Wetland Delineation Services

Chicago, IL

The City of Chicago Department of Transportation (CDOT) is responsible for the design and maintenance of all City-owned roadways. As a part of the Jackson Park revitalization and re-design, to accommodate planned development and traffic reconfiguration, CDOT requested a wetland delineation of the entire 740-acre park and surrounding area.

GSG wetland scientists conducted a wetland delineation, identifying wetlands, and other potential waters of the United States (WOUS) that occurred within the project area. Prior to the field investigation, a desktop assessment was conducted, inventorying existing resource information, to determine the likelihood of identifying wetlands within the project area, and locating potential areas to investigate further. Available resource information included soil surveys, floodplain maps, wetland inventories, topographic surveys, and USGS topographic mapping.

A meander survey was conducted throughout the project area, specifically targeting areas identified during the desktop assessment. When potential wetland or WOUS areas were observed, paired data points were analyzed to identify the jurisdictional boundary of the wetland feature, one point within the wetland, the other outside of the wetland. A sub-meter GPS unit was used to record the location of the wetland boundary in the field for later identification.

A floristic quality inventory (FQI) was conducted within each wetland identified, identifying all unique plant species that occurred within each wetland. The FQI was used to determine the relative quality of the wetland, based on the diversity and number of native species present.

Following the field investigation, a wetland delineation report was prepared that documented the findings of the desktop and field investigation. GSG will use the findings of the wetland delineation to prepare the Illinois Department of Transportation (IDOT) Wetland Impact Evaluation (WIE) form when project designs are finalized.