i \!, !! ;,II. ': I ,f ,Ii:!: i'j:: ~' i; ~j (t I,j "hi! '1 l, I,; 'i ~I 'i J~ illI ,I' 'iIi'!' I, I" ,I: !f1,I ',/, '/11':1Ii Ii, Ij; 1!!!t\i I: \1( Ii! \' I1:,\: i' ili1'' ii:P iI"1; ;/':1III iI!IHI ji !::: , I'!;!; ! 11'1"I!~ t i1: :j I,; i: I~. !/':;!,Ii!:,,I 'i;1:i: iI '~ - , 'li- ,ES- SS/6J'2.11756DECEMBER 1975EE6JOURNAL OFTHE ENVIRONMENTALENGINEERING DIVISIONIMPROVED FISH PROTECTION AT INTAKESYSTEMSBy Victor J. Schuler' and Lory E. LarsonINTRODUCTIONA chronic and oftenserious ecological as well as operationalproblem atwoling water intake systems is the entrainment of fishes in the cooling water.In 1972,Southern California Edison Company (SCE) sponsored joint participationwith Ichthyological Associates in studies to develop methods to prevent entrain,men! at SCEoffshore intake structures and to safely remove already entrained\pccilllcns from generating stationscrr:enwells, Results are presented in detaili in Refs, 3 and 4.These studies considered fish behavioral response to levels andchanges inIclocity and direction of flow as primary design criteria for a generating stationcooling water intake system, within thelimits imposed byconstruction andI operation restraints. The research wascoincident with development of the intake'ystem for the SCESan Onofre Nuclear Generating Station(SONGS). Units: and 3, It provided considerations basic to thedevelopment of a modifieddcsign which is expectedto offer greatly increased protection to fishes,\ EXPERIMENTAL PROGRAMThe test facility consisted of aredwood flume (50 ft x6 ft x 4 ft (15,III x1.8 m x1.2 m)) into which acontrolled flow wasreleased from anintcgral circular surge tank8 ft (2.4 m)deep and 16 ft (4,9 m) in diameterI Fig,I),Water level and velocity were controlled by valves and stoplogs, Testri~hcs, which weresupplied under a contract with an independent collectorIlere species commonly observed at SCE generating station intakcs,AlthoughIIIIlIC 20+ specieswere exposed to experimental conditions, primary emphasiswas on thenorthern anchovy(Ellgraulis mordax),the queenfish(Serirll/ls palitus),N(llc,Discllssion opcn until May I,1976, To extend the closing date one month, written request must be filed with theEditor of Technical Publications, ASCE, Thispaper is part of thecopyrighted' Journal of theEnvironmental Engineering Division' Proceedings of theAmerican Society of Civil Engineers, Vol. 101, No, EE6. Decemberms,Manuscript was submitted for review forpossible publication on December 18IY74,'Fishery Biologist, Ichthyological Assocs" Inc" Middletown, Del.Assoc, Research Engr" Southern California Edison Co" Rosemead, Calif.897: I, i"I,,,',I:: :: 1.. ,I.-898DECEMBER 1975EE6the white croaker(Gellyollemus lilleatus),the walleye surfperch(HyperprosopOIIargelltium),and the shiner perch(Cymatogaster aggregata), These fishesarcsufficiently different behaviorally to exhibit a crosssection of the responserange displayed by the variousfishes that occur atSCE facilities,Detailcd- SLIDE GATEINCLINESCREEN149'ml"',SECN A, A!!O- 0'10,:.;;,"------'-FIG. 1.Surge Tank and Test FlumeFLOWFLOWFLOWfASE "\30"Y)"I // // /r!(//~ - - -13D-cml, BYPASSHOLDINGCHAMBERHOLDINGCHAMBER~-,.RG, 2,Screen Settingof900450and30" to flowFIG, 3,Louver Frame Setting at31r and300to flowdescriptions of test species' behavior under experimental conditions arc prcsclIll',!by Schuler (3).Early experiments concentrated on the back-up system to develop thehe"method of extracting fishes that had already entered thescreenwell area IIjrhthe cooling water. We firstdetermined a threshold velocity level.defined :"one below which specimens could move at will throughout thescreenwell ;\1\for a considerable period, and above which specimenswould be overwhelm,,and swept intoscreening devices, This level would be one atwhichfish,"tE6INTAKE SYSTEMS899while stilloriented in an upstream direction, would be slowly forced downstream10 theregion of guidance devices that would shuntthem into a saferegion! for ultimateremoval. The mean approach velocity optimum for this behaviorwas 2,0 fps (0,6 m Is),Several screen and louver configurations weresequentially installed in thedownstream portion of the flume to simulate various guidance systems,MixedIpecies groups offrom 500-000 specimens were used in each test.Fisheswere used onlyonce and werereplaced after each test. Evaluation of eachIcreen and louver arrangementwas based on at least fourreplicate tests ateach experimentalsetting, First, panels of 5/8-in (16,mm) mesh (as includedin SONGS designspecifications) stainless steel screens were installed at anglesof 900 (as acontrol), 450, and 300 to a flow 24 in,30 in, (610 mm- 762mm)deep and witha mean velocity of 2,0 fps (0,61 m/s) (Fig,2), Guidance atFLOWNORHAL \0 FRAMENORMAL TOFLOW\.,;--...,A' 40"I' 30"BYPASSC' 20"RG,Louver Frame Setting at200: nowand Successful Bypass Configu-: rationRG, 5,Direction and RelationshipFlows Through and Along Louver atFrame and Vane Angles, ~II screen settingswas generally poor. Even at the relativelysteep angle of1f)0anchovy impingement was in the order of 80%, and other fishes were guided,lthe bypass with only marginal success, The apparent reasonfor the inefficiencyor angled screen panels wasthe strength of the flow through the screen relative'n the guiding component along thescreen face, Dyestudies indicated that-:tcn at 300, themuch stronger component passedthrough the screens, andfl\hes impinged on, rather than guided along. thescreen panels, Air bubbles\cre tested in conjunction with the300 screen setting, but results were notIlIhstantialIy improved,, Louvers as guidance devices were thantested, These consisted of steel vanes, JiRin, x 24in, x 2in, (3,2 mm x610 mm x 50mm) assembled into six'cctions, each 2 ft (0,6 m) long, which could be joined to create different lengthsmil a variety ofangles to flow, Louver vanes in anassembled length could!i\'I,ii,,,-ii,is':~i i:!'I, ~~ ~~ I1 J"I,\ 'i ':. i(\ I:' ,'I' "J I, IlitH! ~!' III i: Ii1 iI:II! j;:1-:1'; ,1 I'I,i;'I':1', iI':: ,, 'i;.I ,:; l': I!U;i j Ii j;l:'Ii! i.:: I" j', : fj~._~uuDECEMBER 1975EE6'E6INTAKE SYSTEMS901be operated in unison, much like avenetian blind. Theassemblypermitted After determining that a frame angle of 200300 to flow resulted in superiorevaluation of frame and vane angle jointly and independently of each other. midance, the louver array wasshortened toinvestigate bypass velocity andThe first arrays consisted of louver vanes set normal to frames situated .lX'~esign aswell as holdingchamber design, The bypass channel was widened300, or 200 to the approach velocity of 2,0 fps (0,6 m/s)(Figs,:1 and 4), II '~2,5 ft (0,76 m) and the bypass velocity was adjusted to 2,5 fps (0,76 m/s)was immediately apparent that a much stronger flow componentmovedal(1n~Fig, 4),This combination resulted in guidance of from 95%-99% for anchovythe louver face toward the bypass thanwas observed with screens, and all,nd to100% for other species, almost noimpingement on the downstream louversfishes keyed to this component and guided with greater success,md the readymovement of fishesthrough the bypass, The system workedMost impingement on and penetration of the louver occurred at thedownstream,qually well inlight and darkness, '12 in,15 in, (300 mm-375 mm) immediately ahead of the bypass opening, Thi,This bypass channel incorporates a curved rather than astraight channel,occured, at least in part,because a greater proportion of flow passesIhroll)!h'T onewith abrupt changes in direction, It wasrepeatedly demonstrated thatthe downstream end of a louver array, and theprobability of a fishpassill!! 'ilhes would move throughthe channel and into the holdingchamber only ifthrough a louver increases with distance along it.Observations suggestedIha1the loss was also a function of bypass channel design andhypass velocity,Therefore, in the remainder of the louvertesting these two areas as well a'louver frame angle, vane angle, and vane spacing were considered and modifiedOptimum guidance (in the range of 93%-97%) occurred with a framean)!kof 200 to flow, At thissetting success was greater when louvervanes werenormal to frame rather than normal to flow, Dye studies indicated thataltholl)!hthe guiding component was pronounced at both vane settings, the velocity helv.'l'l'adjacent vanes was greater at the normal toflow angle. amI guidance toIhebypass suffered (Fig, 5),After determining that a frame angle of 200200 to flow resulted insuperitlrguidance, the louver array was shortened toinvestigate bypass velocity anddesign as well as holdingchamber design, The bypasschannel waswidelled Ito 2,5 ft (.77 m), and the bypassvelocity was adjusted to 2,5 fps (,77 m/sec!(Fig, 4), This combination resulted in guidance of from 95%-99% for ancholland to 100% for other species, almost no impingement on the downstream lou\'CIand the readymovement of fishes through thebypass, The system workedequally well in light and darkness,This bypass channelincorporates a curved rather than astraight challnelor one with abrupt changes indirection, It wasrepeatedly demonstratedthatfishes would move through the channel and into the holdingchamber only ifthe flow was smooth and as free from turbulence as possible, Any abrupteh:1I1!!"in direction of flow resulted in turbulence, and fishes would.uponreaehin~these points, reverse direction and swim upstream into the main flumearea,Most impingement on and penetration of the louver occurred at the downstrl':1"1 ,12 in,15 in, (305 mm-380 mm) immediately ahead of the bypassopening, Thi, ioccurred, at least in part, because a greaterproportion of flow passes Ihro".~11the downstream end of a louver array, and theprohability of a fishp;I\,illl:through a louver increaseswith distancealong it. Observationssuggested ",:"the loss was also a function of bypass channel design andbypass veln"illTherefore, in theremainder of the louver testing these two areas aswclllouver frame angle, vane angle, and vane spacing were considered andmodifiedOptimum guidance (in the range of 93%-97%) occurred with a framc :tlll'I;of ,200 to flow, At thissetting success was greater when louvervanes lIt'"normal to frame rather than normal to flow, Dye studies indicated thatallhd".~I'the guiding component was pronounced at both vane settings the volocity belll\'adjacent vanes was greater at the normal toflow angle, and guidance1(\ III;bypass suffered (Fig, 5),, ,FLOW(41-cm)1., 2, wUJ w.(,N -;=- '", ~,~,C?' 8v UJr- BAFFLE WALLELEVATORBASKET7'-, E(213-cm)UJu-L~--L:C~E:.N.-/ -' - 0" (l52-cm)" (244-cm)' 6- ~PLAN(ii2=cm)1/4" MESH~ (64-mm)io i:!, KUJ ~/1ft'SECTIONELEVATOR BASKETFIG, 6,Fish Holding Chamber Located at End of Bypass Channelhl' flow was smooth and as free fromturbulence as possible, Any abrupt change: ", direction of flow resulted in turbulence.and fishes would, upon reachingI 'hcsc points, reversedirection and swim upstream into the r.nai~ flume area,Study to this point indicated that the optimumcombination Included a m~an! 'rproach velocity of 2,0 fps (0,6 m/s), louvers with I-in, (25.4-mm) clear spacing",cled normal to frame set at200 to flow, and a curved bypass 2,5 ft (0,; wide with a through velocity of 2,5 fps (0,76 m/s), This system repeatedlycd fish to the holding chamber., !; ~,I,: i: I, !, ,, i, ii !~ ,, i;: I': i'!i~ ;1 ~! I JI i '' 'f I!:Ii OJt!j1i '! 1; ~I I ,-l,I !. ~if '!;11ti Ill ;~I1, ,,~!l' ~IIi rF IiiIi H!Ii Ili, i;:!I 1, d'i I: 'j!, i, ,i L!: Ii1 :'I ': ,,Ii: 1. ,..l,~u:.!IJI:CEMBER 1975Studies next were focused on development of a system for removal andtransferof fishes to sea, Thechamber described in Fig, 6 wasinstalled in the surgetank at the head of the flume, A 3,fps (O,9-m/s) inflow entered alongeachof the side walls, These flows swept across the screen face (preventingimpinge,ment) and, upon meeting at screen center, were diverted toward thebafflewall, This resulted in an area ofrelatively quiet water in the center ofthechamber in which fishes concentrated, and from which they seemedunwillin~or unable to depart.The chamber was fitted with a vertical traveling basket that could beloweredto the chamber bottom, All fishes introduced to the chamber at the Ift (tUO5-m)in, (lOO-mm) opening quickly gathered in thewater column over the submergedbasket and swam in a gentle milling fashion, At this position they were completely!available to the basket lift, and test groups were repeatedly raised to the surfal'with no ill effects, Fishes displayed no adverse reaction to being lifted,The outlet screen did not foul, since the flow pattern across its facekepithe screen clear of all debris.Plastic bags were introduced to thesystem in :an attempt to deliberately foul the screen, These simply rolled along thescreenface and ended up in the center of the watercolumn and were lifted tothesurface along with test fishes.Small surfperches (X 30 mm) and anchovy (X 60 mm) of the1972 year-classwere introduced to this chamber. Mortality on the screen was 0, and all specimenswere lifted in the basket. Fishes could be kept in this chamber under thedescribedflow conditions for as long as 5 days with no apparent ill effects,Fishes lifted in the prototype basket will be transferred to a gravity fedsluicewayor pipe leading to some distance offshore and isolated from the intakestructure,With these results the first part of theexperimental program wasconcludedand considered successful. Design engineers suggested that a prototypesyslel11incorporating the conditions under which we had observedmaximum guidann'and safe removal was economically feasible, Study was nextfocused ontheintake structure itself to develop amethod to minimize the number offishe~entering ,the system and which would have to be removed by anadaptation Iof the scheme just described,Experimentation with intake structure design was purposely left untilarll'rthe guidance studies were completed to meet the constructionschedule oftheSan anofre Nuclear Generating Station, Units 2 and 3, screenwell, Adescripli(\nof the prototype screenwell can befound in Ref. I.Situated somedist:1nce :offshore andisolated in an often hostile environment, intake structures mlillnecessarily be as simple as possible, With practical limits to size, configuration, ;and complexity they must, above all things, provide sufficient water for continuolI\ Iplant operation,All SCE offshore intakes have been fitted with some type of "velocity capThis practice was adopted on the basis of rather primitive buthighlysignificantexperiments in the late 1950's, These early experiments and subsequentreslllt,with actual capped structures demonstrated that fishes can better resisthorizonl;"than vertical flows, The intake of fishes atstations early fitted withvelocit\caps was reduced by as much as 90%, We hoped to determine whyandh(1I\fish react to a capped structure and to develop a design that would incorporateall possible advantages,Identical intake structures, 36 in, (910 mm) high and 30 in,(760 mm)sqll~rc,EE6 ' EE6INTAKE SYSTEMS903modeled from a prototypestructure (Fig. 7), wereinstalled in the cylindricallank at theflume head (Fig, 8), Flowthrough each structure was controlledindependently, A perforated falsebottom was installed in the tank tomaintainequal distribution ofwater to each side of the screen thatseparated the two. ,_h_hU___--_r --f!.L "1 i", "! i--------n_--..J,,'-0'- -enCAP~J~- ,""'' ," ,'" .8, -~CTI(1!!I po-ASECTION BFIG, 7.Conventionallntake Structure with Velocity Cap~~'~~RISERb-8O'M... E,.., ~IDA!I..SECTION AFIG, 8,Comparison of Identical Conventional Design Intake StructuresI \Irllctures, one of whichserved as a control, the other experimental. ThisI mangement was reversed at each experimental stage to avoid position effects,One structure wasfitted with a cap30 in, (760 mm) square, affixed to the:orners at a heightof 12in, (305 mm), The other structure wasuncovered,The intake quantity intoeach structure was equalized so that an average velocity, I, I" I, i, ': II ,i ;;; J; ;'i!:~ r' ,: : illf~! r 1,,"Ij jIII ~' III: ."; :11' iIIi: I d!il' ::ri;I,!" "lJ'i!i:::. It::j i,: 11'1 Ii!: i: 'I:,co i, ,I' :I,~U4DECEMBER 1975~~6of 2,5 fps (0,76 m/s), which is thestandard design velocity for SCEoffshoreintake structures, entered the capped structure,Equal numbers of anchovy, croaker, andsurfperches were placed ineachof the two sections, Croaker and the surfperches tended to remain at thebottom100~ 601:;;;:...~ 401.01.5 2,""1301 ""1611EXPERIMENTAL INTAKE VELOCITYFEET PER SECOND1'"/",'"6'AG, 9,Percentage of Fish Intake for VariousVelocities below 2,5 fps (76 cm/51(Average Velocity Comparing Developed New Circular Design withConventionalDesign)Co "'~(122"m'cttf'o~:i;;j:'-OC'TOCAP- '; ".,:"""- ~ '-'-,,~: -, ' 'I!:QEJ!lli.CONTRQ GATErlSH RELEASEB')JSECTiON AFIG, 10,Comparison of Conventional Design Intake Structure and T ConfigurationRectangular Horizontal Flow Structurein each section, and none was lost to eitherstructure, The ilnchovyqllickl~'grouped into schools, and as such, swam throughout the respective areas, Tho\cin the uncapped(control) section repeatedly swam over the openstrllctmc,and on each pass, those fish closest to the verticalopening were drawn down~E6INTAKE SYSTEMS905mlo the riser.These specimens were usually drawn in tail first with their bodiesin a horizontalposition and demonstrated only slight effort to escape, Attritionas at a steady rate and continued throughout each test period of15 min,Anchovy in the capped(experimental) structure also swam throughout thechamber, but they were notexposed to a vertical down thrust. As theschoolpassed the horizontalopening, specimens closest to the structure oriented tailfirst to the intakeflow and in most instances successfully resisted entrainmentand rejoined the school. Attrition to thecapped structure occurred only duringthe first fewminutes of the test period after which the survivors, as a group,\Voided the structure,Three replicate tests were done, each with 4,000 anchovydivided evenly betweenthe two chambers, Between 85%-90% more anchovywere lost to theuncapped structure than to thecapped structure, effectivelydemonstrating thatanchovy €ould bettercontend with thehorizontal flowassociated with thecapped structure than with the vertical down thrust in theuncapped structure,Both structures were then capped, and the bottom of the two testsectionswas raised byinstalling a layer of1/ 4,in, (64-mm) mesh hardware cloth at~ in, (150 mm)below the riser tops, This was to prevent species such as croakerI and surfperchesfrom remaining below, and therefore isolated from the intakearea, Water level wasmaintained at 6 in,(150 mm) above the velocity capsfor a total depth in the testareas of 24 i~, (610 mJTI)~ ,To f~cilitate, final tallyingof results, the downstream flume was fittedlengthwise with a divIder screenand the two sections(each connected to a test structure) terminated in inclinedscreens on whichentrained specimens were collected, Anchovy results werehased on thefirst \5 minof the test period, since only small losses ofthisspecies occurredafter this time span. Species other than anchovy were exposed10experimental conditions for a minimum of 4 hr before results for themweretabulated, Mean flow through the controlstructure was maintained at 2,5 fps10,76 m/s); mean experimentalflows were sequentially raised at 0,5 fps (0,m/s) increments from 0,5 fps-O fps (0,15 m/s-6 m/s), Atleast four testswere run at each intake velocitysetting,Fish loss to the experimental structure increased with velocity, Themeanpercentage of anchovyintake at the experimental incrementsrelative to lossat the 2,fps (O,76-m/s) control ranged from 6% at 0,5 fps (0.\5 m/s) to70%al 2,0 fps (0,6 m /s) (Fig, 9). Themean percentage of fishintake of otherspecies was alsocorrelated with intake velocity, Intake of croaker and surf perchesranged from 24% at1.0 fps (0,3 m/s) to 67% at 2,0 fps (0,6 m/s)(Fig. 9),rhe weakened condition of queenfish at the timeof testing made them highlysusceptible to the intake, and allwere lost within the first 30 min of testing,Point measurements in the entrance to the structuresindicated that velocityal the bottom of the opening was twice that directly beneath the velocity cap,And it was in this region of highest velocity thilt mostspecimens were lost.The maximum entrance velocity was approx 1,5 times the mean51:.velocity,, Also, as the flow enters the structure, it immediately drops into the riser, leavinglittle reaction time for thefishes, It washypothesized that a structure withequal velocities at the lip anddirectly below the cap would reduce fish intake,To create the desired uniformity in entrancevelocity and to increase thelime forreaction to the flow, the cap and lip of the riser must extend horizontallyfrom the riser body \,5 times the height of the opeining, This T configurationi ~'I,, !."1, :, ::, i, I!: ,i '1j!1, ,,).'(, ,;;j) ;:;! ;' ;Ii' ,;:ii:~ I,j'l';!I! (1~ I ojII j! ji I!1 ,I ji Ii 11! ,II It!, ~j I:W!~ I;;'' -. ,..,l..906DECEMBER 1975' OIA, TAN(/ ,4,9,m'"-0,22"1"'-""'' "-~.-;ITY CAP.. /", :'!" ~of%'"""'- ~.:.~' ,~ ~~ ~OEJM.EE6EE6INTAKE SYSTEMS907with two rather thanfour openings, extends the horizontal flow prior to the1900 turn into the riserbody, The advantageofthis configuration was demonstratedin a comparisonwith the conventional structure used in the previous test seriesIFig, 10), The velocityin the new T shaped structure was constant throughoutIhe opening, Intests in which the uniform velocity into the Tstructure was.. Pl.EX"'-ASS VElDt'TYCAP, /VIEWIN:IPeATr -so.~-~-:-:-t-,....::: ~I .'i ~,..= ~ -"""ml 12AG. 11,Comparsion of Identical T Configuration Rectangle Horizontal FlowStruc'tures.B.!\//.r- ;,~-, _nu u_n_. n n ':!ISECTION ASECTION A-AOClANSUI,:,-" '~m'' "l!~:~W:'L2i:oj(BAG. 12.Rectangular Intake StructureE1Jlli-0' DIA1fi4~,-~NSURFACE "Fr'VELOCITYCAP I:cr=' ....J:. .:"'Sl"BOWl,'::'TO gPl.AN; ~~" ., "~2~'~D':',QlA-I'.,O-mlFIG, 13,Circular Intake StructureSECTION A-AVELOCITYCAP S"""TlIRt: IS" ""'"-'SECTION AFIG. 14.Comparison of Identical Circular Intake StructuresVELOCITYCAP ST""'T"""""""'"SECTION A-AI AG, 15,Comparison of Circular Intake Structure and Conventional Design IntakeStructurethe same asthe mean velocity into the conventional (control) structure, entrain-I ment was lower at theT structure by 60%-70%,Accordingly, the T structure with uniform intake velocity was deemed superior~O theconventional capped structure, and similar Tshaped structures wereinstalled in each testsection, Sequential O,fps (0.15-m/s) increments between5 fps-O fps (0,15 m / s-6 m/ s) were tested against a constant control intake, ,,,;,II: 'I:'II', :'! .1;lnI'I !" I' I, i'II J! "fill:; iil: (, ",:' Ii:, Ii) ~ ', ii'i I';:l: "908DECEMBER 1975EE6:E6INTAKE SYSTEMSveloc!ty of 25 fps (0,76 m/s) (Fig,1.1), Here, the average velocity valueswereEXPERIMENTS EVALUATINGSOUND AS FISH DETERRENTmeaningful Since the entrance velocity was constant. Meanpercentage offishintake as compared with a 2,fps (0,76-m / s) control rangedfrom 12%atJ..Ifps (0.47 m/s) to 57% at 2,0 fps (0,6 m/s),Size and hydraulic limitations precluded a prototype structuremodeled afterour modifiedintakC( (Fig, 12), Therefore, a circular structure was consideredwhich would incorporate the same design criteria as therectangularstructurewith two openings (Fig,13), However, in a circular design, the total areadecrease~toward the center, and flow accelerates as it penetrates the structure, Thenext~ies of experiments investigated fish behavior in response to acceleratingversusuillform entrance flows,To make model dimensions as realistic as possible, two new structureswereilt, each 7 ft (2,1 m) long, and with a 30-in. (760-mm) wide rectangularopening(FIg, 14), The control velocity was a constant 1.7 fps (0,5 m/s); the experimentalvelocity accelerated over the 7-ft (2,1 m) length from 1,7 fps-9 fps (0,5 m / s-m/ s) to simulate the acceleration as the flow enters a circularstructure, Tnfacilitate observations in the elongated span a velocity cap of clearplexiglasswas installed at a height of Ift (0,305 m) above the riser. Topreventdirectlighting of the 7-ft (2,I,m) span, an additionalplywood cover wasinstalled2 ft (0,6 m) over the pJexiglass, Among 15 tests, each with 1000-500 anchovy,a maximum of 470 specimens was lost in anyone test. Equalnumbers of specimewere, lost to each structure, and there was nodifference in percentage ofentrainment. It was apparent thatacceleration did notresult in increasedentrainment.The constant flow intake structure was modified so that the flow overIheft (2,I-m) horizontal riser in each structure acceleratedsimilarly, The controlstructure intake velocity accelerated from a base of 2,5 fps (0,76 m/s), The~xperimental intake velocity base was sequentially raised, at O,fps (O,IS-m/slIncrements, from 0,5 fps-O fps (0,15 m/s-6 m/s), The observedpercentageof fish intake relative to the control rangedfrom a mean of 3% at 0,5 fpl(0,15 m/s) to 59% at 2,0 fps (0,6 m/s), These mean percentagesof entrainmentreduction are based on at least five replicates (each with 1000- J ,500 anchovllat each velocity level.During these late experiments, only limitednumbers of species otherthananchovy were available fortesting, However, for all species the percentageof fish intake curve paralleled that for anchovy, and actualvalues were even'higher,The next, and final, series of intake model testsentailed evaluating (he 7,(2,-m) acceler~ing structure arrived at in the experimental step-wiseprogression~gamst the ongl?al conventional structuremodeled after the velocitycappedIntake presently m use by SCE (Fig,15), Each structure had a meanentrance~locity of J ,7 fps (0,5 m/s), The mean percentage of fish intakein four replic:ale~with anchovy was between 30%-40% for the circular structure ascompared Iwith the conventional. Intake of croaker and surfperches was reduced to25'7r,The intake offis~es to the, circular structure relative to theconventiona!structure at the variOUs velocitytest levels isshown inFig, 9. Thesedata~ugg~st that the advantage gainedby velocities lower than 1,5 fps (0.46111/'1IS slight. Based on botheconomic andbiological considerations. a 1,fp'(0.46-m/s) entrance velocity is considered optimum,"-.., "909Moorhouse (2) reported on experiments in which fishes displayed an avoidanreaction tocertain sounds produced under water. In mid-1972, Virginia Electricmd Power Company (VEPCO)conducted preliminary testing on the use ofiOund, primarily rock music, to repel fish from the region of underwater speakers,Preliminary results suggested some success,, Based on theVEPCO results, we initiated testing of various sounds as fishdeterrents, Studies weredone at the Long BeachGenerating Station whereforebay size ((120 ft x65 it x 35ft (37 m x20 m x IIm) deep)) wasfavorable to the gradualdispersion of sound, The forebay, which islocatedin Long Beach Harbor, is open along the 120-ft (37-m) dimension, There arenoscreens or barriers to prevent fishes from entering orleaving, At presentIhe LongBeach Generating Station is not an active generating station, Therefore,there was no flowthrough the forebay and effective experimentation was possible,Tests were conducted with six speakers located separately at various depthsas well as inclose proximity to each other to maximize sound at a single location,All experimental results are based on observations bySCUBA divers, The blackperch(Embi%ca jacksoni),shiner perch, kelp perch(Brach~/ills frena/LIs),andqueenfish were the most common fishes in the forebay, Additionally, several, thousand northernanchovy were introduced,R,-?ck music, a killer whale tapeand a range of frequenciesfrom 20 cps-000 cps were played through theI Ipeakers, None elicited anobservable fe~r reactio~. The striking of a malleton partially submerged wooden planks displaced fish upto lOft (3 m) from, the point of sound origin.Sounds of metal on wood and metal on metal wererecorded on tape, However, when amplified under water the recorded sounddid not elicit a response,I These experimentssuggested that the observed reaction to live sound, wasI not elicited by tape replaybecause of the absence of a shock waveassociated, with the live sound,I A "Popper" an underwater pneumatic impact device whichcreates a shwave and is used in seismic investigations, was tested at the Long Beach facIlitylindeI' visibilityconditions of about 15 ft (4,6 m), This device did ,elicit anavoidance reaction under certain conditions,When it was cycled contmuously,most fish avoided the immediate vicinity by atleast 10 ft. (3 m)Rates of 2cycles / min- 15 cycles / minwere tested, however, no direct correlation betweenfish reaction and cycle rate hasbeen determined, Fish in open areas reacted10 the Poppermore dramatically than did fish deep within the confines of theforcbay, Generally, they fled open areasand hovered close tounderwaterstructures, Those higher in the water columndisplayed a greater response toIhe "pop" and reacted at a distance of 60 ft(18 m) from the Popper.To determine the effectiveness of the device in open water, the Popper wastested offshore at the Redondo Beach Generating Station intakestructure undervisibility conditions of10 ft-20 ft (3 m-6 m), Two sets ofobservations ,~remade; one at Plant No,I intake, and the other at Plant No, 2, The majontyof fish near the structures were surfperches; kelp bass(Paralabrax c/athratlls),and spotted sand bass(Paralabrax macula/ofasciatlls).These were seen onand around the structure, and some wereobserved actually swimming in thearea beneath the velocity cap, Together, the rip-rap and intake structure form; I; !) ;,1;; i"!;; i:' I i!!1 :IJI HIJ J 1j ~~'II :1" ,J;'Ii'ii! i! !,\ i" i:;1:~1 !; 111 ;Ii j,~ ;11 !11 ;:;, qlr I" f'+ ;!I :'I, 'i :II ;,~ ;II '910DECEMBER 1975EE611775an artificial reef, and the largest concentration of fish was around thesestructure~~ Popper was placed at the opening of the structure midwaybetweenIh~ Ivelo~lty cap and ,~ top of the riser bowl.Upon activation of thePopper,all fish located within approx12 ft (3,7 m) left theimmediate vicinity,Thostlocated on the other three sides of thestructure showed noreaction,Afterapprox 3 hr, with the device operating continuously at 6 cycles/min12 CI'des/min, a fewindividuals of the surfperches were observed approx 5f!~R~t (1,5 m-2,~ m) from the device below and away from theopening of thtIntake, No fish were everobserved swimming in theopening in which the.Popper was operating, The results were similar at both intakes, Furthertestin~ Iof this device is planned,CONCLUSIONSCoastal fishes of Southern California can besuccessfully guided from anintake ,screenwell by means of louvers and bypassed into a holdingch:Jm"er !for u~t~mate transfer, back to their natural, ~nvironment. Ab~olute andrelativevelocItIes and directIOns of flowsare critical, and an op.tlmumcombil1:Jlion 'of these is required for a successful system,~locity capped offshore intake structures offer significantly moreprotecti(1n~o fIshes than do uncapped structures, Again, direction and velocity offlolll~tO the structure are critical, and the :t range ofvelocity about the meanX must be minimized for continuous and predictable fish protection,Sound as a dependable fish deterrent stillappears of questionableIllerirHowever, a pneumatic Popper did produce sufficientstimulus to reducefi,hconcentrations within a IO-ft (3-m) radius of the device,APPENDJX.-REFERENCES1. ~wns, D, ,, and Meddock, K. R, "Engineering Application of Fish Behavior Sludir\m the Design of Intake Systems for Coastal Generating Stations" presented althrJanuary 21-, 1974, ASCE National Water ResourcesEngineering Meeting, held,,' jLos Angeles, Calif.2, Moorhouse, V, H, K., "Reactions of Fish to NoiseCanadian BioloRY(///(1 fi,l,Vol. 7, Feb" 1953, pp, 465-467,3, Schuler, V, J" "Experimental Studies in Guiding Marine Fishes of Southern Calif",n;"with Screens and LouversBulletin, Ichthyological Associates, Inc" Middle!oll"Del., Feb" 1973,4, Schuler, V, J" "Experimental Studies in the Reduction of Intake of Fishes atOff,iJI'ICIntake Structures" Report for SouthernCalifornia Edison Company, Ichthyolo~i,Associates, Inc"Middletown, Del., Apr"1974,DECEMBER 1975EE6JOURNAL OFTHE ENVIRONMENTALENGINEERING DIVISIONPHOSPHORUS MODEL OF MUSKEGONW ASTEW A TERSYSTEMDy Carl G. Enfield I and Lowell E. Leach2 A. M. ASCEIr.'TRODUCTlONThe fate of applied phosphorus is one factor that must beconsidered whendesigning oroperating a land application typewastewater treatment system,II is essential that the concentration ofthe phosphorus which enters surfacewaters be sufficiently low toavoid degradation of aquatic systems causing anaccelerated rate of eutrophication,The objecti~e herein is to predict how the. \fuskegon County land application wastewater treatment system may function. 'ith respect to the applied phosphorus based on the constraints of a mathematicalmodel, laboratorymeasurements of thekinetics ofphosphorus sorption by\fuskegon County soils, and proposed operating conditions,, S,MULATIONApPROACHA model has been developed (3) that simulatesvertical movement and sorptionof phosphorus, The basic approachevaluating system operation involves computer:malysis of thedifferential equation1('pa S,."(I)1tax111which C = theconcentration in the liquid phase, in milligrams perliter:\- the phosphorusconcentration in the solid phase, inmicrograms of P per~ral11 ofsoil;= thetime from a convenientreference point, such as theIni!i:J1 introduction of phosphorus, in hours;the average pore velocity' Nl1te,Discussion open until May I, 1976, To extend theclosing date one month,1 written request must be filedwith the Editor of Technical Publications, ASCE, Thislrer is part of thecopyrighted Journal of the Environmental EngineeringDivision,I ' Proceedings ofthe American Society of Civil Engineers, Vol. 101, No, EE6, December, 1475,Manuscript was submitted for review for possible publication on August19, 1974,(iv, Engr, , Water Quality Control Branch, Robert S, Kerr Environmental ResearchI an" V,S, Environmental Protection Agency, Ada, Okla,'Research Hydr. Engr., Water Quality Control Branch, Robert S, Kerr EnvironmentalRr~earch Lab" V,S, Environmental Protection Agency, Ada, Okla,911! :! j~ I, ,, .; !'I.: I, i