A civil engineer and forensics expert testified Friday that a shipping channel dug in the 1960s turned into a “hurricane highway” during Katrina and caused widespread flooding of eastern New Orleans and St. Bernard Parish.

Bob Bea, a civil engineer with the University of California at Berkeley, said Katrina’s flooding would have been minimal if the 76-mile Mississippi River-Gulf Outlet had not been built or if the Army Corps of Engineers had maintained it properly.

Bea said what happened in August 2005 was not a natural disaster but a “manmade disaster.”

The testimony came during the end of the first week of a federal trial against the corps. Five individuals and one business are suing, blaming the corps for flooding during the storm. The non-jury trial could last three more weeks.

The lawsuit claims Katrina’s storm surge was seriously exacerbated by the gulf outlet. More than 200,000 other claims against the corps, valued at billions of dollars, depend on the trial’s outcome.

By Bea’s account, he has spent about 10,000 hours studying the levee failures during Katrina. He specializes in studying engineering disasters and risk management.