The Lake Byllesby Dam is located on the southern edge of Dakota County on the Cannon River. The county owns the dam and operates the powerhouse and water passage structures. Minnesota Department of Natural Resources regulates the water levels.
The Federal Regulatory Energy Commissioner gives the county an exemption to operate the turbines to produce electricity. The agency regulates power production and oversees dam safety requirements. The county sells energy produced on the open market.
In a year, the dam is expected to generate enough electricity to power about 4,000 homes.
Dakota County regulates the Lake Byllesby Reservoir and the Cannon River.
Read County Ordinance 128.
Dam history
The Lake Byllesby Dam was built in 1910. 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 was operated by Northern States Power until 1969 when it was sold to Dakota and Goodhue counties. Dakota County became sole owner in 2009.
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.
The dam is regulated as a high-hazard dam because of its size and location near Cannon Falls.