Engineers say it will be weeks and possibly months before the flood waters in New Orleans recede completely.
Officers with the U.S. Army Corps of Engineers have given different estimates, with one officer, Colonel Richard Wagenaar telling the Los Angeles Times that draining the city may take half a year.
Army engineers said some New Orleans neighborhoods were under six to nine meters of water on Wednesday.
The low-lying city became inundated after water from Hurricane Katrina spilled over or broke levees designed to keep the city dry.
Engineers say flood levels have stabilized for now. They hope to speed the draining process by punching holes in certain levees so the water will flow out of the city.