The Twin Cities experienced record snowfall in late winter 2019. With cold temperatures helping to maintain the snowpack, Barr regularly estimated the snowpack’s water equivalent to determine if and when the Valley Branch Watershed District should implement emergency drawdown procedures for its flood-prone lakes in the northwest portion of the watershed. Six outlets on the lakes and other water bodies include adjustable weirs so that the district can lower lake levels under certain conditions.
In mid-March, Barr measured an average of four inches of water equivalent in the snowpack, triggering emergency drawdown procedures. We notified property owners and coordinated with the Minnesota Department of Natural Resources to gain access to the outlets. With Barr’s direction, the district’s contractor then began removing stop logs, monitoring water elevations, and replacing stop logs at all six outlets and associated water bodies. We provided construction oversight and continued to monitor the snowpack’s water equivalent.
During the 12-day emergency drawdown, the district created an additional storage volume of nearly 600 acre-feet in the water bodies by lowering the outlets—enabling the system to store and convey snowmelt and rain runoff with a reduced flood risk to adjacent property owners. While flooding affected infrastructure and homes in other Twin Cities areas, no significant flooding or damage to homes occurred around the Valley Branch Watershed District’s flood control system.