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Lake Byllesby spring refill planned
The annual refill of Lake Byllesby reservoir to the summer elevation is planned to begin on Thursday, May 15 or as soon after river flow conditions will allow.
In the fall, the reservoir level is lowered three feet to 853.7 feet, and remains there until May 15 when refilling to the summer elevation of 856.7 feet is permitted to start. The Minnesota Department of Natural Resources (DNR) sets these levels, and according to a study, the winter drawdown lowers adjacent groundwater levels, which accommodates local agricultural needs.
Refill is accomplished by raising 41 trip gates located at the top of the spillway to an upright position, and then, using turbine and crest gate capabilities, up to 20 percent of the incoming flow of the Cannon River to the reservoir is captured to fill the pool. The remaining 80 percent of inflow must be conveyed downstream through the turbines and crest gates. The DNR permit further states that if Cannon River flows drop below 50 percent of the mean annual flow as measured at Welch, no appropriation of inflow to the reservoir will be captured until flows increase.
Raising the trip gates requires employees of the Dakota County Parks Department to access the top of the spillway to manually lift and set the gates. This is safely possible only when there is little to no flow over the spillway. In the event that it is not possible to raise the gates on May 15, the gates will be raised at the earliest possible date thereafter.
For current information about the refill process, call the Dakota County Parks Department at 952-891-7000. |
This page was last updated on: 05/05/2008
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