Updated: Aug. 14, 2025

VILLAGE OF MERTON, Wis. (CBS 58) -- In parts of Waukesha County, rising water pushed the Merton Millpond Dam to the brink of failure. 

DNR crews responded and have since stabilized the situation but on Thursday, a new concern is emerging. 

Village officials say a small sinkhole appeared behind the south spillway wall Monday afternoon. The sinkhole has since expanded. 

Village President Ron Reinowski says it's stabilized for the moment, but a level two emergency has been declared. That status does not mean a dam failure is imminent. Instead, this allows the village to work directly with Waukesha County Emergency Operations, the DNR, and the state. 

Crews will install a temporary fence and the adjacent parking lot will stay closed until engineers confirm the ground underneath is safe. 

Officials are also reminding people to stay away from fast-moving water. 

Published: Aug. 12, 2025

VILLAGE OF MERTON, Wis. (CBS 58) -- The Merton Millpond Dam is at a level two emergency state, according to local law enforcement, indicating a "high potential for failure."

Village of Hartland police say the dam has not been breached at this time, and the Wisconsin DNR is confident they will be able to reinforce it -- however, residents and businesses along the Bark River are cautioned to be aware of the potential rise in water levels. 

The Village of Merton says there has been "significant erosion" and engineers and local authorities are on scene evaluating.

Police say the Bark River water level could rise within the 100 to 500-year floodplain.

Residents in the area should continue to monitor water levels -- you can see if you're in the floodplain by clicking here.