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:t r 1" .'-' (' ...:."" :.u IIY/JHOCR,IPIIY 65 ~ been detel'mined as about 2,:300,000 acre-feet annually after deduct- ing the estimated pumped overdraft on the region's ground-water storage. Due to the above normal rainfall and runoff of the 1952 irrigation season and the rapid and substantial increase in the irrigated acreage, particularly the enlarged cotton area ready for picking, the previously determined mean consumptive use in the Gila basin was probably considerably exceeded in 1952. Surface and pumped water records /Jot being as yet al'ailabJe here for the cur- rent year, however, and the overdraft not being determined defi- nitely as yet, the previous figure has ag-ain been accepted as a safe minimum. A combination of this approximate Gila ba:;in value, plus other tributaries as mentioned, with the records of table 14 indicate!-5 that present lower Colorado River basin diversiolls and ground water pumpage for basin pro.i~ct developments in 1952 involved the beneficial consumptive use of not Ie,s than 7,500,000 acre-feet annually, distributed by states as follows: J LnWI..1I H.~."'IN SH,n:s Cr)lrIIlADO RIVEn S':'TEM BIONU'IUAL CON<;L1YJPT!Vl: U~E ACIlE-FEET Arizona ............. California ............. Nevada.. . . " . . . . . .. . . New Mexico. . . . . . . . . . . . . Utah....... . . . . . . . . . . . . . . :3,100,000 . . . . . . . . . . . . . . .4,:300,000 45,000 30,000 45,000 Total ........... . . . . . . . . . . . . . . . . . . .7.520.000 -1 ---------- --- -- - ----- -- ~-- ------- The total l"e of about 7,500,000 acre-feet in 1952 represents 100 per cent of the Compact apportionment to the lower basin or, including the additional 1,000,000 acre-feet by which the lower basin is pel"mitted to increase its "firm" use, 88 per cent of the total available supply considered as firm under the Compact. This ratio is in contrast with a present upper basin use of 27 to :30 per cent, depending on whether the "depletion at Lee Ferry" or "diver- sions less returns to the river" interpretation of beneficial con- sumptive use is applied. The listed total for California is 80 per cent of the amount specified in contracts with the United States nearly 20 years ago of 5,362,000 acre-feet annually, which is con- sidered as permanently available when needed, b~' the terms of the Colorado River Compact. t ., ~