Alda Ballard has lived in her Catharine Street brownstone since buying it with her husband in 1980 for $20,000. She's lived in the neighborhood for 70 years.

Like many Philadelphians, Ballard clings tenaciously to her memories of her Center City West neighborhood in its heyday, before things went bad, when houses became empty shells that eventually collapsed or were torn down to be replaced by lots overflowing with trash.

That period was bad, to be sure, but now her neighborhood is experiencing another wave that troubles her: an influx of new people who are younger, wealthier — and whiter.

For the past few years, people have been offering to buy her seven-bedroom brownstone. She feels besieged by strangers who view her home as a valuable commodity and her presence as a nuisance.

"They are always knocking on my door telling me they want to buy my house," she said. "Well, I am not selling."

The same goes for the several rental properties that she owns in the area. "I keep my rents low, nothing higher than $850. It's not easy with the tax increases, but you do the best you can."

It is part of her effort to provide a place in the neighborhood for black tenants who don't earn enough to pay more.

Ballard is not worried about having to move for now. But in neighborhoods all around the city, longtime residents express fear of being forced out of their homes as waves of wealthier residents move in and spur property values to rise dramatically — a process known as gentrification.

Those who study property values and other trends believe it is an established reality in neighborhoods like lower North Philadelphia, Francisville, Northern Liberties, Fishtown, Kensington, Fairmount, Center City West, Hawthorne, University City, Point Breeze and Grays Ferry, to name a few.

Home-sale prices in these neighborhoods, which circle the city's central business district, have skyrocketed since 2000. Some momentum was lost during the recession, but sale prices resumed their steady climb in 2010.

Gentrification is not new, of course. The change of a block or neighborhood from low value to high value, is "a natural phenomena that has been with us since Benjamin Franklin," said Carolyn Adams, a professor in the Department of Geography and Urban Studies at Temple University.

Also the neighborhoods affected by gentrification aren't always black. Kensington and Fishtown, for example, were traditionally blue collar white neighborhoods. And in San Francisco white middle class professionals are being shoved aside by higher income earners in the tech industry.

For the last half of the 20th century, many parts of Philadelphia were on a downward spiral as the city lost population and business.

Now, the tables have turned. The city's population is on the rise, growing by 58,897 to 1,547,607 from 2006 to 2012, according to the most recent census estimates.

Many of these newcomers are choosing to live in Center City and nearby neighborhoods that offer quick access to job centers. Although the collapse of the real-estate market and the recession slowed development, the pace is picking up now that the economy is on the mend.

Despite concerns over gentrification, the city can't afford to slow development. So, it must find ways to encourage growth while protecting long-term homeowners and creating neighborhoods that are economically and racially diverse.

It might be easier to achieve world peace.

Philadelphia is ranked as the ninth most racially segregated metro area in America based on an analysis of the 2010 Census. Many Philadelphians live in neighborhoods where a single racial group represents 75 percent or more of the population.

It also is one of the poorest cities, with 26.9 percent of residents deemed poor by federal standards.

While population is on the rise, homeownership is declining, dropping to 52.2 percent from 59.3 percent.

Thirty-eight percent of homeowners earn less than $35,000; and 40 percent of homeowners do not have a mortgage.

These challenges are formidable. And so the economic pressures created by rising home values and higher taxes feed the fears that longtime homeowners will be forced to sell because they can no longer afford to stay.

But Adams says there is little direct displacement due to gentrification.

"When housing specialists use that term, they really aren't talking about displacing people," she said. "They are talking about market pricing that makes it impossible for people who are looking to move into that neighborhood who cannot find an affordable unit. That really is more the dynamic of gentrification now."

Adams' academic explanation doesn't mean much to the relatively few longtime black residents remaining in Center City West. They feel differently.

In just 15 years, they've watched longtime friends and neighbors move away, and be replaced by mostly white well-to-do strangers.

Jerome Whack, the owner and operator of the 20th and Christian Street Pharmacy for 45 years, said his customers complain daily about the disappearance of affordable apartments in the area. They tell him of rent hikes they can't afford, landlords no longer willing to accept their federal rent vouchers, and of new owners who want them out.

The new renters are willing to pay $1,300 and up for renovated digs in old brownstones just a few blocks from trendy shops on Walnut Street and the entertainment venues that line South Broad Street.

Whack doesn't live in the neighborhood, but owns the building that houses his pharmacy as well as three other properties in the area. Like Alda Ballard, his real estate holdings are highly coveted by real estate speculators. Whack shows a pile of unsolicited offers sent through the mail.

EARNI YOUNG / Daily News Staff Jerome Whack, owner and operator of the 20th and Christian Street Pharmacy, did not want his face photographed as he showed off a pile of unsolicited offers to buy his properties.

Government's role

The market is one driver of changing neighborhoods, but larger policy directions, especially from the federal government, which often provides financing for redevelopment, also can play a big part. Universal Companies, founded in the 1980s by R&B music icon Kenny Gamble, has seen this first hand.

Gamble grew up in the neighborhood and returned in the late 1980s with the intent to rebuild the area as a mixed-income but largely black enclave.

It was not to be. Universal's affordable development projects depended on a complex web of federal, state and city financing, which took years to put together. Meanwhile, market rate developers were able to snap up properties and move forward at a much faster pace. A 1998 city survey counted 553 vacant buildings alone. By 2002, almost all had been redeveloped in some way.

Universal was able to build about 160 affordable rental units in the blocks between Broad and 18th streets, before real estate became too costly. It then partnered with the Philadelphia Housing Authority to build a mixed-income community of 249 units of low-rise rentals and for-sale housing on the site of the old Martin Luther King Housing Project, at 12th and Catharine streets. The renamed MLK Plaza, completed in 2011, was more than a decade in the making, and was PHA's first effort to include affordable workforce housing for middle-income buyers.

Daily News Graphic

The project was situated at the heart of Hawthorne, a neighborhood stretching from 11th to Broad streets and from Washington Avenue to South Street. By the time MLK was finished, the character of Hawthorne had changed and the housing was much more expensive.

That was the outcome HUD hoped for when it provided funding to redevelop the blighted public housing project under its HOPE VI program. The idea was to replace traditional public housing with a modern mixed-income community that would help revitalize the entire neighborhood by attracting private investment.

Hawthorne is not gentrified in the traditional sense, since there is room for everybody — renters and buyers— at all income levels.

Universal is now one of many developers who have their eye on Point Breeze, a gritty blue-collar neighborhood bounded by Washington Avenue and Mifflin Street and 25th and Broad streets. As of last spring, the city had approved 430 tax abatements for construction in the area. However, 1,097 vacant lots and buildings scattered throughout the neighborhood mean there is plenty of room for growth if the long-time residents and developers can come to terms on how it should be done.

One of the more vocal community advocates determined to maintain the diverse character of Point Breeze is Haley Dervinis, 32, a white professional who bought a renovated two-story rowhome on Annin Street in 2006 for $200,000. Eight years hardly qualifies the Drexel University employee as an old-timer, but Dervinis is committed to maintaining a diversity that brought her to Point Breeze in the first place.

ALEJANDRO A. ALVAREZ / Staff Photographer Haley Dervinis, of the 1300 block of Annin Street in Point Breeze.

"Yes, I am white but I moved to a neighborhood that was appropriate for me in terms of my income," Dervinis said. According to Dervinis, she and her boyfriend were the first whites to buy on her block, but she doesn't see herself as an agent of gentrification. Nor is she waiting for the chance to sell her house for a whopping profit so she can buy a bigger house somewhere else. "I love my block. I love the people that live here," Dervinis said. Claudia S. Sherrod, executive director of South Philadelphia Homes, said she and other Point Breeze old timers feel their newer neighbors often show a lack respect for those who have called Point Breeze home for many years. "In many cases, these newcomers assume they are better because they may earn more money than we do and have rooftop decks and things that are not a part of our community," said Sherrod, who is black. She and her husband moved to Point Breeze and purchased a home in 1959. The city's challenges As if gentrification wasn't a big enough challenge, the city's new property tax assessment system, The Actual Value Initiative, has created further challenges. AVI is the city's attempt to catch up to increases in property values that were foregone during the real estate boom. Prior to AVI, properties were assessed at a percentage of their market value. Now property owners are facing tax bills based on market values that are double or even triple their 2013 assessments. The sticker shock is especially dire in gentrifying neighborhoods that have experienced the biggest spike in home sale prices. For example, Alda Ballard's brownstone was recently assessed at $420,000, vs. $27,100 in 2012.

“They grin and say hi, because they have been promised that we will be gone soon.” Jerome Whack, pharmacy owner

Long-time homeowners say they are being unfairly taxed while those who buy newly constructed or substantially rehabbed buildings enjoy 10-year property tax abatements on their structures.

"They are being incentivized to replace us," Whack, the pharmacist, said in reference to the whites moving into the area. "They grin and say hi, because they have been promised that we will be gone soon."

Philadelphia has put a handful of policies in place to provide property-tax relief for long-time property owners hit hardest by AVI. One of the programs is the Longtime Owner-Occupants Program, which provides a tax break for homeowners whose property assessments increase by 300 percent or more in the course of one tax year. There also is a Homestead Exemption that reduces the taxable value of qualified owner occupied homes by $30,000.

"We feel the people who held on deserve our support," said Council President Darrell L. Clarke. "If we had not done some of these AVI relief measures, a lot of people probably would be forced to sell their homes."

This year, Clarke, who also represents the city's 5th Council District, joined with six other Council members to spearhead passage of legislation to create 2,000 units of affordable housing in gentrifying areas. This will be more difficult than it was during the '90s, when the federal government funded a bevy of affordable housing programs. Over the past decade, federal funding has dried up and the city's Community Block Grant has been whittled to $49 million, compared to $85.5 million in 1996. Cities now mainly rely on Low-Income-Tax Credits to support development of affordable rental and for-sale housing. Council's plan would help projects take advantage of those credits, as well as money for the city's Housing Trust Fund, to build 1000 units each of rental and for-sale housing close to job centers.

Claudie S. Sherrod, of Point Breeze, is executive director of South Philadelphia Homes. (JESSICA GRIFFIN / Staff Photographer)