2025 Wisconsin Statutes & Annotations
Chapter 30 - Navigable waters, harbors and navigation.
30.15 - Penalty for unlawful obstruction of navigable waters.

30.15 Penalty for unlawful obstruction of navigable waters.

(1) Obstructions penalized. Any person who does any of the following shall forfeit not less than $10 nor more than $500 for each offense:

(a) Unlawfully obstructs any navigable waters and thereby impairs the free navigation thereof.

(b) Unlawfully places in navigable waters or in any tributary thereof any substance that may float into and obstruct any such waters or impede their free navigation.

(c) Constructs or maintains in navigable waters, or aids in the construction or maintenance therein, of any boom not authorized by law.

(d) Constructs or places any structure or deposits any material in navigable waters in violation of s. 30.12 or 30.13.

(3) Each day a separate violation. Each day during which an obstruction, deposit or structure exists in violation of sub. (1) is a separate offense.

History: 1987 a. 374.

Municipalities have the power to construct bridges but are not authorized to construct or maintain bridges that constitute an unnecessary obstruction or hazard to the free use of navigable waters. A bridge undoubtedly is an obstruction. The question becomes is the obstruction unnecessary or unreasonable under the circumstances. When the bridge was necessary, reasonable, and existing before the plaintiff moved into the area, the city was not required to abate the obstruction. Capt. Soma Boat Line, Inc. v. City of Wisconsin Dells, 79 Wis. 2d 10, 255 N.W.2d 441 (1977).

If an unattended and anchored boat is left on navigable water for an unreasonable length of time, it constitutes a violation. 63 Atty. Gen. 601.