The Army Corps of Engineers used flawed data in a cost-benefit analysis studying navigation improvements to the Mississippi and Illinois rivers, according to a report from the National Academy of Sciences. The report, by the National Research Council, said the flawed results from the analysis should not be used in the project, and advised that the Corps explore less expensive alternatives for managing barge traffic on the waterway system, before it goes ahead with its lock extension plan. The lock extension project is expected to cost $1 billion. According to the report, the Corps used several faulty assumptions and data in forecasting grain shipments and in estimating the cost of demand for barge services along the waterway. "The problem lies not in the theoretical motivation behind these [economic] models, but in their implementation and data used as input," said the report. Dave Hewitt, a spokesman for the Corps of Engineers, said the agency is reviewing the report. Last February, the Army asked the National Academy of Sciences to evaluate the validity of the Corps' cost-benefit analysis that studied navigation improvements to the Mississippi and Illinois rivers, following a whistleblower's allegations of data-rigging. The navigation project has been put on hold until June 2001. So far, the Corps' cost-benefit analysis of the project has cost roughly $50 million. The report suggested the Corps study less expensive alternatives for reducing traffic congestion on the waterway, such as better scheduling and congestion fees. "Although the Corps has made important improvements in its analysis, it apparently considered lock extensions as the only means to reduce congestion, ignoring a range of less expensive options that wouldn't require rebuilding locks and dams," said Lester Lave, chair of the committee reviewing the navigation project. The report also recommended an independent group of experts, including environmental and social scientists, review the Corps' study on the navigation project. During a hearing Tuesday before a Senate Appropriations subcommittee, Lt. Gen. Robert B. Flowers, the head of the Army Corps of Engineers, said the Corps plans work with other federal agencies on how to improve the project and will incorporate the National Academy of Science's findings.