Land located in the floodway of a 100-year flood event as defined by Montana Code Annotated title 76, chapter 5, or other land designated by the governing body to be subject to flooding may not be subdivided for building or residential purposes or other uses that may increase or aggravate flood hazards to life, health or welfare, or that may be prohibited by state or local floodplain or floodway regulations.
A. Flood Hazard Evaluation Required: If any portion of a proposed subdivision is within two thousand (2,000) horizontal feet and twenty (20) vertical feet of a live stream draining an area of twenty five (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.
B. Submittal Of DNRC Report: The subdivider shall be responsible for assuring the DNRC submits its report to the subdivision administrator prior to the hearing or meeting on the subdivision application.
C. Requirement Waived: The above requirement is waived if the subdivider contacts the water resources division and that agency states, in writing, that available data indicate that 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. (Ord. 784, 8-6-2007)