The National Research Council recommended in a 73-page report that the secretary of the Army establish a Corps staff to determine on a case-by-case basis if a project review should be conducted internally or by an outside group.

Projects that are costly, controversial, include a large geographical region or are environmentally sensitive should be reviewed by an independent panel, it said.

"A big part of (this study) is restoring credibility to the Corps," said David Moreau, a professor at the University of North Carolina and one of the authors of the report. "If the Corps chooses to ignore the comments of the reviewers, they do so at their own peril."

In 2000, Congress asked the National Research Council to examine the Corps' procedures after questions about its $60 million study that endorsed upgrading the aging lock and dam system in the Mississippi River.

Several independent studies, including one by the U.S. Office of Special Counsel, found the Corps manipulated some data to justify the Mississippi River project.

The Research Council is part of the National Academy of Sciences, a prestigious group of U.S. scientists and engineers that offers advice to Congress and the government.

In its report, the council said large Corps planning projects should be reviewed independently several times, especially for plans that are controversial.

It recommended Congress establish a separate advisory panel to analyze the Corps' review board and make suggestions for how it can be improved.

Environmental groups and other members of the public would have 60 days to appeal to the Corps if they believed a project should have been reviewed externally.

The Corps said it was reviewing the new recommendations.

"In many respects, it's a back-to-basics approach," said Maj. Gen. Robert Griffin, director of civil works with the Corps. "We are glad to have this report in hand, and are beginning to review it."

Moreau said a review panel would push the Corps to produce better studies with more solutions.

"One would expect the Corps would have some apprehension about the loss of authority and loss of control when outsiders have a chance to look at their product before they've had a chance to get through with it," he added.

The council estimated the proposed review process would cost about $2 million a year.

Senior officials with the Corps told a Senate Environment panel last month that they supported the creation of a federal interagency task force. The Corps has $52 billion in unfinished projects and has been urged to scrap some of them.