Stormwater is the water that runs off impervious surfaces from rain, snow melt, and surface drainage. Impervious surfaces are hard surfaces where water is unable to soak, or infiltrate, into the ground. Impervious surfaces include paved streets, parking lots, roof tops, and other hard surfaces. Significantly compacted yards can act as an impervious surface too. This water drains overland collecting sediment, contaminants, litter, nutrients, and other pollutants. The stormwater then discharges into the creeks and ponds in Ankeny untreated.
Why Do We Manage Stormwater?
The city of Ankeny is required by the Iowa Department of Natural Resources (IDNR) to have a National Pollutant Discharge Elimination System (NPDES) Permit. This permit regulates the management of stormwater in Ankeny.
Unmanaged stormwater can cause water pollution, stream bank erosion, and flooding. As more areas of the City are developed into homes and businesses, less precipitation can infiltrate into the ground and more stormwater runoff is generated. By slowing down the stormwater through Best Management Practices (BMPs), the pollutants have a chance to settle out. These practices can help improve the water quality of our streams and ponds and help improve the water quality downstream in our state's rivers.