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.  

 

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).

 

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.

 

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 $15 million per project.

 

 

The Final Feasibility Report and Environmental Assessment was approved in March 2026. Following approval, the New York District will coordinate with the New Jersey Department of Environmental Protection (NJDEP), the non-federal sponsor for this project, to sign a Project Partnership Agreement (PPA) and initiate the design and implementation phase. The design and implementation phase is cost shared 65 percent federal and 35 percent non-Federal and is subject to the availability of funds in the CAP Section 205 program, which are appropriated by Congress on an annual basis, and availability of funds from the non-Federal sponsor. Design of the project is anticipated to take three and a half years following approval of the PPA. Construction is anticipated to take up to two years depending on the final scope of the project and building owner’s participation. Further information will be provided to eligible building owners by USACE and NJDEP following approval of the PPA and project scope.

 

• USACE and the Township of Denville will reach out to eligible homeowners and building owners to discuss the types of the nonstructural measures, how building owners can participate, and requirements for participation.
• All flood risk management measures in this plan are voluntary, eligible building owners may elect to opt out of the plan.
• Specific measures for each building will be determined during the design phase and in coordination with affected building owners. Temporary relocation benefits may be available for certain owners while construction on the project is taking place on the building.
• Costs for implementation of recommended measures are cost-shared by the Federal Government (65 percent) and its non-Federal partners (35 percent).
• Building owners would retain certain responsibilities for maintaining measures.