Erosion appears to have cut initial estimates in half for how much PCB-contaminated soil needs to be removed from the Kalamazoo River near Otsego.
On-scene coordinator Paul Ruesch, with the U.S. Environmental Protection Agency, told press during a tour Monday, April 24, that he estimates roughly 60,000 cubic yards of sediment will be removed during the project, expected to wrap up next year.
“When we first started this project (last fall), our estimates were about 120,000 yards were to be removed, based on testing done 10, 15, 20 years ago,” Ruesch said. He said experience with the first section of the project and the extensive sampling in the riverbed and bank last summer showed there will likely be less removal necessary.
“Main reason, a lot of it has mobilized,” he said, explaining that erosion drew the soil into the river, stirring contamination back into the water.
Nowhere is it more apparent than the area now being remediated, a stretch of 900 feet of river starting where it passes beneath M-89 just west of Otsego and heading downstream. Crews have prepared a staging area and a temporary road for work on the south side, a sharp bend in the river that takes the full force of the river flow.
Ruesch said, “Actually this was one of the main precursors to this project, with erosion along these banks dropping that contamination in the water and moving it downstream.”
The EPA project is a time critical removal action along a 1.7-mile length of the river between the Otsego Township dam and the M-89 bridge. The $25 million project is being funded by the companies that inherited the responsibility for the pollution.
Crews in the current stage will dig out contaminated sediment in the riverbed and the first 10 feet of the current riverbank, using GPS-guided controls to scoop out sediment to precise depths. As with the first section of work last year, daily soil samples will be taken from wherever sediment is removed to be tested overnight. The results will inform whether or not any further digging is required.
Sediment is hauled to a holding pen, sealed to divert any water to an onsite water treatment facility, where it is then sorted by level of concentration of PCB.
To date, the project has removed 7,224.55 tons of sediment. Only 103.91 tons of that amount has had a concentration of PCB over 50 parts per million and been hauled to a special EPA landfill on the other side of the state. The rest has been put in Grand Rapids-area landfill.
The ultimate goal of the cleanup is to remove sediment that has more than 5 parts per million of PCB.
Ruesch said the erosion happening in recent years was due to the contemporary water level. When the hydroelectric dam was in place, the water level was up and over the current banks.
Plans no longer call for a barge to be in the river to support excavation; it is being done from the bank with an excavator with a 60-foot arm.
Dam
With all of the activity underway upstream, it’s easy to forget one of the main goals of the project: removing the dam in Otsego Township.
It has been decades since the hydroelectric dam was in operation. When it became clear the structure was dangerously close to failing, its power house was removed and replaced with a temporary water control structure built by the Michigan Department of Natural Resources using several grants and several million dollars from the settlement the DNR reached with Enbridge Energy after its pipeline spilled oil into the river in 2010.
DNR dam manager Mark Mills said design work was underway to determine how the structures will be removed and natural banks be restored.
“The soon-to-be-former dam. That feels good to say,” Mills said. “We’re working on the plans for removing both the water control structure and the spillway. A pathway for fish is important.”
The river is expected to remain closed for public use through the end of the project—estimated at March 2018—from just past the dam upstream to before the M-89 bridge.
At every stage of the project, Mills said contractors, the EPA and the Department of Environmental Quality were coordinating to take into account future public access to the river. That was on display at the site of the first area of the project, completed last year. Where there had been a staging area along Jefferson Road near Pine Creek for the heavy equipment, sediment storage and water treatment is now a gravel parking area. Grass is starting to sprout on the riverbank along with buds forming on the native brush and trees planted along the bank.
The white tubes on the trees protect them from wildlife while they take root and get established. The project will monitor the area for a year after completion to ensure everything takes hold.
Work
With an average of 20 trucks passing into or out of the current staging area and other access points, the on-site contractor stressed the need for the public to drive past the site more cautiously and heed the signage posted by the state.
Work is ongoing between 7 a.m. and 6 p.m. Monday through Saturday. Crews time truck traffic to avoid the periods of traffic congestion due to morning and afternoon commuters.
The project is currently on schedule; Ruesch said crews will be at the current spot for another two months
“This area’s our most challenging spot,” he said. “The force of the river makes for difficult working conditions.
Crews will create a new riverbank as a barrier to protect where they are excavating, using stones and giant sandbags. They will also reshape the riverbed to redirect the highest velocity flow away from the bank with formations called J-Hooks.
Ruesch said, “They are buried rock that will slow down the energy of the river. They will be permanent; you won’t see them. You’ll be able to kayak and canoe right over them.”
The project will then move further downstream; the lion’s share of the overall the approximately 3,000 feet of the project will be completed this year.
The ultimate goal of the project is to remove the dam and replace riverbanks that contain PCB, a carcinogenic byproduct of the paper manufacturing process that was dumped into the river. As parts of the riverbank erode, PCB-laden soil slips into the water, where it collects and concentrates in fish. Fish advisory signs posted throughout the Kalamazoo River warn against eating fish caught in the river.
Contact Ryan Lewis at rmlewis@allegannews.com or (269) 673-5534.
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