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Show A48 APPENDIX 206 Question 4- If the maximum quantity of water is diverted for irrigation in the upper basin, how much of it will return to the river by seepage and drainage and be available for use at Lee Ferry? Answer 4. Above figures are based upon an average figure for "consumptive use"; that is, diversion minus return flow, and are believed to be large enough to include evaporation from local reservoirs which will be used for irrigation. They therefore represent the net reduction in the flow of the river to be anticipated under the assumed conditions. Question 5. After deducting the maximum quantity of water that may be diverted out of the upper basin and the maximum amount that may be consumed by irrigation and domestic uses, what is your estimate oi the average annual run-off from the upper basin in acre-feet at Lee Ferry? Answer 5.- Acre-feet Mean discharge at Lee Ferry, 1903-1920 (assumed same as Laguna)_ 16, 400, 000 Past depletion, upper basin, 1,094,000 acres (average) at 1.54 acre-feet per acre__________________________________________ 1, 700, 000 Reconstructed river at Lee Ferry______________________ 18, 100, 000 Upper basin: Maximum consumption______________________ 6, 150, 000 Diversion out of basin_______________________ 444, 000 ------------- 6, 590, 000 Remaining flow at Lee Ferry_________________________ 11, 510, 000 Question 6. If the same maximum deductions are made from the quantity of water in the Colorado River when that stream had the least recorded annual flow, how many acre-feet would remain for use in the lower basin? Answer 6. The above maximum deductions could not be made when the Colorado had its least recorded annual flow because sufficient water would not be available in the tributaries for maximum diversion. Assuming that the consumptive use would be reduced 25 percent during this shortest year, and taking the flow at Lee Ferry, the same as that at Laguna, as given on page 5 of Senate Document 142, we have- Acre-feet Discharge at Lee Ferry, 1902_______________________________ 9, 110, 000 Depletion, 1902 (665,000 acres at 1.54), by 75 per cent___________ 770, 000 Reconstructed river at Lee Ferry, 1902__________________ 9, 880, 000 Maximum consumption, upper basin, 1902 (75 per cent of 6,590,000)_ 4, 940, 000 Available at Lee Ferry, 1902__________________________ 4, 940, 000 This indicates that under the compact the flow of the lowest year would be available in approximately equal portions for the use of each basin. |
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Original book: [State of Arizona, complainant v. State of California, Palo Verde Irrigation District, Coachella Valley County Water District, Metropolitan Water District of Southern California, City of Los Angeles, California, City of San Diego, California, and County of San Diego, California, defendants, United States of America, State of Nevada, State of New Mexico, State of Utah, interveners] : |