The most ambitious of the six plans, and the one environmental groups fear the most. Courtesy USACE
Plans to protect the New York City Harbor from another Hurricane Sandy by constructing onshore barriers and giant seawalls reached a milestone in February as the government released the last report before a plan is selected.
The U.S. Army Corps of Engineers (USACE), along with New York and New Jersey are considering six different options, four of which Hudson Valley environmental groups have lambasted for their potential effects on the Hudson River. The groups also say these options would do absolutely nothing to prevent flooding from sea-level rise.
The barriers in the six plans can be split into two groups: onshore barriers preventing water from inundating the land, whether it is from the quick blast of a Hurricane’s storm surge or the slow crawl of sea-level rise from global warming; and seawalls, whose gates would only close in storm conditions, otherwise staying open to allow water and ships to pass — as well as the slowly rising sea as temperatures rise in coming years.
The most ambitious option, and the one environmental groups most oppose, is a five-mile seawall stretching from New Jersey to Queens paired with a second seawall across the Long Island Sound from the Bronx to Queen’s north shore.
A second option consists of five smaller seawalls, and two other options consist of a combination of seawalls and onshore barriers. The final option is to only build onshore barriers, and the report also considers the results of doing nothing.
For more on the different options, click here
One of these options will be selected in January 2020. The 134-page February report will be the most significant information released to the public before then. Here are its 10 biggest take-aways.
1. There was a large, anxious response from the public to the plans
The USACE received 4,250 comments from the public during the project’s 122-day scoping period, 3,295 of which were form letters, according to the report.
The comment period was originally 45 days, ending on Aug 20, 2018, but was extended until Nov. 5 after political pressure mounted. Elected officials, including state Assemblymembers Didi Barrett and James Skoufis and state Sen. Terrance Murphy, demanded more time, and eight municipalities passed resolutions requesting an extension.
The “most ubiquitous” of all the comment themes were those concerned about environmental impacts, with 91 percent of all submissions addressing this topic, according to the report.
Hudson Valley Environmental groups Riverkeeper and Scenic Hudson have questioned how the options would affect the Hudson River, especially the New Jersey-Queens barrier and the option only including seawalls, as they effectively divide the river from the Atlantic Ocean.
The Hudson River is at sea level and is therefore tidal, taking in sea water as it flows northward during high tide and expelling it back into the ocean during low tide. The groups say the barriers would cut off this flow, inhibiting the migration of fish, backing up pollutants in the New York City Harbor, causing algal blooms and unbalancing the river’s oxygen levels.
Concerns about sea-level rise also dominated the comments, with 84% addressing this, many of which stated storm surge flooding should not be addressed without first addressing sea-level rise, according to the report.
Other popular comments were concerned about river-to-ocean ship navigation, had questions about the project’s cost and timeframe, or stated there was not enough available information on the projects, according to the report.
2. The seawalls would do nothing to address sea-level rise
Riverkeeper President Paul Gallay said studying how to mitigate storm surge alone was like “the sound of one hand clapping.”
Paul Gallay. Courtesy RIverkeeper
“You can’t solve the problems of the region if you don’t solve for both storm surge and sea-level rise,” he said.
The study is a product of the Disaster Relief Appropriations Act of 2013, which gave money for the Hurricane Sandy recovery and to study ways of mitigating future disasters. The study and its resulting project are confined to addressing coastal storm flooding, not the slow inundation of sea-level rise.
Though coastal storms will cause more flooding with climate change, and the study is addressing this result of sea-level rise, it cannot address the root problem of everyday flooding from higher seas.
The onshore barriers, however, would address sea-level rise as well as flooding from storms, the report states.
Onshore barriers would also be erected behind the seawalls to “address residual coastal flooding impacts under [non-storm] conditions due to increasing sea level and during more frequent, less severe coastal storms when the surge gates would not be closed.”
In the options with seawalls, the USACE would essentially be building two sets of barriers: the seawalls environmentalists fear to address storm flooding, and onshore barriers, because the USACE realized seawalls would only address one form of flooding.
3. The New Jersey-Queens Barrier would be a massive undertaking
The option with this barrier would cost $119 Billion and take 25 years to complete, according to the report. To put this in perspective, this is about $500 for every person currently living in the U.S.
The cost would be split between the federal government, New Jersey and New York, according to the report. Congress would seemingly have to appropriate funds to build it, since the amount appropriated to the area to both recover from Hurricane Sandy and prevent future floods was less than $25 Billion.
This option also includes a second seawall between the Bronx and Queens about four-fifths of a mile long, and a short seawall in the Bronx. The first two seawalls would be connected to more than 26 miles of onshore barriers, according to the report.
Riverkeeper Vice President for Advocacy Jonathan Lipscomb warned about long-term projects, noting NYC and its environs would be susceptible to flooding until the project’s completion date, and adding onshore barriers already being constructed separate from the federal project were addressing flooding now.
4. The seawalls would be mostly permeable
This was an important issue with environmentalists — the seawalls would include gates open in non-storm conditions to allow for passage of ships, wildlife and nutrients, but how wide would they be?
The New Jersey-Queens barrier would have 31,480 feet of “numerous navigational surge gates and auxiliary gates” with a relatively small span — about 1,000 feet — of “barrier connectors” without gates.
Of the nine different seawalls in the options, the report only makes a distinction between the gates and the barrier connectors when listing three of their lengths — the rest just list a length of the barrier as a whole. Like the New Jersey-Queens barrier, the two other barriers with detailed measurements are mostly gates, with less than ten percent of their lengths made of barrier connectors.
5 .The seawall gates would close about every two years — to start
The gates would close for a “50 percent flood” — a coastal flood occurring on average every two years, according to the report.
The next phase of study will attempt to calculate how often individual gates would close, according to the report, which seems to suggest some gates might close less often than the base rate.
But, as ocean levels rise, smaller storms would threaten more damage to the coast, and “surge gate closure may also become more frequent,” according to the report.
6. Five of the options include surge protections for the Hudson Valley
Onshore barriers in the Hudson Valley present in three of the six options. Courtesy USACE
The two options with the largest seawalls essentially would separate the Atlantic Ocean from New York City Harbor and the Hudson River when closed, thereby protecting the Hudson Valley from ocean flooding, which can happen because of the tidal river’s position at sea level.
Three other options include onshore barriers for three Hudson Valley locations, which would help mitigate flooding from the coast in Ossining and Tarrytown in Westchester County and Stony Point in Rockland County.
This does not include local Hudson Valley initiatives, either planned or hypothetical, to mitigate flooding.
As is the case with NYC, seawalls would only protect the Hudson Valley from ocean flooding when closed during major storms, but the three onshore barriers would prevent flooding all the time.
The seawalls would also only protect from water coming up the river, as opposed to traveling downriver from inland flooding.
A large number of public comments received by the USACE questioned whether the seawalls would cause more flooding.
When the gates close, the water flowing downriver would have nowhere to go, and could theoretically back up and cause flooding in the Hudson Valley. This may be exacerbated if a wide-spread storm hits, such as a hurricane, since it could dump rain inland that would rush downriver only to hit closed gates.
Many people submitting comments also worried the seawalls would deflect storm surges into areas immediately outside the barrier’s protections.
The report addresses both concerns, stating any induced flooding would have to be mitigated as part of the project’s permitting requirements.
“If it is not technically possible to mitigate for the induced flood damages caused by a storm surge barrier, or if the cost to mitigate renders a plan economically unviable such that the costs exceed the benefits, then these measures would be screened out,” according to the report.
7. The “Future without Project” option only takes into consideration local projects slated in the near-future
The first of the six options being considered by the USACE is the “Future Without Project” alternative, wherein a federal-state plan to protect the New York City region does not go forward.
However, this does not mean nothing will be done to protect the shoreline. Other projects are in the works, including those being constructed by the USACE, such as on Coney Island and in New Jersey.
The Sandy Recovery Infrastructure Resilience Coordination (SRIRC) Group lists more than 400 other projects to mitigate coastal flooding either in the planning or construction phase, according to the report.
However, these projects must be “already built, or will have funding, completed construction documents, and permits by July 2020” — months before the USACE chooses an option, much less builds it — to be included in the benefits of the Future Without Project alternative, as well as the report’s other calculations.
This winnows down the list of projects included in the Future Without Project option from 400 to 160.
Riverkeeper Paul Gallay said the USACE “can do a better job of taking the smaller mitigation efforts into consideration.”
“I feel if they’re designing [a project] that won’t be in place for 25 years, they need to take a longer-term horizon into consideration for onshore work as well,” he said.
8. The option with the second-largest barriers is the most cost-effective
The third option, which divides New York Harbor and the Hudson River from the Atlantic with three seawalls and includes a fourth seawall protecting Jamaica Bay in southern Queens, is
The multiple seawalls option, which the report calculates is the most cost-effective.
the most cost-effective, according to the report’s calculations.
The report, using a middle-of-the-road estimate for sea-level rise, predicts the area will sustain $7.2 billion a year in damages on average from 2030-2100. It puts this up against the percentage of the area the different options are expected to protect, then compares it to how much each option would cost.
This is one of two methods used by the report to calculate cost-benefit analyses, and both state the option including only onshore barriers would be the least cost-effective. This option only protects 3.2 percent of the area from storm surge flooding and spends more money relative to the area it covers than the other options.
Th onshore barriers-only option is the cheapest overall, but the most expensive option — the one including the New Jersey-Queens barrier — is also at the bottom of the barrel in terms of cost-efficiency, though slightly more cost-efficient than the onshore barriers-only option.
All five options that include construction (the Future Without Project option is moot in this calculation) would ultimately save the country money by protecting the shorelines, according to the report.
9. Environmental Groups Prefer the onshore barriers-only option
Riverkeeper has endorsed the option including only onshore barriers. While Scenic Hudson has not endorsed any particular option, Land Use Advocacy Director Jeff Anzevino said onshore barrier-only option “seems to have the smallest impact on the (Hudson River) estuary and is more consistent with the work that everyone is doing to address sea level rise.”
When asked about the option’s small coverage area, Riverkeeper Paul Gallay disputed the amount of coast the option would protect.
Going in the other direction and selecting an option relying on seawalls “would not protect anybody in the region because it wouldn’t deal with sea-level rise,” he said, adding these options would also have the worst environmental impacts.
READ: Environmental Groups Attack Plan Separating Hudson From Atlantic
10. A project will be chosen in less than a year
An option will be chosen in January 2020, then unveiled to the public in March 2020 as part of the first installment of the project’s Environmental Impact Statement (EIS).
The public can submit comments through that time here. The USACE is in the process of holding eight public meetings on the project, including one April 3rd at the Hudson Valley Community Center in Poughkeepsie.
The USACE was originally supposed to winnow down the six options to one or two by fall 2018 but was granted additional time and money to study the options due to the complexity of the project.
After the selection, the USACE project team will take additional public comment and must run the project through the second part of its EIS before submitting their final recommendation to USACE headquarters.
Even after an option is selected, the project can be scuttled.
Afterword: Why the shit aren’t more people covering this?
This story is getting very little coverage.
Support TOHV to unlock more content!
