US Army Corps of Engineers
New York District Website

More about HATS

The New York New Jersey Harbor and Tributaries focus area feasibility study, which will include a tiered Environmental Impact Statement, is evaluating five initial alternatives, which currently are comprised of measures that address severe coastal storm risks for specific geographic regions within the study area, in addition to the no action alternative.  These five alternatives encompass a variety of water- and land-based measures identified throughout the estuary at areas of high projected coastal storm risk and include combinations of shoreline structures, such as beach nourishment, levees, floodwalls and seawalls, and storm-surge barriers.  This initial range of alternatives was developed in part from the analysis provided in the North Atlantic Coast Comprehensive Study, as well as coordination with the States of New York and New Jersey and the City of New York.  The alternatives are taking into account other ongoing and planned actions being taken within the study area by the Corps, other federal agencies, both states and New York City, and other municipalities.

The feasibility study will develop information to distinguish between alternatives so that ultimately a recommended plan can be identified.  Based upon available information and analyses, a draft report describing the alternatives, their benefits, costs and environmental and social impacts is scheduled to be available for agency and public review in late summer of 2020.  The Corps will then review the comments received as part of the agency and public review to determine what, if any, additional analyses, may be warranted to refine the alternatives and possibly add further measures that may be justified on a building-to-building basis (e.g., non-structural measures) or that may address areas that suffer from more frequent (and typically less severe) coastal storm risks (e.g., natural and nature-based features).  Additional analyses may result the preparation of a subsequent draft prior to the completion of the final report and the selection of a recommended plan.  As project details are developed during Preconstruction Engineering and Design, consideration of environmental and social impacts will continue to be evaluated.


The study non-federal sponsors are the New York State Department of Environmental Conservation and the New Jersey Department of Environmental Protection.  The City of New York is involved in this study through a partnership with the New York State Department of Environmental Conservation.


January 2020 Update: 

A new Notice of Intent (NOI) was published in the Federal Register (85 FR 1807). USACE had issued an NOI previously on this study on February 13, 2018.  However, with the extended 6-year study schedule, USACE withdrew the prior NOI and is posting this new one closer to when the draft Tier 1 Environmental Impact Statement will be released, summer of 2020. 

Click here to see the Notice of Intent.

The public is invited to submit comments at the meetings and/or by mail to:

NYNJHAT Study Team, Planning Division
U.S. Army Corps of Engineers
26 Federal Plaza Room 2145
New York, NY 10279-0090 

or by e-mail to:

Please include the project title and the commenter's contact information with submitted comments. Please provide comments within two weeks of the last public meeting to ensure maximum utility. Comments received after this time will still be welcome.

For more information and alerts please read the project Fact Sheet or email us at

NY & NJ Harbor & Tributaries Focus Area Feasibility Study (HATS)

Coastal storms have severely impacted the North Atlantic Coast of the United States, including the New York-New Jersey Harbor region.  In response to these storms, the US Army Corps of Engineers (Corps) is investigating measures to manage future flood risk in ways that support the long-term resilience and sustainability of the coastal ecosystem and surrounding communities, and reduce the economic costs and risks associated with flood and storm events.  In support of this goal, the Corps completed the North Atlantic Coast Comprehensive Study, which identified nine high-risk, focus areas on the north Atlantic Coast for further in-depth analysis into potential coastal storm risk management measures.  One of the nine areas identified was the New York-New Jersey Harbor and Tributaries study area.



About the North Atlantic Coast Comprehensive Study

Map of the Study Area

The U.S. Army Corps of Engineers recently completed a report detailing the results of a two-year study to address coastal storm and flood risk to vulnerable populations, property, ecosystems, and infrastructure affected by Hurricane Sandy in the United States' North Atlantic region.

This, the North Atlantic Coast Comprehensive Study, is designed to help local communities better understand changing flood risks associated with climate change and to provide tools to help those communities better prepare for future flood risks. It builds on lessons learned from Hurricane Sandy and attempts to bring to bear the latest scientific information available for state, local, and tribal planners.

The conclusions of the study, as detailed in the final report, include several findings, outcomes, and opportunities, such as the use of a nine-step Coastal Storm Risk Management Framework that can be customized for any coastal watershed. 


Map of study area

Geospatial and Modeling Products

Note: Geospatial data and other GIS layers generated as part of the study can be viewed in the USACE CorpsMap viewer. 

sample of geospatial products

NACCS geodatabaseThis database contains vector GIS information from various NACCS geospatial analyses. It also has features used to generate report maps and figures, including base map features. Refer to ArcGIS metadata for more information about each feature. 

Raster geospatial products: These are raster files presenting results of the NACCS exposure analysis, risk analysis, future mean sea level inundation mapping, and housing density projections. These products were generated using the best available data at the time and may or may not accurately reflect existing or future conditions. Refer to ArcGIS metadata for more information about each file. 

Barrier Island Sea Level Rise Inundation Assessment: The back bays of barrier islands to the bay side of beaches and dunes as well as other areas of the North Atlantic Coast including embayments and harbors are at risk of storm surge and tidal flooding via barrier island inlets. Long Beach Island, New Jersey was identified for the NACCS Barrier Island and Back Bay Example to present an illustrative example of how a beach and dune system would perform based on sea level change inundation scenarios as well as the impacts of coastal flooding from back bay areas. This example is not intended to evaluate the actual coastal storm risk and consequences. Click here to go to access the report.


Coastal Hazards System: The Coastal Hazards System (CHS) is a coastal storm hazard data storage and mining system.  It stores comprehensive, high-fidelity, storm response computer modeling results including climatology, surge, total water levels, waves, and currents and corresponding measurements.  Extremal statistics and epistemic uncertainties of the processes are also stored, and the data are easily accessed, mined, plotted, and downloaded through a user-friendly web interface.  CHS regional data are comprehensive, uniformly spanning the coastal region and practical probability space. The CHS is available online at

Sea Level Affecting Marshes Model update algorithm: This algorithm has only been implemented as a stand-alone FORTRAN code; implementation into SLAMM is done by the developers to maintain consistent code management. 

Primary Productivity
For the purposes of this algorithm, primary productivity refers only to wetland vegetation; it includes both above- and below-ground production. Both mechanisms are lumped into a general organic production term, which then is used to modify bed elevation.The algorithm includes both primary productivity and marsh collapse. 

Source Material
This algorithm is based on the relative elevation sub-model presented in the following source:
Couvillion, Brady R., Gregory D. Steyer, Hongqing Wang, Holly J. Beck, and John M. Rybczyk (2013). “Forecasting the Effects of Coastal Protection & Restoration Projects on Wetland Morphology in Coastal Louisiana under Multiple Environmental Uncertainty Scenarios” Journal of Coastal Research: Special Issue 67 - Louisiana′s 2012 Coastal Master Plan Technical Analysis: 29-50. 2013.


Projected Coastal Flood Increases: 2018 to 2118

Potential Impact of Anticipated Sea Level Change on Coastal Areas by 2100

Potential effects of anticipated sea level change to coastal communities by 2100 (at a non-specific location)

Public Meeting Presentation