Major construction at the former Willow River dam site is expected to wind down for the season by the end of February, according to the Minnesota Department of Natural Resources.
A temporary diversion created to dewater the work area will be removed during the week of Feb. 15, and water will resume flowing in the original river channel. At current flow, the water level in the Stanton Lake reservoir is expected to refill in a matter of days to its pre-breach level.
Snowmobilers, ice anglers and other recreationists are asked to avoid going out onto the ice on Stanton Lake and below the rock arch rapids as the fluctuating water levels could create unsafe ice conditions. Flowing water can erode existing ice, and as the reservoir refills, fluctuating water levels could also create new layers of thin ice.
Warning signs about the changing ice conditions have been posted at common access points.
“The water level will be restored to its historic elevation, but the dam site looks very different without the massive concrete structure there,” said Jason Boyle, state dam safety engineer with the DNR.
Additional construction will take place in the spring to adjust rock placements as needed. A trail along the rock rapids will be created and vegetation will be planted. The rock arch rapids will restore passage for fish, mussels and other aquatic life that the former dam blocked, and will eliminate the drowning hazard associated with the previous dam structure.
The dam, built in the 1940s, breached in July 2016 after a large flood overtopped the dam and eroded the adjacent embankment. The dam removal and rock arch rapids construction is a $1.8 million project funded by capital bonding dollars appropriated in 2017 by the Minnesota Legislature.