Posted on May 9, 2016
By Lyn Jerde, Portage Daily Register
While the elevator shafts and steel framing of Columbia County’s under-construction administration building start to redefine the Portage skyline, another change, just as far-reaching, is scheduled to take place in Portage Canal.
Starting in about 2½ weeks, a dredge will pull from the canal’s murky waters more than a century of accumulated, contaminated sediment.
Columbia County’s canal-side building project wasn’t the impetus for the dredging. But the construction of a three-story administration building on the canal’s northwest side, and a two-story Health and Human Services building on the canal’s southeast side made the project more urgent.
It would be much harder to dredge the canal segment near East Edgewater and East Mullett streets after the new buildings are already up and open, said Bill Fitzpatrick, an engineer with the Wisconsin Department of Natural Resources Office of Great Lakes and Contaminated Sediment Unit.
But since the area is already a construction site, he said, now is the time.
“The buildings present the opportunity,” Fitzpatrick said, “and a whole lot of urgency.”
Fitzgerald attended Thursday’s meeting of the County Board’s Ad Hoc Building Committee, where the committee voted unanimously to endorse the DNR’s recommendation to hire Infrastructure Alternatives, Inc., based in Rockford, Michigan, to dredge the canal in the vicinity of the under-construction county buildings.
The Infrastructure Alternatives bid of $278,183 — for removing sediment from the canal with a cable-driven system — was the lowest responsible bid, according to Steve Klaven, senior project manager for J.H. Findorff and Son.
Three different companies submitted bids, Klaven said, and Infrastructure Alternatives submitted two proposals — the other entailing a different dredging method, at a cost of $370,000.
One of the bidders quoted a lower price than Infrastructure Alternatives, he said, but that company did not submit required information, like its safety record and qualifications for this type of project.
Dredging work is expected to begin the week of May 23, and it’s expected to take up to three weeks.
Here’s what’s going to happen, according to Fitzpatrick:
The dredging apparatus will go into the canal’s water and dig up the sediment that has accumulated at the bottom – sediment that he said is contaminated with lead, mercury and urban-industrial pollutants like oil.
The dredged material will be vacuum-pumped into semi-permeable containers called Geotubes (a brand name for a type of sludge dewatering bag).
The water that drains out of the Geotubes won’t be put back into the canal, but will instead be treated at Portage’s wastewater plant.
The sediment will be allowed to dry for about two weeks, then it will be hauled to a landfill. Originally, county officials had hoped to use the sediment as the base for the new paved parking lots near the buildings, but it’s not suitable for that purpose.
When the project is done, the canal — now about 2 feet deep because of all the sediment at the bottom — will be about 6 feet deep, Fitzpatrick said.
He added that the DNR is studying the possibility of dredging other areas of the canal in the future.
Columbia County Supervisor Kirk Konkel of Portage, chairman of the Ad Hoc Building Committee, said the dredging project has been shown to be a very effective partnership between the DNR, Columbia County and the city of Portage.
The DNR is paying most of the project’s costs, Konkel said. The county’s and city’s share of the costs will, for the most part, consist of in-kind services, such as the use of the city’s wastewater treatment system and the county’s staging and fencing of the construction area — which was done anyway for the building project.
Source: Portage Daily Register
