Make space for green space

What city has the space to accommodate a new park when land for development is at such a premium?

Had you been working in an office overlooking the Woodall Rodgers Freeway in Dallas, Texas, in the 1990s, you might have been puzzled by what was going on down below. Over the course of a decade, a huge section of the road was capped over. Where once you would have seen lanes of traffic, there were now trees, flower beds and pathways. By 2002, when the space opened to the public, people could be seen eating lunch by the fountain plaza, children running around on the great lawn. From nothing had come 5.2 acres (2.1 ha) of something. That something was Klyde Warren Park.

Delivered as a public-private partnership at a cost of $110m, it is the world’s largest suspended park infrastructure – maintaining the freeway below while supporting the weight of the greenery above. It is also a fundraising feat, drawing on a mixed pot of municipal bonds, highway and stimulus funds, and $50m in private donations to fund construction and supplement ongoing maintenance.

More remarkable still has been the impact of the park. One million people visited it in the first year it opened. On hot days the park is 1-9ºF cooler than the average for its zip code. A 2013 case study by the US Landscape Architecture Foundation projected it will generate $312.7m in economic benefit and $12.7m in direct tax revenue for the city. Adjacent commercial rents have increased 32% on average.

Klyde Warren Park is not an isolated story. Two years before it opened, New Yorker Robert Hammond was starting to think about how he could save an old elevated freight railway on Manhattan’s West Side. Hammond and his neighbour, Joshua David, launched a community campaign that would lead to what is now the city’s most popular tourist attraction after the Museum of Modern Art – the High Line. This park in the sky, some 7.3 acres (3 ha) in total, attracts more than 5 million visitors a year and has been central to the regeneration of the area. Built for $150m, it is predicted to generate $1bn in tax revenues to the city over the next 20 years.

Highway shrubbery

The success of the High Line and Klyde Warren Park has opened the door to green-space-strapped cities to think differently about their old infrastructure. One of those cities is Seoul. In May 2017, it opened Seoullo 7017 “the Skygarden” on an elevated highway that had been declared unfit for use three years earlier. Instead of demolishing the structure – which runs for almost 1km through the centre of the city – the mayor of Seoul, Park Won Soon, decided to run a design competition to recreate it as a public park. Dutch architect MVRDV won and was given just two years for design and construction.

Committing around £40m to a public space project is a hard sell for any mayor – 65% of the budget was spent on simply stabilising a structure that could have been knocked down. Kyosuk Lee, senior project leader at MVRDV, believes the firm won the competition for two reasons: “First, we saw the Skygarden not only as a park but as a pedestrian network, so we added new connections – stairs, lifts and escalators – to make it more accessible. Second, we worked out a way to put trees on top of the bridge.”

The mayor wanted a forest-like experience, but the bridge was so weak that if Lee’s team had applied the same planting methodology as on the High Line, it would have collapsed. So instead of layering soil everywhere, they found a way to concentrate it in the areas they needed it, which made the structure lighter. “We couldn’t afford to add any extra layers of paving. We reduced the depth of the floor to 25cm with a lighter, stronger concrete, and within that 25cm we added irrigation and drainage systems for the trees,” says Lee.

This innovative engineering enabled MVRDV to plant 24,000 plants and trees from 228 species and subspecies. “Normally, landscape designers in Korea use around 20 species,” says Lee. “We wanted to use the Skygarden as an exhibition space to show that all kinds of trees can survive in our system. Because if these species can survive here, they can survive being planted on rooftops all over Seoul.” One year on, Lee says that 95% of the species are surviving.

The Skygarden received 1.2 million visitors in the first year. Lee says there have been enquiries from developers interested in adding new connections to the bridge from their properties. Other benefits come down to priorities: one transport study found that the journey from one end of the old highway to the other on a busy morning is now 2.5 minutes quicker by foot than it would have been to drive.

Back in New York City, another ambitious park project is aiming to build on the success of the High Line, only this time it isn’t reusing transport infrastructure, but waste. For 53 years, the wetlands of Freshkills on Staten Island had been used as a municipal rubbish dump. Landfill from all over the city was piled high across an area three times the size of Central Park. In 2003, landscape architect James Corner Field Operations won an open competition to turn it into a 2,200 acre (890 ha) park.

The masterplan was “elemental, wild, romantic”, says Tatiana Choulika, principal at James Corner Field Operations. “The site is overwhelming – you have city views and ocean views, you have huge marshes and hills. The strength of our proposal was to embrace that big landscape feeling, not to try to make it look like a town garden.” After all, Freshkills is the largest green space in the city of New York – it’s just that nobody knew about it.

Choulika was also captivated by the mounds of trash themselves. “In the city, there’s no space outdoors where you can see everything without being in a building. From the top [of the mounds], there is this breathtaking view of the city. We decided to work with that.”

Soaking it up

The plan for Freshkills isn’t to return the site to its original landscape but to restore ecological processes, hoping that life finds a way back.

It has taken almost 20 years for the land rights, which were owned and maintained by the Department of Sanitation, to be transferred to the New York City Department of Parks & Recreation. But that still left one group that needed convincing of the project’s merits: Staten Island’s residents. The community might have been living with the stink of garbage for half a century, but even with the smell gone, they were still angry at the city: “When the park was announced people felt like the city was dictating their fate again,” says Choulika. We had to get out there and convince them that it was also for them.”

Although the first phases of the park are due to open in 2019, it will be another 20 years for the whole site to be “finished”, because some of the methods used to cap the older mounds no longer meet current regulations. As a result, the site is being opened up in stages as each mound is signed-off as safe.

Communities cannot always be persuaded. London’s Garden Bridge floundered and eventually failed in large part due to public outcry at the £60m in taxpayers’ money that was committed to what ultimately would have been only a quasi-public space. Whereas Seoul’s Skygarden connected up a fragmented part of the city, the Garden Bridge, as critic Rowan Moore described it in the Guardian, “would have been a cherry on the already rich cake that is the centre of London”.

James Harris, policy and networks manager of the UK Royal Town Planning Institute, says if you’re thinking about the most efficient way to spend a lot of money on green infrastructure, you’ll get much bigger bang for your buck using it elsewhere. “There are areas of London crying out for investment in good green infrastructure.”

Winning on aggregate

Councils are open to ideas. In 2017, the London Borough of Hounslow won the Mayor’s Award for Innovation in Planning for Rectory Farm, a scheme that will create a 110 acre (45 ha) public park out of a disused patch of greenbelt land. The site, which was farmed until 1996 before falling into disrepair, sits on top of a valuable supply of gravel. Landlord Formal Investments worked in partnership with the council over a 10-year period to come up with a radical concept.

“You could think of it as the largest roof garden in the world,” says Des Mahood MRICS, director at Gleeds, project manager for Rectory Farm. He explains that the gravel – enough to meet Hounslow’s share of minerals required by the London Plan – will be excavated from under the site creating a 2m ft2 (185,800 m2) underground warehouse. This will then be let to logistics companies attracted by the site’s proximity to the M4 and Heathrow Airport, while the public park above is maintained by the rental income from the occupiers below.

Mahood explains that with the project running over a 15-year period of extraction, construction and landscaping, the park will be opened in phases so that the local community can start to enjoy the benefits. “As greenbelt land, this could have been a contentious site, but the team were able to show that in its current form it was a missed asset, it wasn’t accessible to the community.” Bearing Mahood out are the results of a 2016 public consultation, which revealed that 95.7% of the 664 people surveyed approved of the proposals for the project.

At the heart of our cities is a conundrum: they grow if they can create jobs and the vibrancy that comes from a dense melting pot of cultures, but they must offset this against the green spaces, transit and amenities that much of their residents value. Being able to achieve this balance in the 21st century requires us to see the potential of every bit of land, and how it can contribute to something bigger.