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<br />I , d". <br /> <br />0022;.;7 <br /> <br />e <br /> <br />e <br /> <br />The 1977 Project operation study simulates Project operation on a <br />monthly basis tor the period 1928 through 1973. During the study <br />period, the minimum release from McPhee Dam was 78 cfs in 13 years <br />(28%), 50 cfs in 23 years (50%), and 20 cts in 10 years (22%). These <br />releases were made up of spills (water excess to the Project), water <br />released to satisfy senior downstream water rights, and Project water <br />released from storage. The study indicated that the average annual <br />amount of Project water required to be relea~ed from storage to make <br />these flows was 25,400 AF. Because the operation study is a monthly <br />model, it is not possible to simulate managed releases in place of <br />spills. The model allows the reservoir to fill and spill in an <br />uncontrolled manner. This results in much shorter spill periods with <br />higher flows than would occur in actual operation. To compensate, the <br />model did not simulate releases of 78 cts during wet years but released <br />50 cfs during both normal and wet .years and assumed the extra wate~ <br />needed for the higher flows would be offset by the longer periods of <br />managed releases in place of spills (longer periods when no Project <br />water was required to be released from storage). However, this <br />assumption is probably net-valid. When minimum releases downstream were <br />~ncreased from 50 cfs to 78 cfs during wet years, the average annual <br />volume of Project water required to meet the downstream criteria was <br />increased to 29,300 AF. This results in a discrepancy of 3,900 AF <br />between the volume of Project water reServed by the United States for <br />downstream purposes and the volume c: Preject water required to meet the <br />DPR/FES ciowns~:e~ release c=i~e=~a. <br /> <br />D, SCOPE <br /> <br />~he scope c: ~~~5 Eiclc;~ca: Assessmen~ ~s :~i~ed ~= ev~~ua~~n; ~he <br />effec~s of ~he p=cposed ac~~on desc=i~ed below and in ~he Januari :996 <br /> <br />Dra~~ Env~=o~~en~a: Asses5me~~ e~~~~lec ~?=oposal ~c Modify o?e~a~ic~ <br />M=Phee Reservc~= and Ac~~i=e Addit~onal Water for F~sh and W~ldlife <br />Purnoses. . <br /> <br />E . ALTERNAT!VES <br /> <br />Re=lamation developed anc evaluated a range of alternatives to the <br />proposed action. Only the proposed action and the no action alternative <br />a=e feas~=le fc= implemen~a~io~. <br /> <br />1. PROPOSED ACTION <br /> <br />Modify the operation of McPhee Reservoir - Recla~ation proposes to <br />modify the operation of McPhee Reservoir by changing f~om the 1977 <br />D?R/FES downstream release criteria of 78, 50, or 20 cfs ~ a managed <br />pool. c: w.a-:.er ava.:..:a~lE: ==om 5~orage fo= ciowns'treal'n release fo= :isi: and <br />wildlife purposes. hn interagency team would manage releases from the <br />pool to provide seasonally fluctuatin~ downstream flows for the benefit <br />of downstream fisr. anc w~lcl~fe resou==es. Releases would be made by <br /> <br />~wc: ~nder c.~=e=-:..:.~:: i:y ?e.cla.."T.a-cic::. For wa~e= a=co~:l~':'::; p:..:=poses, <br />=Elecses ~ill bE weas~~ec a~ ~he parshc:: =lume ins~c:lec ~~ ~he Dclc~es <br /> <br />~.~ ve:: t.elo.~' ~::?:Jee Da::.. <br /> <br />~~~s ~oc~:~=a~~c~ wo~lc =e~~~=e c sepa=a~e <br />