NEW ORLEANS (AP) — When Hillary Clinton visits New Orleans on Saturday in an effort to shore up support among black voters, she will be doing so in a city that is hanging on to a 30-year black majority by its fingernails.

Since Hurricane Katrina struck in August 2005, the black population here has plummeted by 57 percent, while its white population fell 36 percent, according to census data. Blacks are now roughly 58 percent of the post-Katrina city compared to the dominate 67 percent they comprised before the storm.

Facing the most viable black candidate in the nation’s history in Sen. Barack Obama, Clinton won 9 percent of the black vote in the New Orleans area, 16 percent in Southern primaries to date, and 18 percent in primaries outside the South, according to exit polls conducted for The Associated Press and television networks.

Clinton is scheduled to speak at ‘‘The State of the Black Union,’’ a symposium organized by broadcaster Tavis Smiley, who says he is also focusing attention on the state of black New Orleans.

‘‘New Orleans is a sort of municipal metaphor for two things, for the possibility of renewal and the possibility of revitalization,’’ said Smiley on Friday. ‘‘On the other hand, it is a municipal metaphor for maltreatment that so many people of color receive in America.’’

Other speakers at the event will include the Revs. Jesse Jackson and Al Sharpton, Louisiana Lt. Gov. Mitch Landrieu, Mayor Ray Nagin, Cornel West, a Princeton University professor and writer, and U.S. Rep. Maxine Waters of California and District of Columbia delegate Eleanor Holmes Norton.

The event enlisted some 1,000 volunteers who worked daylong beautification projects in some of the hardest hit parts of New Orleans, which overall has seen 65 percent of its population return, according to a local demographer who uses utility hookups to offer the most detailed population numbers. The sweat equity of such volunteers has made a difference citywide, but some black enclaves are a fraction of what they were, and others see their very existence threatened.

According to demographer Greg Rigamer, the Lower 9th Ward has seen only 9.9 percent of its population return, making it the neighborhood with the fewest residents so far despite frequent visits by politicians and notables who outlay their rebuilding strategies at the levee walls there.

A traditionally black neighborhood within the boundaries of the Lower 9th, Holy Cross, has fared better with a 37 percent return. Preservationists have worked to rebuild the area, which is a federally declared historic district.

New Orleans East, a sprawling area near the city limits that includes the black upper middle-class enclave of Eastover, has nearly kept pace with the overall return, with about 60 percent of its residents home.

But New Orleans has still become a place where events like last week’s NBA All Star Game contrast with a tent city of about 200 homeless people living along a road to the arena. Rent has hovered at 40 percent above its pre-storm level, while to the dismay of housing activists, 4,500 public housing units are set for demolition.

Monique Harden, co-director of the public interest law firm Advocates for Environmental Human Rights, believes U.S. politicians are no longer paying attention. Harden went to Geneva this week to take her case to a United Nation’s committee.

‘‘People who are displaced have the right to voluntarily decide whether they want to come back,’’ she said, citing U.N. standards for displaced ethnic groups. ‘‘The response of our national government has been to create conditions that won’t allow that to happen in New Orleans.’’

Some demographers point to class, not race, as the primary factor in the post-Katrina shape of the city. A September 2007 study by The Brookings Institution, which used census figures, found that post-Katrina New Orleans was not just whiter, but older, with fewer renters and a more-educated population.

Rigamer’s numbers bear that out, but also raise the race question. Affluent areas are fully recovering and even flourishing; but they are also predominantly white. The Garden District has seen 107 percent of its population come back, the French Quarter 103 percent, and a hipster neighborhood called The Marigny has a 100.3 percent return rate.

Smiley said he will press Clinton, the only presidential candidate to respond to his offer to attend the event, on her plans for New Orleans. But he still saw hope in the volunteers who started their work a day before Clinton’s arrival.

‘‘They were young and old, educated, not so educated, black, white, brown,’’ he said. ‘‘It was a beautiful thing to behold.’’