Ravine 7: A Stream Runs Through It
Mar 31, 2011 11:08AM
● By Gail Goldberger
An exciting project is underway to restore natural stream conditions in a Lake Michigan ravine in Highland Park. This restoration will make the stream more suitable for the return of desirable cold-water fish, lessen erosion and improve water quality in the lake and stream by reducing sediment pollution.
The stream that flows along Ravine Drive, just south of the Highland Park business district, is a beautiful pocket of nature, deep in the glade of a ravine that will make you forget you’re in a suburb of Chicago. Thanks to funding from the federal government, a 400-foot stretch will be enhanced and made healthier for fish that have historically used the stream to spawn. Improvements in stream flow and habitat should increase their numbers, decrease the amount of silt that accumulates and pours into the lake and provide benefits to the ravine and lake ecosystems.
What is wrong with the current stream?
“The entire Lake Michigan watershed, from Winnetka to Waukegan, is made up of streams that run down from Green Bay Road to the shoreline,” says Rebecca Grill, Natural Areas Manager of the Park District of Highland Park (PDHP). “Rain and snow melt coursing through these streams often runs fast, causing erosion of stream banks and sending sediment (soil, which is mostly clay) down to the mouths of the streams, where it drains into the lake. Too much sediment isn’t good for fish, the stream or the lake, and is considered a pollutant.”
Which fish stand to benefit?
Trout—rainbow, brown and brook—all have been spotted in ravine streams in or near Highland Park. Other native fish, such as blunt-nose minnow, longnose dace and white sucker, also may take advantage of the restored habitat. Fish eat bugs (flies, mosquitoes, gnats); are food for birds, amphibians and mammals; and are indicator species, meaning they indicate the quality of our environment (water and habitat). When fish numbers increase and species multiply, there’s a good chance that water quality also is improving.
How will the stream along Ravine Drive be modified?
“The stream will be ‘naturalized’ with beds of small gravel, where fish can lay their eggs in nests (called redds),” says Grill. Five check dams will slow the stream’s velocity, so fish eggs and young fish won’t be washed away when rains are heavy. Deep pools out of the main flow will be created to provide hiding places and cool temperatures, needed by cold-water fish to survive.
These pools and gravel beds will be created where vegetation and tree roots provide further shelter. Rock slabs will be brought in to hang over the pools and redds, providing an extra measure of protection for spawning and rest. Sediment traps will be placed at points in the stream, and sediment will be removed as necessary.
To further “naturalize” the stream, Grill says native vegetation will be planted along the banks to diversify the habitat and reduce erosion. Boulders will be grouped in the stream to stabilize eroding banks. A slower stream flow and additional plantings will increase the amount of water that seeps down into the water table, providing moisture for soil, plants and trees, and reducing drought-like conditions. Less drought is good for habitat and property owners alike, she adds.
Plants help purify and clean the water table by taking up trace metals. By reducing the amount of clay that drains into the lake, sand will better be able to clean the water, too, reducing bacteria such as E. coli.
Investing in the Great Lakes
This project is part of the Great Lakes Restoration Initiative, a multi-million-dollar effort spearheaded by President Obama, which represents the largest investment in the Great Lakes in two decades. Partnering in this effort are the PDHP and the Gary Borger chapter of Trout Unlimited (GBTU). For the better part of a year, members of the GBTU chapter worked with the PDHP and community volunteers to monitor ravine water conditions, in the hope of restoring lost fish habitat.
With a $200,000 grant from the U.S. Environmental Protection Agency, work began in earnest this past winter. Knee-deep in snow and ice, staff and volunteers from the PDHP were at the mouth of the stream, taking baseline measurements of water conditions in order to evaluate the success of this pilot project. They tested such qualities as temperature, pH and conductivity by inserting instruments into pools of cold, running water.
“Work should be completed in time for spring runs of fish,” says Stefanie Nagelbach of Shabica & Associates, Inc., the sustainable coastal engineering firm that designed the project. V3 Companies, an environmentally focused construction contractor, is doing much of the restoration.
For more information, contact Rebecca Grill, Natural Areas Manager at [email protected].
Gail Goldberger is a communications professional and writer living in Chicago. Her work spans health care, human services, ecology, nature and the environment.