Little Lake Cleanup Staging Areas

Key areas for the Little Lake Cleanup project were our staging areas. 

Our primary staging area (or sediment processing area) was located just south of the Highway 10/441 bridge and east of N. Lake Street in the Town of Menasha.
The staging area was used primarily during the dredging, dewatering and hauling portions of the projects, which have been completed.

Beginning in 2008 and into 2009, our project primarily operated from the second staging area, located on Butte des Morts Beach Road. That staging area was used as our in-water work progressed north to minimize the amount of pipeline that was required on the lake.

See descriptions below for more detail on each staging area.

Staging Area 1 - N. Lake Street

At this site, the sediment, which had been vacuumed off the bottom of the Lake, was pumped from the dredge through a pipeline to this primary staging area. Polymers were added in the pipeline to the sediment and water mixture as it entered the dewatering pad. The polymers allowed the sediment to flocculate (stick together). When that mixture entered the two thickeners, which are large metal tanks, the heavier sediment settled to the bottom, while the water flowed to the dewatering pad and then to the water treatment plant. The sediment that collected at the bottom of the tanks was then pumped into large mesh geotextile tubes for further dewatering.

Once the sediment was dewatered, trucks hauled the sediment via Towmen Road to Highway 41 and out of the area for disposal at the Hickory Meadows Landfill. Each truck had a plastic liner, a sealed gate and was covered with special tarps to contain the sediment during transport in accordance with all federal and state regulations. The trucks were also washed and thoroughly inspected before leaving the area, and air quality monitoring was performed at the staging area as part of the WDNR and EPA oversight on the project.

This primary staging area was utilized for all dredging operations as well as the placement of cover and caps in the southern portion of the lake, both of which are now complete.

The last of the dewatered sediment was hauled from this site in January 2009.

The site is currently being restored and that work is expected to be complete in the early summer of 2010.


Staging Area 2 - Butte des Morts Beach Road

This staging area was added in late summer 2008 to provide a staging area closer to our late 2008 and 2009 in-water work. All of that in-water work occurred north of the Hwy. 10/441 bridge and the closer staging area was most efficient and helped with in-water safety by reducing the amount of pipeline that was required.

The LLCT leased approximately 2 acres of land for this staging area from Wild Ones Natural Landscapers, a not-for-profit environmental education and advocacy organization. The site housed some of the project's pumps and pipeline as well as sand and gravel supplies needed for the placement of sand cover and armored caps in northern Little Lake Butte des Morts. With dredging already completed, no contaminated sediment was processed or stored at the staging area.

Work to construct the second staging area was completed in the fall 2008 and included the following: the top 8 to 12 inches of the topsoil was 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 were seeded to reduce erosion; an engineered fabric was placed on top of the bare soil in the scraped area, which will then be covered by eight to 12 inches of -inch diameter crushed stone. Sand and gravel materials for the project were stored in this area.  Additionally, there was one existing gravel driveway on the Wild Ones site that was approximately 15 feet wide. The roadway was expanded to be approximately 60 feet wide and an additional construction entrance was created approximately 100 feet to the north. These two access points to the site allowed for trucks to enter and exit through two separate construction roadways increasing the efficiency and safety of the sand and gravel deliveries.

During operations, when sand and/or gravel was ready to be placed, the materials were loaded, via a front-end loader, into a hopper that dropped the materials into a tank where they are mixed with water to form a slurry. This slurry was then pumped from the staging area to a barge where the water was removed. The sand and/or gravel was then spread over the pre-determined areas as part of the sand cover or armored caps. The material placement piping crossed adjacent properties and the wetlands area adjacent to LLBDM prior to extending into the Lake. That piping was made from High Density Polyethylene (HDPE or hard plastic) materials fuse welded together to prevent leaks, and was removed at the end of the placement activities.

The second staging area was used for the duration of the project, which was completed in May 2009. Only a portion of the gravel pad remains as a parking area for the Wild Ones office building. The Wild Ones organization and the Wisconsin DNR were included in the post-construction restoration activities.



Following are a few photos that show the earlier construction of the dewatering pad and water treatment plant at Staging Area 1. Please click on any of the below images to enlarge.

 

Observation Deck


During active work, the Little Lake Cleanup Team welcomed people to visit its observation deck, which provided guests with informative signs detailing the project and safety information. 

We thank the many neighbors, environmental classes and other tour groups for their visits to the observation deck and for their interest in the project.

 

The observation deck, dewatering pad, machinery and other materials have since been removed allowing for the restoration of the staging area.
At the height of the cleanup project, visitors to the deck could get an up-close view of the geotextile tubes, which were used to drain water from the lake sediment. They could also observe the lined, gravel dewatering pad that held the tubes, collected the water and pumped it to the water treatment facility for treatment. Deck guests could also touch a sample of the mesh material that made up the geotextile tubes and the deck signage provided diagrams on the entire cleanup process and an overview of the project's safety markers that were to be followed when traveling on Little Lake Butte des Morts.

Please click on the image above for an enlarged view of the observation deck.
 

 

For more information on staging area operations, please click on any of the images below to enlarge.


Two thickeners, which are large metal tanks, aided in the process of separating the water and sediment prior to the sediment entering the geotextile bags. The thickeners were added to the dewatering process in 2006 and significantly helped speed up the dewatering process.
In this photo, sediment dewaters in geotextile tubes located in Staging Area 1.
Geotextile tubes were contained within a lined sediment dewatering pad.
The water treatment facility removed PCBs before returning clean water to lake.
This photo shows the water treatment facility at Staging Area 1.
In this photo, dewatered sediment is loaded into lined trailers for transport to a licensed landfill.