2019 Upper Missouri Basin—Runoff, Reservoir Regulation, and Monitoring Network

The Missouri River Basin endured major flooding in 2019, starting with the March 13-14 “bomb cyclone” that resulted in major flooding in Nebraska and Iowa. Over the spring and summer, flooding expanded in the basin to include South Dakota, Kansas and Missouri. The U.S. Army Corps of Engineers’ (Corps) regulation of the Missouri River Mainstem Reservoir System (System) was heavily scrutinized during 2019. The Corps’ mission, as it applies to the System, is to serve eight Congressionally authorized purposes: flood control, navigation, irrigation, water supply, water quality, hydropower, recreation and fish and wildlife. The 2019 runoff in the Upper Missouri Basin (UMB), which is the 315,000 square miles upstream of Sioux City, Iowa, is expected to exceed 50 million acre-feet (MAF). If realized, the 2019 UMB runoff would be the second highest runoff in 121 years of record-keeping (1898-2018), exceeded only in 2011 (61.0 MAF). After the record 2011 event and as part of one of the recommendations from the Independent Review Team that assessed the regulation of the System during 2011, the Corps initiated the formation of the Upper Missouri Basin Monitoring Network for Soil Moisture and Plains Snow (UMB MN). The plains area of the UMB is approximately 270,000 square miles. The UMB MN plan, which consisted of a generalized framework of sites and equipment, was authorized, but not funded, by Congress in 2014 via the Water Resources and Reform Development Act (2014 WRRDA). Because funding was not available, no action was taken to implement the UMB MN. After 2018, which is currently the third highest runoff in 121 years of record-keeping (42.1 MAF), basin-wide interest in the UMB MN increased. Funds are currently available for the Corps to update the UMB MN plan to include detailed locations for 500-600 sites, purchase and install equipment, and initiate discussions with partner agencies regarding roles and responsibilities. Efforts are now underway to identify existing networks (e.g., SD Mesonet, MT AgriMet, NDAWN) that can be upgraded to be part of the UMB MN as well as identify locations for new stations.