This section establishes performance standards for development located in flood-prone areas with drainage areas less than 640 acres:
(A) Flood-carrying capacity. The flood-carrying capacity shall be maintained for channels with flood-prone areas draining a tributary area of 20 acres or more.
(B) Flood-prone area conveyance, velocities, flood profiles, and flood storage.
(1) For all development within a flood-prone area where the tributary drainage area is 100 acres or more, the applicant shall meet the requirements of § 151.149 according to the following criteria and submit to the Lake County Stormwater Management Commission for permit or approval:
(a) An engineering study performed by a licensed professional engineer which will determine a floodway which meets the definition of the regulatory floodway and show the proposed development will meet all applicable requirements of § 151.147;
(b) An engineering study performed by a licensed professional engineer which will determine a base flood elevation and demonstrate that the proposed development will maintain the existing condition’s conveyance, will not increase flood velocities, will not increase flood profiles, and will provide hydraulically equivalent compensatory storage at a ratio of 1.2 to one. Such compensation areas shall be designed to drain freely and openly to the channel and located opposite or adjacent to fill areas in a manner that is hydraulically equivalent; or
(c) An engineering study performed by a licensed professional engineer which will demonstrate, for a range of flood elevations (which would exceed the expected 100-year flood elevation), the proposed development will maintain the existing condition’s conveyance, will not increase flood velocities, will not increase flood profiles, and will provide hydraulically equivalent compensatory storage at a ratio of 1.2 to one. Such compensation areas shall be designed to drain freely and openly to the channel and located opposite or adjacent to fill areas.
(2) For all development within a flood-prone area where the tributary drainage area is more than 100 acres, the applicant shall meet the requirements of § 151.147.
(Ord., § 8.10, passed 10-13-2009; Ord. passed 10-9-2012; Ord. 23-1056, passed 8-8-2023)