Dakota County, MN Environmental Rules: Stormwater Management (2026)

07 of the county's Shoreland and Floodplain Management Ordinance splits stormwater duties into general and specific standards. The general standards direct developers to rely on constructed wetlands and vegetated soil surfaces to convey, store, filter and retain runoff before it reaches public waters, and to plan development to minimize disturbed area, runoff velocity and erosion, stabilizing disturbed ground as soon as possible. Where natural features cannot handle the runoff, the ordinance requires engineered facilities such as diversions, settling basins, skimming devices, dikes, waterways and ponds, and any settling basin built to intercept urban runoff must be sized for at least a 10-year storm event.

The specific standards add a hard numeric ceiling: impervious surface coverage on a shoreland lot cannot exceed 25% of the lot, a limit enforced by the Zoning Administrator during permit review. Constructed stormwater facilities must carry documentation from a qualified individual showing they meet the field office technical guide of the Soil and Water Conservation District, and projects must also satisfy the standards of the applicable watershed organization. Any newly built outfall discharging to public waters needs filtering or settling of suspended solids and skimming of surface debris before discharge, closing the loop between site design and what actually reaches the lake or river.