They are preparing for flooding.

The U.S. Army Corps of Engineers is lowering its reservoir elevations within the Red River Basin based on recent snow measurements in order to prepare for potential spring snowmelt, officials with the agency's St. Paul District said.
The Corps is currently lowering the elevation of Lake Ashtabula, located near Valley City, North Dakota. It will be drawn down nearly 2 feet in time for spring runoff, officials said.
Reservation Dam, part of the Lake Traverse project, near Wheaton, Minnesota, will be lowered by a foot and a half by the end of the month.
White Rock Dam, also part of the Lake Traverse project, and Red Lake Dam, near Red Lake, Minnesota, will not be lowered due to high inflows, the Corps said.