Windmill Lakes Detention Retrofit

Project Description & Location

In 2005, the City approved working with the Conservation Foundation to improve the Windmill Lakes Detention Basin. The basin is located just southwest of the car wash at the corner of Main Street and Randall Road and is a traditional dry bottom detention basin. The basin was originally built as an online detention basin where an old creek bed came from the north. The basin drains to the south into a high-quality wetland along Mill Creek that is also maintained by the Conservation Foundation.

Threatened Wetlands

The quality of this wetland is threatened because the Windmill Lakes basin has maintenance and operational problems that have resulted in polluted and sediment-laden stormwater being discharged directly into the high-quality area. The Conservation Foundation has received grants to restore this area and remove evasive species from the US Fish and Wildlife Service. However, they have suspended any more grants until something has been done with the basin.


The Conservation Foundation then contacted the City about retrofitting the basin as a demonstration project by retrofitting a stormwater management facility with best management practices. They also consulted with the U.S. Army Corps of Engineers Regulatory Branch staff in Chicago, and they concurred with the feasibility of the project. In addition, the Corps will be funding the retrofitting of the basin. However, to receive the funds for the basin improvements the land must be dedicated to an entity who will maintain as it is improved. As the Conservation Foundation manages wetlands under easements but does not own them, they approached the City to own the basin.

The City and the Conservation Foundation met with the developer of Windmill Lakes and Holy Cross Church regarding the project. The creek that drains into the basin goes across the church lot north of the basin. The creek has many evasive species along with it and is included as part of the best management plan for the basin. After the meeting, the Windmill Lakes developer agreed to dedicate the basin to the City and several other lots including a buildable lot while the church donated their portion north of the basin as well so the city owns the entire drainage area to apply funds toward.

Project Updates

Currently, Encap, Inc. manages the basin on behalf of the City and the Conservation Foundation. They go out to the site multiple times during the growing season to apply herbicide and monitor erosion. Plans

The engineering plans have been completed for retrofitting the basin along with the planting plan and are available for viewing below.

Planning Documents