Section 506, GREAT LAKES FISHERY & ECOSYSTEM RESTORATION (SECTION 506 WRDA 2000, as amended)
Hegewisch Marsh is a ~131 acre natural area located on the south side of Chicago, with about 119 acres recommended for restoration. The site is bounded to the north by 130th Street, to the east by Torrence Avenue, to the south by USACE property (T.J. O’Brien Lock and Controlling Works), and to the west by the Calumet River (T37N, R14E, S36). The natural area is owned in part by the CPD, Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) and USACE, with overall site management implemented by the CPD. The USACE owns 1.8 acres along the southern edge of the site, and has an access road leading to the T.J. O’Brien Lock and Controlling Works.
This study is a collaboration between the US Army Corps of Engineers (Chicago and Rock Island districts), the Chicago Park District (nonfederal sponsor), the Wetlands Initiative, and Green Corps.
Benefits of the proposed project would include restoring native wetlands and creating a complex ecosystem to benefit fish, amphibians, reptiles, mammals, and migratory birds.
The feasibility study was released for a 30-day agency and public review on May 3, 2017, and closed on June 5, 2017. The feasibility study was approved in September 2017. The feasibility cost sharing agreement was closed out in February 2019. No additional work will be done on this project due to a change in Chicago Park District's priorities.
The wet prairie quadrats average a native species richness of twenty-one (21) species, but when considering the conservatism of the native species present, species composition still exemplifies a highly degraded habitat. The most conservative native species that are present are of moderate conservatism quality (C=5 or 6), and are sparse in abundance and coverage. These few are limited to Cut-Leaf Water-Horehound (Lycopus americanus), Prairie Groundsel (Packera plattensis), Wand Panic Grass (Panicum virgatum), Marsh Mermaidweed (Proserpinaca palustris), Hard-Stem Club-Rush (Schoenoplectus acutus), Mad Dog Skullcap (Scutellaria lateriflora), White Heath American-Aster (Symphyotrichum ericoides). Invading non-native species include Purple Loosestrife (Lythrum salicaria), Reed Canary Grass (Phalaris arundinacea), and Common Reed (Phragmites australis). Photo 5 shows a relatively healthy patch of wet prairie, whereas Photo 6 shows invasion and domination by Green Ash (Fraxinus pennsylvanica) and Reed Canary Grass. The current condition calculated for the Wet Prairie habitat is a Mean C value of 3.0, with an FQI value of 15.0.
Photo 5: Relatively Healthy Wet Prairie Patch
Photo 6: Highly Degraded Wet Prairie Patch with Green Ash and Reed Canary Grass Invasion
The woodland quadrats average a native species richness of 31 species, but when considering the conservatism of the native species present, species composition still exemplifies a highly degraded habitat. The most conservative native species that are present are of a higher conservatism quality (C =7 or 8), and are sparse in abundance and coverage. These are Hairy Pagoda Plant (Blephilia hirsuta), White Grass (Leersia virginica), Long-Sepal Beardtongue (Penstemon calycosus) and Golden Alexanders (Zizia aurea). Moderately conservative (C=5) native species that are present and are sparse in abundance and coverage are Hairy Woodland Brome (Bromus pubescens), Cut-Leaf Water-Horehound (Lycopus americanus), Cup Plant (Silphium perfoliatum), Yellow Indian Grass (Sorghastrum nutans), and White Heath American-Aster (Symphyotrichum ericoides). Invading non-native species include Queen Anne’s Lace (Daucus carota), White Sweet-Clover (Melilotus alba), Parsnip (Pastinaca sativa), Kentucky Bluegrass (Poa pratensis), European Buckthorn (Rhamnus cathartica), and Common Dandelion (Taraxacum officianale). The remaining species are considered low quality, native weeds. Photo 7 shows a relatively healthy patch of woodland, whereas Photo 8 shows invasion and domination by a weedy understory and European Buckthorn. The current condition calculated for the Woodland habitat is a Mean C value of 2.5, with an FQI value of 15.3.
Photo 7: Relatively Healthy Patch of Wet Woodland with Cardinal Flower
Photo 8: Highly Degraded Patch of Woodland with Over Dense Canopy and Buckthorn Invasion
Vernal pools are specific hydrogeomorphic features that are nested within two of the habitat types at Hegewisch Marsh, which are the wet prairie and woodland communities. Floristic inventories of the wet prairie and woodland capture the quality of these, which is primarily dictated by the geomorphic configuration and hydroperiod longevity. There are healthy vernal pools (Photo 9) and unhealthy vernal pools (Photo 10).
Photo 9: Healthy Woodland Vernal Pool with Natural Geomorphology and Hydroperiod Longevity
Photo 10: Highly Degraded Vernal Pool with Poor Geomorphology and Short Hydroperiod
NATURAL RESOURCE PROBLEMS:
Historically, the Hegewisch Marsh natural area was most likely dominated by marsh and wet prairie/savanna riparian to the Calumet River. By the late 1800s, much of these communities in the Calumet Region were converted to urban or industrial use, and agriculture to a lesser degree. Although historic native plant community types and seed banks were eliminated from the site, there are relatively healthy patches of native community types that have formed. These patches are currently persisting, but are under pressure from other highly altered opportunistic plant communities that impose pressure on hydrology and nonnative plant infestation. Human induced disturbances to the remaining natural processes at Hegewisch Marsh include fire suppression, altered hydrology and hydroperiod, and increased colonization of invasive species. Based on site qualitative and quantitative investigations, and the study results above, the main problems at the Hegewisch Marsh in which the 506 Authority may address are as follows:
Hydrogeomorphic conditions that limit native plant richness and abundance
High abundance of invasive, water pumping trees, which reduce water levels and temporal longevity of vernal wetlands and hemi-marsh habitats
Impaired connectivity for reptile and amphibians between Calumet River and Hegewisch Marsh due to bank configuration
Impaired habitat patches due to invasive plant species dominance
Lack of critical habitat for locally endangered and rare fauna
Lack of high quality food source and resting habitat for migratory birds