Subd. 1. Permissible uses.
A. The uses listed in § 12.13, Subd. 1, Floodway District, shall be permitted uses.
Subd. 2. Procedures for floodway and flood fringe determinations in General Flood Plain District.
A. Upon receipt of an application for a permit or other approval within the General Flood Plain 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. In the absence of such data, the applicant must furnish such of the following information as is deemed necessary by the Zoning Administrator for the determination of the regulatory flood protection elevation and whether the proposed use is within the Floodway or Flood Fringe District.
1. A typical valley cross-section(s) showing the channel of the stream, elevation of land areas adjoining each side of the channel, cross-sectional areas to be occupied by the proposed development, and high water information.
2. Plan (surface view) showing elevations or contours of the ground, pertinent structure, fill, or storage elevations, the size, location, and spatial arrangement of all proposed and existing structures on the site, and the location and elevations of streets.
3. Photographs showing existing land uses, vegetation upstream and downstream, and soil types.
4. Profile showing the slope of the bottom of the channel or flow line of the stream for at least 500 feet in either direction from the proposed development.
B. The applicant is responsible for submitting one copy of the above information to a designated engineer or other expert person or agency for technical assistance in determining whether the proposed use is in the Floodway or Flood Fringe District and to determine the regulatory flood protection elevation. Procedures consistent with Minnesota Regulations 1983, Parts 6120.5000 through 6120.6200 and 44 CFR Part 65 shall be followed in this expert evaluation. The designated engineer or expert is strongly encouraged to discuss the proposed technical evaluation methodology with the respective Department of Natural Resources Area Hydrologist prior to beginning the analysis. The designated engineer or expert shall:
1. Estimate the peak discharge of the regional flood.
2. Calculate the water surface profile of the regional flood based upon a hydraulic analysis of the stream channel and overbank areas.
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 shall be required if, as a result of the additional stage increase, increased flood damages would result. An equal degree of encroachment on both sides of the stream within the reach shall be assumed in computing floodway boundaries.
C. The Zoning Administrator or his or her designee shall review the technical evaluation and findings of the designated engineer or expert, in conformance with accepted engineering practices. Based on this review, the Zoning Administrator may formally accept the technical evaluation and the recommended Floodway and/or Flood Fringe District boundary or deny the permit application. If questions remain, the Zoning Administrator may present the technical evaluation and findings of the designated engineer or expert to the governing body for acceptance or denial. The Zoning Administrator, prior to official action, may submit the application and all supporting data and analyses to the Federal Emergency Management Agency, the Department of Natural Resources or the Planning Commission for review and comment.
1. In the Floodway District, as determined by the analysis in Subd. 2, Subpar. B above, development may increase the regional flood stage by up to one-half foot, provided that flood damage potential to any existing structure is not increased.
2. In the Flood Fringe, as determined by the analysis in Subd. 2, Subpar. B above, the regulatory flood protection elevation must include a stage increase of one-half foot.
(Ord. 602, passed 8-19-13)