BERKELEY, Calif. -- Federal hydrologists who wrote e-mails about short-cutting quality assurance of their work on water moving through the Yucca Mountain nuclear waste site created more of a perception problem than a scientific failure, the head of a presidential oversight board said Wednesday.

Nevertheless, the Nuclear Waste Technical Review Board will report to Congress on what it learned from a daylong discussion on the controversial e-mails written mostly by a trio of U.S. Geological Survey hydrologists led by Alan L. Flint, board Chairman B. John Garrick said.

"It's regrettable this e-mail issue developed the way it did," Garrick said during a break in the meeting of the review board's panel.

"The work was overshadowed by the e-mail fiasco," he said. "The board generally believes the work was competently performed. It does not appear the science has been unduly compromised even though there was a mishandling of information."

At issue are e-mails written during a six-year period between 1998 and 2004 by Flint, his wife, Lorraine Flint, and Joseph Hevesi. The three who worked at the USGS's Sacramento office expressed a negative attitude about the Yucca Mountain quality assurance in their e-mails and suggested skirting quality assurance requirements by back-dating notebooks, making up dates of task completions and misrepresenting information, according to Energy Department managers who probed the problem.

The USGS reports on water infiltration models "were not fully compliant with the traceability and transparency requirements" for quality assurance, Gene Runkle, project controls manager for the Energy Department's Office of Civilian Radioactive Waste Management, told the panel.

"The review did not find a widespread or pervasive pattern ... of a negative attitude toward quality assurance or willful noncompliace with quality assurance requirements," he said. "We had no clear evidence that it had been falsified."

Civilian Radioactive Waste chief Ward Sproat will present the agency's findings to the Nuclear Regulatory Commission staff at a meeting March 27 in Rockville, Md.

During Wednesday's panel discussion, USGS Ground Water Office Chief William Alley said after the e-mail scandal surfaced in March 2005, it "really cast a pall around the whole branch for a while."

"It's been a traumatic experience for the USGS and we take it very seriously," he said.

Alley said the Survey has spent about $200,000 trying to clean up the Yucca Mountain water infiltration work and restore the integrity of the models even though they won't be used by the Department of Energy in seeking a license for the planned repository.

Instead, the Department of Energy has hired Sandia National Laboratories develop new infiltration rate estimates and maps by redoing the models using the data and measurements that Flint's team compiled over more than a decade of work at the mountain, 100 miles northwest of Las Vegas. The price tag on that unfinished work was not available.

Flint talked about the work elaborating on how his team sometimes set up camp during heavy rainstorms to watch how water moves on and around the ridge and to collect data on how it descended through plant-covered soils and exposed rock faces. Boreholes were monitored in channels and near earthquake faults.

Much of the surface runoff that travels to the depth of the planned repository comes through fractures in the ridgetop and trickles through side slopes, he said.

He said the data is credible and trustworthy despite the "perceived" shortcomings with its quality assurance traceability and transparency."

"There was no problem with quality assurance. It was a perceived problem," he said after his presentation.

"The perceived problem was that people didn't understand some of the wording that was used and the inner workings of how the program was going at the time," said the 54-year-old Flint.

He cited an example of an e-mail discussing a quality assurance audit in which the auditors wanted to see a scientific notebook.

"Because everything we had was electronic and all the records were electronic, the models were electronic, the input files, I think the e-mail said, 'Well, I'm going to have to make up a notebook.'

"People thought that meant you were going to fake a notebook," Flint said. "What that really meant was you were going to take your electronic data, put that into one of these green record books and document the pages and sign them, which was done all the time. ... And that was one of the kinds of mistakes that was made."

Another example, he said, was an e-mail that discussed keeping two sets of records: "One to keep Q/A happy and one I use in the model. ... That's an example of the kinds of things that were sort of blown out of proportion."

Regardless of Flint's assertion, an Energy Department spokesman for the Office of Repository Development in Las Vegas, said the modeling work is being redone because of questions about its integrity.

"There can be no question if we are to have a license application," said the spokesman, Allen Benson. "There can be no question about the integrity. As a result we are taking another look at the work that was done."