Consultants To Deliver Final Report On Boardman River Wall
By Beth Milligan | Jan. 8, 2022
Traverse City commissioners will review a final report Monday from consulting firm SmithGroup on a compromised section of Boardman River retaining wall the firm was hired to evaluate in the 100 and 200 alley blocks of Front Street.
The report echoes many of the firm's preliminary findings in an earlier study of the area, which determined that a loss of soil due to continuous scouring and undermining of the wall footing by the river was creating safety risks along the river. Based on those findings, the city and Traverse City Downtown Development Authority (DDA) entered into a contract with SmithGroup to conduct a stabilization assessment for the south edge of the Boardman River between Union and Park streets. The assessment included hydraulic modeling under different "treatment" options to better understand potential impacts (up and downstream), permitting needs, and other possible land-use modifications.
In a summary of SmithGroup's final report, City Director of Municipal Utilities Art Krueger wrote to commissioners that "although there has not been any noticeable visual movement of the wall to date, the undermining of the wall footing upon which the existing 24-inch sanitary sewer main rests, puts the sewer at risk and it needs to be protected (or relocated). The footing and wall are supported by wooden piles, but they only provide vertical support to keep the wall and footing from settling. As a professional engineer, my opinion is that the lack of soil under the footing may cause the static condition of all the forces acting on the wall and footing to become unbalanced, which would allow the wall and footing to tilt or move."
If that were to occur, accoring to Krueger, "this movement could cause a catastrophic failure of the sewer main allowing raw sewage to discharge directly into the Boardman River." He concluded: "Therefore, it is critical to pursue the wall stabilization engineering design work in the 200 block as soon as possible." According to Krueger, the DDA recently met with property owners in the 100 and 200 blocks to discuss the project, as well as a request-for-proposals (RFP) for potential placemaking work in the area. Placemaking work could include the possible removal of part of the wall and some parking spaces to create a riverfront plaza with direct public access to the Boardman. RFP bids were received in late December, with the DDA planning to conduct interviews with firms this month.