I used fish there occasionally and remember the sign at the beach. If they do own that dam or not if the police were called what ever they say be polite and follow there request. Not worth a bookem Danno Samario. If you don't own it or know for a fact who does and gives you permission or permission outlined in general statute your in the wrong.

St. Clair River. Port Huron, MI.
#1 Prolific Fishery in North America Bar None!