New York Harbor Storm-Surge Barrier

The New York-New Jersey Harbor is vulnerable to storm surges that threaten to inundate the region, put in danger large numbers of the metropolitan area's residents, devastate much critical infrastructure and damage some of its most important economic assets. At particular risk are the most vulnerable, low-income communities located in many public housing projects located on low-lying land near to the coast. For example, research suggests that hurricanes that have hit the New York City area since 1970 are more intense or have larger wind fields, producing higher storm surge and flood risk. When added to rising sea level, what was a 500-year flood event before the anthropogenic era (i.e. pre-1800) is now a 24-year flood event and in 30 years will be a 5-year flood event. The risks to the New York Metropolitan Region also include wind and flooding damage from winter nor’easter storms which can be as serious, or even more dangerous, than rarer hurricanes. While hurricanes are short and violent, nor’easters tend to persist longer — for several days — also producing large storm surges that ride atop successive high tides that occur twice daily. But sea level rise has begun to accelerate, potentially adding an additional 3–6 feet to current sea level by the end of this century, or possibly more if the melting of the Greenland ice sheet continues at ever increasing rates and huge chunks of ice around Antarctica continue to break off. == Precedents ==

, the Netherlands|thumb Similar, albeit more modestly-sized, but still highly effective storm-surge barriers have been in operation for nearly half a century in three New England communities — the Stamford Hurricane Protection Barrier in Stamford, Conn.; the Fox Point Hurricane Barrier in Providence, R.I.; and the New Bedford Harbor Hurricane Barrier in New Bedford, Mass. Hours before Hurricane Sandy struck Stamford, the city's 17-foot-high movable barrier was closed to withstand an over-11-foot storm tide which struck western Long Island Sound (at some locations on the sound, the storm tide was even higher than the 11.5-foot storm tide measured at The Battery in New York City), devastating every waterfront community on the northwestern coast of the sound — except Stamford. Larger barrier systems protect more than a dozen major cities, including the Delta Works protecting the south of the Netherlands and the MOSE Project protecting Venice. New storm-surge barriers on Lake Borgne and Lake Pontchartrain are part of the protection for New Orleans after Hurricane Katrina. The famous Thames Barrier is typically deployed an average of about twice per year, protecting the heart of London from excessive tidal flooding. The Greater London Authority is currently studying proposals to strengthen its defenses. The new Saint Petersburg Dam was built to stop the frequent floods in the city, which had often devastated the city. It was first used on November 28, 2011, just months after it was completed, and limited storm water rise to below flood level. It prevented the 309th flood in the history of the city. == Background ==

During the same period when the New England storm surge barriers were built, the Army Corps of Engineers warned of possible catastrophic storm surge flooding in New York City and discussed a possible storm surge barrier system for New York Harbor. However there was little local interest in such a project. With funding from the Rockefeller Foundation, Mayor Michael Bloomberg, convened the New York City Panel on Climate Change in August 2008 to investigate the city's vulnerability to a variety of climate-induced risks including the risk of a major storm-surge event. At about the same time, the American Society of Civil Engineers organized a three-day conference and subsequently published a report entitled "Storm-Surge Barriers to Protect New York City Against the Deluge." After Hurricane Sandy devastated the New York - New Jersey metropolitan area in 2012, governments struggled both to recover and to plan better protection for the future, including regional storm-surge barriers. In his January 2013, State of the State address, New York Governor Andrew Cuomo proposed to "work with other government partners to timely complete a comprehensive engineering evaluation of these potential barrier systems." The City of New York, under Mayor Michael Bloomberg, organized a "Special Initiative for Rebuilding and Resiliency" (SIRR), which developed a blueprint for reconstruction that was released in June 2013, only eight months after the storm. That over-400-page document describes the demographics and morphology of the region, the storm and its impacts; provides background on extreme weather events including non-storm events such as heat and intense rainfall; describes various resiliency measures and strategies; and describes specific initiatives, studies and projects to be undertaken. Some of these projects are underway, using a combination of federal and local funds. City and regional response Despite Governor Cuomo's announced interest in storm surge barriers, Mayor Bloomberg was reluctant to proceed. But the City asked Dr. Jeroen Aerts, a professor of water and climate risk with the VU University of Amsterdam, the Netherlands, and an expert on water risk management, to compare the costs and benefits of a regional barrier system with those of smaller-scale changes like building levees around sewage treatment plants, raising subway stations entrances, constructing local storm-surge barriers, and flood-proofing or raising buildings according to the FEMA-run National Flood Insurance Program standards. At the same time FEMA intends to redraw flood maps for New York City, placing a much larger area in the flood zone. Dr. Aerts' report indicated that, assuming a middle scenario for climate change, which includes the combined effect of sea-level rise and increased storm activity, the benefit/cost ratio of investment in a regional barrier would be similar to the ratio for investment in smaller-scale changes. Despite that result, the city's SIRR report dismissed the regional barrier idea without any further study. The report listed seven reasons for doubt about the feasibility: For example, a barrier has been funded as part of an inner defensive ring for Lower Manhattan, to be integrated into the Manhattan Waterfront Greenway. At the same time that the city was implementing its own local flood mitigation strategy, the MTA, Port Authority of New York and New Jersey and many major institutions and private companies adopted their own localized plans for their facilities. Hoboken and other cities in the region have initiated their own local measures, with support from the U.S. Department of Housing and Urban Development's Rebuild by Design competition. The U.S. Army Corps of Engineers has conducted coastal storm risk reduction studies and beach restoration and resiliency projects. Because of the variety of governmental entities involved, as well as differing community reaction, there is a lack of coordination on goals and standards of storm protection among the various projects. As a result, these scattered efforts have proved to be more difficult to execute, as well as more expensive than expected, and raise doubt about how much of the shoreline will be protected in the end. Counterarguments Lost in all this activity is the conclusion of Dr. Aerts' study — that because of the expectation of rising sea level and increased global warming, by 2040 the benefit/cost ratio of a regional barrier system will far exceed the ratio for the measures the city is now taking, that a regional barrier may be needed soon, and that planning for it should begin now. The Storm Surge Working Group has provided answers to all the objections raised by the city. • A barrier system would be expensive, but the city's plan, covering many miles of vulnerable coastline, would be even more expensive. And some of the cost to shore up areas on the sides of the barriers are scheduled to be spent anyway, for example in dune-building projects on the Rockaway peninsula and on Staten Island. Even that small decrease merely offsets the equally small increase in tidal flow that resulted from digging shipping channels into the harbor over the past 150 years. • Reinforced dunes (not levees) will indeed have to be built in the Rockaways and Sandy Hook, and along Coney Island and Staten Island if the alternative barrier location is chosen. In fact in the wake of Hurricane Sandy reinforced dunes are already under construction on the Rockaway Peninsula and Staten Island. • Because of the immense lengths of the New York Bight and Atlantic shorelines (Montauk Point, N.Y. to Cape May, N.J.), research has shown that ocean water displaced by the barrier system would only increase coastal surges adjacent to the barrier by a few inches on the ocean and western Long Island Sound sides. • With normally-open storm-surge gates, barriers alone will not address sea level rise, but neither will local shoreline storm-surge projects planned by New York City, which will also have gates. The SIRR report, itself, found that by the 2050s 43 miles, or about 8%, of the city's coastline could be at risk of flooding during non-storm conditions. These coastal areas will need to be raised or otherwise protected regardless of additional protections against storm surge. The two-tiered approach of protecting local coastal areas against slowly changing sea level rise, together with 25-foot offshore barriers to hold back surges of future storms, will give future civic leaders 100 to 150 years to protect, and if necessary migrate, our urban metropolitan civilization to higher ground, and to adopt even more sweeping measures to protect the region from both sea level rise and storm surges. Another objection to barriers is that restored natural systems, such as created wetlands and oyster beds could provide the same protection. While these proposed solutions should be included in local responses because they can reduce wave action slightly, reinforce presently fragile wetlands and in some cases improve water quality, the reality is that they would be simply overwhelmed by storm surges of the magnitude experienced during Sandy. One naturalistic feature can resist storm-surge—levees or dunes. In fact most of the coastline of the Netherlands is protected in this way. A regional storm surge barrier would depend on dunes along the coast of the Rockaway Peninsula and Sandy Hook, or, for the alternative location, along the coast of Staten Island. ==Army Corps of Engineers study==

In the Fall of 2017, the U.S. Army Corps of Engineers (USACE) initiated a Coastal Storm Risk Management Feasibility Study to evaluate various proposals to address storm surge in the New York and New Jersey harbor area. The New York Harbor Storm-Surge Barrier, modified to increase permeability, is represented by two of five alternatives being considered. In December, 2020, Congress instructed the USACE to expedite the study, after the Corps had "indefinitely postponed" the project the previous February. The Biden Administration subsequently restarted by the study. A draft Feasibility Report and tier 1 environmental impact study is posted on the USACE website, a slide presentation, and meeting posters. including a critique of the Corps' TSP. The TSP is essentially a subset of the SIRR's shoreline barrier proposals for New York City with the addition of a floodwall around the Jersey City waterfront district and storm surge barriers at the entrances to Arthur Kill and Kill Van Kill to protect much of northern New Jersey. Completion of the HATS study will depend on future allocation of study funds. The schedule for the study is as follows: ==See also==