Water levels in the Canisteo Legacy Mine Pit have dropped from 1,311 to 1,309.07 feet since the Minnesota Department of Natural Resources began contingency pumping last December.
“At this time last year, Canisteo water levels were 1.7 feet higher than they are right now,” said Mike Liljegren, assistant director for the DNR’s Lands and Minerals Division. “That means that over the last year, more water was pumped from Canisteo than the amount of water that went in naturally from groundwater, rain or snow melt.”
Winter contingency pumping was a water level management project to ensure that Canisteo’s water levels stayed below 1,318 feet. 1,318 feet is the water elevation at which the underground water pathway called a drain tile system can continue to operate and capture groundwater from the Canisteo and move water away from residential structures in the city of Bovey.
The DNR shut down water pumping activities on May 14, when the water temperature in the Canisteo increased to 48 degrees for four consecutive days. The decision to turn off the pumps was crucial to prevent the spread of zebra mussels, an invasive species. When water temperatures rise to 50 degrees or warmer, zebra mussels begin to reproduce. Immature zebra mussels called veligers, which are smaller and much more buoyant than a mature zebra mussel, have an easier time traveling through water. Turning off the pumps before zebra mussels reproduce helps ensure that veligers are not carried to downstream waters.
Looking ahead, the DNR is dedicated to continued monitoring, evaluation, and implementation of a permanent outlet structure to manage Canisteo water levels. The 2023 legislature approved $8.875 million dollars for construction of an outlet at the Canisteo to provide permanent and year-round water level management. The DNR is working on bidding out construction, which will include more dewatering of Canisteo. Construction of the outlet could potentially start in 2023.
Learn more about the Canisteo water management project and plans at the DNR website.