Warm temperatures in the mountainous region of the upper Missouri River Basin has led to a quick melt of the mountain snowpack. The rapid melting combined with precipitation in the western half of the Basin resulted in above-average inflow into the reservoir system. May runoff for the Basin above Sioux City, Iowa, was 4.9 million acre-feet, 144 percent of average.
John Reemus of the U.S. Army Corps of Engineers says, “With much of the mountain snowpack already melted, the basin will need additional rainfall to continue the trend of above-average runoff.” The annual runoff forecast above Sioux City, Iowa, is 26.8 million acre-feet, 104 percent of average. While portions of the Basin received above-normal rainfall, precipitation was below normal during May.
Gavins Point Dam releases will provide minimum-service navigation flow support at all four target locations of Sioux City, Omaha, Nebraska City, and Kansas City through the first half of the navigation season which ends on July 1.
