Dams are an important part of the infrastructure of Minnesota. They maintain lake levels and impound water for flood control, power production and water supply.
There are more than 1,150 dams in Minnesota; 650 are public dams, and the state owns over 300 of the public dams. Most of the public dams are more than 50 years old and require ongoing or emergency repairs and reconstruction to maintain their structural integrity. Through state bonding, the DNR spends approximately $2 million annually on repairs and reconstruction. An estimated $103 million is needed over the next 20 years to assure public dams remain in a safe and usable condition.
Dam failures are typically due to poor maintenance, inadequate design, unusually large floods, or improper operation.
Dam Safety Permits
Permits are required to build a new dam; alter, repair, or remove an existing dam; modify dam operations; perform major maintenance; or transfer dam ownership. Plans for construction must be completed by a professional engineer experienced in dam engineering. Application and inspection fees may apply.
Dam Owner Responsibility
Dam owners must properly maintain, repair, and operate their dams. They may also be required to make improvements to meet current dam safety criteria. If development downstream raises the hazard classification of the dam, the owner may be required to bring the dam into compliance with the higher standards required under the new classification. The owner of the dam could be found liable for damages incurred from dam failure or improper operation, particularly if the dam is not compliant with state standards. The DNR repairs and maintains state-owned dams.
Construction and operation of a dam can have varied impacts to surrounding lands and the environment. Losses suffered by other parties can become liabilities to a dam owner. Impacts could include:
- altered ground water levels that affect wells or crops
- increased flooding caused by improper operation
- injuries to anglers, boaters or swimmers because of hazardous conditions at the dam
- environmental damages including degraded water quality, alteration of sediment transport, increased erosion, loss of aquatic habitat, and altered stream biology.
Find a dam
The DNR maintains data on Minnesota dams including the dam name, location, owner, purpose, hazard classification, structural condition, and about 80 additional data elements. Dam Finder is a simple mapping application that provides basic information on each dam in the DNR database. Information on Minnesota dams included in the National Inventory of Dams (NID) database is available online in the national mapping application. The GIS link allows the user to download a geodatabase or shapefile of dams in Minnesota.
- Lake Outlet Dams
- The Drowning Machine
- FEMA Dam Safety Information
- Association of State Dam Safety Officials