Dakota County upgraded the Byllesby Dam with two new 65-feet wide by 14-feet tall hydraulically operated crest gates to provide flood control. This project was required by the Federal Energy Regulatory Commission to meet standards for 100 percent of the Probable Maximum Flood, the most severe possible flood calculated by combining information about precipitation, geology and water management strategies.
Scheduled future improvements
Existing facility improvements
From now until spring 2016, Dakota County will be completing some repairs to the existing dam structure. Improvements include repairing some bedrock, repairing the existing concrete face of the dam, adding piers and a bridge over the overflow structure, and repairing the existing gate and intake systems.
A dry condition on the upstream face of the dam is necessary for some repairs, requiring a temporary drawdown. The temporary drawdown has been coordinated and scheduled with the Minnesota Department of Natural Resources. All work is expected to be completed during winter 2016 with no effect on summer 2016 lake level operations.
Turbine and powerhouse upgrades
The turbines inside the dam are approximately 102 years old. They have had several major overhauls over the years and are reaching the end of their service life. Combined with an aging powerhouse structure, it has been determined that an upgrade will be required. Dakota County is currently in the preliminary design and concept phases for this project. More information will be provided as the County enters into the design phase in the coming years.