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Delavan Lake dredging project scheduled to start in mid-June

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ANN MARIE AMES
May 17, 2011
— It’s been a moving target for years, but the third part in a series of Delavan Lake restoration projects is just weeks away.

Dredging is expected to start in mid-June on a 3,000-foot section of the Delavan Lake Inlet, a 210-acre wetland that filters topsoil, fertilizer and sediment from the water that flows into the lake.


“The simplest analogy is that we’ve got this great big filter, and it’s clogged,” Delavan Town Board Chairman Ryan Simons said about the need for the dredging project.


The lake’s watershed is 26,000 acres, and the inlet drains about half of the watershed, according to the Wisconsin Department of Natural Resource’s environmental assessment of the project. About 60 percent of the phosphorous in the lake enters through the inlet, Simons has said.


The lake itself is 2,072 acres and is both fed and drained by Jackson Creek. The creek is a tributary of Turtle Creek, DNR documents state.


The plan is to remove 45,000 cubic yards of sediment from the inlet and pump it through a pipe 900 feet to an area behind Town of Delavan Fire Station No. 1 on Town Hall Road.


There, the sediment will be dewatered.


The water, once it’s been filtered, will go back into the lake. Water and soil tests already have been taken for this purpose and will be done again before the water is returned to Delavan Lake, Simons said.


The sediment, once it’s dry—or at least mostly dry—will be landfilled, Simons said.


The moisture level is the final piece to the project cost, Simons said. More moisture equals more trucks needed to haul away the sediment, he said.


“All parties are trying to make sure we can look out and try to have a plan,” Simons said. “What it’s going to be is on a per truck basis. While we have projections, we don’t know exactly what the moisture content is going to be.”


The town board March 15 unanimously approved a contract with JND Thomas, a California company, for $1.46 million, according to town documents. That was the fourth round in an attempt to find a bid that met the $1.04 million preliminary engineering bid.


In four rounds, the town opened a total of eight bids. The prices ranged from a low of $1.46 million to a high of $3.29 million, according to town documents.


The inlet project follows two recent projects. They were:


? The removal of 3,000 cubic yards of sediment from Brown’s Channel, a small tributary. The project was completed in winter 2006.


? Construction of the Mound Road sedimentation ponds, a 140-acre wetland with two man-made sedimentation ponds. The 4- to 5-foot-deep ponds were constructed in 1992. By 2002, the ponds were more than 40 percent filled with sediment and no longer functional. To renew the ponds, they needed to be dredged and deepened to 10 feet. The project was wrapped up in 2009.



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