Large areas of New Orleans were flooded by Hurricane Katrina
A US judge has ruled that negligence by the US Army Corps of Engineers led to massive floods in parts of New Orleans as Hurricane Katrina struck in 2005.
The court upheld complaints by six residents and a business against the Corps over its maintenance of a navigational channel.
They were awarded damages totalling $720,000 (£431,000), and the ruling could lead to thousands more claims.
About 80% of New Orleans was flooded by Hurricane Katrina.
More than 1,800 people died on the US Gulf coast in the devastating storms.
The Corps is responsible for maintaining a system of canals and earthworks that protect New Orleans from storm surges.
US district judge Stanwood Duval ruled "negligent failure" to maintain the Mississippi River-Gulf Outlet - a shipping channel - had led to flooding in the city's Lower 9th Ward and nearby St Bernard Parish.
However, he said the Corps had not been responsible for flooding in eastern New Orleans.
Government lawyers have argued the system had been overwhelmed by the hurricane and that levee breaches could not be blamed on the channel alone.
In his 156-page ruling, Judge Duval said he believed it was the failure to shore up the outlet that "doomed the channel to grow to two to three times its design width" and "created a more forceful frontal wave attack on the levee".
It was the first time a US court has found the federal government directly responsible for some of the damage caused by Hurricane Katrina.
The government can appeal against the ruling. US justice department spokesman Charles Miller said it would review the judge's ruling before making a decision on how to proceed.
Correspondents say that, if upheld, it could set a precedent for thousands more flood victims to sue the government for damages.