Upper Missouri Basin
August precipitation across the Upper Missouri Basin was near to below average. Basin precipitation summaries for the Missouri Basin include: Milk St. Mary, 11 percent; Milk Canada, 25 percent; Lower Milk, 23 percent; above Toston, 39 percent; Toston to Ft. Peck, 34 percent.
Of the four major irrigation reservoirs in Montana; Lima Reservoir had 141 percent average storage, Clark Canyon was holding 105 percent of average water, Gibson Reservoir had 131 percent of average stored water, and Fresno Reservoir had 48 percent of average stored water.
The major hydroelectric reservoirs in Montana (Canyon Ferry and Fort Peck), had monthend storage in the average to above average range; 99 and 117 percent of average water, respectively.
Yellowstone Basin
Precipitation during August was near average. The upper Yellowstone River Basin received 60 percent of average precipitation while the Lower Yellowstone River Basin reported 70 percent of average. The Bighorn Basin received 53 percent of average precipitation while the Wind River Basin received 13 percent of average. The Little Bighorn - Upper Tongue Basin received 58 percent of average and the Powder River had 45 percent of average precipitation.
Monthend storage at Boysen Reservoir was 97 percent of average. Stored water in Buffalo Bill Reservoir was 123 percent of average. Monthend storage was 100 percent of average at Bighorn Reservoir.
Platte Basin
Precipitation during August in the Upper North Platte Basin was 35 percent of average. In the Lower North Platte Basin, precipitation was 35 percent of average. The North Platte Plains below Guernsy Reservoir had 20 percent. The South Platte Mountains had 29 percent whereas the Plains had 41 percent of average August precipitation.
Stored water in the South Platte Basin was 95 percent of average on September 1.
