General Motors Company

Wentzville Assembly Center

Wentzville, Missouri, United States

Certified Silver through 2024

Project Name
Project Type
Northwest Bioswale
Wetlands & Water Bodies
Mount Polomik Native Prairie
Grassland
About the Program
General Motors Company's Wentzville Assembly Center is located in Wentzville, Missouri, about 40 miles west of St. Louis. Managed habitats on- and off-site include about 170 acres of wetlands, streams, grassland and a pollinator garden. The team uses these habitats to support wildlife, improve water quality and spread awareness of habitat conservation within the surrounding community.

Practices and Impacts
  • The team has created and maintained a native bioswale from a drainage ditch that was once filled with cattails. It concentrates and conveys stormwater runoff while removing debris and pollution.
  • The bioswale project seeks to provide shelter, food and space for a variety of native species, while specializing in plants that remove pollutants from stormwater. Progress is measured by conducting quarterly flora and fauna inventories and conducting monthly visual inspections.
  • After the soils were tested, the bioswale was seeded with swamp milkweed, common milkweed, ironweed, purple coneflower, stiff goldenrod, boneset, prairie dock, ox eye sunflower and rattlesnake master.
  • In 2019, the team inventoried 14 native plant species, four invasive plant species and six wildlife species. This inventory signaled a higher proportion of native plants in the bioswale. 
  • The team monitors a one-acre grassland habitat to support pollinator species, with a focus on monarch butterflies. A native pollinator seed mix was planted to replace the gravel habitat. Flora and fauna monitoring occurs to ensure the success of the native plantings and biodiversity. 
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