Minnehaha County, SD Environmental Rules: Erosion Control (2026)

Minnehaha County does not maintain a stand-alone county erosion-control ordinance separate from its subdivision and stormwater provisions. State-level requirements drive most erosion-control compliance. Under SDCL Chapter 34A-2 (Water Pollution Control) and the SD General Permit for Stormwater Discharges Associated with Construction Activity, any operator disturbing one acre or more (or part of a larger common plan exceeding one acre) must implement a Stormwater Pollution Prevention Plan (SWPPP) with required BMPs: perimeter silt fence, sediment basins for drainage areas of ten acres or more, stabilized construction entrances, dust control, inlet protection, and final stabilization within 14 days of completion. SD DANR follows the EPA Construction General Permit BMP framework. At the local level, the Minnehaha County Subdivision Regulations require erosion-control plans as part of plat submittal for new subdivisions, and the county Floodplain Management Ordinance prohibits unstabilized fill or grading within Special Flood Hazard Areas. Sites along the Big Sioux River bluffs and Skunk Creek corridor are particularly sensitive due to highly erodible loess soils. Agricultural conservation (cropland tillage, terraces, grassed waterways) is administered separately by the Minnehaha Conservation District and USDA Natural Resources Conservation Service (NRCS) under the federal Farm Bill, not the county zoning code. Routine farming operations are exempt from NPDES stormwater requirements under SDCL 34A-2-36 and 33 USC 1362(14).