The U.S. Army Corps of Engineers has made it no secret that its decisions regarding Dallas' ambitious plans to remake the Trinity River corridor with bridges, lakes and a toll road have been haunted by the ghosts of the victims of Hurricane Katrina.

Last week, in an extraordinary ruling, a federal judge in New Orleans showed why.

In a powerful, almost angry decision, U.S. District Judge Stanwood Duval ruled that the corps' mistakes, delays and long history of "monumental negligence" made it liable for much of Hurricane Katrina's devastation.

The threat of being held financially and even morally responsible for Hurricane Katrina – one of America's most devastating tragedies – has made the agency especially cautious when reviewing levees, experts who have studied the corps' flood-control efforts said. That's true even in places like Dallas, where the threat comes from a small river rather than storm surges in the Gulf of Mexico.

The judge's unprecedented ruling, which the corps is expected to appeal, pierces the once-invincible legal immunity the agency has enjoyed at least since Congress passed the Flood Control Act of 1928. U.S. taxpayers could be on the hook for billions of dollars as a result.

"This is a big deal. It has them scared," said Bob Bea, a professor of engineering at the University of California, Berkeley, whose testimony during the New Orleans trial was cited in last week's ruling. "The red flag has been waved. The total litigation exposure exceeds $3 trillion. ... This is undoubtedly going to encourage them to proceed more cautiously than they have in the past."

That caution has already been seen in Dallas, where lives and billions of dollars' worth of property are protected by aging earthen dikes along the Trinity River.

After routinely giving the Dallas levees high marks for years, the corps sent shock waves through the city this year when the levees flunked an important inspection, bringing work on key elements of the city's largest-ever public works project to a halt.

The levees are designed to protect Dallas against a flood so rare that experts say the chances of it occurring in any given year is just one-eighth of 1 percent. But in a report released in April, the corps' national flood-safety experts said it's not certain whether the levees could withstand storms similar to the ones that doused Dallas as recently as 1990.

The levees here have never failed, but if they did, downtown Dallas could be inundated with floodwaters.

In Katrina's wake, Congress passed the National Levee Safety Act of 2007, and among other things it set up a national levees safety commission. That commission has begun crafting national standards for all the levees the corps oversees and has been responsible for much more vigorous application of the corps standards.

Kevin Craig, manager of the corps' Trinity River levee efforts, said Monday that since Katrina, the corps has tried to establish more uniform levee safety standards across the country.

"It's not necessarily one event that has caused anything," he said. "But as we learn more, we want to standardize the process nationally so that when you see a rating on a levee, there is a consistency with regard to the severity of the issue, and the risk associated with an issue. The standards are becoming more consistent."

One result of that approach has been that levees that for years had been seen as acceptable began to flunk inspections, not just in Dallas but in California and elsewhere.

Jeremy Arrich, who oversees levee inspections for the state of California, said more than 100 local entities share responsibility for maintaining 1,600 miles of levees near Sacramento. Before Katrina, levees associated with only four to five of them would fail in a typical year.

"Once we applied more strictly the standards set by the corps, we found that there were upwards of about 50 percent of the local entities receiving unacceptable ratings," he said. "The pressure came from the corps to implement the standards that have always been in place."

Last week's 156-page ruling helps suggest why the corps' approach has become suddenly more stringent.

"It is the Court's opinion that the negligence of the Corps ... was not policy, but insouciance, myopia and shortsightedness," Judge Duval said. "For over forty years, the Corps was aware that the levee protecting Chalmette and the Lower Ninth Ward was going to be compromised. ... The Corps had an opportunity to take a myriad of actions to alleviate this deterioration ... and failed to do so. Clearly the expression 'talk is cheap' applies here."

Duval's ruling also demonstrates that many of the issues raised in Dallas are ones that were in play for years leading up to the 2005 tragedy in New Orleans.

The corps has concerns about trees planted along the Trinity River toll road, worries about overgrown vegetation in the inspection report issued this year, and has overarching concerns that the soil composition could spell disaster – all of those issues played a role in the collapse of the levees in New Orleans, according to the ruling by Duval and experts who have reviewed the case.

And they are showing up in cities across the country, where concerns over levee safety have mounted significantly since Katrina, Bea said.

He said his team has traveled to the site of other troubled levees, and found the corps dealing with nearly identical concerns there.

"What we found was the same discouraging mess that we had found in New Orleans," he said of a trip taken last year to inspect levees that had failed in Illinois and Missouri. "I arrived there expecting to find real levees. After all, the Mississippi River has been around for a long time, and I thought the engineers for the corps and their colleagues had learned to build proper levees. Boy, were we wrong."

Even an issue apparently as minor as the dust-up two years ago over whether the trees would be permitted along the Trinity River toll road has its roots in New Orleans, Bea said.

"They got pasted in New Orleans because of those trees," he said.

When the hurricane blew over trees planted on the protected side of the levees, they left holes as big as 15 feet wide and 10 feet deep. "That opens up a big hole, and what you have done is shortened the distance the seepage must travel" to breach the levees.

The corps made big mistakes over the years leading up to Katrina, said University of Texas at Dallas President David E. Daniel, a civil engineer who was chairman of a national panel of civil engineers who reviewed the failure of the levees.

"The corps did not place the health and safety of the public at the top of their agenda," Daniel said Monday. "Their designs were not safe enough. So we certainly would hope that they are being more deliberate now."

Daniel said he has not followed the Trinity River levees' problems closely enough to know whether the corps has become so cautious that it is unfairly slowing down the toll road, the bridge or the parks.

But he said it's easy for residents, in both Dallas and New Orleans, to overlook a potential for disaster. Catastrophe isn't always the first thing Dallas residents think of when they view the usually docile Trinity River.

"But I can speak to another parallel [between the situation here and in New Orleans]," he said. "Even in New Orleans these devastating hurricanes of the Katrina type are extraordinarily rare. Decades go by with nothing particularly serious happening. It lulls you into a false sense of security, until that extreme event hits."

A federal court ruling taking the U.S. Army Corps of Engineers to task for its work on the levees in New Orleans prior to Hurricane Katrina reveals some parallels and some differences with the situation in Dallas.

SIMILARITIES

Trees: The corps was criticized after Katrina for having permitted trees to grow along the levees. Since then, it has been rigid in insisting no trees be planted along the Trinity River toll road and has required the removal of other trees already planted within the levees.

Soil: The ruling cites evidence that the corps knew for decades that the presence of permeable soil meant that New Orleans' flood risk would increase over time. But proper steps to safeguard against that were not taken. In Dallas, concerns about the soil composition beneath the levees have prompted the corps to order that the city spend millions to test whether the levees' soil is too sandy.

Competing interests: The ruling faults the corps for placing too much emphasis on improvements designed to assist commercial shipping interests, allowing safety concerns to go unaddressed. In Dallas, critics have said city officials are too eager to complete its toll road, bridges and other amenities in the face of worries by the corps.

DIFFERENCES

•The flood risk in New Orleans, situated below sea level within reach of the Gulf of Mexico, is obviously much different than the flood risk in Dallas, where heavy rains could propel the Trinity River over the levees.

•The judge's ruling that the corps must pay damages to Katrina victims hinges on a legal distinction that is unlikely to be relevant in Dallas. That means that even if the corps were to be blamed for a future flooding catastrophe, it is highly unlikely it would be held legally liable.

•In New Orleans, Hurricane Betsy devastated parts of the city as recently as 1965, after major components of the current flood protection system had been completed. Dallas' worst flood occurred in 1908, before the levees here were constructed.