By 1974, however, within ten brief years, there may not be 7.5 million acre-feet per annum available for consumptive use in the Colorado River below Lee Ferry to divide among the Lower Basin States. In succeeding years the amount of water for division will steadily decrease as the Upper Basin States put to use their apportioned waters in accordance with the Upper Basin Compact. Ultimately, the 7.5 million acre-feet could be reduced by 2.0 million acre-feet per year or more. This is only a part of the water shortage facing the Pacific Southwest. By the year 2000 it is estimated that new water supplies of about 4.0 million acre-feet must be developed over and above existing supplies and additional supplies to be developed by works now under c...