The U.S. Army Corps of Engineers in partnership with the New Jersey Department of Environmental Protection, is conducting a study to document the feasibility of implementing a flood risk management project in the Township of Denville, New Jersey. For additional information please click the link below.
Denville Flood Risk Management Study Public Notice

Denville Study Overview Denville Recommended Plan
The U.S. Army Corps of Engineers, New York District (USACE) has partnered with the New Jersey Department of Environmental Protection (NJDEP), the non-Federal sponsor, and the Township of Denville to investigate the feasibility of flood risk management solutions to riverine flooding from Rockaway River and Den Brook in the Township of Denville. USACE is releasing a draft Integrated Feasibility Report and Environmental Assessment (“draft report”) for the Rockaway River and Den Brook, Denville Township, Morris County, New Jersey, Continuing Authorities Program (CAP) Section 205 Flood Risk Management Study to document environmental analysis completed for flood risk management alternatives examined in this study in accordance with the National Environmental Policy Act of 1969, as amended.
Township residents and businesses have suffered extensive losses and damage from multiple flooding events in recent decades, including Hurricane Irene in August 2011 and Tropical Storm Ida in September 2021. Previous flooding impacts consist of inundation of low-lying areas including homes, businesses, and roads in the Downtown Business District.


Left: Flooding along Route 46 in Denville Township from Hurricane Irene in 2011 (Source: Steve Hockstein/For The Star-Ledger).
Right: Flooding from Hurricane Irene on Broadway in Downtown Denville Township (Source: Township of Denville).
Study Area:
The Township of Denville, New Jersey is located about 25 miles northwest of Newark, New Jersey, in the north central part of the state. The Township is mostly developed, with the densest development being a mix of residential and commercial land uses located south of Rockaway River. The study area is approximately 130 acres and consists of residential and commercial areas. It is bounded on the North by the Rockaway River, on the South by U.S. Route 46, on the east by Rockaway River, and on the West by St. Mary’s Place. Denville is highly vulnerable to riverine flooding from the Rockaway River and Den Brook.

Denville Study Area
Authorization:
This study is being carried out under the Continuing Authorities Program (CAP), Section 205 of the Flood Control Act of 1948 (Public Law 80-858), as amended, which allows USACE to plan, design, and construct small flood risk management projects. Projects are cost-shared 65% federal and 35% non-Federal, with a maximum federal contribution of $10 million per project.
Status:
As a part of this study, which is an iterative process, the Project Delivery Team (PDT) has analyzed several different flood risk management alternatives. Throughout the process the PDT has coordinated their work with the New Jersey Department of Environmental Protection (NJDEP), who is the non-Federal sponsor, and the Township of Denville, who is a stakeholder on the project. Alternatives studied to date have included various structural measures such as floodwalls with closure gates, floodwalls in combination with road raisings, and diversion culverts. None of these structural alternatives analyzed were found to be economically justified so they could not move forward.
In addition to the structural alternatives the PDT has also analyzed nonstructural measures such as elevations, wet floodproofing, and dry floodproofing. The nonstructural analysis conducted by the PDT identified multiple groups or clusters of structures within the study area that were economically justified which indicates the benefits outweighed the costs. On November 20th, 2020 the PDT briefed our higher headquarters, USACE North Atlantic Division (NAD), at a Tentatively Selected Plan milestone in which approval was given to advance the nonstructural plan and complete a draft integrated feasibility report and environmental assessment for public release on the fall of 2023.
The draft report was developed following the public comment period. Currently the final report is in the final stages with completion slated for late 2024. Upon completion of the final report, the findings will be coordinated with the NFS as well as the city of Denville, and then formal submission to HQ USACE for final review and approval will occur. Upon approval of the final decision documents, the design and implementation phase will be subject to availability of funding in coordination with non-Federal sponsors and local partners.
Mailing Address:
U.S. Army Corps of Engineers,
New York District, Planning Division
Subject: Denville Study
Jacob K. Javits Federal Building
26 Federal Plaza, Room 2145
New York, NY 10278-0090