The Coast Guard is establishing a temporary safety zone for navigable waters of the St. Clair River in the vicinity of Port Huron, MI. This zone is intended to restrict and control movement of vessels in a portion of the St. Clair River. Though this is an unsanctioned, non-permitted marine event, this zone is necessary to provide for the safety of life on the navigable waters during a float down event near Port Huron, MI.
Source: Federal Register USCG
Link: Safety Zone; Port Huron Float Down, St. Clair River, Port Huron, MI