(A) Land located in the floodway of a 100-year flood event as defined by M.C.A. Title 76, Chapter 5, or other land determined by the City Planning Staff to be subject to flooding may not be subdivided for building or residential purposes or other uses which may increase or aggravate flood hazards to life, health or welfare, or which may be prohibited by state or local floodplain or floodway regulations.
(B) If any portion of a proposed subdivision is within 2,000 horizontal feet and 20 vertical feet of a live stream draining an area of 25 square miles or more, and no official floodway delineation or floodway studies of the stream have been made, the subdivider shall provide in detail to the Floodplain Management Section of the Water Resources Division of the Montana Department of Natural Resources and Conservation (DNRC), a flood hazard evaluation, including the calculated 100-year frequency water surface elevations and the 100-year floodplain boundaries. This detailed evaluation must be performed by a licensed professional engineer experienced in this field of work. The evaluation must follow the “guidelines for obtaining 100-year flood elevations in Approximate Zone A or unmapped areas” which may be found at the following website: www.mtfloods.org.
(C) The subdivider shall be responsible for assuring the DNRC submits its report to the City Planning Staff, prior to the hearing or meeting on the subdivision application. The above requirement is waived if the subdivider contacts the Water Resources Division and that agency states in writing the available data indicate the proposed subdivision is not in a flood hazard area. However, the DNRC may require additional information following the above guidelines to ensure there are no flood hazards. (Res. 607, passed 7-1-2019)