Project Katrina

The Army Corps of Engineers investigation into the flooding of New Orleans after Hurricane Katrina is overlooking one of the most important causes: organizational failures, according to an outside engineering group working officially with the corps.

The corps is spending about $20 million to understand the physical causes of the levee breaches that left more than 75 percent of New Orleans flooded. But the engineering group said the corps should also be looking into “discontinuity and chaos” in the creation and maintenance of the levees, according to a letter from the group to Lt. Gen. Carl A. Strock, the chief of the corps.

“No one person or organization is in charge of the New Orleans hurricane protection system,” the group wrote. Local levee boards, parish governments, state agencies and bureaucracies within the corps operate independently and sometimes in conflict with one another, and they are all but destined to miss danger signs and perpetuate mistakes, said the group, known as the External Review Panel, or the E.R.P.