Today, as our constantly-fluctuating climate causes rising sea levels, storm surges, and unexpectedly heavy rainfall, low-lying cities across the globe are bracing for urban flooding disaster. As sea levels rise and concrete infrastructure multiplies, Bangkok is sinking two centimeters every year.
For the first time in 30 years of rapid urban development, an invaluable property at the heart of Bangkok—11 acres of land and 1.3 kilometers of the road— was not turned into another block for commercial use. Instead, it is transformed into a public park for people. Opened in 2017, Chulalongkorn Centenary Park is the first critical piece of green infrastructure in Bangkok to mitigate detrimental ecological issues and reduce disaster risk.
Unlike other public parks around the city, this is the first in Thailand to demonstrate how a park can help the city reduces urban flooding and confronts climate change, all while offering city dwellers a place to reconnect with nature. Designed with innovative ecological design components, the park reminds the city how to live with water, rather than fear it.
Bangkok is a flat city. By harnessing the power of gravity, The park is able to sustainably collect, treat, and hold water to reduce urban flood risks in its surrounding areas. Sitting on a three-degree angle, the park is equipped with several ecological features, from its highest point,—green roof, wetlands, detention lawns, to its lowest point, retention pond—leaving not a single drop of rain wasted. The rain and runoff are pulled down through the park’s topography to generate a complete water circulation system. Taking into account a 50-year period of rainfall intensity and the frequently overwhelmed public sewage system, the park is able to hold up to a million gallons of water during heavy rainfall.
At the park’s highest point, any member of the public can see Bangkok’s skyline—not on an expensive rooftop bar or a skyscraper helipad, but atop the biggest green roof in Thailand covering 5,200 square meters where open skies and green grass are free to all. Laid with low-maintenance native grass and weeds which attract local birds and insects, the roof provides a unique experience of a rural and natural environment with a dense urban backdrop.
Excessive runoff from the green roof then flows down to four constructed wetlands, two on each side of the park. A series of cascading weirs and ponds slow the runoff and increase water aeration, aided by native water plants that filter and clean the water. In the concrete city of Bangkok, the park provides a hidden oasis where kids and adults can explore and interact with wetlands and hear the sound of flowing water.
The main lawn at the park’s center is a vast inclined open space for recreational activities. Unlike other flat parks around the city, this inclined park offers the unique experience of multi-purpose amphitheater for public events. On stormy days, the lawn absorbs rain and runoff, using gravity to send the water to the retention pond by the low end of the park. During severe flooding, this retention pond can store excessive water and double in size by expanding into the park’s main lawn. Visitors, too, can become an active part of the park’s water treatment system by hopping onto any stationary water bikes along the pond and using their exercise to keep the water aerated.
Featuring sustainable drainage systems, a green roof, wetlands, porous areas, ponds, an open swale, small pocket parks, detention lawns, and a retention pond, the park is a premiere example of various landscape solutions for urban flood disaster reduction. Bangkok desperately needs more parks, but more importantly, productive ones that can sustainably confront climate uncertainty.
As Bangkok experiences droughts and monsoons, the park’s water and landscape will continually grow and transform to unveil new environments for visitors to experience. Following the planting concept of establishing urban forests, 258 varieties of plants and trees have been grown either from seed or as young seedlings which easily adapt to climate changes, recreate a healthy ecosystem, and provide habitat for local birds, pollinators, and insects.
Underneath the green roof lies a museum and parking space, made possible by the inclined architecture. Additionally, three underground tanks store rainwater absorbed from the green roof. The amount of water held can irrigate the park for up to a month during dry seasons.
While playing a role in confronting climate risk, the park simultaneously serves as a recreational space and outdoor classroom for the university community, surrounding neighborhoods and urban dwellers. Adjacent to the main lawn are eight “landscape outdoor classrooms,” each with different biomes and layouts, lining both sides of the park to serve as diverse multi-purpose areas. They include an herb garden, meditation area, reading room, bamboo garden, playgrounds, and earthen amphitheater. Whether in the choice of porous components or locally-sourced materials, these outdoor classrooms incorporate details to best complement the park’s main ecological features.
The first of its kind in Bangkok, the 1.3-kilometer road running perpendicular to the park was redesigned to shift priority from cars to pedestrians and cyclists. By reducing four vehicle lanes into two, providing space for people walking and biking, the once heavily-congested street now seamlessly connects pedestrians and cyclists directly to surrounding neighborhoods’ residential, entertainment, and retail facilities. The park is lined with corridors of rain gardens on both sides to provide shade and human comfort, and reduce runoff from the adjacent road surface. This design is evidence to Bangkok the possibility of a commercially-developed area that is, finally, pedestrian-friendly.
While climate change has been a prominent issue for decades, we are undoubtedly moving towards an age of sustainability and resiliency. A single park cannot control flooding across an entire city, but Chulalongkorn Centenary Park is a big, bold first step. Urban development is inevitable and the population is bound to rise, but it is our obligation as landscape architects to consider every possible solution and sign of hope for our future.
Landscape Architect: LANDPROCESS
Architectural Design: N7A architects
Structural Engineering: (CASE) Civil AndStructural Engineers
MEP Engineering: EEC Engineering Network
Main Contractor: Syntec Construction
Construction Manager: CONSULTING & MANAGEMENT 49 (CM49)
Softscape Contractor: CORDIA
Graphic Designer: G49
Location: Chulalongkorn University, Bangkok, Thailand
Size Area: Park 44,800 sq.m. (28 Rails) Road 1.57 km ( 29.4 Rails)
Scope: Master Planning, Landscape Design
Project Status: Completed March 2017