US Army Corps of Engineers
Philadelphia District & Marine Design Center

Study Background & Status

The Army Corps of Engineers was given authority under the Water Resources Development Act (WRDA) of 1986 to conduct a reconnaissance study and any ensuing feasibility level investigations in the Delaware River Basin for the purposes of flood risk management and associated ecosystem restoration. Separate authorization in 2005 underscored the need for these issues to be addressed. A reconnaissance report was completed in March 2003. USACE and NJDEP entered into an agreement to perform a cost-shared feasibility study for flood risk management projects. This study is an interim response to the legislative authority. The opportunity remains for other non-Federal entities to cost share with USACE on additional interim studies in other portions of the Basin.

Prior studies and reports have been reviewed to gain insight into the findings and conclusions of previous investigations of the study area. For example, the Delaware River Basin Study Survey Report (August 1984) analyzed non-structural flood control measures in 58 communities along the main stem Delaware River. However, actions in only 12 communities were economically justified, and would benefit only a small portion of the floodplain. To assist in problem identification, the flood history has been researched for each community in the study area under consideration. Site visits and interviews with local officials and residents were conducted to provide both historical and current information.

We are also investigating the existing conditions of key parameters in the study area (e.g. soils, climate, vegetation, wetlands, fish & wildlife, endangered species, archeological & architectural resources, hazardous waste, socioeconomics). An inventory of all structures in the floodplain has been conducted and river flows modeled to begin determining the potential for flood damages under existing conditions. Population and land use trends are being identified to project what damages may occur in the future if no flood risk management techniques are implemented.

Based on structure inventories, economic, hydrologic, and hydraulic analyses, and calculation of existing and projected damages, it appears there are two possible locations for implementation of structural flood risk managements, with one area also including nonstructural features: 

  • In Greenwich and Logan Townships, there is potential for a mixed levee and floodwall to protect structures in a developed area known as Gibbstown. Other structures in this area may be treated with nonstructural flood risk management measures. 
  • There is the potential for a levee and floodwall at Alexauken Creek and the D&R Canal in the city of Lambertville. 

UPDATE: Due to public concerns, the General Investigation study is on hold per non-Federal sponsor request, pending consideration of alternative opportunities.  The Lambertville portion of the study has been converted to the Continuing Authorities Program.