(CNN) -- Calling the ruling "huge," New Orleans Mayor Ray Nagin on Thursday reacted to a federal judge finding the U.S. Army Corps of Engineers' failure to maintain a shipping channel led to catastrophic flooding during Hurricane Katrina.
Nagin said he hopes the court decision will "open up the floodgates" for others to file lawsuits against the federal government, including his Louisiana city.
However, he acknowledged it's likely the federal government will appeal Wednesday's ruling.
Department of Justice spokesman Charles Miller said in an e-mail the government is reviewing the decision and has made "no determination as to what future steps it would take in this matter."
U.S. District Judge Stanwood Duval Jr. ruled that the "negligence of the Corps" by failing to maintain the Mississippi River-Gulf Outlet waterway "was not policy, but insouciance, myopia and short-sightedness."
"For over 40 years, the Corps was aware that the Reach II levee protecting Chalmette and the Lower Ninth Ward was going to be compromised by the continued deterioration of the [waterway]. ... The Corps had an opportunity to take a myriad of actions to alleviate this deterioration or rehabilitate this deterioration and failed to do so. Clearly, the expression 'talk is cheap' applies here."
Duval issued the ruling in a lawsuit brought by six plaintiffs affected by the 2005 hurricane, who alleged the Corps of Engineers was liable for damages. The judge ruled against one couple, who lived in New Orleans East, but awarded the others, from the Lower Ninth Ward and St. Bernard Parish, damages ranging from $100,000 to $317,000.
Nagin said he had thought the ruling was a long shot. "This was a surprise but a pleasant one," he said.
The decision applies not only to the six plaintiffs, attorney Pierce O'Donnell said, but also to some 100,000 homes and businesses in St. Bernard Parish and the Lower Ninth Ward. Under the precedent set by Duval's ruling, they too will be entitled to compensation, O'Donnell said.
At a news conference Thursday, Craig Taffaro, president of St. Bernard Parish, said, "It's a bittersweet victory in the sense that yes, we are at the table, yes, we are grateful for the judge's ruling and for the legal team to deliver us to this point, but what a shame that we had to go through such devastation and destruction to get here."
At one point a Category 5 hurricane, Katrina had weakened to a Category 3 storm with top sustained winds of 127 mph when it made landfall on the morning of August 29, 2005, between Grand Isle, Louisiana, and the mouth of Mississippi River. Its winds were only slightly diminished when it passed over more populated coastal areas hours later.
More than 1,800 people died in the storm, including nearly 1,600 in Louisiana. In New Orleans, the city's levee system failed and widespread flooding occurred.
Overall, the storm damage covered more than 90,000 square miles and displaced nearly 300,000 people, causing more than $81 billion in damage.
Ivor van Heerden, a researcher who warned of the potential for catastrophic damage from a hurricane, said the ruling is "total vindication for everybody who was involved."
"I think he's called a spade a spade," van Heerden told CNN by phone. The former deputy director of the Louisiana State University Hurricane Center said the university fired him because of the investigation he led into the levee failures. The probe put much of the blame for the disaster on the Corps of Engineers.
He alleged Thursday that the university blocked him from being an expert witness in the case, but said he "put together a lot of the science" and reviewed the defense's explanation to find the holes.
"Hurricane Katrina in New Orleans was a manmade catastrophe with a hurricane trigger," he said. "I saw the suffering of the people in New Orleans. ... Finally there is the potential of compensation."
He said he intends to file a lawsuit against LSU, which he said has to pay him through the end of his contract, which ends in May.
LSU did not immediately return a phone call seeking comment Thursday.
CNN's Ashley Hayes contributed to this report.