Rapid City, SD Environmental Rules: Flood Zones (2026)

060 adopts the FEMA Flood Insurance Study for Pennington County, South Dakota and Incorporated Areas, dated June 3, 2013, and its accompanying Flood Insurance Rate Maps (FIRMs) as the basis for the city's special flood hazard areas; copies are kept at the Public Works Department's Engineering Services Division, 300 Sixth Street. 120, no one may develop in a special flood hazard area without first filing a written application with the Floodplain Administrator and obtaining a floodplain development permit, paying a fee set by Common Council resolution.

The application must identify the development, describe the land, and include a site plan showing flood zone boundaries, floodway boundaries, base flood elevations, ground elevations and any proposed fill, excavation or drainage work. A permit becomes invalid if the authorized work is not started within 180 days of issuance, or is suspended for 180 days once begun; the Floodplain Administrator can grant up to two extensions of no more than 180 days each on a written, justified request. The Administrator can suspend or revoke a permit issued on incorrect or incomplete information, and the Building Official can block occupancy of a structure or site built in violation of the chapter.

Improvements to an existing structure that, combined with improvements made over the prior 20 years, reach or exceed 50% of its current market value trigger a requirement to bring the whole structure up to current floodplain standards. 300.