The Board of Directors of the Association of Dam Safety Officials has selected the Lake Lenape Dam Rehabilitation and Spillway Reconstruction project as its National Rehabilitation Project of the Year. The award will be presented at a special luncheon to be held in conjunction with the 2026 Dam Safety Conference Aug. 31 in Raleigh, North Carolina.
According to the ADSO, the top project award recognizes developers of a unique remedial design that advances state-of-the-art dam safety and exemplifies high professional engineering standards.
The Lake Lenape Dam along the Wild and Scenic Great Egg Harbor River, originally constructed in 1879, is a potentially high-hazard dam jointly owned by the County of Atlantic and the Township of Hamilton, and regulated by the New Jersey Department of Environmental Protection. The Great Egg Harbor River flows through the dam from forest and agricultural areas 50 miles upstream, through Lake Lenape and into the Great Egg Harbor Bay and finally, into the Atlantic Ocean.
In the 2010s, the dam was rated in poor condition due to deficiencies including deteriorated powerhouse sluice gates and low-level outlet pipes, deficient spillway capacity and stability, and voids in the earthen embankments. These deficiencies caused serious instability in lake levels and raised public safety concerns, spurring the owners to a comprehensive solution.
The project was designed by WSP-USA and constructed by South State, Inc., and rehabilitation conducted over two phases, and was completed in February.
The first phase was the rehabilitation of the powerhouse to function as the future low-level outlets for the dam and water bypass during construction of the new spillway. This included removal of the electric turbines, concrete repairs, and the installation of new motorized sluice gates. The second phase included the removal of the existing spillway and low-level outlets, installation of a new concrete labyrinth spillway and concrete apron, and the grouting of voids within the east and west embankments. This creative two-phase approach meant the project was executed without needing to adjust lake levels.
Congressman Jefferson Van Drew earmarked $4.6 million for this project in the Fiscal Year 2022 Homeland Security Appropriations Act through FEMA’s Pre-Disaster Mitigation account under a new process called Community Project Funding. It was the first dam replacement in the country to receive Community Project Funding.
The rehabilitated structure meets all current design requirements, increasing flow capacity by 3.7 times and enabling mechanical stabilization of normal pool elevation. The design process leveraged innovative applications of computational fluid dynamic modeling to develop what is now the largest labyrinth spillway dam in the state of New Jersey.
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