In this chapter:
(1) “Emergency” means a condition or circumstance in which a person reasonably believes that an individual has sustained serious bodily injury or is in imminent danger of serious bodily injury or that property has sustained significant damage or destruction or is in imminent danger of significant damage or destruction.
(2) “Motor vehicle” means any wheeled or tracked vehicle, machine, tractor, trailer, or semitrailer propelled or drawn by mechanical power and used to transport a person or thing.
(3) “Navigable river or stream” means a river or stream that retains an average width of 30 or more feet from the mouth or confluence up.
(4) “Protected freshwater area” means that portion of the bed, bottom, or bank of any navigable river or stream that lies at or below the gradient boundary of the river or stream. The term does not include that portion of a bed, bottom, or bank that lies below tidewater limits.