HomeMy WebLinkAboutSUS326Introduction
To An
INSTREM-1 FLOti STUDY PLAN
For The
PROPOS ED SUSITNA HYD ROELECTRIC PROJECT
DRAFT
E. tioody Trihey
Pr epared for
Acres American Inc.
Bu ffalo , New York
Ma y 31, 1 981
E. WOODY TRIHEY, P.E.
HYORAU U C ENGINEER
June 14 , 1981
Mr . Kevin Young , Environmental Coordinator
Su sitna Hydroelectric Project
Acres American, Inc.
Liberty Bank Building
Main at Court
Buffalo , N~w York 14202
Dear Kevin :
P.O. BOX 10 -1774
ANCHORAGE, ALASKA 995 II
(9 0 7) 345-0800
Enclosed is the preliminary draft of an instream flow study plan for the
Susitna hydroelectric project . ~his report is submitted a s the final product
of Task 3 r efer e nced in Mr. Hayden 's l etter to me dated March 2, 1 981 .
The draft study plan is intended to introduce the concept of an instream f l ow
assessment and outline several philosophical and technical aspects of an
assessment wh jch would be app licable t o the proposed Susitna hydroele ctric
project . Thus, this draft study plan should stimulate discussion and produce
decisions at two importa nt l evels .
Following internal r evi ew , th~ draft can be submitted to APA , F'ERC and the
p ro ject 's Steering Committee and Adviso ry Group . Their comments will be most
v aluable when deciding what to do after ~·larch 1982 . Of more immediate interest
however i s the coordination of pertinent subtasks of the ongoing engineering
and environmental studies . I believe thi s can bes t be accomplished at the
middl e -manag ~men t level .
Table 1 of t he draft study plai, summarizes my views concerning the likelihood
of the output from the ongoing engineer ing a nd environmental studies satisfying
tl-.~ e xpectations of FERC and Alaska's r escurce and regulatory agencies . It is
my opinion that sev eral questions documented in the January instream flow
survey can be addressed . In fact , a great deal can be accomplished by Harch
1982 t-1hich could b e included in a license application . Howe ver, this work
would principa lly serve to indicate what additional stud ies must be undertaken
in concert with the FERC license r e view process .
During the next two o,1eeks I will concentrate on deve loping the specific
statements and recommendations needed c.o implement. the modifications suggested
in Table l.
Sincerely ,
Trihey , P .E .
II'IISTREAM FLOW AND RIVERINE HABITAT ASSESSMENTS
INTRODUCTI0:-.1
In November 1979 the Alaska Power Authority (APA) conc~acted with Acre s
American Inc. to undercake a feasibility scudy percaining to the devel-
opment of a major !lydroelectric project on the S•Jsitna River and to
pre!)are a license ap?lication for submission co the Federal Energy
Regulatory Corranission (FERCl .
A ma jo r component of the Ap plication for License is an Environmental
Report (Exhibit E). In part . this report must provide a general but
comprehensive description of the aquatic environment of the project area
and must present sufficient basel ine streamflow and water quality data
for determining project effects on normal and seasonal variability. The
Environmental Report muse also include a discussion of project effects
on exiscin ~ instream flow uses and on any e xisting or p roposed uses of
project water fo r irrigation, d o mestic a~d industrial supplies, or other
purposes. Additionally, any proposed mitigative , enhancement, or
proteccive measures t o offset the i.r.lpact:s e::-:pected during construction
and operation of the project are to be disc~ssed . The mitigation plan
must be prepared in consulta tion with approp::iate state and feder al
regulatory and reso·.1rce mana']eme nt agencies. The applicar:t is not
req uired to accept the mitigation proposal of any a gency . However , i:
the app licant r e j ects any measures r ecomme nded by an agency , t he a ppli-
ca:1.t must submit a written explanatio n of the basis for the r ejecti on
and a description of the applicant's alternative to the agency r ecom-
mendation.
In o r der to me et these requirements, it i s first necessar y to identify
a nd evaluate baseline streamflow and water quality conditions as well as
the nature and e x tent of both existing and anticipated uses of stream-
flows in the proJect area . The pre-p roi ect a quatic and terrestrial
resources like ly to be affected by the proposed development must be
characterized and seasonal habitat requirements defined . Following the
acquisition and assembl y of these data and information, a comprehensive
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instream flo~; assessment would b e unde r taken in order to develop and
assemble the technical information needed to substantiate the dis-
cussions , impact s ta temen ts , and mitigation proposals required in
Exhibit E .
An instream flow assessment is a technical s tudy undertaken to determine
the effects of incremental changes in s:treamflow on various instr eam
u ses . Under a some1o~hat broader definition , the assessment would include
an eval uation of the effects of incremental changes i n sedimeut l oad ,
thermal regime, and water q u a lity on instream uses . Instream use s are
uses made of the streamflo1" while it r emains in the stream channel as
opposed to uses made of water out of the channel . Traditiondl ins tream
uses include hydroelectric power generation , navigation (commercial or
recreational), and 1vaste load assimilation (receiving water standar ds).
Additional uses of strearnflows that have mo~e currently been r ecognized
as potential instream fl ow considerations are: (1) downstr eam deliver y
requirements to satis.:y existing treaties, compacts , or water rights;
( 2) freshwater r ecruitment to estuaries; ( 3) water r equirenents for
riparian vegetation, fish and wildlife habitats , and r iver-based r •"cr~
ation; and (4) the amount and t iming of streamflow required t o ma Ln tain
desirable characteristics of the r iver itself (width/depth r atios,
sediment and thermal r egimes , channel gradient , riffle/pool ratio , reach
velocity, etc .).
The specific focus and degree of analysis involved in the instr eam floi·J
assessment will to a large extent depend u pon the nature of the exi:;ting
and proposed uses, and on the concerns of l ocal citizens , public
interest groups , and government agencies regarding the trade offs that
are likely to occur between the s e uses . A~; a part of APA ' s public
participation progr;:un , a survey of federill and state agencies , public
interest groups, and native corporations was undertaken in mid-January
1981 (Dwight and Trihey 1981). Interviews were conducted in order to
obtain a first-hand ~ ~ression of the l eve l of understanding and
interest of these g roups in the proposed Susitna hydroelectric project ,
and to record specific ques t ions and concerns which the respoudents felt
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11eeded to be addressed by an instream flow assessment. An attempt "'as
also made to identify specific data and in~ormational needs of state and
federal a9encies charged with issuing permits and/or reviewing the
license application or environmental impact statements . Results of that
survey have served as a principal source for the preparation of this
introduction to the instream flow study plan for the proposed Susitna
hydroelectric project .
Conceptually , the instream flow assessment will consist of three sequen-
tial pa::-ts: (A) issue identification and baseline data analysis; (B)
impact analys is; and (C) mitigation pla:;ning . This document pertai:-:s
primarily to the first part o= the in stream f!O'ov assessment, "issue
identification and baseline investigations ." No attempt has been made
to define the scope or speci fie subtasks of the impact analysis and
mitigation planning components of the instream flow asses ~me nt in this
introduction . Thut detail will be provided in subsequent docw~~nts when
sufficient background information and insights have been obtaine ~ fr om
the ongoing engineering and environmental studies .
The purpose of thi s introductory report is simply to identif! the scope
and du::-ation of the instream flow assessment being recommended , and to
provide a framewo rk for coordinating selected elements of the ongoing
engineering and environmental s tudies (Acres American Inc. 1 980 , Alaska
Department of Fi s h and Game 1981) to :
(1) provide conclusive statements by !-larch 198: for some of the
questl.ons documented in the instream flow survey;
(2) provide preliminary statements by :-tarch 1982 for the rema1.n1ng
questions documented in t he instream flow survey; and
(J) determine
addressed
those
~·ithin
assessmenL.
questions and
t he context of
concerns which should be
a detailed ins tream flow
The l ength of time r equired to complete the instream flow assessment is
influenced by several key factors: its comprehensive scope; the lack of
requisite base line data and information on instream use s and resources
in t he project area; the sequence in which several important questions
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must be answered; the complex nature of th·~ river system being analyzed;
the necessity (FERC requirement) to involve n~~erous state and federal
agencies; 1\PA's desire to ir.vvlve public and private interest groups;
and the tL~e required for r eport p rep aration and decision making .
Consequently the minimum t:ime req uired for comple t.ing the instreara flo·.-
assessment is expected to be five years . However , an Application f o r
License could be submitted by the applicant and acceoted by the FERC
prior to comp leting the in stream flow assessment. FERC ' s licensing
p rocess , which itself is likely to require 2 to 3 years to complete,
could be initiated as early as 1983 and would proceed concurrently with
the instream flo w assessment . Give n the necessary leve l of funding , a
sequence of credible i mpact statements coul d be determined by t he
instrearn f loo.v assessmen t by 1985 . Ho·.:ever, it i s not ex p ected that the
applicar:t and all potentia! interveners (resource/regulatory a gencies
and spec~al interest groups) will be in agreement much before 19a7 on a
final mitigation plan , nonitoring program , and operational constraint:s
pertinent t o the proposed project . It i s expected that attainment of
this much needed agreement c ould b e expedite d through the direct parti;i-
pation of the resource and r egulatorj· agencies in t he i:1stre am flc~:
assessment . It •.-Jould be particularly advantageous to func an inter-
agency task f o rce to participate in the analysis and author the instream
flo•.-J r eports . This action would provide a cadrf> of agency personne l
familiar .,.,ith the t echnical detail of the assessment and the basis for
the concluding statements in the various reports .
!·lany diverse que~tions have been, and will continue to be , raised
concerning the anticipated etfects of the proposed Susitna hydroelectric
project on instream uses and resources. Each ques~io~ should be taken
seriously anc ans-.:cred with a c onclus ive statement . However, the degree
of investigat i on and dnalysis required before a statement is acce?~ed as
cc:1clusive should de;J~nd to some extent on the consequences that an
error in judgement would have on the inst.ream use or resource o:
concern. To d e termine the validity of a concern and the level of
scientific analy s i~ required to develop a conclusive reply, the question
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should first be evaluated with respect to actual impacts experienced at
ot~er hyd roelect:ric p ro jects . If the question cannot be substantiated
by p revious experi.ence, it should next be considered in terms of the
uniqueness of the proposed project itself .
of these tests (previous expe rience or
project) . Viewed in this context, some
If the question fails both
uniqueness of the proposed
questions can be answered
conclu sively by March 1982 , on the basis of the engineering and environ-
m ~ntal studies i n p ro9ress . Others cannot even be addressed until mere
data are collected and several intermediate level answers are obtained .
A conclusive statement negating the concern can probably be offered on
the basis of information contained in the literature or derived from a
prelimina:ry level of analysis.
Table 1 presents several ques tions pertainir.g to effects of the p ro ~sed
Susitr.a hydroe l ect ric project on instream uses and resources . The
sequence in which the various subject areas and questions are introduced
in this t able indica tes t!':eir relative irnpo:rtance within the framew-ork
of the envis1oned ins tream :low assessment . This "impo rtance" reflects
both t he level o: interes: ir. the subject area derncns=rated by r espon-
dents t o the instreaw flo·,. sur·;ey (l)'.:ight and Trihey 198 1) and the
a~ount of change and t he sig nificance ot the impacts expected to occur
as a result of the project . The likelihood of the march 1982 answers to
the q u es tions beinq acceptable to the resource and regulatory agencies
reviewing the Application for License i s also indicated . Thi s "accepta-
bility" is bused upon the "importance" of the question and the level of
confidence a tcchnicul audience is likely to have in a statement based
upon the Harch 1982 results of pe r tinent subtasks of the feasibility
study . Each question ~as considered with respect to the engineering and
environmental studies in p r ogress as of ~ay 31 , 1 981 t hen placed in one
of the f oJ lO\olin g categories :
1 . The antici;..>ated :·!arch 1982 answer would p r obably be accepted
as C:t..'HC.t u~ { ve by r esource and regulatory agencies !l'i..t.:zc:Lt.
mcdi.,~i..ca.ti..c,z of the ongoing engineeri:1g and/or en\•ironmental
studio?s .
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2 . The anticipated March 1 982 answer would probably b e accepted
as c.oac.lu,·~-t\!1?. by resource and regulatory agencies 6oUoct•.tng
modi6-tc.a.-uon of the ongoing engineering and environmental
studies.
3. The anticipated March 1 98~ answer would probably be accepted
as pJt<U'J.mi.naJtlj by resource and regulatory agencies c&..tlwu.,t
modi6.i.c.a.-Uoa of the ongoing engineering and/or environmental
studies.
4 . The anticipated }!arch 1982 ans\ver would probably be accepted
as pJteLi.mtHMlj by resource and regulatory agencies 6oUOlt'.tng
modi6.i.c.a.-Uon of t he ongoing engineering and environmental
studies .
5 . At this time it \•JOuld not be cost-effective to undertake the
data collection and analysis required to develop a credible
response to this question .
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5'.1.-~t·,-o: GUC:S tl C ~S r cr~ un:.r. I to ~r:~ct s ~t =~c p r o;:o:;:cd Su~l:.n..J h·/drocl·-~tCl.~ :Jt'"0'4 ' ... .J:l l r:.~~:-.:a..-.J ~.i
.1nd :-~~ou r:cs ·•1.:.!': .1n l:.~l !;;.ltb .. n o : t.hc lt~el.:.'loOd o! :nc ~!d:-c ~ lJJ;t .,n !l'.:~r !)c!n..: .. u~ ... t:~ .. ,~t,: :o :-e .;.c·~:-~·
and requl.:u:or;· a ccncle.:t .
A~cept~btl!ty o: 4 ~r=~ 19a: 3~s•e T ~~~c~
~..:pon t~e ant: ic1;:..,t~ le·J~l o! =cn!!c:!e:-:c e 1:-1
~1l~t. c f!cct. YJOuld t.~c pc OfOS~ Sas 1 ~r.a hyd~oe !cctr =.c t>rOJec~
~v~ on ~~e !ollcwtng 1~s~re~ flow r elated ~op1c5?
pro-pr oject s:reaoflo~s
flood poten:ial
FLO'<~ JU:Gl:-IE
r1~e r sta9e at a~~stre~ loca~on$ dur~nq dif~e~en: ocnths
~ckaater :rc: 1ce
ice ;~ du ~1r.9 breakup
v1nt.e : ·•at..er t.e:t:-e:-a:.cr-es L~ :.h-e rescrvo:.:-s
~o~n s ~:e4C wate~ te=pe ratu~es
w1nter ice co~dlt lO~~ (:.h1ck~~ss ~nd pcrtc~ o f ice cove~)
c!\a::ne l scoor !r= lee
d!Ufe!.s !r c-:s vu·.trr s;:>1lls
e r os1on ~ea~ br>dqe p1ers
permafros~ oelt ar.d !r es ~ heave near br1dges
9 round ~ater levels a~ r eservot:' s:.te, ~nd 1~ do~~stre~ clc~~sttc we!ls .
sprtngs , ~~d slou9h areas
st4qc a _nd sedir:'lent :lopost.tl.on at mouth ot tr1butar1~:1
the abdity of the river t o clc.>n~" itscl! o~ debrl5
cnann~l scou: cclow dAmSl~e
ri•Jer :oorphol09:1 bclo.., Ta!i<eet.n<l
bod load :r.ov~ncn': a.sSO Clolt.ed too.'l th st.or:'l '!Vents
cx1st.ir.q !is!\ po:-.ll.lt.lcr..s above ....u;c! belo w d.:t~.Slt~s
Sf)4'•'TI.l~g .1nd re4:-1 ::~ hatn~at
f:.sh p..1ssaqe 4.nc! :aqrtttorl ~h.lv1 o :--of ..-dul t:s
o ve=-rtr..:c:-tnc:: o! )u·:l•:l :.les an:! r .,;~1dcnt. .1..-!u! ::::
~C~U~ 0 ~ Sll~3tl 0~ 0 ~ 3P 3'Jn!~q ~rCJS
4"lttt 1ncuMt1()n ~nrt rl.,·J'··lr.otnn: eMr•.tn-:
out. r:.q:-~:.1 00
f oCk! ba~'! !o r r e4 :-!.::.<J 11:1:1 =-~stl.!c:'l: "'poc:lt·s
post.-p rO J(!Ct. r~!lf~rvo1r f 1s!"-.cr-y po tentt.~l
~~cl~ run~ 1n th~ lo~cr rtvnr
t he 41~!i::-o..1l.lt.t·l~ c~po1cst:,· o! the ..i• .. L.Pn.J P..tvt!r
t h t" rr~sent .. dr:ni'.tn'} .:.l:.cr .. cl.l!i.~ 1 r lC.ll.lO:\ t o r l he Su~u tn.J Rlvcr
dU:"Ui 4 botn COn~tCY C:t.lOn and or.-~rttl .Jn
level o ! C L .. :..o l·;~d Jd!O!.cs 1n th~ ~u lln~ P..tVl•r u:r.ed t.st ~l i-' c!ovnr.::rcaa
o! :he du"'.3>
::u-;p...!ndcd ~cd :.r-ent .1nd t u r !:l :.c!s ._ "/ .t t vt1 r l '>U-:> do· ... --r.~.t.r•-..lll'l L .. <C ..lt.lCr."#
~·1 ltntt.'t' lf!•J'el :i tn tho nout.h o t t "-Su .... 1:.n.a R.lv-..::r
•!O~!>.~l C ~r .. d lrodu.:..t:rl\ll \.t.l5 t:e !1 :~j0:3:otl J !..!tOC'~..}~Cd W it.h 'ht"' r r opo:;:ed
C.:l:H t O l ::.O'I'C
e!!ccts c~ pl.s c cr ru.n:.r.'l on WoJ.'t ot·r ~u..sltty dur:n1 l o w-!lo•..-t t"rl ods
Wat .tr.d ~ l o'"'t p.L1n•• .lCCC9S t.o tr .. uH l i o n.'ll rccn!4t 1on ..lnd :ltt1t.C l..1nd
di!IJ,Ot.~•l ~itC:l
recrt."l dt.lOn.:tl toaLl r.rt on the Sutatn .. , FUvt:c , Sl.dcch1.'nn•-:l n u :.d slouqhs
comn..!rc:.ill t:..lVi Q~,tl on on t.he l o •~r Sua1t.n.1 P-..l'l'i"r
~he re s~lts of the onqo1na e~c~nccrtn4 a ~d
envirct"'::~~t.al st ••dt~Si cl ~ or ~f-"..3t. c!olte.
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• .Jblo 1. s~r y o f q~~st1~r.~ ~~r~!~~~~ ~ c!f~et~ o f :he prcposed ~ust:~~ h;~~ocl~c ~~i~ ?~l~~= on !r.strc~ ~~~~
4nd r~~ourccs w1th ~n ~~!e~tl~ of ~!~ lt,cl~hood ot t hQ ~~rc~ 19a= d~~·~r be1nq 3c:eF~~ble to re sc~=~
and requla~ory aqur.cics.
Qucst~on:
~~~t effect ~~uld the proposed Sus1~a hydroelectric project
have on ~~c !ollowin~ instream flov related topics?
RIPARIA.'I ~"EC!:'I'i\TI O:l A:<D WH.OLIF£
production ot moooe browse in lower river
big game migration
habit.at and popullltions of ~~~~~All terrestri sl :nammals and furbearers
entrance o! anadron>us species into the Sus1U>a Rh•er
estuArine survival o! pinit and ch= sall!lon fr1
waterfowl production in wetlands surrounding the astuar)·
winter ice conditiong in Uppe r Cook Inlet
use of estuary by belug~ wh4les and seals
existing water r1~ht:s
prellent day out-of-sue= d.iver,,u.o:ts
RIVER BASED R£CREATI0)1
r ecreat1onal access to the Su~itr.~ River by ~ater , alr o r land
winter travel on ri~er ice cover by s:to~ oach~ne
spor t ! i~hi.n~ 4C'C'e os
recre •ttona! hun ~in9 for ~se ar.d va~er!ovl
-st•tus of t.h• Su••~na ttiv,..r ... a \lfOrl•\ cl""'"' whtt~t'Pr t>iv•r
v ild and scenic aspects of the Susltna Rlvcr
recre~ttonal oppo rtu~~tie' a ssoc Llted wtt~~n t~e ros~rvoi~s
Accep~b~lity of a ~rch l~B2 an9wcr based
upon the anticipated level of con!1dence in
the results o! the ongoing enqineertnq and
environmental studi es au of that ~a~e.
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The remainder of this document is organized bv same the instream use and
resource categories identified in Table 1. The narrative is limited to
a description of those elements of the ongoing engineering and environ-
mental studies which are pertinent to the first part (issue identifi-
cation and baseline data analysis) of the instream flow assessment. No
attempt has been made to describe studies or scheduling requirements
beyond ~~rch 1982 .
1. Flow Regime
a. pre-and post-project streamflows
b . stream temperature and ice cover
c . sediment transport and river morphology
2. Fishery Resources
a. anadromous adults
b . resident adult and juven~~~s
c. aquatic habitat
3. Water Quality
a. reservoir
b. riverine
4 . Navigation
a . commercial
b. recreational
5. Riparian Vegetation and \'lildlife
6 . Freshwater Recruitment to the Estuary
7 . Downstream \<tater Rights
8 . River Based Recreation
Pertinent subtasks of the engineering and environmental studies
described in the February 1980 Plan of Study (Acres American Inc. 1980)
and in subsequent procedures manuals (Terrestrial Environmental Special-
ists 1980, Alaska Department of Fish and Game 1 981) are refere nced in
the following sections of this report . A number of modifications to the
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work outlined in the 1980 ~5 were a pproved by the Ala&ka Power Author-
ity in March 1981 . Those modifications which are pert.:.nent to the
instream flow assessment a.r e included in the narrative. Every effort
has been made to describe relevant ;ospects of the engine ering and
environmental studies which were either •Jnderway or approved as of
Hay 31, 1981.
··10-
I-'!.OW REGIHE
The Environmental Report (Exhibit E) of the FERC Application for License
must c ontain baseline data sufficient to determine the normal and
seasonal variability of streamflows. This report must also describe the
anticipated changes in pre-project streamflows attributable to the
project and determine tte resulting environmental impacts.
Nearly twenty groups interviewed during the survey (Dwight and Trihey
1981) had questions and conunents pertaining to project effects on the
streamflow 1 temperature (includes ice) 1 and sediment regimes of the
Susitna River. Hany of these questions are associated with instream
uses of water and demonstrate that the majority· of those interviewed
rec?gnize important r e lationships exist between the streamflow, thermal,
and sediment transport characteristics of the river and a variety of in-
stream uses. Several of the questions and concerns pertaining to this
topic area are provided below:
What would the stage be at selected locations during the different
times of the year? What would the magnitude of change in flow be
unde~ post-project conditions, and how would this affect access to
t r ibutaries? What is the dampening effec~ on stream flows down-
stream? How would changes in water level affect people living near
the river (flood potential)? What is the relationship of ground-
water levels to the stream?
Would the changes in water temperature be harmful to fish? What
would be the effect of increased winter flows on icing? Would
there be a greater accumulation of ice in the upper reach, with
larger ice jams during breakup? If power demand or operation of
the reservoir required that water be dumped in winter in y ears that
the snow pack indicated a high spring runoff, would there be a
buildup of ice on the river (aufeis)? Could this be managed by
controlled releases of water under the ice?
The Alaska Railroad was particularly concerned about the effect of
annual spring flooding on bridges. They felt that although ice
jams at the bridge locations might decrease, there would be
incre ased erosion of bridge piers due to decreased silt concen-
trations and channelization of the river. Other groups are also
concerned about the effect of decreased sediment loads on scouring.
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What would be the change in channel ~haracteristics? ~fuat would be
the effect of peak flow on sediment transport and stream morph-
ology? How would the proposed project affect bedload movement
associated with storm events? What would be the effect of reducing
the sediment load, and therefore associated nutrients, on do\o'Il-
stream biota? How much sedime nt would be trappe ~ in the reservoir,
and would it have to be flushed?
Streamflows
A thorough analysis of the seasonal and long term variability of pre-
and post-project streamflows will be completed by December 1981 at two
locations on the mainstem Susi tna River. This analysis will be per-
formed by Acres American Inc. (Acres), R&M Consultants (R&H), and the
Alaska Department of Fish and Game (ADF&G) utilizing average daily
streamflow data front the U.S. Geological 3urvey (USGS) stations at Gold
Creek and Susitna Station. The naturally occurring variability among
avera3e daily , average monthly, and average annual streamflows will be
presented for the respective periods of record.
Average daily streamflows will be analyzed to ascertain the validity of
using average monthly streamflows for evaluating project effects on fish
habitat. Frequency analysis will be performed and the resultant 1-day,
7-day, 15-day, 30-day, 60-day, and 90-day low flows will be determined
for each year of record. Comparisons will be made between the 1-day ,
7-day, and 15-day low flows and between these flows and the average
monthly streamflow for the month in which they occur. The 30-, 60-and
90-day low flow values will be compared with the lowest average monthly
streamflow for the year.
Peak flows will also be analyzed. The 1-day, 3-day, 7-day and 15-day
peak streamflows will be determined for the p eriod of actual record
during the months of May through October. The ratio of peak flow to
average mo nthly flow for each month will be determined and presented by
calendar years. This information will be used to estimate project
effects on scouring of spawning are as.
-12-
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Pre-and post-project stream flow conditions will be compared at two
USGS stream gage locations: Gold Creek and Susitna Station.
-13-
Flow duration curves will be developed for each month of the year based
on average daily streamflows for the period of actual record at Gold
Creek a nd Susitna Station.
?1onth ly post-project streamflows will be generated at Gold Creek and
Susitna Station for the 1950-1980 period. Using t h ese data, monthly
flow duration curves will be derived and compared to t h e monthly pre-
project flow duration curves. Information will also be p rovided at Gold
Creek and Susitna Station indicating the estimated change in stage and
stream velocity attributable to post-project stre~~flows.
These hydrologic analyses, in conjuncti~n with those outlined in sub-
tasks 3. 04 and 3. OS of the February 1 980 Plan of" Study (Acres American
Inc. 1980), are expected to provide sufficient understanding of project
effects on the long term and seasonal streamflow characteristics of the
mainstem Susitna River to satisfy FERC license requirements. Following
completion of other Phase I studies, additional work will be required to
develop the reach-specific streamflow data required for analysis of
specific impact questions within the various fishery habitat study
reaches . Numerous staff gages are being installed at strategic
locations within the project area during Phase I by ADF&G and R&!>l as the
initial step in developing the correlation coefficients required for
generating the reach -specific streamflows.
Water Temperatures
A detailed thermal analysis of the mainstem Susitna River may be
required to determine project effects on water quality, ice conditions,
and fish habitat. However, the specific questions which need to be
addressed within these three topic areas wil l require different levels
of analy!;is. For example, the required precision of a pre-and post-
project stream t emperature model to interface with the anticipated water
quality and i ce modeling studies or to evaluate thermal effects on
rearing habitat or the migratory behavior of adult fish need only be
-14-
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Pre-and post-project stream temperatures will be evaluated at the
proposed reservoir sites and three downstream locations.
-15-
accurate to +2°C. However, a stream temperature model to provide for
the evaluation of thermal effects on immature fish or incubating fish
eggs would have to accurately forecast monthly post-project stream and
intra gravel water temperatures within one degree at one half mile
intervals from Devil Canyon to Cook Inlet. They type of intensive data
collection program necessary to develop such a model cannot be justified
on the basis of our present knowledge.
Although salmon may spawn in the mainstem Susitna River, actual spawning
areas have yet to be located. Additionally, the seasonal changes in
water temperatures within the proposed reservoirs must be estimated.
Only after one has knowledge of the locations of the mainstem spawning
areas and the general magnitude of expected changes in seasonal stream
temperatures can it be decided wh ether or not the fishery resource is
likely to be adversely affected by post-project stream temperatures.
And analysis undertaken at this time to provide more than a preliminary
statement regarding the effects of post-project stream temperatures on
the fishery resources would be unjustified.
During the Phase I feasibility study, continuous water temperature data
are being acquired by R&M n ear the proposed Watana dam site to supple-
ment the USGS data which are available for the Susitna River near
Denali, Susitna River near Cantwell, and MacLaren Rive:: near Paxson.
Collectively these data will be used as one element in a thermal
analysis to estimate average monthly water temperatures in the proposed
reservo ir for purposes of exploring the eng ineering and economic conse-
quences of multi-level power outlets.
The ADF&G aquatic habitat group will install thermographs at the Sun-
shine bridge and at their fishwheel and sonar stations above Talkeetna
and in the principal tributary streams to the Susitna River between
Portag e Creek and the Yentna River. These stream temperature data, in
conjunction with associated streamflow measurements and estimated
reservoir temperatures , will provide the necessary input for a first
level ~hermal anai ysis to ascertain whether or not additional mainstem
-16-
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l:ydraulic and ice studies are
Talkeetna which will provide
post-project streamflows on
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an initial assessment of the
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-17-
Canyon and
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temperature modeling is necessary and, if so, on what stream reach(es)
the work should be focused. This thermal analysis will be done as part
of the downstream ice modeling studies conducted by Acres.
Sediment Transport
Determination of the rate of sediment accwnulation in the proposed
reservoirs and the prediction of the associated effects on the down-
st.ream river channel morphology are being addressed at a cursory level
under subtask 3.07 of the Plan of Study (Acres American Inc. 1980).
Additional insight.s will be gained as to the likelihood of post-project
flows affecting the downstream
outlined in subtasks 3.05:
river channel morphology through work
streamflo\o/ and t"lood analyses, 3. 06:
hydraulic and ice studies, and 3.10: lower Susitna River studies.
The objective of these subtasks is an initial evaluation of the general
hydraulic characteristics of the Susitna River above Talkeetna under
pre-and post-project streamflow conditions. No quantitative statements
are expected to come from this analysis pertaining to the effects of
post-project streamflo•,,s on the pre-project river channel morphology.
However, this analysis will answer questions pertaining to the general
stability of the river channel above Talkeetna. It will also provide
the necessary insight to cost-effectively address questions pertaining
to local scour and deposition within this river segment in any follow-up
studies that may be required.
No analysis is being performed at this time regarding effects of post-
p .roject streamflows on the stream channel stability/morphology belo\"
Talkeetna. However, Rhg is obtaining seasonal aerial photo coverage of
the lower river. The ADF I.G aquatic habitat group will obtain suspended
sediment samples and determine streambed material size and composition.
Bedload movement will be sampled by R&M u•tder the direction of USGS or a
nationally recognized consultant during August 1981 at Gold Cr eek and
Sunshine brid ge, and at the mouths of the Talkeetna and Chulitna rivers.
The aerial photos and streambed material/bedload informatio n
-13-
will be used along with the results from the detailed streamflow
analysis at Susitna Station to develop a work plan for a preliminary
assessment of post-project effects on the morphology of the lower
Susitna River.
Summary
Relationships between various instream uses and streamflow, stream
temperatures, and sediment transport are well recognized (Acres American
Inc. 1980; Dwight and Trihey 1981). However, data and information to
quantify these relationships are not available to explain or discuss
project effects at more than a cursory level. Hence the immediate goal
is to rigorously analyze the available streamflow data and to undertake
the necessary field work and analysis for acquiring the insight to
identify what future studies might be required (Justified).
By Harch 1982, effects of the proposed project on pre-project streamflow
conditions will be known in terms of discharge, water surface elevation,
and average velocity at several mainstem locations. Sufficient stream
temperature data will have been collected to describe pre-p roject
conditions and determine for which river segments additional stream
temperature studies are justified. The general stability of the river
channel above Talkeetna will have been analyzed and areas of potential
scour or deposition identified. Reach specific data on streambed
material sizes and aerial photography will be available to assist with
formulating work plans for the additional studies that will be required
in the lower river.
-19-
FISHERY RESOURCES
An important component of the FERC Application for License is a docu-
mentation of the fishery resources of the project area. This report
must describe the nature of the fishery resource; the expected effects
of the proposed project on this resource; and the measures proposed by
the applicant or agencies to mitigate, enhance, or protect the r esource
if significant impact is anticipated.
The fishery report must contain a detailed description of the existing
resources of the project area including all sites directly or indirectly
affected by project activity or features. This includes the downriver
segment of the Susitna River and its tributaries, the reservoir inun-
dation areas, and aquatic systems traversed by roads or transmission
corridors . Fishery information for these imp act areas must include
seasonal fish distribution and abundance, species composition, fish
production, habitat characterization, and fish movement patterns. Also
this discussion must address, if applicable, any fish species proposed
or listed as threatened or endangered by the U.S. Fish and Wildlife
Service (USF~'lS) or National Marine Fisheries Service (NMFS).
A major category of conce rn e xpr essed in the recently completed survey
(Dwight and Trihey 1981) was the effects of the post-project flow regine
on the fisher y resources of the Susitna River basin. One third of the
comments in that re port focused on this aspect:
vlould there be enough water to support existing fish populations?
Would the reduction of peak flows affect fishery utilization of
side channels and backwater areas? How many slougt.s, oxbows, and
side channels ~ould be dewatered or have limited access? How would
changes in flow regime affect · spawning, intradrainage movement,
outmigration, and seasonal habitat use? ~'lould higher stream
velocities associated with increased winter flo-v1s affect young-of-
the-year that migrate into the mainstem from tributaries during
winter months? What overwintering of anadromous juvenile and
resident fish occurs in the main channel and how would it be
affected?
-20-
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Fishery investigations will b e conducted from Cook Inlet t o the Tyone
River.
-21-
Currently a n i r ldequate information base on t he fishery resources of t h e
Susitna River drainage prohibits the preparation of answers to such
valid q uestions and concerns. In order to gather the necessary dat a,
APA has contracted with ADF&G to conduct a f ive year fishery investi -
gations program. The first phase of the ADF &G study is underway and
will culminate with t h e preparation of a r eport in spring 1982. This
report will provide a compilation of the knowledge gained about t he
fishery resources in the project area based on their 1981 fie ld investi-
gations.
Three field i nves tigations are currently being conducted b y ADF &G:
anadromous adult, residen t and juvenile, and aquatic habitat. A
detailed procedures manual has recently been prepared for each of these
investigations. A brief sununary of the ADF&G's 1981 field p r ogram i s
provided below .
Anadromous Adult I nvestigations
The primary objective of this study is to d e termine the seasonal distri-
bution and abundance of the anadromo u s fis h in the project area, particu -
larly t h e timi ng of mi g r ations and s p awning. Three major subtasks are
involved:
1. Enumerate and characte rize the fish runs.
2. Determine the timing and nature of migration, milling, and
spawning activities .
3. Identify spawning areas in subreaches of the mainstem ,
sloughs, side channels, and tributary areas which are likely
to be affected by post-project flows and estimate their
comparative importance.
Resea rch techniques for the s e subtasks include u s e of fish wheel s in the
mainstem and large tributaries, and cree l census, electrofishing ,
seining, and aerial and foot s urveys. In format i on t o be collected will
inc lude sexual maturity, p arasite load, meristic data , and a ge .
-22-
Attempts will be made to condu.ct stock separation studies utilizing
scale or tissue samples. Estimates of the magnitude of the run to
various reaches or tributaries will be performed by mark/recap ture
studies, sonar counts, aerial or feet surveys of spawning grounds, and
carcass counts.
Information on the timing of the s p a\o'l'ling runs and the migratory cor-
ridors utilized by each species of anadromous fish inhabiting the
project area will be required to accurately identify the effects of
altered streamflows or other project-related impacts. This knowledge
will be gained by several techniques: evaluation of Cook Inlet com-
mercial harvest records , determination of collection rates at fish
wheels, evaluation of data collected at sonar counter stations and of
creel census data, aerial or ground observations, examination of morpho -
logical characteristics of maturing adults captured in certain portions
of the river, and radio tracking studies. Various efforts will be made
to determine timing of spawning, and characteristics of spawning hahi-
tats. The milling behavior of adult salmon in the river segment between
Devil Canyon and Talkee tna will be examined, primarily through radio-
telemetry studies.
Resident Adult and Juvenile Investigations
The objective of this study is to determine t~e seasonal distribution,
abundance, and movement patterns of r esident adult and j u venile fish in
the project area. Two major subtasks are involved:
1 . Obtain species type , abundance, age class, and habitat utili-
zation in formation for captured fish and describe seasonal
movement patterns.
2 . Identi fy s p awni n g grounds of resident adultF and important
seasonal habitats of anadromous and r es ident juveniles. Focus
observation and collection efforts on specific reaches of the
mainstcm, sloughs, side channels, tributaries , lakes, and
ponds.
-23-
The juvenile stage is a critical portion of the life cycle of anadromous
fish in the project area. The use of habitat by these immature fis h
according to species, season of year, and location in the watershed will
be assessed in order to determine the effects of project-induced stream-
flow change or other impacts on continued successful propagation of
these species. Field study methods will include measuring catch rates
of fish by use of minnow trap s, electrofishing, smelt traps, and tag/
recapture studies. Data obtained also will be used to determine which
habitat types in the project area are of major importance to j uvenile
fish on a seasonal basis. Particular attention and emphasis wi ll be
placed upon identifying important habitats in the mainstem.
Resident adults will be studied by gillnetting, electro fishing, trap-
ping, and creel census. Although less exploited by man than anadromous
adults, resident species (primarily rainbow trout, grayling, Dolly
Varden and burbot) are a major component of the fishery resources in t he
upper portion of the Susitna River basin.
Aouatic Habitat Investigations
The habitat requirements of all fish inhabiting the project area must be
determined in order to evaluate the nature and magnitude of project-
related impacts and to develop appropriate mitigation proposals. The
objective of t his study is to work closely with field personnel in the
anadromous adult and re s ide nt adult and juvenile study teams to locate
and characterize various habitat types being utilized b y all fish in the
project area.
Descriptions of the general range of streamflow-dependent physical and
chemical characteristics which appear to b e influencing the suitability
of habitat for the species and life history stages of interest will be
compiled. Preliminary assessments will be made of the physical and
chemical characteristics of fish habitats and the character and quantity
of habitat available under variou ~ streamflows. Streamflow staff gages
and thermog raphs will be depl oye d and monitvred throughout the proj e ct
-24-
area. Water quality data also will be gathered by ADF &G according to a
predetermined s a mpling schedule in conjunction with water quality
investigations of the U.S. Geological Survey .
Summary
Information obtained from these fishery investigations, in concert with
data obtained from many other research efforts, will be utilized by
Terrestrial Environmental Specialists, Inc. (TES) to prepare an initial
report describing the overall effects of the proposed Susitna hydro-
electric project on the fishery resources of the watershed. Quantifi-
cation of project effects, particularly with regard to altered stream-
flows, is perhaps the most important fishery question which needs to be
answered. The data base available by spring 1982 for addressing this
question will not be sufficient to supp ort a definitive answer. How-
ever, TES should be able to identify many of the generic impacts which
are likely to occur and estimate their relative magnitude. But a
quantitative assessment of the degree necessary to identify a recom-
mended stream flow regime for the protection and preservation of the
existing fi s hery resources or to formulate mitigation measures cannot be
prepared . Thus, the data base and preliminary assessment of anticipated
impacts availab le in March 198 2 will only form the basis and framework
of a study plan for a comprehensive instream flow assessment to be
conducted during the ensuing years.
-25-
WATER QUALITY
The FERC Application for License is to contain a report on water
quality. The report must discuss water quality and contain baseline
data sufficient to determine the normal and seasonal variability, the
impacts expected during construction and operation, and any mitigative,
enhancement, and protective measures proposed.
The report must include a description of existing water quality in
sufficient detail to determine seasonal, vertical, and horizontal
variation as appropriate for streams, lakes, and reservoirs. The
description must include measurements of significant ions, chlorophyll
a, nutrients, specific conductance, pH, total dissolved solids, total
alkalinity, total hardness, dissolved oxygen, bacteria,
suspended sediments, turbidity, and vertical illumination.
temperature,
Information
on the surface area, volume, maximum depth, mean depth, flushing rate,
and length of shoreline of the proposed reservoirs must be provided .
The gradient and type of substrate present in the stream reach to be
inundated by the proposed reservoir must also be provided in the report.
A quantification of the anticipated impacts of the proposed construction
and operation on downstream water quality, such as thermal regime,
turbidity, and nutrient level, and a description of measures recommended
by federal and state agencies and the applicant for the purpose of
protecting or improving water quality during project construction and
operation must be contained in the report. An explanation of why the
applicant has rejected any measures recommended by an agency for the
protection or improvement of water quality, and a description of the
applicant's alternative measures to protect or improve water quality,
must also be included.
During the conduct of the instream flow survey (Dwight and Trihey
1981) , agency concerns associated with post-project water quality
effects downstream from the reservoir on future users were documented.
-26-
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Assimilative Capacity will be determined at two locations on the
mainstem River.
-27-
The Alaska Department of Environmental Conservation (DEC)
questioned the general effects of the proposed change in flow
regime on the assimilative capacity of the Susitna River. Both the
sediment and thermal regimes of the Susitna River are expected to
change. Thus, future discharge permit applicants might be required
to incur additional treatment costs before meeting Alaska's water
quality standards. In a somewhat similar fashion, the U.S. Army
Corps of Engineers (USACE) indicated an interest in having t he
anticipated post-project flow regimes reviewed with respect to the
~anting of 4 04 permits to the post-project applicants . The
interests of both agencies were accented b y renewed discussion of
the capital move . Alaskans for Alternative Energy and ADF&G's Su
Hydro Team also mentioned the capital move and questioned the
effects of post-project flows on d o mestic and industrial waste
disposal.
The principal water quality analyses undertaken to date are intended to
estimate the magnitude of the seasonal changes anticipated in suspended
sediment, water temperature, dissolved gases, and chemical constituents
within the proposed icpoundments. Acres is performing this analysis
utilizing streamflow and water quality data collected by USGS and R&H.
In response to the question raised by DEC and USACE , R&~1 will estimate
the effects cf post-project streamflows on the seasonal assimilative
capacity (BOD and COD) of the Susitna River at Gold Creek and Susitna
Station. If these preliminary analyses indicate additional water
quality data and anal ysis are required before a definitive statement can
be provided, an app ropriate work plan will be developed and imp l emented
during mid 1 982.
Summary
The principul water quality analysis will focus on dete rmining seasonal
post-project conditio ns within the impoundments. Only a p reliminary
estimate of the seasonal cha n ges anticipated in suspended sediment,
water temperatur e , and
estimates will provide
;ol ved gases i s expected. However, these
_ght as to the likelihood of post-project
water qua lity conditions being harmful to the fishery resources.
-28-
The evaluation of effects of the post-project flow regime on the assimi-
lative capacity of the Susitna River at Gold Creek and Susitna Station
will either answer the questions raised by DEC and USACE or determine
what additional data and analysis are r equired before a definitive
statement can be provided.
-29-
NAVIGATION
Conunercial
Based upon the findings of the instream flow survey (Dwight and Trihey
1981) , it is unlikely that post-project streamflows will have any
affect, either positive or negative, on conunercial navigation in t he
lower Susitna River. The Alaska Department of Transportation and Public
Facilities was not aware of any conunercial navigation on the river. The
Bureau of Land Managemen':. (BUI) District Office also indicated that
commercial navigation was not an instream use on the Susitna River. The
u.s. Coast Guard stated that the head of navigation is defined as being
at Gold Creek . They do not maintain any navigational aids downstream
from this point and have no jurisdictional concern for structures
proposed upstream from Gold Creek .
For p urposes of addressing project effects on this "use" in the Appli-
cation for License, TES will provide a brief narrative on the history of
conunercial navigation on the Susi tna River and the likelihood of it
being developed in the for eseeable future. The TES essay will be
reviewed by the Susitna Hydroelectric Project Steering Committee prior
to being included in the documentation for license application.
Recreational
Questions identified in the instream flow survey which pertain to
anticipated effects of the p roposed project on recreational navigation
fall into two major areds: 1) access to the river by water, air , and
land , and 2) movement within the river itself:
Boat and float plane access to side channels and small tributaries
and to the west side of the lower Susit~a River was questioned by
USFWS's Fishery Resources Program, the Fairbanks Environmental
Center, and ADF&G' s Su Hydro Team. The Anchorage Fish and Game
Advisory Committee and NMFS were concerned about sport fishing
access, pr imarily downstream from Talkeetna. The Sierra Club's
Knik Gr oup asked whether recreational access, in general, would be
-30-
reduced or enhanced. The main concern of the Alaska De partment of
Natural Resources (DNR) was whether or not stream flow alteration
would affect access to land disposal sites.
The Sierra Club's National Representative was specifically con-
cerned about project related effects on whitewater boating
(kayaking, boating, and rafting) between the Denali Highway and
Talkeetna. Trustees for Alaska questioned whether movement within
the lower Susitna River would become more hazardous as a result of
reduced summer streamflows.
Based on the level of interest and the nature of the questions con-
cerning recreational navigation, it is recommended that APA' s Appli-
cation for License contain a description of present-day use patterns
(i.e., mode, location, extent) and a preliminary discussion of the
likelihood of post-project flows altering the status quo. Toward
meeting this objective, present-day patterns, frequently used access
points (including float plane landing sites), and known recreational
navigation corridors need to be identified. A navigation user needs
survey, such as that suggested by DNR's Water Management Section (Harle
1980) , might be the most cost effective means of documenting present-day
use patterns and user attitudes a n d preferences.
As a minimum, TES should scope out the type and level of effort that
would be required to document present-day recreational navigation use
patterns in the lower Susitna River. Maps and photographs conveying
this information should accompany APA' s Application for License. By
supplementing th':! Phase I engineering and hydrologic studies (Acres
American Inc . 1980) with site-or reach-specific water surface ele-
vations determined from staff gage readings, the likelihood of post-
project flows adversely affecting recreational navigation can be dis-
cussed by March 1982. If warranted, Phase II hydrologic and/or engin-
eering studies could be outlined to estimate the magnitude of post-
project impacts on recreational navigation (access or movement) within
principal use areas.
-31-
RIPARIAN VEGETATION AND WILDLIFE
Although a number of groups contacted during the survey (Dwight and
Trihey 1981) acknowledged that riparian vegetation is important, there
were few specific questions raised. The major concerns focused on
whether or not post-project flows would maintain a disturbed enviro nment
conducive to the production of moose browse.
The effect of post-project flows on maintaining moose habitat in the
lower reaches of the Susitna River was often mentioned as a possible
impact on hunting, as were the effects of post-project flows on boat
access to the hunting areas. The USFliS' s Western Alaska Ecological
Services questioned whether flows to maintain early seral stages of
vegetation would need to be designed into the project operation as part
of the mitigation plan. However, the U.S. Soil Conservation Service
(SCS) felt this would not be necessary, as riparian vegetation would
readjust to post-project conditions. Furthermore, SCS was doubtful
whether project-induced vegetation changes below the Chulitna River
would be measurable.
This topic area will need to be considered at a later date in con-
junction with proposed ice and sediment transport studies.
-32-
FRESHiiATER RECRUIT~tEN·r TO THE ESTUARY
The proposed Susitna hydroe lectric project will not affect the long-term
average annual freshwater inflow into upper Cook Inlet. However, the
seasonal variability and timing of the inflows will be altered.. The
extensive analysis of pre-and post-project streamflows , which will be
undertaken by Acres, R&M, and ADF&G (refer to streamflow subtask of Flow
Regime section) at Sus{tna Station, will provide an adequate basis for
quantifying the amount of change in seasonal variability and timing of
freshwater inflow to the estuary .
Such analysis mig ht also provide sufficient insight to determine the
likelihood of post-project flows resulting in a · significant change in
the estuarine environments, particularly if any relationships could be
documented in the literature r eferencing Upper Cook Inlet commercial
salmon catches of escap ements, waterfowl hatching success, or biologic
conditions within the upp er estuary itself to low-flow con ditions in the
Susitna River.
-33-
DOWNSTREAM WATER RIGHTS
The Appli ~~tion for License must evaluate the anticipated effects of t he
proposed Susitna hydroelectric project on existing instream uses and
identify both existing and proposed uses of project water for irri-
gation, domestic and industrial supplies, or other purposes.
The survey report (Dwight and Trihey 1981) identified the following
concerns:
A fundamental question asked by the Alaska Miners Association a nd
ADF&G's Su Hydro Team was "what permitted or licensed water use
rights prese:1tly exist in the Susitna River basin?" Two additional
questions raised by ADF&G' s S1,1 Hydro Team ·and Susitna Power Now
were 1) whether operation of the dam would allow present day
out-of-stream diversions to be maintained, and 2) whether post-
project flows would result in a change of water table conditions
that would adversely affect domestic wells or surface water sup-
plies. DNR's Water Management Section staff indicated that Susitna
River basin water rights applications had not been adjudicated, but
doubted that any existing out-of-stream diversions would be
affected by the proposed Susitna hydroelectr ic project.
Nonetheless, existing water rights should be identified as a subtask of
the instream flow as sessment. Pursuant to AS 46.15. 080 (criteria for
issuance of permit), DNR will r equire this information before isst.ing
water rights permits and reservations of water for the proposed Susitna
h y droelectric project. In addition, AS 46.15.145 (reservation of wate r)
provides for the reservation of streamflows or water levels for the
purposes of l) protection of fish and wildlife habitat, migration, and
propagation, 2) recreation and park purposes, 3) navigation and trans -
portation purpo3es, and 4) sanitary and water quality purposes. DNR 's
Water Manageme_n t Section is currently developing rules and regulations
for implementing this legislation. After July 1, 1 981, public age:1cies,
native groups and private citizens may file a request for instream flow
reservation.
The Water Management Section staff at DNR anticipates that they will
receive requests for instream flow reservations from several agencies,
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groups, and individuals due to the high visibility of the proposed
Susitna hydroelectric project. Taken collectively, these requests may
precipitate the 1eed for an instream flow assessment to quantify the
streamflow requirements of all existing and proposed uses of Susitna
River water within the basin before DNR could grant APA a reservation or
water rights permit for the proposed Susitna hydroelectric project. An
instream flow assessmen t undertaken to determine the amount of stream-
flow required by various uses is far more costly and time consuming to
conduct than one undertaken to determine effects of a proposed develop-
ment on those uses.
Therefore it is recommended that the questions pertaining to the nature
and extent of existing water rights permits in the Susitna River basin
be answered by March 1982. It is further recommended that the head of
DNR' s Water Management Section be extended an invitation to participate
in the further development of a study plan for this element of the
instream flow assessment. DNR staff time and resources would be inte-
grated into the work plan to the extent that staff time and state
funding would allow.
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RIVER BASED RECREATION
Many groups indicated an interest in this topic, but their questions and
comments reflected preconceived personal biases rather than an objective
consideration of project effects on recreational use (Dwight and Trihey
1981).
The potential for increased recreational opportunities was recog-
nized by several groups, but both DNR' s Water Management Section
and the ADF&G's Su Hydro Team questioned the public's acceptance of
reservoir recreation as a replacement to an established riverine
use in the upper basin. The proposed reservoirs are expected to be
very deep glacial lakes with a precipitous shoreline and fluctu-
ating water surface. Such characteristics are not expected to draw
many reservoir recreationists.
Several groups, such as the U.S. Heritage, Conse ... :· ·at ion, and
Resource Service concentrated on recreational opportunities that
would be lost. Bu~'s Resources Section questioned to what extent
the aura of the wild and scenic aspects of the river would be
degraded while the Anchorage Fish and Game Advisory Committee and
ADF&G's Sport Fish Division were interested in quantifying project
impacts on fishing success . Many respondents raised questions and
offered comments pertaining to project affects on sportfishing.
In summary, then the majcr question to be answered is "To what degree
will riverine based recreation be increased or decreased as a result of
the project?" Toward answering this, both DNR' s Water Management
Section and USF~lS's Western Alaska Ecological Services felt that a
recreational user needs survey is necessary because of the level of
opposition to the project due to perceived recreational losses, and the
lack of information about what type of recreation is desirable. It is
recommended that TES contact these agencies to discuss specific objec-
tives and approaches that might make up such a survey. If their initial
discussions are fruitful, addition·al agencies and special interest
groups might be factored into a second round of discussions. The
objective of these planning sessions would be to prepare an acceptable
questionnaire, sampling technique, and evaluation procedure for a Phase
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II recreational user needs survey. A brief statement concerning the
development of the recreational user needs survay and its intended use
during the Phase II decision-making process would accompany APA's
initial request for licensing.
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REFERENCES
Acres American Inc. 1980. Susitna hydroelectric project; plan of study.
Report for Alaska Power Authority , Anchorage, AK. 1 vol.
Alaska Department of Fish and Game . 1981. Aquatic Studies Procedures
Manual, Phase I.
Dwight, L.P., and E.w-. Trihey. 1981. A survey of questions and
concerns pertaining to instream flow aspects of the proposed
Susitna hydroelectric project: a working document for preparation
of an in stream flow study plan. Report for Acres American Inc. ,
Buffalo, NY. 25 pp.
Harle, M.L. 1980. Review of Susitna hydro procedures manual. Letter
to A. Carson, Div. of Research and Development, Alaska Dept. of
Natural Resources, Anchorage, AK, September 23, 1980. 1 pp.
Terrestrial Environmental Specialists, Inc. 1980. Environmental Studies
Procedures Manuals . Prepared for Alaska Power Authority Anchorage,
Alaska.
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