1. Project Title: Urban Stream Stabilization Efforts Which Increase Instream Habitat While Controlling Bank Erosion
2. Contact
Bob Schacht
Illinois Environmental Protection Agency
South First Ave., Suite 600, Maywood, IL 60153 USA
Tel.: (708) 338-7900; FAX: (708) 338-7930
3. Agencies Involved
Illinois Environmental Protection Agency;
U.S. Environmental Protection Agency - Region V;
City of Waukegan;
Waukegan Park District;
Illinois Department of Conservation.
4. Restoration Goal
To demonstrate the effectiveness of stabilizing banks in urban parks along the Waukegan River (Waukegan, Illinois) in order to increase instream habitat and control bank erosion.
5. Project Type
Construction of "lunker structures" (i.e., large wooden boxes with both ends and the streamside open (Figure 1); wooden stringers and rebar are used to anchor the boxes into the bank and streambed) and use of "A-jacks" (i.e., interlocking concrete jacks which help stabilize stream banks during high intensity storms (Figure 2)); dense root systems of willows, dogwood, and grasses will then intertwine throughout the "A-jacks" and provide additional stability.
6. Background and Rationale
The City of Waukegan, State of Illinois and the Waukegan Park
District are demonstrating the effectiveness of vegetative stabilization
along the Waukegan River in urban parks where high velocity floodwaters
have damaged park bridges and city sewer lines. Under provisions
of Section 319 of the U.S. Clean Water Act, the Illinois Environmental
Protection Agency and U.S. Environmental Protection Agency have
funded innovative stream stabilization efforts which increase
instream habitat while controlling bank erosion. The urban restoration
techniques included construction of "lunker structures"
and use of "A-jacks". These structures have been placed
at three of the most erosive sites and have withstood the severe
flooding of 1993 (10.2 cm rain in one hour) without need of repairs.
7. Regulatory Considerations
Urban nonpoint source control requirements under Section 319 of the 1987 U.S. Clean Water Act.
8. Criteria
Considerable loss of gamefish habitat has occurred in most urban areas in the Great Lakes basin. The urban restoration techniques we used were chosen to resist high velocity runoff while increasing instream habitat for gamefish (e.g. bass, channel catfish, and salmon). These techniques provide habitat for gamefish by forming a stable undercut bank through the use of "lunker" structures.
9. Project Design
The project had three main components:
1) design and implement biotechnical stream restoration on three major bank erosion sites;
2) conduct two training workshops for Park District and city personnel, who performed hands-on installation of biotechnical bank protection techniques; and
3) develop stream and riparian maintenance procedures to ensure long-term stream restoration
10. Implementation
The project was undertaken during 1992 and 1993. A backhoe excavated a trench along the base of eroding banks. "Lunker" structures were placed along the entire reach of the eroding banks. Each "lunker" is held in position with nine 1.8 m lengths of 1.6 cm diameter rebar, which is driven into the streambed (see attached diagram). Initially, willow cuttings and small rootballs are placed into the trench behind the "lunker" structure with a geofabric mesh called fibredam. The fibredam reduces soil movement through the "lunker" structure while root systems are developing. Rip-rap of 25.4 cm average diameter and soil are then placed behind and above the "lunker" structure. The A-jacks and "lunker" structure were positioned below the streambed elevation so that any future instability resulting from channel degrading is minimized (see attached diagram). The bank is then sloped over the "lunker" structure and seeded. The seeded grasses are annual rye as the primary matrix and timothy as the secondary matrix. The final seed matrix depends upon the landowner - parks may choose a turf grass; in a nature preserve, the use of wet prairie grasses and flowers may be more appropriate. After initial growth of grasses and willows, additional rooted stock of red osier dogwood were planted near the water's edge. The root masses of the willow and dogwood minimize any soil loss above the "lunker" structure. Both excelsoir blankets and wood chips were utilized as mulch.
11. Degree of Environmental Intervention
Increase ability to withstand high velocity floodwaters in urban environments; minimize streambank erosion and nonpoint source pollutant inputs; enhance gamefish habitat; a hydrological investigation was used to target stream sites.
12. Cost and Resources
Labour and Materials $164 per meter of bank
Engineering Support $33 per meter - survey and permit application
On-site Training Program $1 000 (meeting, video and slides}
Subtotal $197 per meter of bank
Assessment (estimated):
Field Crew 10 days/season - data collection and flow measurements
Biologists 20 days/season - data collection and analysis
Other Chemistry analysis
13. Biological Assessment
Fish surveys and hydrological investigations were used as a basis for project design. The Illinois Environmental Protection Agency and the Illinois Department of Conservation are determining the degree of habitat enhancement and gamefish response in a long-term monitoring effort. Monitoring of the effectiveness of lunker structures in Franklin Creek State Park documented a 300% increase in smallmouth bass fry survival and a 50% increase in large bass residence.
14. Measures of Success
Stabilization of the study reaches has resulted in a reduction in erosion rates along the river and, consequently, a decrease in sediment loads delivered to Lake Michigan. Since erosion along the river has been reduced, further exposure of sanitary sewer lines and the associated damage has diminished. Flow velocities in the river have been decreased sufficiently by the establishment of vegetation to allow sediment to be deposited within the channel.
Success Rating: 4+
15. Key References
Office of Water Quality Management, Illinois State Water Survey. 1994. Waukegan River Restoration in urban Parks. Land and Water. Vol. 38 (5): 33-36.
Correct citation for this contribution:
Schacht, B. 1995. Urban stream stabilization efforts which increase instream habitat while controlling bank erosion, p. 149-153. In J.R.M. Kelso and J.H. Hartig [editors]. Methods of modifying habitat to benefit the Great Lakes ecosystem. CISTI (Can. Inst. Sci. Tech. Inf.) Occas. Pap. No. 1.