Mississippi River Headwaters reservoir drawdowns nearly complete
1 / 2 Show Caption + Hide Caption – Brian Turner, U.S. Army Corps of Engineers, Gull Lake Dam and Recreation Area site manager, adjusts the dam gates at Gull Lake Dam, near Brainerd, Minnesota, Dec. 21, 2021. (Photo Credit: Patrick Moes) VIEW ORIGINAL
Mississippi River Headwaters reservoir drawdowns nearly complete
2 / 2 Show Caption + Hide Caption – Shawn Weissenfluh, U.S. Army Corps of Engineers, St. Paul District natural resources specialist, conducts a snow survey at Leech Lake Recreation Area near Federal Dam, Minnesota, Dec. 21, 2021. (Photo Credit: Patrick Moes) VIEW ORIGINAL

The Corps of Engineers water managers, along with park rangers at each of the six reservoirs in northern Minnesota, are collaboratively working to make necessary water level adjustments ahead of the spring snowmelt.

Jim Noren, St. Paul District hydrologist in charge of the headwaters reservoirs water levels, said the primary goal is lowering the reservoir levels to gain storage capacity by March 1. He said the team can make necessary adjustments, if needed, after that but the initial goal is to reach the target levels before the flood threat. The Corps’ headwaters reservoirs include Leech Lake, near Federal Dam, Minnesota; Lake Winnibigoshish, near Deer River, Minnesota; Pokegama Lake, near Grand Rapids, Minnesota; Big Sandy Lake, near McGregor, Minnesota; Cross Lake, near Crosslake, Minnesota; and Gull Lake, near Brainerd, Minnesota.

Noren said the drawdowns are all about coordination among the Corps of Engineers’ water management engineers, park rangers, survey technicians, as well as partner organizations such as the National Weather Service and Minnesota Department of Natural Resources. “Communication is key to getting the reservoirs drawn down to the right levels based on current conditions,” Noren said. “All the stakeholders bring valuable information to the decision process and help make the process as smooth as possible.”

For Brian Turner, Gull Lake Dam and Recreation Area site manager, the winter snow surveys are a way of gathering information about the amount of snow, and more importantly, the amount of water contained within the snowpack. Turner said the information, known as snow water equivalent, or SWE, is then shared with Noren and others in a coordinated effort to manage the reservoir system in minimize flood threats to the region.

The surveys are simple, Turner said. With a nearly 3-foot silver tube around 2 inches in diameter, he pushes the tube into the snow until he reaches the ground. After a quick scraping of the soil, the snow is then pushed into a container where it is weighed to determine the SWE. He said they usually take around three samples and average them to get an indication of the amount of moisture in each area. Turner said he and the park rangers at the other sites routinely collect the information.

Once he receives the information from all the sites within the headwaters, Noren said he reviews it and makes necessary adjustments in accordance with the operational plan for the system. “It’s critical to evaluate the possible consequences any gate movement at a dam has for each reservoir, but also the reservoirs and municipalities downstream, such as Aitkin, Minnesota, Noren said.

Noren added that the reservoir levels are in good shape at this point in the season, and the team is coordinating directly with partner agencies ahead of the snowmelt to ensure everyone is prepared to do what they can to reduce flood risk.

“At this time, the watershed’s snow and frost conditions indicates an average spring melt for the Headwaters of the Mississippi River,” Noren said. “However, we must stay watchful because the timing and magnitude of the runoff can dramatically change based on the weather conditions we see in the next few months.”