US Army Corps of Engineers
Chicago District

Saganashkee Slough-McMahon Woods


Section 506, Great Lakes Fishery & Ecosystem Restoration (Section 506 WRDA 2000, as amended) 

Local Sponsor:

     Forest Preserves of Cook County

Project Description:

The Saganashkee Slough-McMahon Woods is a portion of a greater natural area, called Palos Preserves (~6,000-ac), primarily owned and managed by the FPDCC. The study area is within the historic boundary of the Great Lakes basin and borders the Calumet-Saganashkee (Calumet-Sag) Channel near Palos, Ill., in Cook County. The Forest Preserves of Cook County has in turn requested that the Chicago District, US Army Corps of Engineers (USACE) initiate a study under the Section 506 Great Lakes Fishery and Ecosystem Restoration (GLFER) authority to determine the feasibility of restoring important critical wetland and wildlife habitat within Saganashkee Slough-McMahon Woods. Preliminary evaluation of the project site resulted in the removal of the Saganashkee Slough portion of the study area because of the high cost to implement measures to address fish habitat problems and concerns from the FPDCC. This report has evaluated the feasibility and environmental effects of restoring geomorphic features, hydrology, marsh and wooded riparian plant communities within McMahon Woods. The scope of this study addresses the issues of altered geomorphology, absence of native plant communities, invasive species, fire suppression, rare wetland/fen communities, degradation of critical habitat for a federally listed species, and poor quality native plant communities.

Current Status:

The feasibility study and supporting documentation was sent out for a 30-day public review in November 2015. The feasibility study was approved in February 2016. The project is on hold due to lack of federal funds.

Current Conditions:




Project Aspects:

The total McMahon Woods study area is approximately 410.6-acres of publicly-protected lands within the Palos Preserves area of the Forest Preserves of Cook County. About 300 acres of the study area is designated critical habitat for the Great Lakes subpopulation of Federally Endangered Hine’s Emerald Dragonfly (Somatochlora hineana). McMahon Woods is located along the Lake Michigan Flyway, which a part of the greater Mississippi Flyway. The Lake Michigan Flyway is notable as one of America’s most important migration routes for songbirds. Songbirds and other groups of birds (e.g., shorebirds, raptors, etc.) migrate from South America to breed in portions of the Upper Midwest all the way to Canada and Alaska. It is critically important to migratory birds that use the Lake Michigan flyway to have optimal stopover habitat and food resources to successfully complete their migration. The shoreline of Lake Michigan and its surrounds, which includes northeast Illinois and McMahon Woods, provides vital natural areas that offer rest and foraging opportunities for tired and hungry migrants.  

Problems within the study area are alteration of hydrology, geomorphology and loss of coverage of native plants. The result of these problems is the alteration of ecosystem function (e.g. light availability, soil nutrient cycling, overflow floodwaters, etc.) and structure (e.g., low coverage and diversity of conservative fire adapted plant species) that has impacted the area’s ability to provide sufficient function and habitat for regional and migratory species. The effects of altered ecosystem function and structure is the overall degradation of the native plant community, decreased suitability of wildlife habitat, and a lack of suitable habitat for state endangered and threatened plant species to expand their range within the project area. Most notable is the continued degradation of a federally endangered species habitat for the Hine’s Emerald Dragonfly.  

This project affords the opportunity not only to address issues associated with the above stated problems, but it also continues the movement to establish coastal and inland refuges within the southern Lake Michigan basin. This project can provide a vital piece to the large-scale Great Lakes restoration area by providing a significant quantity of valuable habitat for federally listed species, locally rare species, and a significant number of migratory and resident bird species. Wetland function is constantly being lost in the southern Lake Michigan basin. Enhancing, restoring and protecting these essential habitats is at the heart of the GLFER program. 

Study Documents:

Feasibility Study and Integrated Environmental Assessment

Appendix A Hydrology and Hydraulics Analysis

Appendix B Civil Design 

Appendix D Geotechnical

Appendix E HTRW

Appendix G Compliance

Appendix H Monitoring and Adaptive Management  

Appendix I Current Conditions

Appendix J Habitat Assessment 


Project Manager

Kirston Buczak


Click map to enlarge:



Click photos to enlarge


Erosion of Hine’s Emerald Dragonfly Rivulet 

Erosion of Hine’s Emerald Dragonfly Rivulet 

 Crook Creek Riparian Area
 Crook Creek Riparian Area