CARIBOU, Maine — The severely damaged River Road may not be fixed this year, as engineers now need to conduct additional surveys to determine why new cracks are forming east and south of the portion originally impacted in 2018.
Public Works Director Dave Ouellette presented the findings of engineering firm Dubois & King during a city council workshop on April 29, exactly one year after city officials first shut down the road.
City officials temporarily closed the road in 2018 and bought properties along the damaged portion to relocate affected families. They reopened the roadway to one-lane traffic last November after public works crews filled in the sunken part of the road and added jersey barriers.
DuBois & King last fall presented city officials with four options to fix the road, and councilors chose the least expensive option, which involves moving the road east, further away from the river, and demolishing the homes on the road for $1.2 million.
City officials had not yet put the project out to bid, however, when new cracks appeared this spring in different areas of the road.
Ouellette told councilors on April 29 that he has been traveling to the site twice a day and has not noticed any additional damage since he informed them about the new cracks the week before. However, he said the new cracks on the east side of the road will pose a serious threat if the city chooses to move the road east, away from the river.
Additional damage, sinking, and cracks to the River Road in Caribou may lead city officials to shut down the roadway to traffic once again. New cracks on the east side of the road also could delay the process of fixing the road, which was originally planned for this summer.
(Chris Bouchard)
“I don’t have an engineering degree,” he said, “but I can tell you that you cannot put a new road there without doing something about that crack.”
Ouellette said a representative of Dubois & King revisited the area in the past week and recommended a multi-step plan moving forward. That plan includes continuing with the start of the original option, which involves advertising for bids to demolish the three homes purchased by the city. The demolition work would include asbestos abatement and cleaning up of the sites to remove large debris, abandoned vehicles, and metal scraps.
In another step, the engineering firm would submit another proposal and fee to the city to conduct a boundary survey of the affected area and a more “extensive geo-technical exploration to include the development of a slope stability model.” That should help the engineers determine the “type, shape, and mode of failure” of the roadway, Ouellette said.
To do this, they will document a 10 to 20 year history of the road, monitor wells, and conduct deeper borings of the road at the closed off portion in addition to the new cracks both east and south of the portion damaged last year.
Their final step is to meet with city officials to review their findings and present new recommendations moving forward.
In terms of additional costs, Ouellette said he was told the surveying could cost the city either an additional $4,000 or a total of $24,000 depending on the severity of damage on the road.
The councilors did not take any immediate action, but if they approve the $4,000 in the near future, the firm will first perform a supplemental site visit which will include observations, measurements, and photographs of nearby drainage features. The firm would then use existing soil boring data to determine the mode of failure and present the results of a slope stability model to the city.
If the results are still inconclusive, the firm will need to conduct a far more in-depth analysis including three or four additional soil borings at approximately 50 feet. This additional work would cost the city another $20,000.
Mayor Mark Goughan suggested a potential short term fix, such as adding more fill, which would allow the city to keep the road open for residents while the firm conducts additional surveys and determines a long-term solution. The public works director said he would look into the mayor’s suggestions and present a cost estimate during a future meeting.
“If the road does not get any worse than it is,” said Ouellette, “then we don’t have to do anything. It’s currently passable.”
Goughan said he will speak to the city manager, who was not present during the April 29 workshop, and possibly call for another City Council meeting if necessary.
