The retaining wall along a section of Kenduskeag Stream in downtown Bangor is starting to collapse into the stream, an urgent problem that will be costly for the city to repair.
The wall is located just west of Franklin Street, along the southern bank of the stream, and just north of the Bangor post office and Penobscot County Jail. It holds back both a sewer line and the walking path that follows the stream. Beyond that path is another retaining wall that props up the driveway out of the post office parking lot.
The estimated cost of the repair could range from $200,000 to more than $700,000, according to City Engineer John Theriault. He said the city is now evaluating what options there are for a fix, with the less expensive one being the installation of a new wall in front of the current one, and the more expensive solution requiring a total replacement of that section of wall.
The city has also considered installing rip rap next to the wall in the stream bed, which might have been the least expensive option, but Theriault said state and federal regulators probably would not permit that sort of fix.
Right now, some segments of the concrete wall have fallen out of place, likely as a result of deterioration from the brackish water that comes up the tidal Kenduskeag Stream.
“This definitely needs to be done,” Theriault said. “I’m hoping to get started this fall. If we don’t get it done and freezing weather sets in, it will play havoc with what’s left of the wall.”
The city has been planning to assess the stability of those retaining walls in recent years and has so far set aside $200,000 for any work, but Theriault said the city will now have to come up with the rest of funds promptly. The repair will require the approval of the Maine Department of Environmental Protection and U.S. Army Corps of Engineers, as well as a vote from the City Council.
Adding to the challenge is the placement of the 42-inch sewer main line behind the retaining wall and the fact that the Kenduskeag Stream is tidal, meaning that work would only be possible when the tide is lower.