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11756 DECEMBER 1975 EE6

JOURNAL OF

THE ENVIRONMENTAL

ENGINEERING DIVISION

IMPROVED FISH PROTECTION AT INTAKE SYSTEMS

By Victor J. Schuler ' and Lory E. Larson

INTRODUCTION

A chronic and often serious ecological as well as operational problem at woling water intake systems is the entrainment of fishes in the cooling water.

In 1972, Southern California Edison Company (SCE) sponsored joint participation

with Ichthyological Associates in studies to develop methods to prevent entrain,

men! at SCE offshore intake structures and to safely remove already entrained

\pccilllcns from generating station scrr:enwells, Results are presented in detail

i in Refs, 3 and 4.

These studies considered fish behavioral response to levels and changes in Iclocity and direction of flow as primary design criteria for a generating station

cooling water intake system , within the limits imposed by construction and

I operation restraints. The research was coincident with development of the intake 'ystem for the SCE San Onofre Nuclear Generating Station (SONGS). Units : and 3, It provided considerations basic to the development of a modified dcsign which is expected to offer greatly increased protection to fishes,

\ EXPERIMENTAL PROGRAM

The test facility consisted of a redwood flume (50 ft x 6 ft x 4 ft (15, III x 1.8 m x 1.2 m)) into which a controlled flow was released from an intcgral circular surge tank 8 ft (2.4 m) deep and 16 ft (4, 9 m) in diameter

I Fig, I), Water level and velocity were controlled by valves and stoplogs, Testri~hcs , which were supplied under a contract with an independent collector Ilere species commonly observed at SCE generating station intakcs, Although IIIIlIC 20+ species were exposed to experimental conditions , primary emphasis was on the northern 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 the Editor of Technical Publications , ASCE, This paper is part of the copyrighted' Journal of the Environmental Engineering Division ' Proceedings of the American Society of Civil Engineers , Vol. 101 , No, EE6. December

ms, Manuscript was submitted for review for possible publication on December 18 IY74,

'Fishery Biologist, Ichthyological Assocs" Inc" Middletown, Del. Assoc, Research Engr" Southern California Edison Co" Rosemead , Calif.

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the white croaker (Gellyollemus lilleatus), the walleye surfperch (HyperprosopOII

argelltium), and the shiner perch (Cymatogaster aggregata) , These fishes arc

sufficiently different behaviorally to exhibit a cross section of the response

range displayed by the various fishes that occur at SCE facilities, Detailcd

- SLIDE GATE

INCLINE

SCREEN

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,

SEC N A, A

!!O - 0

'10,

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FLOW

FLOW

FLOW

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30"

Y)" I /

/ / / /

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, BYPASS

HOLDING

CHAMBER HOLDING CHAMBER~

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RG, 2, Screen Setting of 900 450 and

30" to flow

FIG, 3, Louver Frame Setting at 31r and

300 to flow

descriptions of test species' behavior under experimental conditions arc prcsclIll

,!

by Schuler (3).

Early experiments concentrated on the back-up system to develop the he"

method of extracting fishes that had already entered the screenwell area II jrhthe cooling water. We first determined a threshold velocity level. defined :"one below which specimens could move at will throughout the screenwell ;\1\

for a considerable period , and above which specimens would be overwhelm,, and swept into screening devices, This level would be one at which fish,"

tE6 INTAKE SYSTEMS 899

while still oriented in an upstream direction, would be slowly forced downstream

10 the region of guidance devices that would shunt them into a safe region ! for ultimate removal. The mean approach velocity optimum for this behavior

was 2, 0 fps (0,6 m Is),

Several screen and louver configurations were sequentially installed in the

downstream portion of the flume to simulate various guidance systems, Mixed

Ipecies groups of from 500- 000 specimens were used in each test. Fishes

were used only once and were replaced after each test. Evaluation of eachIcreen and louver arrangement was based on at least four replicate tests at

each experimental setting, First, panels of 5/8-in (16,mm) mesh (as included

in SONGS design specifications) stainless steel screens were installed at angles

of 900 (as a control), 450 , and 300 to a flow 24 in, 30 in, (610 mm- 762 mm)

deep and with a mean velocity of 2,0 fps (0,61 m/s) (Fig, 2), Guidance at

FLOW

NORHAL \0 FRAME NORMAL TO FLOW

\., ;

...,

A' 40"

I' 30"

BYPASS

C' 20"

RG, Louver Frame Setting at 200 

: now and Successful Bypass Configu-

: ration

RG, 5, Direction and Relationship Flows Through and Along Louver atFrame and Vane Angles

, ~II screen settings was generally poor. Even at the relatively steep angle of

1f)0 anchovy impingement was in the order of 80%, and other fishes were guided

,lthe bypass with only marginal success, The apparent reason for the inefficiency

or angled screen panels was the strength of the flow through the screen relative

'n the guiding component along the screen face, Dye studies indicated that

-:tcn at 300 , the much stronger component passed through the screens, andfl\hes impinged on , rather than guided along. the screen panels, Air bubbles

\cre tested in conjunction with the 300 screen setting, but results were not IlIhstantialIy improved,

, Louvers as guidance devices were than tested, These consisted of steel vanes

, J iR in, x 24 in, x 2 in, (3, 2 mm x 610 mm x 50 mm) assembled into six

'cctions , each 2 ft (0,6 m) long, which could be joined to create different lengths

mil a variety of angles to flow, Louver vanes in an assembled length could

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be operated in unison , much like a venetian blind. The assembly permitted After determining that a frame angle of 200 300 to flow resulted in superior evaluation of frame and vane angle jointly and independently of each other. midance , the louver array was shortened to investigate bypass velocity and The first arrays consisted of louver vanes set normal to frames situated .lX' ~esign as well as holding chamber design, The bypass channel was widened 300 , 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 component moved al(1n~ Fig, 4), This combination resulted in guidance of from 95%-99% for anchovy the louver face toward the bypass than was observed with screens, and all ,nd to 100% for other species, almost no impingement on the downstream louvers fishes keyed to this component and guided with greater success, 

md the ready movement of fishes through the bypass, The system worked Most impingement on and penetration of the louver occurred at the downstream ,qually well in light 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 a straight channel, occured , at least in part, because a greater proportion of flow passes Ihroll)!h 'T one with abrupt changes in direction, It was repeatedly demonstrated that the downstream end of a louver array, and the probability of a fish passill!! 'ilhes would move through the channel and into the holding chamber only if through a louver increases with distance along it. Observations suggested Iha1 the loss was also a function of bypass channel design and hypass velocity, Therefore, in the remainder of the louver testing these two areas as well a' louver frame angle , vane angle , and vane spacing were considered and modified Optimum guidance (in the range of 93%-97%) occurred with a frame an)!k of 200 to flow, At this setting success was greater when louver vanes were normal to frame rather than normal to flow, Dye studies indicated that altholl)!h the guiding component was pronounced at both vane settings, the velocity helv.'l'l'

adjacent vanes was greater at the normal to flow angle. amI guidance to Ihe bypass suffered (Fig, 5),

After determining that a frame angle of 200 200 to flow resulted in superitlr guidance , the louver array was shortened to investigate bypass velocity and

design as well as holding chamber design, The bypass channel was widelled I

to 2, 5 ft (.77 m), and the bypass velocity was adjusted to 2, 5 fps (, 77 m/sec! (Fig, 4), This combination resulted in guidance of from 95%-99% for ancholl and to 100% for other species, almost no impingement on the downstream lou\'CI

and the ready movement of fishes through the bypass, The system worked equally well in light and darkness,

This bypass channel incorporates a curved rather than a straight challnel or one with abrupt changes in direction, It was repeatedly demonstrated that fishes would move through the channel and into the holding chamber only if the flow was smooth and as free from turbulence as possible, Any abrupt eh:1I1!!"

in direction of flow resulted in turbulence , and fishes would. upon reaehin~ these points, reverse direction and swim upstream into the main flume area, 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 bypass opening, Thi, i occurred, at least in part, because a greater proportion of flow passes I hro".~11 the downstream end of a louver array, and the prohability of a fish p;I\,illl:

through a louver increases with distance along it. Observations suggested ",:" the loss was also a function of bypass channel design and bypass veln"ill Therefore , in the remainder of the louver testing these two areas as wcll 

louver frame angle, vane angle , and vane spacing were considered and modified Optimum guidance (in the range of 93%-97%) occurred with a framc :tlll'I; of , 200 to flow, At this setting success was greater when louver vanes lIt'" normal to frame rather than normal to flow, Dye studies indicated that allhd".~I' the guiding component was pronounced at both vane settings the volocity belll\'

adjacent vanes was greater at the normal to flow angle, and guidance 1(\ III; bypass suffered (Fig, 5),

, ,

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FIG, 6, Fish Holding Chamber Located at End of Bypass Channel

hl' flow was smooth and as free from turbulence as possible, Any abrupt change

, direction of flow resulted in turbulence. and fishes would , upon reaching I ' hcsc points, reverse direction and swim upstream into the r.nai~ flume area,

Study to this point indicated that the optimum combination 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 at 200 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 repeatedly

cd fish to the holding chamber.

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Studies next were focused on development of a system for removal and transfer of fishes to sea, The chamber described in Fig, 6 was installed in the surge tank at the head of the flume, A 3, fps (O, 9-m/s) inflow entered along each of the side walls, These flows swept across the screen face (preventing impinge, ment) and , upon meeting at screen center , were diverted toward the baffle wall, This resulted in an area of relatively quiet water in the center of the chamber in which fishes concentrated , and from which they seemed unwillin~ or unable to depart.

The chamber was fitted with a vertical traveling basket that could be lowered to the chamber bottom, All fishes introduced to the chamber at the Ift (tUO5-m) in, (lOO-mm) opening quickly gathered in the water column over the submerged

basket 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 face kepi the screen clear of all debris. Plastic bags were introduced to the system in : an attempt to deliberately foul the screen, These simply rolled along the 

screen face and ended up in the center of the water column and were lifted to the surface along with test fishes. 

Small surfperches (X 30 mm) and anchovy (X 60 mm) of the 1972 year-class were introduced to this chamber. Mortality on the screen was 0, and all specimens were lifted in the basket. Fishes could be kept in this chamber under the described flow conditions for as long as 5 days with no apparent ill effects,

Fishes lifted in the prototype basket will be transferred to a gravity fed sluiceway or pipe leading to some distance offshore and isolated from the intake structure, With these results the first part of the experimental program was concluded and considered successful. Design engineers suggested that a prototype syslel11 incorporating the conditions under which we had observed maximum guidann' and safe removal was economically feasible, Study was next focused on the intake structure itself to develop a method to minimize the number of fishe~ entering ,the system and which would have to be removed by an adaptation I of the scheme just described,

Experimentation with intake structure design was purposely left until arll'r the guidance studies were completed to meet the construction schedule of the San anofre Nuclear Generating Station, Units 2 and 3, screenwell, A descripli(\n of the prototype screenwell can be found in Ref. I. Situated some dist:1nce : offshore and isolated in an often hostile environment, intake structures mlill necessarily be as simple as possible, With practical limits to size , configuration, ; and complexity they must, above all things, provide sufficient water for continuolI\ I plant operation, All SCE offshore intakes have been fitted with some type of " velocity cap This practice was adopted on the basis of rather primitive but highly significant experiments in the late 1950's, These early experiments and subsequent reslllt, with actual capped structures demonstrated that fishes can better resist horizonl;" than vertical flows, The intake of fishes at stations early fitted with velocit\ caps was reduced by as much as 90%, We hoped to determine why and h(1I\ fish react to a capped structure and to develop a design that would incorporate

all possible advantages,

Identical intake structures, 36 in, (910 mm) high and 30 in, (760 mm) sqll~rc,

EE6 ' EE6 INTAKE SYSTEMS 903

modeled from a prototype structure (Fig. 7), were installed in the cylindrical

lank at the flume head (Fig, 8), Flow through each structure was controlled

independently, A perforated false bottom was installed in the tank to maintain

equal distribution of water to each side of the screen that separated the two

. ,

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FIG, 8, Comparison of Identical Conventional Design Intake Structures

I \Irllctures, one of which served as a control , the other experimental. This

I mangement was reversed at each experimental stage to avoid position effects, One structure was fitted with a cap 30 in, (760 mm) square , affixed to the

:orners at a height of 12 in, (305 mm), The other structure was uncovered,

The intake quantity into each structure was equalized so that an average velocity

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of 2, 5 fps (0, 76 m/s), which is the standard design velocity for SCE offshore intake structures , entered the capped structure,

Equal numbers of anchovy, croaker, and surfperches were placed in each of the two sections, Croaker and the surf perches tended to remain at the bottom

100

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1301 "" 1611 EXPERIMENTAL INTAKE VELOCITY

FEET PER SECOND

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AG, 9, Percentage of Fish Intake for Various Velocities below 2,5 fps (76 cm/51 (Average Velocity Comparing Developed New Circular Design with Conventional Design) 

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FIG, 10, Comparison of Conventional Design Intake Structure and T Configuration

Rectangular Horizontal Flow Structure

in each section, and none was lost to either structure, The ilnchovy qllickl~' grouped into schools, and as such , swam throughout the respective areas, Tho\c in the uncapped (control) section repeatedly swam over the open strllctmc, and on each pass , those fish closest to the vertical opening were drawn down

~E6 INTAKE SYSTEMS 905

mlo the riser. These specimens were usually drawn in tail first with their bodies

in a horizontal position and demonstrated only slight effort to escape, Attrition

as at a steady rate and continued throughout each test period of 15 min, Anchovy in the capped (experimental) structure also swam throughout the

chamber, but they were not exposed to a vertical down thrust. As the school

passed the horizontal opening, specimens closest to the structure oriented tailfirst to the intake flow and in most instances successfully resisted entrainment

and rejoined the school. Attrition to the capped structure occurred only during the first few minutes of the test period after which the survivors, as a group,

\Voided the structure, Three replicate tests were done , each with 4,000 anchovy divided evenly between the two chambers, Between 85%-90% more anchovy

were lost to the uncapped structure than to the capped structure, effectively

demonstrating that anchovy €ould better contend with the horizontal flow

associated with the capped structure than with the vertical down thrust in theuncapped structure,

Both structures were then capped , and the bottom of the two test sections

was raised by installing a layer of 1/ 4,in, (64-mm) mesh hardware cloth at

~ in, (150 mm) below the riser tops, This was to prevent species such as croaker

I and surfperches from remaining below , and therefore isolated from the intake area, Water level was maintained at 6 in, (150 mm) above the velocity caps for a total depth in the test areas of 24 i~, (610 mJTI)~ ,To f~cilitate, f inal tallying

of results , the downstream flume was fitted lengthwise with a divIder screenand the two sections (each connected to a test structure) terminated in inclinedscreens on which entrained specimens were collected, Anchovy results werehased on the first \5 min of the test period, since only small losses of this

species occurred after this time span. Species other than anchovy were exposed

10 experimental conditions for a minimum of 4 hr before results for them were

tabulated, Mean flow through the control structure was maintained at 2, 5 fps

10,76 m/s); mean experimental flows were sequentially raised at 0,5 fps (0, m/s) increments from 0,5 fps- O fps (0, 15 m/s- 6 m/s), At least four tests

were run at each intake velocity setting, Fish loss to the experimental structure increased with velocity, The mean

percentage of anchovy intake at the experimental increments relative to loss

at the 2, fps (O, 76-m/s) control ranged from 6% at 0,5 fps (0. \5 m/s) to 70%

al 2,0 fps (0,6 m / s) (Fig, 9). The mean percentage of fish intake of other species was also correlated with intake velocity, Intake of croaker and surf perches

ranged from 24% at 1.0 fps (0, 3 m/s) to 67% at 2,0 fps (0,6 m/s) (Fig. 9), rhe weakened condition of queenfish at the time of testing made them highly

susceptible to the intake, and all were lost within the first 30 min of testing,

Point measurements in the entrance to the structures indicated that velocity

al the bottom of the opening was twice that directly beneath the velocity cap,And it was in this region of highest velocity thilt most specimens were lost. The maximum entrance velocity was approx 1,5 times the mean 51:. velocity, , Also, as the flow enters the structure , it immediately drops into the riser, leaving little reaction time for the fishes, It was hypothesized that a structure with

equal velocities at the lip and directly below the cap would reduce fish intake,

To create the desired uniformity in entrance velocity and to increase the

lime for reaction to the flow , the cap and lip of the riser must extend horizontally

from the riser body \, 5 times the height of the opeining, This T configuration

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EE6 EE6 INTAKE SYSTEMS 907

with two rather than four openings, extends the horizontal flow prior to the

1900 turn into the riser body, The advantage of this configuration was demonstrated

in a comparison with the conventional structure used in the previous test series

IFig, 10), The velocity in the new T shaped structure was constant throughout

Ihe opening, In tests in which the uniform velocity into the T structure was

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SECTION A-A

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FIG. 14. Comparison of Identical Circular Intake Structures

VELOCITY CAP ST""'T""""" 

SECTION A-A

I AG, 15,

Comparison of Circular Intake Structure and Conventional Design Intake

Structure

the same as the mean velocity into the conventional (control) structure, entrain- I ment was lower at the T structure by 60%-70%,

Accordingly, the T structure with uniform intake velocity was deemed superior

~O the conventional capped structure, and similar T shaped structures were

installed in each test section, Sequential O, fps (0. 15-m/s) increments between

5 fps- O fps (0, 15 m / s- 6 m/ s) were tested against a constant control intake

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908 DECEMBER 1975 EE6 :E6 INTAKE SYSTEMS veloc!ty of 2 5 fps (0,76 m/s) (Fig, 1.1), Here , the average velocity values were EXPERIMENTS EVALUATING SOUND AS FISH DETERRENT meaningful Since the entrance velocity was constant. Mean percentage of fish intake as compared with a 2, fps (0, 76-m / s) control ranged from 12% at J..I fps (0.47 m/s) to 57% at 2,0 fps (0,6 m/s), Size and hydraulic limitations precluded a prototype structure modeled after our modified intakC( (Fig, 12), Therefore , a circular structure was considered which would incorporate the same design criteria as the rectangular structure with two openings (Fig, 13), However, in a circular design, the total area decrease~ toward the center, and flow accelerates as it penetrates the structure, The next ~ies of experiments investigated fish behavior in response to accelerating 

versus uillform entrance flows,

To make model dimensions as realistic as possible , two new structures were ilt, each 7 ft (2, 1 m) long, and with a 30-in. (760-mm) wide rectangular opening (FIg, 14), The control velocity was a constant 1.7 fps (0,5 m/s); the experimental velocity 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 circular 

structure, Tn facilitate observations in the elongated span a velocity cap of clear plexiglass was installed at a height of I ft (0, 305 m) above the riser. To prevent direct lighting of the 7-ft (2, I,m) span , an additional plywood cover was installed

2 ft (0, 6 m) over the pJexiglass, Among 15 tests , each with 1 000- 500 anchovy, a maximum of 470 specimens was lost in anyone test. Equal numbers of specime were , lost to each structure, and there was no difference in percentage of entrainment. It was apparent that acceleration did not result in increased entrainment.

The constant flow intake structure was modified so that the flow over 

Ihe

ft (2, I-m) horizontal riser in each structure accelerated similarly, The control structure 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/sl Increments, from 0,5 fps- O fps (0, 15 m/s- 6 m/s), The observed percentage of fish intake relative to the control ranged from a mean of 3% at 0, 5 fpl (0, 15 m/s) to 59% at 2, 0 fps (0,6 m/s), These mean percentages of entrainment reduction are based on at least five replicates (each with 1 000- J ,500 anchovll at each velocity level. 

During these late experiments , only limited numbers of species other than anchovy were available for testing, However , for all species the percentage of fish intake curve paralleled that for anchovy, and actual values were even' higher,

The next, and final , series of intake model tests entailed evaluating (he 7, (2, -m) acceler ~ing structure arrived at in the experimental step-wise progression ~gamst the ongl?al conventional structure modeled after the velocity capped Intake presently m use by SCE (Fig, 15), Each structure had a mean entrance ~locity of J , 7 fps (0,5 m/s), The mean percentage of fish intake in four replic:ale~ with anchovy was between 30%-40% for the circular structure as compared I with the conventional. Intake of croaker and surfperches was reduced to 

25'7r, The intake of fis~es to the , circular structure relative to the conventiona! structure at the variOUs velocity test levels is shown in Fig, 9. These data ~ugg~st that the advantage gained by velocities lower than 1, 5 fps (0.46 111/'1 IS slight. Based on both economic and biological considerations . a 1, fp' (0.46-m/s) entrance velocity is considered optimum,

.., 

909

Moorhouse (2) reported on experiments in which fishes displayed an avoidan

reaction to certain sounds produced under water. In mid- 1972 , Virginia Electric

md Power Company (VEPCO) conducted preliminary testing on the use of

iOund , primarily rock music , to repel fish from the region of underwater speakers,Preliminary results suggested some success,

, Based on the VEPCO results, we initiated testing of various sounds as fish

deterrents, Studies were done at the Long Beach Generating Station whereforebay size ((120 ft x 65 it x 35 ft (37 m x 20 m x II m) deep)) was

favorable to the gradual dispersion of sound, The forebay, which is located

in Long Beach Harbor , is open along the 120-ft (37-m) dimension, There areno screens or barriers to prevent fishes from entering or leaving, At present

Ihe Long Beach Generating Station is not an active generating station, Therefore,

there was no flow through the forebay and effective experimentation was possible,

Tests were conducted with six speakers located separately at various depths

as well as in close proximity to each other to maximize sound at a single location,

All experimental results are based on observations by SCUBA divers, The black

perch (Embi% ca jacksoni), shiner perch , kelp perch (Brach ~/ills frena/LIs),and queenfish were the most common fishes in the forebay, Additionally, several

, thousand northern anchovy were introduced, R,-?ck music , a killer whale tape

and a range of frequencies from 20 cps- 000 cps were played through the I Ipeakers, None elicited an observable fe~r reactio~. The striking of a mallet

on partially submerged wooden planks displaced fish up to lOft (3 m) from

, the point of sound origin. Sounds of metal on wood and metal on metal were

recorded on tape, However, when amplified under water the recorded sound

did not elicit a response,

I These experiments suggested that the observed reaction to live sound , was I not elicited by tape replay because of the absence of a shock wave associated

, with the live sound,

I A "Popper " an underwater pneumatic impact device which creates a sh

wave and is used in seismic investigations , was tested at the Long Beach facIlity

lindeI' visibility conditions of about 15 ft (4,6 m), This device did , elicit an

avoidance reaction under certain conditions, When it was cycled contmuously,

most fish avoided the immediate vicinity by at least 10 ft. (3 m) Rates of 2

cycles / min- 15 cycles / min were tested , however, no direct correlation between

fish reaction and cycle rate has been determined, Fish in open areas reacted

10 the Popper more dramatically than did fish deep within the confines of theforcbay, Generally, they fled open areas and hovered close to underwaterstructures, Those higher in the water column displayed a greater response to

Ihe " 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 was

tested offshore at the Redondo Beach Generating Station intake structure under

visibility conditions of 10 ft-20 ft (3 m-6 m), Two sets of observations , ~remade; one at Plant No, I intake , and the other at Plant No, 2, The majonty

of 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 were observed actually swimming in thearea beneath the velocity cap, Together, the rip-rap and intake structure form

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910 DECEMBER 1975 

EE6 11775 an artificial reef, and the largest concentration of fish was around these structure~ ~ Popper was placed at the opening of the structure midway between Ih~ I velo~lty cap and , ~ top of the riser bowl. Upon activation of the Popper, all fish located within approx 12 ft (3, 7 m) left the immediate vicinity, Thost located on the other three sides of the structure showed no reaction, After approx 3 hr, with the device operating continuously at 6 cycles/min12 CI' des/min, a few individuals of the surfperches were observed approx 5 

f!~R ~t (1, 5 m-2,~ m) from the device below and away from the opening of tht Intake, No fish were ever observed swimming in the opening in which the. Popper was operating, The results were similar at both intakes, Further 

testin~ I of this device is planned, 

CONCLUSIONS

Coastal fishes of Southern California can be 

successfully guided from an intake ,screenwell by means of louvers and bypassed into a holding ch:Jm"er ! for u~t~mate transfer , back to their natural, ~nvironment. Ab~olute and relative velocItIes and directIOns of flows are critical , and an op.tlmum combil1:Jlion ' of these is required for a successful system,

~locity capped offshore intake structures offer significantly more 

protecti(1n ~o fIshes than do uncapped structures, Again, direction and velocity of 

floll l~tO the structure are critical , and the :t range of velocity about the mean X must be minimized for continuous and predictable fish protection,

Sound as a dependable fish deterrent still appears of questionable Illerir However, a pneumatic Popper did produce sufficient stimulus to reduce fi,h concentrations within a IO-ft (3-m) radius of the device,

APPENDJX.-REFERENCES

1. ~wns, D, , , and Meddock, K. R

, 

Engineering Application of Fish Behavior Sludir\ m the Design of Intake Systems for Coastal Generating Stations

" presented al thr January 21- , 1974 , ASCE National Water Resources Engineering Meeting, held 

,,

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Los Angeles , Calif. 2, Moorhouse, V, H, K.

, 

Reactions of Fish to Noise Canadian 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 Louvers Bulletin , Ichthyological Associates, Inc" Middle!oll" Del. , Feb" 1973,

4, Schuler , V, J" "Experimental Studies in the Reduction of Intake of Fishes at Off,iJI'IC Intake Structures " Report for Southern California Edison Company, Ichthyolo~i, Associates, Inc" Middletown, Del. , Apr" 1974,

DECEMBER 1975 EE6

JOURNAL OF

THE ENVIRONMENTAL

ENGINEERING DIVISION

PHOSPHORUS MODEL OF MUSKEGON

W ASTEW A TER SYSTEM

Dy Carl G. Enfield I and Lowell E. Leach 2 A. M. ASCE

Ir.'TRODUCTlON

The fate of applied phosphorus is one factor that must be considered when

designing or operating a land application type wastewater treatment system,

II is essential that the concentration of the phosphorus which enters surface

waters be sufficiently low to avoid degradation of aquatic systems causing an

accelerated 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 mathematical

model , laboratory measurements of the kinetics of phosphorus sorption by \fuskegon County soils, and proposed operating conditions,

, S,MULATION ApPROACH

A model has been developed (3) that simulates vertical movement and sorption of phosphorus, The basic approach evaluating system operation involves computer

:malysis of the differential equation 1(' pa S

,.

(I) 1t ax 

111 which C = the concentration in the liquid phase , in milligrams per liter:

\- the phosphorus concentration in the solid phase, in micrograms of P per

~ral11 of soil; = the time from a convenient reference point , such as theIni!i:J 1 introduction of phosphorus, in hours; the average pore velocity

' Nl1te, Discussion open until May I , 1976, To extend the closing date one month, 1 written request must be filed with the Editor of Technical Publications , ASCE, This lrer is part of the copyrighted Journal of the Environmental Engineering Division,

I ' Proceedings of the American Society of Civil Engineers , Vol. 101 , No, EE6, December , 1475, Manuscript was submitted for review for possible publication on August 19, 1974, (iv, Engr, , Water Quality Control Branch, Robert S, Kerr Environmental Research

I an" V,S, Environmental Protection Agency, Ada, Okla, 'Research Hydr. Engr. , Water Quality Control Branch , Robert S, Kerr Environmental Rr~earch Lab" V,S, Environmental Protection Agency, Ada, Okla,

911

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