Long Wharf East & North Seawall Rehabilitation

Background

Boston’s historic Long Wharf is located in the Central Wharf District of downtown Boston, extending eastward into Boston Harbor. Long Wharf is a public open space owned and managed by the City of Boston. Due to the site’s elevation relative to high tide, it is vulnerable to tidal action causing the lower Harborwalk level to become inundated on a regular basis. In 2020-21, a seawall stabilization project was completed along the southern face of the wharf. A void in the eastern face of the wharf was observed at the start of construction, prompting the fabrication and installation of a steel brace to prevent further settlement of the surrounding blocks. Since then, topside conditions have continued to deteriorate as the remaining void in the seawall face is subject to tidal and wave action. To address these issues and enhance coastal resiliency, Boston Planning and Development Agency (BPDA) collaborated with Foth to identify and recommend solutions to address the structural deficiencies on the eastern face.

Approach

Our team began by updating existing site conditions within the project area, including the topographic and bathymetric survey data previously collected by Foth in 2018, to create a comprehensive base plan of the project site. We inspected, assessed, and documented the condition of the existing infrastructure, both topside and below the waterline. Findings were provided to BPDA to determine the scope of the seawall rehabilitation work, and to identify items to consider for a separate project. As part of the inspection report, we provided a 3D model of the existing wharf structure to help the BPDA visualize the existing structural condition, highlight deficiencies, and help facilitate internal and stakeholder coordination during the planning phase for the work.

Upon receiving our design alternatives and preliminary construction cost estimates, BPDA worked with Foth to evaluate the opportunities and challenges of each option and gather feedback from project stakeholders. Once the preferred alternative was selected, we prepared, submitted, and coordinated the necessary local, state, and federal permit applications to advance the project to construction. We completed the final design and bid package, including detailed construction plans, technical specifications, and a comprehensive construction cost estimate, concurrently with the final stages of permitting to expedite the bid advertisement process. We supported the BPDA throughout the public bid process and award of the contract to a qualified marine contractor.

The Notice to Proceed for construction was issued in 2024, and Foth is currently providing construction support, oversight, and administration services. The Long Wharf East Face seawall project will rehabilitate approximately 110 linear feet of granite seawall and is expected to be complete during the summer of 2025.

In February 2025, BPDA initiated similar services for the north-facing seawall to stabilize the wall, extend its service life, and reduce the need for costly maintenance. To date, Foth has performed a site assessment of the existing granite block seawall and collected updated topographic and bathymetric data for the project area. Additionally, Foth performed a photogrammetry survey which was merged into a 3D mesh representing a digital twin of the granite block seawall. This detailed visual representation allows non-technical stakeholders to view and understand the site conditions.

Results

Our team is currently preparing design alternatives which will be presented to BPDA as part of the assessment report. Once an alternative is selected, we will proceed with permitting. bid phase, and construction administration services.