Stormwater Basins

Stormwater Basins are designed to capture, store, and may also treat runoff for pollutants.  These stormwater storage systems use locally adapted plants and can range from being mostly dry between storm events to having a permanent pool of water.  There are several types of stormwater basins:

  • Dry Detention Basin - A basin that remains dry except for short periods following large rain or snowmelt events.  
  • Extended Dry Detention Basin - A dry detention basin that has been designed to increase the length of time that stormwater will be detained, typically between 24-40 hours. This type of basin is not effective at removing nutrients such as phosphorus and nitrogen, unless some type of treatment is incorporated into the lower stage of the design (i.e., forebay, shallow marsh, etc.). 
  • Wet Detention Basin - A basin that contains a permanent pool of water that will effectively remove nutrients in addition to other pollutants. 
  • Extended Wet Detention Basin - A wet detention basin that has been designed to increase the length of time that stormwater will be detained, typically between 24-40 hours. 
  • Retention Basin (Wet Pond)  - A stormwater management facility designed to capture runoff that does not discharge directly to a surface water body. The water is “discharged” by infiltration or evaporation.  

Locally adapted wetland plants should be used in basin design and a permanent buffer strip of natural vegetation of at least 15 feet is required. No lawn care chemicals may be applied within the buffer area except the treatment of invasive species by MI certified pesticide operators. Mowing is allowed twice per year.

Detention Basin Factsheet - SEMCOG


Maintenance is critical for stormwater basins to function and look nice over the years. Having a maintenance plan in place will help ensure the completion of tasks and that an appropriate timeline is followed. It is recommended to have a stormwater basin expert or environmental engineer inspect the basin. Routine tasks include:

  • Inspection of inlet pipes, catch basins, forebay, and outlet structures
  • Removal of sediment, debris, and trash
  • Appropriate mowing outside of buffer zone
  • Removing weeds and replacing plants that do not survive

Maintaining Your Detention Pond Guidebook - Alliance of Rouge Communities

Prevent Algae Blooms

Excess algae in your stormwater basin can cause conditions that kill healthy and beneficial vegetation, harm wildlife, and diminish overall aesthetics.

  • Establish a healthy buffer of vegetation around the basin and wetland vegetation within it
  • Eliminate the use of fertilizers in surrounding areas and have a chemical-free buffer zone
  • Stop grass clippings from getting into the basin