Summary: The U.S. Army Corps of Engineers' February 1992 Final Interim Feasibility Study and Environmental Impact Statement reported that deepening the Delaware River ship channel from 40 to 45 feet was economically justified and environmentally feasible. However, GAO found that it does not provide a reliable basis for deciding whether to proceed with the project. GAO identified several miscalculations, invalid assumptions, and the use of significantly outdated information on the Corps' benefits estimate. In addition, several unresolved issues and uncertainties were not factored into the Corps' economic analysis, the outcome of which could either increase or decrease the benefits and costs of the project. Because of these shortcomings, the actual economic merits of the project will be unclear until the Corps reanalyzes it. The Corps of Engineers has largely addressed the environmental concerns of federal and state environmental agencies. However, several unresolved issues remain, including the issuance of a permit from the state of Delaware governing construction projects that affect state waters.
