Impacts of a Lake Bronson Dam Break on the Cities of Lake Bronson and Hallock, Minnesota

The Lake Bronson Dam is a high-hazard1 dam located in Lake Bronson State Park, near the city of Lake Bronson in Kittson County, Minnesota. Issues associated with the Lake Bronson Dam include the potential for major flooding, including personal injury and loss of life in the cities of Lake Bronson and Hallock, if the Lake Bronson Dam should fail. Specific concerns are areas adjacent to the river between the dam and the city of Lake Bronson, Kittson County State Aid Highway 28 over the Lake Bronson Dam, and several houses in the city of Lake Bronson. In the city of Hallock, specific areas of concern include the city park and campground at the Hallock Dam, and several residences along the river. There is also concern about the possible overtopping of levees between Minnesota Highway 175 and US Highway 75. Using the U.S. Army Corps of Engineers computer program HEC-RAS (Hydrologic Engineering Center- River Analysis System), a computer model was created for a 38-mile length of the South Fork Two River between US Highway 75 in Hallock, Minnesota, and a cross-section located approximately three miles northeast of the Lake Bronson Dam. The computer model was used to calculate potential water surface elevations in the cities, and to delineate areas subject to flooding as a result of a dam break.