Upper Missouri Basin
September precipitation across the Upper Missouri Basin was below average. Basin precipitation summaries for the Missouri Basin include: Milk St. Mary, 42 percent; Milk Canada, 23 percent; Lower Milk, 15 percent; above Toston, 25 percent; Toston to Ft. Peck, 14 percent.
Of the four major irrigation reservoirs in Montana; Lima Reservoir had 73 percent average storage, Clark Canyon was holding 73 percent of average water, Gibson Reservoir had 51 percent of average stored water, and Fresno Reservoir had 84 percent of average stored water.
Yellowstone Basin
Precipitation during September was below average. The upper Yellowstone River Basin received 23 percent of average precipitation while the Lower Yellowstone River Basin reported 31 percent of average. The Bighorn Basin received 23 percent of average precipitation while the Wind River Basin received 49 percent of average. The Little Bighorn - Upper Tongue Basin received 26 percent of average and the Powder River had 38 percent of average precipitation.
Monthend storage at Boysen Reservoir was 101 percent of average. Stored water in Buffalo Bill Reservoir was 89 percent of average. Monthend storage was 88 percent of average at Bighorn Reservoir.
Platte Basin
Precipitation during September in the Upper North Platte Basin was 102 percent of average. In the Lower North Platte Basin, precipitation was 84 percent of average. The North Platte Plains below Guernsy Reservoir had 29 percent. The South Platte Mountains had 55 percent whereas the Plains had 65 percent of average September precipitation.
Stored water in the South Platte Basin was 120 percent of average on October 1.
