The Forest Preserves is performing a comprehensive restoration of the 528-acre Tinley Creek Ravines starting in fall 2019. Served by the Catalina Grove Family Picnic Area parking lot and bounded by 143rd St, Harlem Ave, 151st St and 80th Ave, this area represents one of the highest priority sites for ecological restoration in southwest Cook County. The goal of the restoration is to create a mix of healthy oak woodland and restored prairie that can be sustainably enjoyed by the public. Questions? Contact TCRproject@cookcountyil.gov.
On this page:
Tinley Creek bisects the area, flowing from west to east toward the Cal-Sag Channel. A network of ravines and intermittent streams feed the creek, creating a unique landscape. Most of the ravines contain remnant oak-hickory woodlands that appear to have escaped plowing or logging, though nearby farmers may have grazed cattle here before this land became a forest preserve.
Today the woodlands retain a canopy of mature oaks, but due to decades of fire suppression the understory beneath these oaks is dense with ironwood, sugar maple and hickory tree saplings. The unnaturally high tree density crowds the natural spread of the oaks’ limbs and limits the amount of light reaching the ground. Without enough light, native plants that support insects, birds and other wildlife cannot thrive here.
Without a sufficient ground-layer of native plants, topsoil washes away as water flows into the ravines. An extensive network of unofficial foot and bike trails has worsened the erosion.
Other portions of the site were disturbed by farming and currently contain a mix of non-native grasses, scattered prairie plants and woody vegetation.
Fortunately, the woodlands still contain pockets of high-quality ground-layer vegetation, an indication that with ecological management the Forest Preserves can restore the Tinley Creek Ravines to a healthy, diverse woodland that supports a robust ecosystem of native plants and animals.
The Forest Preserves Resource Management Department is coordinating and managing this project. Under their direction, contractors are thinning unnaturally dense native trees and removing invasive tree and brush species from approximately 500 acres of woodland. This work will restore a diverse ground layer of plants, enhance native wildlife habitat, reduce erosion and allow the soil to absorb more stormwater.
During growing seasons, Forest Preserves staff and contractors will conduct follow up vegetative and woody invasive species control.
The Forest Preserves will also address areas of excessive erosion through hydrologic repairs and design a less-damaging informal trail network through the preserve.
The restoration work is scheduled to start in fall 2019 and continue through 2024.
Funding & Water Main Project
This project is creatively funded through a partnership with the Oak Lawn Regional Water System, which serves 12 suburban municipalities (Country Club Hills, Matteson, Mokena, New Lenox, Oak Forest, Oak Lawn, Olympia Fields, Orland Hills, Orland Park, Palos Hills, Palos Park and Tinley Park) in southwest Cook County.
As the lead municipality for the water system, the Village of Oak Lawn applied for a license to locate approximately five miles of new water main through the ComEd utility right-of-way that includes a section that bisects the Tinley Creek Ravines area. The new water main would extend from 131st St and 76th Ave in Palos Heights to the north to 163rd St and Central Ave in Oak Forest on the south.
While the water main project will temporarily disrupt portions of the Tinley Creek Trail System, the license fees will cover the costs of Tinley Creek Ravines restoration work and the relocation of portions of the Tinley Creek Trail System to the ComEd utility right-of-way.
The Forest Preserves believes the benefits to the 528-acre Tinley Creek Ravines and the Cook County residents served by the water main project will be worth the short-term impacts.
Frequently Asked Questions
If you have any additional questions, please send them to TCRproject@cookcountyil.gov. This page will be updated as the project progresses.
Will mountain biking be allowed at the site?
Off-road mountain biking on unpaved surfaces is not allowed at this forest preserve due to fragile habitat and high levels of erosion at this site. T he Forest Preserves recognizes that mountain biking has been occurring at this site for many years. The Forest Preserves also recognizes that biking is not the only contributor to trail erosion at this site. The trails that exist at this site have not been constructed to accommodate mountain biking, nor are they maintained. The Forest Preserves is not open to adding single track mountain bike trails or recognizing it as a legal activity at this location.
The closest mountain biking trails are on the Palos Trail System.
Will hiking be allowed at the site?
Yes. There are a few areas that are prone to erosion that the Forest Preserves will be trying to fix and, as such, will be limiting access to these areas to prevent further damage. The Forest Preserves is also considering formalizing a trail loop that would be mapped and marked with wayfinding signage. This new trail would be maintained by the Forest Preserves, while most of the existing foot paths would remain without maintenance.
How long will the project take?
The biggest and most noticeable work will be tree thinning and brush removal. It is anticipated that the entire property will be worked on during winter 2019-20, from November through March. It is possible that the work will extend into the winter 2020-21 if it can’t be completed within the first year due to weather conditions or other issues.
Work in the growing season (spring – fall) will be ongoing for 3-5 years, but will be sporadic. Growing season work will focus on invasive species control and suppression of woody vegetation that is being targeted for clearing.
Prescribed fires will be implemented on the property, typically in either November or March.
Hydrology repairs are likely to begin in winter 2019, with the main work happening in the summer or fall of 2020.
Water main installation is not likely to occur before 2021.
Will the site be accessible during the project?
Yes, however the Catalina Grove parking lot will be closed from November 1, 2019 through March 1, 2020. There will be multiple contractors moving in and out of the site and they will be utilizing the parking lot for staging and access.
If you plan to be visit this winter, please use caution and obey signage in and around the work zones. Up to 50 people may be working at any given time, often using machinery. Trees will be removed and conditions may be hazardous to foot traffic at times.
Will the water main installation affect the bike trail?
The bike trail will be impacted adjacent to Turtlehead Lake, to the north of the Tinley Creek Ravines property. Prior to construction, the trail will be rerouted and a new connection will be built to link the trail to the Turtlehead Lake parking lot. This new section of trail will stay open during construction, and will be the new alignment post-construction. There may be temporary closures of the bike trail near Catalina Grove when the water main is being installed, but that is unknown at this time.
What will be the boundaries of the restoration project?
The plan is to work to the entire extent of the property boundaries. Harlem Ave to the east, 151st St and private property to the south, private property to the west, and private property/143rd St to the north.
The Forest Preserves is hiring a land surveyor to mark the entirety of the private property boundary in October 2019. You may notice flagging being placed along your property line if you live adjacent to the Forest Preserves. Please do not disturb this flagging as it will allow our contractors to stay on Forest Preserves property. Also note that we will be asking adjacent landowners to stop storing personal property or mowing Forest Preserves land going forward.