It is early evening in New Orleans and a small crowd has gathered where, 10 years ago, the levee broke and flooded the Lower Ninth Ward. For local residents, this is Ground Zero.

The sun is beating down hot and hard and people stand in the shade of a canopy installed for the occasion. Soon a plaque will be unveiled to commemorate the moment that changed their lives for ever.

Al "Carnival Time" Johnson takes to the little stage in a pale blue suit and a gleaming golden crown. He sings about the home a few blocks away that he lost on that day.

2349 Tennessee Street …
I loved it and it loved me.
The home I loved is not there anymore.
That's why I'm calling it, I'm naming it, Lower Ninth Ward Blues ...

Through the speeches that follow there's a common refrain. Al Johnson's home and the countless others like it were not destroyed by a storm. This was a man-made failure of man-made levees, and it never should have happened.

But the man-made failures didn't end there. That's what gnaws at many gathered this evening - and plenty who stayed away.

Robert Richardson holds a placard: "OUR ROOTS RUN DEEP HERE." He's right: his family first moved to the Lower Nine in 1953, along with many other working-class blacks in the postwar years.

Robert's roots were nearly severed, not by the flood but by the long battles that followed. "It was a fight," he says. "They wanted to tear everything down. Just cleanse the whole area - you know, like ethnic cleansing."

Difficult road home

It sounds like an outlandish claim, but look at the data and you can understand why people feel that way. Ten years after the flood, the population of the Lower Ninth Ward - an overwhelmingly black neighborhood - is still more than 60 percent below its pre-Katrina level. And New Orleans as a whole has lost tens of thousands of African-Americans. If the city has been "reborn" as so often claimed - it's been reborn without them.

Common Ground Relief was one of the first organizations to join the fight, mobilizing thousands of volunteers to help people gut their ruined homes. The majority of homeowners in the Lower Nine had no flood insurance, leaving them dependent on outside help.

Director Thom Pepper explains. "People had felt safe. They were told that this community was protected by federal levees. Insurance companies were telling them that if you lived more than 1,000 feet from a levee, you didn't need flood insurance."

But they were not safe - and those who survived the flood were unable to return for years. They dispersed in their thousands - some to other parts of New Orleans, some to other cities, some to other states.

The government held out the promise of return with the "Road Home" program. It was billed as the largest effort of its kind in US history - a $10 billion fund aimed at helping people across Louisiana to rebuild their homes.

Segregation, discrimination

But for Lower Niners, the "Road Home" was strewn with hurdles. Some no longer had the title to their properties - which had been passed down to them over generations - hampering their ability to make a claim. Others were overwhelmed by the bureaucracy. But the greatest barrier was the formula underpinning the Road Home program itself.

Cashauna Hill of Greater New Orleans Fair Housing takes up the story. "Our counselors began to notice that white homeowners in white neighborhoods were slated to receive larger grants than those for black homeowners in African-American neighborhoods - even when their homes were of similar age and similar square footage."

The reason: Payouts were based not on the cost of rebuilding, but on the value of the home before Katrina hit. Besides being irrelevant to the task at hand, the formula ignored the fact that US property values are profoundly affected by race.

"Because of this country's history of government-sanctioned and sponsored racial segregation and discrimination, African-Americans' homes in African-American neighborhoods are valued lower than the homes of white people in white neighborhoods," Hill explains.

In 2008, GNO Fair Housing filed a lawsuit claiming racial discrimination. It was successful - up to a point. In 2011 the government settled, providing an additional $60 million in funds. For some, it made the difference. For others, it still wasn't enough - or it was simply too late.

Six years had passed. Those who had grown roots elsewhere could not face severing them again. For local activist Vanessa Gueringer it was part of a pattern: "We don't want you, and we're going to make every step of your return as difficult as we can make it."

'Affordability crisis'

The government has now announced further changes to the program - changes welcomed by GNO Fair Housing. But a full 10 years on, will any more people really come back? Gueringer: "People are not coming back that have not come back. I have many, many friends that are doing well somewhere else, whose children are attending excellent schools, they have good jobs."

Good jobs that are hard to find in New Orleans - especially for African-American men. Only 48 percent of black male New Orleanians are currently in employment. This contributes to another part of the post-Katrina battle: a chronic "affordability crisis" in New Orleans' rental market that Cashauna Hill says African-Americans are bearing the brunt of.

Rents have soared over the past 10 years, partly triggered by Katrina. As Hill explains, the flood left around half of the city's rental units severely damaged, taking many off the market. Then the city demolished the four largest public housing developments in Katrina's wake - wiping thousands of homes off the map.

Instead of building new public housing, the city provided tenants with vouchers to pay rent on the private market - where GNO Fair Housing has found they are the victims not just of market conditions but of rampant discrimination.

"It is perfectly legal for housing providers to discriminate against voucher holders," Hill says. Given her estimate that 96 percent of voucher-holders are black, it looks like state-sponsored racial discrimination.

Black New Orleanians higher up the income scale are not immune. Hill cites a study in which 44 percent of well-off African-Americans found themselves excluded from rental properties in more affluent neighborhoods.

The Lower Ninth Ward was never an affluent neighborhood. But in the postwar era it became not a place of poverty but of an aspirational black working class. Here, African-Americans could afford to buy a lot, build their own home, and pass it on to the next generation. In time, the Lower Nine had the highest homeownership rate in New Orleans.

Gentrification fears

Sustaining this tradition has been one aim of Brad Pitt's non-profit, Make it Right. It has built 109 owner-occupied houses near the site of the levee breach - designed by big-name architects right up to Frank Gehry.

The effect is striking if a little bizarre; on a Sunday afternoon architecture buffs idle around in their cars, peering out at the swooping rooftops. But the houses are pricey to build and Make it Right has long since opened up to newcomers as well as returnees

Tanya Harris of Make it Right - herself a pillar of the Lower Nine community - says that is just as it should be. "We have to be aware that our rebirth is going to encompass new people. We want to teach you the Lower Nine way of life when you come, but we welcome you."

But for many, that spells a dreaded word: gentrification. It is already rampant in many parts of the city - most notably in the Bywater and the Marigny, which border the Lower Nine to the west. There, chic new developments like the St Roch Market serve kale, craft beer and cold-brew coffee to the inevitable mustachioed hipsters - and epitomize the "rebirth" of New Orleans.

Quality of life

It feels a world away from the Lower Ninth Ward but a controversial development of condominiums at the former Holy Cross High School could be a taste of things to come. New infrastructure is acting as a magnet - from sports facilities to a fire station, in the past year the neighborhood has gained essentials it's been lacking for so long.

While that infrastructure is welcomed by Lower Niners, there's a nagging sense that it's not being built for them, but for the gentrifiers to come: for whites with resources, votes, and voices that are heard more than theirs ever were. For people replacing those whose "Road Home" was strewn with too many hurdles.

Vanessa Gueringer is bracing herself. "Once they inundate this neighborhood, they're going to demand that certain things take place here that's going to make their quality of life here and those of us who will be able to remain."

Gueringer's fear is that those who have managed to return will only find themselves priced back out of their neighborhood - either by rising rents or by hikes in property taxes.

It's a fear that if it comes, a rebirth of the Lower Nine - just like the rebirth of New Orleans - will be about other people's lives, not theirs.