Officials recommend dredging if dam is retained
By Jason Arndt
Staff Writer
A recent study of Echo Lake uncovered a staggering amount of sediment, including phosphorous, which could cost the City of Burlington $2.5 million to remove the materials under a potential dredging project.
The study, which the Common Council approved in April, is part of the city’s long-term plan to address regulatory compliance issues with the Echo Lake dam, recreational degradation and phosphorous concerns.
Peter Riggs, Director of Public Works, discussed the matter with the Common Council during Tuesday’s Committee of the Whole meeting.
“This task order was issued in conjunction with another study that Ayres is performing for us and that is the spillway compliance alternative study related to a Wisconsin DNR requirement that our dam achieves certain spillway design standards,” the said. “The DNR provided that direction to the City of Burlington back in 2015, we have a compliance deadline of July 2025.”
Meanwhile, as for the Echo Lake study, which consisted of a hydrosurvey and sediment sampling, Riggs said the results did not include any commentary on dam modifications.
“It is merely an analysis on Echo Lake itself, the sedimentation and the characteristics of the sedimentation and then a proposal of a project or direction,” he said.
Ayres and Associates, which collected field data at Echo Lake on April 29, discovered an average lake depth between one and two feet.
Sediment samples were then sent in for laboratory analysis to identify phosphorous loading of the sediment or any possible contamination.
“Ayres approximated 280,000 cubic yards of sediment within that area. It is a pretty staggering amount,” Riggs said.
According to the findings, dredging to create a four-foot water depth would require removal of 115,000 cubic yards of material, which could cost at least $2.5 million.
“The project cost does not include any land acquisition, design, or project management costs that would be incurred, so that is just a rough project estimate at this point,” Riggs said.
To read the entire story, including reaction from residents who attended the meeting, see the July 8 edition of the Burlington Standard Press.
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