High water levels hinder pipeline construction projects in Caribou area

Posted Sept. 14, 2011, at 5:37 p.m.
Construction workers begin efforts Tuesday afternoon to drill from one bank to the other under the Little Madawaska River in Caribou on Tuesday afternoon.
Courtesy Natalie Bazine, Aroostook Republican & News
Construction workers begin efforts Tuesday afternoon to drill from one bank to the other under the Little Madawaska River in Caribou on Tuesday afternoon.

CARIBOU, Maine — High water levels of the Little Madawaska River have hindered two pipeline construction projects, both literally a stone’s throw from completion.

Standing on the bank off Grimes Mill Road on Sept. 9, Mark Draper watched as water rushed downstream at 917 cubic feet per second — more than 800 cubic feet per second higher than normal based on a U.S. Geological Survey average for the last three years.

“Last year at this time you could walk across this river and not get your feet wet,” said Draper, solid waste director of the Tri-Community Landfill.

Tri-Community Landfill is 175 feet from completing a 2.3-mile pipeline project to connect the landfill to the Caribou Utilities District, where the landfill’s leachate — water that has come into contact with garbage — will be treated.

Until the pipeline is completed, Tri-Community employees will continue hauling the leachate to the CUD one 6,300-gallon truckload at a time.

As Draper explained, CUD didn’t have the capacity to accept Tri-Community’s leachate when the landfill was first built, and there wasn’t a feasible way to pipe the leachate to Fort Fairfield for treatment.

Now that Caribou has the capacity for the leachate, the pipeline will save Tri-Community employees roughly 1,000 trips a year hauling approximately 6 million gallons of leachate.

But nature seemed to have other plans for the project as record-setting precipitation this summer has caused the Little Madawaska River to swell and rage along. Workers with Soderberg Construction considered building a cofferdam to push river water to one side in order to lay two 6-inch pipes across the riverbed — one pipe for daily operations and the other as a backup. But the high, rushing water dampened that plan.

Instead, officials with Tri-Community and Soderberg opted to go with directional drilling under the river — essentially drilling down from one bank, under the river, and over to the opposite bank.

Subcontractors with Enterprise Trenchless Technologies Inc. of Lisbon Falls were on-site Tuesday afternoon for the directional drilling under the river, which will allow the two ends of the pipeline finally to meet after a season of opposing each other from the banks of the Little Madawaska. The project is likely to be completed this week.

Expediting the weather-delayed project by drilling and essentially bypassing the river will cost an estimated $18,000. That cost will be split between the contractor and Tri-Community. The total projected cost of the leachate pipeline project is approximately $1.7 million, which includes engineering, easements for right of way, environmental permits and construction.

What Draper found most frustrating was that the rain not only delayed the project but also added to the amount of leachate that needed to be treated.

But Tri-Community Landfill isn’t the only entity that has been trying in vain to cross the Little Madawaska River this summer; just downstream, the Greater Limestone Water and Sewer District also is just shy of completing a pipeline project. That district is trying to connect to an existing Caribou Utilities District pipeline so its treated waste can reach the Aroostook River.

Limestone Water and Sewer Director Jim Leighton explained that directional drilling isn’t an option for that project because the pipe the district plans to run under the river has a diameter of 21 inches.

Like the Tri-Community project, efforts to build a cofferdam earlier this summer were a wash.

“So now we’re doing the waiting game,” Leighton said.

Since Sept. 6 and 7, when the river was rushing at more than 2,500 cubic feet per second — bearing in mind a gallon of water weighs just more than 8 pounds — the water level has been dropping steadily. At the beginning of this week, the river was “down” to 374 cubic feet per second. Waiting out the weather isn’t a problem for LWSC, as a few weeks’ delay won’t change the project’s cost.

Leighton is confident that the project will find a window this fall.

“This [pipeline under the river] will connect us to the Aroostook River, then it’s just a matter of turning a couple of valves and we’ll be able to start utilizing the pipeline,” Leighton said.

Leighton also pre-emptively clarified that while the Greater Limestone Water and Sewer District is connecting its pipeline with that of the Caribou Utilities District in order to reach the Aroostook River, all of Limestone’s wastewater still will be treated in Limestone — it’s not being transported to Caribou. Rather, LWSD is using the same diffuser pipe as CUD to discharge into the Aroostook River.

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