U. S. Environmental Protection Agency
    Office of Water Enforcement
        Permits  Division
     Industrial Permits Branch
        Washington, D. C.

         May 1, 1977

               LIST OF FIGURES
No.              Figures             Page

            Decision Train Flow  Chart      ^ ^

                             TABLE OF CONTENTS


1 o   Acknowledgements                                            1

2.0   Introduction                                                 3
      2.1  Background Information                                 J
      2.2  Suggested Uses  of this Technical Manual

3.0   Productive  Demonstration                                   11

      3.1  Introduction                                          11

      3.2  Decision Train                                        11

      3.3  Biotic Category Determinations and  Recommended
             Early  Screening Procedures by  Industry              18

      3.4  How to Select the  Most Appropriate Demonstration
             Type                                                33

      3.5   Type  II  Demonstrations (Representative Important
             Species)                                            34

      3.6   Type  III Low Potential Impact  Determinations          63

      3.7  Other Type  III  Demonstrations  (Biological,
             Engineering, and Other Data)                        64

      3.8  Decision  Criteria                                     65

      3.9  Non-Predictive Demonstrations (Type  I, Absence
             of Prior  Appreciable  harm)                          72

4.0   Definitions  and  Concepts                                   73

           - 1 1 -
          Tables                    Pag(

Sample Table to Summarize          41
Data for  Each Representative
Important Species (RIS)

Thermal Effects  Parameters          42
Applicable to  Aquatic  Organisms
Potentially  Selected  as RIS

Cooling  Water  Characteristics     5 3


                          1.0   Acknowledgements

        This manual represents the efforts of many  who  unselfishly  con-
tributed  their time  and  expertise.  Originally,  specific  assignments
were  delegated to working groups but,  as time  went by,  individuals  in
these  working groups were  asked  to  provide  assistance in other areas.
Therefore,  to simplify the acknowledgements, the following  is a  list
of those  who at  one time or another  contributed to the development  of
this manual:
U.S. Environmental Protection Agency

        Allan Beck,  Narragansett,  Rhode  Island
        William Brungs, Duluth, Minnesota
        Stephen Bugbee, Washington, B.C.
        John  Christian,  Washington, B.C.
        Jeffrey Goodman, Washington, B.C.
        Belbert  Hicks,  Athens, Georgia
        J.  William Jordan,  Washingt9n, B.C.
        J.  H.  McCprmick,  Buluth, Minnesota
        Bonald  Miller,  Narragansett,  Rhode  Island
        Bonald Mount,  Buluth,  Minnesota
        Biane Olsson, Washington, B.C.
        Mark  Pisano, Washington, B.C.
        Jan Prager, Narragansett,  Rhode  Island
        Ronald Preston, Wheeling, West Virginia
        Ronald Raschke, Athens,  Georgia
        Robert Schaffer, Washington,  B.C.
        Eric Schneider, Narragansett,  Rhode  Island
        Lee Tabo, Jr.,  Athens, Georgia
        Bruce Tichenor, Corvallis,  Oregon
        Howard Zar, Chicago,  Illinois
Nuclear Regulatory  Commission

       Harold  Berkson, Bethesda,  Maryland
       Thomas  Cain, Bethesda, Maryland
       Phillip  Cota, Bethesda,  Maryland
       Robert  Geckler,  Rockville,  Maryland
       Bennett  Harless,  Rockville,  Maryland
       Robert  Jaske, Bethesda,  Maryland
       Michael  Masnik  Bethesda,  Maryland
       Robert  Samworth, Bethesda,  Maryland


U.S. Fish and  Wildlife Service

        John Boreman, Ann Arbor, Michigan
        Thomas Edsall, Ann Arbor, Michigan
        Phillip  Goodyear,  Ann Arbor, Michigan
        Roy  Irwin, Ann Arbor, Michigan
        Glen Kinser,  Washington, B.C.
        Mark Maher, Ann Arbor, Michigan
Oak Ridge National Laboratories

        Charles  Cputant,  Oak  Ridge, Tennessee
        Jack  Mattice,  Oak  Ridge, Tennessee
U.S. Energy Research and Development Administration

        Heyward Hamilton,  Washington, B.C.
        W.R. Taylor, Germantown, Maryland
Argonne National Laboratory

        Rajendra Sharma, Argonne,  Illinois

Great Lakes Fishery Commission

        Carlos  Fetterolf, Jr., Ann Arbor, Michigan

                             2.0  INTRODUCTION

                        2.1   Background  Information

2.1.1   Brief History of the  Evolution of this Document

        Prior to  the  enactment  of Public  Law 92-500 [the  Federal Water
Pollution Control Act  Amendments of 1972  (FWPCA)],  the Atomic  Energy
Commission  (AEC) had regulatory authority pursuant to the National
Environmental  Policy Act  of 1969 (NEPA) to impose effluent limitations
on  facilities requiring  an AEC license or permit.

        The FWPCA now requires the Environmental Protection Agency (EPA)
to  establish (for  use in permits  for  the discharge  of pollutants  to
waters of the United States from point sources as defined in the FWPCA
such  as nuclear power plants, etc.)  effluent  limitations for  all pollutants.
The FWPCA provides that nothing under NEPA shall be deemed to authorize
any Federal  agency  to  review  any effluent  limitation  or  other  requirement
established pursuant to  the FWPCA,  or to impose,  as  a condition of any
license  or permit, an  effluent  limitation other than any  such limitation
established pursuant to  FWPCA.

        Pursuant  to  the authority of the  FWPCA, EPA required  applicants
for discharge permits to submit information required by EPA  in order to
establish  effluent limitations in  permits.   Pursuant to the  authority  of
NEPA,  the Nuclear Regulatory Commission (NRC) may require  applicants for
licenses or  permits to  submit information required  by NRC in order to
evaluate and consider the  environmental  impacts of any  actions it  may
take.   Consequently,  the informational  needs  imposed by the  two  agencies
may be similar in the  area  of  impacts on water quality or biota.

        NEPA requires that  all Federal  agencies prepare  detailed environ-
mental  statements on proposed   major  Federal  actions which  can  significantly
affect the  quality of the human environment.   A  principal objective  of
NEPA is  to require  the agency to consider,  in its  decision-making
process, the  environmental impacts of  each proposed major action and the
available  alternative  actions.  Both EPA  and NRC have  responsibilities
pursuant to NEPA regarding  the issuance of  licenses or permits for
nuclear power plants  and certain other facilities.

        In late  1973, the  Chairman of the Council on  Environmental
Quality  (CEQ) wrote  to the Chairman of the then AEC  and  the Administrator
of EPA Suggesting steps that might be taken "to  make the  analysis  of the
water quality impact  of nuclear  power plants  more  effective  and more
meaningful and, at the  same  time, reduce demands for  data being  placed
upon  applicants  for licenses."



        In summary, CEQ suggested that AEC and EPA:

        m  explore mechanisms available  to assure that  applicants'
             environmental  reports to AEC  contain sufficient  data  to
             satisfy EPA requirements on water  quality matters;

        (2)  consider the possibility of preparing a  single impact
             statement to meet AEC's requirements under NEPA  and
             EPA's requirements under FWPCA; and

        (3)  consider the possibility of unified hearings.

        In response to CEQ's suggestions,  AEC (subsequently NRC)  and EPA
developed  the Proposed Second  Memorandum of Understanding regarding
their  perspective  responsibilities  under NEPA FWPCA, which  was
published  in the Federal  Register for  public comment on November 7, 1974
(39 FR 39490), and in final  on December  17,  1975  (40  FR 60115).

        In summary, the Memorandum:

        1.  specified  the statutory authority of both agencies  for
            entering into  the Memorandum.

        2.  Defined those licensing  and  regulatory  activities  to  which
            the  Memorandum  shall be applicable.

        3.  specified  that NRC and EPA will work together to identify
            needed environmental information   for early evaluations
            related to impact from  the  identified activities  on  water
            quality  and biota.

        4.  Provided for EPA  to exercise its  best efforts  to  evaluate
            impacts on  water  quality and biota as far as possible
            in  advance of the issuance  of NRC's  final environmental
            impact statement  for any covered activity,  and specified
            that EPA  and NRC  will  maintain  close working relationships
            during the entire  environmental  review process.

        5.  Specified  that EPA  will issue to the applicant, where  appro-
            priate, in light of substantive  requirements,  a complete
            section 402  permit as far as possible  in  advance  of authoriza-
            tion by the NRC of any commencement of construction or
            issuance by  NRC  of a license or early site  approval, whichever
            is  applicable.*
   See 10 CRF  Part 2,  Appendix A, Paragraph I(c).

        6.  Specified chat EPA and MRC vill consider che feasibiiicy
            of holding combined or concurrent hearings oa EPA's
            proposed section 402 permits and SRC's proposed issuance
            of construction permit* or other activities where

        7.  Rescinded the Memorandum of Understanding Regarding
            loplementation of Certain Complementary Responsibilities
            under the FWPCA and dated January 12, 19, and 22, 1973
            (38 F* 2713).

        As a first step cowards implementing che objectives of che
Memorandum, a series of aeetings between EPA and JfRC took place in late
November 1974..  At chese aeetings it was decided that one of the most
difficult tasks to b* done, and one which should be started first, was
to standardize aquatic biological data requirements to satisfy FWPCA
requirements for EPA and NEPA requirements for MRC.  Technical expert*
representing' the two agencies in the field of aquatic biology held a
series of aeetings in December 1974, formulated aany tentative agree—
aents, and appointed a series of eight working groups.  Each working
group was co-chaired by one representative from each agency.

        On January 28—30, 1975, the- eighc working groups aet in Falls
Church, Virginia, to complete specific writing assignments contributing
to the development of a new guidance manual. Each working group submitted
draft summaries, of their work on che last day of che meeting and final
sianarlas by early March 1975.
        The long process- of piecing1 the products of che eight working
groups together into on* cohesive technical aanual was slowed by key
personnel changes within the agencies and heavy schedules of other
individuals on che working groups.  In spite of che maerous setbacks,
a December 11, 1975, draft was completed and reviewed by key working
group members during January 1976 in Athens, Georgia.  At chis aeecing
it was indicated that several sections still needed revision and others
should be deleted, altogether.  Areas of responsibility were assigned
to willing working group members and this edition of the aanual is che
result of these efforts.

2.1.2   A. Shift of Emphasi*

        In cha course of eh* development of ehis draft, ic beci
apparent to many working group members chat early screening procedures
by industry or chair consultants could somatiaas reveal choaa cypas
of information which would, aot ba necessary to gather la graat datall
ac some sites.  If initial pilot fiald surveys and lltaratura survey*
ravaalad chat, tha site waa oua of low potantlal impact for phytoplankton
for example, it would ba unnacaaaary to conduce datallad studies co
give tha tttonomic identification of every rpaclaa of phytoplankton
in tha vicinity.

2.1.3   Public Availability of 316(a) Demonstrations

        Ic la cha intention of EPA, co aaka tha- tacholcal indorsation
submitted by induatrlaa in accordance with 316(a) available for use
by othar induatrlaar scientists,, and nambars of cha public.  This
will ba dona initially by placing copies of tha demonstration and
supporting document* into tha collection of cha raaponaibla EEA, Ragional
Of flea library.  A. siallar approach U also suggaatad for Stata aganciaa.
In caaaa whara damand for cha daBooatration aatarlala azcaada tha capa-
bility of aa EPA. or Stata agancy library, cha EPA. Ragional Administrator
may alsa subvlc cha materials co tha- national Technical Information
Sarrlca (HTIS) so that cha reports ara avallabla to cha public in
aicrofiche or hard copy fora, ac cha prica of duplication.  Tha EPA
ELagional librarian will ba able to provide detailed information regarding
input and. accasa co th* STIS
        It iJ also noted thac cha Atomic Industrial Forum, Environmental
Scudiaa Project, ha* developed DJTORDM, a data system which will extract
information crom reports submitted by utilities in accordance vich
section* 316(a) and (b)«  Quastion* should ba referred co cha Project at
1747 Pennsylvania Avanua, Washington, D.C. 20006, telephone 202-433-9234.

        Tha Saptember 30, 1974, draft of tha EPA.  316(a) Technical Guidance
*•««•i suggest* two possibilities for predictive  demonstrations:  Type  II
demonstration* (with specific data, requirement* for Rapraaentative
Important Spades (113) and biotic communities) and Typa  III demonstra-
tion*:  (an alternative plan following written concurrences from  EPA).  The
SIC tmgulatory Guide 4.2*. on tha othar hand, gives general guidance and
include* mention of studying a wide spectrum of trophic level*  which
mighe  ba adversaly affected by tha power plane's  operation*.  The net
result of this combination of situation* is chat  power companies have
often  embarked, without tha benefit of appropriate screening or pilot
studies, on large-acala, expansive, Inappropriate studies which supply
aaaaiva amounts of raw data but ara aot necessarily helpful to  regulatory
agencle* in decision-making.
 * JflC Regulatory Guide  4.2,  Preparation  of  Environmental  Reports  Cor
  Nuclear Pover Stations.  July  1976, Revision  02:  102  p.

        Tha decision train suggested by chis manual encourages che
utility co conduce preliminary pilot or screening procedures co decarmine
how detailed the baseline bioclc containi t7 studies should be and co
initiate che appropriate selection of Type II, Type- III, or low potential
impact Typa- III demonstrations.

        Tnis procedure, plus «n increased focus on comparing rationales
dcralopad by eha applicant with dacljlon criteria glvan in chls draft,
r«prt«anca a shift of avphaal* which will hopafully raault in studlaa,
daaonatratiooa, and anvlronamcal raports which aaka aora sanaa and ara
•aaiar to intarprtt.

        In davaloping chis varsion of cha manual, an ••phaals haa
baan placad upon identifying: chos* cypaa of inforaation aoct ralaranc
for dacialon «^n T»y and for dalcting- data r*quiraaanc» which tiava baan
found to b* of llctla uaa in paat 316(a) daclaiona*  3y identifying such
information aaeda by water body type (river, eatuary, Lake, ocean) and
by defining: which araaa need leaa detailed studiaa, this version of the
«^«t"l attempts to discourage the collection, of maacaa of costly,
unnecessary data which aay actually confuse- the Lssua by diverting-
attention from more important information.

        la ehl« regard, it is interesting to note the balance of general
ecoaysteat (baseliner field work.) data, versus the BIS (Laboratory and
literature search) data proposed by this version of the manual.   Past
exparianca suggests chat neither baseline field surveys nor US laboratory
studies alona ware sufficient for predictive demonstrations; some
mixture of cha two is desirable.  Ganaral ecosystem field work, is
necessary co characterize cha environment impacted, co have a basis of
comparison for post operational studies, and to counter possible arguments
that che entire ecosystem has not baan examined.  Laboratory studies on
BIS ara helpful bacausa they offer increased predictive capabilities,
such as how much of the theroal plum* area will preclude reproduction or

                     2.2   Suggested Uses of this
                           Technical Manual by:
2.2.1   The- U.S. Environmental Protect ion Agency

        Ibis version of th» guidance manual, after in-house review
within EPA, will replace the September 30, 1974, draft of che EPA
3 16 (a) Technical Guidance Manual.  The aanual describe* che information
which should be developed and evaluated in connection with making
technical determinations under section 3 16 (a) of the Federal Vater
Pollution Control Act, a* amended., 33 U.S.C. 1251, 1326(4), and 40
CFR Parr 122.

        Most of the "first round1' of tfTOES (National Pollutant Discharge
Elimination System) permits for thermal discharges will have already
been issued, (or at least study plan* will have- been agreed upon by the
applicant and the Regional Administrator)  , by the time, this edition of
the technical «mp"4t is issued.  The determinations or study plans
finalized, to date have been aade on the basis of case-by-cas* technical
decisions made by the Regional Administrator.  These earlier technical
decisions and study plans which were finalized with the approval of the
Regional Administrator or State Director will aoc be negated or otherwise
adversely affected by the issuance- of this newer version of the 316(a)
technical manual.

        The- primary us* seen for this version of the technical aanual
will be- for new sources- and. for the "second round" of 316 (a) deter-
minations- which will come when the first round of permits expire.
capability through the requirement that they continue to review
permits before they are issued.

        Since- those States which have the permit program have
essentially the same- responsibilities as EPA, it follows that these.
States may find this technical ••""• 1 useful in the- same, manner that
the Regional Administrators of EPA. f fiad it useful.  On the other
hand, just as the Regional Administrators are not rigidly bound by the
contents of this document, neither are the State Directors.  It is suggest«d
that those. States which desire to administer their 316(a) program in
a way different from that which is proposed here, first discuss these
differences with the Regional Administrators so that common agreements
can be reached and applicants can be- assured that their 316(a)  study
designs will b« acceptable to both the State and EPA.

        The applicant should also be aware that in general one or more
State permit program, staff have been, designated as 316 coordinators.
It is suggested that applicants considering 316(a) demonstrations
contact these- individuals at an early date to discuss potential
problems and available data.

2.2.3   The. Nuclear Regulatory Commission

        The- Nuclear Regulatory Commission (NRC) tentatively plans
to incorporate- this 316(a) manual and the separate 316(b) manual with
futur* drafts of NRC Regulatory Guide- 4.2. The contents of these manuals
would form- the basis for aquatic ecology data, requirements.  Just
how the- manuals will be- incorporated has not yet been decided, but
one- possibility discussed would be to include the 316(a) and 316(b)
manuals in their entirety as appendices to future editions of NRC
Regulatory Guide: 4.2.  There has also been some discussion of using
parts of these manuals in future editions of NRC Regulatory Guide
4.7* and documents to b* generated by the NRC coordinated State/Federal
Siting Working Group.

2.1.A.   The U.S. Tish and Wildlife Service, Department of Interior

        Th» Fish and Wildlife Service (TVS) is mandated by the Fish
and wildlife Coordination Act (46 Stat. 401, as amended; 16 O.S.C.
661, ec seq.), th* Eadaagered Species Act of 1973, and other asso-
ciated Acts, to coordinate review* with the. appropriate Federal
regulatory agencies on projects that will have impact on fish and
wildlife communities.  These, guidelines will provide a basis for
coordination among FW5, EPA, NRC, and other agencies involved in
* NRC Regulatory Guide 4.7, General Site Suitability Criteria for
  Nuclear Power Stations. November 1975, Revision t2: 32 p.

che 316(A) review process by representing a common understanding of
the decision criteria agreed upon which cb« 316(a) variance will be
based and, therefore, upon which che appropriate regulatory agency
should be. advised*
2.2.5   Other federal Agencies

        Although in no way bound by this document, other Federal
agencies may find it useful as a source of information.  For example,
che national Marine- Fisheries Service (XKFS) of the Department of
Commerce has similar concerns and responsibilities as che FWS in che
Federal regulatory review process.  The NMFS was originally che
Bureau of Commercial Fisheries which, together with che Bureau of
Sport Fisheries ind Wildlife (now FWS), constituted che old Fish and
Wildlife Service in che Department of Interior (as referred to in the
Fish and Wildlife Coordination Act).  Reorganization Plan Ho. 4, which
transferred che Bureau of Connerlcial Fisheries to che- Department of
Commerce, also transferred all associated responsibilities.  Principle
concerns of »CFS are marine- and anadromous fish, as well as inland
commercial fish,  the FWS, by contrast, has a parallel responsibility
in the fisheries aspect, but has an additional responsibility for
aquatic waterfowl (both fresh water and marine) in the. 316(a.) review

2.2.6   The- Electric Power Industry and Consulting: Organizations

        For each individual site, applicants for 316(a) or 316(b)
determinations should discuss the- contents of this manual wich the
lead HPDES Permit Program Agency (either the EPA. Regional Administrator
or the State Director) to determine, the applicability of che manual's
recommendations to chat site*  This document will serve as a starting
point for discussion* leading to a written concurrence between the applicant
and the Regional Administrator/Director on individual study plans which
will satisfy the requirements of both PL 92-300 and che aquatic ecology
sections) of NZPs>.

                     3.0    PREDICTIVE DEMONSTRATIONS

                                                         DP AFT
                           3.1    Introduction            UJX/VT 1

        Predictive studies and associated demonstrations  representing
the best estimate of "what will  happen"  are  appropriate for 316(a)
demonstrations  for:

        1.  New sources  not  yet discharging;

        2.  Facilities  discharging into  waters which,  during
            effluent  for a sufficient  period of time  to allow
            evaluation  of the effects of the  effluent;

        3.  Facilities discharging  into  waters which,  during
            the  period  of the  applicant's prior  thermal  discharge,
            were so despoiled as to  preclude  evaluation of the
            effects  of the thermal  discharge on  species  of shell-
            fish, fish  and wildlife;  and

        4.  Major changes in the facilities  operational mode.

        The two  most detailed  baseline  aquatic ecology studies done  for
NRC  under  NEPA are done two years before  a nuclear plant  becomes opera-
tional. All  studies done for  316(a)  demonstrations during this  time  frame
are therefore  predictive  in nature.   The  regulations  (see 40 CFR Part 122)
published  by  EPA provided for two possible types  of predictive 216(a)
demonstrations:   Protection of Representative Important Species (Type  II)
and Alternative Demonstrations,  with  the written  concurrence  of the
Regional  Administrator  or State Director (Type  III).    This section provides
explanations  of  these  demonstration  types,  details  the  decision train and
decision flow chart,  and recommends  early  screening  procedures helpful  in
choosing  the  most appropriate demonstration type.

                          3.2    Decision  Train
        This section provides a flow  chart and  narrative summary  of the
recommended decision  train.
3.2.1   Flowchart

        The  flow chart  identified as Figure  1. is a summary  of the
recommended sequence of events leading to the  decision.  The  following
is an  explanation of  abbreviations  and  terms used in  the  flow chart:

                                                             FIGURE 1.  DECISION TRAIN FLOW CHART
           l»fo»a>atla« avall«a>|aj
           ia  !•
  I)  far aach alotlc
  u^altMC or *ot CM •!*• I*
  uf  low pot*«tta|
 1) A
            Ur Mty
         »r woik »*c*a
          Appllcant    -•              i industrial Raprasantatlva
                                       Applying for EPA and MRC
                                       Parolts and Llcansas

          Director                     Director of cha Stata NPDES
                                       Parole Program

          FTSA.	Far Fiald Study Area

          RA  •                        . Raglonal Administrator, SPA.

          MS             "'  •'         Rapraaantativa Important

3.2.1   Dacision Train Harrativ*

        Tha decision train (saquanea of avants laadiog co «. decision)
IIscad, tiara 1* dasignad a« ganaral guldanca for both tha applicant and
tha cafTilacorr afanclaa:

        1.  Bafora daaignlnf aqoaclc •coLofj scxidla>» cba applicant
            consult* vleh cha Rafioual ktim-i n1 itracor/Dlractor* co
            varlfy cha appllcabilicy of thl* cachnical manna I for
            satisfying tharmal pluact affacts (316(a) and affluanc
            guldallaaa) raquiramanta undar PL 92-500.  If cha
            Rational Adalnistrator/Diractor spaclflas an altarnatlva
            or aodlfiad rarsiem of this aanual, cha applicant should
            utiliza ic.  If Cha Rational Adalnlstrator/Diractor
            Jpaclfla* using this cachnical aanual as a gulda, cha
            applicant goaa to th« aaocc scap.

        2.  Th* applicant rasds saction 3.3 of this aanual to
            datarmlna what biological data raqulroMncs ara aacasaary
            for aarly scraanlag dacatmlnaclons such as dafialng low
            potential iapacc araas.

* SOTI;  Thai Rational Administrator aakaa 316 (a) datarmlnatioaa for EPA
         laauad permits* tAlla tha Stata Olractor aakaa such datarmlna-
         doas for parmtta issuad by Statas with EPA, approvad parmlc
         protravs.  Such Stata paralts, hovrrar, ara subjact  to EPA
         rarlaw.  It Is charafora suggestad chat in tha casa of 316(a)
         dataralnatlons aada by a Stata Diractor, aithar tha Olractor or
         tha applicant kaaps tha. Ragional Adsdnlstracor informad at
         critical scapa in tha procass to croid tha possibility of
         ultlaata dlsapproral by EPA of a Stata parvlt or dataralnatlon
         which could hara baan avoidad by bactar covmunicatlon chroughouc
         tha procass.

3.  Th* applicant contacts th* appropriate Regional Director of
    the U.S. Fish and Wildlife Service, representatives of the
    National Marine Fisheries Service, and of the States, to
    determine if there are any threatened or endangered species
    that may be affected by the proposed facility's discharge.

4.  Th* applicant gathers existing literature and field data
    from previous studies by th* company, resource agencies,
    academic institutions, and other researchers.

5.  Th* applicant determines whether or aot enough information
    is available to summarize in. writing:

    a»  For each biotic category, whether or aot the
        site is on* of low potential impact.

    b»  A. plan for any additional studies or wort
        necessary to complete the demonstration.

    If aor* information is necessary, the information should
    be gathered through relatively brief "pilot" field

6.  Applicant submits the summaries to the Regional Administra-

7.  If th* Regional Administrator/Director determine* thac
    that sit* is on* of low potential impact for all biotic
    categories, th* applicant may choose the new "short
    form" demonstration type, th* Low Potential Impact Type
    III demonstration detailed in section 3.6; if aot, the
    applicant chooses between Type II and Type III demonstra-

8.  Thos* applicants eligible for the low potential impact
    demonstrations gather any additional information necessary,
    complete relatively brief biotic category rationales, and
    susmmrii* them into on* "master" ecosystem rationale.

    If that proposed discharge will a**t State water quality
    standards, th* additional field studies necessary will
    not b* extensive.  Th* primary information that needs to
    be g*n*rated is simply that which is enough to satisfy
    th* biotic category, resource zone, and master rationale
    criteria in section 3.8.  On* year's qualitative "pilot"
    field studies should be enough to generate enough
    information to complete th* biotic category, resource
    son*, and master rationale.  The applicant can then
    complete physical studies comparable to those in
    section 3.5.3 and proceed directly to step 19 below.

10.  Applicants whose sites do noc qualify for the above
     considerations will ordinarily select ch« Typa II
     demonstration or a Type III demonstration of siailar
     comprehensiveness.  Applicants selecting a type III
     demonstration should carefully read section 3.7 in order
     to gain a general understanding of the detail necessary
     for studies to be considered acceptable.

11.  Those applicants selecting a Type II demonstration first
     meet with the Regional Administrator/Director to discuss
     selection of RIS and define che far field study area..
     If the regulatory agency has reached any tentative
     decisions regarding an allowable mixing zone (see
     section 3.3.3), these decisions should be discussed and
     understood by both parries.  These decisions may be
     reviewed following completion of the demonstration.

     If the regulatory agency and the applicant reach an
     early agreement about the selection of RIS and the
     designation of the far field study area, the applicant
     nay move on to the next step. If aot, the regulatory
     agency aay request that the applicant assist in the
     selection of RIS by doing studies and giving written
     justification for che proposed far field study area.

12.  The- Regional Administrator/Director checks with the
     Regional Director of the FWS and rtpresentatives of the
     *US and States to make sum the study plan includes
     appropriate consideration of threatened or endangered
     speclea as well as other fish and wildlife resources.

L3.  The Regional Administrator/Director provides the applicant
     with written recognition of the specific plan for
     completing the demonstration, including delineations of
     the US far field study area, and threatened or endangered

14.  Applicant completes field and literature work required
     to finish blotic category rationales and writes the
     rationales in accordance with section 3.5.1.

L5.  Applicant completes literature and laboratory studies
     necessary to generate information for the RIS rationale,
     and develops the rationale as suggested in section

16.  Applicant develops engineering and hydrological data
     outlined in section 3.5.3.

17.  Applicant combine* Che information on engineering and
     bydrological data with Che RIS and biotic category
     rationale* into on* "Master" Ecosystem Rationale, aa
     described in section 3.5.4.

18.  Applicant arranges the rationales and other information
     in Che format suggested in section 3.5.5.

19.  Applicant submits demonstration to the Regional

20.  The Regional Administrator/Director:

     Review* che demonstration co see chat '
23.  The Regional Administrator/Director studies the
     RIS information eo see if it supports ch« conclusions
     in the Representative Important Species Rationale.
     If ic does, the rationale is studied in relationship
     to the decision criteria given in section 3.3.2.
     If Che decision criteria are met, the Regional
     Administrator/Director will proceed to the next

24.  The- Regional Administrator/Director studies as a
     composite the biocic category rationales, the
     Representative Important Species Rationale, the
     resource zones impacted, and the engineering and
     hydrological data to see if they provide justifica-
     tion for the conclusions reached in the aastar
     rationale.  If they do and chere is not strong
     contrary evidence from other sources, the Regional
     Administrator/Director will proceed co the next

IS.  The Regional Administrator/Director studies the
     aaster rationale in relationship to all other
     available data, considers the overall decision
     criteria in section 3.3.3, and determines if the
     316 (a)  demonstration has. been successfully oade.
     Following discussions with technical experts on
     his staff as well as those, from the Fish and
     Wildlife Service and other agencies required by
     lav to be- consulted, the Regional Administrator/
     Director oalces the. final decision.

     If the Regional Administrator/Director concludes
     that the suemtary rationale is convincing, it is
     supported sufficiently by the other sections of
     the demonseracion, and is not convincingly
     negated by outside evidence, the applicant's
     316(a)  demonstretion is successful.  The applicant
     has demonstrated that the proposed thermal discharge
     to navigable nmters will be acceptable under
     PL 92-500 (for section 316(a) and effluent

         3.3   Biotic Category Determinations and Recommended
               Earlj Screening Procedures by Industry
        It it recommended that applicants conduct pilot field surveys
and literature searches before embarking upon tussive, comprehensive,
baseline, field sapling-.  These, initial studies, vill often be sufficient
to determine whether or noc the site is one of low potential lapact for
individual biotic categories and to determine what additional studies
vill be required to develop biotic category rationales responsive co
the decision criteria, listed, in this section..

        The applicant should first read this section, chen execute the
initial piloc field surveys and literature searches in. such a manner
that they identify those biotic categories for which the site aay b*
considered a lov potential impact area.

        It should b* noted, here that section provides a
discussion of why the data, requirements proposed in this section are
useful to regulatory agencies in the 316(a) decision-making process.

        Identification of taxa in the various biotia categories should
be to che species level for the HIS organisms and no less than family
level for all others that are listed.
3.3.1   Phytoplankton   Decision Criteria.
              The phytoplankton section of che 316(a) demonstration will
    be judged successful if the applicant can show that the site is a
    low potential impact area for phytoplankton.  For other sices, che
    phytoplankton section of che 316(a) demonstration will be judged
    successful only if che applicant can demonstrate that:

              1.  A shift toward* nuisance species of phytoplankton
                  la not likely to occur;

              2.  There is little likelihood chat the discharge will
                  alter che indigenous community from a decrical to
                  a phytoplankton baaed system; and

              3.  Appreciable harm to the balanced indigenous popula-
                  tion is not likely to occur as a result of phyto-
                  plankton community changes caused by the heated
                  discharge.   Low Potential lapact Areas for Phytoplankcon (Open Ocean and
              Most Riverine Ecosystems).

              Areas of low potential impact for phytoplankton are defined
    as open ocean areas or systems in which phytoplankton is not che food
    chain base.  Ecosystems in which the food web is based on decrical

    material, e.g., embaymencs bordered by mangrove swamps, sale marshes,
    fresh water swamps, and taosc rivers and scream*, are in this category.

              The area will noc be considered one of lov potential impact
    if preliminary literature review and/or abbreviated "pilot" field
    studies reveal chat:

              1.  The- phytoplankcon contribute a substantial amount of
                  the- primary phocoaynchecic activity supporting che

              2.  A shift toward* nuisance specie* nay be encouraged;

              3.  Operation of the discharge may altar che communicy
                  fro0 a decrlcal co a phycoplankcon based system.

    3 .3 .1.3   Study Requirements for Areas ttoe Classified as Low
              Pocencial Iapace (Some Lacustrine. Escuarina. and
              Possibly Oeher Mater Body Types).

              The applicant is noc requested specifically co conduce
    detailed caxonomic scudie* of che phycoplankcon, buc inforaacion pro-
    vided in che demonstration should be adequate to characterize the
    presence, and abundance of pollution toleranc and nuisance fora* as
    well a* co provide baaeline information abouc the phycoplankcon
    community a* a whole.  The parcicular power plane sice and aquatic
    system plu* historical information will dictate the extent of
    caxonomic work required.  In some situations only a few specie* or
    major caxonomic groups (e.g., specie* comprising >5S of total) will
    have to be identified and counced, where** in other situations che
    idencification and counting of several species or najor groups nay
    be required.

              The- experimencal design should be appropriate to determine
    the general characteristics of the phycoplankcon communicy within
    che ancire primary scudy are*.  Sampling outsida che primary study
    are* should be- done ac location* mo*c appropriate to generate data
    typical of che far field scudy area.  Sample replication should be
    adequace eo decermine precision of che daca collected and to
    conduce appropriate scaciacical cases.

              Samtple* should be- taken wlch appropriate gear a* described
    in eh* EPA Biologic*! Mmcnoda Manual.*  Plankcon nets are of limited
    value since many organism* pas* through them.  In certain case* where
*  Biological Field and Uboracory Slechoda (EPA-67Q/4-73-001) .

    extensive stapling is deemed accessary, it aay be possible co use
    an indirect chemical method co assess seasonal or spatial phyto—
    plankton fluctuation*.

              la «o*t case* th« study should determine th« standing
    crop of phytoplankton at periods ranging fro* seasonal to bi-monchly
    depending on th« available information.  Ac a ainlaum, che data
    collected should include:

              1.  The standing crop* of organisms per volume of

              2.  Identification of numerically dominant :aza
                  (i.e., SZ or aore by auaber) and nuisance
                  organism; and

              3.  Delineation of the euphotic zone, preferably
                  vita a submersible photometer.

3.3.2.   Zooplankton and Maroplankton   Decision Criteria.

              The rooplankton and aeroplankton section of the 315(a)
    demonstration vill be judged successful if the applicant can show
    chat the site is a low potential, impact area for cheser organisms,
    or that:

              1.  Changes) in the rooplankton and aeroplankton
                  community in the priaary study area that nay
                  b« caused by the heated discharge will not
                  result in appreciable harm to the balanced
                  indigenous fish and shellfish population.

              2.  The- heated discharge Ls not likely co alter the
                  standing crop, relative abundance, vith respect
                  to natural population fluctuations in the far
                  field study area from chose values typical of
                  the receiving water body segment prior co plant

              3.  The thermal plume does not constitute a lethal
                  barrier to the free movement (drift) of zoo-
                  plankton and meroplankton.   Lov Potential Impact Areas for Zooplankton and Meroolankton.

              Areas of lov potential impact for zooplankton and aeroplankcon
    are defined as chose characterized by lov concentrations of commercially
    important species, rare and endangered species, and/or chose forms chac are

 Important components of che food veb or where ch* cheraal discharge
 vlll affect a relatively small proportioa of ch« receiving water

           Nose estuarlne area* vlll not be conaidered area* of Lov
 pocencial lapact for tooplankton and aeroplankton.  However, where
 a logarithmic gradient of zooplankton and meroplankton abundance
 •rises, choae area* ac Che lowest level of abundance may be recog-
 nized a* low potential Impact areas ac the discretion of the
 Regional Administrator.

           If preliminary 316(a) studies indicate that the area is
 on* of Lov potential Impact, no further 316(a)  studies are accessary.
 la this case the applicant need provide only a narrative discussion
 Justifying tha conclusion char che area is one of low potential

 3 .3 .2 .3   Study Requirements for Other Areas.

           For those facilities not sited in  low potential impact
 areas, the applicant should describe the qualitative and quantitative
 characteristics of the zooplankton and oeroplankton populations.  The
 data should include:

           1.  Standing crop estimate*;

           Z.  Relative abundance* of the taxa present;.

           3.  S«a*onal variation* in the abundance and distributions
               of che various taza encountered;  and

           4-.  The dial, and tidal change* in  the depth distribution.

           The experimental design should be appropriate to determine
 the general characteristics of zooplankton and oaroplankton within
 che entire, primary study area.  Sampling in  the far field study area
 should be done in locations oost appropriate to generate data typical
 of the remainder of the far field study area.  The AU Sourcebook*
 provide* information related to the choice of sampling methods.
 Sample replication should be adequate to determine precision of che
 data collected and to conduce appropriate statistical tests.

           If the applicant believes on the basis of the data collected
 that the zooplankton and neroplankton criteria can be net, the conceptual
 framework upon which the conclusion is based and corresponding data
 analysis «ust be included in the zooplankton and aeroplankton rationale
 of the 316(a) demonstration.  For a further discussion of information
 requirements for aeroplankton, see section
Atomic Industrial Fonsi, Sourcebook:  "Environmental Impact Monitoring
of Xucltar Power Plants," August 1974.


3.3.3   Habicac Formers   Decision Crietria.

              The habitat foraers section of a 315(a)  demonstration
    will be Judged successful if  the applicant can show chat  che
    sic* is a low potential iapacc arta 'or habicat foraers.   For
    ocher sites, the section will be Judged successful if  the applicant
    can demonstrate chac:

              1,  The heated discharge will noc result in  any
                  deterioration of the habicac foraers community
                  or chac no appreciable harts co che balanced
                  indigenous populacion will resulc froa such

              2.  the heated discharge will noc have an adverse
                  iapacc on chreacened or endangered species  as
                  a resulc of iapacc upon habicac foraers.

              Any probable thermal elimination of habicac  foraers  from
    che astuarlne or aarine environaencs or cheir contiguous  wetlands
    constitutes a basis for denial.  Similarly, a basis for denial
    exlscs if important fish, shellfish, or wildlife are cheraslly
    excluded fro* che use of the  habicac.

    3 .3.3.Z   Low Potential Impact Areas.

              la soa* situations, the; aquatic envlroomenc  at  che pro-
    posed sice- will be devoid of  habicac foraers.  This condition  oay
    be caused by low levels of nucriencs, inadequate lighc penetration,
    sedimentation, scouring screasi velocities, substrate character,  or
    toxic natarlals.  Under such  conditions che site nay be considered
    a low potential impact ares.   However, if there is sone possibility
    che limiting factors (especially man-caused limictag factors)  aay
    be relieved and habitat Corners aay be established wichin che  area,
    che- applicant will be required co denonscrace chac che heaced
    discharge would noc restrict  re-escablisheienc.  Those  sices where
    Cher* is a possibility chac che power plane will impact a
    threatened, or endangered species through adverse impacts  on
    habitat toners will noc be considered low potential iapacc areas.

    3 «3 .3 .3   Study Requirements  for Other Areas Hoc Classified as
                  Potential Impact.
              For areas chac do noc qualify as low potential lapact
    areas,  the applicant should provide the following information:

              1.   Regional, sice location map and a scaled aerial
                  map shoving the distribution of habitat fonaers
                  in the region near the proposed site.   The

                  aerial sap should include the primary and far field
                  study areas.  Wh«n available, aerial map* shovlag
                  historical changes in the distribution of habitat
                  formers should be provided.

              2.  List of dominant spaciaa of habitac forming macro—
                  phytes, macroalgae, shellfish, corals, and sponges.

              3.  Standing crop estimate* of the dominant species  in
                  cernj of dry weight of organic natter per unit area.
                  These estimate* should be aade at a alainum frequency
                  of quarterly for on* year.

              4.  Identification of chose species of fish which are
                  dominant species or threatened or endangered species
                  and are dependent upon the existence of the habitat
                  formers for protection or for use as feeding areas.
                  For such species (which are aot considered elsewhere
                  in the. 316(a) demonstration) , the applicant should
                  provide quantitative abundance estimates.

                  The experimental design should be appropriate to
                  determine the. general characteristics of the habitat
                  former community within the entire primary study area.
                  Sampling outside the primary study area should be
                  dona in locations most appropriate to generate data
                  typical of the remainder of the far field study area.
                  Sample replication should be adequate co determine
                  the precision of the data generated and to conduct
                  appropriate statistical tests.
3.3.4   Shellfiah/Mecroinvertebratea   Decision Criteria.

              The- shellfish/macroinvertebrates section of a 316(a)  demon-
    stration vill be judged successful if the applicant can demonstrate
    that no appreciable harm to the balanced indigenous population will
    occur as a result of macroinvertebrate community changes caused by
    the heated discharge:.  For areas classified as ones of low potential
    Impact for shellfish/macroinvertebrates, relatively little new field
    work may be required.  Decision criteria related to individual para-
    meters are discussed as follow*:

              1.  Standing. Crop.  Reductions in the standing crop of
                  shellfish and macroinvertebratea may be cause for
                  denial of a 316(a) waiver unless the applicant can
                  show that such reductions caused no appreciable
                  harm to balanced indigenous populations within che
                  water body segment.

2.  Coammnity Structure.  Reductions in the components of
    diversity may b« cause for che denial of a 316(a)
    waiver unless che applicant can shov chac che critical
    functions (defined la section 3.3.3.) of the macro in-
    vertebrate fauna are being maintained in the water
    body segment aa they existed prior to the introduction
    of heat.

    Generally, with the present state of knowledge it Is
    impossible to state what effect a certain percentage
    of change in the components of diversity will have on
    functional integrity of the system, specifically the
    maintenance of a balanced indigenous population.
    From a generic standpoint, a aajor difficulty relates
    to the- fact chac the species richness of che aacro—
    inverrebrate fauna varies considerably in different
    systems and that the effects of a given level or
    percentage of change sight be a function of che level
    of diversity extant prior to the introduction of heac

    From a decision standpoint, actual or predicted
    reductions in diversity could serve primarily as an
    indication that the system is or will be stressed.
    Because of che- difficulty in predicting changes with
    any degree of accuracy, this parameter could serve as
    a decision tool only in cases where the actual changes
    resulting from plant operation can be enumerated and
    reasonably applied to che- proposed site.

3.  Drift.  The discharge of cooling water equal to 30Z or
    more of the 7-day, 10-year low flow of a river or
    stream would be cause for concern and possible
    rejection of a 316(a) waiver unless che applicant can
    show that:

    1)  Invertebrates do not serve as a aajor forage
        for til* fisheries,

    2)  Food is not a factor limiting fish production
        in the. water body segment, or

    3)  Drifting invertebrate fauna is not haraed by
        passage through the thermal plume.

4.  Critical Functions (Estuaries).  Areas which serve as
    spawning and nursery sites for important shellfish
    and/or macroinvertabrate fauna are considered as zero
    allowable impact areas and will be excluded from

              consideration for the discharge of wa.sc* heat.  Planes
              sited in locations which would impact ch«s« critical
              functions will aot be eligible for a 316(a) waiver.
              Hose estuarine sitas will fall into this category.   Low Potantial lapace Araas for Shellfish/Macroiavartabratas.

          A. low potential lapace area, for shellfish/macroinvertebrate
fauna is defined as an area which, within cha primary and far fiald
study araas, can meet cha following requirements:

          1.  ShalLfish/macroinvertebrate spacias of axiscing or
              poeaneial commercial value do aoc occur at cha sita.
              Ibis requirement can be met if cha applicant can
              show that cha occurranca of such spacias is

          2.  Shallfish/aacroinvartabratas do aoc serve as important
              components of tha aquatic community at cha sita.

          3.  Thraatanad or andangarad spacias of shallfish/macro—
              invartabracas do not occur at tha sita.

          4-.  Tha standing crop of shallf ish/macroinvartabratas at
              thai tiaa of maximum abundanca is lasa than ona gran
              asb-fraa dry weight par squara meter*

          5.  Tha- sita doas aot sarva as a spawning or aursary araa
              for tha spacias in 1, 2, or 3 abova.

3 .3 .4.3   Study Raquiraaants for Othar Araas.

          L.  Saaoling Dasign.  Tha arpariaantal dasign should ba
              appropriate to dataralna tha ganaral characteristics
              of. the shellfish/macroiavartabrata coaomnity within
              the entire prlaary study araa.  Sampling outside the
              pria^ry study area should be done in locations most
              appropriate to generate data typical of the remainder
              of the far field study area.  Saaple replication and
              collection frequency should be adequate to determine
              the precision, of the data generated and to conduct
              appropriate statistical tests.

              At a iiin^Jitai, samples should be taken quarterly for
              one year.  Hoverer, the actual periods selected
              should be keyed to known information on the seasonal
              occurrence of Important forage species, rare and
              endangered species, and species of commercial
              importance.  Sampling for these speciss must occur

when vulnerable life 9cages are in the area.  If,
because of ch« cransicory nature of such species
and ch«ir various lift stages, it is not possible
co include ch«m in a quarterly program or, if Cher*
is a complex of species whose timing in the area, is
unknown, then the frequency of sampling will have
co be. increased.  For che beachic coapoaenc of the
shellf ish/aacroinvertebrates, community sampling
stations should be- selected for each major substrate
type wichin che primary study ares..  Similar stations
should be- selected in che far field study area so
chat che relative importance of che two regions may
be compared.  Where appropriate» chese stations
should also be used Cor sampling che aocile portion
of the shellfish/macroinvertebrate community.

Sampling Methods.  The applicant should use trawls,
crapping, or aetting techniques which are standard
for che types and life stages of shellf is h/aacro—
invertebrates found in che study arcs,.

I of grata c ion Requirements .  The applicant should
qualitatively enumerate as thoroughly as possible
eh* species of shellfish/macroinvertebrate* in-
habiting che impact area and adjacent environments.
For commercial species, important forage- species,
and threatened or endangered species information
should be provided on their status in the area.
(permanent or transient)r seasonal timing of
presence (if applicable), and che life stages
present including aaroplankton.  In addition, che
applicant should describe che importance of che
area for che critical functions of reproduction
and early development.  In cases where che dis-
charge will potentially impact a highly productive
shellfish/macroinvercebrata fauna, the applicant
should provide quantitative estimates of che
shellfish/macroinvertebrace standing crop.  Such
sites include estuaries, shallow nonflactuating
reservoirs, salmoald rivers, and open coastal
sites which hare characteristics similar co
estuarlne sites.  However, the applicant should
recognize chat the level of effort is based on
che area impacted and that sampling of che
benthic component of che shellfisb/aacroinvertebrate

fauna would be minimal in the case of a sice having
sufficient depth chat che plume does aoc reach the
bottom.  Many deep fluctuating reservoirs, as typified
by some in che TVA system, have depauperate benthic
fauna and will require a ••<«<«•«• amount of description
information to document chose characteristics.  In ch*
case of shallow aoa-fluccoating reservoirs  typified
by Lakes Marlon and Moultrle in South Carolina, which
have an abundant and diverse benthic fauna, che appli-
cant should conduct detailed studies.

Other parameters which should be evaluated in the
study include:

A.  Standing crop.  The standing crop of the various
    species should be estimated in terms of numbers
    and biomass per square aeter for both the
    primary and far field study areas.  The biomass
    estimate should be expressed as grams ash-free
    dry weight per square neter.

B.  Community structure.  The community structure
    should be evaluated in terms of:

    1)   the. number of species per sample,

    Z)   the- lumber of individuals for each species
        in. each sample,

    3)   th* total number of species in che study
        areas, and, when appropriate,

    4)   the age structure of the species in each

    Although it may be impossible to collect all
    species in the study areas, the applicant should
    maker a conscious effort to augment che quantitative
    sample data with qualitative sampling adequate to
    obtain a reasonably complete list of taxa.

C.  Drift.  If a riverine sice is being examined, che
    applicant must estimate the quantity and composi-
    tion of the shellfish/macrolnvertebrate biota which
    drift past and will be entrained into the thermal
    plume.  The. applicant should estimate the number and
    biomass of drift organisms per linear aeter of river
    cross section.  Sample replication and collection
    frequency should be adequate co determine che precision
    of the data generated and to conduct appropriate
    statistical tests. In addition, the applicant should
    enumerate chose species which represent five percent

                      or sore of the total number or biomass of organisms
                      comprising che drift,  where appropriate, che
                      applicant may conduct in sieu drift studies at
                      an existing facility to determine whether the
                      common indigenous macroinvertebrates can survive
                      passage through the plume.  These data may be
                      useful for projecting the effects of che plume at
                      the proposed site.

              4.  Data Presentation.  The applicant should provide a
                  scaled substata map which includes the primary and
                  far field study areas.  At least one map should be
                  provided which shows che anticipated outer limlcs of
                  che thermal plume to che Z C isotherm.  In addition,
                  the applicant should provide maps shoving che isotherms
                  as they will exist along the bottom for che conditions
                  of maximum and •ninlnHim ambient water temperatures,

                  In the case- of estuariss, the applicant should provide
                  maps showing the relationship of the predicted plume
                  to spawning areas, nursery areas, and migration routes
                  for che various life stages of commercial species,
                  threatened or endangered species, forage species, and
                  species that are otherwise important to che functioning
                  of the system.

                  The applicant, should thoroughly summarize the data
                  using summary tables and graphics and report the raw
                  data in a separate bound appendix.  The applicant should
                  then provide a narrative evaluation and interpretation
                  of the data which explains why, in che judgment of che
                  applicant, the impacts are sufficiently inconsequential
                  that "the protection and propagation of a balanced
                  indigenous population of shellfish, fish, and wildlife
                  in and on the body of water will be assured."
3.3.5   Fish   Decision Criteria.

              The fish section of a 316(a)  demonstration will be judged
    successful if the applicant can, demonstrate that the site qualifies as
    a low potential Impact area for fish.  For other sites, the fish
    section of a 316(a) demonstration will be judged successful if the
    applicant can prove that fish communities will not suffer appreciable
    harm from:


          1.  Diricc or Indirtcc mortality from cold shocks;

          2.  Diricc or indirect mortality from excess heat;

          3.  Reduced reproductive success or growth as a
              result of plane discharge*;

          4.  Exclusion from unaccsptably larje areas; or

          5.  Blockage of migration.   Low Potantisl lapsct Ares.

          A discharge may be determined to be in a. lov potential iapacc
area for fishes within the primary and far field study areas if che
folloving conditions are satisfied:

          1.  The occurrence of sport and commercial species of fish
              is marginal;

          2.  The discharge site is aot a spawning or nursery area;

          3.  The thermal plume (bounded by the 2°C isotherm) will
              not occupy a large portion of the zone of passage which
              would block, or hinder fish migration under the most
              conservative environmental conditions (based on 7-day,
              10-vear low flow or water level and TM»-<«H» vater

          4,  The plume configuration will aot cause fish to become
              vulnerable to cold shock or have an adverse impact on
              threatened or endangered species.

3.3.3 .3   Study Requirements for Areas Xot Classified as Lov Potential
          1.  Methodology and Frequency.  Appropriate sampling methods
              and gear will be used to provide a basis for identifying
              the Representative Important Species (HIS)  of fish and
              their respective life stages in various habitats and
              strata within the study area.  Methods of fish sampling
              such as trawling, gill netting, seining, horizontal and
              vertical ichthyoplankton tows, etc., are acceptable.
              However, sampling methods will vary from one type of
              water body to another; therefore, a rationale for the
              choice of gear must be developed for each sampling
              program.  Unless stringent requirements for specialized
              gear is apparent, the adoption of standardized gear is
              recommended to permit comparisons with other studies.  At

    no cime during the study should new gear or sampling
    methods b« introduced unless ic can be demonstrated
    that the comparative efficiencies of ch« old and a«v
    g«ar and aethods *ra similar.  A change in sampling
    procedure* can only b« implemented after written
    approval by the Regional. Administrator/Director.

    For find studies, experimental design should be
    appropriate to determine the general characteristics
    of all life stage* of fishes inhabiting the primary
    and far field study areas.  The data collected should
    allow for a comparison of the relative importance of
    these cwo areas vlth respect to species composition,
    numbers of each type* growth, and reproduction.

    Samples shall be taken at monthly intervals to provide
    data representing seasonal and life stage habits except
    during and immediately following periods of spawning
    when a more Intensive sampling effort should be

    la northern latitudes, the monthly sampling requirement
    is subject to weather conditions and ic may be- necessary
    to provide the described data requirements from the
    literature and relate such information to expected
    discharge areas in a defendable rationale.  Also,
    rationale* could be developed from combinations of
    field data and Literature sources.

    It should be recognized that distribution of the various
    life stages) of fish is dependent upon many factors
    including season, water movement, light intensity,
    density gradients, and food sources,  as an example,
    during the appropriate season, night sampling will
    yield a more accurate estimation of the ichthyoplankton
    population because of their migration pattern during
    the dlel cycle.

    In meet cases, sample replication and frequency must
    be determined for individual sites and be based on
    field studies to provide valid population estimates
    using appropriate statistical treatments.

2.  Information Requirements.  The studies conducted should
    provide the required information which will be used for
    purpose* described above.  Some of the fish information
    may be required separately for 316(b) studies.  The
    applicant should meet with the Regional Administrator
    to determine which of the following information require-
    ments should be developed to satisfy 316(a) requirements
    at the site:

Species L«vel:  For the RIS, ch« following information
aay be required:

A.  Reproduction.  A discussion on spawning habits and
    fecundity characteristics of the principal species.

B.  Life stage habitat utilization.  A discussion on
    habitat utilized at the various life stages and
    seasonal timing of presence in. Che habicac types.
    Migration activity, if applicable to the designated
    species, should be addressed.

C.  Condition factors.  Comparative condition information
    for the principal species occurring ia the priaary aad
    far field study areas.

D,  Disease and parasitism.  Occurrence of disease aad
    parasitism in the indigenous populations and species
    susceptibility vithin the framework of expected
    thermal regimes should be- discussed.

Z,  Age and growth.  Trends in age and growth normally
    expected, in the species should be discussed.

Community Level;

A.  RIS and their general abundance.  Spatial and
    temporal distribution information on the RIS in the
    primary and far field study areas will provide
    information on which species will be aost vulnerable
    to intaka and/or discharge effects.

B.  Relative abundance of various species.  This infor-
    mation can be calculated from the sampling data.
    The relative abundance of a species is the value
    determined by dividing total amber of all fishes
    collected Into the utsibar of that species caugnt.
    1C is often reported as percentage of the total catch.
    Relative abundance can fluctuate seasonally and
    diurnally; however, it should not be significantly
    different from year to year.  Significant shifts in
    relative abundance over a period of tiae are
    indicative of changes within the fish community.

C.  Principal association.  By appropriate data analyses
    it is possible to identify principal associations.
    The principal associations are- the groups of species
    which are represented in samples in a consistent
    manner.  Presence or absence of a species directly

                      or indirectly depends on che presence or absence
                      of other species in che sample.   Significant
                      impact on one species, therefore, can result in
                      change* in principal Association*.

                  D.  Map requirement.  The applicant  should provide asps
                      depicting portions of the receiving  water body used
                      by the indigenous fish communities for such  activities
                      as spawning,  nursery, feeding, aigration,  resting,
                      etc.  The applicant should discuss and show  on che
                      aap the- proportion of the total  area used chat will
                      be influenced by che cheraal discharge co ch* Z°C
3.3.6   Other 7«rtebrate Wildlife   Decision Criteria.

              The section of the demonstration dealing with other verte-
    brates will be judged successful if che applicant can show the site is
    one of low potential impact for other vertebrates.  For other sites,
    the- section of the demonstration dealing with other wildlife will be
    Judged successful if the applicant can demonstrate, that other wildlife
    cotnunlty components will noc suffer appreciable nan or will actually
    benefit from th* heated, discharge.  The ten "other vertebrate wild-
    life" includes wildlife which are vertebrates (i.e., ducks,  geese,
    manatees, etc.)  but not fish.   Low Potential Impact Areas for Other Vertebrate Wildlife.

              Hose sites in the United States will be considered ones of
    lav potential Impact for other vertebrate wildlife simply because the
    projected thermal pliae will oot lapact large or unique populations
    of wildlife.  The main exceptions will be sites in cold areas (such
    as North Central United States) which would be predicted to  attract
    ge«s« and ducks, and encourage- them to stay through the winter.  These
    would noc be considered Low potential impact areas unless they could
    demonstrate that che wildlife would be protected through a wildlife
    management plan or other method* from the potential sources  of hara
      icloned in the. next section.
              Other exceptions: to sites classified as low potential
    Impact would be those few sites  where the discharge night affect
    important (or threatened and endangered)  wildlife such as aanatees.

              For nose other sites,  brief site inspections and literature
    reviews would supply enough information to enable the applicant to
    write a brief rationale about why the aite could be considered one
    of low potential impact for other vertebrates.

                                    -33-   Study Requirements for Och«r Areas.

              The applicant should undertake whatever investigation
    and planning steps are necessary co be able co writ* * rationale
    explaining what factor* (or wildlife management plans) will ensure
    that other wildlife will noc suffer appreciable hara from:

              1.  Excess heat or cold shock;

              2.  Increased disease and parasitism;

              3-  Reduced grovth or reproductive success;

              4.  Exclusion from unique or Large habitat area*; or

              5.  Interference vith migratory pattern*•

              In the rationale, the applicant should discuss the relation
    of the effluent to the habits and habitats of any threatened or
    endangered specie* or organism* of commercial or recreational importance.
                  3-4   Sow to Select the Most Appropriate
                        Demonstration Type
        The baaic recommended step* for the applicant's use in choosing the
aost appropriate demonstration type are summarized in section 3.2.2, the
decision train narrative.

        After completing Che initial screening; procedures and making
a. preliminary assessment of the- amount of additional work needed in
each blotic category, the applicant select* the demonstration type ao»c
appropriate for the site.  If the site i* one of low potential impact for
all biotic categories, the applicant may choose, the relatively streamlined
low potential impact Type III demonstration outlined in section 3.6.  If
not, the applicant should propose study plans based on. the Type II
guidance in section 3.3 or the Type III guidance in section 3.7.

        It Is recommended that the Type II demonstration be used a* a
guide- for the. amount of detail required in aost 316(a) demonstration*.
The actual amount of detail required for as individual location will vary
from site to site, but section 3.3 should serve a* a useful starting
point for dlscu*slon* between the applicant and Regional Administrator/
Director on what study plan* are most appropriate for a particular sice.

        Applicants not eligible for a low potential impact Type III
demonstration and aot desiring to do a Type II demonstration nay elect co
do an alternate (Type III) demonstration.

        If the sit* is on* of lov potential Impact for ao*c biotic
categories but act all, studies l*s« d*tail*d than choc* recommended is
section 3.5 may b* appropriate.  For example, if the sit* is on* of lov
potential iapect for all biotic categories except shellfish, th* Regional
Administrator/Director mighc conclude that few additional field studies
(except for shellfish) would b* required and that th* only RIS chat
should b* selected should b* shellfish.  This demonstration would b*
less- detailed than other Type II demonstration* and could b* referred to
as a Type III demonstration.
                3.2   Type II Demonstrations (Representative
                      Important Species)
        Th* Type- II demonstration should b* designed in such a aannar to
fully develop the chree key biological components:  completion of the
Biotic Category Rationales (begun, during eerly screening procedures),
development of RIS rationales, and synthesis of all information into a
master rationale.  This section provides a discussion of the recommended
components of the demonstration, a proposed format, and a discussion of
why th* data requirements are necessary for making 316(a) decisions.

3.5.1   Development of Biotic Category Rationales

        During1 early screening procedures of literature surveys and pilot
field investigations th* applicant will develop some of the information
needed to develop th* Biotic Category Rationales.  If the decision is
made to do a Type II demonstration following these early screening
procedures, the applicant should review sections 3.3 and 3.8.1, this
section, and th* data available, to determine what additional field
studies, if any, will b* necessary to complete the Biotic Category
Rationales.  In some cas*s, relatively little additional work will be
necessary.  la cases where additional work is required, the applicant
should complete th* studies as suggested in section 3.3 and then write
th* summary Biotic Category Rationales.

        Each Biotic Category Rationale should provide a complete dis-
cussion as to why, in th* judgment of th* applicant, th* impacts are
sufficiently inconsequential that the protection and propagation of
th* balanced indigenous population of shellfish, fish, and wildlife in
and on th* body of water will b* assured.  In the rationale, the
applicant should address each decision criteria for th* biotic category
in question.  Th* discussion should include an evaluation of the impacts
of th* discharges into th* receiving water body.

        Th« conclusions drawn should be supported with «n analysis of
the data collected during the 316(a) studies and/or by ch« inclusion
of supportive reports, documents and citations to the scientific litera-
ture.  The conclusions should represent a logical extension of the
information available and be scientifically dependable.  Where citations
are used that are not readily available in scientific journals (i.e.,.
interim reports, various type* of agency documents, annual reports,
theses, etc.), the documents themselves should be provided.
        If the iapacc of the discharge is projected using a mathematical
aodel, the applicant should provide a complete documentation of the
aodel thac is used.  The documentation should include a discussion of
the merits and disadvantages of the aodel.  The applicant should also
provide sensitivity analyses of the model and a verification study.  In
addition, the statistical reliability of the model's predictions should
be included along with a justification of the nethods used in the
statistical evaluation.

3.5.2.   Development of Representative laportanc Species Rationale

        The RIS Rationale should summarize why the results of the
laboratory and literature studies specified in section 3.5.2.Z suggest
that the RIS will not suffer appreciable harm as a result of the heated

        The asetimptions in the concept of RIS are:

        1.  Ic is not possible to study in great detail every species
            ac a site; there is not enough tiae, aoney or expertise.

        2.  Since all species cannot be studied in detail, some
            smeller number will have to be chosen.

        3.  The species of concern are those casually related to
            power plane impacts.

        4.  Some species will be economically important in their own
            right, e.g., commercial and sports fishes or nuisance
            species, and thus "important."

        5.  Some species, termed "representative," will be particu-
            larly vulnerable or sensitive to power plant impacts or
            have sensitivities of most other species and, if
            protected, will reasonably assure protection of other
            species ae the site.

    6.  Wide-ranging species at che extremes of ch«ir ranges would
        generally aoc be considered acceptable aa "particularly
        vulnerable" or "sensitive" reprasencacive species but chey
        could be considered as "importanc."

    7.  Often, all organisms that might be considered "laporcanc"
        or "representative" cannot be studied in detail, and a
        fuller list (e.g., greater than 1 but less than IS) may
        hare to be selected as the "representative and important"

    3.  Often, but aoc always, the most useful list 'would include
        mostly sensitive fish, shellfish, or other species of
        direct use to man or for structure or functioning of :he

    9.  Officially listed "threatened or endangered species" are
        automatically "iaportanc."   Selection of the Representative Important Species and
          Par Field Study Area.

          As previously discussed in the decision train (section
3.2.2, Seep 11)» applicants first meet vlth che Regional Adminis-
trator/Director to discuss selection of che RIS and define che
far field study area.

          The amber of RIS selected for a particular sice may be
high (5-L5) if che plans for biotic category field studies are aoc
comprehensive, or lav (2-5) if plans for additional field studies
are extensive.

          Somm of che criteria for selection of RIS are found in
che definition of the cerm (see section 4.0, Definitions and
Concepts) .  Keeping in mind these criteria and che assumptions
given above, the Regional Administrator/Director selects RIS from
any combination of che following biocic categories:  fish, shellfish,
or habitat formers.

          L.  Species Selection Where Information is Adequate.
              Where information pertinent to species selection
              is adequate, the Regional Administrator/Director
              should promptly select RIS. The applicant may
              suggest species for his consideration and may, as
              a part of its demonstration, challenge any selection.
              Other considerations are as follows:

Applicable State tfater Quality Standards.  If the
State's approved water quality standards designate
particular species as requiring protection, these
species should be designated, but alone say not
be sufficient for purposes of a Type II demonstra-

Consultation with Director and with Secretaries of
Commerce and Interior.  In the cases of species
selection by the Regional Administrator, he oust
seek the advice and recommendation of the Director
as to which species should be selected.  The
Regional Administrator must consider any tiaely
advice and recommendations supplied by the Director
and should include such recommendations unless he
believes that substantial reasons exist for

The Secretary of Commerce (National Marine Fisheries
Service) and the Secretary of the Interior (Fish
and Wildlife Service), or their designees, and
other appropriate persons (e.g., university
biologists with relevant expertise) , should also
be consulted and their timely recommendations
should be considered.  The Director should also
consult with the agency exercising administration
of the wildlife resources of the State (see section
3.2.2, Decision Train, Step 12).

Threatened or Endangered Species.  Species selection
should specifically consider any present threatened
or endangered species, at whatever biotic category
or trophic level, except that ao information should
be requested that would require field sampling
prohibited by the Endangered Species Act, 16 O.S.C.
L331 et seq. (see section 3.2.2, Decision Train,
Step 12}.

Thermally Sensitive Species.  The aost thermally
sensitive species (and species group) in the local
area should be identified and their iaportance
should be given special consideration, since such
species (or species groups)  might be aost readily
eliminated from the community if effluent limita-
tions allowed existing water temperatures to be
altered.  Consideration of the aost sensitive
species will best involve a total aquatic
community viewpoint.

    Raduced tolerance co elevated temperature 3*7
    also b« predicted, for example in species which
    experience natural population reduccioa during
    che summer.  Species having the greacesc northern
    range and lease southward dlscribucion may also
    possess reduced thermal tolerance.
B.  Commercially or tteereationally Valuable Species.
    Selection of commercially or recreationally
    valuable species should be based on a considera-
    tion of the benefits of assuring their protection.

F.  Far-Field and Indirect Effects.  Consideration
    should include the entire water body segment.  For
    example, an upstream cold water source, should aot
    be warmed to an extenc that would adversely
    affect downstream biota.  The impact of additive
    or synergistlc effects of heat combined with
    other existing thermal or other pollutants in the
    receiving waters should also be considered.

G.  Species Necessary (e.g., in the Food Chain or
    Habitat Formers) for che Well-Being of Species
    Determined Above.  In addition to the above
    considerations, it is suggested that che
    Regional Administrator/Director ask himself the
    following questions before selecting the RIS:

    1)   Is the potential problem with this species
        credible (documented, a problem elsewhere,
        a good prediction)?

    2)   Is the problem likely to be significant?

    3)   Which species occur at the location?

    4)   Which species is likely to be closely
        involved with the source or damage?

    5)   Does the problem species rank as "important'"*

    6)   Does the list of problem species fall in che
        range 3—13 or 2-5 (see text above)?

                  7)  Are the identified problem species "repre-

                  3)  Should other species aot clearly a problem b«
                      included as representative or important?

          2.  Species Selection Where Information la Inadequate.
              Wher* the available information is aac adequate
              ca enable, eh* Regional Administrator/Director to
              select appropriate RIS, he nay request the applicant
              accepting co aalui a TTP* II d«aonstracioa co
              conduce such studies and furnish such cvidcnct as
              aay b* necessary to eoable such selection.  Where
              species selection is based on information supplied
              by the applicant, the appropriateness of the species
              as representative and imp ore ant is an aspecc of cne
              applicant's burden of proof.   Laboratory and Literature Studies.

          The laboratory and literature studies to be done for
each RIS should be restricted to those which are necessary to fill
out sisraary Tables A and B and to develop (on the basis of the.
data svsamaries in those, tables) the &IS Rationale.  Mot all of the
data listed in Tables A and B may be appropriate for * particular
site or taza.  If che applicant feels that some are inappropriate
and should b* deleted, it should be discussed vlth the. Regional
Administrator/ Director ac the saae cime other discussions about
the RIS are taking place.

                  Assumptions for Tables A and B

      1,  The tables are a*rely aids to organizing biological
          data believed to be useful and Important for aaklng
          decision* regarding theraal discharge effects.

      2.  The species cable should be workable for any important
          or representative species selected, whether ic is
          •elected as a species for protection or avoidance
          (e.g., nuisance species).

      3.  All theraal characteristics do not apply in a
          similar context to all taxonovlc groups (taxa),
          requiring sotui special definitions or omission of
          a characteristic for a particular caxon.

 4.  There will be aontheroal influences (e.g., chemicals,
     scouring), often occurring simultaneously vich
     thermal influences, chat art aoc included in chis
     cable buc which should be considered in cheir own.

 5.  There nay a°c b» differences between adults and
     Juveniles of *\l caxa, or there may be more than
     mo distinct sensitivity cac«gori«s.  Oistlncclj
     dlffartnt lif« stag* r«quir«a«nts should b* listed.
 6.  Data can b* collected by che applicant for chose
     thermal characteristics of che IIS chat have aoc jet
     been determined but for which standardized aethods are
     readily available.

 7.  For certain parameters chat are still in che research
     or development stage, as opposed co standardized
     cesclng (e.g., gaaetogenesis requirements or predatioo.
     on cheraall7 stressed oeroplankton), all available
     published data would be useful but it would aoc be
     accessary to develop new data for chis category.
 8.  If more r**n one set of data- are available for any
     category, the several sets should be presented
     (and referenced) and che- rationale presented co aid
     in selecting one set for decision-making at che
     site in question.

 9.  Dates for gametogenesis and spawning Imply appro-
     priate- seasonal tlaes which will vary from area.
     to area and year to year even without che influence
     of che power plant.  The important point is whether
     these events would be- seasonally precluded.

10.  In fishes, optimum temperatures for growth and
     some performance factors (e.g., maximum swimming
     spe«d, greatest metabolic scope, final temperature
     preferendua, etc.) have been shown to be coincident
     for enough fishes that this coincidence is acceptable
     as a generalization.  Exceptions could be important,
     however, and should be identified.

                                        SAMPLE TABLE TO SUMMARIZE DATA FOR EACH
                                        REPRESENTATIVE IMPORTANT SPECIES (RIS)
                                                    COMMON NAME
  That area or tine under average and worst caae conditions that will not perait the epecific biological  fttnction  to
  occur aatisfactorily.

                                         TABLE 3

1. High Temperature Survival

   Aquatic Adult

   Juvenile (Immature)
TLjg, 24 hours

TL5Q, 24 hours
2. Thermal Shock Tolerance
   (Heat and Cold)

   Aquatic Adult
   Juvenile (Inmature)

   Early Developmental Stages
   (incl. neroplankton)
thermal gradient including
 worst case    T

single shock eo sisolate
 plant shutdown
double shock (up and down)
 in traversing plune
3. Optimum Temperature for
   Performance and Growth

   Non-breeding Adult
length, weight changes;
productivity; DMA/SNA Ratioj

length, weight changes;
DNA/RMA Rati02
4. yy^i«iff» Teaperature
   Regiae Allowing Early
   Development Co«pletion
long-cer« temperature
 exposure throughout development
 to Juvenile3
5. Kormal Spawning Dates
   and Te«peraeures
aonths; range for spawning
6. Special Temperature
   Requirements for
   As available in the literature only.
   Indicated by final preferendua for fish.

   Only for species readily reared or held in the laboratory.

   Narrative for Table B — Thermal Effects Parameters Applicable to
         lc 0 nanisms Selected As Representative Imoortant Soaciea
        Thermal effects studies applicable to major tax* or broad biotic
categories are summarized in Table 8.  Applicable thermal affects data
should be obtained for each US selected.  Remarks on study and notaa of
application of the results to make 316(a) and (b) declsiona are indicated

1.  High temperature survival for juveniles and adults:

    Mathod;  Determine TL_Q (e.g., 43-hr. - ultimata incipient lethal
    temperature) for juveniles and non-breeding adults.  Acclimation
    temperature should approximate the highest temperature at which the
    fish can be held.  Expoae in1ms1  to elevated temperatures in an acute
    (instantaneous) manner.

    Application of Results;  The TL.. value can be uaed for estimation
    of the upper non-lethal limit for the life-history stage in queation
    (24-hr. TL_. minus 2 C).  The TL.. value also can be used to
    estimate tne upper temperature limit for appreciable growth (24-hr.-TL5Q
    mlnus optimum growth time).

2.  Thermal shock tolerance of selected life-history stages:

    a)  For juveniles and adults, simulate winter plant shutdown
        stress of plum* entrained fishes and motile macro-cmatacea.

    Method;  Expoae organism* to acute temperature drops equal to the
    range of expected discharge    t's, using maximum winter plume
    temperature aa the acclimation temperature. Indicate temperature teat
    regimes which produce equilibrium loss of 50Z of the sample within 4
    hours and mortality after 24 hours.

    Application of Results:  Identified winter plume vs. ambient
    temperature conditions which could result in thermal shock in
    the event of plane shutdown, and an ensuing high loas of
    organisms due to markedly increased susceptibility to predation.

    b)  For meroplankton, simulate temperature shock upon traversing
        a thermal plume.

    Method;  Expoae eggs, embryos, and larvae to acute temperature
    elevations, followed by an acute drop in temperature at a
    series of exposure times and temperature gradients reflecting

    pU»e resident times and temperatures.  Ace1.1aatlon temperature
    should equal natural seasonal ambient condition*.  Mariana test
    temperature should rang* up to the TLjQ level for adults.
    Indicate time-temperature regiae leading to daath of 50Z of
    the sample.

    Application of Resultst  Lathai tiae-temperatura stress regime
    minua 2 C can be used to estimate temperature Limits of aonsal
    pray aroidanca bahavior.  Incraaaad. taaparatura ra«ulta in highar
    pradation pr««aura.

3.  Estiaation of optimtai taorearatura for growth:

    a)  Fish and oacroinvartabratai — dataralna rata of grovth
        (langch or waighc incraaaa) whan naintainad at a sarias of
        alavatad tanparaturaa and at otharvlaa naar-opclatin
        anTlronaantal conditions, with food providad ad libitun.

    b)  Fish — determinations of final behavioral temperature
        preferendua will closely correspond to the temperature
        which is optimal for many physiological processes,
        including growth.

    c)  Hacrophytes — determine temperature producing; maximum
        net photosynthesis for at least a 24-hour period, using
        an appropriate pbotoperlod.

    application of Results;  Optional temperature for growth can be
    combined with ultimate incipient lethal temperature limit for
    acceptable growth (see #1 above).

4.  Minimus optimum and msTlaiai temperatures allowing completion of
    early development.  Note:  Studies to be conducted only for RIS
    which are capable of being readily reared in the laboratory.

    Method:  Maintain fertilized eggs under a series of elevated
    temperature regiaas to determine minimum, optimum and maximum
    conditions permitting greater than 801 survival to completion of
    development of juvenile (i.e., post-larval metamorphosis; In
    fish, eo the point of successful initiation of feeding).  Note
    that diurnally cyclic temperature regimes with a 3°C total range
    can be more adaptive for enhanced thermal tolerance than is a
    constant, non—cyclic temperature regime.

5.  Normal spawning dates and temperatures:

    Method;  Cite range of dates (by month) and threshold temperatures
    reported to initiate and Inhibit gametogenesis and spawning, as
    reported la the literature for areas cloaely related to the water
    body segment in question.

    Application of Results;  To provide background information to
    evaluate seasonally the relative Impact of thermal discharge on
    timing of reproductive activities.

6.  Special temperature requirement for reproduction:

    Method;  Information should be provided as available in previously
    published studies.  Examples of relevant "special requirements"

    a)   Minimum of 10 C muse be experienced before gametogenesis
        can be Initiated In two boreal barnacles; and

    b)   Winter chill required for successful development In yellow

3.5.3   Engineering and Hydrological Data for Type II Demonstration

        This section describes the engineering and hydrologic information
which should normally be included in 316(a) demonstrations.  It also
suggests formats for presentation of such information.  The Regional
Administrator/Director may request additional information or excuse the
applicant from preparation of portions of this information as the situation
warrants*  The engineering and hydrologic information to be submitted
should consist of all information reasonably necessary for the analysis.
Where information listed in this chapter is not relevent co the particular
case, it should be excused.

        The. engineering and hydrologic information and data supplied in
support of a 316(a) demonstration should be accompanied by adequate
deacriptlve material concerning its source.  Data from scientific litera-
ture, field work, laboratory experiments, analytical modeling, infrared
surveys and hydraulic modeling will all be acceptable, assuming adequate
scientific justification for their uae is presented.

        In addition to the results obtained from analytical hydraulic
models the applicant should present, under separate cover, the model
which was used.  The model should contain a rationale explaining why this
particular model was used and explanations of *?J modifications to the
original work.   Plant Operating Data.

              1.  Cooling water flow.  Complete Table C (indicate units)
                  and provide a descriptive flow diagram.

              2.  Submit a time-temperature profile graph indicating
                  temperature on the vertical and horizontal scale.  The
                  graph should Indicate status of water camperature from
                  ambient conditions through the cooling system, and
                  finally the discharge plume out to the loC isotherm.
                  Worse case, anticipated average conditions, and ideal
                  (e.g., minimum time/temperature impact) conditions
                  should be illustrated (preferably on the same graph)
                  consistent with representative plume* illustrated.

              3.  The amount of chlorine used daily, monthly and annually,
                  the frequency and duration of chlortnation and the
                  maximum total chlorine reaidual ac the point of discharge
                  obtained during any clorlnation cycle.  The chlorine
                  demand of the receiving water body.  For existing
                  plants, a time-concentration graph of total chlorine
                  residual at the point of discharge during a chlorlnatlon

          4.   A list of any other chemicals, additives or other
               discharges (with schematic diagrams) which discharge
               into the cooling water system including generic name,
               amount: (including frequency and duration of application
               and the <•*»•«•»•• concentration obtained prior to
               dilution), chemical composition and the reason for

          5.   A map of existing dissolved oxygen levels including
               vertical profiles in the plume and discharge vicinity
               in 0.3 mg/1 increments for both average and worst
               case conditions.  Where stratification or the presence
               of Biochemical Oxygen Demand (BOD) discharges will
               possibly lead to depression of oxygen levels as a
               result, of the thermal discharge, the extent of the
               effect should be estimated.

          6.   A map of other contaminants within the plume caused
               by other discharges and natural sources for both
               average and worst case conditions.

3.j»3.2   Hydrologic Information

          1.   flow:  Provide information called for below as
               applicable to the location of the intake and discharge.

               A.  Rivers:  flow—monthly means and minima (rolling
                   mean, 7-day, 10-year low flows) for each

               B.  Estuaries:  fresh water input, tidal flow volumes,
                   nee tidal flux—monthly means and «1n1ms for
                   each—circulation patterns from typical tidal

               C.  Reservoirs:  flow through time, release schedules—
                   monthly means ftH minima.
               0.  Ocean*:  tidal heights and information  on  flushing

          2.   Currents:  Provide th» information called for  below,
               as applicable to the site:
               A.  Rivers:  I"**"", •**»•«<•"•  1Qd aean  current  speed
                   giving dally, monthly or seasonal fluctuations
                   and variations across cross-sections as  appropriate
                   to describe hydro-dynamics of ths primary
                   study area.  Include speeds at mean  annual flow
                   to 7-day, 10-year low flow.

          B.  Estuaries:  tidal and seasonal changes in current
              speed and direction.  (Vertical profiles of current
              are needed where density currents occur.)

          C.  Large lakes and oceans:   offshore prevailing currents,
              near shore currents/eddies; local tidal and seasonal
              changes in current speed and direction.

     3.   Tabulate or illustrate monthly and seasonal gradients
          for both thermal and salinity induced stratification
          at representative locations  in the study area (consistent
          with the complexity of che study area conditions) .  If
          intake and discharge conditions are identical then so
          state and provide only one tabulation or illustration.

     4.   Tabulate or illustrate ambient cemperature of che receiving
          waters, giving monthly means and monthly extremes for che
          preceding 10 years as data availability permits.  If
          comparable site waters are used, indicate the basis and
          limits of comparablity.  In addition, for biologically
          critical periods, weekly means and extremes, frequency
          distributions and daily variation should be provided.
          Temperature data upon which these values are based should,
          if possible, be obtained at least once hourly.

     5.   Indicate intake and receiving waters depth contours at 1 aeter
          intervals and any changes which may occur due to sediment
          movements, construction, etc.  Indicate bottom cype.
          Provide other significant features (e.g., thermal bar) and
          characteristics needed to evaluate the hydrodynamics
          of the primary and far field study area.  Information
          on water body size, surface area, volume, mean depth and
          maximum depth.

3.5 .3.3   Meteorological Data

          If energy budget computations are included as part of che
316(a)  demonstration, provide the following daily average meteoro-
logical data for the plant site, giving both monthly means and
seasonal extremes.  Indicate units:

     L.   Wet bulb air temperature.

     2.   Dry bulb air temperature (verified to site conditions).

     3.   Wind speed and direction.

     4.   Long wave (atmospheric) radiation (may be calculated).

          5.   Short v*ve (solar) radiation (may be calculated).

          6.   Cloud cov«r.

          7.   Evapotranapiration (may be calculated).

3 .3.3.4   Outfall Configuration and Operation.

          Provide the following information on outfall configuration
and operation, indicating units:

          1.   Length of discharge pip* or canal

          2*   Area and dimensions of discharge port(s)

          3.   Number of discharge port(s)

          4.   Spacing (on cantars) of discharge ports

          5.   Depth (mean and extremes)

          6.   Angla of discharge as a function of:

               A.   horizontal axis

               3.   vertical axis

               C.   current directions   Plume Data Requirements.

          The applicant will furnish estimates baaed upon model
 predictions and/or field data at existing plants of the folloving
 plume data:

          1.   Utilizing the load information in Table C, wind rose
               data and tidal/current data, a plume roee or locus of
               plisMS shell be provided for each calendar aonth.
               The plisies snail be bounded by the 2 C above
               aBbient isotherm.  This shall be done for both surface
               isotherms and bottom isotherms whan contact with
               benthic areas is made.

          2.   Representative plumes of the maximum size and aost
               frequently occurring plumes shall be detailed shoving
               instantaneous isotherms at the 2°C intervals co
               within 1 C of ambient for conditions of variations
               in tide, wind and currant.

A.  Rivers:  Plumes for average and 7-day, 10-year
    low flow* should be provided.

B.  Lakes and Reservoirs:  Plumes for summer conditions,
    winter conditions and after spring and fall
    overturns should also be provided.  For flood
    control reservoirs, plumes for various water
    levels should be provided.

For isotherm plots required in number 2 above,
vertical temperature profiles along the plume centerline
              extending to the bottom of the water body at
              intervals to within 1°C of ambient.   Engineering and Hydrologieal Data.

          The information required in this section, for the aost
part, consists of parameters which are necessary input to analytical
or physical predictive hydraulic or energy budget model*.  More
information may be provided by the applicant for his particular
demonstration, but this example represents the degree of detail
which will be necessary in aost cases.

          The following corresponds directly with the respective
paragraphs in section 3.6:

          1.   Plant Operating Data.  Table C - The data required in
               Table C are necessary because they are required for
               predictive modeling.  These numerical data also allow
               the reviewer to observe water usage.

               Time-Temperature Profile - The predicted tlae-temperature
               profile should be included because it Illustrates
               what a typical non-motile particle would be subject
               to when entrapped and/or entrained in the cooling
               wmter system.  Certain biological effects could be
               estimated with this type of input but the reviewer is
               cautioned not to assume this to be totally representative
               of stresses encountered on entrapped and/or entrained
               organisms.  This path is an idealized streamline
               which, in all probability, would not occur due to
               turbulence of cooling water flow.

               Chlorine - Chlorine is a toxic element and if it is
               to be used by the discharger to control the growth of
               flora and fauna in the cooling water system, its
               usage should be projected.  In most power plants
               chlorine la injected to the cooling water system for

pariods ranging froa L5 ainucas to cvo hours p«r
applicacion.  Tha auabar of applications is sic*
specific but usually cocals lass Chan cvo hours cocal
par day.  Idaally, only axact aaouncs of chlorina ara
introducad so chac ic raaccs antiraly, laaviag oo
activa raaidual ac cha discharga.  la pracciea chij is
difficult to achiara, and soaa chlorina coapounda ara
dlschargad.  Cblorina raaccs vich disaolvad organic
aattar in tha cooling vacar to font various chlorinacad
organics which may ba harmful co cha balancad indiganoua
coaaunicy.  Ic is charafora nacasaary co projacc cha
uaaga of chlorina and cooaidar cha rasulcs of ics
incaraccion vicb cha charmal coaponaac of cha discharga.

Tharmal Infraction - Saccion 316(a) spacifias chac
cha charmal cotiponanc of cha discharga ausc ba avaluacad
"... caking into account cha incaraccion of such
charaal componancs vich ochar pollutants...".  Uhila
data on such synargiscic affaces ara lialcad, cartain
inforaacion will aaaisc cha Ragiooal Adainiacracor/
Oiraccor in aaaasaing pocancial haraful incaraccions.

Otfaar Chaaieals - Tha addition of haac may incraaaa
cha affact of ochar chamicals in cha wacar body.
Chaaical inforaacion is naadad co avaluaca poaaibla
affacca of this kind and co proparly intarprac biological
daca for charaal affacca alona.

Hydrological Inforaacion.  This ancira saccion daals
vich conditions of tha racaiving watar.  This inforaacion
should ba raquirad bacauaa ic is basic siting information,
•odaling inpuc data and nacaaaary for propar incarpracacion
of biological data.

Mataorological Data.  This inforaacion should ba
includad vhara anargy budgat coaputaclona ara aada as
part of cha 316(a) daaonscracion.  Ic is not incandad
that all dsauraatracions includa this data.  Whan in
doubt tha applicant should discuss chis vich cba
Sagional Adalnlstrator/Piractor.

Outfall Configuration and Oparacion.  Thasa aiaaarical
data daacribing tha gaoaacry and oriancaclon of cha
outfall ara aacaaaary input for all pradicciva pliaa

              5.  Plume Data Requirements.  This data is the result of
                  the modeling effort.  While the results may be presented
                  in many formats, these suggested plume configurations
                  yield a graphic portrayal of where the heat is going.
                  These maps are necessary for aaklag qualitative and
                  quantitative- assessaents of biological changes.

3.5.4   Synthesis of All Information Into "Master" Ecosystem Rationale

        The Master Rationales of the deaonstratlon should summarize the
key findings in a concise manner and should fora a convincing argument
that the balanced, indigenous community will be protected.  The rationale
should include a summary of an "overall picture" of the ecosystem as
projected by the six Biotlc Category Rationales, the resource zones
impacted, and a summary of why the information in the rationales, along
with the predictions in the RIS Rationale, the engineering and hydrologlcal
data, and other .key facts, suggest that the balanced indigenous community
will be protected.
3.5.5   Suggested Format for Type II Demonstration

                      CITTAHPLE) TABLE OF CONTENTS

     I.  Introduction (Brief)

    II.  Master Rationale for Demonstration (see Section 3.5.4  for

   III.  Representative Important Species Rationale  (Section 3.5.2)

    IV.  Biotic Category Rationales (Section 3.5.1)

         A.  Phytoplankton

             1.  Decision Criteria
             2*  Rationale

         B.  Zooplankton

             1.  Decision Criteria
             2.  Rationale

         C.  Habitat Formers

             1.  Decision Criteria
             2.  Rationale

                                             COOUNG WATRR CHARACTERISTICS
% Capacity
40Z & Less
2 Tim* at

Intake Velocity
. 1
Channel | „
Ent ranee j ;>rr
     D.  Shellfish/Macroinvertebrates

         1.  Decision Criteria
         2.  Rationale

     £.  Fish

         1.  Decision Criteria
         2.  Rationale

     F.  Other Vertebrate Wildlife

         1.  Decision Criteria
         2.  Rationale
 7.  Brief Suaaary of Engineering and Hydrologic*! Data and Why
     Che Data are Supportive of cbe Predictions in the Above

VI.  Demonstration Appendices

     A.  Infomation Supporting Master Rationale

     B.  Information Supporting Representative Important Species

     C.  Information Supporting Biotic Category Rationales

     D.  Engineering and Bydrological Information

         1.  Baseline Data (see Section 4.1}

         2.  Discussion of Relationship of the Physical Data
             to the Suemary Rationales and Choice of Models
             or Other Predictive Methods

     E.  Supportive Reports, Documents, and Rav Data Hot From
         the Open Scientific Literature

3.5.6   Discussion of Why che Required Data are Necessary for Making
        316(*) Determinations   Biological D«t>.

              1.  Phytoplankton.  The organism* of the phytoplankton
                  eessusicy are « principal food soure* far seat
                  zooplankton and for some fish species.  They may
                  also become important In relation to industrial
                  or recreational water use If blooms of carcaln
                  species occur, vfalch can have a variety of dais-
                  carl oua affaccs (e.g., clog filters and intake
                  pipes, impart castes and odors to water).

                  Many water bodies, such as the aajority of rivers
                  and streams, can be classified as "low potential
                  Impact areas" for puTCopiaaktoa, and relatival/
                  little information is necessary for a 316(a)
                  deaottstration.  n«verch«lu«., aore detailed data
                  may be necessary in some instances if phyto-
                  plankton is a substantial component of food
                  chains supporting the balanced indigenous popu-
                  lation or if the thermal discharge is likely to
                  cause a shift towards nuisance species.  Even
                  if fira prtdletions cannot be aade on Che basis
                  of the increased data, these data nay be
                  necessary as a base for comparison with post-
                  operational monitoring surveys to detect long-
                  term community shifts.

                  A.  Standing Crop Estimates.  Estimate* of
                      standing crop are useful in determining
                      the importance of phytoplankton in the
                      productivity of the impacted body of water.
                      Productivity i» a principal factor in
                      defining high and low impact areas.

                  B.  Species Composition and Abundance.  Taatonomic
                      information will characterize the phytoplankton
                      associated with the discharge area and will
                      provide baseline data for detecting any
                      shifts in species composition accompanying
                      thermal discharge.  A change in composition
                      is often an indication, that a nuisance
                      condition «ay occur and that the food web
                      of the system is being altered.

    C.  Delineation of Euehotic Zone.  The euphotic
        zone of a water column is the upper layer
        inco which sufficient light penetrates to
        permit photosynthesis.  The comparison of
        this zone to the configuration of the
        discharge plume will indicate how ouch the
        thermal discharge vlll affect the produc-
        tivity of the lapacted body of water.

2.  Zooolankton and Meroplankton.  The zooplankton-
    aeroplankton coamunlty is a key supportive
    component of the aquatic system.  It is a primary
    food source for larval fish and shellfish and also
    makes up a portion of the diets of some adult
    species.  Many important species of fish and wild-
    life have planktonic life stages (termed aero—
    plankton, to differentiate them from organisms
    which are pLanktonic throughout their entire life
    cycle).  If a heated discharge kills or prevents
    development of the meroplankton, fever adult fish and
    shellfish will be produced each year. Estuarine
    environments are especially critical because of their
    high productivity and utilization as spawning and
    nursery areas for species with meroplanktonic larvae.

    Specific types of data are essential for the
    following reasons:

    A.  Standing Crop Estimates.  Information on
        standing crop helps in defining the importance
        of zooplankton and meroplankton in relation to
        the productivity of the affected system.  Any
        significant change in standing crop becoming
        evident during post-operational aonltoring aay
        indicate an adverse impact resulting from the
        heated discharge.

    8.  Species Composition and Abundance.  These data
        will identify dominant taza in the system and
        provide baseline information for observing
        changes accompanying thermal discharge.  Any
        appreciative alteration in the composition and
        relative abundance of the zooplankton and mero-
        plankton constitutes an imbalance in the
        community and Indicates possible adverse impact.
        Species data and related thermal tolerance
        information are also useful in developing thermal
        limits for the effluent.

C.  Seasonal Variations.  This information is
    essential for assessing impact because different
    species, with different thermal tolerances,
    become dominant at varying times of the year.
    It will also show when the iaportant aaro-
    plankters are present in the discharge area.

D.  Dial and Tidal Distribution.  Sampling to show
    dial and tidal fluctuations in depth distribu-
    tion arc necessary because zooplankton and
    aaroplanktoQ organism daaonstrac* distinct
    vertical mov«a«ncs which isay b« a fuaccion of
    both light intensity and tidal stag*.  Th«
    organisms arc thus vulnerable to a discharge
    plume in varying degrees at different times
    of the day.

Habitat Formers.  The role of habitat formers in an
aquatic system remains unquestionably unique and
essential to the propagation and well-being of fish,
shellfish, and wildlife.  Furthermore, habitat
formers, particularly in the marine and estuarlne
environments, are a liaited resource, slov to re-
establish, and non-renewable in some cases.  These
organisms are subject to damage by a discharge
plume in a number of ways.  Sooted aquatic plants,
including kelp, may be damaged or destroyed by
excessive temperatures, velocities, turbidity, or
siltacion.  Organisms may be damaged or destroyed
by chlorine or other biocides contained in sinking
plumes that flow along the bottom in winter.
Thermal discharges may affect the natural balance
of the bacteria and algae populations, favoring
the bacteria.  This situation, in turn, could
reduce oxygen levels by increasing the amount of
decomposing materials and could adversely affect
habitat formers.

The proposed studies represent a mlnlaal data
base for the evaluation of the applicant's
eligibility for modification of thermal treataent
technology requirements.  The data are necessary
for the following reasons:

4.  Mapping.  Aerial mapping is required for a
    detailed depiction of the spatial distri-
    bution of habitat formers in relation to
    the projected and actual plume configuration.

B.  Species Composition.  Species composition
    information will identify the types of
    habitat formers associated with the discharge
    vicinity and provide a basis for determining
    thermal tolerance level* for selected specie*.
    Also, baseline information on diversity is
    essential to determine any compositional
    shifts in species with the addition of heat.
    Species replacements are often the first
    signs of an Impending nuisance condition
    that ultimately leads to costly control and
    eradication programs.

C.  Standing Crop Estimates.  Studies to deter-
    mine seasonal increases in standing crop
    biomass serve two purposes.  First, a
    measured increase in biomass (dry weight)
    of primary producers over the grovlng
    season represents a conservative estimate
    of net production, which in turn represents a
    general measure of the functional well-being
    of the habitat formers and hence reflects
    the potential well-being of the organisms
    dependent on them for their success.  Veri-
    fication of this relationship requires
    concomitant sampling of the habitat for
    the presence or absence of the principal
    associated species.  A secondary purpose
    for standing crop estimates is to identify
    any accelerated growth of macrophytes with
    increasing temperatures, which could lead
    to nuisance conditions.

D.  Identification of Threatened or Endangered
    Species or Dominant Species of Fish Depend-
    ent Dpott Habitat Formers.  This information
    is useful in assessing impact in the case
    of adverse effects from heated discharge.
    Potential indirect adverse impact might
    otherwise be overlooked.

Shei, \ fish/Macroinvertebrates «  Functionally the macro-
invertebrate fauna serves man in numerous ways.  They
are an important component of aquatic food webs and
many invertebrates are directly important to man as
a source of high-quality protein and as bait for
sport and commercial fishermen.  They modify and
condition aquatic substrates and also aid in the

breakdown and decomposition of detritus, thus
contributing to detrital food chains, detrital
transport, and nutrient cycling.  Estuarine
systems are particularly important because of
their high productivity and their role as nursery
areaa for benthic species.

A. thermal discharge may have a variety of effects
on macroinvertebrates.  Aquatic insects having
aa emergent stage may enter the atmosphere early
as a result of artificial heating of the water.
The adults may emerge into cold air and die
because of exposure, because food items are not
in phase, or because normal egg laying conditions
do not exist.  Larval forms of marine inverte-
brates may develop at such high metabolic rates
that the survival of individuals may be reduced
during settling or maturation.  Thermal discharges
may stress ecosystems and cause shifts in community
structure such that although the total biomass
may not change significantly, desirable species
may be replaced by less desirable species not
involved directly in the food chain.  The dis-
charge of heat may cause stratification, which
may diminish dissolved oxygen in the bottom
Layer and possibly eliminate benthic fauna.

Specific types of data are useful for the
following reasons:

A.  Standing Crop Estimates.  These estimates
    are useful in determining the Importance
    of macroiavertebrates to the productivity
    of the river or stream being Impacted by
    the discharge.  As previously discussed,
    the productivity of the affected portion
    of the system is a key factor in defining
    lav and high impact areas.

B.  Community Structure.  The total number of
    species and the relative abundance of
    individual species (both components of
    diversity)  in an aquatic system are a
    function of the physical, chemical, and
    biological characteristics of the system.
    Because diversity is sensitive to signif-
    icant changes in the characteristics of
    the system (such as introduced heat), it

        can be an indicator of environmental stress.
        Additionally, a reduction in th« diversity of
        a system frequently results in a diversion
        of production into non-useful forma.

    C.  Drift.  In floving waters, drift is an important
        survival mechanism for aany species of macro in-
        vertebrates.  Since it is a passive function,
        the drifting organisms are subject to lethal
        temperatures occurring in a thermal plume.
        Drift is a stepvise downstream phenomenon, and
        aany aquatic insects have a concomitant upstream
        movement of reproducing adults.  The plume may
        thus affect populations both upstream and
        downstream from the area where mortality
        actually occurs.

    D.  Mapping.  Mapping is necessary for a detailed
        representation of the distribution of substrates.
        This graphic information is important in the
        design of sampling studies, evaluating the
        suitability of the system for various benthic

5.  Fish.  The discharge of waste heat can affect fish
    populations in many ways.  The various data required
    are necessary in order to provide characterization
    of the indigenous fish community for the development
    of the R.IS concept, to identify habitat utilization
    by the various populations, and to provide baseline
    information for comparison with post-operational

    Specific data parameters are related to possible
    adverse impacts from thermal discharge:

    A.  Species Level.  Information on the spawning
        habits of individual species are necessary
        for assessing impact because spawning times
        may be shifted by thermal additions or
        habitats may be altered by scour or by
        changes in the habitat former community.
        Habitat use by any life stage may similarly
        be affected.  Migration is an important
        factor to consider because thermal discharges
        can block upstream migration routes of
        spawning adults and downstream movements
        of small fish.  Condition factors are

        useful in evaluation because heat additions
        may cause a lots of condicion in certain
        species, •specially in winter when their
        metabolic rate is still high but food supply
        is low.

        The incidence of disease and parasitism may
        increase with a rise in water temperature.
        Age and growth data are helpful in comparing
        affected and aoo-affacted areas, pre- and
        poet-operational conditions.

    3.  Community Level.  Data on species composition,
        relative abundance, and principal associations
        will define the dominant fish species at the
        site.  Any appreciable change in these parameters
        signals an imbalance in the community and may
        indicate an adverse Impact resulting from the
        thermal discharge.  Species information is also
        necessary for developing thermal limit* for
        the effluent.

    C.  Happing.  Maps are required in order to represent
        habitat areas (used for spawning» migration, etc.)
        la relation to the configuration of the discharge

6.  Other Vertebrate Wildlife.  Data will be required in
    relatively few cases for this biotic category.  In
    those cases where data is required, the type of data
    needed is decided by the applicant.  The data
    selected should be the least amount of data necessary
    to complete this section of the demonstration.

7.  Representative Important Species.  Making predictions
    about "what will happen" are difficult without detailed
    information on the environmental requirements of
    communities or at least many populations and species.
    is- mentioned in section 3.5.2, it is not economically
    feasible to study each species in great detail at each
    site.  Therefore a few species are selected for
    detailed laboratory and literature survey.  The data
    requirements of Tables A. and 8 (section are
    recommended as being helpful to those making 316(a)
    decisions for the following reaaons:

A.  They allow an estiaation of the size of the
    areas which will b« excluded for key biological
    function* and the duration of the czclusioa.

B.  Th*y provide the b**is for ac l«*Jt rough
    prediction* of high temperature lurvival, heat
    and cold shock., and effects on reproduction
    and growth.

            3.6   Type *H ^°v Potential Impact Determinations
        If th« Regional Administrator/Director determines, after early
screening studies, that the ait* is on* of lov potential impact for all
biotic categories, the applicant nay elect to do a "short fora" demon-
stration, the "Low Potential Impact Type III Demonstration."  The basic
concept is that those applicants which have sites and proposed facilities
which obviously pose little potential threat to the balanced indigenous
population should be required to do less extensive (and expensive;
aquatic studies than other (more poorly sited or otherwise having acre
potential for adverse impact)  applicants.

        Type III demonstrations in general are essentially any alterna-
tive demonstration type agreed upon by the applicant and the Regional
Administrator/Director.  The Low Potential Impact Type III demonstration
proposed here is simply a recommended "short fora" demonstration which
considers information from each biotic category.  This ensures that no
major biotic category is ignored altogether and thus ensures that both
the regulatory agencies and the applicant have examined and mad*
judgments for each biotic category, but discourages collection of
excess or unneeded data-

        After the preliminary screening studies and determinations that
all biotic categories are of low potential impact, the applicant
summarizes this Information (along with engineering and hydrological
data and any other pertinent information) in one master rationale and
submits the demonstration to the Regional Administrator/Director.

        The format of the submittal should be similar to that suggested
in section 3.5.S except that the RIS sections should be deleted.

             3.7   Other Type IZI Demonstrations (Biological,
                   Engineering, and Oth«r Data)

        Those applicants aoc qualifying for a Low Potential Impact demon-
stration and act desiring to do a Type II demonstration, may (with the
written concurrence of the Regional Administrator/Director) do a regular
Type III demonstration.  A. Typ« III demonstration provides for th«
submit tal of any infomacion which tba Regional Administrator/Director
believes may ba necessary or appropriate to facilitate evaluation of a
particular discharge.  This demonstration also provides for submittal of
any additional information which the applicant may wish to have considered.
Each Type III demonstration should consist of information and data
appropriate to the case.

        Detailed definition of a generally applicable Type III demon-
stration is not possible because of the range of potentially relevant
information; the developing sophistication of information collection
and evaluation techniques and knowledge, and the case-specific nature
of the demonstration.  Prior to undertaking any Type III demonstration,
the applicant should consult with and obtain the advice of che Regional
Adminiatrator/Director regarding a proposed specific plan of study and
demonstration.  Decision guidance may also be suggested.

        If the site is one of low potential impact for most biotic
categories and/or there are other factors (small size or volume of
water impacted, low percentage of cross section of receiving water
affected, etc.) suggesting low potential for aquatic impact, the demon-
stration may not Deed to be completed in much more detail than the Low
Potential Impact demonstration outlined in section 3.6.  For most other
sites, the demonstration should reflect a degree of detail and degree
of proof comparable to the Type II demonstration (section 3.3).  While
Type III information may be different in thrust and focus, proofs should
be generally as comprehensive as in Type II demonstrations and should
result in similar levels of assurance of biocic protection.

        Each item of information or data submitted as a part of a Type
III demonstration should be accompanied by rationales comparable to
thos* outlined in sections 3.5.1 and 3.5.4.  The format of the
demonstration should be similar to that outlined in section 3.5.5
except chat the US sections should be deleted.

                          3.8   Decision Criteria
3.3.1   Biotic Categories

        Decision criteria for each biocic category art given in section
3.3.  The Regional Administrator/Director will compare the rationales
(and other data) for «ach biotic category vlch the decision criteria in
section 3.3 and determine if ch« decision criteria have been set.

3.8.2   Representative Important Species

        The Regional Administrator/Director will find the Representative
Important Species Rationale and other RIS information co be unacceptable
if the information presented:

         1.  is too incomplete to allow a clear assessment; or

         2.  suggests (or does act provide a convincing argument
             to the contrary) that the balanced indigenous popu-
             lation may suffer appreciable harm because of:

             A.  high temperature survival factors;

             B.  heat or cold shock;

             C.  improper temperature for growth, development,
                 and reproduction; or

             D.  the exclusion of areas and volumes of water
                 from the above functions in critical combina-
                 tions, of time and space.

3.8.3   Resource Zones in Aquatic Systems

        The strategies for reproduction, growth, and survival of the
indigenous biota of freshwater, estuarine, and marine ecosystems are
keyed to spatial and temporal variations in the structure (physical and
chemical) of the environment.  This structural variation in the environ-
ment, as it relates to the biota and to uses by man, has led to the
concept of resource or "value zones" for use in evaluating or predicting
the level of damage to aquatic systems from human activities.  Since
such zones vary in location, size, season of utilization, and criticality
of function, their identification is also useful in planning purposes
such as the siting of nixing zones for heated discharges.  Application
of this concept involves the identification and napping of resource

zones and critical functions* so that airing zones can be sited  in
areas having minimum adverse impact on aquatic resources.  Basic precepts
necessary to application of the resource zoning concept include:

        1.  All discharges in the water body segment oust be

        2.  The acceptable area of damage is related to the
            resource value of the impacted area.

        3.  In cases where the effects of the discharged waste
            are transitory, the timing of sizing zone use is
            related to seasonal utilization of the impacted

        4.  The acceptable area of damage is related to the
            total amount of equivalent area available in the
            water body segment.

        5.  Areas supporting "critical functions" should be
            avoided (note item 3 above).

        6.  Acceptable damage is related to species generation
            time and/or fecundity.

        7.  For a given location, the smaller the damaged area
            the better.   Typical Resource Value Zones.

              The following annotated list includes resource value zones
    which should be considered in the designation of sizing zones for
    heated discharges:

              1.  Spawning Sites.  Reproduction is obviously a
                  critical function in the survival of a species.
                  Two factors of importance in designating airing
                  zonee are the often limited area of habitat
                  suitable for the spawning of a species and the
                  limited time during which spawning occurs.
* A zone having a "critical function" is one that provides a major  con-
  tribution to primary productivity or is one that is limited  in  extent
  and necessary for the propagation and survival of a species.

    If the availability of spawning sices for an impor-
    tant species is Halted in extent, then such areas
    can generally be avoided, and should aoc be designated
    for che disposal of wast* heac.  If ic is totally
    impossible to avoid such sices, then Che use for
    mixing should be timed co avoid the period of
    spawning.  Seasonal avoidance is only feasible if
    Che effects of che discharge are transitory.

2.  Pood-Producing Areas.  The productivity of aquatic
    systems is directly related to the inputs of
    organic matter fro* green plants.  The free-floacing,
    relatively iamocile microscopic plants (phytoplankton)
    are short-lived vith rapid turnover rates and thus
    may not be critical in terms of mixing zones for
    heated discharges.  The rooted vascular plants and
    macroalgae (macrophytes) which, with suitable
    substrate, grow from the shoreline to the depth of
    the photic zone (depth to which 1 percent of
    incident light penetrates) are relatively long-
    lived and perform a number of "critical functions"

    A.  The production and export of vast quantities
        of organic fuel in the form of detritus—
        some are aaong the most productive plant
        cocBunities known.

    B.  As a, result of an abundance of food and
        cover, they serve as nursery areas for the
        ismature stages of many finfish and shell-

    C.  The trapping and recycling of nutrients.

    0.  The stabilization and building of substrate.

    Included in the category of food-producing areas are
    che wetlands—the Interface between terrestrial and
    aquatic environments—vhich, in addition to the
    above enumerated functions, serve as freshwater
    recharge areas that meter freshwater inputs to lakes,
    rivers* and estuaries.

    Because of the many Important and critical functions
    performed, the wetlands and other areas of macrophyte
    production in aquatic systems should be avoided when
    planning and designating mixing zones for heated

          3.  Nurs«ry Areas.  These *r« areas having an abundance
              of food and cover for the growth and development
              of che early lift stages of many fiafiah and shellfish.
              sisee th« «srly lif« stages are the period* of mmslsvsB
              growth rates and maximum vulnerability co predation,
              the availability of suitable nursery areas may b« the
              Halting factor d«c«rminlng chc *btmd«nc* of a species.
              Thus, che soass of frsshvsesr, estuariae, and aariae
              ecocysteaa identified aa aursery areaa have high
              resource value asd should generally be avoided when
              designating nixing zones.

          4.  Migratory Pathways.  Included in this category are
              routes utilised for sovsaaat co and froa spawning
              grounds, feeding grounds, and nursery areas; thus,
              che life stage involved say be adult, «gg, larval, or
              juvenile.  In sooe cases, chese pathways are very
              circumscribed; and total blockage could result in
              extermination of a population in che wmcer body
              segment.  Since cbese pathways serve a "critical
              function," they have high resource value and should be
              avoided when planning che discharge of waste beat.
              In situations where che usage of pathways is seasonal
              and che effects of the discharge are transitory,
              deleterious effects may be avoided by proper timing
              of disposal.  In term* of power plants, this seasonal
              usage is important in evaluating che feasibility of
              seasonal mode operacion of cooling devices.

          A consideration of zones critical co endangered species,
usage by waterfowl and wildlife, and shellfish beds are additional
resource values that must be considered when selecting tilling zones
for heated discharges.   Methodology.

          ae discussed above, discharge sites should be selected
which "ill hare the least impact on important resource zones and
"critical functions."  The application of this concept to the
selection of mixing zones is a stepwise procedure involving:

       - A, definition of the water body segment.

       - Selection and listing of R.IS in the water body segment
         and an enumeration of their strategies for propagation
         and survival.

Preparation of a map of the water body segment shoving
zones of resource use, including areas supporting "critical

Assignment of a aiaerical value, per unit area* to each
resource use.

Superlapose predicted plumes on resource maps and select
sites having least adverse impact on resource values.

 1.  Water Body Segment.  In lakes and estuaries having
     discrete and easily definable physical boundaries,
     the designation of the water body segment will be
     a straightforward process.  In large water bodies
     such as the Great Lakes, open coastal sites, and
     aajor river systems having ao definable and reasonably
     sized physical boundaries, the selection of the water
     body segment may pose a difficult problem.  Where they
     have been defined, the water body segments determined
     by the State Continuing Planning Process under section
     303(e) of the Act will apply.

     The seasonal movements of important species of aquatic
     life must be considered when defining a water body
     segment.  The spawning sites, nursery sites, and adult
     habitat sites of aany freshwater and marine species
     (examples include salaonids, shrimps, crabs, spot,
     croaker, flounder, white bass, walleye, etc.) say
     be widely separated and include physically different
     water bodies.  Seemingly slight impacts In the different
     areas used by such species may result in effects
     which, if considered cumulatively, would be intolerable.
     To avoid the potentially disastrous consequences
     of piecemeal consideration of adverse impacts, the
     water body definition should be sufficient to consider
     potential impacts throughout the contiguous range of
     populations of Important species.

 2.  Representative Important Species.  In general, this
     should Include all species and communities of
     species that are critical to the functioning and the
     productivity of the aquatic system defined by the
     water body segment.  Specifically Included are
     species or communities which are:

     • Commercially and/or recreationally valuable.

     - Threatened or endangered.

                  - Primary producers— particularly those communities
                    supporting relatively long-lived, fixed-location
                    species that perform multiple services (fora tod
                    stabilize habitat, produce organic matter, provide

                  - Necessary (e.g., in the food chain)  for the well-
                    being of specie* determined in 1 and 2 above.
                    Included here are the scavengers and decomposers
                    critical to the breakdown and utilization of
                    organic matter.

              3.  Map Preparation.  Haps of the water body segment
                  should, as a mininurn, include depth contours, adjacent
                  wetlands, tributaries and, in estuarine situations,
                  the average salinity gradient and sadinity stratification
                  should be visually expressed in cross section.  Resource
                  zones and areaa performing "critical functions" should
                  be superiaposed on the same or on a similarly scaled
                  aap.  To avoid overlapping detail, it may sometimes be
                  desirable to prepare separate maps for selected

              4.  Assignment of Values.  Once the resource zone* and
                  zone* supporting "critical function*" have been
                  identified and mapped, then values per unit area
                  can be assigned.  If the effect* of the discharge
                  are transitory and the use of che resource zone is
                  seasonal, the values may change throughout the year.
                  If the zone supporting a "critical function" is
                  limited in extent and is a function which limits
                  the abundance and/or survival of a species, then
                  that zone should be given a value of infinity and
                  thu* excluded from mixing zone use.  Other zones may
                  be assigned value* according to their area and their
                  Importance in maintaining different species.

3.8.4   "Master" Rationale, Demonstration a* a Whole

        The Regional Administrator/Director will find the demonstration
successful if:

        1.  It 1* found to be acceptable in all of the consideration*
            outlined la step* 20-25 of the decision train (section

        2.  There is no convincing evidence that there will be damage
            co the balanced, indigenous community, or community com-
            ponents, resulting in such phenomena a* chose identified
            in the definition of appreciable harm.

3.  Receiving water temperatures outside any (State estab-
    lished) mixing zone will not be in excess of the upper
    temperature Units for survival, growth, and reproduction,
    as applicable, of any RIS occurring In the receiving water.

4.  The receiving waters are not of such quality that in
    the absence of the proposed thermal discharge excessive
    growths of nuisance organisms would taJca place.

5.  A zone of passage will not be impaired to the extent
    that it will not provide for the normal movement of
    populations of RIS, dominant species of fish, and
    economically (commercial or recreational)  species of
    fish, shellfish, and wildlife.

6.  There will be no adverse Impact on threatened or
    endangered species.

7.  There will be no destruction of unique or rare habitat
    without a detailed and convincing justification of why
    the destruction should not constitute a basis for denial.

8.  The applicant's rationales present convincing summaries
    explaining why the planned use of biocides such as
    chlorine will not result in appreciable ham to the
    balanced indigenous population.

               3.9   Non-Predictive Demonstration* (Type I,
                     Absence of Prior Appreciable Harm)
        411 of the demonstrations done for HRC under the Memorandum of
Understanding are prtdicciv*.  Therefore, ch« prtdicciv* »«ccioo» of
this docuMnc vmr» co«pl«c«d fine.  Th* EPA and och«r «g«nci*« B*J
d*cid« co oounc 4 »«p*r»c« effort co rcvis* chis *«ccion «c a. Lacar
d»c«.  In the Masfrla*, ao»c of th« r*quir«a*ncs of section 3.2
(D«cision Train), 3.3 (Early Screening Procedure*), i.5 
                       4.0   Definitions and  Concepts

         The  definitions  and  descriptions in  this  section pertain to  a
number of terms and  concepts which are pivotal to the development and
evaluation of 316(a)  studies.   These  are developed for a  general
case  to  aid  the Regional Administrator/Director  in  delineating  a  set
of  working  definitions and  concise endpoints  requisite to  a  satisfactory
demonstration for  a given discharge.

Adverse  Environmental  Impact

      Adverse aquatic  environmental impacts  occur whenever there will be
damage  as  a result of thermal discharges.   The  critical  question  is  the
magnitude  of any adverse impact.

      The magnitude of  an adverse  impact should be estimated both  in  terms
of  short term and long  term impact with reference to  the  following  factors:

      (1)  Absolute  damage  (# of fish  or percentage  of larvae
          thermally impacted  on a  monthly  or  yearly basis);

      (2)   Percentage  damage (%  of fish  or  larvae in existing
          populations which will  be thermally  impacted,

      (3)   Absolute  and percentage  damage to any  endangered species:

      (4)  Absolute  and  percentage  damage  to any critical aquatic

      (5)  Absolute  and percentage  damage to commercially valuable
           and/or sport  fisheries  yield;  or

      (6)  Whether the impact would endanger (jeopardize) the
          protection and  propagation  of a balanced  population  of
           shellfish and fish  in  and on the body of water to which
           the cooling  water is  discharged (long term impact).

Aquatic  Macroinvertabrates

        Aquatic macroinvertabrates are  those  invertabrates that are
large  enougn  to be retained  by  a U.S.  Standard  No. 30  sieve (0.595-mm
openings) and generally can be  seen by the  unaided  eye.


Area of Potential Damage

        The area of potential damage  for RIS is  defined as that  area
of the thermal plume enclosed by the  isotherm which  coincides with  the
appropriate (designated by  the  Regional  Administrator/Director) water
quality criteria for that particular RIS.   This  area  can be determined
from the  plume  rose data specified  in section 3.5.3.

Balanced.  Indigenous Community

        The term  "balanced,  indigenous  community" as  defined  here  is
consistent with the term "balanced,  indigenous population"  in  section
316(a) of the Federal Water  Pollution Control  Act  and  40 CFR section  122.9.
A balanced, indigenous community  consists of  desirable species  of fish,
shellfish,  and wildlife, including the  biota  at other  trophic  levels
which are necessary as a part of the  food chain  or otherwise ecologically
important to the maintenance of the community. In keeping with the
objective  of the Act, the community  should be  consistent with  the  restora-
tion  and  maintenance of  the  biological integrity of the water.   (See
section 101(a).)   However,  it may  also  include  species  not historically
native to  the area which:

        1.  Result from major modifications to  the water body
             (impoundments)  or to the  contiguous land  area
             (deforestation  attributable to urban   or  agricultural
            development)  which  cannot  reasonably   be  prevented,
            removed, or  altered.

        2.  Result  from management intent,  such  as  deliberate intro-
            duction in  connection with a  wildlife  management program.

        3.  Are  species or  communities whose value is primarily
            scientific   or  aesthetic.

For  purposes of  a 316(a) demonstration,  distribution  and  composition of
the indigenous population should  be  defined  in terms  of the  population
which would be  impacted by  the  thermal  discharge caused by the  alternative
effluent limitation proposed  under 316(a).  A determination of the
indigenous  population should  take  into  account all impacts  on  the  population
except the  thermal discharge,   then, the  discrete  impact of the thermal
discharge  on the indigenous population may be  estimated in the course of
a 316(a)  demonstration.   In order to  determine the  indigenous population
which will  be  subject  to a thermal  discharge under  an  alternative 316(a)
effluent  limitation, it  is necessary  to  account for all non-thermal impacts
on the population such as  industrial pollution, commercial  fishing,  and the
entrapment  and  entrainment  effects of  any withdrawal  of cooling water through
intake structures  under  the  alternative 316(a)  effluent  limitation.   The  above
considerations  will  then make it  possible  to  estimate  the  true  impact of
the thermal  discharge  on the population.

 Balanced. Indigenous Population (31?)

         Tor the purposes of 316(»)  demonstrations,  the term "balanced,
 indigenous population"  is synonymous with the ctrm  "balanced.  Indigenous
 community" as defined above.

         A community in general is any assemblage of populations living
 in a prescribed area or physical habitat;  it is an organized unit  to che
 extent  chat it  has  characteristics additional to its individual and
 population components, and  functions as  a  unit through  coupled  aetabollc
 Critical  Function  Zone

        A zone  that  provides  a  major contribution  to  primary productivity
 or  is  one that  is  limited  in  extent  and  necessary  for the  propagation and
 survival  of  a species.

        The  Director  of  the  State  NPDES permit  program  in  those  Statts
which have been  delegated  the  program  by  EPA.

Discharge Vicinity

        The  "discharge vicinity" is  that  area described by a  radius
that is 1.5  times the maximum  distance from  point  of  discharge  to
within 1°C of ambient.   The  area of  the discharge  vicinity is based
on a 30-501 variation in the predictive thermal plume modeling.

Dominant Species

        Dominant species are defined as any  species representing five
percent of the total  number  of organisms  in  the sample collected according
to recosBMnded sampling  procedures.

        An estuary is defined as a semi-enclosed coestal body of water
which has a free connection with the open sea; it is thus strongly
affected by tidal action, and within it sea water is mixed  (and usually
measurably diluted) with fresh water from land drainage.  It may be
difficult to precisely delineate the boundary of estuarlne  and river

habitata  in  the upper reaches of a  fresh water river discharging  into
marine waters.  The interface is generally a dynamic encicy varying
dally and seasonally in geographical  location.  In such cases, determina-
tion of habicac boundaries should be  established by mutual agreement on
a case-by-case basis.  Where boundary determination is not clearly
established, both estuary and riv«r habitat biological survey requirements
should be satisfied in a combined determination for environmental
effects and best available technology for minimizing adverse impact.

Par Field Effect

        A far field effect Is any perturbation of the aquatic ecosystem
outside of the primary study area that is attributable to, or could be
expected, from the thermal discharge  (taking into account the interaction
of the thermal component with other pollutants).
Far Field Study Area (7TSA)

        The far field study area is that portion of the receiving
water body, exclusive of the primary study area, in which impacts of
the thermal discharge and its interaction with other pollutants are
likely to occur.  The area shall include:

        1.  The zones where the habitats are comparable to
            those existing in the primary study area, and

        2.  The zones inhabited by populations of organisms
            that may encounter the thermal effluent during
            their life history.

The actual boundary of the far field study area should be agreed
upon by th« Regional Administrator/Director.
Habitat Forgers

        Habitat formers are any assemblage of plants and/or animals
characterized by a relatively sessile life stage with aggregated
distribution and functioning as:

        1.  A living and/or formerly living substrate for
            the attachment of epiblota;

        2.  Either a direct or indirect food source for the
            production of shellfish, fish, and wildlife;

         3.  A biological mechanism  for  the  stabilization and
            •edification of  sediments and concribucing  Co
            che  development  of  soil;

         4.  A nutrient  cycling  path or  trap; or

         5.  Specific  ticca for  spawning and providing nursery,
            feeding,  and cover  araaa for fish and shellfish.

        For this docuaant, tha  earn "ascroinvertebratea" may ba
considered synonynoua vich "aquatic aacroinvertebratea" as dafinad

        For tha purpoaas of this docuaant, aeroplankton ara dafinad AS
planktonic life scagas  (oftan aggs or  larvae) of fish or invertebrates.

        Migrants ara nonplanktonic organisaa chac ara not parmananc
raaidants of tha araa but paaa through tha discharga zona and watar
contiguous to it.  Bzavplaa includa tba upatraaa algration of spawning
saloon and subaaquanc dovnatraaa migration of tha juvanile forma, or
organiaac that inhabit an araa only at certain times for feeding or
reproduction purpoaas.
Suisaaca Species

        Any alcroblal, plane or aniaal speciea which indicates a hazard
co ecological balance or huvan health and welfare chat ia not naturally
a dominant featore of tha indigenoua coaannlty may be considered a
aulaaaca species.

        Htilaance speciea of phytoplankton include chose algae taza
which in high concentration ara known to produce toxic, foul caating,
or odorifaroua compound* to a degree that the quality of water is
Other Vertebrate tflldlifa

        The term "other vertebrate wildlife" includes wildlife which
are vertebrates (i.e., ducks, geeae, nanatees, etc.) but not fish.


        Plant microorganisms such as certain alga*, living uaaccached
in the water.

        Organism* of relatively small size, aostly nicroscoplc, chat
either have relatively snail powers of locomotion or drift in the
waters subject co the action of v*vea and currents.
Primary Study Area

        The primary study area, is the entire geographic area bounded
annually by the locus of the 2°C above aabient surface Isotherm*
(determined in section ae these isothenu are distributed
throughout an annual period.  The reference ambient temperature shall
be recorded at a location agreed upon by the Regional Administrator/
Principal Maerobenthie Species

        Principal macrobenthic species are those dominant macroin-
vertebrates and plants attached or resting on the bottom or living
In bottom sediments.  Examples include, but are not limited to,
crustaceans, aolluska, polychaetea, certain macroalgae, rooted
macrophytes, and coral.
Regional Administrator (Director)

        ThU term refers to the Regional Administrator of the U.S.
EPA except that In those States which have been delegated the NPDES
permit program, Che term refer* to the Director of the State NPDES
permit profram.
Representative. Important Species (RIS)

        Representative, important species are those species which
are:  representative, in term* of their biological requirements, of
a balanced, indigenous community of shellfish, fish, and wildlife
in the body of water into which the discharge is made.  Specifically
included are those species which are:

        1.  Commercially or recreationally valuable (i.e.,
            within the cop ten species landed—by dollar

        2.  Threatened or endangered;

        3.  Critical to Che structure and function of the
            ecological system (e.g., habitat formers);

        4.  Potentially capable of becoming localized
            nuisance species;

        5.  Necessary in the food chain for the well-being
            of species determined in 1-4; or

        6.  Representative of the thermal requirements of
            important species but which themselves may aot
            be Important,


        All moHusk* and crustaceans (such as oysters, clams, shrimp,
crayfish, and crabs) which, in the course of their life cycle, con-
stitute important components of the benthic, planktonic, or nektonlc
fauna in fresh and salt water.
Threatened or Endangered Species

        A threatened or endangered species is any plant or animal
that haa been determined by the Secretary of Commerce or the
Secretary of the Interior to be a threatened or endangered species
pursuant to the Endangered Species Act of 1973, as amended.
Water Body Set»»"t

        A water body segment is a portion of a basin the surface
water* of which hare common hydrologic characteristics (or flov
regulation patterns); common natural physical, chemical, and
biological proceeses, and which have common reactions to external
(true, e.g., discharge of pollutants.  Where they hare been defined,
the water body segments determined by the State Continuing Planning
Process under section 303(e) of the Federal Water Pollution Control
Act apply.

        Animal microorganisms living unattached in water.  They
Include small Crustacea such as daphnia and cyclops, and single-
celled animals such as protozoa, etc.





       SECTION 316(b) P.L. 92-500
    U.S. Environmental Protection Agency
         Office of Water Enforcement
              Permits Division
          Industrial Permits Branch
              Washington, B.C.
                May 1, 7977

                            TABLE OF CONTENTS
   I.   Statement of Problem                                   1
  II.   Introduction                                           4
 III.   Information  Flow Chart                                 6
  IV.   Decision  Criteria                                      11
   V.   Definitions and  Concepts                               15
  VI.   Study Format                                           23
 VII.   Detailed  Study References                              25
VIII.   Site Description                                       26
       1.   Site  location  and layout
       2.   Meteorology
       3.   Additional  stresses on water body segment
       4.   Cooling  water intake structure
  IX.   Source Water Involvement                               29
       1.   Hydraulic  features
       2.   Probability  of entrainment
   X.   Biological Survey Requirements - NEW INTAKES           33
       1.   Sampling  design
       2.   Sampling methodology
       3.   Follow-up studies
  XI.   Monitoring Program - EXISTING INTAKES                 39
       1.   Sampling program --Entrapment-Impingement
       2.   Sampling  program ~  Entrainment
       3.   Follow-up studies
 XII.  Impact Assessment                                     45
       1.   Biostatistical  analyses
       2.   Predictive biological models
       3.   Community  response parameters
       4.   Biological value  concept

 XIII.  Acknowledgements                                       55
  XIV.  Literature Cited                                       56


                     LIST OF FIGURES

No.                        Figure

 1                    316(b) Flowchart
                     Existing  Intakes
316(b) Flowchart                  8
New Source Intakes

316(b) Flowchart                  9
New Intakes (Not New Source)

                       LIST OF TABLES
No.                        Table                       Page

 1                    Example Data Matrix               54
                     (Species I)  Data Sheet
                     (Spatial  Compartment [A])

     The Federal Water Pollution Control  Act Amendments of 1972
(Public  Law 92-500)  require  cooling  water intake structures to
reflect the best  technology available  for  minimizing  adverse
environmental  impact.

      Copling  water intakes can adversely  impact aquatic organisms
basically in two ways.   The  first  is  entrainment, which  is  the  taking
in of organisms  with the cooling water.   The  organisms  involved  are
generally  of  small  size, dependent  on  the  screen mesh size,  and
include  phyto-  and zooplankton, fish  eggs  and larvae,  shellfish
larvae, and many other forms  of aquatic  life.   As these entrained
organisms  pass  through  the  plant they are  subjected  to numerous
sources  of damage.  These  include  mechanical  damage  due  to physically
contacting  internal  surfaces of pumps, pipes  and condensers;  pressure
damage  due to passage through pumps; shear damage due to complex
water flows;  thermal damage due to elevated temperatures  in condenser
passage,  and toxicity damage  caused by the addition of biocides  to
prevent  condenser fouling and  other corrosives.   Those organisms
which survive  plant passage potentially could  experience  delayed
mortality  when  returned to the receiving  water.

      The  second way in which intakes  adversely impact aquatic  life
is through entrapment-impingement.   This is the blocking of larger
entrained  organisms that enter  the  cooling  water intake by some
type  of physical barrier.   Most electric  generating plants have
screening  equipment (usually  3/8"  mesh)  installed in  the  cooling
water flow to  protect downstream equipment such as pumps  and
condensers  from  damage or  clogging.   Larger organisms,  such as
fish which enter the system and cannot pas through  the  screens,
are trapped ahead  of them.  Eventually, if a  fish cannot  escape
or is not  removed,  it  will  tire  and become impinged on the screens.
If impingement  continues for a long time  period the fish  may
suffocate  because the  water current prevents  gill covers  from
opening.   If the fish is impinged  for  a short  period  and removed,
it may  survive;  however, it may  lose its  protective  slime and/or
scales through contact  with screen surfaces or from  the  high
pressure  water jets  designed to remove  debris  from the screens.
Delayed mortality to many  species  of  fish  following  impingement
may approach 100  percent.   For  some  species of fish, the intake
represents  a  double jeopardy situation where the same population
will be subject  to  increased mortality through  entrainment  of eggs
and larvae and  additional  mortality to juveniles and  adults through

     The  data  presently available on the magnitude of entrainment
losses  at  existing  electric generating  stations,  although  just  beginning
to accumulate,  reveals  very large  numbers  of fish passing  through  some
facilities.   Results  of one of these  studies, conducted at the Detroit
Edison  plant on  Lake  Erie near Monroe, Michigan, indicate that 400-800
million  fish  larv_ae  may  have passed  through that plant  during  April-
August  1974.       The fate of these  larvae has not yet  been determined
but the data from previous years  indicate that some  may  have  disinte-
grated during  passage  through the plant.

     Other studies have shown that mortality  ina^  be  high among fish
larvae that pass through plant  cooling systems   '    due mainly to
mechanical damage  or shearing forces.    '     The  circulating pump Jias
been identified as t^ most likely  site for mechanical  damage.
Coutant and  Kedl      in a simulation study have demonstrated that  the
condenser tubes  are  an unlikely site  for mechanical  damage  to  occur.

     A large  amount of  data  are  available  on the  magnitude of
entrapment-impingement  losses at  cooling water intakes.   The  data
available  on fish losses  at GrQeat lakes  cooling  water intakes  have
been summarized  by Edsall.       He  reported the  following losses:

          About 92,000  pounds of gizzard  shad at the
          Ontario Hydro Lambton plant on the St. Clair
          River in 6 weeks during December  1971  -
          January  1972;  82,187 pounds (nearly  1.1 million
           individuals)  at the  Detroit  Edison Company's
          plant on Lake  Erie near Monroe,  Michigan between
          April 1972 and march 1973, when the plant  was
          operating  at  less than maximum  capacity;  36,631
          pounds (584,687 fish) at the Consumers  Power
          Company's Palisades  plant on  Lake Michigan
          between July 1972 and  June  1973,  when the plant
          was operating at about 68 percent of  its  total
          capacity  (the  plant is now  closed cycle);  an
          estimated  1.2  million fish  (no weight  data given)
          at Commonwealth Edison's  Waukegan (Illinois)
          plant on Lake  Michigan  between June 1972 and
          June 1973; 150,000  pounds of fish at  the  Ontario
          Hydro  Pickering plant  on Lake Ontario in  April-
          June 1973;  659,000 fish (weight unavailable)  at
          the  Nine Mile Point  plant  generating  unit  number
          one  on Lake  Ontario during  intermittent sampling
          from January-December  1973, representing  an
          estimated total  of about 5  million fish at unit
          one  for that period; and about 67,950  pounds
           (929,000  fish)  at Commonwealth  Edison's Zion
          plant near Zion, Illinois, on Lake Michigan

          during September-December 1973 and March-June 1974,
          when the monthlv cooling water flow averaged only
          about * 5 percent of the maximum capacity.

     Approxina tely 1^,000 fish of i4 species were  impinged  in  1^'-
.it the Northern States Power Prairie Island Plant  on tin- Mississippi
3iver.    The Conmonwealth Fidison Company's Quad Cities pl.int,
also on the Mississippi River, impinged an estimated l.H -lilli^n
fish during 1974. 2

     The extent of fish losses of any given quantity needs  to  he
considered or a plant-by-plant basis, in that the  language  of  se<-ti
316(b) of P.I.. 92-500 requires cooling water intakes to ""ininize
adverse environmental impact."  Regulatory agencies should  cle.irlv
recognize that some level of intake damage can be  acceptable  if  t".i:
damage represents a minimization of environmental  impact.


     This  guidance  manual  describes the studies  needed to  evaluate the
impact  of Cooling water  intake  structures  on the aquatic  environment
and  allow for determination of  the best technology  available for
minimizing adverse  environmental impact.   The 1972  amendments to the
Federal Water Pollution Control  Act (P.I,.  92-500) require  in  section
316(b)  that:

           Any standard established  pursuant to section 301
           or  sect ion 306 of this Act and  applicable  to  a
           point  source shall require  that  the location,  design,
           construction and  capacity of  cooling water intake
           structures  reflect  the  best technology available
           for minimizing  adverse environmental  impact.

     Sections 301  and 306  of  the  Act refer to the development of effluent
limitations and  dates for  achievement of various standards  of performance
for existing  and new sources of waste  discharges.  The   steam-electric
generating point source  category is the largest  user  of  cooling water
in the  United States and this  guidance  manual  is directed primarily  at
this  category.   Other categories of point  source dischargers such as  iron
and  steel  and petrochemicals for which  intakes withdraw  a  major portion for
cooling water would  also require such  a determination.    This document is
intended for  use by  the U.S.  Environmental Protection Agency  (EPA),  State
water  pollution  control  agencies,   industry, and members of the public who
may wish to participate  in  such determinations.

     The  overall goal of conducting intake studies  should be  to  obtain
sufficient  information on  environmental  impact to aid in determining
whether the  technology selected  by the  company is the best available  to
minimize  adverse environmental impact.   In the  case  of  existing plants,
this  goal  will be  accomplished  by providing  reliable quantitative  estimates
of the  damage that is or may be  occurring and  projecting the long-range
effect  of  such damage to the  extent  reasonably possible.   In  the  case  of
proposed  intakes,  reliable estimates of  any future damage  are  to be
obtained  through the use of historical  data,  pre-operational  models,  and
the  operating experience of other  plants.

     General  guidance  is  provided  for the  development,  conduct, and  review
of surveys designed  to determine and evaluate that portion  of aquatic
biota potentially involved with  and subject to adverse environmental
impact  from  cooling water   intake  structures.  Guidance  is  also
supplied for  the analytical methodology  needed  to determine  the  extent
and  importance  of aquatic environmental impacts.  The   environment-intake
interactions  in  question are highly site specific and the  decision as
to best technology  available  for  intake design, location,  construction,
and  capacity  must  be made  on a case-by-case basis.

     Information  is not  provided on  available intake technology.  Such
information is contained in  the  "Development Document for Best Technology
Available for the Location,  Design,  Construction and Capacity of Cooling^
water Intake Structures, for Minimising Adverse  Environmental Impact,"
which  also  contains additional  references  on intake impacts,  miormation
is also  not  provided on non-aquatic  impacts of cooling water intake

     This document will be  most useful  in situations  where  siting  and
intake  design have  not been finalized; however,  procedures  to determine
and  evaluate the  environmental impact of existing cooling water  intakes
are included.

     Readers are  cautioned not to depend too heavily on this manual.
More specific  advice  as regards procedures and  individual   site  evaluations
will  be available  from  the agency staff  responsible for decision making
and  the  biologists who best  understand the area  in question.


     The development of 316(b) programs is a new procedure for many regu-
latory  agencies and  user  groups.   To  assist in an orderly processing of
data requirements for both  existing and  new cooling  water intakes,  flow
charts  have been  developed  (Figures  1,  2,  and  3).

     The process for evaluating  existing  intakes (Figure  1)  is  intended
to be flexible  so  that the  data requirements can be revised based on an
agency  determination of the potential  for  adverse  impact  and the availa-
bility of data on the plant's intake.    It is expected that for some
existing  plants,  sufficient  data may already  exist  to make  further  studies
unnecessary  for  a decision  regarding  best technology  available. The
process for new intakes  (Figures  2 and  3) is more  extensive  because of
requirements for  data acquisition  and models  prior  to site review and
approval  by the appropriate regulatory  agency.  Proper intake  siting,  in
many cases,  is the only way of minimizing adverse  environmental impact.
To  obtain the  necessary pre-siting  perspective, the utilization  of valid
historical data  and  local knowledge is essential.  A one- to three-year
biological survey is  required to  obtain,  in  a preliminary fashion,  the
necessary data for assessment of environmental  impact.   A one-year survey
is generally of  limited  value.  However,  in  circumstances  where  substan-
tial  valid historical  data  can  be  presented and the  intake can  be
represented as having  low  potential  impact, a  one-year survey may be
acceptable.   A decision  as  to the appropriate  number of years of pre-
operational data that  are  necessary will  be made by  the  agency  upon the
submission  of proposed  study  plans  and  their justification (see  flow
charts,  Figures 2 and 3).

     The type and  extent  of biological  data  appropriate in each case
will be  determined  by  the  actual or anticipated severity  or  adverse
environmental  impact.   Since  the  expected impact will vary,  it is  not
expected  that each  case  will require  the same level  of study.

     A decision will be made  at  the outset by the agency  as  to  whether
the  intake has high  or  low potential impact.   Low  potential  impact
intakes  are  generally those  in  which  the volume of water  withdrawn
comprises a  small percentage of the source water body segment and
are  located  in  biologically unproductive  areas,  or  that have historical
data shoving  no  effect,  or  which have  other considerations  indicating
reduced  impact.   High potential  impact intakes will generally require
extensive field surveys  or models to elucidate potential total  water
body effects.  New intakes will  provisionally be considered  high
impact  until  data is presented in support of an alternate finding.

                         Figure 1.
                                     316(b) FLOW CHART
                                     EXISTING INTAKES
Evaluated on basis
of existing data

Further field data unnecessary
                                  OR HIGH  IMPACT
                                   More  data
                                                     for  Best  Technology  Decision
                   HIGH IMPACT
                                               ; LOW  IMPA
'Submit  water
 body  plan  for
 agency  review
 and  recognition
 or alternate
                              Submit intake study
                              plan and justification
                              for agency review and
                              Intake data collection!
                             ;and status reports	'
Water body data
colleet ion
act ivicy
                               ^ Final Report
                               Best Technology
                                                           ^Further study
                                                       Continue operation
                                                       under NPDES permit
                                                       and follov-up studies


                          Figure 2.  316(b) FLOW CHART

                                     NEW SOURCE INTAKES
                     New Source Intake Prior to Construction
             'Submit pre-construction study plans and justification for
                            agency review and recognition	_____
        Decision made or appropriate number of years of pre-construction
        baseline data (1-3) and whether intake is high or low potential
                  -IHigh Impact|
                            Low Impact
study plan
or alternate
Pre-construction data collection
	and status reports	
             Begin construction
   ^[Pre-construction report
                            Agency renders preliminary Best
                            Technology Decision, approving
                               	site and plans
           >| Report pre-operation
               [Program modification
                                                Problem solution
                              Best Technology  approval,  begin
                              operation  under  NPDES  pennit  and
                              follow-up  studies  Including
                              verification  of  models used


                          Figure 3.  316(b) FLOW CHART

                                     NEW INTAKES (Not New Source)
                         New Intake Prior to Operation
                  Submit pre-operational study plans and Justification
                           for agency review and recognition
           Decision made on appropriate number of years of pre-construction
                  baseline data (1-3) and whether intake Is high or
                               low potential impact
                                                       Low Impact
model study
plan or
act ivitv
Pre-operation data collection
      and status reports
                                Pre-operation report
                            Agency renders Best Technology
                            Decision, approving site and plans
                              (including study plans)
              Best Technology
              Approval, begin
              operation under
              NPDES permit and
              follow-up studies
              verification of
              model used
                   Not Approved
                                  Minor change
                   Problem solution
                                                                        New  site
                                                                        or major
                                                                        change  in

     The inclusion of several points In the flow chart for .iy,rnry
and approval will ensure that all parties .ire In agreement -is to tin-
scope and specific details of work planned .md will provide each party
with a set nf specific goals and schedules for completion.  These review
points should also ensure that studies address the important environ-
mental and plant operational concerns of all parties, thereby resultinc
In timely and orderly completion.  A further benefit fron such review
Is that studies conducted throughout a water body segment can be
coordinated so that methods utilized will result in a comparable dat.i
base.  This uniform data base will allow for easier evaluation of any
subsequent cumulative effect from all Intakes operating on a water body.



     Adverse aquatic  environmental  impacts  occur whenever  there will be
entrainment or impingement damage  as a result  of the  operation of a
specific  cooling  water intake  structure.   The  critical question is the
magnitude  of any adverse  impact.   The  exact  point at which adverse  aquatic
impact occurs  at  any given plant  site or water  body segment  is highly
speculative and can  only  be estimated on a  case-by-case  basis by  considering
the  species  involved, magnitude  of the  losses,  years  of  intake operation
remaining,   ability to reduce losses, etc.   The best guidance  that can be
provided to  agencies  in this regard  would be to involve  professional
resource people  in the decision-making process  and  to  obtain  the  best
possible  quantitative  data  base  and  assessment  toojs for  evaluation  of such
impacts.    The Development document for 316(b)      is an essential reference
for guidance in these evaluations.

     Some general guidance  concerning  the  extent of adverse impacts can
be  obtained by  assessing  the  relative biological  value of  the  source
water body zone  of  influence for selected species and  determining the
potential  for damage by  the intake structure.   For  a given species,  the
value of an area is  based on the following  considerations:

           1.   principal  spawning  (breeding)  ground;

           2.   migratory pathways;

           3.   nursery  or  feeding areas;

           4.   numbers of individuals present; and

           5.   other  functions  critical  during  the life history.

     A once-through  system for a  power plant utilizes substantially  more
water from the source water  body than a closed recirculating  system  for
a  similar plant and thus  would tend  to have a higher  potential impact.
A biological value-potential  impact decision matrix for  best  intake
technology available could be:

1 (Relative to Source
High | No
Low | Questionable
• Water Body Segment)
Quest lonable
     (1)  An open  system large volume intake in an area of high biological
          value does  not represent  best technology available to minimize
          adverse environmental impact and will generally  result in

          Exceptions  to  this  may  be demonstrated  on a case-by-case  basis
          where, despite high biological  value and high cooling water
          flow, involvement of the biota is low  or  survival of those
          involved  is  high,  and subsequent reduction  of populations  is

     (2)  Generally,  the  combination of low value and  low flow most
          likely is  a  reflection of best  technology available  in  location,
          design,  and operation of the  intake  structure.  Exceptions to
          this could  involve significantly affected rare and endangered

     (3)  Other combinations of relative  value-impact  present  the  most
          difficult  problems.   In  such  circumstances,  the  biological
          survey  and  data analysis requires the greatest  care  and
          insight  in accomplishing  the  impact evaluation upon  which  the
          judgment  of best  technology available  is  based. A  case-by-
          case study  is required and local knowledge and informed
          judgment are  essential.

     It is  accepted that  closed cycle  cooling is not  necessarily the best
technology  available,  despite the  dramatic  reduction in races  of water
used.  The  appropriate technology is  best  determined  after a  careful
evaluation of the  specific  aspects  at  each site.  A  detailed  discussion
of available    intake technology  is contained  in the  316(b) Development
Document. 4'

     Biologicai survey requirements suggested in this manuai should
provide a sufficient daca base to provide insight as to the best
location, design, construction, and capacity characteristics appro-
priate for achieving minimai totai impact.

     A stepwise thought process   is recommended for cases where
adverse environmental impact from entrapment/impingement is occurring
and must be minimized by application of best technology available:

     The first step should be to consider whe trier trie .1 averse
     Impact will be minimized by the modification of trie ex.stint;
     screening systems.

     The second step should be to consider whether  the adverse
     impacc will be minimized by increasing the size of trie intake :>i
     decrease high approach velocities.

     The third step should be to consider whether to abandon the
     existing intake and to replace it with a new intake at a different
     location and to incorporate an appropriate design  in order  to
     minimize adverse environmental impact.

     Finally, if the above technologies would not minimize adverse
     environmental impact, consideration should be  given to :he
     reduction of Intake capacity which may necessitate  instal-
     lation of a closed cycle cooling system with appropriate JeSi^n
     modifications as necessary.

     Where environmental impact from entrainment must be minimized,
reliance must be placed primarily on flow reduction and  intake
relocation as remedial measures:

     Reducing cooling water flow is generally an effective means
     for minimizing potential entrainment impact.   In fact, this  may S<_-
     the only feasible means to reduce impact of entrainment where po-
     tentially involved organisms are in relatively  large concentration
     and uniformly distributed in the water column.  Entrapment  .ind
     impingement may also be lessened with  lower flow as proportionally-
     fewer animals will be subject to contact with  the  Intake structure;
     water velocities associated with the structure  can  be  reduced,
     enhancing probability of survival if  impinged  or of escape  if
     trapped.  Reduction of flow is accomplished primarily by an
     increase in condenser temperature rise or  through  recircuiating
     cooling systems.  When cooling water flow  is reduced, however,
     elevated temperature or the effects of an  auxiliary cooling system
     can increase the mortality rate of  the organisms that are entrained,

     Site location measures may prove effective in areas of
discontinuous, temporal or spatial occurrence (patchlness)
of those species subject to entrainment (or entrapment/
Impingement) .

     Enhancing survival of organisms once entrained In the  cooling
water system generally appears to be the least effective means for
avoiding adverse impact; however, operational regimes have  been
developed to decrease mortality of entrained species where  heat,
chlorine or both exert the predominant Impact.  Realistic laboratory
studies can Lead to optimal time-temperature regimes for survival.
The effects of biocldes can be reduced by Intermittent and  "split-
stream" chlorination procedures.  Mechanical methods for cleaning
cooling system components where feasible can eliminate or reduce
the need for biocides.  The mechanical stress of entrainment Is,  in
many cases, the critical factor in organism survival with the pump
the site of major damage.  At present, little can be done to
minimize mechanical impact although potentially harmful effects
may possibly be reduced by pump redesign which incorporates low
RPM, low pressure and wide clearance characteristics. Reducing
velocity changes, pressure, and turbulence in the piping system
should prove helpful.  Entrainment screening techniques such as
leaky dans may have application in some circumstances.  Regardless
of beneficial measures taken, many fragile forms will not survive

     In summary, the location of a power plant, or other cooling  water
use, coupled with the associated Intake structure design, construction,
and capacity results in a unique situation.  While generalities may be
useful, the optimal combination of measures effectively minimizing
adverse Impact on the biota is site and plant specific.  The best
technology available should be established on a case-by-case basis
making full use of the kinds of information suggested for acquisition
in this manual.



Adverse Environmental Impact

     Adverse  aquatic environmental impacts occur  whenever there will  he
entrainment or impingement  damage  as  a result of the operation  of a
specific  cooling  water intake  structure.   The  critical  question is the
magnitude  of  any adverse  impact.

     The magnitude of an adverse impact should be  estimated both in terms
of short term and long term  impact with reference  to  the  following factors:

     (1) Absolute  damage (#  of fish impinged or percentage  of
           larvae  entrained on  a monthly or  yearly  basis);

     (2) Percentage damage  (% of fish or  larvae in existing
           populations  which  will  be impinged  or entrained,

     (3) Absolute  and  percentage  damage to  any  endangered  species;

     (4) Absolute and  percentage  damage  to any critical  aquatic

     (5) Absolute  and  percentage  damage to commercially  valuable
           and/or sport fisheries  yield;  or

     (6) Whether the impact  would  endanger (jeopardize) the
           protectton and propagation of  a  balanced population of
           shellfish and  fish  in and on  the  body of water from which
           the cooling water  is  withdrawn (long term impact).
     This term refers to the Regional  Administrator  of the U.S.
Environmental Protection Agency  or the  Directors  of those  State
agencies authorized  to issue NPDES  permits.


     A community in general  is any aseemblage of populations living in a
prescribed  area  or physical habitat; it  is an organized unit to the extent
that it has characteristics  in  addition to its individual and population
components and functions  as  a unit through  interacting  metabolic  trans-
Critical Aquatic Organisms

     Adverse  environmental  impact  may  be felt by many species  in  all trophic
levels.   A species need not  be directly affected  but nevertheless harmed
due to loss of food organisms  or other associated  organisms  in  some  way
necessary for the  well-being  and continued  survival of the  population.
It is  not practicable  to study  all  species that may be directly or
indirectly  harmed by  Intake  structure operations.

     The  critical  aquatic  organisms concept  is defined in the  316(b)
Development Document.     Generally,  5  to  15  critical aquatic organisms
will be  selected  for  consideration  on  a  case-by-case  basis.   Relative
to  environmental  impact associated with  intake  structures,  effects
on  meroplankton  organisms,  macroinvertebrates, and juvenile and  adult
fishes  appear to  be the first  order  problem.  Accordingly,  the selections
of  species  should include a  relatively  large  proportion  of organisms  in
these  categories  that  are  directly  impacted.  Generally, because  of
short life  span and population regeneration  capacity, the  adverse  impact
on  phytoplankton  and  zooplankton species is less  severe.   It  is  suggested
that,  in  addition  to  study of the  selected  species,  the total  phytoplankton
and zooplankton  communities  be  assessed  to  determine  if the area  under
study  is  unique  and important  qualitatively  or quantitatively.   If
preliminary sampling  or prior data  does not  support  special or unique
value  of these  organisms  at  the  site,  phytoplankton and  zooplankton
species  will generally  not be selected.

     The following guidelines are presented for  selection  of critical
aquatic  organisms  for  consideration in intake studies:

     A.   Critical  aquatic organisms to be selected  are  those  species
          which would  be  involved  with the  intake structure  and are:

          1.  representative,  in terms  of their  biological
             requirements,  of a balanced, indigenous community
             of fish,  shellfish,  and wildlife;

          2.  commercially or recreationally valuable  (e.g.,
             among the top  ten  species landed ~  by dollar

          3.  threatened  or endangered;

          4.  critical to the   structure  and  function of  the
             ecological system  (e.g.,   habitat formers);

          5.  potentially capable  of  becoming localized
             nuisance   species;

          6.  necessary,  in the food chain,  for  the  well-being
             of  species  determined in  1-4;

          7.  one   of 1-6  and  have  high potential  susceptibility
             to  entrapment-impingement  and/or entrainment;  and

          8.  critical aquatic  organisms based on  1-7,  are
             suggested  by the applicant, and are  approved by
             the  appropriate regulatory agencies.

     8.  Assumptions in  the  selection of  critical  aquatic  organisms:

          1.   Since all  species which are  critical, representa-
              tive,  etc.,  cannot be stud  led in  detail, some
              smaller number  (e.g.,  5 to  15) may have to be

          2.   The species  of concern are those most likely to
              be  affected  by intake  structure,  design,  con-
              struction, and operation.

          3.   Some  species will be economically important in
              their own right,  e.g., commercial  and sports

          4.   Some  of the species selected will be  particularly
              vulnerable or  sensitive  to  intake  structure  impacts
              or  have sensitivities of most other  species and,
              if  protected, will reasonably assure  protection
              of  other  species at  the  site.

          5.   Often, but not always,  the most  useful list  would
              include  mostly  sensitive  fish,  shellfish,  or other
              species of direct use to  man,  or  to  the  structure or
              functioning  of the ecosystem.

          6.   Officially  listed "threatened  or  endangered
              species" are automatically considered "critical."

          7.   The species chosen may or may not be  the same as
              those  appropriate for a 316(a) determination
              dependent  on  the relative effects  of the thermal
              discharge  or the intake in question.

Cooling Water Intake Structure

     The coaling water  intake structure is  the total structure used  to
direct  water  into  the  components  of  the  cooling  systems wherein  the
cooling  function is designated to take place,  provided  that  the  intended
use of the major portion  of the  water so  directed  is to absorb waste
heat rejected  from the process or  processes  employed  or  from auxiliary
operations  the   premises,  including air  conditioning.

Ent rainaent

     The incorporation of organisms Into the cooling water flow is
entralnnent.  There are two generally recognized cypcs of cnt r.i Inment :
pumped entralnment -- referring to chose organisms that enter tlio int ikr
and are pumped through the condenser, and plume entra Inment -- rel'i-rr inr,
to organisms that are Incorporated into the discharge plume hy the
dilution water.  Plume entrainment is not covered by section 31Mb)  hut
Is part of the thermal discharge effect to be considered in conjunction
with thernal effects demonstrations under section 31Ma).

     The physical blocking of larger organisms by a harrier, gcncr.illy
some type of screen system in the cooling water Intake.  Entrapment
emphasizes the prevention of escape of organisms and Impingement
emphasizes the collision of an organism with a portion of the
struc cure .

     An estuary is defined as a semi-enclosed coastal body of water wliir'i
has a free connection with the open sea; it  is thus strongly aftertt>
     3.   a biological mechanism for the stabilization  and  modifi-
         cation of sediments and contributing  to  processes of
         soi 1  bui Idings;

     i.   a nutrient cycling path or trap;  or

     5.   specific  sites for spawning,  and  providing nurserv,
         feeding,  and cover areas for  fish and shellfish.
High Potential Impact Intakes

     High potential impact intakes are those located in biolr>gic.i 1 1 ••
productive areas or where the volume of water withdrawn comprises a
large proportion of the source water body segment or for which histor-
ical data or other considerations indicate a broad impact.

     See Entrapment-Impingement.


     Any naturally occurring large volume of standing water nccupvir-.e i
distinct basin and, for purposes of this document, reservoirs ind

Low Potential  Impact Intakes

     Low potential impact intakes are those located in biologically
unproductive areas and having low flow or having historical data showing
no effect or for which other considerations indicate low impact.  Plants
with low capacity factors or with few remaining years of lifetime might
be considered "low impact" despite their historical impact.


     For the purposes of this document, the term macroinvertebrates
may be considered synonymous with "aquatic macroinvertebrates" and
are those invertebrates that are large enough to be seen by the
unaided eye and can be retained by a U.S. Standard No. 30 sieve
(0-595 mm. mesh opening).


     For the purposes of this document,  moroplankton  are  defined  as
pianktontc life stages (often eggs or larvae)  of  fish or  Invertebrates.

     The ocean habitat, for the purposes of this manual,  is  considered
marine waters other than those water bodies classified  as  estuaries.   This
includes open coastal areas, embayments, fjords, and  other semi-enclosed
bodies of water open to the sea and not -neasurably diluted with  fresh
water from land drainage.

     Two principal zones within the oceanic habitat potentially  impacted
are:  (1) littoral zone — from high tide level to low  tide  level,  and
(2) meritic zone (near shore) — low tide level to the  edge  of  the
continental shelf.

     Phytoplankton are the free-floating plants, usually microscopic
algae, that photosynthetically fix inorganic carbon and are, therefore,
primary producers in some aquatic environments.

     Plankton are essentially microscopic organisms, plant or animal,
suspended In water which exhibit near neutral buoyancy.  Because of
their physical characteristics or size, most plankton organisms are
incapable of sustained nobility in directions against w.iter flow.  Con-
sequently, plankton drift more or less passively in prevailing currents.

     A population Is generally considered to be comprised of Individuals
of the sane species In a geographic ares.  Populations exhibit parameters
such *• Mortality, natality, fecundity, intrinsic rate of Increase,
density, etc.
Primary Study Area

     This includes the segment of the water body Jetemlned to be the area
of potential damage.  This concept is most pertinent t« organisms subject
to inner-plant passage, normally weakly motile or planktonic, and spatially

subject to water body currents ratr.er than possessing the ability t •
Change location independent of water mass movements.  Animals capable
large scale movements, i.e., migrant fishes, wili move into trus
per iodica1iy.
Rivers and Screams

     A river or stream is a nacuraliy occurring body of
waCer, wich an unbroken,  unidirectional flow, contained witnin .1  i. s
channel.  Reservoirs and/or impoundments, for che purposes
wili generally be viewed as lakes.
Secondary SCudy Area

     The area within the waCer body segment outside che primary study
area.  Biota in this area directly affected by the  intake structure m.r.
or may not be a significant component of the total  population of  indiee-1..^.;
species.  For many species, particularly pelagic  fishes, trie cota^ popula-
tion may be spread over a wide geographical area.   This area could be
considered the secondary study area.  However, other  intake structures
associated with cooling water uses, e.g., power  plants, may also  be
impacting the population in these other areas.   This  may be considered
in two wa y s:

     i.  consider the total population throughout  che geographical
         range, estimate existing Impacts, and determine to what
         extent the specific intake structure adversely impacts
         that portion of the population not already adversely
         stressed by sources outside  the primary  study area; or

     2.  consider only the population in the area  of  potential
         involvement and adjacent areas of occurrence not
         already Impacted by an existing source  of  stress.

     For example, when a number of  intake structures  are located  wic:-m
a water body such as Che Hudson River, Ohio River,  Long Island  Sound,
Western Basin of Lake Erie, Narragansett Bay, San  Francisco Bay,  etc.,
either of the two approaches may be taken to assess the impact  of  t'-.e
structure under consideration.  The totai Impact  of all existing  stresses
may be weighed against the total population of biota  studies and  the
adverse effects of the new stress added to existing stresses and  assessed
against impact to the total system.   The alternative  is to  assign a  se> .1 i •'•
of the water body not already impacted by other  intake structures and
compare the segment of the community  in the assigned  area  to the  effect
of the single structure concerned.

Threatencd or Endangered Species

     A threatened or endangered species Is any plant  or animal  chat  has
been determined by the Secretary of Commerce or the  Secretary  of  the
Interior to be a threatened or endangered species pursuant  to  the
Endangered Species Act of 1973, as amended.
Uater Body Segment

     A water body segment Is a portion of a basin,  the surface waters  of
which have common hydraulic characteristics (or flow regulation patterns)
common natural physical, chemical, and biological processes,  and which
have common reactions to external stress, e.g., discharge of  pollutants.
Where they have been defined, the water body segments determined by tiic
State Continuing Planning Process under section 303(e) of P.L. 92-500
Zone of Potential Involvement

     The zone of potential involvement Is considered the water mass
surrounding the Intake structure and likely to be drawn Into the structure
Itself or Into the associated cooling water system.  This varies with time
and Is dependent on ambient water movements In the affected body of source
water aa modified by the Influx of cooling water at the intake structure.
It will be difficult to precisely define the limits of this zone of
influence because of temporal and spatial variables.  The zone of potential
involvement always includes the primary study area and may include the
secondary study area.

     True zooplankton are free-floating animals which have little or no
ability for horizontal movement.  They are thus carried passively along
with natural currents in the water body.


     The  studies submitted  as  support for a finding that  the  cooling  water
intake represents best  technology available  for  a minimization  of adverse
environmental impact should be  in  the following format  to  facilitate
agency review.  At  least two  copies  should  be submitted.

      1.   Title page  (plant name, water  body,  company,  permit information.

     2.   Table  of  contents.

     3.   An executive  summary of 2-3 paragraphs (essence  of  material  and

     4.   Detailed presentation  of methods used  in  data collection,
         analysis and/or interpretation  when  different from standard

     5.   Supportive  reports, documents, and raw data.   Data from the
         open literature need  not be  included so long  as  it  is
         readily available.

     6.   Bilbiographic  citations  to page  number  of cited  text,

     7.   An  interpretive, comprehensive narrative summary of the
         studies  which  will  serve, in part,  as  the  basis  for  the
         agency's  decision.   The summary should include  a table
         of  contents and  may include table figures.  Sources of  data
         used in the summary should be cited  to  page number.    The
         summary  should  include a  clear  discussion stating why the
         report shows  (or  does  not  show) that the water  intake  structure
         in  question minimizes impact on the  water resources  and
         aquatic biota in the vicinity of the  intake and  throughout
         the water body segment.

     8.   An appendix  listing  the agencies and  consultants conducting
         this or related work  on the  water  body.

     9.   Reports generated  in  response to section 316(b)  should be
         recorded and  forwarded  to  the National Technical Information
         Service (NTIS)  for recording  and announcement.  The folder,
         NTIS-PR-184, available from NTIS, U.S. Department of Commerce,
         Springfield, Virginia 22161,  explains  the procedure  in detail.

     It is  the  intention of the EPA to  make the technical information
submitted  by industries in accordance  with  315(b)  available  for use
by other  industries,  scientists,  and members of the public.   This  will
be  done initially by placing  copies  in  the responsible  EPA Regional
Off Ice library.  A  similar approach is  also suggested for State  agencies.
In  cases where demand for the demonstration materials exceeds  the  capa-
bility of an  EPA or State agency library, the EPA Regional Administrator
may also  submit the materials  to  the NTIS  so that the reports  are
available co  the public in microfiche or hard copy form  at the price of
duplication.    In the meantime,  EPA is developing  lists of plants with
completed  316(b) demonstrations and will  submit  the plant  name  and an
abstract of each study  to  NTIS.

     It is  also  noted chat the  Atomic  Industrial  Forum has developed
INFORUM, a data  system  which will extract and index information from
reports  submitted by utilities in  accordance with  sections 316(a)  and
(b).  Questions should  be  referred to INFORUM  at  1747 Pennsylvania
Avenue, Washington, B.C.   20006, telephone 202-833-9234.


     This document, of necessity,  is  generalized to  provide  an  overall
framework of guidance and C9nceptual approach.   Six references are
recommended which treat  various aspects  of the  study requirements  in more
specific  detail:

          1.  U.S. Environmental  Protection Agency,  Office  of  Water
             & Hazardous Materials.  Water  Planning  Division,
             September 30,  1974, Draft,  316(a)  Technical Guidance
             on Thermal  Discharges. (Revised draft  to  be  published
             in  1976.)

          2.  U.S. Environmental  Protection Agency,  Office  of  Water
             6  Hazardous Materials,  Effluent  Guidelines Division,
             April  1976,  Development Document for Best Technology
             available for the Location,  Design, Construction  and
             Capacity  of  Cooling Water  Intake  Structures  for  Minimizing
             Adverse  Environmental Impact.

          3.  Battelle  Laboratories, Inc.,  Environmental Impact Monitoring
             of Nuclear Power Plants - Source Book.  Atomic   Industrial
             Forum, Inc.  August 1974.   810 p.

          4.  Aquatic  Ecological  Surveys.   American Nuclear Society,
             F.W.  Hinsdale,  Illinois, Draft, October  1974.

          5.  Entrainment:    Guide to steam  electric  power  plant cooling
             system siting,  design and  operation  for controlling damage
             to  aquatic organisms.   Amer.  Nuc. Std. Publ.  N18. -  1974.
             Draft, July  1,  1974, 44 p.  and appendices.

          6.  Entrapment/Impingement:   Guide to  steam  electric  power
             plant  cpoling  system siting, design  and  operation for
             controlling damage  to aquatic  organisms  at water intake
             structures.  Amer.  Nuc.  Std. Publ. N18 - 1974.   Draft,
             September, 1974, 24 p.  and appendix.


     The following information is generally needed  to  fully describe the
potential experiences of  organisms  which may be entrapped within intake
structures,  impinged on  parts  of the  structure and/or entrained in the
water mass taken in and  circulated through the associated cooling water
system.   It is necessary  to  describe the full range  of resultant  physical,
chemical, and  biological  parameters  of these experiences  which  could  be
encountered throughout  the  annual operation cycle.   Information on  daily
and  seasonal  fluctuations  is  of special importance  in  those waters
subject to wide variation in water  quality at the  specific site.  Other
data pertinent  to  the evaluation of environmental impact of the  location
or intake structure in question  should  be included even  though not
specifically  listed.

     The following data  are  required  for  adequate  description  of sites
located on  either fresh  or marine water bodies:

     1.   Site  location  and  layout

         A.  Location  of additional Intake  structures - Smaller scale,
             map  showing  locations of intake structures,  associated
             cooling water  systems,  and other pertinent discharges
             related to  surrounding  shore  and water  features in a
              50-mile  radius.

         8.   Site Plan  -  Larger scale map  with topographic and
             hydrographic data depicting  specific location of
              structure  in  the water  body.   Data  required  includes:

                     - Topographic  details

                     - Hydrological features (see  U.S. Department of
                        Commerce, National  Ocean Survey Charts, where
                        available),  including depth contours

                     - Water  body boundaries

                     - Affected  water body  segment

                     - Location and description  of  other cooling  water
                        intakes  in water body segment

                     - Existing  site  with topographic  and  hydrological
                        features as  changed  by proposed intake  structure
                        construction  and operation (where  applicable)

2.   Meteorology (when hydrodynamic modeling is performed)
              - Air temperature, maximum, minimum, mean-monthly
              _  Rainfall, monthly
              - Solar  radiation  kcal/m2/day  (average/month for
                 the annual cycle)
              - Wind speed  and direction,  prevailing  winds  identi-
                 fied as to seasonal patterns
              - Other relevant site  specific  data
3.   Additional  stresses on water body segment
              - Location of  existing  or planned  point sources  of
                 potential adverse  environmental  impact
              - Summary of impacts  associated with  existing or
                 future stresses  (and citations to more extensive
                 analyses,  such  as  316(a)  demonstrations,  impact
                 statements,  NPDES  permits, etc.)
4.   Cooling  water  intake structure
    A.  Structure
              - Location with  respect to cooling  water system
              - Location in  water body, horizontal and  vertical
                 (including skimmer  walls)
              - Configuration, including canals  and  channels;
                 detailed  drawings
              - Capacity
              -  Screening  devices (behavioral  and  physical)
              - Fish  by-pass and handling  facilities
              - Average and  maximum approach and thru-screen
                 water  velocities, by depth
              - Flow rates  and frequency  of occurrence  correlated
                 with  load characteristics
              -  Location,  amount, and  duration  of recirculation
                 water  for deicing or tempering
              - Other relevant system-specific data

     B.   Pumps

                 Design  details  (location  in structure, configuration
                 of  blades,  and  housing)

                 Revolutions per minute

                 Number,  capacities,  and planned operating schedule

                 Pressure regimes in  water  subjected  to pumping

                 Velocity shear  stresses  in pumping

                 Sites  of potential  turbulence  and physical  impacts

     C.   Biocides

                 Location of introduction  in system

                 Description and toxicity  of blocide  used

                 Timing and  duration  of  use

                 Concentrations  of biocide in  various parts  of
                 cooling water system and  receiving  waters

     D.   Thermal experience

                 Tabulation  of annual ambient  temperatures,
                 thermal addition to cooling water of various
                 operating capacities, and resultant  time-
                 temperature experience  of organisms  subjected
                 to entrainment  in cooling water  system

     F..   Other relevant data on  cooling  water  circulation  system

                 Dissolved gases

                 Suspended solids and turbidity

              -  Other wastes and chemicals added

                 Size of condenser tubes,  heat exchanger  com-
                 ponents, water piping,  siphon pits,  etc.

                 Maintenance procedures, use of heat treatment
                 or delcing procedures

5.  Plant Data

                 Age and expected lifetime

                 Capacity factor and percent of time at  fractional loads

                 History of  Intake model


     The physical interaction of the intake  and the adjacent water body
forms  a base for assessment of biological impact by  relating the behavior
and  motion of local  organisms  with the  flow of water around the site  and
into the  intake  structure.   To  determine this involvement  with  the  intake,
it is desirable  to identify the  type or types  of  circulation which will
be dominant in  the water body,  and to establish a program  of monitoring
currents and  other relevant hydrological and  physical  parameters of the
system.  Predictive  tools,  such as computer  models,  are  useful in
assessment  of impact,  and for  delineation of  the  area  of potential damage.
The  approach outlined  here  is  suggested for new plants having high poten-
tial  impact when  sufficient model  accuracy  is  obtainable.   The  approach
may be  useful  for other plants  as well,  as  discussed  in the impact  assess-
ment section below.  The modeling  program  should be discussed with the
agency in advance of application  and should include  sensitivity  analyses.

     1.  Hydraulic Features

         The dominant modes of circulation  in the  water body are
         frequently  identified  in the  literature  and include channel
         flow,  tidal and wind-driven currents,  estuary or  gravitational
         circulation,  littoral  drift,  and others.  The  local currents
          (or  velocity structure)  can be modified by bathymetry  and
         transient atmospheric  conditions,  and  contain local  features
         such as eddies;  their importance can he modified  by their
         effect  on biological  processes.   It is also useful to  identify
         interface zones  if  several current regimes or physical pro-
         cesses  are  evident.   Large water withdrawals  and  discharges
         can be  sufficient to modify existing hydraulic patterns  enough
         to  create new  biological  habitats.

         A program  of monitoring  the currents  and other relevant
         physical parameters  is  desirable for  the  study of  source
         water  involvement,  Whenever possible, historical  data  should
         be used to identify the expected circulations  and  guide  in
         the  selection  of instrument  stations,  although as  data  comes
         in,  a  re-evaluation of  the monitoring program is  useful.

         the  relevant parameters are  water current, speed  and direction,
         wind speed and direction,  tides  or local  water  levels,  tem-
         perature, and water density,  Salinity data  are important  in
         an estuarine  environment.

         The spatial distribution  of  instrument  stations is usually
         indicated by  the  circulation  regime  and local bathymetry,
         but  is  best organized to provide input to  and verification
         data suitable  for a predictive hydraulic model of the
         currents.   Vertical spacing  of instruments  should  be
         sufficient to  identify  any important depth  variation in
         the  circulation.

 The  use of a hydraulic model requires  several  other  specific
 inputs  to  provide realistic prediction of  currents  in the
 area,  typical  parameters  include:

       1.  boundary geometry;

      2.  bottom topography;

      3.  bottom  friction  coefficients;

      4.  latitude  of the  area;

      5.  tides  or water levels at open  boundaries;

      6.  river flows;

       7.  temperature and  salinity;

      8.  wind stress;

      9.  power plant cooling  water  flow races;  and

      10.  other point  source flow rates.

A significant period  of time (two weeks)  night  be chosen  for
a continuous (burst sampling)  monitoring  sequence to  sense
periodic variations in the  circulation, and  another program
to sample  changes on  an annual (or  longer)  cycle.  Careful
recording of placement  and start times is  recommended.

The  instruments  chosen  should be durable and  resistant to
fouling.  The  accuracy may be influenced by the scale of  the
parameters  but for water level should generally  be  at least
± 0.01  ft.  and,  for  current  speed and direction,  + .15 knots
and  ±  5.0°  respectively.   For  temperature  and  salinity
±  0.1°C  and   ±  0.1°/°°   respectively can be  expected.
Special  instrumentation for water current  sensing may be
necessary  at threshold  speeds.

An instrument calibration  program is necessary  to  insure
accuracy.   Redundant  marking of  station  locations and
provision for recovery of unmarked instruments  should be

Computer models  as  predictive tools  represent  the best
available predictive  tools  and are useful in assessing
water  use  and biological impact.   Mathematical models
solve the equations of water flow  and are used  to
predict currents  in the water  body.   Another model (of
water  quality) can  he  developed  in  tandem  to  solve  the
equation of mass flow and used co predict mass  or concen-
trations of organisms under influence of the  currents.

    The selection  of  the  appropriate  model  is  guided  by  the  circulation
    regime  and  the geonorphology  of  the  water  body.   A number  of
    mathenatical  models of  tidal  flow are  available,  and  these can  be
    extended  to include channel  flow.   For  example, the  Leendertse  8,
    9 type  square-grid  models  for tidal  currents  and  larvae  transport
    have been used.   Finite-element  models   are  being developed  for
    tidal circulation,  and  may  have  advantages in certain.areas.
    For river-bay  situations,  the channel-junction model   nay have
    special advantages.   Three-dimensional  models such as  those
    described in  references 12,13,  and 14  may  be  appropriate.   A
    conprehensive  summary of.available models  has been compiled
    by Cordon and  Spaulding.     The  rationale  for selection  of the
    particular  set of models  should  be justified  by either emphasizing
    their suitability or  by demonstrating  a lack  of other sufficient

    Verification  of model output  should be made for  both current
    and organism  concentrations.   Data from the monitoring survey
    are useful  for verifying  the  current model while  the biological
    sampling  program may  be used  to  verify the motion of organisms.
    Dye studies may also  be useful in model verification.

    Means for delineating study area and source water involvement may
    vary from intuitive judgments to highly sophisticated predictive
    models.  The  most logical measures, consistent with  the  local
    conditions  should be  determined.

2.   Probability of Entralnment

    The zone  of potential involvement of the cooling  water intake
    varies  with species of  organisms and time  but the core concept
    is the  determination  of probability of entrainment.   The
    predictive  models are useful  for mapping probability isopleths.
    This could  be done by the simulation of drifters  with the hydraulic
    model,  or the spread  of mass  from point sources  into the  intakes
    with the  concentration  model.  Drogue or dye  studies could be
    used for  verification.   Drifters, drogues, or dye may, however,
    be poor analogs for the organisms in question.  As a consequence,
    any study of  this nature must be accompanied  by justification
    that adequate adjustment  Is being made for differences in
    behavior  between the  organisms and their mechanical  analogs.

A map of probability of entrainnent  would  be  useful  in  delineating
the outline of the area of potential involvement  by  a  rational,
analytical method.  For example,  the computer hydraulic model  for
currents could be used to simulate the flow of drogues  in  the
region.  A simulated release of drogues (several  per hour)  woulj
be carried out until all drogues  have either  been entrnlned nr
have crossed the model boundaries and left the area.  The  ration
of entrained drogues to the total gives the probability of
entralnment.  A repetition of this procedure  for  other  release
points gives a field distribution of probability.

An alternate method is to simulate mass transport fron  a field >-{
points, wherein the ratio of mass entrained to the total released
gives the probability.  This method  could  be  verified  by the usu
of dye studies.

In environments likely to exhibit density stratification,  or in
which the organisms stratify, it  may be necessary to use multi-
level sampling for all parameters, and consider stratification in
the models chosen.  Wind effects are more  likely to  be  important
in shallow water.  The spatial changes In  parameters in stratified
systems are likely to be larger,  so this must also be incorporated
in a sampling program.

Obviously, models are highly desirable and the probability isopleth
concept Is a powerful analytical  tool.  However,  the time and costs
involved will not be Justifiable in many situations.


     The  purpose of the  biological survey is to provide  a sufficient  and
valid data base  for rational assessment of environmental  impact  related
to the  location,  design,  construction, and  capacity of a  cooling  water
intake  structure, prior to  a final siting  decision.

     Due to  the  possibility  of extreme fluctuations  in  overall  abundance
of the  species from  year to year  and shifts within a study  area  of its
centers  of abundance,  several years' study  may be  required.   A  term of
three years is suggested  as  permitting  an  "exceptional"  year to be
detected and  criticized on the  grounds  that events in so  short  a  span
cannot be understood in the  context of  long term trends.    A period of
 15 to 25  years is one in which many cyclic biological phenomena become
evident,  but a preliminary  study  of this length  will be  out of the
question except as it  can be gleaned from  historical data.   A  one-year
?re-operational study  is generally  of limited  value but  may be acceptable
  or  preliminary  agency  determinations  in  situations where  substantial
historical data can be  presented and  the  intake  can be  represented as
having  low potential impact.
     Data collected  must be  sufficient to permit  analysis and  reduction
to assessment  criteria which will be useful in reaching a judgment on the
existence  and extent  of an  adverse  impact.   Suggested measures  for  data
reduction and  analysis,  which  are  included in this manual,  should
be reviewed  prior to  development a survey program.

     Designation  of species of the  critical aquatic organisms to be
studied is the first  step  in a  sequence of operations for the
subsequent biological survey.  The  species  selected may or may not be
the same as the Representative Important  Species  designated  in connec-
tion with demonstrations  under section 316(a) of  the  Act.   Differences
would depend  on  the  grater or  lesser effect  on such  species of
thermal discharges or intakes.   Once species  and  source  water  involve-
ment  are  known, the sampling  methodology, survey study areas, and
temporal  characteristics of  the  survey can be determined to suit  the
organism selected, location,  and  characteristics  of the  intake
structure.   Each  survey should  be  designed on a case-by-case basis
recognizing the  uniqueness  of biota-site-structure  interrelationships.

     Biological  surveys  should be  designed and  implemented  to deter-
mine  the spatial  and temporal  variability  of  each of  the  important
components  of  the  biota that may be damaged  by the intake.   These
surveys  could  include studies of meroplankton, benthic  fish, pelagic
fish,  benthic macroinvertabrates,  phytoplankton,  zooplankton,  benthic
infauna and  boring and  fouling communities where appropriate.
Generally, the majority  of critical  aquatic organisms will  be  fish
or  macroinvertabrates.

     Once the occurrence and relative abundance of critical aquatic nr^i
at various life stages has been estimated, it is necessary tn determine
potential for actual involvenent with the intake structure.  An nr>;.inls:n
spend only a portion of its life in the pelagic phase and he susceptible
entrainment.  Migratory species may be In the vicinity of the intake for
short segment of the annual cycle.  Some species are subjected to  int.me
structure effects during life history stages.  For example, winter
larvae are found In the ichthyoplanlcton during their pelagic larval pl.j.^e,
and are susceptible to being entrained.  During later life stages, is
juveniles and adults, they are vulnerable to impingement.  Both ent re
                      used .

                   -  The number of sampling units  in each  sample.
                      The size  of  samples for  a specified  degree  of  prr-
                      clsion can often be calculated if  there  Is  son*
                      preliminary  sampling Information.   If  not,  preli-
                      minary sampling should be executed  before exten-
                      sive  programs are developed.

                      The location of sampling units in  the  s
    The survey effort  should be Intensive for  at  least  the  first
    year after which,  based  on first  year results  and  historical
    data, lower effort progams could  be  justified.   Survey  data
    are usually of a time-series  nature  and,  therefore,  averap.es
    over time intervals within the series cannot  be  assumed Inde-
    pendent.  This situation limits the  application  of  routine
    statistical procedures,  Bartlett     and Quenoville.
    Reference 19 is a  recent example  of  the difficulties encoun-
    tered when attempting to determine differences  in  portions  of
    a time-series.  The development of more powerful statistical
    methods for application  to this type of data  is  necessary.
    It appears that only catastrophic impacts  will  be  revealed  to
    temporal comparisons of  monitoring program data.  Plant
    Impact may be better revealed by  spatial  comparisons.

    The discriminating power of surveys  should be  estimated prior
    to implementation.

    This can be done by design based  on  previously  collected data
    at the site, or by assuming the variability of  the system based
    on previous studies at  similar sites.  The expected  discrimina-
    ting power of the  survey should be adequate for  the  purposes
    for which the data are  intended.

2.   Sampling Methodology

    Recommendations on specific sampling protocol  and  methodology
    are beyond the scope of  this  document.  The optimal  -nethodology
    is highly dependent on  the individual species  studied  coupled
    with site nnd structure  characteristics.   Some  general  guidelines
    are provided here.  More specific details are  provided  in
    reference 20.

                  Ichthyoplankton-Meroplankton Sampling

    Sampling gear used should have known performance characteristic.^
    under the conditions in  which it  Is  to be used,  or It  will  be  tested
    In comparison with a standard gear  (such  as the 60 cm.  "bongo" net
    developed for purposes  of Ichthyoplankton sampling by the
    National Marine Fisheries Service MARMAP  program).

    When a new gear is Introduced, data  should be  included  on its
    efficiency relative to  a standard gear.   Gear  should not be
    changed In the course of long-term  investigations  unless the
    comparative efficiencies of the old  gear  and the new can be
    satisfactorily demonstrated.

    It is recognized that no sampling Rear is, in  practice,
    strictly quantitative and equally efficient in retaining
    different sizes of organisms.

    A rationale for the choice of gear,  mesh  size,  etc., should be
    developed for each sampling program.  In  nost  cases, lackinp
    strong reasons to  the contrary, adoption  of a  standard  gear to
    permit comparisons with  other investigations is  reconmencicd.

In general, replicate tows Indicate that  horizontal  distribution
of fish eggs and larvae and other  planktonic  organisms  is  uneven
or patchy in character, and that  vertical distribution  not  only
of actively swimminp, forms but of  eggs  commonly shows  sonc
stratification.  This typically varies  over 24  hours due  to
the Influence of water movement and changes in  light Intensity.
Depth distribution of Individual  species  of fish eggs  -lay  char.f.e
during the course of development,  and buoyancy  may differ  at
different periods of the spawning season.

Night tows frequently produce larger catches  and may show  less
variability than day tows for fish larvae in  the sane  .irea.
Both phenomena are related in part to differences in net
avoidance under conditions of light and darkness.  However,
certain larvae may be altogether  unavailable  to the  usual
plankton sampling gear at some time of  a  diel cycle; for  example,
they may lie on or near the bottom by day, and  migrate upwards
at night.

Night sampling must be considered  in survey design as essential
for an accurate picture of the numbers of ichthyoplankton
actually present at a station, especially with regard to post-
larvae and young juveniles.  Sampling over the entire diel
cycle should be conducted.

Characterization of the ichthyoplankton  in a study area made
exclusively from single tows at a  series of stations is
Inadequate.  Replication sufficient to show the typical vari-
ation between tows will be necessary, and it must be borne in
mind that this may differ widely for different  species, and
may change over the course of a season.  In reasonably
homogeneous study areas, replicates can  be taken at  a subset
of stations and the results applied to the rest.  In certain
circumstances, close to shore, or  in the vicinity of the
proposed intake, more rigorous error analysis is advisable,
and this may require replication at each station.  Determina-
tion of a suitable number of replicates  will depend  on
characteristics at each site, and  must be based on  field
studies.  The most variable (patchy) of  the critical species
of ichthyoplankton under study at  a given season will
determine the number of replicates that  are desirable.

Confidence limits for estimates of abundance must be based
not only upon variation between tows at  a given station,
but must Incorporate other sources of error, which  Include
subsampling error (when aliquots of large samples are taken
for lab analysis) and counting errors.

Th e ichthyoplankton-meropiankton sampling will generally bt-
related to the impact of passing the organisms through the
intake structure and associated cooling water system, i.e.,
ent ralnment.

                    Fishes and Macroinvertebrates

Sampling of fish and macroinvertebrates will be generally
conducted in relation to the potential impact of entrapment
and impingement.  An exception would be juvenile and small
fish of a size that would pass through intake screening
rather than be caught upon such screens.

As previously noted, specific sampling methodology is detailed

Some specimens taken from the screens may appear healthy;
however, species-specific experiments with controls  to assess
the delayed mortality to these fish are required if  less  than
100 percent mortality is to be assumed.

Potential effects at proposed  intake structures  should make
maximum use of existing data at operating structures  to
extrapolate involvement and mortality estimates  to a  new
intake.  Attention  should be given  to experiments which have
statistically evaluated the effect  of  intake modifications
on impingement-entrapment losses.

In cases where preliminary surveys  Indicate  that the  entrap-
ment and entrapment-impingement losses may be high,  it will be
necessary to estimate the impact  of these  losses on  the
populations that will be involved.  For each  life stage
susceptible to entrainment and/or entrapment-impingement,
parameters necessary to adequately  predict  losses caused  by
power plant withdrawal  Include life stage duration,  fecundity,
growth and mortality rates, distribution, dispersal  patterns,
and Intake vulnerability.  These  parameters  can  be either
measured In the field or obtained from available literature.
Estimates of equivalent adult  stock loss on  the  basis of
entrainment losses  of immature forms  requires a  measure  of
natural mortality from  Immature to  adult.   For many  if  not
most critical species,  the natural  mortality may be  impossi-
ble to determine and the Impact may have to  be based on  a
reasonable Judgment.  Other data  are  required to project  the
long-term Impact of  the  Intake on the  population and to  include
the population size, its age structure, and  fecundity and mortal-
ity rates.  These data  can best be  synthesized using
mathematical models  as  discussed  in section  XII  of  this manual.


    Zoopiankton  sampling  will  generally  be  directed  Cowards
    determination  of  entralmnent  impact.   Zooplankton  are
    essentially  microscopic animals  suspended  in  water with
    near  neutral buoyancy.   Because  of  their  physical
    characteristics,  most are  incapable  of  sustained
    mobility in  directions  against water flow  and drift
    passively  In the  currents.

    In  most  cases,  intake effects  are  of relatively  short
    duration and confined to a  relatively small  portion of  the
    water body segment  because  of  short  life  span and  regenera
    tive  capacity.   Zooplankton,  however, should  not  be disr.
    from  consideration  without  a  preliminary  assessment of  the
    importance or  uniqueness of the  species'  assemblage at  the


    Phytopiankton  are free-floating  green plants, usually
    microscopic  in  size,  and are  generally the main  primary
    producers  in the  aquatic food web.   Again, the potential
    cooling  water  intake  structure impact on  phytoplankton
    would be through  entrainment.   The  short  life-cycle and
    high  reproductive capability  of  phytopiankters generally
    provides a high degree of  regenerative capacity.   In most
    cases, intake  structure effects  are of short  duration
    and confined to a relatively  small  portion of the  water
    body  segment.   Phytoplankton,  however,  should not  be
    dismissed  from consideration  without a preliminary assess-
    ment  of  uniqueness  or special importance  of  the  species'
    assemblage at  any particular  site.

3.   Foiiov-up  Studies

    Post-operational  studies at new intakes wili also be
    necessary in order  to determine  if the design, iocation,
    and operation,  in fact, minimize adverse  environmental
    impact and whether  the model  predictions  utiiized were
    realistic.  Some  suggestions  for follow-up studies are
    avaiiable  in section  XI.  However,  the appropriate program
    at  a  new plant  sice shouid be determined   in  large part   by
    the need for consistency with pre-operationai study results.


     The study requirements necessary  to  evaluate  losses of aquatic
life  at existing  cooling water  intakes  can be considered in two  separate
steps.   The first is  assessment  of the  magnitude of the problem at each
site  through direct determination  of the  diel  and  seasonal variation in
numbers,  sizes  and weights  of organisms involved with  operation of the
intake.  When losses appear to be serious,  as  a second step it may be
necessary to conduct studies  in the source water body  if there is  a need
to evaluate such  losses on  a water-body-wide  or local  population  basis.
However, before  requiring such  studies it  should be  realized  that the
natural variability of biological  systems,  the difficulty  of  separating
other  stresses  on  population size, and  difficulties in  obtaining  accurate
and precise  samples of the biota may mask the environmental impact from
C9olmg water  system operation.   The  magnitude of sampling variation ^
high and may range from 20 to  300 percent of  the probable  numbers.
Thus,  effects  of the Intake  structure often cannot  be  identified  above
this  "background  noise"  unless  they are considerably greater,   For
many  species,  adverse environmental  impact  may be occurring  at levels
below  that which  can be  "seen"  with the standard survey  and  analytical
techniques.  Such field studies therefore  will be  extensive  and  difficult
to conduct, and will generally  require several years of data  collection,
all without certainty  of results.   Such  studies should not  be required
unless absolutely  necessary for the best technology  available decision
and  then only to  address  specific  questions.   Because  of the  above
difficulties,   it may be  necessary to  base  a  determination  of  adverse
impact on  professional  judgment by experienced aquatic  scientists.

     In  evaluating data from  the following  studies,  it is  often  desirable
to assume "worst  case"  conditions  where all organisms which pass  through
the intake  suffer  100  percent  mortality.   If the  magnitude of the numbers
precludes such an analysis,  specific mortality estimates may  be  necessary.

     The following study requirements  are  based in part on the
recommendations  contained  in  the reports  of the  Lake Michigan Cooljng
Water  Studies Panel    and Lake Michigan Cooling Water Intake Committee:

1.   Entrapment-Impingement

    The  objective of this  sampling  program  is to document the
    magnitude  of losses  of fish life  at  operating  cooling  water
    intakes.   Since  it is possible  to obtain a  complete daily
    count of fish which  are  impinged  by collecting the intake
    screen backwash material,  this  intensity of collection
    should be  considered for  application through  one calendar
    year.   The  data which result  will most accurately  reflect
    the total  annual loss by  species.   This approach does ignore
    possible  delayed mortality to  organisms  involved  with the
    intake structure  but not impinged on the screens long  enough
    to be killed.   If  total entrapment-impingement mortality  is
    estimated by sampling  from the screens, the sampling  scheme
    must  consider  day-night  and  seasonal  differences.

    If a  less than   complete  dally count  over a year  is  utilized,
    dally  sampling  once  every four days for one  year  is  suggested
    as the lowest effort  which  will  be acceptable  from the  stand-
    point of allowing for reliable  loss  project tons  reflective of
    the plant's  operation.  Both more and  less intensive  sampling
    approaches may  also  be  justifiable based  on apparent  impact,
    intake data, spawning periods, and  other  site  specific and
    seasonal  considerations.   The  4-day interval for sampling is
    based on observed variability  in  daily  impingement losses.

    For example, in  a  study  of the Central Illinois  Light  Company's
    E.D.  Edwards Plant  on the Illinois  River,  numbers  of fish
    impinged varied  from 7,000 on July 18 to 500  on July 19.  On
    August 23,   1,500 fish were  impinged versus 30,000 fish on August
    26.    Not  all  plants exhibit  such wide variations  in  numbers
    of fish impinged;  however,  until intensive  sampling is completed
    at a  site,  total loss figures  will be  subject to question.

    Collection of the samples  can  usually be  accomplished by
    inserting  collection baskets in  the  screen  backwash  sluiceway.
    These  baskets should  have a mesh size  equal  to or  smaller than
    the intake  screen mesh.

    The  following  data should be  collected during the  sampling

    A.  Plant operating  data  required:

        1.  Flow rate;

        2.  Temperature   (Intake and  discharge);

                               _/, 1-
        3.   Tine started, duration, and anount of warm water ri-L:r._-:-
            lated for intake delcing and thermal defouiing;

        4,   Total residual chlorine contained in recirculated w.iter
            during condenser chlorlnation;

        3.   Current velocity at intake(s) over the range of w.acer
            volumes used in plant operation (representative neasurv-
            ments or calculated values may suffice);

        6.   Number of times screens are operated between sar,p i ;-.i:

        7.   Tidal stage (where appropriate) and flow;

        8.   Salinity (where appropriate); and

        9.   Dissolved oxygen if intake withdraws water  from an
            area (or strata) of potentially low oxygen  content;

    8.  Data required from biological collections:

        1.   Species, number, length, weight, and age group  (young  of
            the year, yearlings, or adults) collected from  the
            screens or representative subsamples when numbers of
            individual species collected are very large.   Subsamp „.:-..
            approaches should be approved  in advance by the Agency;

        2.   Representative samples of each species  for  determination
            of sex and breeding condition;

        3.   Numbers of naturally occurring dead fish  in the area
            ahead of the intake screening  system should be  estimated;

        4.   Periodically conduct a teat  to determine  the recovery
            rate of fish impinged on the screen.  This  can  be done
            by spiking the screen with  tagged dead  fish and deter-
            mining the proportion  that  are recovered  in the screen
            backwash sluiceway.

2.  Sampling Program - Entralnment

    The following section describes  investigations  necessary  to
    determine effects of entrainment of  phytopiankton,  zoopiankton,
    benthos, fish  , and shellfish at existing cooling water intakes.
    Such studies should generally concentrate on  fish and  shellfish
    unless  the phytopiankton, zoopiankton, or benthos are  uniquely
    important at the site in question.

                   Fish and Meroplankton

The potential for damage to fish or shellfish populations bv
entrainment depends on the number of organisms that pass through
the condenser system and on conditions experienced during passage.

Overall objectives of the study are to determine the species
and numbers of fish and shellfish eggs and larvae drawn intc
and discharged from the cooling systems and,  if necessary,
determine the Immediate and delayed effects of cooling system
passage on these organisms.

A pump system is acceptable as the primary sampling method,
provided it does not damage fragile organisms, and pumps are
easier to automate and quantify than systems  in which sampling
is done with nets suspended In the cooling water flow.

Diel sampling is recommended because the numbers of organisms,
even in areas known to be good spawning and nursery areas,
typically have low concentrations, and their distribution  in time
and space is usually either changing rapidly or patchy as a result
of natural conditions.  Therefore, adequate representation of these
organisms can usually only be obtained with continuous sampling
throughout a diel cycle.

The actual volume of water to be pumped to provide an adequate
sample is dependent on the densities of fish eggs and larvae  in
the water surrounding the cooling system intake structure.  The
sample volume should therefore be determined based on the  least
dense species of concern.  If no a priori  source water density
data exists, then as large a sample volume as can be handled will
be necessary.  Once information is developed on the  least
detectibie density for species of concern, sample volumes may be
adjusted accordingly.  This point  is extremely critical  to
acceptance of the resulting data.  If  the  sample volume  is  too
small the study will be biased and show fewer organisms  Involved
with the structure than actually exist.

Sample locations in the intake system  should be located  immediately
ahead of the Intake screens and, when  less than 100  percent mortality
!• aaauaed, at a suitable point in the discharge system.   When
less than 100 percent is assumed, samples  at  intake  and  discharge
should be from the same water mass.  At each  location one  sampling
point should be located near the surface,  one near  the  bottom,  and
one at mid-depth.  If uniform organism distribution  can  be  demonstra-
ted, one sampling depth may suffice.

Sampling should normally be conducted  continuously  at a  frequency
(e.g., every fourth day of plant operation) allowing  the  estimation
of annual numbers of organisms with a  95 percent confidence  interval
which Is + 501.  More frequent sampling may be  desirable  during

peak spawning seasons.   Sampling should 

    Znoplanktnn sampling will generally be directed towards detcr-
    ninati.'in of entralnment  inpact by an int.ike structure.  ^no-
    plankton .ire essentially .iiic roscop tc animals suspended  in w.-i t e r
    with ne.ir-ncMit ra 1 buoyancy.  Kccauso of tlielr physical  cii.ir ir-
    teristics, most arc Incapable of sustained mobility  in  J i rrc t ion-,
    against water flow and drift passively In the rurrciits.

    [n most cases, intake effects are of relatively short dur.it inn
    and confined to a relatively sm;i I 1 portion of the water body
    segment because of short life span and regenerative  capacity.
    Zooplankton, however, should not be dismissed fron cnns i icr.it L.TI
    without a preliminary assessment of the importance or uniqueness
    of the species' assemblage at the site.

3.   Follov-up Studies

    A follow-up monitoring program is also necessary at  existing
    plants to determine whether the approved  intake in fact
    minimizes environmental  impact.  In cases where an existing
    Intake has been approved, it would be expected  that  the monitor-
    ing program could be on  a reduced level fron that noted above.
    However, wliere significant changes in intake location,  design,
    construction, capacity,  or operation have taken place,  .1 program
    comparable to the pre-operational one should be followed.


     The  goal  of impact assessment is to analyze and reduce biological
survey data to a  form easily  conceptualized and  understood in the con-
text  of best  available technology  to minimize adverse environmental
impact of intake structure location,  design,  construction,  and capacity.
The  following  approaches  are  suggested  for use,  although their applica-
tion  will  not be  appropriate in each  case:

     1.  Biostatistical Analyses

         In  general,  the minimum reduced raw sample data should  include
         the arithmetic mean,  the standard  error  (or the  standard
         deviation),  and  the  sample  size from  which these  calculations
         were made.

         If a large  number of measurements or  counts of a variable
         (e.g.,  species)  are made,  the data may be  summarized as a
         frequency   distribution.   The form or  pattern of a  frequency
         distribution  is given by the distribution in  numerical
         form  (as in a  frequency  table).   However,  the data  is more
         clearly  evident  in a diagram such as  a histogram  (i.e.,  a
         graph in which the frequency in each  class is  represented
         by  a vertical  bar).   The shape  of a histogram describes  the
         underlying  sampling  distribution.   Known  mathematical fre-
         quency  distributions may be  used  as models for the populations
         sampled  in the  study,  and the frequency distributions  from
         samples may be  compared with expected frequencies from known

         The spatial distribution  of  individuals  in  a population
         can  be   described  in  quantitative terms.   In general, three
         basic types of  spatial distribution have been  described.
         They are:   a random distribution,  a  regular or  uniform
         distribution, and a  contiguous  or  aggregated  distribution.
         The  spatial dispersion  of a  population  may  be  determined
         by  the  relationship between the   variance and the  mean,  as
         well as  by  other  methods.   In a random distribution, the
         variance is  equal  to  the  mean.   The variance is  less than
         the mean  in a  uniform  distribution, and it is  greater than
         the mean  in a  contiguous distribution.  In general, a
         Ppisson  distribution is a suitable model for a  random
         distribution, a positive  binomial is  an  approximate
         model for  a uniform  distribution,  and  a negative binomial
         is probably the  most  often used, among  possible  models,  for
         a  contiguous  distribution.

         Temporal and spatial changes in  density can  be  compared
         statistically.   Significance tests  for  comparisons  of
         groups of  data may  be  parametric  when the distributions  of
         the parent  populations  are  known to  be  normal,  or  nearly
         normal,   from previous  experience or  by deduction from the
         samples.   Often,  non-normal  data may  be transformed into
         data suitable for  such  testing.   Otherwise,  non-parametric
         tests  for significance  should be  applied.

2.   Predictive  Biological Models

    Models used to simulate currents  (circulation  models) and  the
    dispersion  of constituents (concentration  models) are  becoming
    more  available for use  in  assessing impact.   These models,
    when   soundly-based conceptually, can  usually  be verified against
    hydrpgraphic  data  and,  therefore,  represent an  important tool  for
    considering the  influence  of a power  plant on its  surroundings.

    Diverse population and community models  can be developed,  but
    the assumptions on which they are based  are  difficult to test
    and the  parameters difficult  to estimate.   Some important
    parameters  depend  on  long  time series of data (tens  of years)
    and no level of effort  can  offset the requirement  of time.
    These  problems with biological models  can sometimes be overcome
    by making  "worse case"  assumptions  and  estimates,  but this
    course may tend to produce  a plethora of models  indicating
    potential  disaster.  Nevertheless, models  are a means of
    integrating the  available  information and  the subjective
    underlying  assumptions  about a problem in  order to produce
    the most rational  answer based on the inputs.   In this regard,
    some  models way serve an  important rule in assessing impact.

    As previously noted, hydrodynamic models in theory can he  used
    to predict  the source of water  drawn through a power plant
    intake  structure.   This is done by simulating  the movement of
    drifters or  the  dispersion of  a  constituent  originating  at  a
    particular point in the  area modeled.  The  simulation  is  carried
    nut for sufficient time  for  most of the  material to  be transported
    to the point of the assumed  intake structure  where it is con-
    sidered  entrained, or for the material to  be  transported  suffi-
    ciently far away  from  the  intake structure so that it has little
    chance of  future  entrainment.   This procedure  must be repeated
    (or performed  simultaneously) for  numerous constituent  origins
    and for  numerous initial  flow or tidal  conditions.   These
    results will provide  isopleths  of entrainment  probabilities
    surrounding  a  proposed intake  structure.   The  isopleths  can
    be compared with  the biological value zone to  assure  that the
    plant  will  not  draw a high  percentage of entrainable  organisms
    from  highly productive  areas.  Various intake locations  may be
    considered  to minimize  impact.  In  practice,  it might be very
    expensive  to  calculate  the  probability of  entrainment isopleths
    (source area) of an intake structure because a large  area may
    have to be modeled and considerable computer  time  expended.

Kor a given critical aquatic organism, It  may be possible to use
hydrodynamlc models to estimate the pero nt reduction in annual
recruitment resulting from entralnment ot  pelagic early life
stages.  When the source of pelagic eggs and/or larvae is known,
the dispersion of this biological material around the study area
and the consumption by a plant intake may be simulated, indicating
the reduction in recruitment that will result.  In this procedure,
entrainraent mortality is separated from natural mortality.  If
natural mortality Is density dependent, tne Impact of power plant
entrainment will be overestimated or underestimated when entrain-
ment mortality Is estimated separately from natural mortality.

The method described above for estimating the reduction in
recruitment resulting from entrainraent can only be applied, as
stated, for closed systems.  For the more common situation where
some larvae are dispersed out of the modeled study area (area
for which circulation and dispersion is simulated) additional
assumptions are required.  [f it is reasonable to assume that
once organisms have been transported out of the modeled study
area they have a low probability of contributing to support of
the adult population of the study area.  Then the dispersion
of organisms around the study area for a period of time equal
to the length of the species' vulnerable pelagic phase can be
simulated with and without the entralrunent impact of a simulated
power plant.  By comparing the number of organisms remaining
in the area, the reduction in recruitment to  iater stages of
the life cycle may be estimated.  This approach was used in
reference 24.  The approach ignores the possible  impact of a
reduction in the number of organisms dispersed outside the
modeled study area and other supporting populations.

For open systems where pelagic entrainabie organisms are dispersed
out of a modeled study area, it is often necessary to consider  the
effect of a plant on biological material transported across the
model boundaries and Into the system.  If sufficient Information
is available, Che concentration of organisms  .it the boundaries  may
be input to the model aa boundary conditions.  Again,  the situa-
tion with and without a plant Intake could be simulated and the
number or organisms remaining in the modeled  study area could  be
compared in order to derive an estimate of the reduction  in re-
cruitment.  The reduction in recruitment will change as the
population of the modeled study area  is reduced and becomes more
dependent on the input of biological material across the boundaries,

Hydrodynamlc models are of little value for predicting the
entrapment-impingement mortality rate suffered by populations.
In the case of separate but similar intakes,  this rate can be
estimated after one Is operational.   Results  may  then be
extrapolated to estimate the Impact of additional Intakes.
Predictive models for entrapment-impingement  .ire  under develop-
ment but have not yet been validated.

When the reduction  in recruitment  because  of  erera innrnt
and the Imp Inge-neat -mrtallty  rates  have  been  estim.ucu  lo
a critical  aquatic  oriidnisr,  it  is useful  en  .issess  Cut1
long-term Impact on tlic  local  population,   '.'tie dyn.r.iirs  ,i|"
the population can  be siniilated  by a  corap.irtmcnt  r-iortcl  witi
organisms distributed into cnnpartments according to ai;e.
Hach conpartnent is assumed  to suffer non-power ,r)l.nit  ro
mortality.  A^lng  is simulated by  advancing or^an l:>i,is  to  I'.i-
next older  compartment.  A^e-spccific fccunuity re  conpartnent s.  Coriputer
simulations of the  future  dynamics of t'ie  population bjsed i-i-
the conpartment nodcl witu and without  the plant  r.in be

Such simulations require knowledge of the  life tdblo tor  tlie
species being considered.  Life  cable information for some
species may be based on  the  literature.   It .nay be  possible
to supplement this  information with  knowledge  gained fron
field studies.  The age-(or  length-)  fecundity function
and the CRP, production-recruitment relationship nust also
be knovn.   The latter may  be  of  three forms:  (1)  recruitment
as a line.ir function of  egg  production,  (2) recruitment  as
a density dependent function  of  egg  production,  '     or  (3)
recruitment independent  of egg production.  The choice of  tin-
appropriate egg production-recruitment  relat lonsliip and
estimation  of parameters must  be  based  on  Che available
historical  information on  the  species.  At least  twenty years
of data Is  probably required  to  nake  such  a decision.  In  tiie
absence of  enough  data,  the  assumption  of  a linear  eg# pro-
duction-recruitment relationship  is  appropriate.   Note that for
a linear egg production-recruitment  model, there  is only a
single equilibrium  condition,  and  any plant related mortal-
ity la likely to disturb this  equilibrium.

If the population  Is not isolated, exchange with  other
populations may be  modeled.   The  results  of mark  and recapture
experiments may be  useful  for  estimating  exchange rates.

    Tho met hods  for  assessing impart  described  in  this  section
    are useful  but  of  unknown validity,   'lost  assessments  base;.
    on biological  models  have yet  to  be  field  verified.   Develop-
    ment of  predictive models for  assessing Impact  should  be
    encouraged  but  only after full consideration of the  diffi-
    culties  involved,  the expense-  compared  to  the  reliability of
    results, and die dangers of  .1  "worse  case"  analysis.

3 .   Community Response Parameters

    The populations  of all species in a  given  area  or volume
    are defined  as  n community.  Although the  term  "community"
    Is considered  a  useful concept in delineating  the group  of
    interacting  species in an area, it Is believed  to be  a
    subjective  entity.  Thus, for  specific  studies  .inc  tests
    of hypothesis,  the composition of tho community must  be
    strictly def tncd .

    Community response parameters, such  .is  chanp.es  in  structure,
    have sometimes  been studied  and estimated  by  certain rmilct-
    variate  classification techniques.  Various measures of
    species  diversity or  association  coefficients  have  also
    been employed  to measure community response to  perturbations

    In estimating  community diversity, the  most widely  used
    indices  .ire  those based on information  theory.   When the
    sample  of species' abundances  may be considered randomly t.ilv
    from an  ecological community or subconmunity,  the  Shannon
    index (also  referred  to as the Shannon-Wiener  or Shannon
    Weaver  Index)  may be  used.  If the sample  may  not  be
    considered  a randon set of species'  abundances  taken from ,1
    larger  species'  aggregation  of interest, then  the  Nrillouin
    Index should be  used.  Rlther  index  may be  computed  with
    computational  ease     and,  in either case, the logarithmic
    base used must  be stated.

    The shortcomings of all exist in;;  indices of species'  diver-
    sity and the biological phenomena which may influence
    these values should be recognized.  References  2H,  29, and
    30 should be consulted for further explanation  of  diver-
    sity indices and their utility.

    For the  purposes at hand, the  phrase "classification of
    communities" is  utilized for processes  that sort species
    Into groups, and it includes both discrimination and
    clustering.   In  general, discrimination techniques
    begin with  a priori conceptual distinctions or  with  data

divided Into a priori groups.   Then one should proceed to
develop rules which separate data into these a priori categories.
Clustering techniques, on the  other hand,  use a priori selection
of a measure of similarity,  a  criterion,  and a class description
to find Inherent empirical structure in data, i.e.,  clusters.
Clustering does not use an externally supplied label and involves
finding derived data groups  which are internally similar.  A
good review and summary of various discrimination and clustering
procedures is provided in reference 31.

The aquatic environment can  often be stratified in some way,
such as by depth, substrate  composition,  etc.  It is suggested
that such stratification be  done and that tables showing the
frequency, or density, of each species at each environmental
stratum be complied.  These  tables are analogous to the distri-
bution curves made in a gradient analysis, *" and are consi-
dered a natural and useful description for species association
data.  It is suggested that  these tables be the basis for
certain multivarlate methods of data analysis for spatial
and temporal variability, such as cononlcal variate analysis
described In reference 33.  In addition,  for these data which
now contain a priori groupings, the linear discriminant function
may also be successfully utilized for testing the differences
among environmental strata using multiple measurement or counting

Biological Value Concept

The concept of establishing relative biological value zones
In the water body segment Impacted by a cooling water Intake
structure could be a useful approach in determining best
technology available for intake design, location, and operation
to minimize adverse environmental Impact.  The principal use
of this concept  is In delineating the optimal location within
the water body for minimum Impact on the biota potentially
Involved with the specific intake structure.

The essence of this concept is in establishing biological value
of various zones for the water body segment  (or other defined
area) within which the intake structure is to be located.   A
judgment of value is made for the representative important
species considering type of Involvement with  the intake  (entrap-
ment, impingement, entrainment) and the numbers of each which
are adversely impacted.  Results are summed up by species,
seasonally or annually, and represented by graphical means  to
depict areas of the water body highly  important to the species
and, conversely, areas of low relative value, thus potentially
favorable intake structures.

Methodology.  The following -nethodo Ln^y  for using  the  biil--ic.il
value concept is based on :iet!mds develop «.•<•) and utilized  ;n
connnnity planning studies js described  in reference  3<« .

I'se of the biological value concept would require  acccp t jru:i_  i-t
the reasonableness of sever.il basic prenises:

1.  Then- are areas of Jlffercnt concent r at tons of  represent.11 LV<,-
    Important species within die water body segment conprisLnr.
    potential sites for an intake structure.

2.  -\reas of biological concent r.J t ions can be expressed  ;-i
    of relative value to perpetuation of representative  in
    species populations In the water body sop,.T>ent.

).  The area of zone of least biological value, expressed  in
    relative terns of population densities, would  be  trie  optrn.il
    location for an intake structure in  order to  reduce adverse
    environmental impact.

This  Is not a precise method bec<:-ise of  Inexactness of differen-
tiating relative value between species and difficulties  in
comparing importance of loss between et;f>s, larvae, and adults.
Also, It  Is assumed that the adverse Impact on  the populations
of critical aquatic orRan isms  is significant  to sone  decree  .ind
therefore, it is desirable to minimize this  impact, thus  ;; ivinr.
importance, to best available  intake locations.

If one can determine that one species  is nore  Important  than
another, one can wei^h it in some way.   If not, least  concentra-
tions of critical aquatic organisms  in any one  location  In^ic.ite
its intrinsic suitability for  intake structure  location.

A step-by-step procedure could include:

      1.  Select critical aquatic organisms; and

      2.  Divide water body segment  into  spatial compartments  (use
         hydrologlcal model).

For each species and spatial compartment:

      1.  Determine life stages potentially involved with  intake
         and type of Involvement (entrapnent,  impingement,  entrain-

      2.  F.stlmate nunbcrs of organisms  Involved at representative
         times durinp, the annual operation cycle;

j.  K.stlmatc numbers of those involved tnjt are l>>st (detcr-i-.c
    percent survival or .lortality of those entrained or inp t-if.iv.)
    on an annual basis;

i*.  Kstimate conversion ratios to express ep^s jiui l.irvjc lost
    in terns of mnber of adults (this is a value judgment .~inii
    assumes the loss of one egx is not as important to surviv.ii
    of the species as the Loss of an .idult).;

5.  Develop the data matrix for construction of the biologic.il
    value level overlay charts (Table 1);

6.  Construct transparent overlays for each species on ch.irt of
    water body segment.  Areas of different impact in terns  of
    organisms lost due to involvement with the  intake structuri'
    could be color-coded; e.p,., areas of -lost value could bu J.irK
    gray; areas of  least value, clear.  f.cnerally, three  levels
    of value will suffice;

7.  Superimpose overlays for all representative  important species
    on chart to obtain compositive value, indicated by relative
    color, for all spatial compartments  in the  water body
    segment; and

8.  Analyze graphic display of relative value and  identify
    light-toned areas as most favorable  intake  sites, heavy
    areas as lease favorable.

The methodology is  intended to be flexible.  Various snades
of different colors could indicate comparative  value between
selected species or variations In density with  depth.  The
value grades could be expressed In terms of their  relation
to populations of critical aquatic organisms  In  the overall  water
body to provide inslp.ht on importance of the specific segment
studies to the whole system.

The biological value concept for analyzing survey  data in  the
determlnacIon of best technology available to nlnimlze adverse
environmental Impact appears to have  the principal application  in
selection of the minimal imact zones  for  locating  the  int.tkf
structure.  The usability of the concept  is, of  course, d.it.i-
dependent.  As noted, it Is not precise, but at  least  integrates
multiple factors and presents a defined  indication of suitability
for location of an  Intake structure  In the affected water  body

Three-dimensional computer graphic techniques can  also be
applied to portray spatial and temporal  distribution of biological
data. 10t"

Tloe-series graphs can be useful in depicting the dynamic
nature of occurrence and abundance of a designated species
during the annual operating cycle of the intake structure.
The principal application would appear to be in the deter-
mination of the optimal location of the intake structure.
Also, graphic representations of the biologically predicted
mathematical model output could assist in more clearly
depicting intake structure impact on populations of Repre-
sentative Important Species (RIS).


              TABI.K 1


            (SPECIES 1)
            (SPATIAL COMPARTMENT  (A))

Kntra Inoent
Total Effect
Organism Involved



Z Lost
(If assuned other
than 100 2)



c. •



Calculated Equiva-
lent Adul t Loss






       The concept of a 316(b) Technical  Guidance Manual was initiated
by an interagency working group comprised  of James Truchan, Michigan
Department of Natural  Resources;  Howard McCormick and Alan Beck, U.S.
Environmental  Protection Agency;  and Phillip Cota,  U.S.  Nuclear
Regulatory Commission.  The first  draft of the Manual was  completed
in December 1975,  followed  by a  revised  version  in  April  1976.

     The  Manual  in its present form  is the product of the following
individuals  who provided comments  and assistance:   James Truchan and
Robert Courchalne.  Michigan Department of Natural Resources;
W. Lawrence Ramsey, Maryland Department of Natural Resources; Allan
Reck, Alan Seers, William Brungs, Stephen Bugbee, William Jordan,
Tom Larsen, Harvey Lunenfeld, Howard McCormick, Gary Milburn, Eric
Schneider,  and Lee Tebo, U.S.  Environmental  Protectinn Agency;
Thomas Cain,  Phillip Coca,  Bennett  Harless, and Michael  Masnik,
U.S.  Nuclear Regulatory Agency; Phillip Goodyear,  Mark Maher,
and Roy Irwin, U.S.  Fish and Wildlife Service; William  Anderson  II,
Hunton,  Williams,  Gay & Gibson;  J.  Roy  Spradley, Jr., National
Association of Electric Companies, Charles Coutant;  Oak  Ridge National
Laboratories;  Rajendra Sharma,  Argonne  Laboratories, Saul Saila,
University  of  Rhode Island,  George  Mathiessen,  Marine Research  Inc.;
and Gerald Zar, Northern Illinois University.

     Special acknowledgment goes  to Howard Zar, U.S. Environmental
Protection  Agency,  who was responsible for reviewing  and incorporating
comments   received into  this  Manual.

     Overall coordination and  preparation  of this  Manual  was  done
by the Industrial  Permits Branch, Permits Division,  Office of
Enforcement, U.S. EPA, Washington, D.C.



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