A Stormwater Management Plan (SWMP) is required for all subdivision and site plan applications, and certain conditionally-permitted uses, and shall be consistent with the Stormwater Management Regulations described in Chapter 8:3.6 of the Johnson County Unified Development Ordinance.

Submittal Guidelines

Who needs to submit a SWMP? 

Site Plans and Subdivision Applications:
An electronic version and one hard copy must be submitted for review and approval, at time of initial development application.

Conditional Use Permits:
An electronic version and one hard copy must be submitted for review and approval.  The timing of submittal for Conditional Use Permits is dependent upon the supplemental conditions outlined in Chapter 8:1.23 of the Johnson County Unified Development Ordinance. 

SWMP Checklist
  • A stormwater drainage report to include:
    • Project narrative describing how stormwater will be addressed.
    • Stormwater calculations, including break-down of pre- and post-developed land use, drainage areas, curve numbers or runoff coefficients, time of concentration, runoff rates, volumes, velocities and water surface elevations. 
    • Stormwater BMP maintenance and repair plan.
    • Design checklist for any proposed infiltration practices (e.g. bioretention cell).
    • A signature block that includes signature lines for the property owner and the PDS Administrator. 
  • Seeding/final stabilization plan.
  • Standard drawings and cross sections, with elevations.
  • Site plain showing locations of stormwater practices, limits of disturbance, overlay of any sensitive areas, and existing and proposed contours. 


Questions? Contact Planning, Development, and Sustainability at 319-356-6083.