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Background on the LLCT Project
The Little Lake Cleanup Team project is aimed at lowering the PCB concentration in sediment in Little Lake Butte des Morts (LLBDM), thus reducing fish exposure to PCBs.
This effort is overseen by the Wisconsin Department of Natural Resources (WDNR) and the U.S. Environmental Protection Agency (EPA) and is being done under a settlement between those regulatory agencies and WTM I Company (former Wisconsin Tissue Mills in Menasha) and P.H. Glatfelter Company (former owner of the Bergstrom Mill in Neenah). The original Consent Decree was reached in 2003 and an amended Consent Decree, regarding the final phase of the project, was reached in 2008.
Prior to the implementation of the work, the two companies formed GW Partners, LLC to facilitate joint performance of the remedial activities. The Little Lake Cleanup Team (LLCT) consists of GW Partners, LLC and its contractors. J.F. Brennan, with headquarters in LaCrosse, Wis., serves as the General Contractor.
The work in this uppermost section of the river is the first major phase in the cleanup of the entire Lower Fox River, which stretches approximately 39 miles from Lake Winnebago to the mouth of Green Bay in Lake Michigan. It involves both dredging and the placement of sand cover and armored caps to reduce the level of PCBs in the lake sediment. That work began in 2004 with a focus on hydraulically dredging the targeted sediments from the lake bottom. This process employed sophisticated GPS-guided dredges, often two operating 24-hours-a-day, six-days-a-week during the spring, summer and fall months during the previous years.
The sediment that was dredged – or vacuumed – from the lake bottom was pumped from the in-water equipment via floating pipelines to the project’s shoreline staging area. At this staging area, the sediment, through a series of steps, was de-watered. Once dried, it was hauled to an approved landfill site for disposal. The water that was removed during the de-watering phase was treated at the on-site water treatment plant, and then returned to the lake.
Dredging efforts through June 2008 removed approximately 370,000 cubic yards of PCB-impacted sediment. Dredging by the LLCT was completed in mid-2008 and the last of the dredged sediment is expected to dry and be disposed by early 2009.
In June 2008, the placement of sand cover and armored caps (sand and gravel) to address the remaining targeted PCB-impacted sediment began. With this process, sand and/or sand and gravel is pumped from a shoreline staging area through floating pipelines to in-water equipment, which also use GPS systems, to evenly distribute (spread) the materials over the desired locations on the river bottom.
In an effort to aid and improve the efficiency of placing the material, the addition of a second staging area will occur in late 2008. That staging area is located on land leased from Wild Ones Natural Landscapers, a not-for-profit environmental education and advocacy organization. The lease of this property, which is approximately 1.5 miles north of the original staging area, allows for the LLCT to be closer to the areas being remediated at this latter stage of the project. The main use of the property will be to serve as the base for sand and gravel placement activities in the northern sections of LLBDM. The LLCT’s water treatment plant, dewatering pad, offices and observation deck will remain at the primary staging area. Also, as mentioned previously, all dredging operations have been completed and no contaminated sediment will be processed at this second staging area site. The second staging area’s proposed layout during operations and the final site layout are both shown in the figures below. These figures show the perimeter of the land disturbance and nearby water resources.
The area of property in the lease that will be disturbed is approximately 1.9 acres. The top 8 to 12 inches of the topsoil will be scraped and stored in a stockpile at the southern edge of the leased property to help buffer operational sounds from the staging area. The stockpiles will be seeded to reduce erosion. An engineered fabric will be placed on top of the bare soil in the scraped area, which will then be covered by eight to 12 inches of ¾-inch diameter crushed stone. There is one existing gravel driveway on the site, which is approximately 15 feet wide. This roadway will be expanded to be approximately 60 feet wide and an additional construction entrance will be created approximately 100 feet to the north. These two access points to the site will allow for trucks to enter and exit through two separate construction roadways to increase the efficiency and safety of the sand and gravel deliveries.
During operations, sand and gravel will be stockpiled at the site. There will be a separate operation for each material. When ready to be placed, the materials will be loaded, via a front-end loader, into a hopper that will drop the materials into a tank where they will be mixed with water to form a slurry. This slurry will then be pumped from the staging area to a barge where the water will be removed. The sand and/or gravel will then be placed over the pre-determined areas as part of the sand cover or armored caps. The material placement piping will cross adjacent properties and the wetlands area next to LLBDM prior to extending into Lake. That piping is made from High Density Polyethylene (HDPE or hard plastic) materials fuse welded together to prevent leaks and it will be removed at the end of the placement activities.
The use of the second staging area is planned for the duration of the project’s in-water remedial efforts. At the completion of these activities, the majority of the crushed stone and the engineered fabric will be removed, the subsoil that was under the gravel will be "ripped" to loosen the soil if needed, and the stockpiled topsoil will be spread back over the site. The Wild Ones organization and the DNR will be included in the post-construction restoration activities.
A portion of the gravel pad will remain as a parking area near the current Wild Ones office building. The anticipated final site layout is shown in Diagram A, however, the size and location of the gravel pad that will remain for the Wild Ones Parking lot will be decided before restoration of the site begins.
The construction activities at the site began August 14th with the fusing of pipe. Earthmoving activities (scraping of the topsoil, gravel placement, installation of the sand and gravel stockpile) will begin the week of August 25th, after the erosion control work (installation of silt fence and hay bales) has been completed. Actual placement of sand and gravel is scheduled to begin during the second or third week of September and go through October, depending on weather. Placement operations will resume in the spring of 2009 and continue until completion, which is anticipated to be early to mid-summer. At that time, the project’s in-water activities will be complete and site restoration will begin.
Throughout the LLCT project, the safety of neighbors, lake users and everyone involved has been a top priority. As such the project has an extensive above water marking system for the team’s pipeline, which floats above and below the water surface. These markers have been, and will continue to be, used throughout the remainder of the project when the placement of armored caps and sand cover is occurring. Additionally, the LLCT has made safety presentations to boating groups, posted safety marker information at boat docks and shared similar information with local registered boaters, neighbors, bait shops and marinas.
For more information on the LLCT project and its efforts on Little Lake Butte des Morts, visit the LLCT observation located at 1475 North Lake Street, or visit the LLCT web site at www.littlelakecleanup.com.
Wild Ones: Native Plants, Natural Landscapes
2285 West Butte des Morts Beach Road, Neenah, Wisconsin 54956-1008