for Fish Protection". This chapter discusses the engineering and biological considerations which should be addressed when evaluating alternative fish protection systems for use at a specific site. As presented by Mr. Taft, available protection systems fall into one of four categories depending on their mode of operation: ° Fish Collection and Removal Concept ° Fish Diversion Concept ° Fish Deterrence Concept ° Physical Exclusion Concept Systems or devices which are included in each category are shown on Figures 1 through 4. As presented on Figure 5, evaluations of alternative designs for a given site must take into consideration the engineering practicability, potential biological effectiveness and relative costs of each alternative being evaluated. Systems which cannot be designed for reliable operation, have limited biological effectiveness for the species/life stages to be protected, or have costs which far outweigh the benefits to the fishery can be eliminated from consideration at a given site. An effective process for evaluating alternative fish protection systems is presented on Figure 6 (2 pages). This process has been initiated for the Newhalen Power Canal Diversion. Progress to date was presented by Mr. Taft, as summarized in the following discussion (with reference to Figure 6). Determine Need for Fish Protection There is agreement by all involved parties that a water diversion for power generation purposes on the Newhalen River would require the inclusion of an effective system for protecting downstream migrant sockeye salmon fry and smolts. Evaluate Alternative Designs Based on engineering practicability and potential biological effectiveness at the Newhalen site, two diversion concepts and one collection and removal concept were selected for further evaluation: ° Angled, stationary louvers ° Angled, traveling water screens ° Modified, vertical traveling water screens FIGURE 1 FISH COLLECTION AND REMOVAL SYSTEMS @ MODIFIED, VERTICAL TRAVELING WATER SCREEN @ DUAL-FLOW, TRAVELING SCREEN @ CENTER-FLOW, TRAVELING SCREEN @ FISH COLLECTION PUMPS FIGURE 2 FISH DIVERSION AND BYPASS SYSTEMS @ LOUVERS (STATIONARY AND TRAVELING) @ ANGLED, TRAVELING WATER SCREENS @ HORIZONTAL, TRAVELING WATER SCREEN @ REVOLVING DRUM SCREENS @ INCLINED PLANE SCREENS FIGURE 38 FISH DETERRENT DEVICES @ ELECTRIC SCREENS @ AIR BUBBLE CURTAINS @ HANGING CHAIN CURTAINS @ WATER JET CURTAIN @ LIGHT e SOUND @ VISUAL KEYS @ CHEMICALS @ MAGNETIC FIELDS FIGURE 4 PHYSICAL EXCLUSION SYSTEMS (PASSIVE) @ TRAVELING WATER SCREENS, LOW VELOCITY - CONVENTIONAL SCREEN - NO-WELL (DUAL-FLOW) SCREEN - DRUM SCREEN @ STATIONARY SCREENS, LOW VELOCITY @ BARRIER NETS @ POROUS ROCK DIKES e@ FILTER BEDS FIGURE S ENGINEERING PRACTICABILITY AVAILABLE TECHNOLOGY FEASIBILITY OF CONSTRUCTION OPERATIONAL RELIABILITY MAINTENANCE REQUIREMENTS POTENTIAL BIOLOGICAL EFFECTIVENESS @ PAST EXPERIENCE (LABORATORY AND/OR FULL-SCALE STUDIES) @ SPECIES COMPOSITION AND OCCURRENCE @ LIFE STAGE (EGGS, LARVAE, JUVENILES, ADULTS) ORDER-OF-MAGNITUDE COSTS @ DESIGN @ OPERATION @ CONSTRUCTION @ MAINTENANCE FIGURE 6 PROCESS FOR DEVELOPING AND EVALUATING ALTERNATIVE FISH PROTECTION SYSTEMS DETERMINE NEED FOR FISH PROTECTION IF REQUIRED, EVALUATE ALTERNATIVE DESIGNS BASED ON: - ENGINEERING PRACTICABILITY - POTENTIAL BIOLOGICAL EFFECTIVENESS - COST DEVELOP CONCEPTUAL DESIGNS AND COSTS FOR ACCEPTABLE DESIGNS (conr.) FIGURE 6 (conT.) DETERMINE NEED FOR ADDITIONAL STUDIES - BIOLOGICAL - HYDRAULIC CONDUCT NECESSARY STUDIES (BIOLOGICAL AND/OR HYDRAULIC) - LABORATORY - FIELD MAKE FINAL DETERMINATION OF DESIGN PRACTICABILITY AND COST-EFFECTIVENESS DETAILED DESIGN AND CONSTRUCTION Louvers and angled screens are designed to divert fish to bypasses for return to the source water body with minimal handling. Available data indicate that either device should be very effective in protecting sockeye smolts and that fry may also be effectively diverted. Since louvers and angled screens return fish with little or no mechanical handling, they may be preferred over a collection system such as the modified, vertical traveling water screen if the species/life stages of concern cannot survive physical removal. However, there are data which indicate that salmonids in general can survive the collection process even under relatively stringent operating conditions. Since it is possible that fry may not be effectively protected by angled screens or louvers, the modified collection screen is considered the best alternative for achieving this end. Therefore, it is included in the ongoing evaluation process. Potential Biological Effectiveness The three systems selected for further study are commercially available and have been proven to be effective in protecting a variety of fish species over a wide range of operating conditions. The following discussion presents a summary of available biological data for each system. The discussion is mostly limited to salmonid data; information on other families of fishes is given in the attached ASCE publication either directly or in the form of references. 1) Louvers A summary of louver studies and applications is given in Table 1. In addition to those systems listed, Portland General Electric is now operating a louver system to divert downstream salmon migrants past the T. W. Sullivan Hydroelectric Facility (5000 cfs) on the Williamette River. - As an indication of the high degree of diversion which can be achieved with louvers, a partial summary of study results with a variety of species/life stages is presented in Table 2. Information which is more specific to salmonids follows. The Mayfield Dam, located on the Cowlitz River in Washington, incorporates a large louver installation for diverting downstream migrants into a pipeline for return to the river below the dam. While the installation is no longer operating on a regular basis, studies have been conducted to determine diversion efficiencies. As shown on Figure 7, the facility consists of two louver bays which guide fish to bypasses. The bypasses transition into pipes which transport the fish to a secondary separator. This arrangement allows the fish to be concentrated. It should be noted that the secondary separator utilizes stationary angled screens to guide the fish to a secondary bypass. The success of this arrangement supplies evidence that angled screens (discussed later) do divert salmon outmigrants. TABLE i SUMMARY OF PAST AND PRESENT LOUVER STUDIES AND APPLICATIONS Test Test Flow Site species facilities rate (1) (2) (3) CeFs) Mayfield Dam, Cutthroat and steelhead} Prototype Washington trout, chinook and system 12,000 coho salmon, white- fish Robertson Creek, Juvenile chinook, 80 ft x 10 ft x 6 ft NA. British Columbia sockeye, and coho test flume salmon Tracy Pumping Plant, | Striped bass, King sal- | 36 ft x 5 ft x 2 ft test California mon, shad, catfish, flume, followed bya | F COO smeit, crappie, 60-ft x 6-ft x 2-ft 7 and others flume, then a prototype system Deita Pumping Plant, | Striped bass, King sal- | Test flumeand _ 6c0o California mon, white catfish prototype system d Ruth Falls, Nova Scotia Adantic salmon Prototype system [200 San Onofre Nuclear | Northern anchovy, SO ft x 6ftx4ft Generating Station, queenfish, white test flume California croaker, Full-scal e system 2 50 walleye sunperch, shiner perch Nine Mile Point Alewife, smeit, and 70 ft x 3 ft x 3 ft NA Nuciear Station coho salmon test flume New York Indian Point Nuclear | Striped bass, white 80 ft x 7 ft x 6 ft NA. Station, New York perch, Adiantic test flume tomcod Full-seale system _| 4000 Note: | ft = 0.305 m. TABLE 2 BYPASS EFFICIENCIES OF LOUVERS WITH SEVERAL SPECIES OF FISH King salmon Ring salmon Ring salmon Atlantic salmon Coho salmon Coho salmon Steelhead Steelhead Salmon fry Striped bass Striped bass Striped bass White perch Rainbow smelt Alewite White catfish White catfish Atlantic tcomcod Northern anchovy White croaker Queenfish Surt perches Size of Fish ee 717 .1-73.6 50-150 >85 Smolt 62-85 >85 >85 193 <35 1634 Yearling 5-125 Yearling 62-85 62-85 10-12.5 75-100 60-150 100-300 100—300 60-300 Approach Velocity (m/s) 0 .65-0 .97 0.46-1.07 0.88-7.10 0.24=1.07 0.30 0.88-7.10 0.388-1.10 0.40-1.10 0.38-1.10 0.52-0.89 0.91 0.46-1.07 0.91 0.30 0.30 0.46-0.61 0.46-0.67 0.91 1.82.1 1.38-2.1 1.38=2.17 1.32.1 Etficiency a) 93-97 60-100 74-81 30 38-100 62-66 74=79 63-96 69 90-99 98-100 69 84 98-100 38-100 4 68 97 93-37 95-100 95-100 95-100 8" FISH BYPASS ENTRANCE SOUTH LOUVER SAY Two years of studies at Mayfield produced the data presented in Table 3. Despite continuous design, operational and maintenance problems, the louver system was reasonably effective in diverting the species evaluated. An interesting note which again supports the angled screen concept is that when the louver arrays were completely covered with wire screen mesh, total diversion resulted. From 1957 to 1962, extensive studies were conducted with louvers at two flume facilities: Puntledge River and Robertson Creek. These studies supply the only guidance information on sockeye salmon. The test facilities both evaluated a louver array, ranging from 50 to 100 ft. long, set at a 12 degree angle to the flow. Louver bar spacings ranged from 2 to 6 in. Approach velocities ranged from 1 to 4 fps. A summary of results obtained is presented in Table 4. A total of nearly 92,000 sockeye smolts, ranging in length from 60 to 90 mm, were tested in the facilities. Very high diversion efficiencies of 85 to 95 percent were obtained. Coho smolts (20,500 individuals), measuring 80 to 120 mm showed the same level of diversion efficiency. Data on chinook and coho fry demonstrate an apparent species-specific difference in diversion capability (Figures 8 and 9). While chinook fry guided with a reasonably high efficiency, coho fry consistently displayed a limited ability to guide along the louvers. Such data demonstrate the need to evaluate the diversion capability of the species of concern at a given site. Another interesting finding of these studies was that while sockeye smolts and chinook fry showed a trend toward increasing diversion efficiency with an increase in approach velocity (1.5 to 2.5 fps), as shown on Figure 9, such a trend was not evident for coho smolts and fry. A final example of louver system efficiency comes from data gathered at the Tracy Diversion Project in California. As shown on Table 5, chinook salmon and striped bass displayed a high degree of guidance at this large-scale (5000 cfs) water diversion. Numerous additional studies have been conducted which demonstrate the high diversion potential of louvers with a variety of fish species and life stages. This information can be drawn from discussions and references given in the attached ASCE publication. 2) Angled Screens Angled screens have been studied extensively for use at steam electric station water intakes for protecting a wide variety of fish in freshwater, riverine, estuarine and marine environments Since most of this work has not been conducted with salmonids, it will not be discussed herein. However, a complete description of the studies is given in the attached ASCE publication. It should be noted that in all angled screen studies conducted to date, diversion efficiencies of nearly 100 percent have been achieved under all test conditions. Thus, the angled screen concept can be considered a proven design. TABLE 3 LOUVER DIVERSION EFFICIENCIES MAYFIELD DAM CHINOOK COHO STEELHEAD FRY | YEAR SALMON SALMON TROUT = (<85mm) 1964 81.6 66.5 74.6 64.6 1965 82.3 74.6 86.7. NOT TESTED (x100-150 »m) (110-146 mm) (~ (75 mm ) 4“FERY” includes coho, chinook, steel- head and cutthroat fry under 85mm TABLE 4 LOUVER DIVERSION EFFICIENCIES SUMMARY OF RESULTS PUNTLEDGE RIVER/ ROBERTSON CREEK 1957 - 1962 SOCKEYE SMOLTS 85 - 95% COHO SMOLTS 85 - 95% CHINOOK FRY __ 65-75% COHO FRY 20 - 30% PERCENT GUIDING EFFICIENCY FIGURE @& 100 SOCKEYE SMOLTS 90 80 7OFr CHINOOK FRY 60 50 40 1.0 15 2.0 25 30 35 APPROACH VELOCITY (FEET/SECOND) Approach Velocity and Mean Guiding Efficiency of Sockeye Smolts and Chinook Fry, Robertson Creek, 1962, Using a 12-inch-wide Bypass. The Bar Length Represents Plus and Minus Two Standard Deviations FIGURE 1 COHO SMOLTS COHO FRY PERCENT GUIDING EFFICIENCY 1p LS 29 25 3.0 3.5 APPROACH VELOCITY (FEET/SECOND) Approach Velocity and Mean Guiding Efficiency of Coho Smolts and Coho Fry, Robertson Creek, 1962, Using a 12-inch-wide Bypass, The Bar Length Represents Plus and Minus Two Standard Deviations ") HE_E sp LOUVER DIVERSION EFFICIENCIES SUMMARY OF RESULTS TRACY DIVERSION PROJECT CHINOOK SALMON (71 - 74mm) 93 - 97% STRIPED BASS = (16 - 34 mm) 90 - 99% VELOCITIES = 1.4 - 4.5 fps LOUVER ANGLE = 16 deg. SLAT SPACING = 1 - 3.5 in. REF.: BATES AND VINSONHALER'- 1956 Two angled screen studies have been conducted with salmon. At the North Fork Hydroelectric Complex on the Clackamas River in Oregon, two angled screen diversion systems are used to divert downstream migrants. As shown on Figure 10, the first system is located in a downstream migrant channel. Two screens, set in tandem at a 22 degree angle to the flow, divert salmon into a fish ladder which carries them to the second angled screen. This screen, shown on Figure 11, is set in the fish ladder at a 45 degree angle to the flow. Downstream migrants are diverted at this point into a 5-mile long pipeline which carries them past two additional dams to a release point. Both angled screen systems have operated effectively in diverting all salmon outmigrants for many years. The second angled screen study with salmon was conducted in Troy, Oregon as part of an evaluation of a novel horizontal traveling screen (HTS). While the HTS was never fully developed, results of diversion studies with chinook salmon fingerlings support the angled screen concept. As shown on Figure 12, the prototype test facility was used to conduct both diversion and impingement survival tests. Survival tests will be discussed later. The results of diversion tests with 70 and 170 mm chinook salmon are given in Table 6. It is clear that diversion is very high under all conditions tested. The two angled screen studies with salmon, coupled with other extensive information on diversion with other species, indicate that an angled screen system offers a high potential for diverting sockeye smolts in the Newhalen River. It is probable that fry would divert to a great extent also. However, data are not presently available to determine the level of effectiveness which might be achieved. Accordingly, the possibility of impingement on the screen should be considered. For this reason, evaluation of a modified, traveling water screen (TWS) for gently collecting and returning fish to the river is appropriate. Data to support this collection concept are presented below. 3) Modified, Traveling Water Screens Most steam electric stations in the United States have incorporated through-flow traveling water screens into the intake system to filter out debris. When concern arose in the early 1970's over the mortality of sometimes large numbers of fish which were drawn into intakes and impinged on the screens, efforts began to modify the standard TWS (Figure 13) to safely collect incoming fish. There now exist numerous modified screen installations around the country which are effectively collecting and returning fish to the source water body. Data from studies with species other than salmon are presented in the attached ASCE publication. Salmonid data are presented below. As previously mentioned, the HTS evaluation involved impingement survival testing in addition to diversion testing (Figure 12). As part of that evaluation, additional survival studies were conducted in a laboratory in Seattle. Tests were conducted with chinook sac-, swim-up, and button-up fry. Results are presented in Table 7 and Figure 14. It is evident that FIGURE /O EXIT OF THE FISH LADDER AND THE DOWNSTREAM-MIGRANT COLLECTION FACILITY PORTS FROM UPSTREAM MIGRANT LADDER EXTENSIONS ORIFICE TO FISH LADDER TO DOWNSTREAM MIGRANT CHANNE oAauY eo Te ee EES = a8 = “ready pue “ ee ny SIDE VIEW MIGRANT CHANNEL TRAVELING ee \e za C. = SCREENS NSIONs i. Yi , (se PORTS FROM UPSTREAM MIGRANT LADDER Y Si EXTENSIONS TO DOWNSIREAM MIGRANT CHANNEL Vi ZV \GA et WO 4) RESERVOIR “ >) of STRUCTURE AT NORTH FORK DAM FIGURE [I SEPARATOR STRUCTURE PIPELINE ENTRANCE DOWNSTREAM MIGRANT PASSAGE -—=-____~"4- Lappe _! TRAVELING = ces SCREEN UPSTREAM MIGRANT PASSAGE NORTH FORK FISH SEPARATOR COLLECTION FIGURE I2 250' [ INCLINED SCREEN PARTITION WALL HORIZONTAL = ©: \ TRAVELLING A) @ GUIDE WALL PUMP TEST FLUME FISH RELEASE AREAS @ DIVERSION TEST (170mm FINGERLING ) @ 'IMPINGEMENT TEST (26 and 35mm FRY) POST-TEST @ By-Pass TEST ts ACCLIMATION HOLDING @ DIVERSION TEST (70mm FINGERLING) RACEWAYS Plan View of Try Test Flume Showing Installation of Horizontal Traveling Screen Model VII (HTS VII) : Inclined Screen and Fish Holding Areas TABLE 6 SUMMARY OF RESULTS HTS DIVERSION EFFICIENCY SPRING CHINOOK SALMON 70 mm SALMON 170 _mm_ SALMON APPROACH TIME OF DIVERSION DIVERSION VELOCITY DAY E Cc iC ) SURVIVAL(%) EFFICIENCY(%) SURVIVAL(%) 0.5 fps Day 99.8 97.4 Night 98.4 97.6 98.6 100.0 1.5 fps Day 97.9 98.5 99.6 99.7 Night O15 99.7 99.8 99.9 Prentice and Ossiander 1974 FIGURE [3 THROUGH-FLOW TRAVELING SCREENS LOW PRESSURE | JET SPRAY NOZZLES MOTOR HOUSING ORIVE MECHANISM ORGANISM TROUGH CHAIN DRIVE TABLE 7 Diversion Efficiency and Survival of Spring Chinook Fry in Relation to Approach Velocity and the Duration of Impingement on HTS VII Norma] 26 mm Sac fry ____35 nm Buttoned-up fry approach Duration of Number Diversion Number Diversion velocity impingement of efficiency Survival of efficiency Survival ft/sec} (Minutes) tests (Percent) (Percent) tests (Percent) (Percent) 0.5 6 12 99.4 100.0 - - - 30 VW 99.5 100.0 - - - 60 12 91.1 99.4 - = - 15 2 9 99.8 98.5 - - - 6 14 97.8 99.7 9 98.7 100.0 15 12 98.9 99.6 6 97.6 94.3 30 6 96.5 90.6 2 99.8 82.1 60 2 96.6 39.1 2 98.4 21.5 FIGURE |4 70 60 wn oO SURVIVAL (PERCENT) ey ° LEGEND —---— sac fry swim-up fry 20 | —-— buttoned-up fry © 0.5 fps (Troy) + |.Ofps (Seattle) 10 | X 1.5 fps ( Troy ) 4, A 2.0 fps (Seattle) © @ 3.0 fps (Seattle) 0 10 20 30 40 50 60 DURATION OF IMPINGEMENT (Minutes ) Relationship between Duration of Impingement and Percent Survival of Salmonid Test Groups at Various Normal Velocities very high survival of chinook salmon fry can be achieved even when the fish are impinged at high velocity for periods under 10 minutes. At lower velocities, impingement durations as long as one hour result in nearly 100 percent. These data, coupled with data for other species, indicate a high potential for effective protection of sockeye salmon fry at Newhalen should a collection device (i.e., modified TWS) be required. Develop Conceptual Designs Returning to Figure 6, it can be seen that, once alternative fish protection systems have been identified for further evaluation, the next step in the process is to develop conceptual designs for these alternatives. Several conceptual arrangements have been developed for incorporating louvers, angled screens or modified TWS into an intake canal at the Newhalen site. Determine the Need for Additional Studies On the basis of the available data, there appears to be a high potential for effective application of louvers, angled screens or modified TWS at the Newhalen site. However, given the lack of information on sockeye fry and smolts, it was the opinion of the State agencies that in situ biological studies should be conducted to demonstrate the potential effectiveness of the three alternative fish protection systems with these life stages. A scope of work will be prepared for such an effort. Should these studies be conducted and should positive results be obtained, a final determination of design practicability and cost-effectiveness will be made (Figure 6) prior to detailed design. EDWARD P. TAFT Design Of ‘Water Intake Structures For Fish Protection Prepared by the Task Committee on Fish-Handling Capability of Intake Structures of the Committee on Hydraulic Structures of the Hydraulics Division of the American Society of Civil Engineers ami Rican SOCK oF Published by the American Soctety,of Civil Engineers 345 East 47th Street New York, New York 10017 SECTION IV PRACTICAL FISH PROTECTION METHODS GENERAL INTRODUCTION The engineering elements of water intake and screening methods which have been effective in substantially reducing fish mortality and which can be used without extensive further engineering research are summarized in this section, Dimensional and general geometry guidelines, where appropriate, are in- cluded to assist designers who are not in a position to undertake the engineer- ing research often necessary to develop sophisticated and effective fish pro- tection facilities. It must be emphasized, however, that detailed design of a fully acceptable intake in an environmentally sensitive water source May re- quire more comprehensive engineering information than is available in this monograph. The design of fish protection features for water intakes is severly limit- ed by the availability of proven technology. Many of the mechanical and be- havioral approaches to fish protection are either limited in effectiveness or involve teatures which have not been developed to the point of engineering There are types of commercial screens which are not well adapted For general reference purposes this practicality. to modification for fish protection. section also includes very brief descriptions of these technologies and their limitations. lt is important to keep in mind two factors when considering the intake design for a specific site a. Although the effective fish protection methods discussed in this section have been well developed from an engineering standpoint, they will not necessarily apply to the specific physical and bio- logical conditions for a given site. The engineer must consider site adaptation of the intake and the bivlogist must undertake what- ever research is necessary to determine the effectiveness of the type of intake being proposed. for example, it will not be practi- cal to use a fish impingement and recovery system where the specific species of fish will not survive physical handling. In this case, fish guidance and recovery will be wore appropriate. 24 FISH PROTECTION METHODS b. Many of the mechanical and behavioral fish protection methods placed in the category of limited effectiveness may have value in reducing fish mortality in specific situations. A given intake system de- sign way be improved in overall effectiveness by incorporating features which do not otherwise have a general applicability. CRITERIA FOR PRACTICAL FISH PROTECTION METHODS A fish protection device or system must meet certain criteria to be termed practical, in the context of this section. The facility must be: a. Substantially effective in protecting aquatic life. b. Available today without further mechanical development. Cc. Maintainable without interfering with the high reliability required of cooling water supplies. d. Capable of fulfilling all the requirements of the site, including debris handling and effective operation over the full range of water levels expected. e. Cost effective. INTAKE LOCATION TO AVOID CONCENTRATIONS OF AQUATIC LIFE ae any given intake site there may be locations in the-area where concen- oes of aquatic life is minimum, as determined by biological field studies This location could be onshore, offshore, deep or shallow, and may vary with , season or time of day. The intake should be so located that it does not attract fish and does not tend to modify water current patterns in a manner a ish Fig. IV-1 illustrates shoreline, offshore, and channel loca- a ee typical configurations comnonly selected to draw water I Choice of the point of water intake is site specific. Some general selec- tion factors to consider are as follows: a. Screen structures aligned flush with the natural shoreline, Fig. IV-1A : e . may attract fewer fish than those placed at the end of a channel cut into the shoreline, Fig. IV-1C. The presence of an offshore velocity cap structure, Fig. IV-2C, or other offshore intake may attract fish concentrations that were not there before the structure was put in place some west coast ocean intakes. This has happened at 25 26 WATER INTAKE SERUCTURES ‘ WATER \ —> TO POWER PLANT SOURCE A-—INTAKE FLUSH WITH SHORELINE SOURCE \4 a ae TO POWER PLANT GS : ' NLET i 4 4 B—OFFSHORE INLET == t p= 10 SOURCE POWER PLANT | WATER ao fon C—OPEN CANAL TO INTAKE STRUCTURE Figure IV-1 INTAKE LOCATION WITH RESPECT TO SHORELINE DEEP INTAKE (INF ILTRATION) EREATION) (E) FISH PROTECTION METHODS 27 SCREEN SCREEN Lip O SURFACE INTAKE (A) DEEP_INTAKE (B) GATED OPENINGS DEEP INTAKE (VELOCITY CAP) Cc “a MULTI LEVEL INTAKE SLE EVEL INTAKE (D) SCREEN. SIPHON PIPE SURFACE INTAKE -(SIPHON) AE SIPHON) (F) Figure 1V-2 SURFACE AND DEEP INTAKES 28 WATER INTAKE STRUCTURES Some types and locations of intakes may be hazardous to navigation, may present unacceptable construction problems, may be difficult to reach for operation or maintenance, or may be aesthetically un- acceptable. A complex intake design such as the multilevel intake illustrated in Fig. IV-2D might be of interest in theory but can be too compli- cated for construction and operation, therefore, no longer satisfying the criterion for practical design. GEOMETRY OF WATERWAYS The geometry of intake structures can create eddies and local dead water areas which may be either detrimental to or beneficial for fish protection. Intake geometry must be evaluated for effect on fish. Following are typical examples of common configurations which influence flow patterns in a manner which may be significant for fish protection. Extension of the intake structure into the waterway as shown in Fig. IV-3A will result in eddies downstream of such intakes and way encourage fish concentrations including predators. Since the eddy area is close to the point of water inflow, there is the possibility of drawing in fish. Fig. IV-3B shows an improved location for the intake structure with the screens essentially flush with the shore- line. Curtain walls, as shown in Figs. I11-4B and IV-2B, are often pro- vided to draw in cooler water from thermally stratified waterways, to reduce the intake of floating debris, or to eliminate the entry of cold air into the structure. From a fish protection standpoint, such curtain walls can create fish traps if no fish removal facili- ties are provided. On the other hand, the tendency of fish to remain in the dead water created by the curtain wall will concentrate them for removal by fish pump if a concentration-removal facility is determined to be a desirable fish protection feature for a given intake situation. Miscellaneous dead water areas can be created by structural fea- tures. Pier details that will influence fish activity are shown in Figs. IV-3C and IV-3D. Pointed or rounded piers will eliminate dead water areas and guide fish directly into the screen. This can be beneficial if a fish lifting and recovery system is pro- RIVER FLOW RIVER FLOW——~ ‘SCREENS SCREENS ° 2 a 2 « E ° « a 4 a = SHORE LINE AREA OF WATER EDDIES 2 uw « So x ao ¢ PUMPS FISH PROTECTION METHODS a IMPROVED DESIGN POOR DESIGN ISH GUIDED TO SCREEN FACE — FI \ Figure IV-3 SOME HYDRAULIC DESIGN FEATURES WHICH INFLUENCE FISH EPA (Ref. 27) L | a, | { ales IN THIS AREA t ic 29° Source: w WALER INTAKE STRUCTURES vided but detrimental if a fish resting area is desired as in the transverse fish escape passage design described later for flush mounted screens. RESTRICTED WATER VELOCITIES IN SCREEN APPROACH PASSAGES It is common practice to limit the water velocity approaching the face of conventional screens to a figure which permits small fish to escape. Water velocity criteria and contro] were discussed in detail in SECTION III. VERTICAL TRAVELING SCREENS Vertical traveling screens are provided as standard equipment in al) major water intakes for the primary purpose of protecting the downstream water sys- tem leading to a power plant or other facility. The primary purpose of the screen is to exclude debris. The text immediately following covers only screen wodifications to protect aquatic organisms. Basic engineering design of the three most common types of vertical traveling screens is included at the end of this section. FLUSH MOUNTING OF VERTICAL TRAVELING SCREENS Flush mounting of traveling screens with associated features described below is a relatively minor modification of a conventional through-flow travel- ing screen facility. This arrangement can permit the fish to escape from the area immediately in front of the screens. A conventional screen setting is shown in Fig. IV-4A and a flush mounted setting is shown in Fig. IV-4B. Fig. IV-5A shows the flush interior wall and the fish escape port in the outside wall of an otherwise conventional intake. These changes require only a minor modification of the typical intake cross section shown in Fig. III-1. In summary, the modification consists of the following features: i The interior screen supporting walls are terminated flush with the traveling screen face and shoreline instead of extending to the structure entrance, 2. Openings are constructed in the outside walls of the structure. These openings are usually flush with the screen face, extending from the structure bottom to the high water level (or below low water level in cold regions) and are at least four to five feet wide. Trash bars must be provided for these openings as well as for the front entrances of the intake structure. FISH PROTECTION METHODS uM SCREEN WELLS . TRASH BARS (FISH ENTRAPMENT AREAS) SHORE om : CONVENTIONAL SCREEN SETTING "a" —~—RIVER FLOW ~~ FISH PASSAGE TRASH BARS “FLUSH"MOUNTING OF SCREEN INFLOW SHORE LINE y MODIFIED SCREEN SETTING Yo" 8B Fiqure IV-4 FLUSH MOUNTED SCREENS 32 WATER INTAKE STRUCTURES 9° & = Ww = oO wo | a ae 3 - | << # z\ti rf 4 | # fla uJ) a 8 YW w z 2 6 ao 7? eae a 3 = gf a a ws Go & - jue ne eo iz aol z= oe gee au 3 Seu 23 aaa ze z TRASH RAKE WIN WTR NORMAL HIGH LEVEL WATER i DETAIL C FISH PASSAGE IN OUTSIDE WALLS TYPICAL SECTION A Figure IV-5 FLUSH MOUNTED SCREEN WITH FISH ESCAPE PORT FISH PROTECTION METHODS 35 The screens themselves may be modified in such a manner that the basket side plates do not extend beyond the front face of the screen mesh as shown schematically in Fig. IV-5C. conventional side plate. Fig. IV-5B shows the If elimination of this side plate does not significantly benefit species of fish under consideration, it can be retained. Upstream and downstream outside of the structure, the two fish escape channels lead fr way. the exterior wall openings back to the main water- Exterior excavation and wing wall design must provide gradual bottom and side slopes for fish return to the water source. The purpose of this modification is to permit fish to swim directly to the right or left of the screen face and ultimately to escape from the structure. Without such openings fish will in general remain trapped in the area since they do not usually swim back out of a confined screen entrance channel. Even in relatively fast flowing rivers the intake flow induced by the pumps generally causes inflow through both of the exterior side-wall fish escape passages. Also, when these passages are used, they must be gated or stop logged if isolation of the screens is desired for maintenance. There is little data available to quantitatively define the effectiveness of the flush mounting modification. For long lines of screens positioned per- pendicular to the incoming water and/or for certain species and sizes of fish, the fish recovery efficiency may be low. however, and offers sow The modification is relatively modest, asure of fish protection for most vertical traveling Accordingly, it is recommended for consideration. screen situations. FISH COLLECTION AND REMOVAL CONCEPT TRAVELING SCREEN MODIFIED WITH FISH LIFTING AND FISH RECOVERY SYSTEM Standard designs are now available from all U.S. traveling screen manu- facturers to achieve lifting and recovery of impinged fish. This modification as high as 90 percent effective for those species of fish which can withstand the trauma of short t herent in the has been shown to be we impingement and the handling in- ecovery system, 3B M WATER INTAKE SERUCTURES Lifting and recovery systews are applicable to all three of the travel- ing screen types described at the end of this chapter (through-flow, dual flow and center flow), but research to date has concentrated on modifications to the throuyh-flow screen which has been the only type of screen used extensively in the United States, Fig. IV-6 shows three variations of the fish lifting and recovery system specifically applied to through-flow screens. The following features are common to all systems: as Fish holding buckets in place of the normal screen lifting lips. The buckets hold about two inches of water and permit fish to stay in water while being lifted to the fish recovery system, b. A low pressure spray or deluge system to rewove the fish gently from the fish holding buckets. A fish sluice separate from or combined with the debris sluice. d. A conventional high pressure debris spray and sluice system in addi- tion to the fish removal system, e. Heavy duty mechanical parts to permit continuous operation, Fig. IV-6A shows a fish recovery backwash system similar to that tested and used at the Surry Station of the Virginia Electric and Power Company (1). Figs. IV-6B and IV-6C are alternative designs showing front wash and combined front wash and back wash. The comparative performances of the three schemes frow a biological stand point have not yet been investigated in enough detail to permit firm recommendations. Some of the biological aspects of the wash systems are discussed in SECTION V in connection with the use of fine mesh screening material for traveling screens. Since the concept of fish recovery is relatively new, the fish recovery features are undergoing Continuous modi- fications and improvement. When these modified screens are being used for fish recovery, they must be operated frequently or even Continuously to keep fish impingement tine to a minimum, The frequency of operation must be determined on the basis of the ability of local species to withstand impingement stresses. The potential for wear of moving parts is much greater for a screen operated frequently or con- tinuously than for standard traveling screens, which normally operate inter- mittently, The screen must be designed for this increased service. The utili- zation of heavy duty Chains, roller bearings at the head shaft, journal bush- inys at the foot shaft, light weight components, and provisions for proper slack tensioning will help to reduce operational problems and maintenance re- quirements (2). FISH PROTECTION METHODS 34 HSH wasnunsss System GENECION [Ld Hsu f J Mover al 7 | COnvertorat fuGr PRESSuae Seaay —> TRAY TRave: | AVERAGE WATER ELEVATION WATER FLOW A i —t BACK WASH Courtesy of: Envirex "Front was : H Courtesy of: FHC Corp. FRONT WASH-BACK WASH Figure IV-6 FISH RECOVERY SYSTEMS FOR VERTICAL TRAVELING SCREENS Courtesy of: FNC Corp. 36 WATER INTAKE STRUCTURES The fish sluiceway returning the fish to safe waters must be designed properly to reduce fish trauma in accordance with the principles set forth in SECTION VI, FISH RETURN SYSTEMS. Biological Considerations - All traveling screen types that rely on the col- lection and removal of fish from screening media are similar, Therefore, avail- able data on the impingement survival of fish on screens serve to support all screen types. Also, data on survival of juvenile and adult fishes generally support the impingement concept but are not refined to the point where one type of screen can be considered potentially more effective than another, There is only one operating power plant with a modified traveling screen and spray-wash system which has been biologically evaluated in detail (1). The Surry Power Station of Virginia Electric and Power Company is situated on the James River and withdraws 3,740 cfs (105 w?/sec) of water for condenser cooling. The operating experience of modified traveling screens with respect to biologi- cal effectiveness is described in the following paragraphs. Screen modification involved bolting steel] troughs on the trash lips of the conventional screen baskets. The troughs extend approximately 5 in. (13 cm) from the screen face and are capable of maintaining a minimum water depth of 2 in. (5 cm) during screen rotation. This arrangewent prevents fish from flip- ping off the screen and becoming reimpinged and also ensures that the fish are in water as they are lifted to the point of release. Collected fish are carried over the headshaft sprocket and either fall into a collection trough or are gen- tly washed into the trough with a low pressure jet, 15-20 psi (104-138 kPa) on the back side of the screen. The low pressure wash feature on the modified screen minimizes the damage caused by conventional spray-wash systems. To ensure maximum survival of impinged fish, the modified screens are Operated continuously at a speed of 10 fpm (3.05 m/min). Consequently, fish are nol impinged on the screen mesh for wore than 2 minutes. In 18 months of opera- tion, the modified screens have shown a high degree of success in collecting fish while maintaining low mortality (1). Short-term holding studies (approxi- tately 15 minutes) show that, on the average, survival of 58 fish species was 93.3 percent. Average survival of 19 freshwater species was 98.) percent. Although modified screens appear to have good potential for alleviating impingement mortality, it should be pointed out that short-term mortality Studies alone may not adequately reflect possible longer term mortality which FISH PROTECTION METHODS aw way result from injury incurred during the impingement and removal process, particularly among less hardy species. On the basis of impingement survival data collected for 5 species at a power plant located on the Hudson River, it has been sugyested that inmediate survival may be a poor indication of impinge- ment mortality and that some consideration of latent mortality is required for adequate assessment of impingement damage (3). The data offered in support of this statement are given in TABLE IV-1. It can be seen from Table IV-1 that while initial survival of four species was high, mortality increased rapidly over the 96-hour holding period, parti- cularly for the relatively fragile gizzard shad and Alosa spp. Additional studies at other power plants on the Hudson River further indicate that latent mortality may be a better indication of impingement damage. for example, at the Bowline Point Generating Station, initial survival of young-of-the-year white perch and striped bass impinged on continuously operated screens was high, ranging from 81 to 98 percent for white perch and 89 to 98 percent for striped bass. Mortality increased, however, during the holding period with survival after 96 hours ranging from 55 to 56 percent (white perch) and 52 to 81 percent (striped bass). Similar trends were noted at Roseton and Danskanmer Point Generating Stations (4). TABLE IV-1 IMPINGEMENT SURVIVAL AT A HUDSON RIVER POWER PLANT? No. of Percent Survival Species Fish? Initial = 6hr 12hr 24 hr 48 hr 96 or White perch 439 94 -- -- val 63 50 Striped bass 45 93 -- 62 44 18 n Gizzard shad 10 . 98 58 25 W 0.5 0.5 Alosa spp. 49 70 8 2 0 0 0 Controls White perch 38 100 100 100 100 100 100 Gizzard shad n 100 100 100 100 82 82 Notes: a. Based on Ecological Analysts, Inc. 1976 (3) b. summary of 3 to 6 sampling dates. There are several reasons why the Hudson River data should not be considered contradictory to the results obtained at the Surry Power Station. First, the Hudson River studies were conducted at plants which do not incorporate modified A Ra nc 4B WALER INTAKE SERUCTURES screens (i.e., lifting buckets). Therefore, there was a good chance that fish could drop off the flat debris lip as it cleared the water surface and be re- impinged one or wore times, Those fish which were retained by the lip were out of water for a period of time and, in some cases, were exposed to relatively high pressure sprays. further, standard shallow, rough concrete sluiceways were generally used to convey fish to a collection area. All these factors may have biased the results toward high mortality. Therefore, it is possible that modi- fication of the traveling screens (incorporation of lifting troughs, low pressure sprays, and an appropriate return system) would increase survival rates. Survival potential also appears to be species specific. For certain species, initial survival may be a valid indication of impingement damage. for example, 96-hour impingement mortality studies using yellow perch were conducted at the J.P. Pulliam Power Plant in Wisconsin during 1977 (5). Initial survival of yellow perch was high under two different test conditions: 1) impingement only and 2) impingement plus screenwashing. During the impingement only study, impinged fish were handpicked off the screens and placed in holding tanks. Initial survival was high ranging from 84 to 100 percent. Survival after 96 hours did not drop appreciably. The lowest survival rate (79.2 percent) was believed to be the result of overcrowding in the holding tank and warm water temperatures 77°F (25"C). Mean 96-hour survival (total of 4 tests) was 82.) percent (5). During the impingement-screenwash study, the use of the high pressure wash (70 psi (483 kPa)) did not increase mortality. Survival rates of impinged fish after 96 hours ranged from 73.3 to 100 percent. Survival for six tests was actually higher in the impingement-screenwash study with a mean of 87.8 percent (5). The increase in percent survival in this study was attributed to lower water temperatures, elimination of Crowding stress in the holding tanks, and size of the fish (perch used during the impingement only study) averaged 5.9 in. (14.9 cu) while perch used in the impingement plus screea- wash study were almost all young-of-the-year fish, averaging 4 in. (10.2 cm) in length (5). Thus, it is apparent that while latent survival is probably the best indi- cation of impingement damage for fragile species such as Clupeids, initial survival may be an appropriate measurement of impingement impact for some of the hardier species, such as yellow perch. FISH PROTECTION METHODS W Although modified screens may be somewhat less effective on a long-term survival basis than the Surry results indicate, it is believed that the excellent short-term survival observed at that site fully warrants considera- tion of this screening concept. The high survival achieved among the rela- tively fragile cClupeids indicates that the modified screen system, incorporat- ing a well designed means of transportation, could greatly reduce impingement mortality. It is believed that modified screens offer a potentially effec- tive means of minimizing losses of juvenile and adult fishes. FISH COLLECTION PUMPS Various types of pumps have been utilized in the past for the collection and transport of fish with good success. For this reason, pumps have been seriously considered for application at power plants to collect and safely remove entrapped fish from intake screenwells. An example of this concept is shown in Figs, IV-7 and IV-8 and is described below. Fish which become trapped in the screen area are simply pumped out by a type of pump which will do little or no damage to the fish. The intake design should be such that the fish will tend to concentrate in a limited area where the pumping operation will be effective. Such a system was installed by Detroit Edison Company for all four units of the Monroe Power Plant on Lake Erie after an extensive evaluation of the con- cept in two intake bays of the Unit 2 screenhouse. The experimental fish pump- ing system was installed in August, 1973. The system consisted of two barrier screens, two collection pans, piping elements, and a volute pump as shown in Figs. IV-7 and 1V-8. The collecting pans were located near the bottom of the existing skinmer walls directly in front of and facing the traveling screens. They were mounted horizontally and measured 12.8 ft (3.9 m) wide by 8 in. (20.3 cm) deep. The barrier screens were installed to prevent fish from penetrating the area above the collecting pans and behind the skinmer wall. The volute pump had a 1.7 ft (0.5-m) diameter impeller with two channels and was rated at a capacity ranging from 2.6 to 8.2 cfs (0.074 to 0.232 w/sec). The piping system consisted of two 8-in. (20.3 cm) pipes, leading from each of the two collecting pans, which wyed into a comuon 10 in. (25.4-cm) pipe con- necting to the pump, After 4 months of operation, modifications were made to the pumping sys- tem to enhance collection efficiency. The bottom lip of the collecting pan was removed and a flexible barrier was placed above the pan to guide fish 40 WATER INTAKE SERUCTURES cs = | ‘OD A 4) | Ke Y ULL 3 ! y TRASH | P ce y RACK | : j WATER ! | y be SURFACE i BAKKER ; pontawl y i IPs of, fs J To'Puant aN ] “T ut —— I \ || -_ sees Figure IV-7 FISH PUMP Courtesy of: Detroit Edison Company FISH PROTECTION METHODS Figure IV-8 FISH COLLECTOR AND PUMP SCHEME Courtesy of: Detroit Edison Company PUMP SUCTION 4 42 WATER INTAKE STRUCTURES into the collector, To increase the size of the collecting pan opening, the horizontal barrier screens were relocated and holes were cut in the bottom of the pan. In addition, two incandescent underwater lights were installed in the collector cover to help attract fish to the pan. Modifications were also made to the piping system and holding pool in an attempt to reduce mortality in the pumping systems. In the final four unit design, fish were returned to a discharge point in Lake Erie via a 32 in. (81.3 cm) diameter, 4,400 ft (1,341 m) long polyethy- lene pipe. A complete description of the biological studies conducted with the fish pumping system at Monroe is presented in separate reports (6)(7). In brief, these studies showed that the pumping system reduced existing impingement of gizzard shad by more than 70 percent and that latent mortality is low. It is believed that a fish pump system offers a potentially effective alternative for reducing juvenile and adult fish losses at power plants. How- ever, the success of such a system will be species-specific and will be strong- ly influenced by the ability to establish proper hydraulic and structural conditions within a screenwell. It would appear that the pump system would be most effective in collecting fishes which typically reside in the upper por- tion of the water column. Because this system relies on movement of the fish prior to collection, it is not effective for use in collecting nonmotile planktonic forms. MISCELLANEOUS FISH COLLECTION AND REMOVAL CONCEPTS General - There are several commercial mechanical screens, other than the travel- ing types previously discussed, which have been widely used outside the United States. These include a number of variations of circular drum-like single axis rotating screens which are briefly described below. With a few exceptions these screens have not been equipped for fish recovery. However, some type of fish lifting lip with appropriate supplementary spray sys- tems could be incorporated into them, in a manner similar to that previously described for vertical traveling screens. There is little present evidence to indicate that these screens offer any fish protection advantage over those in common use in the United States. Claimed engineering advantages for these screens include simplicity, in that there are fewer moving parts than in the revolving band type screens; ease of maintenance, in that at low water the axis is dry and can be easily serviced; FISH PROTECTION METHODS ay and finally that carry-over into the clean water side cannot occur. In general, _ however, the size of the structure required to mount such screens is substan- tially larger than would be required for traveling screens of similar capacity. All these screens are cleaned in a manner similar to the revolving band screens previously described. Water jets wash materials into a flume or cart for disposal. Several rows of such jets might be provided for heavy debris conditions. These screens are limited to relatively smal] water level variations since under normal conditions the horizontal axis should be above the water level. Single Entry Rotating Drum Screen - Fig. IV-9 shows the principle features of the single entry drum screen. Water enters only one end of the rotating cylinder, which is open and without mesh, and exits through the screened per- iphery. The axle is supported as a cantilever from the back side of the drum. Because of the unbalanced nature of this support the screen is limited in dia- meter (weight consideration) to say 30 ft (9.14 m). It is thus suited only to low capacity intakes, The backside of the cylinder is sealed by a solid backplate. As noted above, the screen is cleaned by water jets at a point above the water level. Double Entry Rotating Drum Screen - Fig. IV-10 shows the principle features of the double entry drum screen, and Fig. IV-11 shows a cutaway of this screen in a typical power plant intake. Water enters both ends of a rotating cylinder and exits through the screened periphery. The horizontal axle is supported on both ends providing a balanced design which allows the use of very large cylinders. Diameters up to 65 ft (19.8 m) have been installed and diameters in the 40 and 50 ft (12.2 and 15.2 m) range are common. It can be seen that the use of these screens results in very large supporting intake structures as evidenced in Fig. IV-11. Debris is removed by jets at the top of the screen mesh travel as noted above. of the three types of horizontal axis screens and is limited to relatively small water flows. It is offered by at least one U.S. manufacturer as well as European manufacturers. The face of the rotating disk is covered by mesh. The disk axle is cantilevered from one support. The screen is set at right angles to the waterway and the water moves through it in a straight line’ to the clean water channel behind (as contrasted with the drum screens which require a change in water direction). 44 WATER INTAKE STRUCTURES DEUHIS REMOVAL SYSTEM a FY Ly ROTATION 7 SECTION ON AA SCREENED WATER i | DIRECTION OF FLOW UNSCREENLO WATER Figure 1V-9 SINGLE ENTRY ROTATING DRUM (CUP) SCREEN Courtesy of: Hawker Siddeley Brackett Ltd. Source: EPA (Ref. 27) FISH PROTECTION METHODS DE UHIS HEMOVAL SYSIER. Figure IV-10 DOUBLE ENTRY ROTATING DRUM (CUP) SCREEN Courtesy of: Hawker Siddeley Brackett Ltd. Source: EPA (Ref. 27) 45 47° HISH PROTECTION METHODS WATER INTAKE STRUCTURES 46 LIN 3A18G WeLI3973 N33YIS ASIQ ONILYLON ZL-AT aundey Sit Avads q Srovsoe NaS4OS 7sPL pur LiLessmy :40 Asaquno) AVM HONOeL WSINYOHO SCREEN STRUCTURE WITH DOUBLE ENTRY DRUM (CUP) SCREEN Courtesy of:J.Blakeborough & Sons, Ltd. Figure IV-1) 48 WATER INTAKE STRUCTURES This screen, in both standard manufactured designs and custom designs, 1s Debris is removed by jets above the i smal] U.S. water intakes, tat Much of the debris water level as described above for single axis screens. an enc may fall off and remain in the waterway, however, thus reducing the efficiency of the screen. Periodic manual removal of the debris from the water will be required. ns - The drum and disk screens described 1 One manufacturer Fish Protection Eh. above have not been designed with fish protection in mind. 7 i ci ince suggests that screen velocities be reduced by increasing the screen area, n ‘ these screens must be very large for a given amount of water flow (when compare with band type screens), there is obviously a limit to how low a design screen velocity can reasonably be used. The drums would become too large or the num- a ic i flow. ber of drums uneconomical for a given The manufacturer modified the double entry drum screen Cae for ims fish protection at the Oldbury-on-Severn Nuclear Power Station in England (8). The major change in the screens themselves was the enlargement of the trash buckets to prevent salmon smolt from jumping out and falling back to bere: impinged on the screen, These trash buckets were made eee coated ue smooth epoxy to prevent descaling of the fish and finally painted Diack suce their research indicated that the dark color induced more dormant Fish behaviors The debris disposal trough system was also modified to separate debris and fish to assure a full trough for safe return of the fish to the waterway. / A variation of the disk screen, utilizing two disk faces in an open setting, is briefly discussed under MISCELLANEOUS PHYSICAL EXCLUSION SYSTEMS. PHISH PROTECTION METHODS a FISH DIVERSION CONCEPT INTRODUCTION Diversion devices are defined as Physical structures designed to alter flow conditions at the device in such a way that fish will be guided away from the main intake water flow and diverted into a bypass. The fish are then re- turned to safety through a fish return system, Diversion devices include louvers placed at an angle to the incoming flow and angled traveling screens as shown schematically in Fig. IV-13. LOUVERS General - A louver system, Fig. IV-13A, consists of an array of evenly spaced, vertical slats (tested clear openings from 1 to 12 in. (2.5 to 30.5 cm)) aligned across a channel at a specified angle and leading to a bypass. It has been found that fish tend to orient themselves facing into a current, even if they are moving with it, in order to facilitate respiration and feeding (9). Therefore, fish cannot see obstructions or barriers downstream and they rely mainly on their other senses to guide them around obstacles. The louver system takes advantage of this behavior. As fish approach the louvers, they sense the tur- bulence created by the system and move laterally away from it (10). As they are carried downstream, their lateral movement and the current eventually direct them into a bypass and then to a collecting area where they can be re- moved by various methods as discussed in SECTION VI, FISH RETURN SYSTEMS, Biological Consider ions - Model and prototype studies and applications of louver systems have, in many cases, shown high guidance efficiency (see TABLE 1V-2) under many different experimental conditions with a variety of fish species (11). There have been cases, however, where louvers have not functioned effectively in guiding fish to a bypass (12). Further, the guidance capacity of louvers is highly dependent on the length and swimuing performance of fishes. Since eggs and early larvae are essentially nonmotile, louvers would not be expected to guide these life stages. Among later life stages, Skinner (13) has demonstrated a strony positive relationship between fish length and guidance efficiency for Striped bass (Morone saxatilis) up to 1 in. (25 wm) and for white catfish (Ictalurus catus) up to approximately 1.6 in. (40 um) in full-scale efficiency evaluations at the Delta Fish Protection Facility. Efficiencies lower than 80 percent were obtained with individuals smaller than these respective sizes. 50 WAILER INTAKE SERUCTURES ISH_ RECOVERY FISHSTEM eUnPS FISH RECOVERY SYSTEM puMPS VERTICALN LOUVERS t STANDARD TRAVELING SCREENS Ty Ou oT} TRASH BARS TRASH BARS ANGLED VERTICAL LOUVERS (SCHEMATIC ONLY) ANGLED ORIENTATION OF TRAVELING SCREENS (SCHEMATIC ONLY) B A Figure IV-13 ANGLED SCREENS AND LOUVERS King Salmon King Salmon King Salmon Atlantic Salmon Coho Salmon Coho Salmon Steelhead Steelhead Salmon Fry Striped Bass Striped Bass Striped Bass White Perch Rainbow Smelt Alewife White Catfish White Catfish Atlantic Tomcod Northern Anchovy White Croaker Queenfish Surf Perches Vin = 25.4 om 1 ft = 0.305 m FISH PROTECTION METHODS TABLE IV-2 BYPASS EFFICIENCIES OF LOUVERS FOR SEVERAL SPECIES OF FISH Approach Size of Fish Velocity .-. Cin.) 2.8-2.9 2.0-5.9 3.4 Smolt 2.4-3.4 3.4 23.4 7.6 “3.4 0.6-1.3 Yearling 0.2-4.9 Yearling 2.5-3.4 2.5-3.4 0.4-0.5 3.0-3.9 2.4-5.9 3.9-11.8 3.9-11.8 2.4-11.8 (fps) 2.13-3 5-3; 9-3. . 8-3, -0 9-3. pee es) 9-3, oI=2,, 0 53.5 .0 0 -0 2ann err em eH ee pe NDP WONG onannn Efficiency 93-97 60-100 74-8) 98-100 62-66 74-79 63-96 69 90-99 98-100 69 84 98-100 98-100 97 93-97 95-100 95-100 95-100 Reference 14 13 12 15 16 12 12 7 12 14 18 13 16 16 16 13 13 13 19 19 19 19 SI $2 WAIER INTAKE STRUCTURES Engineering Considerations in the Application of biological limitations, louvers have certain engineering features which influence their applicability. First, the louver principle was initially developed for fish diversion at such facilities as irrigation and hydroelectric projects which do not require the degree of screening necessary at power plants for con- denser protection, Therefore, in past applications, stationary louver systems have been used without great concern for debris clogging problems or the need for further screening for downstream equipment protection. Gradual cloyging of Stationary louvers over time could reduce biological effectiveness since debris acts to disturb flow patterns essential to fish guidance. Accordingly, travel- ing louver screens, such as those being installed at the San Onofre Nuclear Generating Station of the Southern California Edison Co. (further described below)(20), would be required for debris removal at an increase in equipment cost. Also, existing conventional traveling water screens would be required as a backup to the louvers to screen nondiverted organisms and debris to the level necessary for condenser protection. The result is additional installation and maintenance costs, here are only for the purpose of developing an order-of-magnitude design. For the detailed design of any major water withdrawal facility, the engineer should refer to more comprehensive references and give careful consideration to local biological and site related factors. Certain general information which can be used for preliminary louver system design was developed from data obtained from model tests undertaken for the San Onofre Station. The optimum tested louver system included an approach velocity upstream of the louver array of 2.0 fps (0.6 m/sec), louvers with 1 in. (2.54 cm) clear spacing angled normal to a louver array set at 20 degrees to the approach flow, and a bypass velocity of 2.5 fps (0.75 m/sec). The bypass must be designed The fish would not enter a bypass with turbulent flow. shows the general layout of the prototype San Onofre water Total inflow is 1,850 cfs (52.4 w?/sec.). The “louvers” are Tapered bars 2 in. x 1/4 in. (5.1 cm x for smooth flow. Fig. IV-14 passages (20). the bars of the traveling bar racks, 0.63 cm) spaced | in. (2.54 cm) clear are mounted in place of traveling screen baskets on a standard vertical traveling screen mechanism, An important feature to note is that the mechanical components used here, although combined in an unusual manner, are basically long established and proven devices which have met the criterion of mechanical reliability. FISH PROTECTION METHODS Fish Removal> Area = o 1 > o . E 9 Bar Racks (Louvers) 10i=7- Figure IV-14 LOUVER PRINCIPLE-POWER PLANT INTAKE Courtesy of: Downs and Meddock (Ref. 20) 53 54 WATER INTAKE STRUCTURES Also note the guide vanes (concrete piers) in the waterway, These were essential to proper flow distribution and direction. Extensive hydraulic model tests were required to develop the waterway design. ANGLED TRAVELING SCREENS ‘al - The angled traveling screen concept utilizes standard through-flow setting previously described and set Gen traveling screens in the “flush mounted" at an angle to the incoming flow as shown schematically in Fig. IV-13B. Elimination or modification of basket side plates will provide an uninter- en face down the line of screens to the fish by- rupted passage along the scre pass. Biological Considerations - Several studies have been conducted which indicate that an angled coarse-mesh diversion screen concept is highly effective in diverting juvenile and adult fishes to bypasses. Fine mesh could be incorporated into this system such that it would act as a collection and removal scheme for nonmotile organisms as discussed in SECTION V. The following discussion is limited to the angled screen as a diversion device for swimming fish. Several major research programs have been conducted to evaluate the poten- tial of an angled screen leading to a bypass for effectively diverting fish and thereby minimizing impingement at power plant intakes. The first evalua- tions were conducted for the Southern California Edison San Onofre Station (19)(21). In these studies 5/8-in. (16 mm) mesh screens were found to be unacceptable due to poor-to-fair guidance (0 to 70 percent) of the northern mordax), @ primary test species. Moderate-to-good guidance anchovy (Engr (60 to 90 percent) of other test species was obtained with a screen set at 45 degrees to the approach flow, an approach velocity of 2.0 fps (0.6) m/sec), and a bypass velocity of 1.5 to 4.0 fps (0.46 to 1.22 m/sec). Higher efficiencies corresponded to higher bypass velocities. This was also the best setting for anchovies which were guided with 30 to 70 percent efficiency. The angled screen was not considered further because of the large bypass flow required to yield good guidance efficiencies in the test facility. However, design limitations at the San Onofre Station permitted only one approach velo- city 2 fps (0.61 m/sec) to be tested, this velocity being the minimum possible. Therefore, it should not be concluded from the San Onofre studies that angled screens would not be effective at other sites. It is possible that the same or other species could be effectively guided along angled screens under different conditions, particularly lower velocities and smaller screen mesh sizes. FISH PROTECTION METHODS 55 Later studies were conducted for a number of utilities operating large power plants on Lake Ontario and the Hudson River (22). In the studies with Lake Ontario species, the alewife being the primary species of concern, it was found that an angled screen set at a 25-degree orientation to the Fionise equal approach and bypass velocities ranging from 0.5 to 3.0 fps (0.15 to 0.91 m/sec) was 100 percent effective in diverting 1 to 6-in. (2.5-to 15.2-cm) = fish t ‘ 4 6-in. (15.2-cm) wide bypass under all conditions tested, including low wate: ° temperature (16). As a result of these findings, a complete diversion and " transportation system, incorporating Pipe and pumping components, was developed to return fish safely to the lake. Similar results were eotalaed (18) orien Studies with Hudson River species (striped bass, white perch, and Atlantic ° tomcod), which ranged in length from 2 to 6 in, (5.1 to 15.2 ca) Under thi same design and hydraulic conditions given above, the angled ‘ireen was fo sd to be 100 percent effective in guiding these species to a 6 in. (15 2-cm) ni bypass: Results of one week mortality studies showed that sirvival GF b; fish was greater than 96 percent (22). yess Although angled screens have not been otherwise evaluated for steam er plant screenwell application, they have been utilized at several hydrovlectets facilities for guiding upstream and downstream migrants. At the North Fork Pro- Ject on the Clackamas River in Oregon, angled traveling screens are installed a two Jecattons along a 2 mile (3.2-km) long fish ladder (23). Downstream migrants, primarily chinook (Oncorhynchus tshawytscha) and coho (0. kisutch) salmon and steelhead trout (Salmo gairdneri), enter the fish ladder at th North Fork Dam via a downstream migrant channel. From this point, the a bass either through an Open port in a gate system or can travel inar a stream where they are diverted by a set of angled screens and bypassed to oe fish lates The width of the approach channel is 10 ft (3m). The two ° traveling screens (0.14 in. (0.36-cm) mesh, 16-gauge wire cloth) are each 1) ft (3.4 m) wide and are set in tandem with a 2 ft (0.61-m) center pier between them. The screens are oriented at a 22-degree angle to the flow The average depth of water in front of the screens is 30 ft (9.1 m) This arrangenent has been found to be highly effective in diverting tous trae migrants without impingement provided that the total screen flow doe: exceed 500 cfs (14.0 m/sec). vm The second angled traveling screen installation is located just upstream f : of the fish ladder entrance, 2 miles (3.2 km) downstream from the North Fork Dam at the foot of the Cazadero Dam. This single screen is 7 ft (2.1 m) 56 WATER INTAKE STRUCTURES wide and is set at a 49-degree angle to the flow. The structure is utilized to separate downstream migrants from the ladder flow for subsequent introduc tion to a 5-mile (8-km) long pipeline. This pipeline transports the fish safely to a free-fall discharge just below the last dam in the complex, the River Mill Dam, Both angled traveling screen installations at the North Fork complex have been functioning effectively for nearly 18 years. Experience at the Mayfield Dam on the Cowlitz River in Washington further substantiates the effectiveness of angled screens in guiding fish (12). This dam is located 52 miles (83.7 km) above the confluence with the Columbia River, Since the Cowlitz is a major salmonid producing tributary, louvers were installed to bypass chinook and coho salmon, steelhead and cutthroat trout, and white fish (Prosopium williamsoni). As a result of extensive stud- ies conducted in 1964 and 1965, it was concluded that louvers spaced 2.25 in. (5.7 cm) apart and leading to an 8-in. (20.3-cm) wide bypass were not functioning satisfactorily. Therefore, several modifications were made and evaluated. It was found that increasing the bypass width, screening one-third of the louvers nearest the bypass, and increasing the bypass velocity did not improve the efficiency of the system significantly. lowever, when the louvers were completely covered by wovenwire screen of 3/8 in. (9.5 mm) clear opening, 100 percent efficiencies were achieved. Impingement of fish was noted only when the bypass was closed during the testing program. Otherwise, fish impingement was never observed when the screened louvers were lifted for examination. Tests were also conducted to determine whether fish which entered the screened louver system were injured during passage. It was found that some fish displayed signs of abrasion, However, the majority of the fish that suffered scale damage were only slightly abraded. ndations for Preliminary Angled Screen Design - The recommendations set forth here are only for the purpose of developing an order-of-magnitude design. It is apparent from the preceding discussion that many variables influence the performance of angled screens. This is also the situation with angled louvers previously discussed. for the detailed design of any major water withdrawal facility, the engineer should refer to more comprehensive references. The following recoumended preliminary design criteria was developed in the studies for the Lake Ontario and Hudson River intakes previously referenced. FISH PROTECTION METHODS Angle of screen to the waterway: 25° Average velocity of approach in the waterway upstream of the array of screens: 1 fps (0.30 m/sec.). Ratio of screen approach velocity to bypass velocity: 1:1 Minimum width of bypass opening: 6 in. (15.2 cm). Prototype Angled Screen Facility - Figs. IV-15 and IV-16 show an actual screen well arrangement incorporating angled flush-mounted traveling screens that : was utilized in a once-through cooling system screenwell on Lake Ontario (11) The flow rate is 725 cfs (20.53 m/s). Fish entering the screenwell will ; poss through trash racks having 3-in, 47.6 cm) clear spacing and will be guided by angled screens into a 6-in. (15.2 cm) wide bypass 7 ai euisnan bypass width is considered adequate at this site since i ective during the laboratory studies Previously des- cribed and since debris loading is generally medium. Narrow bypasses are economically desirable since bypass flow increases with width at a given velo city, thereby increasing pumping costs. However, at other sites wider by- , Se a to achieve an acceptable guidance efficiency or to revent clogging, or both. in ee oe he fach bay has two screens angled at 25 degrees The screens are 10 ft (3 m) long separated by a 3-ft 3-in. (0.99-m) wide Pier. An opening, blocked by a stop gate, is also provided for a possible future traveling screen. Two dry-pit circulating water pumps will draw the flow through the screenwell. The water column depth varies from 24 to 33 ft Sy (7.32 to 10.0 m). The approach velocity will be approximately 1.0 fps (0.3) m/sec) resulting in a 0.5 fps (0. 15-m/sec) velocity at the screen face. Openings are 3/8 in. (9.5 mn) with No. 12 gage wire cloth. The angled, flush screens are i essentially a modification of through- flow screens. ae The screen mesh = ' z The modification involves setting the individual screen ets flush in the vertical plane and eliminating the end seal plates on each side of the screen to forma flush surface with the concrete piers and the by. ' “ 5 Pass (Fig. IV-5C). In order to Prevent debris from passing under and around the foot shaft of the screen, a condition that might result in jamming due to th @ absence of the seal plates, the boot section is further modified by adding : hinged metal deflector at the top of the boot loading leg thus sealing the oot area. To reduce the clearance between the screen baskets and the main f rame, an Ultrex wear bar strip is attached to the edge of the screen frame 58 WATER INTAKE STRUCTURES Figure IV-15 ANGLED TRAVELING SCREENS AT OSWEGO STEAM STATION-UNIT 6 Mussalli and Taft (1978) Courtesy of: FISH PROTECTION METHODS Figure IV-16 PHOTOGRAPH OF ANGLED SCREENS AT OSWEGO STEAM STATION-UNIT 6 Courtesy of: Niagara Mohawk Power Corporation 59 60 WATER INTAKE STRUCTURES The wear bar will also minimize frictional forces that may result during momen- tary contact of the basket frame to the wear bar. The screen will be operated intermittently for debris removel. The debris consists mainly of Cladophora, a filamentous, periphytic algae that is common in the nearshore areas of the lake. During storms this algae breaks loose in great quantities and could block the bypass. If necessary, the 6 in. (15.2 cm) wide bypass can be cleaned manually with hand rakes through an access port located in the bypass or by removing the bypass nose section for access. Clearing of the bypass can also be accomplished by backflushing the debris back onto the traveling screens for removal. The bypass flow is designed such that the ratio of the screenwel] approach velocity to the bypass entrance velocity is 1:1, a condition that yielded high diversion efficiencies in the laboratory. A jet pump provides the energy to induce the required bypass flow and to return the fish back to the lake through a pipeline. A single jet pump is adequate for transporting fish where total head losses do not exceed 7 ft (2.1m). For the installation shown in Fig. IV-15, greater lift will be required. Therefore, a secondary angled screen and jet pump was incorporated both to achieve the additional lift and to concentrate the fish into a smaller flow for return to the lake. MISCELLANEOUS DIVERSION CONCEPTS Several other diversion type screening devices have been tested or used at irrigation facilities but either have experienced mechanical problems or do not offer fish protection capabilities. These are discussed briefly below. Horizontal Traveling Screens - The horizontal traveling screen (Fig. IV-17) was extensively studied on the West Coast for a number of years. The screen rotates horizontally in the waterway with the upstream face at an angle which guides fish in a manner similar to louvers and angled screen systems. The screen is designed to guide juvenile and adult fish to a bypass without impingement and to collect fish larvae and eggs and carry them to the same bypass for removal. Experiments in a full-scale test facility in Oregon have shown that the screen is very effective in achieving this goal (24). FISH PROTECTION METHODS \ Trash Racks Downstream (not shown) Figure 1V-17 HORIZONTAL TRAVELING SCREEN Courtesy of: Envirex 61 Fish Recovery " System 62 WATER INTAKE STRUCTURES i 0 FISH PROTECTION METHODS 63 Many mechanical problems occurred during screen testing (25) which have i RIVER FLOW . delayed any further research to the present. The requirement for continuous j SPRAY JET PIPE operation at much higher speeds than vertical traveling screens has created A FOR CLEANING f TRA’ mechanical problems that have not yet been fully resolved. Debris handling can f SIGARS) also be a problem. Two specific features make application of horizontal ° Crem penneeeade traveling screens of limited practical use for power plant intakes (26). First, the screen can only be used where water depth does not exceed approximately 10 ft (3m). Secondly, the screen is generally effective only where the water level is relatively constant. Since such conditions rarely exist at power plants, particularly in coastal areas, the horizontal traveling screen is not presently developed to the point where it would effectively and reliably pro- tect organisms. Further, the screen is not presently manufactured and is not, therefore, commercially available. Revolving Drum Screens - To date, revolving drum screens of various types have not been utilized at any power plant in the United States. Many are used at irrigation facilities and some are installed for special purposes (27). Vertical drum screens, Fig. IV-18, installed along a shoreline have been proposed for use at power plant intakes. These screens are placed across an intake opening in front of the pumps. This arrangement operates well under conditions of fluctuating water levels. In theory, submerged water jets would Clean the screen during rotation; however, without a strong flushing current (such as a passing river flow) to carry removed organisms and debris, this material would simply reimpinge or possibly jam in the sealing area between the screen and the support pier. According to the U.S. EPA (27), this feature HIGH WATER “severely limits the number of locations where the screen would be effective." This screening concept has seen only limited use at water intakes and has not been developed for power plant application (27). The maximum flow rate for a screen developed by a manufacturer to date is about 5,000 gal/min (20 w/min). Since larger types have not been developed and their reliability is unknown, drum screens are not an option for once-through systems at present. One U.S. screen manufacturer offers a drum screen that surrounds the pump. This is briefly discussed under MISCELLANEOUS PHYSICAL EXCLUSION SYSTEMS. SECTION A Inclined ens - Inclined screens have also been considered for guiding fish to a bypass or collection area. Several types of inclined plane screens have been developed to date. The first is simply a conventional through-flow Figure 1V-18 REVOLVING VERTICAL DRUM SCREENS Source: EPA (Ref. 27) 64 WATER INTAKE STRUCTURES FISH PROTECTION METHODS traveling screen inclined downstream at a small angle. This is used in areas of very heavy debris loading where a conventional vertical screen would allow collected debris to fall back to the water during the wash cycle. By inclin- ing the screen up to 12 degrees, debris is held down by the force of gravity until it can be removed into a collection trough. Larger angles have been used at some installations; however, such screens have not been utilized for WATER LEVEL STOP LOG GUIDES the protection of aquatic organisms. Since screen manufacturers have not yet eS developed an inclined screen which can be completely submerged with a sub- 1s surface bypass, the present available standard screen would operate essen- i, hd tially as a conventional traveling screen with attendant impingement and & 7 removal of organisms, ' Mechanical disadvantages that have discouraged manufacturers from further | development of inclined screens for power plant use include the increase in span length and associated increase in component size and weight and the asso- ciated increase in wear of the revolving components such as bushings, bear- ings, and chains. i —- Another type of inclined screen is shown in Fig. IV-19. In this case, the 8 screen is fixed and is placed nearly parallel to the flow. An endless band 2 2 of rotating brushes sweeps debris and fish across the screen face to a sur- £55 tace collecting area. Such a screen has been used in Canada to divert ge migratory salmon from a spawning Channel with good results (28). However, FISH COLLECTION TROUGH AND there are two problems with this screen which limit its application. First, [| 7 il is necessary to maintain a constant water level in the screen area to ensure Ke [ re — that water always flows to the surface bypass. Secondly, in regions of high Sag g w debris loading, such a screen could clog quickly. pee Bayes tr The results of studies and applications of inclined plane screens to oue guia? date indicate that this device offers a potentially effective method for divert- gE iD xz ing or collecting juvenile and adult fishes. However, submerged inclined screens have not been developed for power plant application. Further, inclined SHUTTER HOIST screens have not been evaluated for the protection of fish eggs and early = w x larvae, and it is unlikely that diversion of these nonmotile organisms would zg 5 4] occur. d z & - 3 Gi FISH DETERRENCE CONCEPT © = a INTRODUCTION A number of devices have been developed which are designed to alter or take advantage of the natural behavioral pattern of fish in such a way that INCLINED PLANE SCREEN TRASH RACK Figure Iv-19 (Ref. 27) EPA Source: 66 WATER INTAKE STRUCTURES they will avoid or be deterred from an intake flow. These devices are com- monly referred to as behavioral barriers and include velocity caps, electri- cal screens, air bubble curtains, hanging chain curtains, light, sound, water jet curtains, magnetic fields, chemicals, and visual keys. The velocity cap is the only device among those listed above that has shown substantial value in deterring fish from entering an intake. Deterrence concepts apply only to organisns which can respond actively by swimming away. They are of no value in preventing the passage of organisms with little or no self-motility such as fish eggs and larvae. VELOCITY CAP FOR OFFSHORE WATER WITHDRAWALS The horizontal velocity cap over a vertical inlet shown schematically in Fig. IV-20B has been effective in reducing the number of fish drawn into this type of structure. It has been shown that fish will tend to avoid horizontal flow. They do not have a similar avoidance reaction to vertical flow that occurs without the cap as shown in Fig. IV-20A. Reductions in fish entrap- ment in west coast offshore intakes have exceeded 90 percent. The velocity cap has become virtually a standard provision for offshore intakes in both salt and fresh water. For preliminary design purposes, the geometry and inflow velocity for a typical velocity cap inlet are shown in Fig. IV-20 B. These criteria were devel- oped in model tests conducted by Southern California Edison Company (29). Those tests and tests undertaken for a New York State Utility (30) in a fresh water environment have indicated that entrapment of the several species involved did not rise markedly as the average inflow velocity was increased from 0.5 to 1.5 fps (0.15 to 0.46 m/sec). Special site specific testing on selected species may be required to develop velocity criteria for a major water intake. The velocity cap clearly reduces the entrapment of fish but does not elimi- nate it. Fish recovery facilities must be provided at the screen structure if additional fish recovery is required, A typical velocity cap design for a large offshore water intake in the ocean is shown in Fig. IV-21 (31). MISCELLANEOUS DETERRENCE CONCEPTS The following brief discussion covers those deterrent devices which have been researched but have not been successful in reducing entrapment at in- takes. FISH PROTECTION METHODS VERTICAL INFLOW \ AY ZEQN 77 VELOCITY CAP —*||—— HORIZONTAL INFLOW V=0.5-1.5 fps DIMENSIONS FROM SCHULER AND LARSON INTAKE WITH VELOCITY CAP Figure 1V-20 VELOCITY CAP INTAKE Source: Schuler (Ref. 29) 67 WATER INTAKE STRUCTURES FISH PROTECTION METHODS >) Electrical Screens - The electrical screen or barrier device consists of a graduated electrical field in the water created by successive pairs of elec- trodes charged with progressively higher voltage. Two rows of iron bars with alternate electrodes in each row with the polarity shown in Fig. IV-22 can also be used. Several problems exist with electrical barriers which limit their appli- cation at power plant intakes. First, in attempting to guide fish downstream to a bypass with an electrical field, the potential for fish fatigue can seriously reduce the effectiveness of the barrier. As fish move along the electrode array, the electric field can cause rapid fatigue thereby causing the fish to be swept through the barrier (32). A second problem is that the total body voltage is directly proportional to length, and because of this, a field strength suitable to divert smaller fish may result in injury or death to larger individuals (33), Further, field strength is very difficult to maintain in water of changing conductivity as is common in estuarine and marine locations. Therefore, a voltage set to repel fish at a selected con- ductivity could stun or kill fish as conductivity increases. Finally, elec- tric screens represent a threat to humans. HIOM.(36.4 PLAN EL(20.79 £ PIPE The successful use of electrical barriers to date has been limited to deterring upstream migrating fish such as the lamprey (34). When fatigued or stunned, the fish drift back downstream, TYPICAL VELOCITY CAP INTAKE PRECAST RINGS 2 TON RIPRAP In summary, although electric screens may have some application at cer- tain sites, a failure to solve many of the major problems inherent in the design of the screen has resulted in termination of most research directed toward deterring fish moving downstream toward an intake. Ai Figure IV-2) - Air bubble curtains, Fig. IV-23, have been used at many locations in an attempt to divert or deter the movement of fish. The success of this device has been variable and appears to be affected by such factors as species, water temperature, light intensity, water velocity, and orienta- tion of the curtain within a water body. Power plant air bubble curtains have not functioned well. This type of screen has been evaluated at the Indian Point Generating Station on the Hudson River (27), at the Quad-Cities Commonwealth Edison Company on the Mississippi River (35), at the Prairie Island Nuclear Generating Plant on the Mississippi River (36), and at the Monroe Power Plant on Lake Erie (6). Air bubble cur- PANEL I"@ BARS AT 0.3M.0.C. SECTION REMOVABLE TRASH BAR EL.(-)10.6773 Richards (Ref. 31) MS.L.EL.O | SEA BOTTOM Source: = 10 Source: WATER INTAKE STRUCTURES ELECTRODE LINE OVERHEAD ————*7 GROUND LINE RECESSED FLUSH with BOTTOM ELEV. A-A Figure IV-22 ELECTRICAL SCREENS EPA (Ref. 27) FISH PROTECTION METHODS ___ AIR BUBBLES, TYPICAL ALL NOZZLES AIR PIPE NOZZLES Source: ELEVATION Figure [V-23 AIR BUBBLE CURTAIN EPA (Ref. 27) va) 72 WATER INTAKE STRUCTURES tains were not effective at these installations. A few other tests have shown only partial success under limited conditons. Accordingly, this device can not at this time be considered an effective fish deterrent system, Hanging Chain Curtain - A typical hanging chain curtain might consist of a row of chains placed across the intake channel as shown in Fig. IV-24 (27). At one power plant on the Hudson River such a barrier was ineffective. A similar barrier tested by model was moderately successful in warm water but totally ineffective in cold water, Light - The U.S. Environmental Protection Ayency (27) states that “as far as could be determined, there are no existing intakes where a light barrier is functioning successfully. Light also has the adverse effect of attracting fish under certain circumstances and has resulted in a complete shutdown of plants." There is evidence that for some species a low intensity light attracts fish, high intensity light repels, and vice versa. Other species will show no reaction to light. Sound - Studies with sound-generating devices have yielded poor results. The feasibility of using sound to guide or deter fish passage is complicated by species specificity. Many fish species possess limited or no ability to per- ceive or distinguish sounds (poor auditory capacity). These fishes rely pri- marily on their lateral line system to distinguish near-field disturbances (37). Thus, sound may attract some species, repel some, or have no effect at all. In addition, some fish have demonstrated rapid acclimation to sound negating the effectiveness of continuous underwater sound. Water Jet tain - A water jet curtain consists of a row of vertical pipes with nozzles which produce lateral jets of water across the water current entering the intake. A typical jet curtain might include vertical pipes spaced about | ft (0.30 m) apart with nozzles (openings as small as 1/32 in. (0.8 nm)) spaced about 0.5 in. (1.3 cm) on centers as shown in Fig. IV-25. This concept has been tested in large scale test facilities (30) with only limited success as a fish deterrent. for a power plant facility, the quantity of flow required for the jet curtain may be unacceptably large. Also, the maintenance required to prevent clogging of the very small nozzles from debris and rust, especially in a marine environment, could be extensive. Visual Keys - Any object which is visible to fish can act as a visual key enabling a fish to detect movement of the object in water. Tested objects Courtesy of; FISH PROTECTION METHODS Figure IV-24 MUSsalli et al. ELEVATION HANGING CHAIN CURTAIN 73 4 WATER INTAKE STRUCTURES i WATER SURFACE f_ _— PIPE MANIFOLO eo pee SUPPLY PIPE LINE WATER JET, f TYPICAL ey aay Cpe ys es VERTICAL PIPES WITH JET NOZZLES CHANNEL SIDE WALL ELEVATION VERTICAL PIPE NOTE: VERTICAL PIPES ARE 3" OIAMETER SPACED ON 12"* CENTERS. NOZZLE HOLES ARE 1732"' DIAMETER On 172" CENTERS. SECTION A-A Figure Iv-25 WATER JET CURTAIN Courtesy of: Mussalli et al. FISH PROTECTION METHODS 7s include painted woodstrips, chains, and tree branches. Visual keys appear to be effective only under illuminated conditions in relatively clean water. However, artificial illumination can, in itself, create conditions which could attract fish to an intake. Therefore, it is believed that visual keys would be of little benefit for protecting fish at power plant intakes. amount of chemicals needed and the associated costs. The large volume of water required for cooling in once-through power plants, the possibility of chemical buildup in the ecosystem, and potential long-term environmental effects have, for the most part, kept research in this area to a minimum (38) (39). Magnetic Fields - The possible use of magnetic fields for guiding fish has received little attention. It has generally been concluded that fish do not react in any way to changes in magnetic orientation or strength. Therefore, it is not possible to consider magnetism as a potentially effective fish pro- tection device. . PHYSICAL EXCLUSION CONCEPT (PASSIVE SYSTEMS) RADIAL WELL SYSTEM This intake system is a proven design with over 40 years of successful service. Since it is essentially a filter, it offers the ultimate in pro- tection to aquatic organisms of all sizes. It requires suitable subsurface soil conditions which limit its applicability. For further discussion of the radial well concept, including design re- commendations, see SECTION V, FINE SCREENING FOR SMALL ORGANISMS. CYLINDRICAL PIPE INLETS Cylindrical pipe inlets draw water through perforations or slots in a cylindrical section placed in the waterway. A conical shape is an alterna- tive. The cylindrical screen section replaces the trash bars and traveling screens of a conventional intake and also eliminates the need for a confined inlet channel. A complete intake system utilizing a large length-to-diameter perforated pipe is shown in Fig. IV-26. A number of variations which might be considered are shown in Fig. IV-27. 16 WATER INTAKE STRUCTURES ‘SHORE LIME INTAKE ‘SCREENS ALIN. CONC. CAISSONS avin _ aver 7 L. pee (i : = EE INTAKE PIPE -_ riLing Elevation Plan Perforated Pipe Intake Schematic A Plan Typical perforated Pipe Intake B Figure 1V-26 SIMPLE PERFORATED PIPE INTAKE Courtesy of: Ranney Co. FISH PROTECTION METHODS 77 —_—— \ \ CM: TM 7 ? PLAN “B" \ \ CE IT ail PLAN "Cc" PLAN "D" OPT. CLEANING PLATFORM~ag===2 —_1_1—_1__ 1 ' t ' S| CONICAL : ALTERNATIVE = PLAN "eé" nou ELEVATION F Figure I¥-27 CONCEPTUAL CYLINDRICAL PIPE INLETS Source: Richards (Ref. 41) 78 WATER INTAKE STRUCTURES In this monograph, the term "perforated" applies to round perforations and elongated slots punched in plate (Fig. IV-28A) and to slots fabricated from profile wire (wedge shaped, flat face) illustrated in Fig. IV-28B and discussed in more detail below. A primary advantage of all variations of such intakes is the absence of a confined channel in which fish might become trapped. However, the older type illustrated in Fig. IV-26 and in Fig. IV-27A is not efficient; in that entrance velocity distribution is poor, as discussed below, Cylindrical pipe inlets have been used successfully for many years for water withdrawals up to about 100,000 gal/min (400 m/min). Larger withdrawals are still rare. The largest in the United States is a multiple unit intake installed in Lake Michigan in 1980 for the Campbel] Station of Consumers Power Company. It has a capacity of 381,000 yal/min (1524 w?/min)(40). Early cylindrical pipe inlets served specifically to screen out detritus and were not used for fish protection. Their value in reducing fish intake has been recognized, however, and modifications described below have increas- ed the fish protection effectiveness of such screens (41). Cylindrical pipe inlets may be divided into three classes as follows: 1. Simple cylindrical sections. 2. Cylindrical sections with internal modifications to equalize velo- cities through the perforations. 3. Very small opening cylindrical sections requiring special intake design to permit manual cleaning. These are discussed in SECTION V, FINE SCREENING FOR SMALL ORGANISMS. The cylindrical sections for the first two classes may be installed as shown in Fig. IV-26 or combined in a number of other configurations, some of which are shown schematically in Fig. IV-27. « The conical section, shown in Fig. IV-27, is an uncommon modification which may have some value in reducing impingement of detritus and in distribut- ing inflow. Simple Cylindrical Sections - The most comnon perforated pipe inlet presently in use is the simple intake system shown in Fig. IV-26. Although the absence of a confined channel will provide some degree of fish protection, possibly enough to meet modest criteria, the simple, high length-to-diameter ratio perforated pipe is not an efficient intake. FISH PROTECTION METHODS 719 "a" PUNCHED HOLES AND SLOTS PROFILE WIRE BACKING BAR "B" PROFILE WIRE Figure IV-28 SCREENING MEDIA FOR CYLINORICAL PIPE INLETS Source: Richards (Ref. 41) 80 WATER INTAKE STRUCTURES Some typical examples of cylindrical pipe inlets are as follows: 1. Steel company water supply on the Ohio River, 1964. Design capacity 92,000 gal/min (368 m/min). Two 48 in. (122 cm) diameter perforated pipe inlets each 40 ft (12.2 m) long. Elongated slot perforations 1/2 in. x 1-1/2 in. (12.7 mm x 38.1 0m). 2. Power company on the Susquehanna River, 1974 (42). Design capacity 50,000 gal/min (200 a3/min). Two 36-in. (91-cm) diameter perforated pipe inlets each 60 ft (18.3 m) long. Elongated slot perforations 1/2 im. X 1-1/2 in. (12.7 wm x 38.1 am) in top half of pipe only. The required length and diameter of the cylindrical pipe inlet may roughly be determined as follows: a. Select a pipe diameter. Assume an inlet velocity through the open area of the perforations. A velocity of 0.5 fps (0.15 m/sec.) through the open area 1S typical of existing intakes but could be higher or Jower (see SECTION IIT for discussion of velocities). Determine the net open area of sur- face from plate manufacturer's catalog. Commercial perforated plate may be purchased with open areas up to about 50 percent open for typi- cal 1/2-in. (12.7 mm) round or 1/2-in. (12.7 wn) wide slotted perforations. Percent open area varies with the size and configuration of perfora- tions. Profile wire can be fabricated to percentage openings of over 70 percent depending on wire size and clear opening. c. Calculate the required length of screen pipe for the pipe diameter and open area selected. Additional information on sizing of cylindrical pipe intakes is provided below and in SECTION V. The inlet velocity distribution through a “simple” cylindrical pipe inlet is poor with the highest concentration of flow going through the perforations nearest to the supply pipe. This condition is clearly illustrated in Fig. IV-29A and 29B which show distributions taken from mode tests. Existing long cylindrical pipe inlets such as those cited in the typi- cal examples can be expected to perform poorly from a velocity distribution standpoint even though they perform well as intakes. This may be significant for fish protection. FISH PROTECTION METHODS #1 To improve velocity distribution, it is advantageous to keep the length- to-diameter ratio small. A rough rule of thumb is to limit the length to the same size as the diameter. However, as discussed below, even this limited length will not produce desirably uniform inflow velocities without further modification. Fat protection from detritus, a better velocity distribution would undoubt- edly give better performance, but this has apparently not been a critical prob- lem with most existing cylindrical pipe intakes Profile wire is illustrated in Fig. IV-28B. It can be fabricated in flat or curved shapes for adaptation to any type of water screen. Strength is provided by the backing bars. Its principal advantages are as follows: 1. A flat smooth outer face which is less likely to snag debris than either punched plate or the woven wire fabric conmonly used for screening material. 2. The wedge shape wire is less likely to hold material that enters the open space as compared with a flat bar or punched perforation 3. High net open areas over 70 Percent can be achieved as compared with about 50 percent for punched plate and about 60 percent for woven wire mesh. 4. For given velocity of inflow, head losses are somewhat less than for punched plate. 5. More efficient backwashing can be achieved. Cylindric al Sections With Veloci cylindrical sections. A very uniform velocity was obtained from a mode) stud (43) when an inner perforated sleeve was inserted in the screen section : (Fig. IV-29C). A typical inner sleeve design is shown in Fig. IV-30 (43) Each of the twin screen units was designed for 12,500 gal/min (50 a3 fain). Two auch twin units were provided for a 25,000 gal/min (100 m/min) intake shai in Fig. IV-31. The uniformity of the inflow velocity is achieved by creating a head loss through restricted perforations (6% to 7% open) of the inner sleeves For this particular screen array, designed for 0.5 fps (0.15 m/sec) velocity tiboulh 7 perforations, the head loss was determined by model test to be about 0.5 ft 0. 15m). | :994n0s (€b *4ay) spueyoiy Source: (3LV1d G3HNNd) 3A997S Y3NNT HLIM LIINI AdId WIIMONTTIAI O€-AI aunbry DESIGN AVERAGE VELOCITY VELOCITY DISTRIBUTION DESIGN AVE. VELOCITY SAWALOIOULS AVENE EEE Yeo PERF. — CLOSED 33% i {cee END NTERNAL PERFORATED SLEEVE 6 107% OPEN ERAS WIRE SCR. PIPE STUB & 4. 0 Figure IV-29 VELOCITY DISTRIBUTION IN A CYLINDRICAL PIPE INLET Richards (Ref. 41) ip 8: Ho i fo EF ¢ ts : : 5 ae i 5 uot zeAeTA os oe a ® Q 3 eS sa ° 5 fe p ’ a g ; 7 a8 i i g 32 : 2 it 3 $3 SGOHLAW NOLLOALOUd HSI €8 84 WATER INTAKE STRUCTURES eens tansy Ce a ewec es = i 1 oe fans Pump StaLlion and Perforated Pipe [ntake Plan ot Perforated Pipe Intake Figure IV-31 MODIFIED PERFORATED PIPE INTAKE SYSTEM Source: Richards (Ref. 43) A simpler modification is an internal pipe extending about 40% into the screen unit as shown in Fig. IV-29D. FISH PROTECTION METHODS velocity as the perforated inner sleeve. However, it has the advantages of less internal biological fouling, easier fabrication, and less head loss. Model tests have indicated that the maximum inflow velocity through the perfor- ations will be 0.5 fps (0.15 m/sec) if the average design inflow velocity is a little less than 0.4 fps (0.12 m/sec). Tt does not produce as uniform an inflow Sections - Recent field studies have indicated 85 that for very small openings, 0.04 in. (1 mn) or less cylindrical screens can be effective and practical in reducing entrainment of siiall organisms as well as reducing impingement of large organisms. Since it is probable that frequent manual cleaning of the screen units will be necessary, the design of a suitable intake must be substantially dif- ferent from that of offshore perforated pipe inlets discussed above. The small opening cylindrical screen intake is illustrated and discussed in SECTION V, FINE SCREENING FOR SMALL ORGANISMS, General Comments On Design of Cylindrical Pipe Intakes: Ve The cylindrical pipe inlet provides several fish protection advantages over conventional intakes as follows: a. b. The cylindrical pipe inlet will not be suited to some site conditions. Water depths way be insufficient to give suitable bottom clearance and Ice, high debris concentration, potential biological fouling, high suspended sediments, and interference with full submergence of screen, There is no confined channel in which fish can be trapped. Low velocities through the perforations can be achieved with a relatively modest screen unit size. The approach velocity to the screen face drops very rapidly to negligible values a few inches from the screen face. This is illustrated in Fig. IV-32 taken from model tests for the design shown in Fig. IV-30 (43). The intake can be located well away from shore and thus away from fish concentrations. navigation may be adverse factors. In still bodies of water, as contrasted with flowing rivers, debris accumulation may be excessive and backwashing ineffective. 86 WATER INTAKE STRUCTURES PERFORATED PIPE INTAKE 133.3 MODEL TEST z ermal typical intake flow velocity protile with an intern sleeve open area of 7.2%-6. 1% and an external screen open area of 40% (INTERPRETED PROTOTYPE VALUES) Flow velocity in ft/s. Q = 25,000 GPM (U.S) —--— Q =» 12,500 GPM (U.S.) Figure 1V-32 VELOCITY OF APPROACH TO CYLINDRICAL PIPE INTAKE Source: Richards (Ref. 43) Courtesy of: LaSalle Hydraulic Laboratory OPEN such and I ventional design and has been used in several U.S. installations, both FISH PROTECTION METHODS 3. Backwashing by air blast is recommended, Compressed air held in an accumulator is released quickly into the screen unit. Air backwash- ing details are discussed in SECTION V, FINE SCREENING FOR SMALL ORGANISMS. 4. Small cylindrical pipe units such as those shown in Fig. IV-30 can be designed for fairly simple removal by divers and barge mounted hoist. These units may thus be removed for periodic maintenance or replace- ment. 5. Where water level variations are small, an access platform can be placed above the screen units as shown in Fig. IV-27F. SETTING DUAL FLOW SCREEN Traveling screens and pumps can be located in an open (“no well") setting that there is no confining structure to trap fish as shown in Figs. IV-33 87 V-34 (44). In this limited sense the open setting is similar to the cylin- drical pipe intake. The screen used for open setting is the dual flow double entry-center exit type previously described. The dual flow screen is a con- the ascending and the descending sides and flows out to the pumps through the center. In the open setting concept, the pump is attached directly to the screen, ture. likel The major advantage of this design is the absence of a confining struc- Fish can escape the screen in almost all directions and are thus less y to be impinged. However, the flow distribution associated with the standard setting shown in Fig. IV-33 is nonuniform and the available screen face is not efficiently utilized. The effective area of the screen is confined to that inmediately opposite the pump intake pipe and is thus limited. the screen baskets can be made longer to provide more area in the pump intake region, water will still enter the section of the screen nearest the pump, leavi hydra pumps ng the far end of the screen relatively ineffective. The result of these ulic features is to confine the use of such a screen to relatively small if the net screen velocity is to be kept low, say 1 fps (0.30 m/sec) or less, through the mesh, Recent studies, however, have led to modifications which significantly improve flow distribution. These modifications are shown in Fig. V-1 and are discussed in Section V, FINE SCREENING FOR SMALL ORGANISMS. Water enters Although 8B WATER INTAKE STRUCTURES oy % Bye Sg eo cya eg HP gO thie casks! Pare. sr eke en | i Figure IV-33 DUAL FLOW (DOUBLE ENTRY-SINGLE EXIT) TRAVELING SCREEN- OPEN SETTING Courtesy of: FMC Corp. Figure 1V-34 FISH PROTECTION METHODS TYPICAL DUAL FLOW SCREEN INTAKE-OPEN SETTING Source: Ray (Ref. 48) 90 WATER INTAKE STRUCTURES Although an advantage of this screen setting is the probable reduction of impingement, some impingement can be expected and a fish recovery system may be required, BARRIER NETS The barrier net is a relatively large-mesh fish net placed across the entrance of an intake channel. Although extensive information on such nets is not yet available, it appears that under the proper conditions, such a design can be effective in reducing impingement at power plants. The most important factors related to effectiveness appear to be velocity and debris. Because of the large mesh sizes used to permit effective operation without excessive clogg- ing, barrier nets are not effective for protection of eggs, larvae, or z00- plankton. At Orange and Rockland Utilities Bowline Point Generating Station on the tludson River, good results have been obtained with a barrier net placed in a V-arrangement around the intake structure (45). At this site it is pos- sible to achieve velocities which are generally well below 0.5 fps (0.15 m/sec). Also, because the intake is situated in a relatively stagnant river area, it is not subjected to torces created by river currents. The V net configuration at Bowline is shown in Fig. IV-35. Nylon mesh nets with 0.15 and 0.2 in. (3.8 and 5.1 mm) openings have been under investi- gation since the spring of 1976. Impingement monitoring and tagging studies have indicated that the nets effectively reduce impingement of white perch and striped bass, the two species evaluated. Although the plant is on a major river, clogging of the net by debris or detritus has not been a problem, At Wisconsin Public Service Corporation's J.P. Pulliam Power Plant in Green Bay, Wisconsin, 1/4 in. (6.4 um) nylon nets were placed across the plant's two intake canals on an experimental basis in 1979. The two canals are 100 and 260 ft (30.5 and 79.3 m) wide. On the basis of the encouraging results from preliminary evaluation, several modifications were made to the net support system, and permanent barrier nets were installed in the Spring of 1980. Biological studies indicate that the net has reduced impingement overall] by approximately 90 percent. It is believed that this value will approach 100 percent with minor modifications to the surface net supports. Fouling and clogging of the nets has not been a problem. It should be noted that, as at Bowline Point, velocities through the barrier nets is very low, generally less than 0.4 fps (0.12 m/sec). FISH PROTECTION METHODS 91 Ne centRaL BUOY a t CHAIN (LEAD-LINE) ~ ANCHOR ANCHOR: Figure IV-35 BARRIER NET Source: Lawler, Matusky, & Skelly (Ref. 45) 92 WATER INTAKE STRUCTURES At Detroit Edison's Monroe Plant on Lake Erie, a net was placed across the intake canal in an effort to exclude fish, primarily yellow perch and gizzard shad. Unfortunately, because of high intake velocities greater than 1.3 fps (0.40 m/sec), the net clogged with fish and collapsed. MISCELLANEOUS PHYSICAL EXCLUSION SYSTEMS meet the criteria for reliable fish protection systems or do not appear to offer significant fish protection advantages. Double Disk Screen, Open Water Setting - A variation of the disk screen previously described under MISCELLANEOUS FISH COLLECTION AND REMOVAL CONCEPTS is shown in Fig. IV-36. This variation is considerably more complex than a simple disk and is referred to by its European manufacturer as a double entry drum screen. It has the disk type faces, however, with screen mesh on the ends of the drums or cylinder. It has not been used in the United States. This screen draws water from both sides of the drum into the center where the water is picked up by pump suction, The water could also be picked up by a siphon leading to a conventional pump chamber. Figure 1V-36 shows this screen mounted in an open setting surrounded by water in a wanner similar to the dual flow no-well installation Fig. IV-33. In this setting the screen offers considerable protection to fish since fish can escape relatively easily from the area of the screen face. As with the simple disk screen, a problem may arise with debris and fish falling off the screen before it reaches the screen cleaning jets. Radial lips may improve performance in this respect, but because of the angular rotation of the lips, other problems of effective debris and fish removal will be created. ca] Drum Screen Surrounding Pump - One U.S. manufacturer offers a vertical revolving drum screen which surrounds the pump as illustrated in Fig. IV-37. Debris is washed off by internal sprays. This system would have some fish pro- tection characteristics similar to the cylindrical pipe intake. Its use is confined to relatively small pumps. The proximity of the screen to the pump bell will result in nonuniform screen velocities and relatively high maximum velocities. Its effectiveness for fish protection has not been evaluated. FISH PROTECTION METHODS 93 a IS PN RHE nrg | . ae SECTION A.A U, RUBBISH HOOD ~ RUBBISH TROUGH — ~ SYPHON PIPE — “TO PUMPS SCREENED WATER ~~ SCREEN MESH es BOTH SIDES UNSCREENED : ~ WATER $ fs Feuer x ELEVATION BB Figure IV-36 DOUBLE OISK SCREEN-OPEN WATER SETTING sources EPA (Ref. 27) Ourtesy of: Hawker Siddeley Srackett Ltd 94 WATER INTAKE STRUCTURES Figure IV-37 VERTICAL REVOLVING DRUM SCREEN Source: EPA (Ref. 27) Courtesy ot: Envirex OPEN SETTING FISH PROTECTION METHODS 95 Artificial Filter Blankets and Porous Rock Dikes - Artificial filter blankets and porous rock dikes are two physical exclusion systems which have not to date met the criterion of practicality. See SECTION V, FINE SCREENING FOR SMALL ORGANISMS for further discussion. DESIGN OF TRAVELING SCREENS INTRODUCTION Vertical traveling water screens, as illustrated in the typical intake Fig. III-1, have been and will continue to be the primary means of cleaning water entering major water withdrawal facilities. Several of the fish pro- tection features previously discussed in this chapter involve modifications of this standard equipment. The basic engineering design of traveling screens is discussed here. TRAVELING SCREEN TYPES Three types of vertical traveling screens are commercially available in the United States: a. Through-flow, Figs. III-1, IV-38A, IV-39, and IV-40. . b. Dual flow (double entry-center exit), Figs. IV-38B, IV-41, and IV-42. c. Center flow (center entry-double exit), Figs. IV-38C, IV-43, and IV-44. The path of water moving through the three types of screens is shown in Fig. 1v-38. Of these three, the through-flow screen is by far the most often used in the U.S. The other two have certain limited advantages for fish protection in special situations, as discussed below, but have not come under study in the U.S. for general screening until recently when environmental regulations called for innovative screening designs. DESIGN FEATURES COMMON TO ALL SCREENS 1. All the screens described here have screening faces made up of metal- lic or plastic mesh through which the water must pass. The mesh is mechanically rotated above water for cleaning. 2. The screen mesh is fastened to multiple small trays or baskets linked together in a continuous belt, The belt revolves with one side descending and the other side, with collected debris, ascending to the structure deck, 412 10. 12. Eisele, P.J., and Malaric, J.F., “Summary Report on the P WATER INTAKE STRUCTURES REFERENCES White, J.C. Jr. and Brehmer, M.L., “Eighteen-Month Evaluation of the Ristroph Traveling Fish Screens," Proceedings of the Third National Workshop on Entrainment and Impingewent, L.0. Jensen (Ed.), Eco- logical Analysts., Inc., Melville, WY, Feb. 1976, pp. 367-380. Mussalli, ¥.G., Taft, £.P. and Hofmann, P., “Engineering Implications of New Fish Screening Concepts," Proceedings of the Fourth National Workshop on Entrainment and Impingement, L.D. Jensen (Ed.), Ecolo- gical Analysts., Inc., Melville, NY, Chicago, Dec. 1977, pp. 367-376. Ecological Analysts, Inc., “Bowline Point Generating Station Impingement Recirculation and Survival Studies," Prepared for Orange and Rockland Utilities, Inc., Pearl River, NY, 1976. King, L.R., Hutchinson, J.B. Jr., and Huggins, T.G., “Impingement Survival Studies on White Perch, Striped Bass, and Atlantic Tomcod at Three Hudson River Power Plants," Proceedings of the Fourth National Workshop on Entrainwent and Impingement, L.D. Jensen (Ed.), Ecological Analysts, Inc., Melville, NY, Chicago, Dec. 1977, pp 217-233. Wisconsin Public Service Corporation, "J.P. Pulliam Power Plant, Fish Impingement, April 1977 - December 1977," March, 19/8, 14 p. Appendix T. Detroit Edison Company, "Progress Report on the Best Available Technology for the Monroe Power Plant," Prepared by the Detroit Edison Company for Submission to the Chief Engineer of the Michigan Water Resources Commission, February 1975. rotutype Fish Pumping Studies at the Monroe Power Plant," the Detroit Edison Co., Technical Report, 1978, 14 pp. “Report on the Smolt Rescue Equipment Installed on the Circulating Water Screening Plant at Oldbury-on-Severn," Central Electricity Board, (U.K.) Ref. SPT/GG 55. Kerr, J.E., "Studies on Fish Preservation at the Contra Custa Steam Plant of the Pacific Gas and Electric Co.," California Fish and Game Bulle~ tin No. 92, 1953. Hallock, R.J., Iselin, R.A., and Fry, D.H.J., “Efficiency Tests of the Primary Louver Systems, Tracy Fish Screen, 1966-67," Marine Resources Branch, California Department of Fish and Game, 1968. Taft, £.P., and Mussalli, ¥.G., “Angled Screens and Louvers for Diverting Fish at Power Plants," Proceedings of the American Society of Civil tngineers, Journal of the Hydraulics Division, Vol. 104, No. HYS, May, 1978, pp. 623-634 Thompson, J.S., and Paulik, G.J., “An Evaluation of Louvers and Bypass Facilities for Guiding Seaward Migrant Salmonid Past Mayfield Dam in West Washington." Washington Department of Fisheries, Olympia, Washington, 1967. 135 14, 15. 16. 7, 18. 19. 20. el; een 23, 24. FISH PROTECTION METHODS 13 Skinner, J.£., "A Functional Evaluation of a Large Louver Screen Installation and Fish Facilities Research on California Water Diversi v sion P, “ Proceed ings of the Second Workshop on Entrainment and latake Sermoniag lohns Hopkins University, Baltimore, Maryland, February 5-9, 1973 : pp. 225-249, (Edison Electric Institute and Electric Power Research Institute, EPRI Publication No. 74-049-00-5, Dec. 1974). Bates, D.W., and Vinsonhaler, R., "Use of Louvers for Guiding Fish," Trans of Au, Fish Soc. 86, 1956, pp. 39-57. Ducharme, L.J.A., “An Application of Louver Deflectors for Guiding Atlantic Sal Sal e i peleaol( a0 jar) Smolts from Power Turbines," Journal Fisheries Canada, 29, pp 1397-1404, 1972. Stone and Webster Engineering Corporation, "Studies to Alleviate Potential Fish Entrapment Problems - Final Report, Nine Mile Point Nuclear Station - Unit 2," Prepared for Ni pracisetl weet may Aga or Niagara Mohawk Power Corporation, Bates, D.W., and Jewett, S.G., Jr., "Louver Efficiency in Deflecting Down- stream Migrant Steelhead," Trans (1961). - Am. Fish Soc. 90(3), pp 336-337, Stone and Webster Engineering Corporation, “Final Report - Indian Point Flume Study," ae Aig Heaarecnaced for Consolidated Edison Company of New York, Schuler, V.J., “Experimental Studies in Guiding Marine Fishes of Southern California wit! e 5 Pes ae Screens and Louvers," Ichthyol, Assoc., Bulletin 8, Downs, D.1., and Meddock, K.R., “Design of Fish Conserving Intake System," Journal of the Power Division, AS 1008, Decenber’ 1994, ap peas Vol. 100, No. P02, Proc. Paper Schuler, V.J., and Larson, L.E., “Experimental Studies Evaluating Aspects of Fish Behavior as Parameters in the Di i r S esign of Generating § Intake Systems, Southern California Edison Company and ToNEAvetotcat Associates, Inc., Middletown, Delaware, 1974, ° Taft, E.P., Jlofmann, P. Eisele, P.J., adn Horst, T.J., “An Experimental Approach to the Design of Systems for Allevi eviating Fish Impi cet in and Proposed Power Plant Intake Structures," Veataelings or é@ Third National Workshop on Entrainment and Impingement, L.D. Jensen (Ed.), Ecological Analyst i 1976. pp aaenee: ysts, Inc., Melville, New York City, NY, February Gunsolus, R.T., and Eicher, G.J., “Evaluation of Fish Passage Facilities at the North Fork Project on the Clackamas River in Oregon," The Fish Comnission of Ori i 1950, 3p. Nelo and Portland General Electric Company, September Prentice, E.F., and Ossiander, F.J., "Fish Diversion Systems and Biological Investigation of Horizontal Traveling S “ling Screen Model VII," P, ator ite ea Entrainment and {ntake scree TEG ame D y, Baltimore, M Febri 205-214, EPRI Pubs Wo. 74-049-00.57 na CDrMaTY 5-9» 1973, pp. 4 26. are 28. 29. 30. 31. 32. 335 34. 36. Bs WATER INTAKE SERUCTURES farr, W.E., and Prentice, E.F., “Mechanical Operation of Horizontal Traveling screen Model VII," Proceedings of the Second Workshop on Entrainnent and Intake Screening, Johns Hopkins University, Baltimore, Maryland, February 9-9, 1973, pp. 215-224 (EPRI Pub, No. 74-049-00-5). Rexnord Co., “Iraveling Screens to Protect Fish in Water Intake Systems,“ Envirex, Inc., Bulletin 316-300, 1973. U.S. Environmental Protection Agency, “Development Document tor Best Technology Available for the Location, Design, Construction, and Capacity of Cooling Water Intake Structures for Minimizing Adverse Environtiental Impacts," EPA 440/1-76/015-a, 1976. Kupka, K.H., “A Downstream Migrant Diversion Screen," The Canadian Fish Culturalist, No. 37 (Sept. 1966), Schuler, F.J. and Larson, L.E., “Improved fish Protection at Intake Sys- tems," Journal of the Environmental Engineering Division, ASCE, Vol. 101, No. EE 6, Proc, paper 11756, December 1975, pp 497-910. Stone and Webster Engineering Corporation, “Studies to Alleviate Fish Entrapment at Power Plant Cooling Water Intakes, Fina) Report," Prepared for Niagara Mohawk Power Corporation and Rochester Gas and Electric Corporation, November 1976. Richards, R.1., Power Plant Circulating Water Systems - A Case Study," Short Course on the Hydraulics of Cooling Water Systems for Thermal Power Plants, Colorado State University, June 1978. Sonnichsen, J.C., Bentley, £.C., Bailey, G.F., and Nakatani, R.E., “A Review of Thermal Power Plant Intake Structure Design and Related Environmental Considerations," Hanford Engineering Development Laboratory, 1973. Mowbray, W.H., and Saila, S.B., "Millstone Point Intake Barrier Design Study," Preliminary Report, To Northeast Utilities Service Co., Hartford, Kentucky, 1973. "Sea Lamprey Control on the Great Lakes 1953-54," U.S. Fish and Wildlife Service, Special Scientific Report Fisheries No, 175, May 1956. Latvaitis, 6., Bernhard, H.F., and McDonald, D.B., “Impingement Studies at Quad-Cities Station, Mississippi Rive " Proceedings of the Third National Workshop on Entrainment and Impingement, L.D. Jensen (€d.), Ecological Analysts, Inc., Melville, New York City, NY, February 19/6, pp. 269-289. Grotbeck, L.M., “Evaluation of an Air Curtain as a Fish Deterrent Device at the Prairie Island Nuclear Generating Plant Cooling Water Intake, Northern States Power (NSP), 1975 Annual Report, Environmental Moni- toring and Ecological Studies Program, Prairie Island Nuclear Generat- ing Plant, Vol IT, pp 2,8-1 to 2.8-25, 1975. Holmes, H.B., “History, Development, aad Problems of Electric Fish Screens," Fisheries and Wildlife Service, Special Scientific Report 53, 1948. 38. 39. 40. 4l. 42. 43. 44. 45. 46. 47. 48. FISH PROTECTION METHODS 15 Bell, M.C., “Fisheries Handbook of Engineer's Requirements and Biological Criteria," U.S. Army Corps of Enginee . MEIC Nivicd Portiand: Oreqea,'1973: Pp ngineers, North Pacific Division, Mayo, R.D., James, W.T., and Congle i MDs Seals yleton, J.R., “A Rational Approact Design of Power Plants Intake Fish Screens Using both pegs califoral a Behavioral Screening Methods," Krawer, Chi crawer, Chin, i fng., Technical Reprint No. is, Septusber 1372." ve Schneider, J.A., “Offshore Intake Current Status, J.H. Campbell Plant Unit #3," Proceedings of the Passive Screer 5 i i WP Inc., Chicayo, Dec. 1975, p Meee Workshop, Johnson Division Richards, R.T., “Improved Cylindrical Pipe . Convention Atlanta, oct. Bs aeetera Peet Peagertal: SP a aly sTatred Baa el Steam Electric Station Alternate i pak be Installation,” Pennsylvania £) i - tion, Structures and Hydraulics Comittee, Winter Meeting, Feb ae Richards, R.T. and Hroncich, M.J., "Perforated Pipe Water Intake for Fish Protection," Journal of the Hyd i ivi HWY 2, February 1976, pp ge ene Be tcl Me “No-Well Traveling Water Screen," Catalogue 6940 FMC Corporation Lawler, Matusky, and Skel] i e i y Engineers, "1977 Hudson River Aquatic Studies at the bowl ine Point Generating Station," Prepsrad forierie and Rockland Utilities, Inc., Pearl River, NY, 1978. oF Mussalli, Y.G., Taft, E.P. and Hofman | : aes in, P., “Biological and Engi i pape sacra tome stn the ite Screening of Small Organisms From coat tivg kes," Proceedings of the Workshop on Larval Exclusi for Power Plant Cooling Water Intakes, Sponsored by AtGonneida tices iis Laborato A i | nase NL Publ. No, ANL/ES-66), San Diego, CA, Feb. 1978, Murray, L.S. and Jinnette, T.$., “Sur L i » T.S., "Survival of Dominant Est i mp inet ion Eley Hash Troee Lins Screens at The parnayielneeies tees i. ‘oveedings of the Workshop on Larval Exclusio Power Plant Cooling Water Intake: aun 'S, sponsored by Argon Laboratory (ANL Publ. No. ANL/ES-66), San Diego, Fe Novae on 9-87 Ray, S.S., Snipes, R.L., and Tomlj i . » RL, Janovich, D.A., "A State-Of-the- Intake Technologies," TVA PRS-16 and EPA &00/7-76-020, Oc” we = ADDITIONAL REFERENCES FROM OTHER CHAPTERS 10. SCREENING FOR ORGANISMS 143 REFERENCES Murray, L.S., and Jinnette, S., "Biological Aspects of Passavant Screening," Proc. of the Workshop on Larval Exclusion Systems for Power Plant Cooling Water Intakes, Argonne National Laboratory NUREG/CP-002, ANL/ES-66, San Diego, California, February 7 and 8, 1978, pp 79-87. Ecological Analysts, Inc., "Preliminary Investigations Into the Use of a Continuous Operating Fine-Mesh Traveling Screen to Reduce Ichthyo- plankton Entrainment at Indian Point Generating Station," Prepared for Consolidated Edison Company of New York, Inc., 1977. Toml janovich, D.A., Heuer, J. H., and Voightlander, C.W., “Investigations on the Protection of Fish Larvae at Water Intakes Using Fine Mesh Screening," Tennessee Valley Authority Tech, Note No. B22, 1977. Stone and Webster Engineering Corporation, “Larval Impingement Survival Study - Prairie Island Nuclear Generating Plant," Prepared for Northern States Power Company, Minneapolis, MN, January 1980. Skinner, J.E., "A Functional Evalution of a Large Louver Screen Installation and Fish Facilities Research on California Water Diversion Projects," In: Jensen, L.0. (Editor), proceedings of the Second Workshop on Entrainment and Intake Screening, (Edison Electric Institute and Electric Power Research Institute, EPRI publication No. 74-049-00-5, December 1974), Johns Hopkins University, Baltimore, Maryland, pp 225-249. Prentice, E.F., and Ossiander, F.J., “Fish Diversion Systems and Biological Investigation of Horizontal Traveling Screen Model VII," In: Jensen, L.0. (Editor), Proceedings of the Second Workshop on Entrainment and Intake Screening, (Edison Electric Institute and Electric Power Research In- stitute and Electric Power Research Institute, EPRI publication No. 74-049-00-5, December 1974), Johns Hopkins University, Baltimore, Maryland, pp. 205-214. Stone and Webster Engineering Corporation, “Fine Mesh Screen Portotype Study’ - Final Report - Big Bend Station - Unit 4," Prepared for Tampa Electric Company, Tampa, FL, November 1980, Taft, E.P., and Mussalli, ¥.G., “Angled Screens and Louvers for Diverting Fish at Power Plants," Proceedings of the American Society of Civil Engineers, Journal of the Hydraulics Division, Vol. 104, No. HY5, Proc. Paper 13731, May 1978, pp. 623-634. Bason, W.ll., “Practicality of Profile Wire Screen in Reducing Entrainment and Impingement," Paper presented at Workshop on Larval Exclusion Systems for Power Plant Cooling Water Intakes, Sponsored by Argonne National Laboratory (ANL Publ. No. ANL/ES-66), San Diego, California, February, 1978. Hanson, 8.N., Bason, W.H., Beitz, B.E., and Charles, K.E., "A Practical Intake Screen Which Substantially Reduces the Entrainment and Impinge- went of Early Life Stages of Fish," In: Jensen, L.D. (Ed,), Proceed- ings of Fourth National Workshop on Entrainment and Impingement, Sponsored by Ecological Analysts, Inc., Melville, NY, Chicago, Illinois, December, 1977, i44 WATER INTAKE STRUCTURES ll. Lifton, W.S., “Biological Aspects of Screen Testing on the St. Johns River Palatka, Florida," Proceedings of the Passive Intake Workshop, Johnson Division UOP, Inc., Chicago, I]linois, December 1979, pp. 87-96. 12. Gulvas, J.A., and Zeitoun, I.H., “Cylindrical Wedge - Wire Screen Investi- gations In Offshort Lake Michigan for the J. i. Campbell Plant, 1979," Proceedings of the Passive Intake Screen Workshop, Johnson Division UOP Inc., Chicago, []linois, December 1979, pp, 39-45. 13. Wiersma, J.W., Hogg, D., Eck, L.J., “Biofouling Studies in Galveston Bay - Biological Aspects," Proceedings of the Passive Screen Workshop, Johnson Division UOP Inc., Chicago, Illinois, December 1979, pp 123-136. 14. Thiele, E.W., “Biofouling Studies in Galveston Bay - Engineering Aspects," Proceedings of the Passive Screen Workshop, Johnson Division UOP, Inc., December 1979, p. 137-147. 15. Richards, R.T., “Engineering Considerations in the Use of Artificial Filter Beds," Proceedings of the Workshop on Larval Exclusion Systems for Power Plant Cooling Water Intakes, ANL/ES-66, Argonne National Laboratory, San Dieyo, California, February 1978, pp. 5-12. lo. Schroeder, B.P., and Ketschke, B.A., "Biological Aspects of Porous Dike Intake Structures," Proceedings of the Workshop on Larval Exclusion Systems of Power Plant Cooling Water Intakes, ANL/ES-66, Argonne National Laboratory, San Diego, California, August 1978, pp. 51-64. 158 9. 10. VW. 12. WATER INTAKE STRUCTURES REFERENCES Mussalli, ¥.G. and Taft, E. P. III, "Fish Return Systens," Proceedings of 25th Annual Hydraulics Division Specialty Conference, ASCE, Texas A&M University, August, 1977, pp. 288-295 Stone & Webster Engineering Corporation, "Studies to Alleviate Potential Fish Entrapment at Unit No. 6 - Oswego Steam Station," Prepared for Niagara Mohawk Power Corporation, Syracuse, NY, May, 1977. Stone & Webster Engineering Corporation, “Studies to Alleviate Potential Fish Entrapment Problems - Final Report," Niagara Mohawk Power Cor- poration, Nine Mile Point Nuclear Station - Unit 2, May, 1977 Mussalli, Y. G., Larsen, J. and Hilke, J.L., “Performance Characteristics of Peripheral Jet Pumps," Proceedings of Joint Symposium on Design and Operation of Fluid Machinery, Colorado State University, Fort Collins, Colorado, June 12-14, 1978, Volume IT, pp. 123-131. Kerr, J.£., “Studies on Fish Preservation at the Contra Costa Steam Plant of the Pacific Gas and Electric Company," State of California, Department of Fish and Game, Fish Bulletin Ho. 92, 1953. Robinson, J.B., “Effects of Passing Juvenile King Salmon Through a Pump," State of California, Department of Fish and Game, Anadromous Fisheries Administrative Keport No. 69-1, Marcy 1969, Robinson, J.B., "Effects of Passing Juvenile Steelhead and Rainbow Trout Through a Volute Pump," State of California, Department of Fish and Game, August, 1969, Detroit Edison Company, “Progress Report on the Best Available Technology for the Monroe Power Plant," (for Submission to Chief Engineer, Michigan Water Resources Commission), 1975. Bechtel Incorporated, “Report on Fish Pumps," July 23, 197). Alden Research Laboratory and Stone & Webster Engineering Corporation, “Laboratory Evaluation of Fish Portection Devices at Intakes," Prepared for Empire State Electric Energy Research Corporation, Schenectady, NY, 198]. Taft, E.P., et al., “Laboratory Evaluation of Larval Fish Impingement and Diversion Systems," Proceedings of the Workshop on Advanced Intake Technology, San Diego, CA, April 1981. Downs, D. I. and Meddock, K.R., “Design of Fish Conserving Intake System," Journal of the Power Division, ASCE, Vol. 100, No. P02, Proc, Paper 11008, Dec. 19/4, pp. 191-205. SECTION IX ADDITIONAL REFERENCES Cannon, J.B., Cada, G.F., Campbell, K.K., Lee, D.W., and Szluka, A.T., “Fish Protection at Steam-Electric Power Plants: Alternative Screening Devices," Uak Ridye National Laboratory, Oak Ridge, TN, (ORNL/TM-6472), 1979, 142 p. Jensen, Loren D. (Editor), “Proceedings of the Second Entrainment and Intake Screening Workshop,“ Held February 5-9, 1973, at Johns tlopkins Univer- sity, Baltimore, MD. Electric Power Research Institute, Palo Alto, CA, (EPRI-Pub. No. 74-049-00-5), 1974, 347 p. Jensen, Loren D. (Editor), “Third National Workshop on Entrainment and Impingement: Section 316(b) Research and Compliance," Held Februar’ >, 24, 1976, at Americana Hote), Hew York, NY, Ecological Analysts, I. Melville, NY, 1977, 425 p. Jensen, Loren 0. (Editor), “Fourth National Workshop on Entrainment and Twpingement," Held December 5, 1977 at the Hyatt Regency O'ilare Hotel, Chicago, IL. Ecological Analysts, Inc. (EA Communications), Melville, NY, 1978, 424 p. Johnson Division UOP, Incorporated, “Passive Intake Screen Workshop," Proceedings of a workshop held Necember 4 and 5, 1979, at Shearton O'ilare Motel, Chicayo, IL, Johnson Division UOP, Inc., New Brighton, MN, 1980, 184 p. Sharma, R.K. and Palmer, J.B. (Editors), “Larval Exclusion Systems for Power Plant Cooling Water Intakes," Proceedings of the Workshop held February 7-8, 1978, at Shelter Island Inn, San Diego, CA, Argonne National Laboratory, Argonne, IL (ANL/ES 66), 1978, 237 p. Ray, s/s., Snipes, R.L. and Tombjanovich, D.A., “A State-of-the-Art Report on Intake Technologies," TVA PRS-16 and EPA-600/7-76-020, October, 1976. Mussalli, T.G,, Taft, £.P., and Larsen, J., “Offshore Water Intakes Designed to Protect Fish," Proceedings of the Hydraulic Journal, ASCE, HY-11, November, 1980, pages 1085-1901. 163