Wis. Stat. § 87.085: Federal cooperation.

Any public corporation or flood control board acting under its powers and in conformity with state law may enter into an agreement with an agency of the federal government to cooperate in the construction, operation or maintenance of any federally authorized project contemplated under this chapter or to assume any potential liability appurtenant to such project and may do all things necessary to consummate the agreement. Such public corporation or flood control board may jointly or separately enter into such an agreement with an agency of the federal government carrying such terms and provisions concerning the division of costs and responsibilities as may be mutually agreed upon.