(A) Upon receipt of an application for a permit or other approval within the General Floodplain District, the Zoning Administrator must obtain, review, and reasonably utilize any regional flood elevation and floodway data available from a federal, state, or other source.
(B) If regional flood elevation and floodway data are not readily available, or the application involves a project exceeding the lesser of five acres or 50 lots, the applicant must furnish additional information, as needed, to determine the regulatory flood protection elevation and whether the proposed use would fall within the Floodway or Flood Fringe District. Information must be consistent with accepted hydrological and hydraulic engineering standards and the standards in division (C) below.
(C) The determination of floodway and flood fringe must include the following components, as applicable:
(1) Estimate the peak discharge of the regional (1% chance) flood;
(2) Calculate the water surface profile of the regional flood based upon a hydraulic analysis of the stream channel and overbank areas; and
(3) Compute the floodway necessary to convey or store the regional flood without increasing flood stages more than one-half foot. A lesser stage increase than one-half foot is required if, as a result of the stage increase, increased flood damages would result. An equal degree of encroachment on both sides of the stream within the reach must be assumed in computing floodway boundaries.
(D) The Zoning Administrator will review the submitted information and assess the technical evaluation and the recommended Floodway and/or Flood Fringe District boundary. The assessment must include the cumulative effects of previous floodway encroachments. The Zoning Administrator may seek technical assistance from a designated engineer or other expert person or agency, including the Department of Natural Resources. Based on this assessment, the Zoning Administrator may approve or deny the application.
(Ord. 2017-03, passed 7-24-2017)