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OOG1H Accumulated reservoir inflow ranged from above normal to below normal throughout the year, One of the more critical areas was the North Platte River basin originating in southeastern Wyoming, Two basins that were near normal were the Cheyenne River basin in Wyoming and South Dakota and the South Platte River basin in northeastern Colorado, Reservoir storage was generaIly near normal in the tributaries to the upper Missouri River at the beginning of the 1990 water year and below normal on the tributaries to the lower Missouri River, By year's end on September 30, 1990, conditions were generaIly similar to the first of the year throughout the region, except in the Cheyenne and North Platte Rivers drainages in Wyoming, South Dakota, and Nebraska where conditions had degraded to weIl below normaL Project water delivery shortages were experienced during water year 1990 in the Beaverhead River basin in Montana, the North Platte and Wind River basins in Wyoming, the James River basin in South Dakota, and several smaller Reclamation projects in Nebraska and Kansas. Because of the drought'!l impact on the Beaverhead River basin's (Clark Canyon Reservoir) water supply, the irrigation season was discontinued approximately 6 weeks earlier than normaL Projected Conditions for 1991 Water deliveries for most projects in the Great Plains Region for 1991 should be adequate under most water supply scenarios, except for those projects that ended the year with low carryover storage, Expected conditions for two projects under dry conditions at the end of 1990 are discussed in the foIlowing paragraphs, BuIl Lake (Wind River Project) began the year with a content of 83,513 acre-feet (88 percent of normal), If 1991 inflows are near or above normal, BuU Lake would be expected to fill and have an adequate water supply for irrigation, However if lower decile inflows (equalled or exceeded 90 percent of the time) occur and a Wind River instream flow of 252 cubic feet per second is maintained, the reservoir wiU only fiU to about 100,000 acre-feet, or about two-thirds full. If that occurs, the water supply would not be adequate to meet aU irrigation needs, and the reservoir would be drafted to an unusually low level by the end of the year, Based on September 30, 1990, storage, Clark Canyon Reservoir in the Beaverhead River basin would be expected to fill to the top of the joint-use pool only under high runoff conditions, Reservoir storage would be expected to filI to 155,000 acre- feet, or about 23,000 acre-feet below the top of the joint-use pool-during a normal runoff year, Storage under normal runoff conditions would be adequate to satisfy irrigation demands during the 1991 irrigation season, Under low runoff conditions, storage would be expected to fiU to 130,000 acre-feet, or about 48,000 acre-feet below the top of the joint-use pooL Low runoff probably would result in shortage of irrigation water by the end of the 1991 irrigation season, 12