Detention Basin & Water Quality

Detention Basins

Detention Basins are facilities constructed or modified to provide for the temporary storage of stormwater runoff and the controlled release by gravity of the runoff at a prescribed rate during and after a flood or storm. They are usually located in new residential, commercial, and industrial developments to help control potential flooding. Detention basins require regular maintenance in order to ensure proper function. Poorly maintained basins lose their ability to control flooding. Homeowners associations and property owners are responsible for maintaining their detention basins. 

Detention Basin Types

  • Dry Detention Basins - A detention basin designed to drain completely after temporary storage of stormwater flows and to normally be dry over the majority of its bottom area.
  • Wet Detention Basins - A detention basin designed to maintain a permanent pool of water after the temporary storage of stormwater runoff. 
  • Stormwater Drainage System - all means, natural or manmade, used for conducting stormwater to, through or from a drainage area to the point of final outlet from a property (canals, channels, ditches, streams, culverts, streets, storm sewers, detention basins, swales and pumping stations).
  • Retention Basin - A facility designed to completely retain a specified amount of stromwater runoff without release except by means of evaporation, infiltration, emergency bypass or pumping.
  • Stormwater Wetlands - similar to set detention basins, but contain more wetland native plants. they also provide fish and wildlife habitat.

Register Location and Contact Information  

For Questions you may call the Public Works Department at 618-692-7535 or email: The Public Works office is located at 200 East Park Street, Edwardsville, IL 62025. 

Maintenance Tips

  • Get a copy of your detention basin plan — contact the Public Works office at 618-692-7535 to determine what type of detention basin is in your neighborhood.
  • Inspect inlet and outlet pipes — check to make sure pipes aren’t crumbling or broken; make sure pipes are free of debris and obstructions; check for erosion around the pipes.
  • Inspect for litter and debris — check for debris near the inlets and basin twice a year and after major storms. Remove debris and dispose of it with your household trash.
  • Examine for erosion— check twice a year and after major storms, filling in damage with topsoil and seeding it with turf grass. If erosion problems continue, contact our office for further guidance.
  • Inspect vegetation — inspect the banks and in the basin, removing dead vegetation. Dead vegetation should be disposed of with other compost materials. 
  • Mowing — frequency depends on the type of detention basin, typically basins will only need to be mowed three to four times a year. Do not fertilize the grass in your detention basin.
  • Keep records — good records will help you make adjustments to your maintenance program as needed. Keep records of all inspections, including dates, names of inspectors, maintenance activities performed, what was observed, and costs.
  • Reporting - A city inspector will periodically inspect the detention basin to ensure compliance. A copy of the Detention Basin Inspection Checklist is available for your review.
  • Request City Inspection and/or send photos of current condition