New Orleans ? Heavy rains lashed the flood-prone city Monday, inundating areas that had only recently recovered from Hurricane Katrina and leading the Army Corps of Engineers to close a gate on a suburban canal where the waters threatened to top the walls.

After more than 8 inches of rain fell on parts of New Orleans by late afternoon, Mayor Ray Nagin shut City Hall early, and schools also closed. People were asked to stay indoors until the flood potential subsided. More rain was expected overnight.

Waist-high water in parts of eastern New Orleans soaked businesses, some of which had recently reopened after being damaged by 2005’s Hurricane Katrina.

All the city’s pumps were working properly, emergency preparedness officials said. Still, they urged motorists to stay off the streets to avoid creating wakes that could send water into homes and businesses.

Officials closed a gate on the Harvey Canal in Jefferson Parish; it was one of several in the area placed under new safety guidelines after Katrina’s waters breached two New Orleans canals, causing catastrophic flooding.