Hurricane Isaac sidestepped New Orleans on Wednesday, sending the worst of its howling wind and heavy rain into a cluster of rural fishing villages that had few defenses against the slow-moving storm that could bring days of unending rain. Isaac arrived exactly seven years after Hurricane Katrina and passed slightly to the west of New Orleans, where the city's fortified levee system easily handled the assault. The city's biggest problems seemed to be downed power lines, scattered tree limbs and minor flooding. Just one person was reported killed, compared with 1,800 deaths from Katrina in Louisiana and Mississippi. But in Plaquemines Parish, a sparsely populated area south of the city that is outside the federal levee system, dozens of people were stranded in flooded coastal areas and had to be rescued. The storm pushed water over an 18-mile levee and put so much pressure on it that authorities planned to intentionally puncture the floodwall to relieve the strain. President Barack Obama declared federal emergencies in Louisiana and Mississippi late Wednesday, according to a statement from the White House. The disaster declarations free up federal aid for affected areas. By mid-afternoon Wednesday, Isaac had been downgraded to a tropical storm. The Louisiana National Guard wrapped up rescue operations in Plaquemines Parish, saying they felt confident they had gotten everyone out and there were no serious injuries but would stay in the area over the coming days to help, according to a National Guard spokesman.