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<br />I. <br />i <br /> <br />. <br /> <br />. <br /> <br />6 <br /> <br />25 ye.r. st.lting in 1953 and had .n av.rag. flov of 12.96 MAl/y.ar at La.. <br />Ferry. The p~orr" al.o determined the probabilities of meeting or .xceeding a <br />5.8 MAl d.,letion" Th. prob.bility i. 97.96 percent b.sed on the period of <br />record. <br /> <br />2. Verification tuns - CRSS <br /> <br />S.v.ral C1SS ~od.l runs w.re mad. to v.rify the for.ula .ooro,ch a. discus.ed <br />abov.. Th. a"proach to the probl.. using tha ClSS IIOdel is sl1ghdy different <br />fro. that of using tha for.ula. Depl.eiou..n.n input to the 1I0dd r.cher <br />chan an oucput. Ie w.. tharefore nec...ary to Ip.cify . d."l.tion l.vel and <br />chen verify other ".ra_c.rs such as .horug.. and .conge used. Even clle <br />d.plecion l.vel could noc b. .pecified exactly because tile relervoir .vaporacion <br />porcion of the d."l.cion v.rie. with the operation of the r.,.rvoir aDd is <br />de"endanc on w.c.r surface .r." and ev.por.cion r.t". Another major dif- <br />fer.nee beeween the IIOdel .""ro.ch and the fot1llUla .""ro.ch 11 chat in the lIOdel <br />- just ., in the re.l vorld - the .traalllflov and the d._d. .~. both .".c1ally <br />and t..por.lly di.tribut.d; i..., th.r. may not be w.t.r .vailabl. to ...t <br />de_d. .t a given point in the Dal1n .t . given point.in t1... The formula <br />.""ro.ch, howev.r, .,.ume, that all of the v.t.r i. .vailabl. to ...t .11 of the <br />d._ds .,bove L.. F.rry. <br /> <br />au. 1IOd.l run Val made in an eUort to confitll the 5.8 M.U' C01qlut.rilH for.ala <br />run. Bank .tor.g. r.l.... w.. r.,trict.d to z.ro .nd the masimum drawdown on <br />the r...rvoirs con.tr.1n.d to lIinimum pover pool.. Th. .tor.g. used b1 the <br />~d.l w.. 20.7 MAE (v.. 26.2 MAl in the formula appro.ch) and the av.rage <br />shoreage was 264.000 A2 Iyear or 4.6 percent over the 25-ye.r critical period <br />1953-1977. Th. r..ult. of the run indicat. an actual d."l.tion obtainH of <br />5.775 MAE. If an adju.t.~nt i. mad. for the difference in .torag. valuee us.d <br />beeweer. the ewo 1IIethod.. the nuining .torage would be about 1-1/2 pereent. An <br />annual r.le..e of 8.27 MAE was made frail Lak. Pavell in this run. <br /> <br />Another ~od.l run v.. made to verify the result. of the 6.3 MAl computerized <br />formula run. Th. d.pletion l.v.l r.ach.d w.. only 6.187 HAF. short of 6.3 MAl. <br />With a tak. Powell annu.l r.l.... of 8.23 MAl and a critical period of 25 y..rs, <br />the storage used by the !ROdel w.s 27.4 MAl and the av.rage short.ge Val <br />5.7 percent. When adju.tment. .r. mad. to account for the d1ff.r.nc.s beewe.n <br />depl.tion 1.vel. and .tor.g. uI.d, the difference in shortages amount to 1... <br />than 2 "erc.nt. <br /> <br />_ The ClSS IIOdel verification run. 1 and 2 are valuable indicators that the <br />storage y1.14e in the Upp.r aasin. wh.n .tr....d. can still m..c the n.c....ry <br />d.pletion levell .nd r.main within tol.rabl. shortage.. Seve~al model runs we~. <br />mad. with varied rel..... (7.5 MAl and 8.23 MAl). with bank .torage r.le.... no <br />constraint. on active storage, etc. E.ch time, the d.pletion l.v.l reach.d in <br />the cwo method. w.re within about 1-1/2 p.rc.nt of on. anothe~. <br /> <br />Th. CRSS mod.l and methodology w.r. u.ed .xcen.ively to .tudy the .bility of <br />the Upper aalin to ma.t v.rying d.pl.t1on l.v.l demands under d1ff.r.nt <br />r...rvoir deliv.ry schedule.. The CRSS comput.~ ~odel aud correlponding <br />methodology verified that the .xiscing 5.8 MAl depletion level for the U""er <br />ColoradO River B'lin i. con.erv.tive. ~ithout .tres.ing the Opper Color.do <br />Riv.r 'Y'tell, the model gen.rates a d.pletion number that i. .pproximat.ly <br />5 p.rc.nc high.r for the Up".r Colorado River Ba.in. The higher d.pl.tion <br />