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Show Water Supply for the Lower River: 1. Delivery at Lee Ferry 8.250 maf 2. Net Inflow Lee Ferry to Lake Mead 0.675 3. Net Inflow from Bill Williams River 0.055 4. Release from Lake Mead (drawdown to rated power head) 0.365 Total Water Supply 9.345 Deficiency 1.195 maf Although an arbitrary initial delivery of 8.25 maf has been assumed in some of the studies, the amount delivered by the Upper Basin eventually will approximate 7.5 maf per year. When the delivery from the Upper Basin is 7.5 maf instead of 8.25 maf, then the deficiency will be 1.945 maf per year. If the provisions of Section (b) of Article IV of the Colorado River Compact are invoked, Lake Mead could be drawn down to absolute dead storage which would provide about 0.60 maf additional water per year which includes the decrease in evaporation from Lake Mead. In this case the above deficiencies would be reduced by about 0.60 maf. "The obvious conclusion is that a firm water supply is not available in the Colorado River to satisfy a basic beneficial consumptive-use requirement of 7.5 maf from the main stem by Arizona, California and Nevada, plus delivery of 1.5 maf of water to Mexico. If these requirements as well as Upper Basin requirements are to be satisfied, projects must be authorized and constructed to import major amounts of water into the Colorado River Basin from sources of surplus. Such importation is important to both the Upper and Lower Basins." "Conclusions "Upper Basin "If it is assumed that the operating capacity of the Upper Colorado River Storage Project is 29.0 maf, and if the delivery at Lee Ferry amounted to 7.5 maf per year, the depletions (beneficial consumptive use) in the States of the upper division of the Colorado River Basin would be limited to 6.3 maf per annum. The net depletion, excluding evaporation from the reservoirs of the Upper Colorado River Storage Project, would be 5.6 maf. If deliveries at Lee Ferry were 8.25 maf per year, the limit of depletions in the States of the upper division would be 5.6 maf including reservoir evaporation, and a net of 4.7 maf excluding reservoir evaporation. 33 |