A hurricane passes directly over New York City. Within an hour, harbor water levels rise 13 feet, washing over wharves and causing rivers on each side of the island city to converge.

This scenario refers to the Great Hurricane of 1821, not Hurricane Sandy almost two centuries later. But with more people living along coastlines that are being slowly swallowed by the Atlantic Ocean, the stakes are much higher. At an estimated $75 billion in damage, Sandy is the second-costliest hurricane in U.S. history.

The hurricane prompted the U.S. Army Corps of Engineers (USACE) to identify vulnerabilities along the Atlantic Ocean's coast from Maine to Virginia. Home to 16 million people, the New York and New Jersey Harbor and tributaries area was hit particularly hard. In what could become USACE's largest study to date, the agency's partnering with public agencies at all levels of government to recommend risk-reduction measures that can be adapted as necessary to minimize damage from future storms.

The "New York and New Jersey Harbor and Tributaries Focus Area Feasibility Study" is expected to produce implementable solutions that will be presented to the U.S. Congress.

What will be done in my community?
Typically, USACE studies focus on a municipality or a watershed. This one, however, encompasses many watersheds and 900 miles of coastline with the New York and New Jersey Harbor as the focal point.

"The elephant in the room was ground zero for Hurricane Sandy: the harbor and tributaries," says Joseph Vietri, director of the National Planning Center of Expertise for Coastal Storm Risk Management at USACE's North Atlantic Division.

New York communities include the south shore of Staten Island, Jamaica Bay, Rockaway peninsula, and western Long Island Sound. New Jersey's include the Raritan to Sandy Hook shoreline, Arthur Kill, the Kill Van Kull, Newark Bay, and the Passaic and Hackensack Rivers. The harbor area includes the Upper Bay of the New York Harbor, the Hudson River, East River, and Harlem River.

More communities may be added as the study progresses.

What types of risk-reduction measures are going to be constructed in my community?
Each community will choose from a menu of options to develop a plan that best addresses its needs and reflects its values.

  • Structural measures. Designed to reduce the frequency and intensity of flooding; includes putting up a floodwall, levee, beach fill, dune, or an offshore barrier.
  • Nonstructural measures. Designed to reduce damage without addressing flooding; includes elevating or buying out a house, wet or dry flood proofing, evacuations, and zoning changes.
  • Natural and nature-based features. Designed to reproduce natural defense mechanisms lost to development; includes creating marsh islands and wetlands, aquatic restoration, and placing sand on beaches.

"To say that everything should be the same is incorrect," says Vietri. "Communities can increase what they see as important and downplay what they value less."

"We have a very diverse study area in terms of topography and land use," says USACE New York District Coastal Section Chief Olivia Cackler. "A combination of measures allows us to tailor our approach by using the most appropriate measures for a community."

Having various alternatives also enables communities to compare various levels of protection.

"We want them to not just engage and review alternatives, but to advise us," says Vietri. "To me, this is a significant change in how we resolve problems."

Before communities weigh in on what blend of measures they want, USACE will perform a cost-benefit analysis. The results must show that the benefits of the project outweigh the costs. The plan with the most net economic and environmental benefits to the nation becomes apparent through this process.

There are benefits and risks with any and all combinations, so whatever a community decides may represent the best possible trade-off.

Did you learn anything from Hurricane Sandy that will be part of this study?
Hurricane Sandy highlighted strengths as well as weaknesses.

For example, says Vietri, the storm "upturned a lot of what we thought was the floodplain. Places that people thought they could go to get out of high water turned out not so much. We'll re-evaluate floodplain scale and scope, which could lead to better evacuation planning, route mapping, and shelter locations."

On the other hand, the storm confirmed that some measures work.

"Areas that had an Army Corps project, such as beach fill or levees, in place fared much better than those that didn't," says Cackler. "When there was flooding, it was substantially reduced."

"There are places in New Jersey where there were healthy beach and dune systems," says Vietri. "People in these areas had minimal damage. Literally, 200 yards down the beach where there was no project, there was complete devastation with houses and roads gone."

Will this study factor in possible climate change and sea level rise over the next 50 years?
The sea could rise 1 foot to 6 feet over the next 100 years. Given such uncertainty, it's tempting to design for the largest possible increase.

Ironically, that approach is not necessarily the most effective, cost-effective, or environmentally beneficial.

Resilient Adaptation is a planning concept that enables USACE to adapt to changing conditions as seen in real time. The agency addresses the sea level challenge via three scenarios.

"Let's say we assume there's going to be low or moderate rise and we design a seawall to hold up to this," says Cackler. "Years go by and we actually see a high rate of sea level rise. If we devise a solution using Resilient Adaptation, we build the seawall with a larger base so it's possible to add to its height instead of having to build a new, larger seawall."

"Going with the bigger plan means you're assuming more damages," says Vietri. "For example, instead of needing 100 yards of sand to replenish a beach, you think you'll need a thousand. But your environmental footprint will be larger and your environmental impact greater."

Are we actually going to see something happen from this study?
"This is so important that multiple staff from New York and New Jersey and the U.S. government worked tirelessly to execute the agreement to start the study," says Cackler. "Funding is coming at a faster rate even in this era of tight budgets."

In addition, stakeholders are moving to a more adaptive mindset. For example, more agencies are getting tougher on developers who want to build in flood zones. "I haven't seen this in my 30 years with the Army Corps," says Vietri.

"What gets me the most is the look on people's faces and the helplessness. Their resiliency pushes you to try to do something bigger and better, to search for answers that would reduce or eliminate this human tragedy. If you think I'm passionate about it, I am. We have to be. Otherwise, we'll cease to exist as an organization."

The team will strive to complete the study as quickly as possible without compromising quality. Most studies take three years, but this one will need more time.

"The goal isn't to have a controversial report that doesn't lead to anything productive and useful," says Bryce Wisemiller, Project Manager, USACE, New York District. "We want something that not only informs the region of the risk that exists now and will exist further into the future, but also to provide solutions that we can implement with them."

Information about the study and upcoming community meetings may be obtained by e-mailing cenan-pa@usace.army.mil