As New York City proceeds with the lengthy rebuilding process following Superstorm Sandy, the Administration of Mayor Michael Bloomberg has released an ambitious report that calls for a series of measures to limit the impacts of climate change and help the city’s communities bounce back following massive storms.
The report, “A Stronger, More Resilient New York,” details a range of initiatives totaling approximately $19.5 billion, of which some $14 billion would come from a mix of federal and city funding over a period of about 10 years.
New York City’s 520-mile long coastline and waterfront structures face “significant climate risks,” says the report, principally from high waves and tidal surges produced by severe weather. The city plans to erect new structures to provide flood protection, including floodwalls, levees, and local storm-surge barriers.
The report also calls for a range of steps to make coastal communities more resilient to powerful storms, including:
• Widening or elevating beaches, reinforcing sand dunes, lining exposed shorelines with massive rocks, and placing breakers offshore to blunt the force of waves and help prevent flooding;
• Reinforcing wetlands, by altering their depth and slightly increasing their inclusion of rock and other “hardened” elements, which research shows can help reduce the impact of powerful waves;
• Creating integrated flood-protection systems, which can contain a range of features, including landscaping elements, flood-proofed buildings and bridge abutments; and
• Adding “backflow” prevention devices to ensure that water does not flow backwards through drainage infrastructure.
The report details temporary measures like deployable floodwalls that could be erected just prior to a severe weather event, and local, moveable storm-surge barriers like gates or flood walls constructed in navigable waters that could be closed ahead of an approaching storm. It also recommends construction of multi-purpose levees that in addition to providing flood protection can serve local residential, retail and commercial uses and provide transportation services, such as parking, or serve as open space.
Energy infrastructure is another focus of the report, which calls for steps to harden the city’s highly interdependent steam, natural gas and electricity networks buried deep underneath the city, and recommends diversifying the energy sources that fuel New York. Superstorm Sandy knocked out electricity service to two million New Yorkers after it slammed ashore on October 29, and several major hospitals were without heat or hot water. While service was restored to most of the affected customers within days, the outages lasted for weeks in parts of the Rockaways and Staten Island, where coastal communities were devastated by Sandy’s record tidal surge and fierce winds.
Another component of the plan is a two-part strategy to protect the one million or so buildings that populate the city, such as measures to strengthen new and rebuilt structures to meet the highest available standards, and to retrofit a large number of existing undamaged buildings to improve their resiliency.
The task is vast, given the built environment’s vulnerability to changing weather patterns. Nearly 89,000 buildings, which housed approximately 443,000 residents, were flooded during Superstorm Sandy. More than half of those buildings were situated outside of the official floodplain boundaries established by the Federal Emergency Management Agency (FEMA) in 1983 and used by the city until very recently.
The agency released preliminary updated flood maps that include 67,000 buildings, nearly double the number from 1983; nevertheless, those revised maps do not reflect the full risks to the city’s building stock, the report says. They suffer from a key shortcoming by virtue of being based on historical storm profiles that do not reflect potential changes in coastal storms due to altered weather patterns, or rising sea levels. If incorporated, these factors could broaden the city’s floodplain to include more than 88,000 buildings by 2020 and over 114,000 by the 2050s, the report says.
The 438-page report also includes a range of recommended measures for sectors including transportation, telecommunications, water and wastewater, among other critical infrastructure. The full report can be accessed here.
— By Rona Cohen