Water Storage in the Minnesota River Basin Water Storage Options Assessment: Report 1A

Climate change, land use change, surface and subsurface drainage, and other factors have resulted in a loss of surface storage and modification of subsurface storage in the Minnesota River Basin. Two goals have been set forth by the Minnesota River Sediment Strategy that are a 25 percent reduction in two-year peak flows and a 50 to 60 percent reduction in sediment loading. A previous process-based modeling study evaluated the benefits achieved with implementation of practices aimed at reducing sediment erosion and loading. Under high adoption rates of complementary co-implemented practices, the results indicated a 10 percent reduction in two-year peak flow and 25 percent reduction in upland sediment loading (Tetra Tech 2019). While these practices can support progress towards accomplishing the goals of the Minnesota River Strategy, additional water storage practices are needed to achieve larger reductions in flow and associated near-channel erosion. This report describes 10 key water storage practices and summarizes important information about each practice related to site and landscape suitability, storage effectiveness, storage volume variability, co-benefits, unintended consequences, limitations, and costs and practical information.