ML19311C722

Public Watchdogs - NRC 2.206 Petition Exhibits 1-38 - Part 22

ML19311C722
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Site:	San Onofre
Issue date:	09/23/2014
From:	Public Watchdogs
To:	Division of Decommissioning, Uranium Recovery and Waste Programs
Cruz Z
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STATE OF CALIFORNIA-THE RESOURCES AGENCY DEPARTMENT OF PARKS AND RECREATION P.O. BOX 2390 SACRAMENTO 9!1811 (916) 445-8006 DEC 18 1980 Mr. Oino Scaletti Environmental Projects Division of Site, Safety, and Environmental Analysis U.S. Nuclear Regulatory Commission Washington, D.C.

20555

Dear Mr. Scaletti:

San Onofre Nuclear Generating Station, Units #2 and #3, Operating License Stage EDMUND G. B~OWN JR., Governor My staff has recently completed review of the "National Register Assessment Program of Cultural Resources of the 230 KV Transmission Line Rights-of-Way from San Onofre Nuclear Generating Station to Black Star Canyon and Santiago Substation and to Encina and Mission Valley Substation", prepared by WESTEC Services, dated September 1980.

In accordance with the provisions of the Advisory Council on Historic Preservation's Procedures set forth in 36 CFR 800, Section 106 of the National Historic Preservation Act of 1966 and the Memoranda of Agreement of October 29, 1979, I have the following comments to offer:

1.

Based on the information I have been provided, I concur that the following sites are not eligible for National Register of Historic Places: CA-Ora-419, Ora-823, Ora-786, Ora-787, Ora-700, Ora-782, Ora-784, Ora-785, Ora-832, SDi-6693, SOi-6131, SOi-5444, SOt-6136, SDi-6137, SDi-6150, SDi-6151, and SOi-6152.

2.

Sites CA-Ora-640, Ora-458, and SDi-6133 are outside the area of potential environmental impact for this undertaking.

3.

I do not concur that site CA-Ora-824 is not eligible for the National Register of Historic Places. I feel that this site may be eligible based on Bean and Vane's findings in 1979 that this site possesses a high potential for significance.

4.

I concur that the following sites are eligible for inclusion in the National Register as important components of the proposed San Joaquin Archeological District: CA-Ora-495, Ora-496, and Ora-499.

5.

The following sites have been determined eligible for inclusion in the National Register as important components of the Upper Aliso Creek Archeological District: CA-Ora-447, Ora-438, and Ora-725.

6.

The following sites should also be included as eligible properties within the Upper Aliso Creek Archeological District: CA-Ora-905, Ora-828, Ora-825, Ora-826, and Ora-827.

D-1

Mr. Oino Scaletti Page 2 D-2

7.

I concur that the following sites are eligible for inclusion in the National Register as significant components of the proposed Santiago Creek Archeological District: CA-Ora-829, Ora-830, and Ora-831.

8.

I concur that the following sites are eligible for inclusion in the National Register as significant components of the proposed Agua Hedionda Archeological District: CA-SDi-6135, SDi-6133, and SDi-6140.

9.

I also concur that the following sites are locally significant and are eligible for the National Register under Criterion "d" (36 CFR 1202.6): CA-Ora-498, SDi-4538, SDi-6130, SDi-6138, and SDi-6149.

10.

Formal determinations of eligibility for these sites and districts should be sought from the Keeper of the Register in accordance with 36 CFR 1204.

11.

I concur with the report's findings that this undertaking will have No Effect on eligible sites CA-Ora-905, Ora-828, Ora-826, Ora-827, Ora-829, and SDi-4538.

12.

I concur with the report's findings that operation and maintenance (O&M) of access roads will affect the following eligible sites:

CA-Ora-498, Ora-824, Ora-495, Ora-447, Ora-496, Ora-499, Ora-825, Ora-725, Ora-830, Ora-831, and SDi-6130. However, I feel that there will no No Adverse Effect on these resources if one of the two following conditions can be met:

a.

Access roads can be covered with a chemically inert, visually distinguishable fill within the boundaries of these sites in a manner which will preclude future ground disturbance of the cultural deposit during future O&M activities on access roads, or;

b.

O&M activities can be restricted to access roads, and the remaining research potential of surface artifacts within the provenience of existing access roads can be used to define the important factors which should be considered in determining the effects of continued disturbances as proposed in the Cultural Resource Management Plan on page 359 of the subject report.

This program should be oriented towards defining the value of research potential and the effects that various activities may have on disturbed surface sites in similar environmental contexts. The program should also be responsive to the Advisory Council's Supplementary Guidance for Treatment of Archeological Properties supporting a No Adverse Effect Determination.

D-3 Mr. Dino Scaletti Page 3

13.

The information I have been provided indicates that undisturbed cultural deposits will be affected by O&M of access roads in the vicinity of site CA-Ora-438.

However, it is my opinion that there will be No Adverse Effect if one of the two following conditions can be met:

a.

Access roads can be covered with a chemically inert, visually distinguishable fill within the boundaries of this site in a manner which will preclude future ground disturbance of the cultural deposit during future O&M activities, or;

b.

O&M activities can be restricted to access roads, and a Data Recovery Plan is implemented in accordance with the Advisory Council's Supplementary Guidance for Treatment of Archeological Properties supporting a No Adverse Effect Determination. The rationale for this recommendation is stated in the above referenced Guidance on pages 10 and 11, "An Undertaking may be taken to have no adverse effect *** if the agency is committed to a data recovery program *** if *** the property is shown to be subject to destruction and deterioration regardless of the undertaking, so the agency's action is only slightly hastening a process that is inevitable in any event. 11

14.

O&M activities and construction will have an effect on sites CA-SDi-6135, SDi-6138, SDi-6149, and SDi-6140.

However, it is my opinion that there will be No Adverse Effect on these sites if a Data Recovery Plan is implemented in accordance with the Advisory Council's Supplementary Guidance for Treatment of Archeological Properties supporting a No Adverse Effect Determination. The rationale for this recommendation is the same as that cited in Item 13.b. above.

15.

Concurrence of these determinations of effect should be sought from the Advisory Council in accordance with 36 CFR 800.4.c.

If you should have any questions, please contact Daniel Bell of my staff at (916) 322-8702.

Sincerely,

/<PV~~

Or

• Knox Me 11 on State Historic Preservation Officer Office of Historic Preservation D-63170

Mr. Dina Scaletti Page 4 cc: Mr. L. Jack Brunton D-4 Licensing and Environmental Department San Diego Gas and Electric Company P.O. Box 1831 San Diego, CA 92112 Mr. David White Southern California Edison Company P.O. Box 800 2244 Walnut Grove Avenue Rosemead, CA 91770 Ms. Lesley C. McCoy Cultural Systems Research, Inc.

8470 Via Sonoma, #32 La Jolla, CA 92037 Ms. Roxanna Phillips WESTEC Services, Inc.

3211 Fifth Avenue San Diego, CA 92103 Mr. Charles Niquette Advisory Council on Historic Preservation Lake Plaza-South, Suite 616 44 Union Boulevard Lakewood, CO 80228

APPENDIX E CALIFORNIA COASTAL COMMISSION, MARINE REVIEW COMMITTEE REPORT

T I-'

C:AUFORNIA C:OASTAL COMMISSION 631 Howard Street, Son Francisco 94105-(415) 543-8555 TO:

State Commissioners FROM:

Michael Fischer, Executive Director

SUBJECT:

Report of San Onofre Nuclear Power Plant Marine Review C0!11111ittee (For Commission consideration at theFebruary 17-19Meeting.)

summary The 1974 permit for the san onofre Nuclear Power Plant's Units 2 and 3 established a three member Marine Review Committee (MRC) to study the effects of the Plant's oooling system on ocean life and to make recommendations to the Commission.

Units 2 and 3 of the Plant are not yet operational. The MRC has submitted a report (conclusions attached) predicting affects on fish, kelp, plankton and other ocean lifo. The MRC recommends against any des.ii:gn changes to the coolin<; sustem at this time. Staff recommends the Commission take note of the MRC reco~m~~enda.tions and endorse a future monitoring program to determine actual effects on ocean life in the future after system operation. If substantial adverse effects are found, the Com-mission can impose desiqn or operational chenges or mitigation me~sures, based on MRC recommendations.

But, given MRC predictions, major syste~ design changes in the future* seem unlikely.

Background

The Commission's predecessor Coastal Zone Commission approved the construction of Units 2 and 3 of the San onofre Nuclear Generating Station (SONGS*!* on February 20, 1974 (Permit No. *183-73).

Condition B of the Permit provided for the establishment of an applicant funded Marine Review COmmittee (MRC) co~posed of an appointee of the State Commission, an appointee Of Southam california Edison OomP4ny, and an appointee of the appellants. The appellants are coordinated by Friends of the Earth.

The Condition provides for the MRC to undertake a *comprehensive and contin¢.ng study of the marine environment offshore from san onofre *** to predict, and later to measure, the effects of San onofre Units 2 and 3 on the marine environment *** " (Condition Bl).

The MRC can make recommendations to the COmmission, based on MRC studies, and the recol!lm<lnda.tions ca.r:~ include changes that the MRC believes necessary in the cooling system for Units 2 and 3. This cooling system takes in large amounts of seawater to cool the units and then discharges the he~ted water back to the ocean.

Condition B6 of the Permit states:

Should the study at any time indicate that the project will not comply with the regulatory requirements of State or Federal water quality agencies, or that substantial adverse effects on the marine environment are likely to occur, or are occurring, through the operation of Units 1, 2, and 3, the applicants shall immediately undertake such modifications to the cooling system as may reasonably be required to reduce such effects or comply with such regulatory requirements (which can be made while construction is going on and could be as extensive as requiring cooling towers if that is the reCOSllllenda.tion)

• The State C0!11111iasion shall then further condition the permit accordingly.

2 -

Thus; the Commission can impose new conditions on the cooling system only if the conditions are based on MRC recommendations and the Commission judges the conditions to be "reasonable".

New conditions can be based only on an MRC finding that "sub-stantial adverse effects on the marine environment are likely to occur, or are occuring, through the operation on Units l, 2, and 3 ****

• Since its beginning, the MRC has submitted a number of reports to the Commission.

After receiving an MRC report in mid-1979 the Commission, at its November 21, 1979 meeting, asked the MRC to take one final "best shot" at predicting effects on the marine environment prior to the start of Nuclear Regulatory Commission (NRC) hearings on the operating license for Units 2 and B.

The MRC has now submitted that report, KRC Document 80-04(1). The conclusions are attached to this staff report, and the MRC will present the conclusions to the Commission at its January 20-22 meeting.

Staff Analysis The Marine Review Coaunittee has, over the last six years, conducted monitoring and predicting studies that seem to be as comprehensive and thorough as possible given the state-of-the-art in predicting effects on the large and 'dynamic nearshore ocean environment. It is possible that the square kilo~eter offshore SONGS is the most heavily sampled and studied patch of tho ocean anywhere.

Predicting the effects of the SONGS cooling system on o~ean life has had to face a number of inherent difficulties, including: understanding the lite eycles of ocean organisms; obtaining enough samples ovar a long eno~qh time period to enable statistical analyses; devel-oping quantitative models of water flows, turbidity and population dynamics; and, most important, attempting to separate out effects or likely effects of*the cooling system from other major factors affecting ocean life, including storms, water temperature and chemistry changes, fishing, changes in nutrient levels, changes ln migratory habits, and natural population fluctuations.

Design Changes.

The MRC has needed to use models and numerous assumptions in assessing possible effects on liv.inq ocean populations.

suchexercfsescan give scenarios, but not high confidence predictions. The MRC report consequently presents a number of estimates o£ future effects on fish larvae, small shrimp, plankton, and and a kelp bed. It does not, however, state that these effects are likely or certain

~o occur, and, therefore, it does not state that "substantial advorse effects on the marine enviroment are likely to occur", as required in Condition B6 for modification of the cooling system.

The report, then,explicitly recommends against design changes in the cooling system at this time, while stating "it is possible that we have grossly underestimated tha ecological consequences of SONGS Units 1, 2, and 3" (Page 7).

The actual effects can only be determined through monitoring the ocean environment after the Units bec~me operational.

The MRC has extensive results frompre~operational sampling and data collection and will be in a position to implement a useful post-operational monitoring program.

Staff is therefore recommending the Commission endorse a continued MRC monitoring program and ask that the program design and budget be submitted to the Commission. If the MRC finds "substantial adverse effects" the Commission may still impose conditions accordingly.

Mitigation.

one such condition could involve mitigation for damage determined by the MRC.

The Commission directed the MRC to explore mitigation alternatives. This last attempt at predictions has taken up most MRC time, and the MRC report states it will recommend to the Commission which mitigation measures, in addition to artificial reefs for kelp, should be examined.

~.) Radiological~, Monitorinq.

A 1979 MRC report detailed a number of inadequacies in the radiological monitoring program in the ocean uound SONGS.

The Commission directed staff to report these inadequacies to the SOuthern california Edison co., the NUclear Regulatory Commission, and the california Department of Health Services and to pursue remedies.

SCE has since revised its radiological 1110nitoring program extensively and has submitted it to the NRC.

Both the NRC and the MRC author of the previous report are evaluating the revised program at present.

staff Recommendation Staff recommends the Collllllission adopt the following resolution:

The Commission thanks the Marine Review COmmittee for the report "Predictions of the Effects of San onofre Nuclear Generating Station and RecolDIIIIIndations", adopted unaniiiiOusly by the members of the MRC.

The Commission notes that the MRC doss not predict: at this ti1!18 that substantial adverse effects on the marine environment: are likely to occur fron the operations of the SONGS cooling system, and that the MRC recommends against system design changes at tthis tims.

However, the Commission also notes that the MRC states it may have grossly underestimated these effects.

The Commission agrees, therefore, that the MRC should conduct: a comprehensive and thorough monitoring program of the* effecta after SONGS becomes operational and requests that the MRC submit the design and cost of such a program to the Commission.

If such monitoring discovers substantial adverse effects on the marine environment, the Commission can, at that time, based on MRC recommendations, impose new conditions including design or operating changes or mitigation measures.

The Commission recog-nizes, given the MRC predicted effects of the cooling system, that future imposition ol! any major design changes to the cooling system is unlikely.

maril.le review committee November 17, 1980 Mr. Bill Ahearn california Coastal Commission 4th Floor 631 Boward Street Sen Francisco, california 94105

Dear Bill:

0/flu: (806} 961-3104 DVT.OFBIOLOclCAL SCIENCES VNIV£1WTT OF CAUFOIINIA SANTA liAIIBAliA, CA IIJ/01!

m1J@lill~JID NOV ~t 1980 CAI.IFORNIA COASTAL COMMISSION This letter formally transmits to the California Coastal Collllllisaion, under separate cover, the Marine Review Committee's predictions concsrning the effects of San Onofre Units 1, 2 and 3 upon the marine ecosyst~. The Rsport also contains a study of options snd a set of recommendations to the Collllllisaion.

These predictions and recommendations have been agreed upon unanimously &y the Committee.

The Appendices vill follow in approxi-mately two weeks.

A later report will discuss mitigation in more detail.

Yours sincerely, 62--.c.~

Rimlllon c. Fay

(/

&~

/Vt~

William W. Murdoch (Chairman}

m

~

REPOII.T OF THE lWWIE IIEVI!W COtiiiTTEE TO THE CALIFORNIA COASTAL CCHfiSSION~

PREDICTIONS OF THE En'ECTS OF SAil' ONOFRE NUCLEAA Gl!NEitATING STATION AII'D RECOMMElfDATIO!IS PAllT I:

RECOMMElfDATIOMS, PREDICTIONS, AII'D RATIONALE Marine Review Committee William W. Murdoch, Chairman University of California Byron J. Mechalas Southern California Edison Company Rimmon C. Fay Pacific Bio-Marine Labs, Inc.

MRC Document 80-04 (I)

Introduction Options and Recoaaendationa Predictions Fish

~p Hydda Pl&nkton Soft Bottom Comaunitiaa Bard Bottom Comaunitiea Rationale Fish ll:elp Mysids Plankton Soft Bottom Communities Hard Bottom Communities CONTEMTS Page 4

8 15 18 20 22 24 26 41 58 62 65 67

']; INTtlODUCTION Tbe Marine Raviev Committee waa charged, in Permit llo. 183-73 of the California Coastal Commission, to carry out "a comprehensive and continuing study of the marine envi1'0!1111e11t offshore from San Onofre * *

• to predict, end later to measure, the effects of San Onofre Units 2 and 3 on the marine environment, * *

• in a manner tbat vi11 result in the broedeat possible consideration of the effects of Units 1, 2 and 3 on the entire marine environment in the vicinity of San Onofre." Tbia Raport responds to tha charge to predict the effects of Units 2 and 3.

San Onofre Nuclear Generating Station (SONGS) Unit 1 has been opsrating since 1968.

Almost ISO billion gallons of seawater per year circulate through the Plant. Water flows in. through a sing.le intake and is discharged through a sing.le discbarge pipe.at l9°F above the intake temperature.

Tbe construction of SONGS Units 2 and 3 is virtually completed.

Each has a sing.le intake, each draWing in seawater at a rate of 830,000 gallons per minute, whith Will result in an estimated flov of allllost 700 billion gallons per year.

Each also discharges its heated effluent through a series of 63 diffuser ports set along e kilometer-long pipe that tapers from 18' to 10'-14' in diameter (Figura 1, Maps 1 and 2).

Tbis discharged water moves rapidly towards the surface, entraining and moving with it roughly 10 times its own volume of water.

As it spreads, this water mass moves various dis-tances offshore, depending upon the prevailing currents.

HRC baa measured these currents, and Southern California Edison baa produced a physical model of SONGS' water 1110vemant. l'he effects of the cooling system of Unit 1 upon the marine ecosystem were described in MB.C Annual Reports for 1978 and 1979.

l'he documented effects are reatricted to a region Within a kilometer or two of SONGS.

In seeking to predict the effecte of Units 2 and 3, HRC has looked at the loss

• of organiliiiiS taken into the intakes, the possible losses caused by water movements driven by tha diffuser plumes, and the effects of the diffusers and beat treatments on the physical environment, and hence upon the biota.

l'he predictions presented in this Report are in* moat cases close to final. Although we can and Will obtain some more information on the major parts of the ecosystem near SONGS before Units 2 and 3 begin operation, ve have obtained moat of the information it is possible to obtain with a faaa-ible axpenditure of effort. 'IIbera major uncertainties remain, further study vill not in general resolve them; they are largely an inescapable result of the t>ractical difficulties in studying real ecological systems, and of tha nature of such systems. l'ha ezceptions are kelp, where future -.rork should provide more, and :lmportant, information, and some modelling studies that have not yet been completed.

At this point, however, future -.rork on predic-tions is aimed mainly at guiding our monitoring studies.

Following this Introduction, the Report presents our recom=andations.

Tbere follows a brief statement of predictions for each major part of the cOI!ImUDity, and a more extensive Rationala, which explains how we arrived at the predictions. l'he Rationale unavoidably contains soma technical discussion, but we have tried to write it so that the reader unfamiliar With the study can follow it. Finally, a aeries of separate Appendicaa accompanies this Report.

Tbese appendices are the reports of various contractors, and

1"{1 V1 analyses (by MRC and its consultants) of a number of difficult technical issues. The Rationale refers to those Appendices, where necessary, by proj-ect, number and, if appropriate, page number.

We would like to stress two findings that have general importance for management of and planning for nearshore coastal waters in California.

First, we reiterate a previous conclusion that, in open coastal situations, a diffuser design is likely to he ecologically more damaging than a single point discharge, even though the latter would ~alate present State thermal discharge standards.

Second, we have recently obtained evidence that the early (larval) stages of nearshore sport and commercial fish species (e.g. bass, halibut) are particularly sparse very close to shore, while the larvae of fodder fish species are abundant tight into shallow waters. Fodder fish populations are probably better able than sport and commercial species to withstand addi-tional mortality on their larval stages. If this pattern holds along the whole California coast, it should be used as basic information in future planning - e.g. the placement of intakes and outfells. This is not a blanket recommendation for placing structures close to ahara, but rather a recommenda-tion to weigh the possible losses of fish larvae in such decisions. OPTIONS AND RECOMMENDATIONS Options San onofre Kalp bed (SOK) and nearshore fish populations are ths major parts of the marine ecosystem that SONGS Units 1, 2 and 3 could significantly ham. Mysids, and perhaps zooplankton, are of less direct interest to society, but they also might sustain significant and quite large impacts.

Io the light of the predictions, MRC reviewed a number of possible recom-mendations that could be made to the Commission:

1. Make no design changes at this time.

Monitor the effects.

2.

Make no design changes at this time.

Examine the feasibility of mitigating some or all of the effects, with a ~ew to recommending mitiga-tion measures to the Commission.

3. Extend the intake pipes to beyond the 30 meter depth.

4. Redesign the diffusers of Units 2 and 3, to convert them to single point discharges, located either 4 to 5 km offshore or very close inshore.

5.

Convert the once-through cooling system to cooling towers.

Option 1 would raquire only a monitoring program, which would be carried out over several years to determine the effects of SONGS on the marine ecoeystlllll.

This progrlllll, in addition, would generate important information for future coastal planning, and would test bow well we can predict the ecological consaquences of a ujor coastal installation.

Option 2 l!IRC has completed a short "paper" feaaibility study of cer-tain kinds of titigatioD (Mitigation Appandix). This study describes various Nthoda of aahancing tiM production of economically important species, such as reef fish cd abalone.

Sout!Mrn california l!dison has

~

-s-established an experimental reef aimed at producing a kelp bed and associated organisms, including fish and abalone.

Other mitigation measures may be feasible.

It should be atrelised that mitigation eould not be expeeted to replace completely the biota lost through SONGS' operation.

San Onofre Kelp bed could perhaps be replaced by a similar kelp bed, but fish losses would probably be replaced (partially) by a somewhat different mix of species.

Lost mysids and planltton are not likely. to be replaced by any known mitiga-tion measure.

k/l adequate mitigation study would therefore need to address the acceptability of "replacing" losses of one species by increasing the production of another.

option 3 The possibility of extending the intakes out to deeper water was suggested previously ~

1979 Interim Report) as a means of (1) reducing the turbidity of intake water, so that the effects on SOK would be reduced, and (2) reducing the kill of nearshore fish larvae. With regard to aim (1),

the turbidity study (Turbidity Appsndix) suggests that much of the turbid water passing over SOK will originate at the inshore segment of tha diffusers and will be carried offshore by secondary utrainment, so that the gain from changing the intakes would be relatively small. li'ith regard to aim (2), our recent analyses show that the larvae of nearshore sport and eo111118rcial species are relatively sparse iu the present intake area, and are quite dense out to about 7 km offshore.

The gain in moving the intakes offshore would therefore be 111Bin1y a reduction in fodder fish kills, while we would likely kill !!2!!. of sport cd c011111111rcial species.

option 4 The diffusers carry turbid water over the kelp bed.

They also wUl cause an unknown, but probably significant, amount of 1110rtality in mysida, plankton and fish larvae.

A single point discharge would greatly reduce this latter 1110rtality, and moving the discharge either close inshore or further offshore would re1110ve the kelp bed from the influence of the dis-charge.

A single point discharge would violate the State thetl!lal tolerances, but Ml!.C balievea this would cause much less ecological damage than the diffusers. *It might be possible to make practical use of the waste heat from an iushore discharge.

Ml!.C has not evaluated in detail the ecological consequences of these two alternatives.

Rec011111l81ldations li'e recommend Options 1 and 2., and recommend against design changes at this time (Options 3, 4 and 5).

Monitoring is needed to measure the effects of Units 1, 2 and 3, as re-quired by the Permit. It is also esssntial that the effects are measured and compared with Ml!.C's quantitative predictions. Part of our study is a unique effort to make such predictions, and it is only by testing them that we can determine if such prediction is possible, how accurate it is, and what changes are needed to make better predictions in future planning.

Pre-dictions of probable effects, whether made explicit or not, are of course an integral part of all coastal planning.

Ve also recommend that MRC's remaining and ongoing prediction efforts be completed.

These are now small studies.

Such quantitative predictions are illlportant, not only in themselves, but as a guide to the future monitor-ing program.

It is important to monitor the success of Southern.California Edison's experimental reef, now established some 5 km south of SONGS.

The evidence

8 on the efficacy of reefa, especially aa a baais for new kelp beds, is equivo-cal and in contention, and this experiment will allow us to judge the best available California reef technology.

MRC will present to the Commission, at a later date, a recommendation on whether or not other mitigation measures should be examined.

We recommend against moving the intake pipes (Option 3), for the reasons given under that Option.

We also recommend against Options 4 and 5 at this time.

Destruction of the offshore portion of the kelp bed is a major pos-sible effect of the diffusers.

However, at this moment we are not certain this will occur, and it is also possible that the effect could be mitigated.

Some mitigation of fish losses may also be possible.

It is possible that we have grossly underestimated the ecological con-sequences of SONGS Units l, 2 and 3. If monitoring proves this to be the case, we will re-examine the possibility of recommending major design changes. PREDICTIONS

!1§!!.

Introduction Most fish caught in Southern California are netted by commercial fishenen, and most come from fishing areas more than a few ldlometers off the coast.

By contrast, most sport fish in Southern California are caught close to the land - within the 33 California Fish and Game "fishing blocks" that are contiguous with the shore.

In this Report we are concerned mainly with those sport fish and with commercial catches taken close to shore, for it is only this nearshore group of fish that SONGS is expected to affect.

In evaluating the predictions, therefore, it should be kept in mind that SONGS is not expected to influence the great bulk of the fish populations that are harvested by California fishermen.

The species that concern us are fish that live as adults mainly within about 4 or 5 km of shore and that produce planktonic (drifting) eggs and larvae in the same zone.

Among these species there are two groups: the nearshore sport and commercial species, the harvest of which is ~de up mainly by halibut, white seabass, kelp bass and sand bass, and the nearshore fodder fish (or forage fish) that form a major portion of the prey of the sport and commercial species.

In the predictions, we present various numbers to help the reader evaluate the likely effects of SONGS.

It is easy to misinterpret these numbers, and we give here some essential background information. If we know the abundance and sizes of all of the halibut, say, in some area along the

7':

en coast, we can calculate the total living weight (biomass) of halibut in that region.

This is called the standing~* Each year, there are additions to this standing stock - some individuals that were larvae grow up to become adults, and many of those already adult grow and gain weight. If we could add up all the accumulated growth (in weight) we would be able to say how much.!!!!!!!. bi011111as bad been added to the population. This is the.!!!!!!!!!!. produc-

~

of new halibut tissue.

We cannot estimate this directly, but a general rule of thumb is that a sport and com=ercial population gains about 60% of its standing stock weight per year. If our harvesting techniques were per-fect we could take all of this production each year as harvest, and keep the standing stock steady from one year to the next. However, inevitably some fish die of disease and parasites, others are eaten by predators, and so on.

The annual harvest, therefore, *is always less than the.!!!!!!.!!!!. production.

In these nearshore sport and commercial species near San Onofre we estimate the harvest is roughly a quarter of production.

As long as the harvest plus other factors do not take more than the annual production, the population will not decline.

However, if, on average, harvest plus other losses are greater than production, the population will decline. If they are leas than production, the population will increase, until it approaches a l:lmit (say its food supply), at which time production vill begin to decline and the population will level off.

We stress that the numbers given below are in all cases appro>dmste.

They give us an indication of the likely size of effects, but they do not tell us precisely what losses will be. Predictions

1.

Nearshore Sport and Commercial Fish It is probable that, because of SONGS' activities, somewhere between 27 and 60 tons of nearshore sport and commercial fish production will be lost annually (Table 1}.

We feel the lower figure is more probable than the upper figure.

Halibut is the species that will be most affected. Fish move about, so any loss of production will be spread over some area.

We do not know how large an area, and provide a comparison between the consequences of spreading the loss over a small (45 km) and a la~ge (300 km) stretch of coastal waters.

A loss of 27 tone would be equivalent to about 6% of the annual produc-tion of nearshore sport and commercial fish in the fou~ fish blocks covering about 45 km of coastline near SONGS.

It is equivalent to about one-third of the most recently documented (1975) harvest of these species from these four fishing blocks (85 tons).

This does.!!2,!;. mean that all of the losses will occur in these four blocks, or that the harvest can be expected to decline by either 6% or one-third.

If the losses were to be spread evenly ove~ 300 km (about three-quarters of the length of the california Bight), then the loss in annual production over this area would be 1%.

The loss in~

could be more than 1% of that caught over 300 km.

For example, to take an extreme case, if all natural losses are unavoidable, than all of the loss would COllie out of the harvest, which, for the 1975 harvest, would decline by roughly 10%.

There is quite strong evidence that the stocks of nearshore spo~t and commercial fish (especially halibut) have declined in the past two decades.

We *believe that these population& are unlikely to be able to compensate for

~ (i.e. make up for) significant additional mortality. However, the projected loss of sport and commercial fish, caused by SONGS, is sufficiently small that ve believe it will not, in itself, have a significant effect on these populations.

Although SONGS alone is expected to have a minor effect upon the popula-tions of nearshore sport and coamercial fish, the cumulative effect of a number of sources of mortality of this order would be expected to contribute to continued decline in these populations. Future planning in the California Bight, therefore, should not evaluate additional installations and other environmental insults as independent evants, but should consider their cu=u-lative effects.

2. Fodder Fish Anchovies probably contribute more than any other species to the diet of nearshore sport end commercial fish. Although enormous numbers of anchovy larvae will be killed by SONGS, we do not expect this vast population to be affected as a result of the operation of SONGS.

Nearshore fodder fish species are also important in the diets of near-shore aport and commercial fish.

The two most abundant nearshore fodder fish are queenfish and white croaker.

SONGS is expected to cause a loss 1n production of nearshore fodder fieh of at least 300 tons per year.* Unlike the sport and co=mercisl species, there is no evidence that the fodder fish populations are declining, so that we could expect some compensation for these losses.

We do not know how much, so we cannot predict a precise net loss. Fodder fish in general move around more than sport and commercial*

species, and the populations in the entire Bight may well be thoroughly

• All weight figures are wet weight snd are in metric tons. mixed, ao that losses would be spread over the Bight (roughly 400 km). lf the losses were spread over the Bight, and if no compensation occurred, they.

would be equivalent to about 7% of the annual production of these fish.

The projected loss of the equivalent of 300 tons of fodder fish produc-tion is owing mainly to the loss of larvae in the intakes.

We expect there will be additional losses caused by the diffusers carrying larvae to inhos-pitable environments offshore.

These losses could be very large - greater than those caused by the intakes - but we cannot predict them accurately.

The projected intake losses alone are sizeable, While we cannot estilllate how the populations will be affected {because we do not know enough about compensation), the accumulation of effects of this order would be expected eventually to cause declines in these stocks. Thus, while SONGS itself may not cause such declines (and we do not know whether it will or not), we would be concerned about accumulating additional losses of this magnitude in the future.

We expect that the direct imping1!111ent of juvenile and adult fodder fish (111Ainly queenfish) in the intakes will cause measurable changes in the age structure and sex ratio of this species to a distance of several kilometers from SONGS.

3. Mechanisms J!'ish !oases are caused by three main mechanisms:

(1) direct impinge-ment of juvenila and adult fish in the intakes, (2) loss of immature stages (especially larvae) in the intakes, and (3) loss of immature stages in the diffusers. Mechanisms {2) and (J) sre the most important.

The diffusers could kill larvae (a) through subjecting them to turbulent shear and {b) by

7' t3 carrying inshore larvae to an inhospitable environment offshore (transloea-tion).

Intake losses: Our recent analyses have yielded a critical piece of info11114tion that 114y be important in the placement of intakes.

We have evidance that the larvae of nearshore sport and c,_rcial fish species are unlike 1110St nearshore larvae and are qnite sparse very close to shore where the intakes are. Because of this peculiar distribution, we estimate the loss of sport and coaaercial fish production, owing to larval 1110rtality via the intakes, to be only 20 tona per year, rather than 160 tons per year aa previously expected, thus reducing tba predicted impact to one that is rala-tivaly minor.

Diffuser losses:

We satimata that relatively few fish larvae will be killed by turbulent shear, and believe that this will be a minor effect.

We also do POt expect tbe larvas of sport and commercial species to suffer trena-location mortality in the plume.

However, translocation may cause very large losses of fodder fish larvae.

4. UevallinB Effects of SONGS SONGS' diffusers will bring extra nutrients to the surface, and move them offshore.

This *could result each year in the production of roushly 460 tons of anchovy.

We believe this will have a negligible effect on sport and eosmercial fish production, and virtually no effect on nearshore sport and commercial fish production. Table 1. Suaury of predicted effects of SONGS Units 1, 2 and 3 upon nearshore fish species. Numbers are matric tona per year.

(1) Losaea by direct impingement of juvanUe and adult fish in intakes Fodder fish Sport and commercial fish

!Uectric rays Other fish (2) Losssa by kill of planktonic stases in intakes Fodder fish Sport and c~rcial fish (3) Damage to kelp bed In sport and c0111111ereial In biomass In production production 31-51 25-41 0-4 7-12 4-7 4-7 7-13 5-8 5-8 3-5 Subtotal 4-11 358 287 3-29 34 20 20 Subtotal 23-49 0-9

()..3 0-3 TOTAL 27-63

~ ~

Introduction

~elp beds constitute a distinct and important habitat in the nearshore

~:-~;ecosystem in Southern California. Over 760 spec~es of animals (inver-

.. ' *.c :es and fish) and over 120 species of plants have been found in kelp ca Southern California. At least two fish species (kelp perch and kelp

..:.. c~; :' *.sh) are rarely found outside of kelp beds, and many invertebrate

>..

_;s occur most commonly in this habitat. In the San Onofre kelp bed (SOK) alo~a we have recorded 164 species of animals and 16 species of plants -

cerc~~nly an underestimate of the actual diversity.

In the three local kelp beds (SOK, San Mateo kelp and Barn kelp) we have recorded 384 species of an~:s end 36 species of plants.

Kelp beds are highly productive of aport fish. including the highly valued kelp bass.

~lp plants grow very rapidly, and as plants die, or parts of plants brea£ off, they produce food for bottom-dwelling animals.

In December 1978, for ~ample, SOK produced an estimated 9 tons of detritus per day.

3an Onofre is in an area where kelp beds ~re (now) rather scarce.

!!a**..-*~=, the local beds maintain ecological continuity between the more

"-"C*H:3ive beds to the north and south.

~storically, San Onofre kelp bed has eXhibited two states:

(a) the "no-c=l" state in which much of the available rocky substrate is covered by kelp as is now the case, but the degree of cover varies; (b) periods following cataatrophic die-offa of adult plants, during which the bed is non-existent, at *'*'Y low coverage, or is recovering. Predictions (l) It is likely that SONGS Units 2 and 3 will alter the normal state by reducing the density of kelp plants in the offshore portion of the bed.

!his is the major area of the bed.

The reduction could be very small or very large.

There are several confounding factors which prevent us from stating a most likely extent of reduction in abundance at present.

(2)

SONGS probably will lengthen the periods during which the bed is absent, or very sparse, following catastrophic die-offs.

(3)

We expect to see some reduction in the abundance of shrimp species in the canopy in a portion of the kelp bed.

No quantitative prediction is possible. This change could alter the diets of fish in the bed.

Mechanisms Turbidity:

SONGS will affect the bed mainly by increasing the turbidity downstream from the points of discharge.

This increase will be small in summer, but in spring it is predicted to lower light levels in the water column.

The reduction at the bottom in the offshore portion of the bed is predicted to be about 4U%.

The lower light intensities that result will probably reduce the frequency of successful recruitment of young kelp plants.

It is also likely to reduce the growth of kelp plants.

Both effects are likely to reduce both the biomass of kelp in the bed and the number of plants.

Fouling:

SONGS' plumes are also likely to increaee the degree of fouling of kelp plants by various invertebrates that settle on to and live on kelp.

Increased turbidity, and perhaps turbulence, are among the mechan-isms that could increase fouling.

Fouling is likely to 1) decrease the rate

71

~ of kelp growth, 2) increase the rete of loss of parts of the plant, and

3) perhepa increase the death rate of plants.

Sea Urchins:

Urchin populations may also be increased because SONGS will increase the supply of particulate organic 1114tter that the urchins can use ss food.

Our studies show that urchins kill a large fraction of kelp plants in parts of the bed, and they probably also interfere with recruitment by grazing on 8111411, young kalp plants.

Sedimentation:

The operation of SONGS is not expected to alter the sedimentation rate in SOK.

Temperature:

Temperaeure changes caused by the SONGS plume will be small and are not likely to affect the bed sigoificantly.

Nutrients: Part of the time, the concentration of nutrients may be somewhat incressed in the water surrounding adult kelp plants, as a result of upwelling via entrai!liiW1t.

This may increase the growth rate of kelp plants.

Competitors:

When kelp is removed from the substrate other plants and animals can grow in its place.

These organisms may prevent or slow the re-colonization of kelp, by taking up the space. Although ve have information on these organisms, it ia not possible to predict whether SONGS will signifi-cantly influence these interactions.

Toxic Substances:

During the course of the studies at SOOGS, circum-stantial evidence has been found for the existence of toxic materials in the.

discharged water from Unit 1.

We can make no definitive statement as to whether or not such toxic: substances will be discharged by Units 2 and 3, except that chlorine will continue to be used on an intermittent basis* ~

Introduction Mysids are small shrimp-like crestures that live in shallow water just above the ocean floor, or amongst kelp canopy and other benthic algae.

At night some of them rise several meters into the water colU11111, and at this time they are more likely to be entrained by SONGS.

Unlike true plankton, they can swim agetnse weak currents, and so can maintain their position to some extene.

Mysids were chosen as a target organin for several reasons.

1)

They hove similar biology to a number of other groups of hypo-plankton" that live close to the bottom.

2)

They are important food items for a number of fodder fish (e.g.

queenfish), which in turn ere fed on by sport and collllllercial fish.

3) Like a number of plankton species, soma mysid species live only close to shore and will be taken into the SONGS cooling system and will also be transported offshore by the diffusers. However, since they have a longer generation time than plankton, they are likely to recover mote slowly from such extra mortality, and are therefore more likely to show local depressions in density.

Mysids are thsrafote expected to be a good "marker" group for the effects of SONGS.

Predictions

1.

Our 131Ysid studies indicate that we should see a reduction in density of about 50% for several kilometers away from SONGS, and 8111aller depressions on the order of 10 lall long.

There are several factors that prevent us from

~ being certain about these effects. Firat, we are forced to make asaumptions about the numbers killed by the diffusers, since we cannot measure this loss.

Second, we do not knOtt how strong compensation will be.

2.

SONGS intakes will kill several billion mysids per year, weighing SQ-60 tons.

The diffusers could kill several hundred tons of myaids. !f, for example, 10% of those entrained by the diffusers were killed by being carried offshore to unfavorable habitat, the annual kill would be rather less than 200 tone.

We are unable, at the moment, to give a most probable esti-mate of diffuser losses.

HYsids constitute about one-half of the total of epibenthic organisms that are subject to entrainment. A similar mortality rate for all of this group would thus give an annual kill of all organisms of this type of about 350 tone.

If these 350 tons were lost to the fodder fish, we could expect an annual loss of fodder fish production on the order of 30 tons. However, the MRC fish study group believes that much of the mysid biomass killed and moved offshore will be eaten by these same fish species in the region of the dif-fusers.

Some mysid material will, of course, fall uneaten to the ocean floor.

There it will join food webs that lead in part to benthic fish.

These food webs are less efficient than the mysid ~ fodder fish chain, so we could expect so~e overall loss of fodder fish production, although much less than 30 tons per year. we*do ~predict, therefore, that the mysid losses will have a significant effect on sport and commercial fish production. ~

Introduction the plankton is made up mainly of s~l drifting organisms that are generally moved about passively by currents. Phytoplankton are single-celled plants that fo= the basis of 110st animal production in the oceans.

Zoo-plankton are small animals, some of which can swim actively and control their movements to some degree.

they include the meroplankton, such as clam larvae, which are the planktonic stages of bottom-dwelling organisms, and holoplankton, which spend their entire life in the plankton.

The predictions focus on the plankton as a balanced indigenous community, and as food for fish.

Predictions

1. the plankton studies hsve established that some zooplankton species are restricted close to shore (within 3-4 km), snd it is probable that SONGS will reduce the local density of this group. It is probable that there will also be changes in the relative abundance of species in the zooplankton assemblage in the inner nearshore zone.

The ~gnitude and extent of these changes cannot be predicted, and will depend on mixing rates, the ability of the populations to eo~pensate, and on interactions between species.

As an indication of the likely scale of the effects, we expect them to be somewhat less extensive than the predicted mysid effects.

2.

SONGS' intakes probably will kill on the order of 10 trillion of the larger zooplankton per year, weighing about 1200 tons.

Most of the zooplankton withdrawn at the intakes will enter the benthic food chain and will be lost as a direct food source for fodder fish.

The fate of these diverted zooplankton is discussed in the Soft Bottom Community predictions.

'7'

!E! We cannot yet estimate precisely the kill of plankton entrained by the diffuser plumes. If 10% of those entrained were to be killed by being moved offshore to unfavorable habitat, the annual kill would be on the order of 4000 tons.

This transported plankton will be eaten largely by the same species of fodder fish that would have eaten it inshore, before SONGS began operation.

We therefore do not expect to see significant changes in the overall abundance of fodder fish or sport and commercial fish as a conse-quence of this shift in biomass.

3. About half of the tima, the diffuser discharges will bring to the surface, offshore, relatively nutrient-rich water from closer to the shore end nearer the bottom.

We estimate that this will result in the annual pro-duction of an extra 84,000 tons of phytoplankton in the mid or outer near-shore waters. The fate of this extra biomass is discussed in the Fish predictions. SOFT BOTTOM COMMUNITIES Introduction The soft benthos com=unity is made up largely of invertebrates (worms, clams, crustacea, etc.) that live in and on the sand, silt and mud bottom.

These bottom types cover roughly 80% of the area in the general San Onofre region.

The distribution and abundance of these species is strongly influenced by the physical characteristics of the sand, silt and mud and by the amount of food material in the area.

The communities close to shore (out to a depth of about 10 meters) are less diverse and less abundant than those further offshore. Most of the species are planktonic in their early stages. Although these communities are not as productive of fish, on a per area pasis, as are reefs and kelp beds, because they are so extensive they help to support large populations of fodder fish and hence of sport and commercial fish species.

Predictions

1.

SONGS Units 1, 2 and 3 will alter the bottom sediments.

Close to the diffusers (within 1 km) the sediments will be coarsened and enriched.

Beyond this area, in a pattern and at distances that ve cannot yet predict, the sediments will become aomevbat finer, and they will be enriched. The general result of these changes will be an increase in the abundance, number of species, and, probably, in annual production of biomass in the enriched region.

2.

SONGS could have a negative influence on the soft benthos community by killing some of the organisms that live on the bottom but that occasionally ria, into the water column.

(This group of organisms bears a broad similarity

1)1 tJi to mysids.} It will also reduce the number of larvae of some species avail-able for settlement, by killing the early stages that float in the plankton.

This could affect the adult density of some species, especially those living in the intertidal and shallow water zones.

Among this group, lobster is a aport and commercial species. However, too little is known about the popula-tion dynamics of the early stages to hazard a prediction about possible' effect on adult densities.

We suspect it will not have a significant effect on the overall production of the community.

3.

The enrichment of the soft benthos is not expected to influence the production of sport and commercial fish. HARD BOTTCM COMMIJNITIES Boulders and reefs near SONGS are covered by a variety of organisms in addition to kelp.

These include smaller species of algae and sedentary animals that permanently attach to the rock surfaces. Apart from their intrinsic value as part of the community, these organisms provide both a source of food for fish and important habitat structure, and they may compete for attachment surfaces with kelp.

There are distinct inshore (intake depth) and offshore (around SOK depth) communities.

Turbidity is higher inshore, and inshore species are more tolerant of this higher turbidity.

They also grow more rapidly than offshore species. It is thus possible that increases in turbidity in the offshore portion of SOK will lead to a change in the community such that inshore species will tend to replace the resident offshore species.

Con-ceivably these inshore species could also slow the recruitment of kelp by outcoapeting it for space.

While these possibilities exist, there is no strong evidence to suggest they will occur.

T

~ RATIO!W.E FISH CONTENTS A.

The affected fish species B. Mechanisms C.

Estimation of probable losses of fish (1) Direct ld.ll of juvenUea and adults in intakes Page 27 28 28 28 (2) l.tilling of planktonic fish egga sad larvae in intakes 29 (3) Diffuser loaaes 33 (4) Losses from damasa*to kelp bed D.

Conversion of losses to biomass E.

Conversion of losses to annual production 34 34 35 F. Conversion of fodder fish losses to sport and commercial losses 35 G.

Compensation ud declines in nearshore fish species

8. On-shore off-shore water DIOV8IIIellts I. Upwelling eauaed by SONGS 36 38 38

1(1 t:::J In this section on fish we do not give a separate rationale for each prediction, since the same types of analyses underlie predictions 1 and 2.

A.

The affected fish species SONGS Units 1, 2 and 3 are most likely to have a significant effect upon fish species that live as adults mainly nearshore (within about 4 km of shore), and that produce planktonic (drifting) eggs and larvae in the same zone.

Most species of fish in the SONGS area are of this type.

However, most individuals, and most of the total tonnage of fish are Northern anchovies.

Anchovies also extend well offshore. There are several hundred billion anchovies in the California Bight, they move enormous distances, and SONGS will not significantly affect the population of this abundant species, although the Plant will kill large numbers of anchovies.

They are not considered in most of the analyses below (but see Section I), which concern nearshore species only.

A numerically small group of nearshore species either carry their young internally, or have planktonic larvae but lay attached, not free-floating, eggs.

This group is also excluded from subsequent analyses.

We will be concerned mainly with those nearshore fish species that produce both planktonic eggs and planktonic larvae.

These species fall into one of two groups.

(1) Forage or fodder fish.

These species eat plankton, small bottom-dwelling organisms, mysid shrimps, etc., and are themselves food for sport and commercial species.

The major species in this category are queenfish (Seriphus) and white croaker (Genyonemus).

(2)

Sport and commercial fish are the second group.

Among nearshore species, halibut and white seabass are the main commercial species while kelp bass and sand bass, and halibut, are the main sport species.

These four species made up over three-quarters of the 1975 sport and commercial catch of nearshore fish in the fish blocks near SONGS.

B.

Mechanisms There are six known or suspected mechanisms through which SONGS can affect fish populations.

These are:

(1) Killing juvenile and adult fish as they are taken into the intakes of the cooling system (via impingement and entrapment).

(2) Killing planktonic eggs and larvae that are taken into the intakes.

(3) Killing planktonic eggs and larvae that are caught up (entrained) by water jetting out of the discharge or diffuser systems.

(4)

Loss of fish from special habitats (e.g. kelp).

(5)

Loss of fish food that is moved by the cooling system.

(6)

(Sub)lethal effects of discharged organochlorines.

We have no evidence that mechanisms (5) and (6) will operate to affect sport and commercial fish production, and they will not be discussed further in this Report.

C.

Estimation of probable losses of fish (l) Direct kill of juveniles and adults in intakes Unit 1 kills, on average, 16.7 tons of fish per year.

The fish are disposed of on land.

Of these fish, 10.2 tons are fodder fish, 2.5 tons are electric rays (which are of scientific and economic importance), 2.4 tons are nearshore sport and commercial fish species 1 and 1.6 tons are other species.

The intake structures of Units 2 and 3 have been modified to reduce the fraction of fish taken in by the intakes.

In additionf a fish-return

m

~ system bas been devised to return those caught back to the ocean.

This system bas not been tested. Tbe MRC fish study group feels that the fish-return system is likely to kill or fatally injure most fish that pass through it.

If the new systems are SO% efficient, the total intake mortality will triple.

If they are completely inefficient, total intake mortality will increase about 5-fold since all three structures provide about five times as much attractive "reef structure" as Unit 1.

(The volume of -water taken in by all three units will be six times that taken in by Unit 1.) If the fish-return system is not more than 50% efficient, the annual impingement fish kill will fall between 3 and 5 times that of Unit 1, or 50-84 tons, of vhich 7-12 tons will be near-shore sport snd commercisl fillh.

This is equivalent to 4-7 tons of nearshore sport end commercial fish production.

The losses to Unit 1 already produce measurable effects on queenfish.

Tbe population of this species within 1:! km of the intake (and perhaps as far as 2 km) has fewer young fish and fewer females than more distant populations.

Young and female fish are precisely tha groups taken in selectively by the intakes. Two-thirds (by weight) of the fodder fish taken in are queenfish.

Some 31-Sl tons of fodder fish will be impinged.

These fish vould otherwise have contributed 25-41 tons of fodder fish production (Table 1).

(2) Killing of planktonic fish esss and larvae in intakes MOat nearshore species spend 2-4 months as planktonic eggs and larvae and throughout this stage can be caught up by the intakes or diffuser -water.

This 1a the major source of mortality. It is estimated by a somevhat c0111plex procedure involving a model of fish mortality, and ws deact'ibe the methods only briefly. Tbsre are a nuaber of steps in this procedure. (a)

Tbe density of eggs and larvae of various ages, in vater at various depths and distances offshore, is estixnated from samples.

(There is a tendency for older larvae to occur inshore and nearer the bottom, at diffuser and intake depths.)

Next, the rata at vhicb SONGS will withdrav vater from each of these locations is estixnated (from a modal of SONGS hydrodynamic behavior).

This gives the.!!!!!!!2!!I. of aggs and larvae that will be entrained. Finally, an assump-tion is made about: the fraction of entrained eggs and larvae that will be killed. All of those passing through the intake are assumed to die.

(Similar calculations can be made for those caught up by the diffusers, but ve cannot yet estixnate the fraction of those taken up that will be killed.)

These various estixnates allov calculation of the expected number of eggs and larvae that will be killed per unit time (say, each day), immediately after the Plant is turned on (Fish Appendix 1).

We cannot assume this kill rate vill continue indefinitely. For example, some vater that bas been affected by the Plant may remain in or return to the vicinity and mtx with "new" vater that moves into the area. llhen this happens, the local density of eggs and larvu will be lover than elsewhere, and fewer eggs and larvae will be killed per unit time.

A detailed model of the current rqime in the SONGS area could be used to estimate the rate of replenishment of vater in the area, and hence the local density of eggs and larvae exposed to SONGS.

Such a model vas not available vhen the present calculations vere made.

(b) Instead, a model wu nsed that simply assumed that SONGS will dra'!'

eggs and larvae only from some specified region along the coast.

Inside this region, all eggs and larvae are aasllllled to be equally vulnerable (good mixing

'j'1

~ is assumed).

No egg or larva outside the region can be killed by SONGS and no eggs or larvae can leave the region. the model has the following features (Fish Appendix 1):

Eggs are produced in this region at s constant annual rate that is the same as elsewhere.

(this is essentially the conservative assumption that, even if SONGS kills many plankters and subsequently lowers adult density in the region, reproductive fish will move in from elsewhere.)

The model calculates the chance that an egg or larva of a given age, within the region, is killed by SONGS before it reaches the next age class (which is 2.5 days older). this is done for all age classes up to the point when the larva becomes a juvenile (4 months in queenfish, for example).

Since eggs and larvae die off extremely rapidly due to natural causes, most of them are not killed by SONGS but die of natural causes. This natural death rate is taken into account by the model.

'!he chance of any individual being killed by SONGS before it moves out of its age class depends on the size of the region chosen (the chance is smaller when the region is bigger because within 2.5 days a smaller fraction of the water in the region passes through'SONGS).

Clearly, if a very small region is chosen, a given individual can be exposed to risk on different occasions since the same parcel of vater passes through SONGS many times.

In this case, the density is rapidly depleted, the fraction killed is high, and moat larvae do not grow very old.

On the other hand, the nwnber killed is somewhat smaller.

Since the natural mortality rate is high, there are slvays far fewer older larvae than younger larvae and eggs. This is reflected in the predicted SONGS kill. For example, under one set of assumptions, SONGS will kill in a year 16 billion eggs and 4 billion larvae of nearshore fish.

Clearly the choice of the siJ:e of the "affected region" is somewhat arbi-trary. Choosing a very small region (say l b) is squivalent to assuming virtually no currents along the shore. and hardly any replenishment of the waters armmd SONGS by "new vater. this will overestimate the degree of local SUPpression, but will underestimate the nuabsr killed - larvae from else-where that in reality would get to SONGS are not counted.

On the other hand, choosing a very large rsgion (say several hundred kilometers long) is equiva-lent to assuming that fish eggs and larvae move huge distances in their lifetimas. This would maximize the number killed, but (especially since thorough mixing is asswned) it would spread the effect out very thinly.

We feel that this latter scenario is closer to the real situation. 50 km wss chosen as a compromise between smaller regions within which complete mixing can bs asswned, and larger regioua within which all doomed fish larvae are certain to have been produced.

SONGS!!!!! kill billions of eggs and larvae, and the degree of movement of eggs and larvae will determine whether there is a pronounced local depression or a less obvious, but much more extensive, depression. If there is no re-entrainment of "old" water by SONGS, a choice of 50 km will underestimate the number of eggs and larvae killed.

The result of the model's calculations is a predicted number of eggs and larvae killed per year (breeding season) in each age class.

(c) These predicted losses of eggs and larvae are then converted into an equivalent number of 13 month old fish (Fish Appendix 1).

(An age of 13

'T'

~ 1110nths is chosen primarily because this corresponds in size to that of the aver&Se fodder fish eaten by aport and commercial fish.) the idea involved in calculating 13 1110nth old equivalents 1a aa follOVII:

an egg baa roughly 1 chance in a million, under natural eonditiOilB, of becoming a 13 month old adult. Therefore, if SONGS kills an en, this is equivalent to killing only one-tlillionth of a 13 IIIOll.th old fish, because in all likelihood the en wuld have died anyway.

Bowaver, if SONGS kills a 4 _month old larva it baa killed the equivalent of.4 of a 13 111011th old adult, because a 4 111011th old larva under natural conditiona baa a 40% cbence of becoming a 13 month old adult.

It is predicted that SONGS will kill the equivalent of several million 13 month old adults of nearshore fish species.

At the moment, age distributiona of larvae are available for only the two major fodder fish species.

To estimate losses of sport and commercisl species ve have therefore assumed that, averaged over the season, the aport and commercial species have the same age distribution aa these two fodder fish species.

The estimates of aport and collll8rcial losses owing to larval 1110r-tality therefore are based on this, ss yet untested, assumption.

(3) Diffuser losses (a)

Turbulent shear losses There is evidence from the literature that fish larvae die when thsy are subjected to shear forces on the order of several hundred dynes/em2 over a period of several minutes.

Losses due to this mechanism ware estimated in two steps (Fish Appendix 1). Firat, the fraction of secondarily entrained water that is likely to be subjected to shear forces on the order of 100/cm2, or greater, vas calculated.

Second, the number of larvae subjected to this stress was estimated from known larval densities and from the estimated amount of water entrained. These calculationa suggest that only a relatively small 11UIIIber of larvae v1ll be killed in this way.

(b) Translocation losses Nearshore fodder fish larvae show a very clear pattern, in which density falls off very rapidly several kilometers from shore.

The pattern suggests that larvae that are carried farther offshore die.

During some parts of the year, SONGS' diffuser plUIIes are ezpected to move some inshore water to an area S Ita or more offshore.

The larvae of sport end cCHEereial fish species extend from close to shore to about 7 km offshore.

We therefors do not expect SONGS to cause translocation mortality in this group.

At aome ti111118 of' the year, especially when they are older and more valuable", the larvae of both queenfish and white croakers do not extend beyond 2 km from the shore.

We therefore expect large translocation losses of fodder fish larvae, but we are not able to maka a quantitative prediction.

Some idea of the possible magnitude of these losses can be gained by noting that if 10% of larvae entrained by the diffuser plumes ware to be killed, total fodder fish losses would roughly double.

(4) Losses from d!ll!!8e to kelp bed Damage to the kelp bed and its biota may be anything from negligible to extreme <-ee ltelp Predictions).

and 1).

Conversion of losses to biomass {weight of standing stock of fish) the losses of 13 month old "adult-equivalents" were divided between sport commercial fish and fodder fish according to the frequencies of these two

1(1

~ types in the larvae affected.

Among nearshore planktonic spawning species, in general, four-fifths of the larvae are fodder fish and the remaining one-fifth are sport and commercial fish. However, their relative frequencies vary with proximity to the shore and with position in the water column, and these differences were taken into account.

Next, numbers lost were converted to a weight (biomass) for each group (aport and commercial fish liva longer than fodder fish and are larger, so the conversions are different) (Fish Appendix 1). The idea here is that, once SOHGS baa been operating for several years, 1, 2, 3,

• year old fish are all affected and each year there will be an average loss of fish weight, spread over all ages, in each species.

E.

Conversion of losses to annual production l!ach year, each fish population produces a certain tonnage of "new" biomass, through reproduction and growth.

In a perfectly balanced fishery, esch year this same amount of tonnage would be consumed ~ by natural deaths plus the fish harvest. The annual production of a typical sport and commer-cial population is reckoned to be about 60% of the standing stock (biomass).

Thus, when the equivalent of 100 tons of sport and commercisl biomass is lost as larvae and eggs, this is equivalent to a loss in production of 60 tons.

Similar calculations are possible for fodder fish, where the figure is thought to be 80%.

F.

Conversion of fodder fish losses to sport and commercial losses Sport and commercial fish depend predominantly on fodder fish and, since the biomass of the latter is expected to be reduced, there should be less food for sport and commercial fish. It is difficult to know how to estimate the effects on sport and commercial species of this predicted loss of fodder fish production. A stendard rule of thumb is to assume that 10 pounds of fodder fish production yields one pound of sport end commercial production - a 10%

"transfer efficiency". Howevar, if sport end colDIIU!rcial fish population are being held at relatively low densities, say by fiahing.(Section G), then changes in food supply may have little or no effect on their production.

In addition, the fodder fish losses may be partly or largely compensated for (see next section). These considerations suggest that 10% is too high a figure.

We think it unlikely that aport and commercial fish production is totally unrelated to fodder fish production, and so assume a 1% relationship as a lower (and more likely) bound.

G.

Compensation and declines in nearshore fish species It is possible thet reductions in larval fish density caused by SONGS would lead to higher survival of the remaining fish larvae (for example, by making more food available to each larva). There is, at the moment, no good evidence for such compensation in marine larval fish, and there are ~ priori reasons for suspecting such compensation would at best be weak.

First, fish larvae are already very sparse.

Second, it iB likely that "chance" (density iodependent) factors dominate the mortality of these small organisms.

Third, much of their food will be killed along with the larvae themselves.

Another possibility is that juvenile or adult fish might survive, grow, or reproduce better in response to lowered density of juveniles.

'We think this is_ possible for fodder fish because there is no evidence that their numbers have been declining. However, we think it unlikely that compensation in nearshore sport and co=mercial fish would be adequate in the face of-significant

rr IS a:tra mortality.

The main reaaon for this view is that these species appear to have decline<! in Southern California since the mid-60s (Fish Appendix 1).

The evidence for declines in nearshore aport and commercial fish species ill by no IIIUII8 tmequivocal.

We have to rely on indirect measures of fish atoci<a.

The major evidence ia from California Department of Fish and Game recorda of apoet and cOBiercial catches.

These. sugsest strongly that halibut, in particular, baa decline<!, that kelp haas and sand bess may have decline<!,

and that the more desirable nearshore sport and couaercial species u a group have decline<!.

Several araumenta can be made ap.inat these conclusions.

Counter-evidance, tosether with COIIIIIIIIlta, is as follova:

(1? Populations fluctuate naturally, and these species a~d strong declines in the 1950s, followed by a recovery.

Populations do fluctuate.

But this ia not evidence that current declines are "natural" and can be isnore<l.

The declines in the 1950s, for u:aple, lllllY have bean cause<! by loss of kelp be4 habitat, and DDT in the Bight, and these tole 11111chania11Ul are nov diminiahe<l.

(2)

Catches of fish in ~r planta do not show clear evidence of declines.

Bovaver, the data from illlp~t by ~

plants suffer several de-fects. Fint, such data are hiably influenced by cetcbability of fish (which ia influence<! by annual variations in the weather), as well as by their density.

They usually are available for only a few years in the 1970s, and such varia-tiona in catchability could easily ooacure reel trends.

Second, the data are e:.rtrllllllely variable. and this could obscure trends oftr this abort period. Third, the data.!!.!. for only the 1970a, often not for the whole decade, and the Fish and Game data ahov that the decline vas most precipitous in the mid to late 60s and h88 baen rather alight in the 1970..

(The Fish and Game data are !!!!!S!!. lese variable than the Power Plant data, especially in the 1970s.) Thus, va vould not evan necessarily expect to see a decline in these Power Plant data.

On halance, va believe the data aupport the conclusion of a decline in desirable nearshore sport and commercial fish.

H.

On-shore off-shore water movementa The predictions bave not taken into account the possibility of larse scale onshore and offshore IIIOVements of vater.

(MRC is now measuring this pheno~~~~non.) Such 110V8mellts could create "circulation calla" that 110uld slow dovn the longshore mov8111111t of esse and larvae {although it is possible that, by choosing vater layers, larvae could escape from such calls). This vould re<luce the satilllated loss of larvae, but vould create a more detectable local depression in larval density around SONGS.

I. UpvellinJ! cause<! by SONGS Some of the vater entrained by SONGS' diffusers will come from below 7 111 depth. Water at tbia depth in the resion of the diffusers ill rich in

• nutrients, but bas low light levels, so that it produces little phytoplankton.

The diffuser plume vill senarally move this (and other inshore water) closer to the surface, where there is more light, and farther offshore. This will result in an absolute increase in phytoplankton production in this region.

We estilliate (Fish Appandix 2) that, eech year, some 84,000 tons of additional phytoplankton will he produced. Most of tbia will he eaten by

rr'

~ zooplankton.

Although it is not possible to say exactly how this production will pass up the food chsin, a reasonable estimate is that half of the phyto-plankton will be eaten by microzooplankton, then by macrozooplankton, end then fodder fish.

The other half of the phytoplankton will be eaten by macrozoo-plankton, and then by fodder fish. In this region (roughly ~ km offshore) the major fodder fish is the anchovy, and most of the new production should pass to this species. A transfer efficiency of lO% would produce, in tons of fodder fish:

[4.2 X 104 X 10-2] + (4.2 X 104 X !0-3) = 460 tons.

During these transitions the new production (as phytoplankton and zoo-plankton) will be moved away from the area of production and thoroughly mixed.

The anchovy population is also extremely mobile and well mixed, so this produc-tion of anchovies would he expected to be spread over a very large fraction of the Bight population.

460 tons is a miniscule fraction of yearly California anchovy production, which is about 1-2 million tons.

We believe it would not result in any real increase in yield to sport and commercial fish. It should be remembered that we have made a similar argument for ignoring anchovy losses: each yflllr, SONGS will kill on the order of lO timaa as many anchovy larvae as other fodder fish larvae, and the fodder fish losses themselves are equivalent to more than 300 tons of production, but" predict no effect from these losses. Clearly, in "production equivalents", tbe anchovy losses are much greater thsn 300 tons, but we believe it is sana1ble to assume that perturbations of this order, spread over the whole anchovy population, will have no effect on adult anchovy standing stock. and hence prodnct:lon. As discussed in Section F, the transfer efficiency from fodder fish to sport and commercial fish probably lies somewhere between 1% and 10%, and we have argued it is likely to be close to 1%. If the increase in anchovy production ~

to be passed on, we would expect it to produce an extra 5-46 tons of sport and commercial fish, and believe the lower figure much more likely. Most o£ this production would !!!!.!:, be in nearshore sport and commercial fiah, since the masa of the anchovy population is offshore.

KELP CONTENTS I. Biology of Kelp (A)

Normal" conditions (1) Reproduction, and recruitment of juvenile plants (2) Survival froa juvenile to adult stage (3)

Sumi:llary of "noraal" kelp population dynaaics (B) Catastrophes II. Estiaating the Effects of SONGS Units 2 and 3 (A) Predicted effects on kelp reproduction (B)

Predicted effects on kelp growth and survival (C)

Other factors associated with SONGS rb

~

(1) Sediaentation (2) Sea urchins (3)

Toxins (4)

Teaperature (5) Nutrients (D)

Overall. effects on the kelp bed (E) Effects on shrimp in the kelp canopy Page 42 42 43 46 47 47 49 49 52 55 55 55 55 56 56 56 56 I. Biology of Kelp We begin by looking at the basic population dynaaics of the San Onofre kelp bed.

(A)

Normal" conditions It appears that, even in the absence of catastrophic events, the kelp bed is rarely in a "steady-state" or equilibrium condition. It is instead dominated by physical and oceanographic conditions that are highly variable.

In the present study (1976 to 1980), only by the end of 1979 did SOK cover most of the cobble substrate available. Naturally,the amount of kelp (number of plants and areal extent) on any section of the bed fluctuates in response to changes in bottom conditions, storms that tear adult plants from their sites of attachment, water temperature, availability of light and nutrients, grazing by sea urchins and probably fish, fouling, and periodic recruitaent.

Patches of kelp within the bed increase and decrease and even disappear and reappear under normal conditions.

Recruitaent of new plants is a major dynamic event that is episodic, in response to seasonal and annual variation in physical and chemical condi-tions. lt appears that recruitment occurs, on average, only once every three years.

(Hovever, recruitment rate has been examined, in this and other studies, for a total of only 12 years or so.) Although kelp has a complex life cycle (Figure l),.for present purposes there are only two important pro-cesses affecting recruitaent of adults:

(i) the ability of the tiny male and female stages (gametophytes) to reproduce and hence produce the microscopic first stage of the actual kelp plant (sporophyte); (ii) the ability of juvenile plants to grow up into adult kelp plants. Experiments have shown that light

rp

~ is an essential factor (but not the only factor) controlling theae two processes.

We need to look briefly at the dynamics of the life cycle.

(1) Reproduction, and recruitment of juvenile plsnts The adult plants produce minute propagulea (zoospores) that settle on the bottom and become either tiny aale or female stages called gametophytea.

Each adult plant producss extremely larae numbers of these propagulea, perhaps continually throughout the year. rhus it ia probable that there are gamato-phytes present, moat of the time, in abundance, on suitable areas of the bottom close to adult plants. the critical factor is the occurrence of a combination of suitable physical conditions (including, at least, adequate light and nutrients) that allow gametophytes to reproduce.

The gametophytes that do reproduce, produce microscopically small kelp plants. This type of life cycle is known as alternation of generations. In kelp the microscopic gametophytes are the sexual stage.

The sporophyte (the actual kelp plant) is the asexual stage. It is also microscopically small to begin with, but passes through juvenile and subadult stages to become the massive adult kelp plAilt.

Gametophytes are killed by a variety of factors - abrasion, burial by sediments, and grazing by anilllels - and only a small fraction of them survive to produce sporophyte& (Kelp Appendix 1, p. 150). Even so, after a success-ful reproductive "set", there are thousands of tiny sporophytes per square meter of cobble substrata. Unfortunately, it is extramely difficult to study these microscopically small plants in natural conditions. Quantitative studies have been done only on larger plants that have reached a height of more than 10 Cl!l (.4 inches),

At about 40 Cl!l (.16 inches) the plant becomes a juvenile (Figure 1). Once again, a variety of factors ld.ll most of the sporo-phyte& before they become juvenile plants.

It appears that the physical environment affects theae processes in the follovins way.

Reproduction by gametophytes requires adequate light and, probably, a hiSh concentration of nutriants in the bottom water. When these conditione prevail, the gametophytes abaorb sunlight and nutrients each day, until they uture to a reproductive condition. Field experiments show that very fev sporophytes ever Appear froa gametopb1tea planted out 1110re than 40 days. rhus, in the field, 40 days apparently is tbe max::IJmDu period during which this stage can accumulate the aunlisht needed for survival and reproduc-tion.

OVer this.period they need an average of at least.43 Einstein& per m2 per day (Kelp Appendix 2, p. 5).

(Onder good field conditions it is likely that the average successful gamatophyte manages to accumulate enough light in about 20 days.)

The critical question for sporophyte recruitment, in any given year, is therefore: during the period in which gametophytea are present, what is the probability (.a) that enough light can be accumulated during at least one 4Q-day period (called a "light window"), and (b) that nutriEmts sre also adequate during the light window?

It Appears that these two conditions co-occur only rarely.

(a) The frequency of light windova varies with the situation. ln a very sparse part of the kelp bed, where adults were absent and vegetation had been cleared, all of the spring season conAisted of light windows (Kelp Appendix 3, Table 1,

p. 5). However, in darker portions of the bed, where adults are present in abundance, none of the 40-day periods appeared to have received adequate light

rr

~ on the bottom. With a light understory of other algae, and heavy adult canopy, about 30% of 40-day periods were light windows on the bottom.

(b) It appears likely that nutrients are adequate only during periods of upwelling. In any given spring these periods last for only a few days, and occur not more than a few times per season (Kelp Appendix 1, Figure El,

p. 260).

Suitable conditions for reproduction occur mainly in the spring, although occasionally also in the fall. It appears that adequate conditions for reproduction occur, on average, only once every three years {Kelp Appen-dix 2).

At. any one time the bed is thus generally dominated by s "cohort:"

of adult plants from a single episode of reproduction.

As discussed below, SONGS is predicted to decrease the frequency at which conditions become suitable for reproduction.

We cannot predict whether or not SONGS vill affect the.!!l:!!!!!l!!. of sporophytes or juvenile plants that arise from any given successful reproductive set. It is likely, however, that some factors will not have much effect on the number produced:

Thus, unless the density of adult plants is catastrophically reduced, we assume (a) Each adult plant produces enormous numbers of gsmetophytes.

that there will be enough gametophytes present to replenish the bed even When adult density is low.

(This is equivalent to assuming there is density "compensation" in the survival of these Sllllll stages.) There must be some very low density of adult plants at which replanisbllent through a single reproductive set is not possible, but ve lllllka the conservative assumption that it is very low, lovar than is encountered during normal" conditions. (b) With respect to light levels, reproduction is all-or-nothing.

When adequate light is available, the number of tiny new plants (sporophytes) produced is independent of the light level. The number produced appears, instead, to be associated vith the amount of nitrogen in the bottom waters, and this is not expected to be affected by SONGS.

The survival of sporophytes to the juvenile stage is determined by a range of factors (abrasion, sedimentation, gra:ing).

(2) Survival from juvenile to adult stage Juveniles frequently suffer a higher death rate than adults (Kelp Appendix 1, pp. 93 and 95), so anything that prolongs the juvenile stage vill reduce both the eventual number of adults and the average density of kelp plants. Light affects the growth rate, and so does fouling.

These factors are discussed later.

The growth rate of juvenile kelp plants is highly variable.

Some plants in a group develop from juvenile to adult in less than three months, while others take more than 13 :months.

The survivorship from juvenile to adult stage is also highly variable, and depends on, among other factors, both the initial number of juveniles and the number of adults present. The fraction surviving tends to be higher when (a) fever juveniles are present initially (ltalp.Append:l.:lt 1, p. 82), and (&) fewer adults are present (Kelp Appendix 1,

p. 84, and ltelp Appendix 2, p. 10). These relationships reflect an important result: except when very low densities of juveniles are present, the final number of adults present 18 roughly constant.

(This means there is strong "compensation" or "densiry-dependence".

U some factor reduces juvenile density, the nllllber of adults produced may be relatively unaffected.)

'T

!::::1 (3)

SUIIIIllary of "normal" kelp population dynamics A final piece of information completes the picture of "normal" kelp bed population drnamics, namely that the average adult plant survives for about 12 months (Kelp Appendix 2, p. 11). That is, if we start out at some point in time with a cohort of adults produced by a successful reproductive "set" a year or more earlier, we can expect roughly half to die within 12 months.

By the end of two years roughly 25% of these adults will remain alive, and by the end of three years, roughly 12~% will remain alive. At this time,

.!1.!!. average, we could expect another cohort of adults to appear.

In reality, of course, the dynamics would not follow this average pattern, but would vary around it. For example, deaths occur mainly in winter storms, which vary in their severity from year to year; again, reproductive sets will sometimes be spaced one or two years apart, and sometimes four or five years apart.

The ~of kelp plants in the bed thus fluctuates, rising rapidly after a successful recruitment event, and declining thereafter. However, the canopy area of the bed will not clearly follow this pattern since the surviving plants will continue to grow.

The canopy area csn thus increase even though the number of plants may be decreasing.

(B)

Catastrophes We know little about the frequency of catastrophes in the SONGS area before the 1950s. Certainly the kelp beds in the general area were more exten-sive and continuous when they were observed at various times earlier in the century than they have been since (Kelp Appendix 1, p. 12). It is likely that much of the cobble in this area has been covered by sediments since then.

We do not know, however, if the beds were severely reduced between the infrequent observations made before 1950.

Two catastrophic die-offs have occurred since 1956 {Kelp Appendix 1,

p. 12).

The first, in 1958-59, was associated with high summer temperatures (hut may have been caused by associated low levels of nutrients). At this time 90% of Southern California kelp beds were destroyed.

SOK was not re-established for a period of 12 years (by 1972). In 1976, again a year of unusually high temperatures, SOK suffered a partial die-off, being reduced to less than 10% of its former extent, and only in the offshore segment did plants remain.

Recruitment occurred about a year later, and recovery of the canopy took almost two more years.

There are two means by which kelp disperses and, hence, beds recover or become re-established. First, the adult plant casts its mictoscopic off-spring varying distances.

Many offspring probably fall very close (a few meters) to the plant.

(Observations at SOK show that some offspring may be dispersed one or two hundred meters from the bed, but we do not know if these were offspring from plants attached in the bed, or from plants that became detached and drifted from the bed.)

Secondly, adult plants, torn loose in storms, drift and sometimes cast spores on suitable substrate far from their point of origin. Re-establishment of a bed therefore depends on chance events, and seems more likely when a source of "colonists" is close by.

This is one reason why the longshore continuity of beds is important.

Recovery of a kelp bed that has been drastically reduced, but not exterminated, depends mainly on local reproduction.

Observations at SOK, in the very successful reproduc-tive season of 1978, suggest that a la:rge "set" of new plants can arise from quite a sparse kelp bed, and that recovery can be rapid if the catastrophic

~* die-off is followed quickly by successful recruitment.

By cont'l'ast, the 1958 catastrophe suggests that IIUljor catastrophes can be"folloved by very long recove'l'Y periods because no o'l' ezt'l'~Y few plants survive locally.

II. Eat:li!Ult:lng the Effects of SOHGS Unite 2 and 3 (A}

Predicted effects on kelp reproduction The two major factors affecting reproduction are light and nutrients.

Increased turbidity caused by SOHGS' discharge will reduce the light in SOK during spring, the ma:ln reproductive season.

The probable effects on repro-duction vera estt=&ted by first calculating the expected reduction in light end, second, by calculating bow this should effect reproduction.

SOHGS is not expected to alter nuerients on the bot tOll, wltere reproduction occurs.

The probable levels of light that will preva:ll in the kelp bed ones Units 2 and 3 are oparating were calculated in four steps (Kelp AppendiX 1, pp. 222-241, and Turbidity Append!%).

Firat, 8111bient light lavale near the bottom vera recorded.

Second, a computer s:lmulatiott model of water movements near SONGS, including those caused by SOHGS' intake end diffuser systems, vas developed.

Thie vu basad on information obtained from current meters placed in the ocean near SOIIGS, and from a physical model of SOIIGS-induced water mov-nta produced for Southam Califomis Edison.

Third, measurements of natural turbidity levels were lllade in spring end sllllm8r.

This inforJIII!.tion allowed prediction of expected levels of turbidity in the kelp bed for these two seasons. F:lnally, 118&8UH11811ts of light and turbidity levels in the field yielded a at'l'ODS quantitative relationship between light and turbidity. The calculations predict (conservatively) that in eprins, in the 6-ost important) offshore half of the bed, subsurface light levels on avarase will be reduced

-so-by fr0111 2S% to SS%, with a 'l'Oughl.y 40% J:eduction be:lng 11!08t likely. No 8illt1i-ticant reduction in light is expected :In the elnady turbid :Inshore segment.

The offsbo'l'e half of the bed bas been the moat persistent du'l'ing cstast'l'ophe, has the densest canopy cc.mar, and constitutes 70% of the total SOK canopy cover.

Subsudace light will ba much leas affected :In late *-r.

A 40% reduction :lt1 subsurface light will reduce the number of 40-day light wiudove, and hence the probabUity of recruitment.

The emount of reduc-tion depends on the prevail:lng light regime. In a clasr part of the bed, were ell 4G-day periods are suitable, a 40% reduction in light would cut the number of light windows by 2o-30%.

At other parts of the bed, IIbera light windows are already scarce, the reduction could be close to 100%.

We will use a 20% J:eduction as a conservative estimate, aince the moat critical recru1t-1Ullt events occur vben the bed is sparse and therefore ambient light levels will be high.

To eat:llllate the potential effect of this reduction in underwate-r illUIIl:lnetion on reproduction, a modal of reproduction is useful.

A crude modal, assuming that only !!!!!. coincidence of adequate light and nutrients is needed to provide succauful recruitment in a season, is as follows.

In a season of D days, there is, each day, probability v that the day is the first of a light window, p'l'Obab:llity n that nutrients are adequate, and probability 3 that there is an adequate supply of gametophytas. The probab:llity that a stven day will initiate successful recruitment is then vgn. If 4o-day periods can be treated independently, then the probab:llity that at least one day in the season will initiate recruitment ia 1-(l-wgn)D (Eelp AppendiX 4).

rr

~ This model can be used to estimate how a reduction in the number of light windows will affect recruitment.

Suppose we reduce the number of light windows to a fraction (p) of their original number (in the case of a 20%

reduction, p *.8). The probability a given day will begin a light window then becomes pw, and our model ia 1-(1-pwgn)0*

We assume that only when SOK is destroyed is g < I, so except when the bed is absent, the model becomes 1-(1-pwn) D.

If wgn, or wn, is small, (1-pwgn)0 ~ 1-Dpwgn, and the reduction in the probability of successful recruitment will be by a factor close to p. Other-wise the reduction will be less than p. There are three cases: normal SOK population dynamics, SOK absent (when it is destroyed), and SOK reduced (when it is at very low densities).

In normal times there is very little light in the bed and w is small.

Furthermore, those partially shaded areas that do provide some windows suffer a greater than 20% reduction in windows.

Thus a 20% reduction seems to be a conservative estimate. Note, with p *.8, the average time between recruitment events increases by s factor of 1/p

• 1.25.

That is, the average time between recruitment events would be expected to increase from about three years to almost four years.

In the absent phase, g is very small, since recruitment depends on the rare event of a drifting kelp plant dropping spores on suitable substrate.

Thus a 25% increase in the time to recruitment is a reasonable estimate.

Even in the reduced phase, when w is intermediate and g = 1, n is likely to be very small and the time between recruitment events should increase by 25%.

-S2-Overall, therefore, it is reasonable to predict a 20% reduction in the probability of successful recruitment, and therefore a 25% increase in the average time between recruitment events.

(B)

Predicted effects on kelp growth and survival Light and fouling of kelp plants are the major factors that are expected Here to affect kelp growth.

We discussed expected changes in light, above.

we first describe fou11og and then discuss the relationships among light, fouling, and growth and survival of kelp.

Fouling:

Several species of small invertebrates settle and attach to kelp plants.

Some build tubes from particles in the water, others merely live on.the kelp blades.

Under normal conditions in SOK, fouling of juvenile kelp plants is rather light, although the fouling organisms are present.

Several experimental studies show that the abundance of these fouling organisms on kelp plants and other surfaces is greater the closer they are to the discharge plume of Unit 1. This increase is caused by (probably several) factors associated with the plume, including increased particles in the water, and increased turbulence which stimulates the planktonic stages of some organisms to settle. lt is also associated with lower light levels, but is probably not caused directly by reduced light.

There is evidence (Kelp Appendices 2 and 5) that increased fouling can reduce the growth of kelp plants, and damages them by causing them to lose blades, causing fronds to sink, and attracting fish and other predators.

The relationships between light, fouling and growth were examined in an experiment in which juvenile kelp plants were transplanted to the Unit 1 plume and to other areas in which underwater light levels varied {Kelp'Appen-

'T'

~ diz 1, pp. 101-121; ltelp Appondbt 2, Table 11; Kelp Appendix 3, p. 6). A mul-tiple f8&resai0tl of arowth rate (A log lqth in c:JtJ/day), versus irrsdiance (Khal/d) and percet cover by Meabranipora (a bryozoan that is a major fouling organism), explsinsd 99% of the variance in &rOifth in the experi11111t!tal juveUe plants at four locations at different distances from the SONGS Unit 1 dis-charge.

This uperimant suggests vary strongly that decreases in light and increases in fouling vill have a detrilllantal effect on lr.alp growth.

tJnfor-tunately, the relationships 81110118 the thrse factors (liaht, fouliDB end &rowth) are complex, and thia complexity prevets us from aalr.:lna a cOtlfident quanti-tativa prediction. The uncertainty arises because (1) the effects of light and fouling on arowth are confounded, (2) the relstiODship between growth and light is different inshore and at SOK, (3) arowth and light do not always show a consistent relationship, and (4) we cannot predict quantitatively how fouling will thqe at S01t.

(1) tower light vas always associated with greater foulina in this experi11111t!t, and so va cannot tall how 11111ch of the reduction in arowth was caused by aath of these factors. Fouling alone explained 95.3% of the variance in arowth, and light explained* 99.5% of the rlllll4ining variance, a aignificant fraction, so we know light has!.!!!!. affect. Light alone explainS 99.7% of the variance in growth, and fouliDB upla:lna 93.1% of the r~

variance

(;,mich is not a atatiatic:ally significat fraction).

We have, so far, bean unable to aaperata the affects of thaaa two factors upon growth.

(2)

The relation batwaan kelp arowt:h and light in SOK is different from the experimental ralstionehip established inahora. At a given light laval kelp aroww faster in SOK tban it does inshore.

(3) There is one pair of observations in SOK that shove kelp growiDB at ai1111lar rates at different light levels (Annual Report, p. 110, Tabla 4.2).

(4}

Fouling appears to be increesed by an increasing cODcentration of particles in the water, and by turbulece.

We do not know the quantitative relationshipa inVOlved, and we do not have a precise prediction for these two variables under SONGS' operatiOD.

Furthermore, the organillliiS uy 1) behave differently, 2) be a different 1llix of species, and 3) differ in abundance at SOK and inshore.

Thus, we cannot predict the extent of fouling at SOK once SONGS Unite 2 and 3 basin operation.

Ezpenments now underway should help resolve the relationship between light and arowt:h.

In spite of difficulties of interpretation, however, the transplant experimant predicts that lr.alp arowt:h will be reduced when SONGS 2 and 3 are operating. Reduced growth would be expected to (a) reduce the average size of plants, and so reduce kelp biOIII&Sa and cover, and (b) reduce tlia number of lr.alp planta.

We next explore quaatiOtl (b).

Reduced arowth should reduce plant density because death rates of jUVIItlile and sub-adult stages are generally higher than those for adults, and plants would spand loDBer in the high death rate phases. Accord!DB to one set of celculations, this -uld lead to a 70% reductiO!! in the number of plants produced from a cohort of new juvanilaa (ltalp Appedix 2, pp. 13-17). If compensation operation, the reduction could be aa 8111all as 25%.

We cannot place IIUCh reliance on thaaa particular figures because dif-ferent seta of plausible asauaptiona and relatiOtlehipa give us different

r:n

~

-ss-estimates that range from a negligible effect to an even greater than 70%

reduction in abundance (Kelp Appendix 5).

Furthermore, we still have the problems of the confounding effects of fouling, and one pair of observations of similar growth at different light levels in SOK.

No firm qu.antitative prediction can be made about growth and survivor-ship.

(C)

Other factors associated with SONGS (1)

Sedimentatiou Sedimentation appears to reduce the recruitmeot of new plants by smothering them and increasing abrasion.

However, SONGS is expected to have no effect on the sedimentation rate on the bottom at SOK.

(2)

Sea urchins Sea urchius (Lytechinus) have caused a large amount (about 45%) of adult mortality in parts of the bed.

They also appear to intarfere with re-cruitment by grazing on the microscopic and very small stages of kelp.

SONGS will probably increase the amount of particulate organic matter (POC) at SOB:.

Schroeter et al. (Kelp Appeudix 5) show that urchins grow more 1n.abore than offshore, and argue that this was caused by highar POC levels there.

They conjecture that SONGS will tberefora increase urchin populations, and hence grazing prassure, in SOB:.

This seems a reasonable prediction, but we cannot be certain it will occur because other factors (predation, etc.)

also effect tba abundance of sea urchina.

(3)

Toxins lteduced growth and settlement of various organisms in the Unit 1 diecharge plume have led investigators to postulate that tha plume contains small qu.antitiu of toXin(s) - perhaps copper or chlorine.

Southern California Edison claima that Unit 1 releases axtramely small amounts of copper, that copper will be virtually absent from the plumes of Units Z and 3, and that these units will also use little chlorine.

There are no usable data on toxins from SONGS, and we cannot evalueta their possible rola.

This point requires investigation.

(4)

Temperature SONGS ia expected to have very little effect on water temperatures in SOK (a less than 0.5°C average increase, a 1lllllt1muln of a 1 °C increase, and a non-detectable increase over moat of the bed) *

(5)

Nutrients The concentration of nutrients is expected to increase in SOK in surface and mid waters at soma periods of the year.

We have no quantitative prediction of this effect, nor do we know the relationship between nutrient levels and adult plant growth.

This mechanism could lead to greater plant growth (Plankton Appendix 2) *

(D) 0'/uall effacts on the Wp bed The predicted reduction of recruitment, and an increase in mortality, would lead to a reducad dansity of kalp plants in the offshore portion of the bad.

The48 twn effects plus reduced growth of individual plants and greater grazing by urcbina would raduce the &IIIOunt (l>iomass and cover) of kelp in the bed.

Increased midvater nutrients could cause an increase in kelp growth.

We cannot malta a quantitativa eatimste of tha ovarall effects.

{!) Effect* on shrimp in the kelp canopy l!%periments carriad out at various dist.ancu from Unit 1 discharge

lj'1

~ showed that shrimp densities on settling plates vera lower close to the dis-charge.

These spatial differences tended to disappear when SONGS vas not operating. It vas elao show that the death rate of shrimp in experimental containers vas greater closer to the Plant.

The miocheniSlll causing these effects is not known, so no quantitative predictions of the effects of Units 2 and 3 can be made.

Shrimp are important in the diets of various fish species that live in SOl: (ltelp Appendi::l: 5, PP* 12-13) *

-sa-

~

1. Annual loss of mysida From the field s8111Pling program we lcnov hov mysid densities change as one goes offshore.

Several species, constituting most of the mysid popula-tion, are restricted to within 3 or 4 1cm of the shore (Mysid Appendix 1).

Maximum mysid density occurs in the intalce zone.

These data, plus information on the rate of SONGS' intake of water, allow us to calculate how 111any mysids will be taken into SONGS' intakes.

Sampling at Unit l, and labo.ratory studies, suggest that all myaida taken into the cooling system will be killed.

We are much less certain. of the number that vill be killed by the dis-charge plume, which vill entrain about 10 times ita own volume of water.

There are two possible sources of mortality. Firat, *some mysida will die from turbulent shear forces created by the discharging water.

We believe this will be a relatively minor source of mortality.

Second, some mysids vill be carried further offahore in the plume and deposited offshore of their nor1IIBl habitat.

There is as yet no reliable method for predicting the number of mysids dying in this way.

2.

My&id depreaaion (a) Depression caused by intake and diffuser mortality tf mysid mortality 1a of the order calculated in Section 1, we would expect there to be a lowering of mysid density downstream from the Plant.

The extent and depth of the depression depends upon the rate of mixing with water that has not passed through the Plant, and on the ability of surviving myaids to compensate with increased reproduction, growth or survival.

Fj'"1 e:l The probable extent of the depression was estimated using a model that combines a description of water movements and the biology of the mysids (Mysid Appendix 4). The model describes both the ambient current regime and SONGS' plume, and moves mysids about accordingly. It incorporates the natural mortality rate of mysids (as determined from samples) and imposes on this rate the expected SONGS-induced mortality.

The model incorporates 100% intake mortality and 20% mortality in the plume.

(The model assumed that this was caused by turbulent shear. It is more likely that any diffuser losses will be caused by translocation; however, we use the output as an indication of the scale of possible effects.)

The model predicts that, for much of the year, depressions on the order of 50% should exist out to 5 lr.m or more from the Plant, and that lesser depres-sions should extend for more than 10 kn!.

We need to view these predictions with caution.

The model is not a precise description of reality; in particular, it becomes less accurate as it predicts events more distant from the Plane.

Also, the amount of translocation mortality is not known.

llhat the model does tell us is that we can expect to see a measurable depression in mysid density, at least several lr.m long, for much of the year, and it probably indicates the maximum size of the depression that could be caused by these mechanisms.

(b)

Depression caused by an unknown factor The Mysid Study group has data suggesting that Unit l presently causes s depression in mysid density of almost 50% that extends 6 km downstream (Myaid Appendix 3). This is the difference observed in the longshore pattern of abundance between samples taken when the Plant is on, and when it is off. There is statistical support for this claim, but there is a difficulty in that the Plant on" samples \\1ere taken in October, while the "Plant off" samples were taken in spring, and the general level of mysid abundance was greatly different at these two seasons.

Samples are being taken now, while the Plant is off, to resolve this issue.

The Committee feels there is a further problem with these results.

Even if it can be shown statistically that a depTession occurs when the Plant is on, but not when it is off, we know of no mechani~m that is likely to pro-duce such an effect.

(The actual kill via intake and plume mortality would not depress the population for such a distance, and the plume from Unit 1 rarely extends more than 3 lr.m from the Plant.) One suggested mechanism is that organo-chlorine compounds from the Plant adhere to very small particles and settle out over a distance of 6 lr.m.

We have no evidence concerning this mechanism.

If the new studies confirm the existence of this depression, further work will be required on this question.

If indeed there is a depression to 6 km caused by Unit 1, then it may be reasonable to expect that the enormous additional kill rate of Units 2 and 3 will extend the depression to 10 km or so.

Notice, however, that there is no evidence thst the plume from Units 2 and 3 will extend further downcoast than thst from Unit 1. thus there is no certainty that the additional intake and plume losses from Units 2 snd 3 \\10uld extend an already existing depression.

3. Significance of myaid losses Mysid populations are extensive along the coast, and our predictions do not imply that SONGS 'WOuld have a significant effect on the coastal populations.

As stated in the Predictions", we do not expect these effects to have a major

rr

~ impact on. the local popul.atioM of fodde-.: fish, although this ill eutaio.ly a prediction that ve need to chad: when Units 2 and 3 begin operating. ~

1. The evidence that soma zooplanktoo.ic species are restricted close to shore can be found in Plankton Appendix 1. The centers of abundance of the inner nearshore species are in the areas of the intake and diffusers, and these species are therefore subject to grestel: SONGS pressures than other less restricted species.

Some of the zooplankton. restricted to the inner nearshore tend to live closer to the bottom where the longshore cur-cents are slower (MaC Interim Report 1979..02 (II). p. 17), and as a eonaequence their longshore replacement (mixing) rates could be lower than those for other species. In addition, some of the non-rest-.:icted species could be replaced by individuals from farther offshore. All of this would favor the non-rastrictad.epecias in the recovery from SONGS losses and would tend to promote a shift in relative abundenee.

2. Synoptic samples taken in the intake and discharge ports of SONGS Unit 1 diiiiiOIIetrata that few of the withdrawn :ooplenkton oecur in the dis-eharged vaters (MaC Intarilll Report 1979, and Plankton Appsndix 2). Presumably, they are constmed during their journey through the intake conduit by the bantldc organi111111 that live on the inner walls.

'tbeee benthic organi81118 are pursed fro~~~ the cooling system during heat treatvllmt and revarn flow, and become part of the inshore bantbic food chain. the eetilllatee of plankton deneitiea uaed in predictins intake loasee can he found in Plankton Appendix

2.

The eetimate of zooplankton entrainment by diffusere is based on total macrozooplankton (zooplankton sreater than.2 -

in width) plus the lllicro-zooplanktO'llic spseiea Euterpins acutifrons. l!uteriins was included because

'I'

~ it forms a major part of the diets of most fish larvae and some fodder fish in the area.

Using the field samples from 20 dates for macrozooplankton and from 5 dates for Euterpina, the mean concentraeions we~e calculated for dif-ferent positions expected to be affected by diffuser entrainment (Plankton Appendix 2). This estimate of about 4 x 104 metric tons of :ooplankton entrained per year was based on the assumption that equal entrainment occurred at all depths over the full length of the diffusers.

The assumption that 10% of those entrained are killed results in an estimate of 4000 metric tons.

Moat of the zooplankton biomass moved offshore by diffuser entrainment is likely to be eaten by adult and juvenile anchovies, top smelt, and black-smiths.

According to the HRC Fish Group, the blacksmith should inc~ease in abundance because the diffuser ~ip-rap provides new habitat and the diffuser plume provides a continual source of zooplankton. In the absence of SONGS these secondarily entrained. zooplankton would have been available to the sa.a predators and to the late larval stages of the fodder fish Genyonemus and Seriphus.

3.

The diffuser discharges will result in replacement of part of the offshore surface water by a plume consisting of a mixture of nutrient-rich waters from closer to shore and nearer the bottom.

The detailed methods used in estimating the amount of nitrate plus nitrite added to the surface waters, and the conversion of these estimates to estimated phytoplankton production, are explained in Plankton Appendix 3.

SONGS will induce a real net increase over present primary production off San Onofre. First, in surface and mid waters where chlorophyll is high, nutrients are low, suggesting that when nutrients get into the high chlorophyll waters they are taken up rapidly.

Conversely, the presence of deeper waters high in nutrients and low in chlorophyll presumably indicates thst the phyto-plankton there are utilizing nutrients st a lower rate (Plankton Appendix 3).

Therefore the nutrients in the bottom vaters upwelled by the diffusers will be utilized at a far higher rate when they reach the surface.

Second, the waters replacing the entrained waters will also be high in nutrients and low in productivity.

During periods of moderate to strong long-shore currents, entrained water will be replaced primarily from longshore and similar depths.

Under very sluggish conditions most of the entrained waters will come from offshore. In both cases, the water will be rich in nutrients (Plankton Appendix 3).

son BOTT(J{ CXIl!IDNiriES The basie for the predictions can be found in Soft Bottom Co.-unities Appendices 1 and 2;

1. Probable aedimetit effects were estimated by establishing the exist-ing statistical relationships among abundance, diversity and characteristics of the sediments.

Probable changes in the sediments vera estimated (very approximately) from informati~ about the weights of various materials in the SONGS' plumes, from information about water movements, and from information about the settling rates of various classes of materials.

2.

Some 17% of the benthic species at some time rise into the water column and are at risk to entrainment by the intake or the discharging water.

J1 Too little is known about this group to make a firm quantitative estimate of

~

losses, but we expect them to be roughly the same as mysid losses.

We are very uncertain about possible losses of planktonic larvae and th.e potential effects.

This group of plankton is very poorly known.

We do have data showing that the larvae of some intertidal and nearshore species are restricted inshore. Bovever, we cannot estimate losses of benthic larvae because we do not know how to estimate mortality caused by the plume.

Finally, although we know for some rocky bottom species that have been studied, that larval settll!llent far exceeds the number needed to maintain !;he adult popula-tion, ve do not knov if this is always the caae, or if it is true for soft bottoms. If it were, likely raduetions in larval settlement would have no effect on adult numbers.

It is possible that aoms intertidal and shallow vatet species will show reduced adult densities close to SONGS.

Bovever, it seems likely that total

-* --**---*---~~~=- densities will not be significantly reduced, and that any reduction of a particular species will be lllllde up by increased denaity of others.

3.

Thl! enrichment of bottom aedimetits should have virtually no effect on the production of sport and c011111ereial fieh.

Thl! enr:lchlllent. derives from SONGS' killing of organisms in the water column, and so represents a shift of materiel.

The fo.od chains on the soft bottom eventually lead to the 4aliiQ group of sport and commercial fish species as do planktonic food chains; however, there should be some additional losses of this 1114terial aa it passes up the benthic food chain.

HARD BO'l"!C!! CC!!MUNITIES The Hard Benthos Project (Hard Benthos Appendix) hss shown clear dif-ferences between nearshore and offshore communities on the underside of experimental panels, and s~ degree of similarity between the communities on panels and on natural boulders. There is also a correlation between these differenees and turbidity; and the inshore species grow faster than offshore species at high turbidity.

We believe there is no strong evidence that major changes.. will occur in this co=munity.

Several factors prevent us from making quantitative predictions, including the lack of close similarity between experimental panels and the tops of boulders, and the lack of quantitative relationships

'j1 between possible changes and turbidity levels.

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Map 2. Map of the coast near San Onofre showing the cooling systems of SONGS Units 1, 2 and J and the medium to high density areas of kelp measured in December, 1978, within the San Onofre Kelp (SOK) bed.

The boundaries of the areas where the sediments are modified are indicated by dashed linea. The dotted line delimita the area within 1,900 feet of the diffusers aa specified in the Coastal Coam1aaion Permit of February 28, 1974, Page J, ltea c.

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I

APPENDIX F EVACUATION MODEL

APPENDIX F EVACUATION MODEL "Evacuation," used in the context of offsite emergency response in the event of substantial amount of radioactivity release to the atmosphere in a reactor accident, denotes an early and expeditious movement of people to avoid exposure to the passing radioactive cloud and/or to acute ground contamination in the wake of the cloud passage. It should be distinguished from "relocation" which denotes a post-accident response to reduce exposure from long-term ground contamination.

The Reactor Safety Study 1 (RSS) consequence model contains provision for incorporating radiological consequence reduction benefits of public evacuation.

Benefits of a properly planned and expeditiously carried out public evacuation would be well manifested in reduction of acute health effects associated with early exposure; namely, in the number of cases of acute fatality and acute radiation sickness which would require hospitalization.

The evacuation model originally used in the RSS consequence model is described in WASH-1400 1 as well as in NUREG-0340.2 However, the evacuation model which has been used herein is a modified version3 of the RSS model and is, to a certain extent, site-emergency-planning oriented.

The modified version is briefly discussed below.

The model utilizes a circular area with a specified radius (such as a 16-km (10-mi) plume exposure pathway emergency planning Zone (EPZ)), with the reactor at the center. It is assumed that people living within portions of this area would evacuate if an accident should occur involving imminent or actual release of significant quantities of radioactivity to the atmosphere.

Significant atmospheric releases of radioactivity would in general be preceded by one or more hours of warning time (postulated as the time interval between the awareness of impending core melt and the beginning of the release of radioactivity from the containment building).

For the purpose of calculation of radiological exposure, the model assumes that all people who ltve in a fan-shaped area (fanning out from the reactor) within the circular zone, with the downwind direction as its median (i.e., those people who would potentially be under the radioactive cloud that would develop following the release) would leave their residences after a specified amount of delay ttme* and then evacuate.

The delay time is reckoned from the beginning of the warning time and is the sum of the time required by the reactor operators to notify the responsible authorities; the time required by the authorities to interpret the data, decide to evacuate, and direct the people to evacuate; a*nd the time required for the people to mobilize and get underway.

The model assumes that each evacuee would move radially outward in the downwind direction with an average effective speed* (obtained by dividing the zone radius by the average time taken to clear the zone after the delay time), over a fixed distance* from the evacuee's starting point, which is somewhat greater than the zone radius.

This distance is selected to be 24 km (15 mi) when the selected zone radius is 16 km (10 mi).

After reaching the end of the travel distance the evacuee is assumed to receive no further radiation exposure.

Persons who are outside the evacuation radius are assumed to remain in place for seven days prior to relocating, unless remaining for that long a period of time would produce a dose greater than 200 rem to the whole body.

In that case, relocation takes place after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, with a dose appropriate to that time period.

The model incorporates a finite length of the radioactive cloud in the downwind direction, which would be determined by the prodyct of the duration over which the atmospheric release would take place and the average windSpeed during the release. It is assumed that the front and the back of the cloud formed would move with an equal speed, which would be the same as the prevailing windspeed; therefore, its length would remain constant at its initial value.

At any time after the release, the concentration of radioactivity is assumed to be uniform over.the length of the cloud.

If the delay time were less than the warning time, then all evacuees would have a headstart, i.e., the cloud would be trailing behind the evacuees initially.

On the other hand, if the delay time were more than the warning time, then depending on initial locations of the evacuees, there are possibilities that (a) an evacuee will still have a headstart, (b) the cloud would be already overhead when an evacuee starts to leave, or (c) an evacuee would be initially trailing behind the cloud.

However, this initial picture of cloud-people disposition would change as the evacuees travel, depending on the

• Assumed to be constant value for all evacuees.

F-1