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14 COLORADO RIVER STORAGE PROJECT' increase its uses lUld still meet its comI?act obIigat,ions for flows, at Lee Ferry for the benefit of the lower basill and MCXICO. The estimated,total active storage capacity available ill fiscal year 2062 in the four authorized units after sediment encroachment is shown in the following table. This available capacity may be ap'pro- priately referred ;to as replacement storage capacity since it will be used, among othlir things, to replace to the lower basin an appropriate part of the naturitI streamflow consumed upstream in the upper basin during prolonged'mouth periods. Eatimated active 8torag8 capacitie8 in fiscal year ~08S (In thousand aore-feet] I Sediment deposition to end RemalDlIig Fiscal InltlBIll.ctlve ot.ll.soal year 2062 aotlve lItoMgll Unit yearer active storage cP.paoltyln, JnlMal capaolty 1lscal year storage Indol\d stor- In aotlve ster- '"'" ageC8paolty agooap90lty Glen CfUl6onu____nm._~__________ 1003 21,605 6,260 .,Illl 11,326 Flaming orlle__.__~_____;.__________ 1064 3,600 70 130 8,470 Navaho 1.._._.___._______1-.______._. 1'" 1,023 '50 80 '" Ouroc8utL ______.______ u~___.__ _ ___ 111011 720 10 20 700 TotaL.n._____ _____~-_-------- __Oh.nh 26,863 1l,690 .,410 22,443 I The StOf8ll'8 o8PBOlty at the Nnva.ho unIt may be Delldlld ultlUlately by tho potontla\ Navabo IrrlgattoD project and other 10011.1 development13 and honC8 may Dot he QvaUablo to meet oomp~ct obllgtlotloDS. ThIs situation v.:1U be revIewed when tho Navabo IrrIgation project 15 l\uthorl.zed. RESERVOIR OPERA TrONS Two studies Were made of the coordinated operatiou of the four authorized units I of the storage project. The first was au initial reservoir filling study to bring the reservoirs to power operating levels and to roughly determine power production potentialities to March 31, 1971. The seco.nd was a more detailed study covering coordiuated reservoir operations to estimate anuual power production after March 31, 1971. The initial filliqg study was based on average streamflow conditions for the 32-year period 1914-45. The average flow was progressively modified throughout the filling period in accordlLnce with the projected schedule of upstream depletions. Allowances were made for reservoir evaporation nnd for increases in storage at upstrenm reservoirs, Each reservoir was first filled to the mimmum power operating level in order that power generlLtion might be obtlLined as ell.l'ly as ]lracticable. Thereafter additi~nnl stol'l1ge wns progressively accumulated at all reservoirs from a.;ailable storable supplies, The filling study indiactes thnt Gleu ClLnyon, the first reservoir scbeduled for completion, would start filling at the beginning of fiscal year 1963. All the reservglts would fill to. reasonable operating levels by March 31, 1971, and the major part of the system pnwer output at the three storage units would then be attained. Au annulLl summary of the initial filling operation for the Glen Canyon Reservoir with allownnce for filling of the storage project upstream reservoirs is shown ou the following page, The post-filling reservoir operation study was based on several repetitions of a rljnoff cycle similar to the 32-year runoff period 1914 to 1945. Data cprresponding to the 32 years in sequeuce were in- serted in the study for fiscal year 1971 through fiscal year 2002 aud the process was repeated for each 32 years therelLfter with proper adjustments for increased depletions, Annnal releases for system