Finding the Right Sites to Restore Wetlands

ISGS scientists are sharing the methods they use to locate wetland mitigation sites with the Illinois Environmental Protection Agency (IEPA), which supports the restoration and creation of wetlands for water-quality improvement. The methods were developed earlier through research sponsored by the Illinois Department of Transportation to meet that department's wetland mitigation needs.

Choosing the right wetland mitigation site is important because the hydrogeologic conditions needed to form wetlands are quite complex, and failure to meet wetland conditions is common. Project failures ma result in low-quality wetlands and high reconstruction costs.

Survey scientists prepared a report explaining the ISGS screening process they used in a project funded by the IEPA. ISGS hydrogeologists rapidly evaluate candidate sites by examining the site's hydrogeology, landscape setting, soil, and plant types and by studying manmade changes to the site's groundwater and surface water.

Because it is easier to restore wetlands than to create them on nonwetland areas, scientists try to determine if a site had been a wetland before it was settled and drained. Scientists also attempt to determine whether the wetland would be restored by undoing the drains. If not, a nearby wetland with a similar setting could be studied as a model for creating wetlands on the candidate parcel. If the area had not been a wetland in the past and there are no wetlands nearby to use as a model, the risk of project failure would be high and the candidate site would not be recommended.

Because wetlands perform so many valuable functions, including wildlife habitat, flood storage, and nutrient reduction, ISGS scientists expect that their methods will be useful to others who are interested in creating or restoring wetlands, including governmental agencies, consultants, and the general public.

Updated 05/18/2011 SLD