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Wetland Assessment

Illinois State Toll Highway Authority Cook County, IL

Roux Associates, Inc. (Roux) was contracted by an engineering consultant to provide
environmental services for the Phase I Transportation Engineering Design of the Project Master Plan for the proposed rehabilitation and add lane project on the I-90 Northwest Tollway between Mile Post (MP) 10.6 (IL 53) and MP 18.0 (Higgins Road) in Cook County, Illinois (I-90 Project). The Project Master Plan is for proposed roadway widening, bridge widening, and interchange ramp modifications. This work includes the addition of one mainline lane in each direction, plus auxiliary lanes where required as determined by analysis. Roux's services were categorized into six tasks: Wetlands; Biological Resources; Streams, Lakes, and Waterways; Cultural, Historical, and Archeological Resources; Agricultural Resources; and Landscape, Erosion, and Sediment Control.

The services for each task pertain to all areas within the I-90 Project corridor. The project corridor included all areas within the current 400-foot right-of-way, as well as an additional 50 feet beyond that right-of-way. This totals a 500-foot wide section of the I-90 Northwest Tollway and extends from MP 10.6 to MP 18.0. The following deliverables were included in Roux Associates' services:

  • Environmental Studies Inventory Sheet (ESIS) Form Part I
  • Wetland Determination Memorandum and Report
  • Wetland Technical Memorandum or Report
  • IDNR Consultation
  • Memorandum of Biological Resource Findings
  • Streams, Lakes, and Waterways Memorandum
  • Cultural Resource Memorandum
  • Agricultural Resource Memorandum
  • Landscape, Erosion, and Sediment Control Memorandum

Roux Associates' services included a site walkover to assess the environmental concerns related to each of the six project tasks, including wetlands, natural areas, riparian environments, flood plains, habitats, and their associated buffer areas. The vegetation, hydrology, and soil conditions were documented during a wetland delineation of the project corridor. Roux Associates' services involved best management practice analysis for landscape design, erosion control, and sediment control to ensure the visual and environmentally aesthetic components of the project. Roux Associates' services included a regulatory review to identify appropriate agencies and permit submittals related to environmental services within the project corridor.