Construction Site Erosion and Sediment Control (COSESCO)
The City has adopted an ordinance that requires proper soil erosion and sediment control on all sites for which a National Pollutant Discharge Elimination System (NPDES) permit is required. This is mandated by the MS4 Permit from the Iowa DNR and is enforced by the City. The ordinance addresses waste at construction sites that may adversely impact water quality and includes sediment loss, building materials, concrete truck washout, chemicals, solid waste, and sanitary waste. The ordinance gives the City authority to issue stop work orders if permit holders are not compliant with terms of their NPDES Permit. A copy of the ordinance is below.
Erosion Control Is Important
Rain events, melting snow, and wind can cause erosion of sediment from construction sites into the storm sewer system and Ankeny's water bodies.
Sediment entering stormwater degrades the quality of water for drinking and habitat. The eroded sediment can cause the storm drains and pipes to clog and cause localized flooding. Sediment increases the amount of turbidity in the nearby creeks and ponds which makes the water cloudy, impacting aquatic life.
For these reasons, the Iowa Department of Natural Resources (IDNR) NPDES General Permit Number 2 and the City of Ankeny's Municipal Separate Storm Sewer System (MS4) permit require that all construction activity over one acre develop a Stormwater Pollution Prevention Plan (SWPPP) in order to minimize the amount of erosion coming off each site.
The City of Ankeny is mandated by their MS4 permit to inspect Ankeny construction sites and see that they comply with the IDNR General Permit Number 2 and other state and local regulations.
Maintaining on-site erosion controls is key in decreasing stormwater pollution. The City does have the authority to stop work on construction sites if erosion controls are missing or are not maintained.
To find more information on erosion controls, view Section 9040: Erosion and Sediment Control of the Statewide Urban Design and Specifications Manual.