Wis. Stat. § 31.187: Abandoned dams.

(1) The department may remove or cause to be removed, in such manner as it deems fit, old and abandoned dams in streams in this state, upon giving 60 days’ notice in writing to the owner thereof, if the owner can be found. If the owner of the dam is unknown or cannot, by due diligence, be found, the department shall publish a class 3 notice, under ch. 985, in the county in which the dam is situated.

(2) Whenever the department determines that the conservation of any species or variety of wild animals will be promoted thereby, the department may maintain and repair any dam located wholly upon lands the title to which is in the state either as proprietor or in trust for the people after giving due consideration to fixing the level and regulating the flow of the public waters.