Floodplain Maps

Maps of Floodplains

Floodplain maps provide the basis for floodplain management, regulation, and insurance requirements by identifying flood-prone areas that may threaten life and property. Floodplain maps are reviewed and approved by FEMA. Once approved, the floodplain maps guide flood management programs, including floodplain regulation, safety, preservation, preparation and mitigation.

Re-Evaluation of Flood Hazards

FEMA completed a re-evaluation of the flood hazards in our community and has provided new Flood Insurance Rate Maps (FIRM’s) and Flood Insurance Study (FIS) report which are effective March 22nd, 2023. The new floodplain mapping is based on updated topographic, and in some cases, revised hydrologic and hydraulic analysis.

Map Service Center

Use the FEMA Map Service Center to access a Public Flood Map or a Flood Insurance Rate Map.

If you'd like assistance on floodplain information, please complete the  Floodplain Information Request Form (PDF) and either fax it to 605-642-1337 or drop it off in-person at the Building & Development Office at 625 N. 5th Street, 2nd Floor.

Floodplain Map Changes

Floodplain maps are periodically updated and revised to reflect changing conditions, such as impacts of flooding, new topography, land development, updated mapping studies, and construction of floodplain improvements.

• Spearfish Creek - Floodplain Comparison (arcgis.com) - this is the comparison of the old flood plain to the new. Clicking on the layer of sheets in the upper right-hand corner switches between floodplain and floodway.
• Spearfish Floodplain Comparison- Story Map (arcgis.com) - is the link to the before and after map.

Map Forms

Floodplain map changes can take several forms such as:

• Conditional Letters of Map Amendment (CLOMAs)
• Conditional Letters of Map Revision (CLOMRs)
• Conditional Letters of Map Revision based on Fill (CLOMRFs)
• Flood Insurance Rate Maps (FIRMs) or Digital Flood Insurance Rate Maps (DFRIMs)
• Letter of Map Revision (LOMRs)
• Letters of Map Amendment (LOMAs)
• Letters of Map Change (LOMCs)
• Letters of Map Revision Based on Fill (LOMRFs)
• Local Map Changes