Mich. Comp. Laws § 247.659d

Sec. 9d. As used in this act, "port facility" means a commercial facility located alongside a navigable waterway used for commercial vessels and includes any of the following types of facilities: (a) A seawall jetty, pier, wharf, or dock. (b) A warehouse, storehouse, elevator, grain bin, cold storage plant, terminal icing plant, bunker, or oil tank. (c) A ferry, canal, lock, seaway, or conveyor. (d) A modern appliance for the economical handling, storage, or transportation of freight and handling of passenger traffic. (e) A transfer or terminal facility required for the efficient operation or development of a port or harbor. (f) Any other port or harbor improvement to assist with commercial operations. (g) An improvement, enlargement, remodeling, or extension of a facility described in this section.