|
<br />I
<br />I
<br />I
<br />I
<br />I
<br />I
<br />,'"
<br />,
<br />
<br />
<br />
<br />,
<br />,I
<br />,
<br />'I'
<br />II
<br />I
<br />I,
<br />"
<br />I:
<br />I
<br />I
<br />I
<br />
<br />when antecedent rainfall has resulted in saturated ground conditions or the
<br />ground is frozen and infiltration is minimal. Convective-type cloudburst
<br />storms, sometimes lasting for'several hours, can be expected to occur in the
<br />area during the summer. Runoff from these storms is characterized by high
<br />peak discharge, short duration and small volume [Corps of Engineers, 1980).
<br />To avoid aggravating flood stages downstream, the UVWUA historically has
<br />reduced diversions through the Tunnel so that less water is passed into the
<br />Uncompahgre. Peak discharges for the Uncompahgre River and area streams are
<br />shown in Table 2.5.
<br />
<br />'0', '
<br />, I
<br />I,
<br />
<br />Table 2.5
<br />Peak discharges in area streams
<br />
<br />Stream name
<br />
<br />10-yr
<br />
<br />50- yr
<br />
<br />100 - y r
<br />
<br />500- yr
<br />
<br />UncompahgrebRivera 3,100 4,400 5,000
<br />Cedar Creek 500880 1,250
<br />Montrose ArroyoC 300 800 1,100
<br />
<br />Notes:~: At proposed facility powerhouse site
<br />Upstream of confluence with Montrose Arroyo
<br />c. Upstream of confluence with Cedar Creek
<br />Sources: Uncompahgre River: Corps of Engineers, 1980
<br />Cedar Creek and Montrose Arroyo: Hydro-Triad,
<br />
<br />6,600
<br />3,200
<br />2,000
<br />
<br />1979
<br />
<br />2.4 Water budGet model for existinG conditions
<br />
<br />10
<br />
<br />I
<br />2.4.1 Model description
<br />
<br />A model I of the existing system was constructed in order to compare
<br />currently diverted volumes to diversion quantities for the proposed
<br />facility. The model uses water budget techniques which combine system
<br />inflows and demands to estimate the quantities of flow which would be
<br />available for power production. ' The existing system is shown in Figure 2.5,
<br />and variable names for the inflows, demands and model computational nodes
<br />are presented in Table 2.6.
<br />
<br />Since 1965, the operation of the Aspinall Unit has stabilized flows in
<br />the Gun n i.s 0 n R i v e r . B..:r;"ljl,sie,.:>!Aj~liu:a,ll f1j"S.;;m~'B'e:taj;J:.v;(H~..?Xgg:e1i'lt:aa'd'i:t::l\(l:ri:::fo; ,t he-
<br />~t.El!!li""U s,~';;;:2.fJ1;i:at,or,i~g.J;;~\J,aOO:e'Ci.d;g.Ji~j:il2;e:l'jQWI't1)'~2T\'l1TIl~l:'I'/OWl~(J mo:t':::YSe:;l:'d;-~~aAi
<br />a~l;.!!r:a t e~',!,~,~~,!! ~:$.lI)e..nhj'qft",.;1;h~7SV!"11,g.r':;"7~L!Plit'i'@. s;;y;.:a'! ~ri.l:o,bles~'Sf:or~y.Q;Yc'O'p'Owe,..
<br />PJ'.9..d'~cc.t,}.9}J;~a,:t tbe,p..r..9B.?,sed .~ci lit,y.\ . ~bJ~l:'efi5fel~:':'5jni1iJat'e(j::d<tt'a::'.\:l.e:ne~"~J.usedJ.
<br />Th..e;se ..,,: '(j.al,a,;iWe.r~. ,p r...OY.1~d'ea::llYi..l{eo:llamatJ~n ;>'=::'iln9;:w~ r~rJ1?f'~E[a~gd ,::tf!Q)Z:.:2B.\1!:\LOS e!9
<br />l:mteJa'ted..tO':.tJ'j;i.!;~.st.l!cj)l. However, the simulation model closely correlates
<br />with the annual volumes at the ~auge, as discussed later in this report.
<br />
<br />, '
<br /><;J:he:::pe 1'.4'(10':0 f:..s tudy. ,u se"dF.b y:',Re:cla.mat Mh,:!irrit?i:.t,~si,mYJ,a t"to n:Jan a:l~y,:sj's;<:~w a'll
<br />&ttober~~~1~5r~th~ough;Octobe~~~119~1. This period was used for the studies
<br />described in this report, with two exceptions. First, a calendar year
<br />format was adapted in preference to water year for ease of presentation to
<br />the public. Second, the Reclamation data were appended to include two
<br />additional years of flows, 1982 and 1983. These data were provided by the
<br />Western Area Power Administration.
<br />
<br />'LJ'
<br />I '
<br />..
<br />
<br />- 2.14 -
<br />
|