36.15.502    FLOODWAY DELINEATION

(1) The delineations of a designated floodway shall be based on the channel of the water course or drainway and those portions of the adjoining floodplain which are reasonably required to carry the discharge of the base flood without cumulatively increasing the water surface more than one half foot.

(2) In areas having appreciable urban development on the floodplain, the outer boundary lines of the floodway may generally follow the riverward limits of development provided that:

(a) The calculated elevation of the base flood would not be increased more than 0.5 of a foot as a result of any adjustment to the floodway;

(b) Floodway lines are compatible with local land use plans; and,

(c) The flood fringe does not contain appreciable areas with flood velocities greater than 3 feet per second or flood depths greater than 3 feet.

(3) After delineation of a suggested designated floodway and prior to the public hearing to consider the floodway delineation, the department shall meet with local planning officials to consider possible adjustments due to land use considerations. No adjustments in floodway width or location may be made if the theoretical increase in flood heights would exceed 0.5 foot or if adjustments affect private property rights.

History: Sec. 76-5-201, 76-5-202, and 76-5-208, MCA; IMP, Sec. 76-5-201 and 76-5-202, MCA; NEW, Eff. 9/4/74; AMD, 1989 MAR p. 1665, Eff. 10/27/89.