(a) Development within the special flood hazard area shall result in no net loss of natural floodplain storage. The volume of the loss of floodwater storage due to development shall be offset by providing an equal or greater volume of permanent flood storage by excavation or other compensatory measures at or adjacent to the development site. This compensatory floodplain storage shall be proposed and created in accordance with the following requirements:
(1) Prior to issuance of a stormwater management permit, a plan and calculations prepared by a professional engineer shall be submitted for approval. This plan shall be based on a field survey, shall show the existing and proposed grades of the development and compensatory storage areas, and shall be accompanied by calculations which demonstrate that the proposed stage vs. storage volume relationship of the compensatory storage area would have the same or greater storage volume at each stage as in the pre-development condition of the proposed development area.
(2) The compensatory storage area shall have a hydraulic connection to the affected watercourse which is equal to or greater than the pre-development conditions and shall provide the same or improved rate of flood storage capture and discharge over the course of the flood event as in the pre-development conditions.
(3) Compensatory storage shall be located adjacent to the development area or on the opposite side of the stream across from the development area. In the case of filling for a new stream crossing, the compensatory storage shall be located upstream of the crossing.
(4) The compensatory storage area shall be a permanent component of the property, and shall be repaired or replaced by the owner of the property if silted-in or otherwise compromised by activities other than natural movement of the stream.
(5) Where the applicant proposes compensatory storage on property owned by others, the applicant shall submit a written agreement between such landowner and the applicant wherein the landowner agrees to convey an easement or other property interest or right to the applicant allowing compensatory storage, and to permanently maintain such area for flood storage purposes, as described in paragraph (a)(4) hereof.
(6) The design and creation of the development and compensatory storage areas shall incorporate best management practices as required by other Medina County regulations or State or Federal agencies to minimize soil erosion and sediment impacts.
(7) Prior to grading or construction in development and compensatory storage areas, the applicant shall be responsible for obtaining any necessary permits or approvals from other involved agencies such as the Army Corps of Engineers and the Ohio EPA.
(8) Prior to grading or construction in development and compensatory storage areas, the Floodplain Administrator shall determine if the applicant shall submit technical data regarding the proposed flood boundary revision to FEMA and obtain a conditional letter of map revision (CLOMR) in accordance with Section 1386.21(a). A request for determination shall be submitted in writing to the Floodplain Administrator. Approval shall be granted as required under Section 1386.16.
(9) After the development and compensatory storage areas are complete, an as-built topographic survey of the development area and the compensatory storage area shall be prepared and stamped by a professional surveyor and submitted to the Floodplain Administrator. This survey shall be accompanied by as-built stage vs. storage volume calculations certified by a professional engineer as described in paragraph (a)(1) hereof.
(10) After the development and compensatory storage areas are satisfactorily complete, the applicant shall submit technical data to and obtain a letter of map revision from FEMA in accordance with Section 1386.21(a). When the development and compensatory storage areas are created for a new subdivision development, the letter of map revision shall be obtained prior to the Medina County Engineer's approval of the final subdivision plat.
(b) These regulations regarding compensatory storage shall not apply to public highway, transportation, or drainage improvements or maintenance thereof undertaken by a government agency or political subdivision.
(Ord. 2008-90. Passed 7-7-08.)