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
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.