Section R. 560.301 - DefinitionsRule 301. As used in this part:
(a) "A 100-year flood" means a flood with a magnitude which has a 1% chance of occurring or being exceeded in any given year.(b) "Datum" means the basis from which elevations are measured.(c) "Flood" means a temporary increase in the stage of a watercourse or lake resulting in the inundation of lands not normally covered by water.(d) "Floodplain" means that area of land adjoining a watercourse or lake which will be inundated by a 100-year flood.(e) "Lake" means a natural or artificial body of water with a surface area of 5 acres or more measured at its normal stage, including the great lakes.(f) "Watercourse" means an open conduit either naturally or artificially created which periodically or continuously contains moving water draining an area of not less than 2 square miles. The point of measurement of the drainage area shall be the downstream limit of the subdivision.Mich. Admin. Code R. 560.301