In 1955, Philip and Nathan Seltzer broke ground on one of the country's first business parks, just off the Pennsylvania Turnpike in Fort Washington. At the time, sprawling corporate campuses were thought to be the workplace of the future.

But over the years, the Fort Washington Office Park, like many of its peers, showed its age, struggling to attract and keep tenants, a problem compounded by persistent flooding.

Now, with the help of local officials, the office park is enjoying a second life.

In 2017, Fort Washington leased the most net office space across Philadelphia — 214,000 square feet —  according to Jones Lang La Salle, the real estate firm.

The park has already attracted Life Time Inc., a 130,000-square-foot high-end health club. Future plans include a work, play, and live community of offices surrounded by restaurants, a hotel, a library, and apartments for 1,200 people.

JLL forecasts nationally that the 14.9 percent office vacancy rate will rise in 2018 and 2019 — a number that includes tech companies, which have been driving the market's leasing activity. Meanwhile, in Fort Washington, the office vacancy rate, about 16 percent in late 2017, is declining (in the Philadelphia suburbs overall, the office vacancy rate is 13.4 percent).

Aon Affinity, TruMark Financial, Lincoln Financial, and Ashfield Healthcare have all moved in.

To attract tenants back to the once-thriving office park, Upper Dublin Township first had to face its flooding.

"We have had cars trapped in storm water," said Rick Barton, the township's zoning officer. "People had to be rescued by the fire company." Businesses left and in 1989 an employee crossing the office park during a heavy rainstorm was swept down a drain and died. URS, the engineering firm, estimated that flooding, on average, caused about $3.7 million in damage annually, according to its 2010 study.

The flooding "sealed in our mind the need to do something," said Ira Tackel, president of the township's Board of Commissioners. Upper Dublin depends on the office park's success. It provides about 16.5 percent of the township's revenue and 10.5 percent of its school district's funding. In 2006, the township commissioned a $620,000 federally funded study to investigate solutions to the park's storm-water and transportation challenges. After $11 million in state and county-funded grants and $3 million of the township's funds, the park now benefits from two damlike structures designed to lessen the impact of future storms.

"Thus far, although we haven't had a 100-year flood that we've had in the past," Tackel said, "we've had some significant rain events, and the flood retarding structures have done what they're supposed to do"

Overall, the first phase of revitalization, including the reconstruction of two bridges, is estimated to cost $38.7 million, with more than 17 percent coming from the township. For its efforts, Upper Dublin recently won a Governor's Award for local government excellence in promoting economic revitalization.

Today, increases in occupancy and rental rates in Fort Washington are largely due to "investment in office assets and retail amenities," said Lauren Gilchrist, JLL Philadelphia's research director.

Real estate investors, such as Kairos, have transformed properties like Apex Fort Washington at 600 Office Center Drive into "Class A" properties, attracting new tenants and raising rental rates. Apex is home to Nutrisystem's corporate headquarters (and its 600 employees), which selected the office park in part for its proximity to the turnpike.

The Seltzer brothers, who headed the Delaware Valley Industrial Properties, purchased the office park's land back in 1947. "At the time, a lot of manufacturing that was in Philadelphia [was] done in multistory buildings," said Rick Seltzer, Philip's son, who once worked at the office park and is now a commercial real estate consultant. "They thought the idea of putting it on one floor would facilitate communication."

The brothers believed the set-up would also be attractive to employees who wanted less expensive parking, Rick Seltzer said.

Initially, Fort Washington residents needed convincing. "People imagined smokestacks," he said. Despite some opposition, Honeywell, the park's first major resident, set up shop in 1955 and remains today.

Louise Mozingo, an environmental planning professor at the University of California at Berkeley, said that, nationally, tight urban conditions, congestion, and racial tensions pushed companies out of cities in the 1950s. Increasing funding for highways, better expansion opportunities, and cheaper parking made the suburbs attractive.

"[Even] Suburban housewives are given employment opportunities," Philip Seltzer told the Inquirer in 1964, "close enough to their homes that they can beat their husbands [home] from work."

Back then, there was no Clean Water Act or a National Environmental Policy Act to discourage construction in a floodplain — or stringent regulation of the use of concrete, which can cover soil essential to absorbing water during severe storms.

But "wild overbuilding of office parks in the late 1980s" catalyzed the suburban office park's decline, said Mozingo. That's when the Seltzers began selling off parcels of the office park's properties, which are almost all owned privately today. In 2016, the township created a new municipal authority to manage the park collectively.

In 2013, the township tried to spur less vulnerable, and more diverse, development through a transferable development rights program. It offered development "credits" to property owners in the park's vulnerable floodplain who moved out to repurpose (or construct) multi-use buildings in other parts of the area. These credits could also be sold.

"We had developers that were ready and willing to buy," said Barton, "but no one was willing to sell credits." Last fall, the township started the process of rewriting its zoning code, which will replace the credits program, with the help of Thomas Comitta, a landscape architect.

As revitalization efforts continue, the township anticipates spending at least $34 million more on improving surrounding trail connections, installing pedestrian lighting, and further improving storm-water management, according to Graham Copeland, the township's economic development expert.

To further diversify the park, the township purchased a new $5 million, 65,400-square-foot building for its new library.

There are plans for a new ramp that provides direct access into the office park from the turnpike's toll plaza and a Cross County Trail that's better connected to the Fort Washington SEPTA station. The hope is to encourage more carpooling, public transportation use, biking, and walking. Now, 94 percent of the office park's employees drive to work alone, according to the township's recent transportation demand management plan.

As Comitta thinks about the future of Fort Washington, he remembers how his father used to walk to his factory job in Manayunk. "In 2038, which is just 20 years from now, we will be back to the Manayunk model," he said.