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Stormwater Management

Stormwater drainage

The efficient and timely handing of stormwater is important to the quality of our drinking water. Rain water, melting snow and other water sources wash chemicals and other pollutants into natural water sources like rivers and lakes. And, when it is cleaned for drinking, the process becomes more difficult and costly.

Through its stormwater management plan, the City of Johnston has identified various techniques and projects that help to reduce the amount of runoff and in turn, help to protect our drinking water.

The City of Johnston maintains a Municipal Separate Storm Sewer System and is responsible for compliance with the MS4 permit. The permit is issued by the Iowa Department of Natural Resources and renewed every 5 years. 

Compliance for the MS4 permit is divided into six categories:

  1. Public Education and Outreach
  2. Public Involvement and Participation
  3. Illicit Discharge Detection and Elimination
  4. Construction Site Storm Water Runoff Control
  5. Post-Construction Storm Water management
  6. Pollution Prevention and Good Housekeeping

Watershed Assessment and Stormwater Management Plan

The City of Johnston's Watershed Assessment and Stormwater Management Plan includes a variety of best management practices (BMP) to achieve the desired results. A partial list of these approaches includes raingardens, street swales, bioretention areas, subsurface treatment systems, constructed wetlands, and streambank improvements.

Construction Requirements

If you are building in the City of Johnston, varoius requirements must be met