TWM worked on this design-build project with Impact Strategies to increase parking capacity for the main terminal, install a rental/employee parking lot, and address drainage concerns. TWM provided the civil site layout, grading plans, storm sewer design, site drainage analysis for detention, and construction layout and also coordinated approvals through the City, Airport, and regulating agencies.

Scope of Work

  • Stormwater management facilities accounting for proposed and existing undetained drainage areas

  • ADA-compliant sidewalks, walkways, and parking facilities for passengers, employees, and rental cars

  • Reviewed existing parking layout and provided conceptual striping plans to determine best fit


Public Building Commission of St. Clair County, IL / Impact Strategies


Mascoutah, IL


  • Coordination with regulating agencies presiding over proposed project
  • Stormwater management policies and requirements


Land Development
Construction Phase Services