Marshall Ave. bridge replacement begins

Temporary repairs of the Marshall Ave bridge in 2017.

Traffic detoured to Route 2


Observer staff

A long-awaited permanent replacement to the bridge that connects Williston and South Burlington over the Muddy Brook at Marshall Avenue is expected to be open by end of the year, but not before a five-month closure that detours traffic to Route 2 starting Monday.

Williston voters approved a $1 million bond for the project at Town Meeting Day in 2020. The town is sharing the estimated $2 million cost of the new bridge with South Burlington.

The bridge is being designed with more space for bikers and pedestrians to cross between the two municipalities.

Structural problems with the crossing were first exposed in the spring of 2017, when a metal culvert that takes the Muddy Brook under the bridge washed out under heavy rains. The culvert failure destabilized the bridge, and the connection was closed for several months until the two municipalities, working with the Vermont Agency of Transportation, installed a temporary bridge in August of that year.

About two years later, in a “Halloween Storm” in 2019 that dropped roughly 4 inches of rain on Chittenden County, the culvert was overwhelmed again, causing a closure of the temporary bridge that lasted through the end of 2019.

By the beginning of 2020, crews with Engineers Construction were able to stabilize the embankments of the brook and reopen the temporary bridge. Both municipalities have been working on an expedited timeline since then to secure the $2 million needed for a long-term solution.

Marshall Avenue in Williston and Kimball Avenue in South Burlington will be closed starting Monday as work begins to remove the temporary bridge. Detour signs will take drivers north to Route 2 via Shunpike and South Brownell roads. The new bridge is expected to be open with at least alternating oneway traffic by December, according to the Agency of Transportation.

Work will continue in the spring of 2022 to finalize the project.