Posted on June 4, 2019
A Portage Canal improvement project that had seemed stagnant for years is moving forward, about 40 people learned Thursday at a public meeting.
City Engineer Aaron Jahncke told the group that a 3,600-foot segment of the canal, from Adams Street east to the Canadian Pacific Railroad tracks, will be dredged of about a century’s worth of sediment next year. And in 2021, a 10-foot-wide trail, for bicyclists and pedestrians, will be extended east along the canal’s south side.
Wisconsin Department of Natural Resources officials announced in late April the state has committed to participating in the project, at an estimated cost of $4.3 million — clearing the way for the city to use grant money for construction of the trail and a pedestrian bridge at the welded-shut Wisconsin River locks.
Although the canal will never again see shipping traffic or flow from the Wisconsin River due to concerns about invasive species entering the watershed, Jahncke said he’s confident the improvements will result in a cleaner and more inviting waterway.
He said at the outset, nobody’s going to “just fill the thing up.”
“First of all, it’s historical,” Jahncke said. “Second of all, it’s a waterway of the state. Third of all, it’s part of the city’s stormwater management system.”
Loads of dirt
Scott Inman, DNR water resources engineer, said this will be a much more massive dredging than the 2016 project from DeWitt Street to Adams Street, carried on in conjunction with the construction of Columbia County’s Administration Building, 112 E. Edgewater St., and Health and Human Services Building, 111 E. Mullett St.
He said during that project, 1,000 cubic yards of sediment were removed from a 600-foot segment of the canal.
This project will involve the removal of about 20,000 cubic yards of sediment, adding 2-4 feet to the water depth at the canal’s center, Inman said.
No one knows for sure exactly what contaminants lie at the canal’s bottom, Inman said.
But based on the history of the area, there is likely to be contamination from automotive-related industries that used to exist in the vicinity — and a fair amount of discarded junk, such as car and bike tires, children’s toys and other things people have tossed into the canal over the years.
Will it stink?
This prompted Portage Common Council member Dennis Nachreiner to ask a blunt question: “Will there be a stench?”
Probably, said Kim Powell, a consultant with Anchor QEA, who’s working with the DNR on the project.
The contaminated sediment will be transported to a “processing pad” that will be set up on DNR property near the railroad, where it will be placed in specially made containers, shaped something like giant bathtubs, to dry before it can be sent to a landfill.
Powell said it typically takes 3-5 days to dry the sediment and during that time there may be an odor of decaying material. But the project includes measures to minimize the smell, she said.
After the dredging, capping material will be placed at the canal’s bottom to minimize future contamination.
Project in progress
Chris Blum, an engineer with the city’s design consultant Short Elliott Hendrickson Inc., said the completion and approval of the required environmental report is expected to happen this year, in time to allow the dredging to start in 2020.
Inman said the dredging could take the better part of the warm-weather season in 2020 — and what kind of equipment will be used for it will depend on which contractor the DNR hires.
For the 2016 dredging, the DNR hired Infrastructure Alternatives of Rockford, Michigan, which used equipment on barges to dig sediment out of the canal — along with an assortment of boulders, building materials, tires, bicycles, shoes, socks and at least one scooter.
Barges could be used for the upcoming dredging, Inman said. Or some companies use amphibious equipment designed to move atop wetlands.
A pre-dredge assessment of the sediment, at the end of 2018, turned up some hints of what the dredgers might find, Inman said — including “urban garbage” like plastic bottles and automotive tires.
In 2021, after the dredging is done, the multi-use trail and bridge over the locks are expected to be constructed.
Blum said those amenities are designed to make the canal more accessible and attractive to people.
“It’s not that great now,” he said, “but it’s going to get better.”
Source: wiscnews.com
