As warmer weather moves into the Missouri River Basin, spring precipitation brought some much-needed moisture throughout the basin. For the month of April, runoff was 2.1 million acre-feet, 71% of average, for the basin above Sioux City, Iowa.
“While the calendar year forecast remains below average, the runoff forecast continues to improve thanks to higher-than-expected rainfall in April,” said John Remus, chief of the U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division. “We hope to see the precipitation trend continue to provide the much needed moisture for the region.”
The annual runoff forecast for the upper Missouri River Basin above Sioux City is 19.2 MAF, 75% of average, and 1.7 MAF higher...
The graphic on the left is the snow water equivalent map showing the remaining mountain snowpack which is peaked at 73% of normal on April 9 and has 88% of the peak remaining as of May 1 in the Fort Peck reach and the Garrison reach peaked at 82% of normal on April 10 with 89% of the peak remaining as of May 1. The graphic on the right shows the rainfall observed in the Missouri River Basin for the previous 30 days. Eastern Montana saw the least amount of rain while areas downstream of the Mainstem system saw an average of 4-5 inches of precipitation in northeast Nebraska and much of Missouri saw between 6-10 inchs of rain. The May forecast for upper basin runoff is 19.2 million acre feet.
B-roll by Amber Tilton of spill operations at John Day Dam, March 28, 2024 After an agreement to stay the Columbia River Basin litigation for up to 10 years, federal water managers will begin spilling more water over basin dams this spring than in past years. This year, four projects on the lower Snake River and McNary Dam on the Columbia River will also begin spilling four hours each day through surface passage routes to primarily assist migrating adult steelhead starting March 1. Beginning March 21, those projects, plus John Day Dam on the Columbia River, will begin spilling through surface passage routes 24 hours each day until regular spring spill begins with the goal of providing additional benefits for both juvenile and adult...
