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000200 So PERIOD OF STUDY The period of study for determination of the amount of water salvageable from the Closed Busin is limited to 1936 through 1960 by the estimates of the eastern rim inflow which could be deriw'd using the llvailable discharge records~ The period of reliable' diversion records from 1928 through 1960 was used ill thcJ)ortion of the llnlllysi~ made to define the potential uses in Coloru 0 of the :-.;alvagt'able water. 'VATER AVAIL....BLE FOR SALVAGE Grcrund water All of the ground waler reaching the sulvage arell, regardless of its source, is dissipated by nonbenefici!ll cnlpotJ'IlJ1Spirntion. In lien of such nonbeneficialuse, the same amount of water could be [{'moved from the salvng:e nrNt by pumping without nffccting tlw hydrologic balance of the Closed Basin. The nonbeneficial use of ground wuter ill th- sulyugc llrCll is rf'- flected in the fluctuation of the grollnd-wuter table. The U.S. Geo- logical Survey, during their 1946-53 inve:-;tigatioIls, lll11illtained u network of obServtltion wells in nIll! adjncent to the select.ed snlvage area. Supplemented by un ndditionul 100 wplls, the obsernltions wen: continued as pilrt of t.his investigution. Tho r{'cords of these ObSf'_ITU- tion wells were carefully reviewed to select a limited number of key wells, the fluctuations 'of which were n'pres{,lltl\tivt~ of t.he g:eneI'tl.l fluctuation of tlw water tuble within till:' s(,lecteu 5lth"uge arell:. Such key wells hnd to be so locnted thnt their records would Hut refl(~ct local flu'ctuatiolls of the water table resulting from vnrious types of ::;urfaco flows. Seven wells were determined to have records rppresentntive of the genernl fluctuations of the wntpr tablt' throu~hollt t.he sulvngc luell. Drnwing 2.53-504-1832 pre.scnts a hydrograph for ',"ell .:\0. 152, which is considered repn~sentntin~. This hydrogruph shows that during the nongrowing season, when there "-as little or no enq>otrtmspiratioIl, t.he elevation of the wlltrr tltblc rose rapidly. COIl\-ersely, dnring the growing seu.....OI1, the elevation of t.he wat.er taLle diminished. By extrapolating the nvemg(' rate of rist' during tho Ilongrm....ing season throughout the growing s{'!lSOIl, nnd (~OITN:ting for till' change in wu,tpr- tnble elentt.ion at the ('11(1 of the growing SCUSOIl, the Ulllllllll !lnd average flIlnual net rise::; were drt.ermined for the seven wells, ,\ith the nctulll work being done 011 hydrogruphs of lnrgL'r scale_ The net rise thus determined represents depth of soil from which wuter was removcd by evupotruIl:-,pirntion. To conn-rt the Ilel ri~l' to depth of wllter, th(' net rise was multiplied by n ~atllratioIl index, which i~ upproximntely ('qual to porosity minus wilting \wrcpntugt'. RCllre- sentutin' suturntion indices were selt,(.!t'd and llpp ied to the portions of tlw saln\ge urell to which tllt'Y Wen' llPplicabh'. The nununl ,.olumes of eYnpotrnn~pirntion of gruund water within tilt' salvage afL'n during calrndnr years 1949 through 1957 llrp computed in htbles 4 /lnd 5_