Restrictions on movement, constrictions on space, destruction from flooding and the pollution caused by transport are increasingly affecting city life. In Bangkok, an innovative solution is addressing all these issues in an ambitious sustainable farm at Thammasat University Rooftop Farm. By Jared Green and Jeremy Torr.

Bangkok, November 2020. Designed by Landprocess, led by TED speaker and landscape architect Kotchakorn Voraakhom, the 1.7-acre Thammasat University Rooftop Farm (TURF) is a model of sustainable urban multi-use infrastructure.

Described as exactly what an urbanising world needs in the face of climate change, flooding, pollution, and a lack of access to high-quality fresh produce, TURF brings an integrated design approach to the biggest urban farming roof in Asia where architects, landscapers and engineers have crossed disciplinary boundaries to create better projects for both people and the environment.

According to Voraakhom, the initial design for the new campus building was just a building. But she convinced the architecture and engineering teams to collaborate with her on the concept. She suggested that given a large park was being developed in front of the building, why not just continue up over the building and link the rooftop green space with the park on the ground?

“In the end, the design team and the clients all agreed this option will have a bigger impact,” she said. “Bangkok is a city of water but we don't know how to drain our water. We've been through many floods: this happens because we don't know where the water should go.”

Inspired by traditional terraced farming found in mountainous regions across Southeast Asia, the rooftop farm uses an intricate, slightly inclined structure and gravity to cascade rainwater down each level. As rainwater zigzags down the slopes, each level harvests runoff from the previous cell, forming unique clusters of micro-watersheds along the terrace to help absorb, filter, and purify rainwater while growing food for the campus. This approach slows down water 20 times more effectively than a conventional roof, avoiding water erosion. Any run-off is then captured in four retention ponds pools at the base of the building that can store more than three million gallons of water.

“We try to fix problems, but we are actually the problem,” says Voraakhom. “We don't let the land absorb rain. We have to see the problem systematically and fix what we have done rather than try to fix nature.”

The $31 million project shows what is possible through an integrated design approach. To address the problem of the lack locally produced healthy organic foods, the team created a productive landscape which produces nearly 50 kinds of edible plants, including rice, indigenous vegetables and herbs, and fruit trees. And it looks good too - there is Jamaican Cherry, White Cheesewood, Camphor, Red Sandalwood, and Ceylon Oak trees, intermixed with lemongrass, basil, amaranth, rice, and okra. Rows of dill, Thai eggplant, red and green oak-leaf lettuce, green roselle and Thailand’s favourite - bird’s-eye chili peppers all nod in the breeze. This profusion provides some 20tonnes of organic food annually, enough for 80,000 meals in the campus canteen. Food scraps from the canteen are composted and returned to the roof farm, creating a sustainable food cycle.

The 40,000 campus residents and surrounding community are encouraged to work on the farm and re-learn how to plant and harvest, reconnecting with their agricultural history; a century ago, King Rama V created the Rangsit rice plantations and canal system on the site of the rooftop farm. His goal was to make Thailand a major rice producer, but as the city expanded the rice fields were paved over. Now, students and residents learn about this cultural landscape and heritage, with the farm offering access to workshops on agriculture, nutrition, and permaculture.

The Thammasat site also helps reduce dependence on fossil fuel use through the installation of solar panels that generate 500,000 watts of electricity per hour. Voraakhom explains that this extra power runs pumps that pull water from the retaining ponds to irrigate rooftop crops in the dry season.

The farm also calls on smart passive strategies that reduce energy use overall. The green roof insulates the building below, reducing its cooling energy needs. And air that passes over the retaining ponds gets cooled by the collected water before it reaches the building, creating natural air conditioning. Even the layout of the building itself makes a nod towards sustainability.

“With its division into four equally-accessible sections, each chamber represents a core element of democracy—people, liberty, equality, and fraternity,” say the designers. It is a virtuous cycle, made real.

“Green roofs are one of the key solutions to make a city more porous and sustainable,” says Voraakhom. “When it comes to healing, no one can help you. Doctors can cure you, but they cannot heal you. You have to heal yourself. And how do you heal yourself? You heal yourself through natural processes.”

The original story on TURF was published in The Dirt. https://dirt.asla.org/