Located within areas of special flood hazard established in § 151.113 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) Except as provided in division (C) below, prohibit encroachments, including fill, new construction, substantial improvements and other development unless certification by a registered professional civic engineer is provided demonstrating through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge.
(B) If division (A) above is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this subchapter.
(C) Projects for stream habitat restoration may be permitted in the floodway provided:
(1) The project qualifies for a Department of the Army, Portland District Regional General Permit for Stream Habitat Restoration (NWP-2007-1023); and
(2) A qualified professional (a Registered Professional Engineer; or staff of NRCS; the county; or fisheries, natural resources or water resources agencies) has provided a feasibility analysis and certification that the project was designed to keep any rise in 100-year flood levels as close to zero as practically possible given the goals of the project; and
(3) No structures would be impacted by a potential rise in flood elevation; and
(4) An agreement to monitor the project, correct problems and ensure that flood carrying capacity remains unchanged is included as part of the local approval.
(Ord. 372, passed 12-8-1997; Ord. 414, passed 1-11-2010; Ord. 421, passed 3-10-2014)