Recognizing an opportunity to improve water quality, the Village received an Illinois Environmental Protection Agency (IEPA) 319 Water Quality Grant to restore two degraded drainage swales that discharged directly to the Middle Fork North Branch of the Chicago River (NBCR). Both drainage swales were severely eroded, choked with invasive plants, and blocked with sediment and debris.
The primary goals of this project were to improve water quality in the drainage swales, stabilize the side slopes, remove the invasive vegetation that was choking the banks, and facilitate the conveyance of stormwater through the bioswales. A secondary objective of the project was to educate property owners about their impact on water quality and to encourage businesses to adopt green infrastructure alternatives by retrofitting traditional stormwater detention areas.
Gewalt Hamilton completed a topographic survey, wetland delineation, and hydrology study for the identified areas, as well as engineering design of the improvements. Permitting was required through the US Army Corps of Engineers (USACE) and Lake County Stormwater Management Commission (SMC). Vegetation was removed from along the swales, detention basins were developed. Grading was completed to create slopes, and amended soils were added. Check dams, rip rap and erosion control measures were put in place. Plugs were installed, areas were seeded, and an erosion control blanket was installed. The project was completed in August 2013.
In addition to the swale restoration, a rain garden and wet basin were created. A ditch check diverts low flows from the south drainage swale and routes water through the wet-mesic area during storm events. The southern wet basin (approximately 1.03 acres) was created by removing 1.03 acres of impervious pavement and 375 linear feet of storm sewer pipe. The north rain garden (approximately 0.14 acres) was constructed in an area that was previously mowed lawn. Asphalt and gravel removed from the project site was recycled.