The Lake Byllesby Dam is located on the southern edge of Dakota County. The dam is owned by Dakota County and regulated by the Federal Energy Regulatory Commission and the Minnesota Department of Natural Resources.
Dakota County contracts with a vendor to operate the turbines that produce electricity. The operator then sells the energy produced by the dam to Xcel Energy.
In a year, Lake Byllesby Dam generates enough electricity to power about 2,400 homes.
The Lake Byllesby Dam was built in 1910 when Henry M. Byllesby & Company constructed it across the Cannon River on the border of Dakota and Goodhue counties. Using mostly hand labor, a crew of 500–600 began work in April 1910 and completed the work in just nine months.
The dam created the Lake Byllesby Reservoir, a 3.5–mile long, 1,432–acre lake.
The concrete dam is more than 1,100–feet long and more than 60–feet high from its base with nearly 400 feet of spillway. The crest of the spillway is 854 feet above sea level.
Repairs and safety improvements
Dakota County completed numerous large-scale projects to improve the safety and operations of the Byllesby Dam.
The process started in 2007 with a letter from the Federal Energy Regulatory Commission (FERC) requiring Dakota County to increase the capacity of the Byllesby Dam from 40,000 cubic feet per second (cfs) to 80,800 cfs which is 100 percent of the Probable Maximum Flood, the most severe possible flood calculated by combining information about precipitation, geology and water management strategies.
To meet this requirement, Dakota County upgraded the Byllesby Dam with two new 65-feet wide by 14-feet tall hydraulically operated crest gates to provide flood control. The total project cost $7.5 million, one half was provided by Minnesota Department of Natural Resources Dam Safety Grant Funds.
In 2015-2016, Dakota County completed repairs to the existing dam structure. Improvements included:
- Large scale bedrock repairs
- Repairing the existing concrete face of the dam
- Adding piers and a bridge over the overflow structure
- Repairing the existing gate systems on the top of the dam
For more information, contact Josh Petersen at firstname.lastname@example.org or 952-891-7140