A new inspection report has flagged the retaining wall along the Boardman River in the 100-block alley of Front Street downtown as being in “serious” condition, requiring both short and long-term fixes to stabilize it. Those city repairs could be coordinated with a larger riverwalk project being considered for the area by the Traverse City Downtown Development Authority (DDA), including the replacement of the pedestrian bridge, placemaking improvements, and habitat and stormwater upgrades.

DDA board members will discuss the project area at their 9am meeting Friday, with city commissioners to review the inspection report at an October 12 study session. City engineering has been working with consultant Wade Trim to evaluate the retaining wall along the river between Union and Cass streets for several months. The aging structure, which is a cantilevered reinforced concrete wall with timber piles that date back to 1931, has been a known problem for years. The city relocated a sewer trunkline away from the wall to the middle of the alley because of fears of a potential failure, which proved prescient when a major sinkhole formed during this year’s April flooding, exposing the abandoned line.

Crews addressed that sinkhole, but new sinkholes were observed directly west of the repair site in August – “indicating that the wall continues to be unstable due to undermining of the footing,” according to Wade Trim. The company performed both field and underwater inspections in May and found the retaining wall is “severely deteriorated and unstable,” with “extensive scour and undermining of the footing.” On a scale of excellent, good, fair, serious, and critical, the wall’s overall condition is currently serious, Wade Trim found.  

City Engineer Anne Pagano says that “although the structure is not currently considered critical, a short-term repair is recommended to help protect the wall until permanent stabilization can be implemented, which is currently anticipated to be approximately two years before construction.” The short-term repair is still being determined but would likely be similar to the April fix, in which lightweight concrete was placed “behind the existing wall to reduce erosion and limit further undermining beneath the wall,” according to Pagano.

That repair is estimated at $252,000 plus engineering costs. A longer-term solution “incorporating sheet piling and bank naturalization” is estimated at $2.1 million in today’s dollars, not including design costs, Pagano says. Staff plan to seek commission input at the October 12 meeting on both the short and long-term repairs. In the meantime, two DDA projects – the redesign of the riverwalk area around the pedestrian bridge leading to the farmers market and grant-funded river habitat improvements – offer “a valuable opportunity to coordinate the improvements and develop an integrated approach to the riverfront,” according to Pagano.

“Coordinating the projects during the design phase will help to improve project efficiency, minimize potential conflicts during construction, enhance the river interface, and help protect and improve aquatic and riverbank habitat,” she wrote in a memo.

DDA Executive Director Harry Burkholder agrees with that approach. Staff Friday will “take this opportunity to inform the DDA board about all of the moving parts of the project and look at this area holistically,” he tells The Ticker. The board in January approved the schematic design by INFORM studio for a proposed $5.7 million reconstruction of the riverwalk area, a project that would include a remodeled J. Smith Walkway, new pedestrian amenities in the adjacent alley and parking lot, and a new pedestrian bridge. The existing bridge is deteriorating and reaching the end of its usual lifespan.

The next step was for the board to authorize completing construction drawings, which would get the project shovel-ready. However, board members Friday are now expected simply to receive a project update and discuss options. They’ll then wait to hear commission input in October before deciding how to proceed. Voters will also weigh in this November on whether to extend downtown’s tax increment financing (TIF) 97 plan, renamed the Infrastructure First TIF plan, which would have a major impact on available funding for the riverfront.

If the plan is rejected by voters, the DDA could still use existing TIF 97 funds to complete the construction drawings. “That gets us to a final design, under which the city or grants or other opportunities could fund the construction,” Burkholder says. “The DDA is still part of that conversation...but those decisions have a lot of factors that go into them should TIF not be approved.”

Cost-sharing with the city is possible in areas of project overlap, such as the retaining wall, stormwater infrastructure, and habitat improvements, Burkholder says. The DDA also has grant funding from the National Oceanic and Atmosphere Administration (NOAA) in partnership with the Grand Traverse Band of Ottawa and Chippewa Indians to complete in-stream habitat treatments along the Boardman. One of the grant’s focus areas is the 100-block alley.

Burkholder says staff are “exploring whether there may be an opportunity to coordinate the two efforts and maximize the benefit of any work that ultimately occurs in this area.” He notes the new riverwalk design was the result of “five years of community conversation about how the city and downtown could orient more” toward the Boardman, with the entities now able to have a coordinated discussion “about the entire scope of this block.”