Shooter Ditch Sedimentation Project
Coffee Creek Watershed Conservancy, Inc
Basin Program Funds:
Shooter Ditch is largely responsible for undesirable levels of sediment loading into Coffee Creek. The sub watershed, roughly 450 acres of drainage, consists of agricultural and residential land-use practices which affect control of non point pollution in the area.
The Coffee Creek watershed covers approximately fifteen square miles. Within the watershed, the Coffee Creek Watershed Conservancy, Inc. (CCWC) now holds title to a 167-acre preserve that includes the stream corridor and adjacent woodland, prairie and fen communities. CCWC is also involved with the Town of Chesterton and adjoining property owners to proactively and holistically restore, enhance, and protect the watershed, its natural communities and overall water quality.
Shooter Ditch is located on the southern end of the preserve. Although it is the smallest sub watershed of Coffee Creek, it contributes large and ecologically detrimental amounts of sediment load. Shooter Ditch cuts through what was historically a large wetland complex and has become a priority for restoration efforts and nonpoint source pollution reduction for the CCWC.
Subwatershed modeling using the U.S. Environmental Protection Agency's Spreadsheet Tool for Estimation of Pollutant
(STEPL) version 2.0, indicated that the Shooter Ditch subwatershed delivers the second highest load of sediment to its respective creek of the four major subwatersheds in the Coffee Creek watershed despite being the smallest of the four subwatersheds. On a per acre basis, the Shooter Ditch subwatershed actually contributes the greatest amount of sediment of the four subwatersheds. Collectively, the water chemistry, biological, and modeling data suggest Shooter Ditch has a high potential for contributing sediment and sediment-attached pollutants to the Coffee Creek mainstream. Water chemistry sampling measurements of total suspended solids collected in Shooter Ditch during the growing season, exhibited the highest total suspended solids concentrations all of samples collected. The July sample possessed a total suspended solids concentration of 88 mg/L, well above levels that begin to impair biotic integrity. The benthic community lacked diversity and was dominated by sediment tolerant individuals, while no members of sediment sensitive taxa were observed during sampling.
A hydraulic and feasibility study was conducted to assess the effects of adjusted water levels on upstream property owners. There will also be negotiation and outreach efforts with adjacent property owners. The CCWC is currently seeking to allocate funds to procure and levitate easements rights and/or land acquisition on the upper watershed portions of Shooter Ditch.
A water control/weir structure will be installed at the downstream end of the property within Shooter Ditch. The area is currently a stagnant, deeply cut ditch. Raising water levels in the ditch will allow water to flow out into the adjacent land causing sediment to be dropped within the ditch itself and in the adjacent wetland. Additional filtering will occur as water flows through the restored wetland. The wetland will be planted with a host of native wetland plant species to improve wetland development.
A hydrological and feasibility study was completed in December 2003. The study assessed the effects of adjusted water levels on upstream property owners, as well as provided construction and engineering designs for restoration implementation. Negotiations were made with potentially affected property owners in 2003, and the purchase of conservation easement rights were finalized in January 2004.
A water control/weir structure, sediment trap and spillway were constructed at the specified elevations on the downstream end of the Shooter Ditch property, as determined by the hydrological analysis. An earthen plug was also constructed on a ditch along the eastern boundary of the site, which effectively intercepted runoff from Interstate 80.
Approximately 30 acres have been seeded and plugged with a host of native grasses, sedges and forbs and approximately 6 acres of native trees and shrubs were installed. Tree species include red maple, sycamore, button bush, red osier dogwood, river birch, pin oak and swamp white oak. The spillway and outlet feature was regraded to better accommodate 100-year rain events, which occurred in winter 2005. Post construction hydrology monitoring occurred in the spring and summer of 2004, as well as the spring of 2005.
The goal was to create a historic hydrological regime which included elements of surface and subsurface flow, thereby creating a more functional wetland complex. Raising water levels in the ditch has allowed water to flow out into the adjacent land. Sediment has been dropped within the ditch itself, near the ditch in the adjacent restored wetland and the sediment trap. Approximately 30 acres have been created and enhanced due to the recent restoration efforts. Annual soil savings are expected to exceed the anticipated goal of 412.18 tons per year. Savings per year of phosphorus and nitrogen are expected to exceed the goals of 4121.8 lbs and 824.36 lbs, respectively. After the 15 year life expectancy of the project, soil savings will exceed 6182.7 tons, phosphorus savings will exceed 61,287 lbs, and nitrogen savings will exceed 12,365.4 lbs.
Other benefits associated with the project include improved wildlife habitat in open water which has enhanced recreational use. The restoration has also decreased ecosystem fragmentation by connecting critical habitat of the Coffee Creek floodplain to the wetland communities of the upper watershed portion of Shooter Ditch. A working relationship was also established between regulatory agencies, private property owners, and the Coffee Creek Watershed Conservancy, Inc. The restoration received much recognition in the local environmental community with tours and several Power Point presentations given since the inception of the project.
Contact: Mr. Steve Barker, 219-926-1842