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Converting a degraded quarry into a community asset
Ted Gray, P.E., CFM, CPESC
Engineer/Eco-Hydrologist Living Waters Consultants, Inc. Burr Ridge, Illinois
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he Jelke Creek Bird Sanctuary is a 239-acre area located in the Village of Sleepy Hollow, Kane County, Illinois. The site was purchased by Dundee Township in 2000. The acquired open space is bordered by 2,000 feet of Jelke Creek to the west, and residential subdivisions in other areas. Jelke Creek contains several desirable fish species as well as a variety of freshwater mussels. However, the value of Jelke Creek and the newly acquired Bird Sanctuary were compromised by historic aggregate mining activities. Approximately 120 acres or 50% of the project site had been disturbed and degraded by quarry activities. Moderately eroding slopes occurred along approximately 4,300 linear feet of the project perimeter. Typical conditions included 2:1 (H:V) or steeper unvegetated areas with heights extending to 20 feet. Sheet, rill, and/or gully erosion was common throughout the area. Soil-stabilizing vegetative cover was lacking due to a lack of organic matrix in the topsoil.
Quarrying disturbance included removal of topsoil, excavation of aggregate resources, and truck hauling. Unstabilized spoil piles of sand and gravel were common. Moderately eroded slopes ranged up to 20 feet in height. During flood events, stormwater runoff from the site contributed to pollution impacts at downstream Jelke Creek.
Three degraded onsite ponds contained over 2,000 linear feet of eroding banks. Despite permeable soils, due to disturbance and compaction, silt-laden runoff would discharge through the gated south entrance toward Jelke Creek during flood events. Water quality impacts included siltation, sedimentation, nutrient enrichment, and habitat degradation extended downstream to Jelke Creek.
Project Goals
Primary goals of Dundee Township for the Jelke Reclamation Project included improving water quality and reducing flooding from the degraded site. Project engineers determined this could be accomplished by retaining as much rainwater onsite as practicable through storage, infiltration and retention. Reducing offsite runoff would reduce the discharge of pollution into Jelke Creek, increase infiltration, and increase groundwater recharge. Groundwater recharge could help to protect regional groundwater aquifers as well as stream hydrology and ecology. Converting the eroding site into stabilized areas with deep-rooted native vegetation was considered essential to accomplish project goals. In addition, Dundee Township sought to improve recreational opportunities for the community.
Final Engineering and Construction
Final engineering included the application of environmentally sound restoration engineering techniques within the context of a comprehensive site evaluation. Living Waters Consultants was hired to provide stormwater design, final engineering plans, ecological design, permitting, bidding assistance, construction observation, grant acquisition assistance, and ongoing maintenance and monitoring inspections. The lowest qualified bidding contractor, G.A. Blocker, Inc., was well-suited to large-scale, earth-moving projects.
Project Summary
Best Management Practices (BMPs) installed over 120 acres of degraded Project Area included the following:
• Conversion of 40 acres of eroding berms and stockpiles into stable slopes supporting native plantings; • Seven wetland filtration basins totaling 18.2 acres in area; • Conversion of one existing pond into a naturalized detention basin 0.5 acres in area; • Eight biofiltration swales totaling 3,670 linear feet; • Eight terraced swales over 4,000 linear feet in combined flow path length; • Forty-nine rock checks; • Five sediment forebays; • Over 875 linear feet of natural log toe and/or log habitat structures; • 111 acres of native plant seeding; • 3.6 miles of walking trails.
After construction, wetland filtration basins responded with extensive growth of native plant species.
Approximately 260,000 cubic yards of earthwork was applied over approximately 84 acres of area. Exposed and eroded substrate soils were regraded to stable slopes, recreational areas, or converted into best management practices. Topsoil stockpiles around the perimeter were respread over graded areas. Native plant species were selected which were relatively tolerant of the site’s droughty conditions and poor soil structure. Erosion blanket was installed around proposed basin shoreline areas. Straw mulch was hydroseeded in sloped areas to provide temporary site stabilization. In areas where concentrated flow could occur, rock checks were installed. Previously unvegetated berms, stockpile areas, and spoil piles were converted into stable slopes vegetated with deeprooted native plantings.
Seven wetland filtration basins were constructed with a total area of 18.2 acres. The wetland filtration basins ranged from 0.5 acres to 6.9 acres in area. Eight biofiltration swales totaling 3,670 linear feet were constructed along impervious surfaces such as the 30-stall parking lot or the entrance road, or along adjacent hillslope areas. Over 111.4 acres of native plant seeding was installed. Native plant seed mixes included shoreline, mesic prairie, dry prairie, emergent wetland, biofiltration swale, and mowed trail lists. Over 54,000 native plant plugs or tubers were installed in 2010. Over 86 acres of the project site now retain and infiltrate runoff from the sub-watershed through the 100-year, 24-hour rainfall recurrence interval. Flood control, water quality and ecological benefits include retention and filtration of runoff by wetlands, native plants, bioswales, and onsite aggregate soils, long-term site stabilization, habitat diversity, species recovery, improved site aesthetics, and protection of downstream Jelke Creek and the Fox River basin. Native habitats range from deep emergent wetland, to emergent areas, mesic shorelines, hillside seeps, upland dry prairie habitat, and woodland areas.
Project implementation provided a demonstration of environmentally sound stormwater management, conversion of a degraded facility into a restored area suitable for community recreation, enhanced ecological diversity, improved water quality, community education, and improved property values. Dundee Township acquired $897,735 in grant funding from the Illinois EPA (Section 319 Grant Program). In addition, over $400,000 in grant funding was received through the Illinois DNR Open Space Land Acquisition Fund. Construction costs were approximately $1.76M. The Jelke Creek Restoration Project was recently awarded the Stormwater Project of the Year by the Illinois Association for Floodplain and Stormwater Management.
Terraced wetlands were stabilized with erosion blanket after construction. These wetlands were constructed along previously eroding slide slopes over 20 feet tall in height. The eight terraced wetlands have a combined flow path of 4,000 linear feet. They filter, detain, and/or infiltrate runoff. Acknowledgements
We want to acknowledge the Illinois EPA (Section 319 Grant) and the Illinois DNR (OSLAD) for funding assistance. Chicago Metropolitan Agency for Planning provided grant administration. Living Waters Consultants provided engineering services, G.A. Blocker Grading, Inc. provided construction, and Applied Ecological Services provided native plant installation and maintenance. Project owner, Dundee Township, continues to manage and maintain the project site.
Ted Gray can be reached at (630) 261-1133 or TGray@ LivingWatersConsultants.com.
