This green roof and farm offer a Swiss army knife of solutions — flood control, solar energy, fresh produce, green space for city dwellers, jobs, learning opportunities, and more — to some of our most pressing urban problems. Landscape architect Kotchakorn Voraakhom tells us how it works.
Could cities actually be designed to improve the environment? Bangkok, Thailand, landscape architect Kotchakorn Voraakhom, a TED Fellow, thinks so. Her imaginative work challenges the prevailing thinking that urbanization has to have a negative impact on the planet, whether it’s in the form of flooding due to paved surfaces, excessive energy use, disrupted biodiversity or the heat island effect.
With her firm Landprocess, Voraakhom has designed a new green roof on the Rangsit campus of Thammasat University, about 25 miles north of central Bangkok. Bangkok is extremely vulnerable to catastrophic flooding — in fact, according to the World Bank, nearly 40 percent of the city, which is built on a river delta, may flood annually by 2030, and this situation has been greatly exacerbated by paved-over earth and intensifying rainy seasons.
The Rangsit green roof is the follow-up to Voraakhom’s award-winning Chulalongkorn University Centennial Park, an 11-acre green space in downtown Bangkok that can capture and hold one million gallons of water in its retention pond and storage tanks and prevent it from submerging the city. (Watch her TED Talk: How to transform sinking cities into landscapes that fight floods.)
As if that weren’t impressive enough, Voraakhom’s new 236,806-square-foot structure — which opened in December 2019 — encompasses a flood-water management system and also Asia’s largest rooftop organic farm. “We’ve combined the principles of modern landscape architecture with traditional agricultural knowledge to create a Swiss army knife of environmental solutions, integrating water management, green energy, green public space, and more,” says Voraakhom. “Meanwhile, by 2050, 80 percent of the world’s population will live in cities, and water will be a scarce commodity. We need to start using city spaces more efficiently to ensure a secure and sustainable source of food production.”
The green roof, containing an H-shaped lush landscape, looks like a futuristic hill with a brick building nestled snugly beneath it. “The hill features an intricate pattern of zigzagging terraces of planted beds, leading all the way down to the bottom,” says Voraakhom. “When rainwater hits the roof, it cascades down the zigzags cut into its slopes while being absorbed by the soil in the beds.” The excess water is channeled into four retention ponds – with a capacity of up to 3 million gallons at the bottom of the mound. “The process slows down the flow speed of rainwater runoff by 20 percent compared to a normal concrete rooftop. This keeps a large amount of water out of the sewage systems, preventing the area from flooding during heavy rains,” she explains. The shape of the building also pays respect to one of the founders of the campus, economist Puey Ungphakorn. “‘Puey’ means ‘mound under the tree’ or ‘nourishment’ in Thai,” she adds.