14.01.150 Floodways.
Within areas of special flood hazard established in MMC 14.01.050 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and erosion potential, the following provisions apply:
A. Encroachments, including fill, new construction, substantial improvements, and other development within the adopted regulatory floodway are prohibited unless certification by a registered professional engineer is provided demonstrating, through hydrologic and hydraulic analyses performed in accordance with standard engineering practice, that the proposed encroachment when combined with all other existing and anticipated development would not result in any increase in flood levels within the community during the occurrence of the base flood discharge.
B. Construction or reconstruction of residential structures is prohibited within designated floodways, except for:
1. Repairs, reconstruction, or improvements to a structure which do not increase the ground floor area;
2. Repairs, reconstruction or improvements to a structure, the cost of which does not exceed fifty percent of the market value of the structure, either:
a. Before the repair or reconstruction is started, or
b. If the structure has been damaged, and is being restored, before the damage occurred; and
3. Work done on structures to comply with existing health, sanitary or safety codes or to structures identified as historic places.
C. If subsection (A) of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of MMC 14.01.130(A).
D. In areas with base flood elevations (but in which a regulatory floodway has not been designated), no new construction, substantial improvements, or other development (including fill) shall be permitted within Zones A1-30 and AE on the community’s Flood Insurance Rate Map, unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot at any point within the community.
E. The flood carrying capacity within the altered or relocated portion of any watercourse shall be maintained. (Ord. 004/2006 § 2; Ord. 021/2005 § 1)