The Whetstone River is a tributary of the Minnesota River, approximately 35 miles long, beginning in the Coteau des Prairies region in South Dakota. Historically the Whetstone River flowed into the Minnesota River just south of Ortonville. The river was diverted into Big Stone Lake in the 1930’s to increase Big Stone Lake levels during times of drought. The Whetstone River currently flows into Big Stone Lake, just upstream from the Big Stone Lake Dam.
In recent years, high flows have caused flooding in Big Stone Lake, with the Whetstone River contributing a substantive amount of water. The Upper Minnesota River Watershed District (UMRWD) plans to restore ecological services by reestablishing continual flow to an estimated 9,000 feet of open channel known as the Whetstone River Restoration Project. 
The UMRWD’s proposed Whetstone River Restoration Project is located in the abandoned historic Whetstone River channel south of Ortonville. This historic channel was abandoned after the1930’s diversion and currently only has flows from adjacent land.
The Whetstone River Restoration will hydrologically and ecologically reconnect a portion of the Whetstone River to the Minnesota River.
By default, this will improve conditions within Big Stone Lake reducing nutrient loads, improving water quality and reducing flooding.
In addition the project will restore floodplain wetlands for additional flood storage, duck and wildlife habitat, as well as restore a wildlife corridor allowing fish passage upstream.
The engineering, design and land purchase phase is on schedule to be completed by the end of 2022.Construction will be scheduled in multiple phases with a goal completion date of December 2027