The federal agency that maintains the levees is aware of the risks. But Ricky Boyett, spokesman for the New Orleans office of the U.S. Army Corps of Engineers, said the corps is confident that South Louisiana river levees are in great condition, with improvements made since 2011.

“If there’s a silver lining going into hurricane season with the river this high for this long, we’re entering the hurricane season having done 200 inspections of the levee since February,” Boyett said.

Inspectors were looking for parked barges, stuck debris or other potential trouble, such as tire ruts or damage from feral hogs on grassy surfaces. They also looked for water seeping through, and for sand boils — spots where water tunneling below a levee seems to bubble out of the ground.

Concrete mats armor underwater areas likely to be eaten away by the river’s current, Boyett said. Sand boils get ringed with sandbags until the water pressure on both sides equalizes, stopping the flow. And because some permanent repairs can’t be made during high water, dangerous seepage gets stopgap coverage: About 63,000 large sandbags have been used since March on one 300-foot-long (91.5-meter-long) seepage area upriver of Baton Rouge, he said.

Even so, experts who study flowing water say there’s a risk the river could rise above the tops of some levees in the New Orleans area, if a hurricane pushes enough storm surge up the swollen river. The city’s levees held the river back in the great flood of 1927 and haven’t been topped since then, Boyett said.