10-5-2-4: FLOODWAYS:

Located within the special flood hazard areas established in section 10-3-2 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of the floodwaters which carry debris, potential projectiles, and erosion potential, the following provisions apply:

   A.   Prohibit encroachments, including fill, new construction, substantial improvements, and other development within the adopted regulatory floodway unless:

      1.   Certification by a registered professional civil engineer is provided demonstrating through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachment shall not result in any increase in flood levels within the community during the occurrence of the base flood discharge; or

      2.   A community may permit encroachments within the adopted regulatory floodway that would result in an increase in base flood elevations, provided that a conditional letter of map revision (CLOMR) is applied for and approved by the Federal Insurance Administrator, and the requirements for such revision as established under Volume 44 of the Code of Federal Regulations, section 610-5-1-12 are fulfilled.

      If an encroachment proposal resulting in an increase in base flood elevation meets the following criteria:

         a.   Is for the purpose of fish enhancement;

         b.   Does not involve the placement of any structures (as defined in section 10-2-1) within the floodway;

         c.   Has a feasibility analysis completed documenting that fish enhancement will be achieved through the proposed project;

         d.   Has a maintenance plan in place to ensure that the stream carrying capacity is not impacted by the fish enhancement project;

         e.   Has approval by the National Marine Fisheries Service, the State of Oregon Department of Fish and Wildlife, or the equivalent federal or state agency; and

         f.   Has evidence to support that no existing structures will be negatively impacted by the proposed activity.

      Then an approved CLOMR or may be required prior to approval of a floodplain permit.

   B.   If the requirements of section 10-5-2-4A are satisfied, all new construction, substantial improvements, and other development shall comply with all other applicable flood hazard reduction provisions of section 10-5-1. (Ord. 666-20, 10-13-2020)