Climate Resiliency Harbor Study Results

Conceptual strategies to meet a continuous 11 ft NAVD88 DFE

October 20, 2021 By Marco Boer 

After a long deliberative process with support of many stakeholders and studies, the Town
has agreed to replace and raise by about 4 feet the Inner Harbor wharfs to a uniform 11
feet, the current height of Whitney Wharf. Funding for replacing/raising the first out of
three wharves (Town Pier, Veterans, and Barnes) was approved at the 2021 April Town
meeting. The projected cost to replace/raise Town Pier is $5.6M, excluding any reductions
to Hingham tax payers from Federal and State grants.

As part of the permitting process, the Hingham Conservation Commission required a study
to determine whether or not raising the wharves would adversely impact abutters by
deflecting wave action onto their properties. The study conducted by Woods Hole Group
concluded that there would not be adverse impact. Both private marinas have expressed
interest in raising their wharf to cr predicts (with lots of caveats) that the 11 feet height
should be sufficient to protect the Town’s transportation routes and downtown areas from
catastrophic flooding through 2030-2050 (the 2018 winter storm that topped the wharfs
was considered a 50-year storm at about 9 feet). The design of the new wharves is such
that an additional 1.5 feet of stone can be added at a future date, although that would
require all other waterline structures to be raised as well.

Beyond 2030-2050, the study suggests adding layered defenses stepped back from the
waterfront. Included are suggestions for raising the shoreline/wharves even higher; a
tiered waterfront; a setback system, and roadside barriers.

The cost of raising the shoreline is estimated at $36 million in today’s dollars. Other
approaches call for allowing storm surge to flood the wharves, but stopping the water
through land/hardscaping closer to Route 3A. A tiered waterfront would slope the land
behind the wharves to a higher level (like a berm), with an estimated cost (excluding
utilities/building re-location of about $15M. A set-back system takes the concept of a
tiered waterfront one step further, adding flood walls, elevated roads, and berms closer to
Route 3A. The cost for a set-back system is estimated at $13M. The fourth
recommendation is a roadside barrier, without a tiered waterfront or setback system. The
movable barriers would only be deployed during storms, as to allow vehicles and
pedestrians to enter/exit during normal times. Movable barriers are currently in use near
the Boston Aquarium T-station. The cost of movable roadside barriers is estimated at

It is the Harbor Development Commissions belief at this time that raising the wharves to
11 feet will be sufficient to protect the Town’s transportation and down town infrastructure
for the foreseeable decades, striking an economic balance between near-term and long-
term protection. Should sea-level rise be worse than predicted in the decades ahead, the
Town should plan for contingency resiliency measures as recommended by Woods Hole

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