WASHINGTON – The levees that breached during Hurricane Katrina, causing the catastrophic flooding of New Orleans, had dozens of breaches along the city’s many miles rather than the much smaller number originally thought, civil engineering experts told a Senate panel led by Sen. Susan Collins on Wednesday.

The experts added that the levees might have been poorly constructed, possibly as a result of malfeasance.

“It’s disturbing to learn that inferior materials were used in some cases and contributed to the failure of the levees,” said Collins, who chairs the Senate Homeland Security and Governmental Affairs Committee, which held Wednesday’s hearing. Collins added that she has contacted the Government Accountability Office to look into the question of possible malfeasance.

The findings surprised Peter Nicholson, professor of civil and environmental engineering at the University of Hawaii and team leader of an American Society of Civil Engineers expedition to assess the failure of the New Orleans levees. Nicholson had expected a few gaps caused by overflowing waters. Instead his team found many fissures and longer-term causes.

“Many of the levee problems involved significant soil-related issues,” Nicholson said, including scour erosion, seepage, soil failure and internal erosion caused by the flow of water through a dam or embankment.

Collins said this raises serious questions about the levee system. “The levees were supposedly built to withstand a Category 3 hurricane,” she said, “but the testimony today suggests that they did not withstand even a Category 1 hurricane.”

Questions also remain as to whether the levees were constructed according to their design, according to Raymond Seed, a civil and environmental engineering professor at the University of California at Berkeley, who suggested malfeasance. Specifically, he said, some materials originally specified for construction were changed.

Nicholson said that sand and shell fill were used in the levees – materials that are inferior as embankment material because they are highly erosive, he said.

Collins added that her committee needed to further investigate what the contract specified for building the levees. “That will help us answer the question of whether there was a substitution of lower-grade materials or there were mistakes in the design of the contract,” she said.

“Either is disturbing, but obviously malfeasance is even more so,” Collins said.