NEW ORLEANS (AP) - A new study finds the U.S. Army Corps of Engineers at fault for the floods that followed Hurricane Katrina, a newspaper reported Wednesday.

It said the Corps ignored hurricane research, built levees and floodwalls lower than Congress ordered, and failed to properly maintain them, according to The Times-Picayune, which obtained a copy before the report was released Wednesday.

The Team Louisiana report is Louisiana's official state study of the levee failures.

It repeats technical findings of several other reports made last year but focuses more on the decisions behind those problems, said Ivor van Heerden, a director of the LSU Hurricane Center and Team Louisiana's leader.

"It's one thing to use modern, state-of-the-art computer modeling and determine what happened, and the other teams did a very good job of that," he said. "But the only way to really understand if mistakes were made was by relying entirely on using the (engineering) tools the corps would have used - or should have used - when they did their designs."

A spokesman for the corps' hurricane protection office in New Orleans said officials there have not yet seen the report and had no comment.

Among key findings:

The Corps based its designs on research through 1959, doing nothing to strengthen them when research in 1972 and 1979 increased the projected strength of the "model storm" the system was supposed to protect against. That went against the congressional mandate to protect against the most severe threat that could be expected, van Heerden said.

"Our research shows very clearly that the standard was changed, but the corps just kept going about its business as if nothing happened," van Heerden said.

Katrina, a Category 3 storm when it made landfall, fell far short of the expectation of the most severe hurricane.

In 1985, the head of the project ordered his staff to ignore an official reduction in the elevation of the land they were building on. That left levees and floodwalls as much as 2 feet lower than claimed.

"Had the walls been built as high as called for, the floodwalls in the Lower 9th Ward would have been overtopped for 1.5 hours, but instead water poured over them for 4.5 hours," van Heerden said.

That water scoured out deep trenches inside the floodwalls, contributing to their collapse.

Below-design walls and levees contributed to many of the more than 50 breaches the system sustained during Katrina, the researchers said.

The agency missed major engineering mistakes by subcontractors; those led to breaches including those on the 17th Street and London Avenue canals. According to the report, the decision that a thin layer of clay at the bottom of the London Avenue Canal could keep water from seeping into the sands below was based on incorrect calculation of a standard engineering formula.

"Had the corps caught that error - as it is supposed to - and required the work to have been done properly, in all likelihood the design would have been changed, which could have prevented this failure," van Heerden said.

"We found several stances where (better) designs were originally proposed - T-walls instead of I-walls - and then changed for no apparent reason."

The corps failed to maintain the system properly, including keeping pace with subsidence. Moreover, the agency ignored advances in engineering knowledge and technology that could have prevented the flood.

The system "was managed like a circa 1965 flood-control museum," the report states, pointing out that the corps made no improvements to account for well-known changes in elevations, sea-level rise or even gaps left in the system.

Paul Kemp, who was part of Team Louisiana as an LSU storm modeler, said he was "struck by the fact that the corps showed no sense of mission on this project, even though it was involved with it for more than 40 years."

Instead, the agency showed "absolute adherence" to obsolete standards - a 1959 model for the Standard Project Hurricane. And yet the corps seemed willing, Kemp said, to make other wholesale changes midstream, such as abandoning a proposal to install floodgates at the canals in the mid-1980s, which might have stopped the Katrina surge that broke through their walls.

"It looked like no one was really in charge," he said.

The report also calls for the state and Congress to hold "8-29 Commissions" for a full investigation of the disaster, passage of a "Katrina Recovery Bill" to ensure coastal restoration and flood protection are fully financed by the federal government, and more transparency on the part of federal and state authorities when discussing flood protection plans.

"Citizens of New Orleans were never told by those with both knowledge and responsibility just how vulnerable they were to flooding, or the public safety compromises made in designing and building structures," the report states.