Singapore is heavily dependent on Malaysia for its water supply but is now creating new sustainable parks designed to reduce its reliance, said Herbert Dreiseitl, International ASLA, Atelier Dreiseitl, at the Greater & Greener: Reimagining Parks for 21st Century Cities, a conference in New York City. As an example, his amazing new 62-acre Bishan-Ang Mo Kio Park recreates nature, transforming a 2.7-kilometer concrete-channel lined river into a 3-kilometer natural meandering system. At the same time, the new system slows down and stores some of the rainfall that hits the city-state. The park is a model for how cities can transform outmoded, broken systems into natural systems.
Singapore has to import so much water because all its hard surfaces funnel water straight into the ocean. In the tropical heat, much is also lost to evaporation. “They can’t keep their water they have.” To address these problems, the city-state has created a new strategic master plan to reduce reliance on Malaysia and capture more of its own water for reuse. The new plan, which includes water guidelines Dreiseitl created for the Singaporean government, focuses on “collecting, slowing down, and storing rainwater.”
A central catchement — the Kallang River — is part of the larger system providing drinking water to the city-state. In the past, the river was actually set within a concrete channel in many key places so in heavy monsoons it would flood and then evaporate.
Dreiseitl convinced the government to let the river escape its concrete channel and meander through the park, turning an “old-fashioned park and canal” into green infrastructure system that teaches the community about how nature actually works. The new system is actually a lot safer — the previous concrete channel actually killed many residents who were playing soccer down there when flash flooding struck.
In Dreiseitl’s cutting-edge approach, the “blue and green are integrated.” To achieve this, he has to convince the city departments that handled water and parks to abandon their siloed approaches and better communicate with each other. “Now, territories, finances, and maintenance overlap.”
To make this seismic change happen, Dreiseitl said he had to get the Singaporean government to trust his new approach, so he actually used his own design fee to create a test site. Exploring 12 different “bioengineering techniques,” Dreiseitl commissioned a set of in-depth hydraulic and materials studies. He was floored by how “crazy” the plants grow in Singapore so he had to adjust his models based on plant growth. He figured out what kinds of soil conditions would ensure slope stability in those temperatures. Lastly, he invested heavily in training the construction workers. “We couldn’t just show them pretty drawings of the new systems because they had no experience with these systems. We had to train them.”
With the approval of the government in place, Dreiseitl moved towards creating a new stream while the river was still flowing. In a feat of sequenced engineering, Dreiseitl managed to re-engineer soils, add bio-engineered plant systems along with trees, break up the existing concrete channel and reuse the rubble to stabilize the entire system — all while the river was still running. No artificial fertilizers were added. All materials on site were reused. In fact, some of the excess rubble was used to create a new hill, a look-out point over the park.
Importantly, the new system actually works. Dreiseitl said the new river “can hold lots of capacity and cuts in half the peak floods.” The new, cleansing biotope digest pollutants and creates oxygen in millions of gallons of river water each day. Some of the cleansed river water is diverted and reused in the watery playscapes. Before the water touches people, it’s further cleansed by a UV radiation filter. “It’s not only a purification system, but also a beautiful garden.”
The German landscape architect said for the project to work Singaporean officials just needed to be “learn how to behave with risk.” They had wanted to put a fence around the meandering river to keep people out of the flood plain, but Dreiseitl threatened to quit over that, arguing that it would not only ruin the design but break the human connection to the natural system. Instead, Dreiseitl’s team worked with the government to create an “amazing” early warning system, with towers that flash lights and use loudspeakers to make announcements in 6 languages so people can still sit down there but get early warnings when the river is going to overflow.
He thinks this kind of experience with nature in Singapore, the “most artificial of cities,” is critical. In Singapore, everyone “lives in of air-conditioning. They use underground subways and go to underground shopping centers” to escape the heat. As a result, much of the population is cut-off from nature. He said kids are particularly blown away by the wildlife in Bishan. Since the park was redesigned, biodiversity is up 30 percent. There are now 59 species of birds, including sea eagles, and 23 kinds of dragonflies.
To add proof to a recent U.S. National Park Service report that being near a wildlife preserve raises property values, Dreiseitl said the nearby apartments are up 48 percent in value since the park opened. To laughter, he added, “I should have bought a place before it opened.”
Dreiseitl believes that to implement such a game-changing system landscape architects need to have a “strong, logical argument.” Designers “must convince with a narrative.” There has to be inter-disciplinary planning with engineers and architects to capture all the benefits. He also said climate change can be a “engine” for convincing clients to move forward with new models like these. “In the past, cities thought water was a problem to get rid of, but with climate change we need to focus on water security and reuse all water.”
Image credits: Atelier Dreiseitl