Hurricane Isaac slashed Louisiana with bands of rain and powerful wind gusts as it made landfall late Tuesday in marshy Plaquemines Parish, 90 miles southeast of New Orleans. The slow-moving storm roared through the sparsely populated parish, pointing toward New Orleans, where it could provide the first major test of the costly flood-protection system built after the devastation of Hurricane Katrina.

The storm grew stronger over the warm waters of the Gulf of Mexico, swelling to Category 1 strength with sustained winds over 80 mph stretching 60 miles from its core. It is expected to dump as much as 20 inches of rain in some areas, and local officials were bracing for the possibility of lengthy power outages.

Some residents of low-lying Louisiana parishes heeded evacuation orders and fled to higher ground, though government leaders fretted that the storm was not being taken seriously enough. In New Orleans, where no evacuation order has been issued, many residents chose to stay put. As the storm made landfall to the southeast late Tuesday evening, most businesses were closing, but a few bars were still open in some spots, such as the French Quarter.

“Now is the time to hunker down,” New Orleans Mayor Mitch Landrieu urged late Tuesday. In a news conference, he decried “knuckleheads” who were splashing in the waters of Lake Pontchartrain, ignoring warnings to stay indoors.

Armed National Guard troops, activated by Louisiana Gov. Bobby Jindal, patrolled New Orleans streets and stood guard outside the Superdome, which became a squalid refuge and a source of national shame in the chaotic days after Katrina hit in 2005. Isaac was arriving exactly on the seventh anniversary of Katrina, a coincidence that forced the cancellation of memorial events and made New Orleanians remember the painful ordeal they had endured, even as they were waiting for another storm to hit.

Mistrust vs. hope

When storms come, Brenda Walker doesn’t place her faith in much. She counts on the pistols she keeps — one for each hand. And she trusts in her black-and-white pit bulls, Boo Boo and Ro Ro.

But the huge levee that rises a few steps from the property that her father bought in the 1940s in the Lower Ninth Ward is another matter. It’s been fixed and raised and spruced since it gave way during Katrina, carrying away her father’s house and so many others. But still Walker wonders. “I don’t trust nuthin,’ ” she says between drags of a cigarette on the porch of the snug new house she built there.

The ancient mistrust of the Brenda Walkers of this city — a skepticism born of decades of flooded streets — is, however, coming face to face this week with a countervailing sense of optimism among other residents, a hope that one of the more ambitious engineering projects in recent U.S. history could come close to making this jewel of a city watertight.

In the past seven years, crews have laced together an intricate system of flood walls, levees, gates and pumping stations — essentially a massive plumbing operation designed to block storm surges from entering the city and to capture and pump out the rainwater that fills its streets. The $14.5 billion project is not quite completed, but federal officials were still expressing confidence that the city would be protected. The project is studded with superlatives touted by the Army Corps of Engineers: the world’s largest drainage pumping station and the biggest surge barrier of its kind in the world, to name a few. Now the question is how it will perform.

“It’s still an essentially unproven system,” said John Lopez, a costal scientist with Lake Pontchartrain Basin Foundation, a nonprofit coastal preservation group. “This is a very complicated system. It has to be operated correctly.”

If Isaac remains a Category 1 hurricane, it will offer a “modest test, not a severe test,” Lopez said.

Tim Doody, president of the Southeast Louisiana Flood Protection Authority, dismissed Isaac as a mere “quiz,” rather than a test. But at least there’s something to measure, with the new, synchronized network of projects aspiring to replace the patchwork of levees, flood walls and drainage pumps that had been cobbled together over the decades.

“Prior to Katrina, we had a system in name only,” said Rene Poche, a spokesman for the Army Corps of Engineers in New Orleans. “Now, we have a true system.”

The system is built to withstand a storm that would occur once in every 100 years. Doody doubts that the “100-year protection” underlying the current design will be adequate over the long haul. “It’s good enough to meet [Federal Emergency Management Agency] guidelines . . . it’s good enough for insurance purposes. But it’s not good enough.”

The storm has been drawn into the political sphere because it coincides with the Republican National Convention, which was delayed a day because Isaac originally seemed headed for the convention site in Tampa. Jindal, who canceled his trip to the 2008 Republican National Convention because of Hurricane Gustav, is once again skipping his party’s convention — and a coveted speaking slot — to oversee the response to Isaac.

Aboard Air Force One on Tuesday, White House press secretary Jay Carney told reporters that President Obama continues to receive briefings about Isaac, even as he heads to campaign in the Midwest. “The president’s focus is on making sure that FEMA and the rest of the federal team is doing all it can to support potentially impacted states,” Carney said, adding, “He takes the potential effects of this storm very seriously.”

‘Katrina exposed mistakes’

In Louisiana, dozens of local officials — including Landrieu, sheriffs and parish presidents — have crowded behind lecterns over the past few days, pledging interagency cooperation and a speedy response. The serial news briefings seemed to be an effort to prevent comparisons to the Katrina response, when city, state and federal officials were viewed as woefully uncoordinated during a storm that cost about 1,800 lives. “We’ve pretty much got stuff that we wanted to get in place ahead of the hurricane,” said FEMA Administrator Craig Fugate, who traveled Tuesday to Alabama and Mississippi to assess his agency’s storm preparations.

Fugate and other officials once again urged residents in the path of the storm to take the necessary precautions. “This is a very large storm. It’s going to take a long time for it to come through the area,” he said.

“The levee system that was here before Katrina arrived was an improper design, and that’s why it failed. Katrina exposed mistakes,” said Sandy Rosenthal, founder of, a nonprofit group whose goal is to educate people on the reasons that New Orleans was so vulnerable. “Did those mistakes get fixed? That’s the question. The answer is, we think so.”

Rosenthal does have lingering quibbles with the Corps of Engineers about its work in the wake of Katrina — particularly temporary pump stations on three outfall canals that have yet to be replaced with permanent ones — but mainly she thinks the new levee system is a sound one. “We believe they have removed the possibility of catastrophic breaching,” she said.

Harold Kokes and his wife, Sandra Bisgaard, felt confident enough that they repaired their home, which stands at what he calls “the toe of levee,” just a few blocks down the street from the spot where the levee protecting the 17th Street Canal burst open. During Katrina, the house drowned in a spreading, putrid lake of 12-foot-high floodwater. “I would not have moved back if the Corps had not done what it did,” he said in reference to the repairs and upgrades.

Even in this comfortable, middle- and upper-middle-class neighborhood, there are still houses boarded up and vacant. A short walk from the home that Kokes and Bisgaard share, two young children skip through puddles accumulating on a large concrete foundation, the house that once sat on it scraped away and long gone.

The children’s mother, Dora Cullen, strolls past that forlorn slab almost every day on the way to a small home she rents nearby. But when she does, she doesn’t see blight. She sees possibilities.

“Wow,” she often says to herself. “That would be a really nice double lot for a house.”

James Ball and Ed O’Keefe in Washington and Amy Gardner in Ames, Iowa, contributed to this report.