Hurricane Isaac has come and gone. Floodwaters in southeastern Louisiana are receding. For Chris Gilmore, it's time to take initial stock of how his segment of a $14.5-billion, 133-mile defensive wall of earth, steel, and concrete preformed in the first real-world test of post-Katrina improvements in flood protection for New Orleans and portions of surrounding parishes.

Isaac was a minimal hurricane when it made landfall overnight Aug. 28-29. But its large size and excruciatingly slow motion – at one point stalling for hours over the southeastern part of the state – built a surge whose height here at St. Bernard Parish, estimated at between 14 and 15 feet, rivaled the height of the surge Katrina delivered.

The view from the top of the levee reveals large patches of deadwood debris lying along the levee's base like so many casualties of a siege assault. Behind the levee and the new pair of massive steel floodgates that close across the four lanes and center median of Louisiana State Road 46, boats on trailers, RV trailers, and even trailers from 18-wheelers are parked along the highway shoulders. They belong to residents who live beyond the levee and who sought its protection for their hard-earned assets.

So how did this segment hold up? "It looks really good," pronounces the US Army Corps of Engineers' Mr. Gilmore, senior project manager for the St. Bernard Parish portion of the federally funded upgraded flood defenses.

Indeed, so far the most significant levee damage has come from wild hogs, who root around for worms and insects after heavy rains. These "hog holes" will require quick attention. They can accelerate erosion of a levee's earthen base.

Although inspections are still under way, the initial reaction to the post-Katrina improvements to the levees, as well as to the pumping systems that drain water from New Orleans into canals that feed into Lake Ponchartrain, is that they worked as advertised.

The improvements, which include a 1.8-mile-long surge barrier that blocks a navigation canal that, seven years ago, funneled water into St. Bernard Parish and on into New Orleans, already have earned kudos from the likes of Gov. Bobby Jindal (R) and New Orleans Mayor Mitch Landrieu, a Democrat.

Officials with the Army Corps of Engineers and others have estimated that if the levee system had been at pre-Katrina levels when Isaac arrived, flooding in New Orleans would have been as bad as the flooding experienced with hurricane Betsy in 1965. Flooding was as serious then in places like the city's Lower Ninth Ward and in St. Bernard Parish as it was during Katrina, when rooftops often were the only refuges from rising water.

Little wonder then that, with Isaac, residents within the improved protective walls, floodgates, and surge barriers also have been singing the system's praises.

Gilmore recalls returning home Thursday night after four days of being "deployed" for Isaac: "I hadn't had a shower in four days. I hadn't really had a good meal in four days." After a shower and a square meal, "my BlackBerry rings. I'm thinking: 'Oh, man. Work.' "

Instead, he says, it's Kenny, a citizen who had attended all the public meetings the corps held as it was planning and adding improvements to the flood-protection system. As Gilmore recalls it, Kenny said, "Man, I just wanted to call you up and say I'm one of your biggest fans, I've supported you through the whole thing. Right now you've got a whole lot more fans than you did before."

With the first contracts for the project awarded in early 2008 and a scant 500 feet left to go, "it's really astonishing that this project has been built so quickly," adds Cindy Brown, who was born and raised in New Orleans and opted to evacuate as Isaac approached. "I'm very appreciative of that."

But residents outside the federally funded system didn't fare as well. Communities along the western edge of Lake Ponchartrain flooded, and then communities on the eastern edge flooded as Isaac's winds shifted.

Plaquemines Parish, which sports an 8-1/2 foot, nonfederal levee, experienced severe flooding that killed two people. Dozens had to be rescued, many of them people who ignored mandatory evacuation orders.

Indeed, standing atop the levee in St. Bernard Parish – an earthen embankment topped with a steel-and-concrete T wall to an overall height of 32 feet, anchored with steel H-beam piles up to 140 feet long, and stretching in each direction as far as the eye can see – Gilmore makes an inspection reminiscent of inspections royal engineers must have performed after a siege of a medieval walled city. Those outside the wall tended to work close to the land – or in southern Louisiana's case, close to the sea – with strong family ties to their spanning generations. When the invaders came, some could find refuge within the walls, others fled the area, while those who couldn't or wouldn't leave stayed and took it on the medieval chin.

Governor Jindal and US Sen. Mary Landrieu (D) of Louisiana are calling on the federal government to extend levee protection beyond its current boundaries. By some estimates, beginning in 2006 Congress authorized the US Army Corp of Engineers to spend as much as $800 million on levee improvements in some of the areas that experienced flooding as a result of Katrina. But lawmakers did not follow through with the appropriations, leaving the corps with an approval to spend money it didn't have.

And there are competing demands for the money. Clint Dawson, an engineering professor at the University of Texas at Austin and a member of the team producing the computer models of storm surge that helped inform the design of New Orleans's system, suggests that such proposals "have to compete with a lot of other projects that are perhaps equally important."

After hurricane Ike in 2008, it became clear that similar efforts at storm-surge protection would help some parts of the Houston area, another hub of the enegry industry. Tight funds are among the factors that have kept such projects from moving forward, he says.

Robert Whitman, a consultant for Entergy's Waterford 3 Nuclear Power Plant and a resident of La Place, La., on the shores of Lake Pontchartrain where flooding occurred, notes that beyond levees, improved zoning regulations, building-permit processes, and a reality check home buyers need to perform on a prospective house also play roles in reducing people's vulnerability to surge-related flooding.

With so much attention on steel-and-concrete projects, bolstering wetlands also remains key, adds Ms. Brown, who directs the Nature Conservancy's Gulf of Mexico Program. Without the wetlands, levees become a first line of defense against surge, rather than a last line.

Several restoration projects – also part of the Army Corps of Engineers' efforts – are on the books, she says.

And the funding stream may be somewhat more secure than money appropriated by Congress. The Restore Act, which President Obama signed in July, is expected to aim some 80 percent of an estimated $25 billion in fines against BP and other companies responsible for the Deepwater Horizon blowout at Gulf states.

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"This represents a real opportunity to get some of these restoration projects built," Brown says. "Time will tell exactly how the funds are spent. But that's one source of money folks are really banking on to make sure some of these projects all along the coast are paid for."

But more will need to be done. The price tag for coastal restoration in Louisiana alone has been estimated at as much as $50 billion.