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

Flood Risk Management Project

Published Feb. 1, 2018

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 has requested that a reevaluation of the deferred upper portion of the project be initiated. This effort will be accomplished in two phases.  Phase I will be the Validation study which is Construction General (CG) funded and is cost shared 75 percent Federal and 25 percent non-Federal.  Phase II will be the GRR which is General Investigations (GI) funded and is cost shared 50 percent Federal and 50 percent non-Federal. 

AUTHORIZATION: This project is authorized for construction in Section 401a of the Water Resources Development Act of 1986.

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 is currently initiating a Validation Study in order to validate the results of the current authorized project. If the authorized project is not validated then this would require a Green Brook GRR which would be used to reexamine the Upper Basin features to include both the remaining unconstructed portions of the Lower Basin and the Stony Brook Basin.

Estimated Study Costs: The cost estimate for the Validation study is approximately $2.7M and is scheduled to be completed by Jan 2021.   



Mr. Robert Greco

Project Manager

U.S. Army Corps of Engineers, New York District

Phone: (917) 790-8394


Programs and Project Management Division

26 Federal Plaza

New York, NY 10278-0090






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