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FACT SHEET - Validation Study and GRR (Green Brook NJ Sub-Basin)

Flood Risk Management Project

U.S. Army Corps of Engineers, New York District
Published July 25, 2023

DESCRIPTION: The Green Brook Sub Basin is located within the Raritan River Basin in north-central New Jersey in the counties of Middlesex, Somerset and Union. It encompasses 13 municipalities and drains approximately 65 square miles of primarily urban and industrialized area. For the majority of the project area, the most damaging floods of record resulted from the August 2, 1973 storm, Tropical Storm Floyd on September 16, 1999 and April 15-17 2007 Nor’easter. Eight deaths were attributed to these floods. The Final General Reevaluation Report (GRR) and Supplemental Environmental Impact Statement (SEIS), dated May 1997, recommended flood protection for the Lower Basin and Stony Brook Basin, and is supported by the project sponsor, the New Jersey Department of Environmental Protection. Based on this report and input obtained during the public review period, the State of New Jersey requested that the upper portion of the project be deferred, pending additional consideration of alternatives.

The State of New Jersey in 2015 requested that a reevaluation of the deferred upper portion of the project be initiated. This effort is being accomplished in two phases.  Phase I was the Validation study which was Construction General (CG) funded and was cost shared 75 percent Federal and 25 percent non-Federal.  Phase II is the GRR which was authorized in the Water Resources Development Acts of 2020 and 2022, is General Investigations (GI) funded, and is 100 percent Federally funded under the Disaster Relief and Supplemental Appropriations Act of 2022 (DRSAA) up to $3,200,000. 

AUTHORIZATION: This project is authorized for construction in Section 401a of the Water Resources Development Act of 1986. The GRR is authorized in the Water Resources Development Acts of 2020 and 2022.

STATUS: Following the 1997 GRR, several authorized project measures have been constructed in the Lower Basin with others in the course of design or awaiting funding. In a letter dated April 6, 2015, the New Jersey Department of Environmental Protection (NJDEP) requested that the U.S. Army Corps of Engineers (USACE) initiate a reevaluation of the deferred Upper Basin of the Green Brook Authorized Project.  Given the significant time that has passed since the project was authorized in 1986 and since the release of the May 1997 GRR, the District initiated a Validation Study in order to validate the results of the current authorized project.

Revised features could include non-structural work such as floodproofing, buy-outs, elevation of structures; channel modifications either small in scale or in combination with other measure(s); a diversion tunnel; levees or floodwalls; a dry detention basin at another location in Upper Basin; and other features. The FCSA for the Upper Basin was executed 28 September 2022 with NJDEP as the non-Federal sponsor. The Alternatives Milestone Meeting was successful on 2 February 2023 and screened out large-scale levees and floodwalls and a diversion tunnel. The Tentatively Selected Plan milestone is scheduled for December 2023 with a release of a draft feasibility report and NEPA document in February 2024.



Nathanael Wales, PE
Project Manager
P: (917) 790-8731
Email: Nathanael.T.Wales@usace.army.mil
U.S. Army Corps of Engineers, New York District
Programs and Project Management Division
26 Federal Plaza
New York, NY 10278