WSPC12808 - Laserfiche WebLink

Home Browse Search

..~ e e B. Colorado River Water Supply 1. Reclamation's natural flow data base 1906-1978 was used as the unenhanced water supply. 2. The CREST Planning Study considered three alternatives: a. Alternative 1 - Base (no enhancement). b. Alternative 2 - Upper Basin scenario. c. Alternative 3 - Lower Basin scenario. Alternatives 2 and 3 included enhanced hydrology 1S described in section C (below). The difference between alter" tives 2 and 3 was in the assumed operating rules as described in section II.B (below). 3. Initial conditions shall be those predicted for September 30, 1982, resulting from the current year's spring runoff. 4. Long-range operations will be projected from water year 1983 thrcugh 2072, a 90-year period. c. Weather Modification (Enhanced Stream Flow) Conditions 1. The 5-year demonstration program is projected to be in operation during water years 1986 through 1990 producing 340,000 acre-feet annually of flow augmentation. 2. The operational weather modification program is projected to be in full operation beginning in water year 1991 and continue, thereafter, producing about a 10 percent increase in water supply. 3. The enhanced hydrology did not take into account any suspension criteria. That is, in alternatives 2 and 3, augmentation occurred regardless of the magnitude of the runoff in any particular year. 4. In alternatives 2 and 3, depletions in the Upper Basin are assumed to develop from 5.8 maf to 6.3 maf over the future years 2040 through 2070. II. Criteria Assumed for Long-Range Operations A. Upper Basin 602(a) storage requirement will be assumed as the currently used rule curve based upon the most critical 34-year water supply period 1931 through 1964. B. Releases from Glen Canyon Dam 1. The base condition or alternative 1 will assume an objective release of 8.23 maf from Glen Canyon Powerplant.