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Asia’s largest urban rooftop farm

by Ofentse Sefolo
Asia’s largest urban rooftop farm

The cities in Southeast Asia, and Bangkok in particular, are among the most vulnerable to climate impacts in the world. They are victims of their own rapid development and unchecked industrialisation, coupled with unpredictable extremely wet and dry weather. It has become the new normal, causing flooding, damaging agriculture, destroying livelihoods and threatening millions of people.

But it seems that there may be an industrious solution just a short trip away. The introduction of a new integrative solution at Thammasat University (TU) has emerged to create climate resiliency, demonstrating how development can contribute more solutions than the problems it has created by embracing landscape architecture and past agricultural practices.

Asia’s largest urban rooftop farm

As the largest urban rooftop farm in Asia, the 22 000m² (236 806 sq. ft.) Thammasat University Green Roof tackles climate impacts by incorporating modern landscape architecture with traditional agricultural ingenuity, the green roof, urban farming, solar roof and green public space.

The project combines the elements of architecture and landscape architecture so seamlessly that it is almost impossible to categorise what type of work it is. The form of the building is developed from the H-shaped floorplan, rendering the elevation that resembles a large mountain with a massive green space of garden covering the upper part.

By mimicking traditional rice terraces, Thammasat University Urban Farming Green Roof has become an all-in-one solution – as a public green space, urban organic food source, water management system, energy house and outdoor classroom – which serves as an adaptation model for anticipated climate impacts that can be implemented and developed across Thailand and Southeast Asia.

Architecture creates a solution to climate, food and pollution crisis
The Rangsit field of per-urban Bangkok was once filled with paddy fields and swamps, envisioned by King Rama the 5th to be the most productive rice-farming area in the world. But after years of unstoppable urban sprawl, the marshlands have turned into paralysed concrete cities, no longer able to breathe, absorb water or grow food.

To revive the land which it stands on, Thammasat University, one of Thailand’s leading universities, has created innovative architecture by transforming an unused rooftop into a solution to the climate, food and pollution crisis.

Inspired by local ingenuity and traditional agricultural practices, the Thammasat University Urban Farming Green Roof’s cascading farm levels form a detention lawn which slows down, absorbs and stores rainwater while using it to grow food. Any runoff is filtered through each layer of soil and later saved up in four retention ponds, which can collect the water up to 11 718 cubic metres (3 095 570 gallon) for rooftop irrigation and future use to restore biodiversity back into the swamplands.

The native plant strains grown on the farm create a microclimate and attract pollinator bird and insect species. As the plants on the Thammasat University Green Roof breathe, the oxygen and moisture they release help to build a stable microclimate for the animals to take refuge.

Cascading rice field farming methods elevated by modern landscape architecture

Although concrete absorbs and reflects most heat, it barely absorbs any water, leaving cities like Bangkok at risk of urban flooding whenever it rains. By incorporating the resourcefulness of farmers on mountainous terrains across Southeast Asia with modern landscape architecture, the Thammasat University Green Roof mimics the form and functions of traditional rice terraces to achieve maximum productivity, collecting and storing rainwater efficiently for times in need.

During heavy rainfalls, abundant soil mass and nutrients can be lost along with the runoff. But with cascading layers of planters, the plants on the Thammasat University Green Roof hold the soil together and slow down runoff. By embracing not only the intention of organic, but also regenerative agriculture, it ensures a food source beneficial to both the health of humans and nature.

With each cascading level, the green roof is not only able to absorb rainwater, but to also slow down runoff, both for up to 20 times more than a normal concrete rooftop. While controlling the stormwater peak rate and volume, this water management system also retains and utilises runoff efficiently to grow food for the campus.

Equipped with four retention ponds at each of its corners, it also significantly reduces the volume of stormwater leaving the site, saving the water for future use and irrigation during dry spells.

As intensive agriculture expands, monoculture crops continue to scour natural food sources and leave trails of deadly chemical fertilisers and toxic waste behind. Thailand is among the world’s top five countries importing pesticides.

By cutting chemical pesticide and fertiliser use altogether, the Thammasat University Green Roof offers organic farming as a model for sustainable landscape management to transition from chemical-dependent agriculture for both the sustainable health of people and the environment, as well as the economy.

In addition to preventing runoff pollution from entering drainage systems and later rivers, lakes, and oceans, the Green Roof’s vegetable terraces also filter the rainwater – often carrying air pollutants into water bodies – through several layers of plants and soil before it leaves the site and reaches residential water sources and marine ecosystems. The plants also help to remove harmful pollutants from the atmosphere.

Green stats:
Green Roof area: 22 000m² (236 806 sq. ft).
Urban farming area: 7 000m² (75 300 sq. ft), 32%.
Solar roof area: 3 565m² (38 373 sq. ft.), 16%.
Public space area: 7 000m² (75 300 sq. ft.), 32%.
Service and utility: 4 435m² (47 738 sq. ft.), 20%.
Building area: 60 000m² (645 840 sq. ft.).

Building climate-resilient cities from solar power

Now filled with numerous skyscrapers and many wasted concrete rooftops, Bangkok can only reach up to 40˚C, as concrete soaks up most sunlight and reflects heat to its surroundings. Instead of another wasted rooftop which contributes to urban heat islands, the mountain-shaped Thammasat University Green Roof utilises its vast space as an infinite source of clean energy – not only in terms of organic food, but also solar power for the community.

Taking advantage of the abundance of sun Thailand receives, the Thammasat University Green Roof harnesses readily-available solar energy at zero production cost and produces 500 000 watts (equivalent to 25 000 electric lights) per hour to pump water for irrigation on its urban farm, as well as generate electricity inside the building underneath it.

Placed on the south side of the architecture, the solar panels of the Thammasat University Green roof – covering the total 3 565m² roof – are exposed to sunlight all day long.

By incorporating this renewable photovoltaic system, the Thammasat University Green Roof not only cools air both inside and outside of the building, reducing greenhouse gas emissions from and spending on energy consumption, primarily from air-conditioning. Similarly, it can also improve insulation to retain the cooling temperature.

Feeding 135 000 with the green canteen

It is estimated that 80% of the world’s population will live in cities by 2050. As we see prolonged periods of erratic weather patterns and extreme seasonal changes, food and water scarcity poses one of the biggest threats to human civilisation.

The traditional ingenuity used by rice farmers on the sloped hill and mountain terrains across Southeast Asia is incorporated into the Thammasat University’s Green Roof, means it can grow approximate 135 000 rice meals each year to feed the community.

While the urban rooftop farm holds the key to the Thammasat University Green Roof’s functions, the green canteen completes its intended purpose of creating a truly holistic and sustainable model for business and conservation. By building both the organic food source and destination in proximity, the system reduces emissions and waste – produced during production, processing, packaging, transportation, and disposal – from start to finish.

Growing a variety of indigenous plant species and a naturally bred strain of rice tolerant to floods and droughts, the Thammasat University Green Roof serves produce fresh from the farm roof to the table. Once the organic food is distributed to the local community, any food leftovers from the plate and the kitchen are composted and sent back to feed the farm as organic fertiliser to grow nutritious crops for the next harvest.

By creating a localised food supply chain that produces all-organic vegetables, the Thammasat University Green Roof’s urban farm and organic canteen are able to reduce both emissions and pollution from its production, consumption and disposal by cutting chemical use, energy consumption and food waste while encouraging a low-impact, plant-based diet.

Redefining Thailand’s agricultural sector

The Thammasat University Green Roof creates employment for students and staff inside and surrounding the campus, while giving them the opportunity to contribute to feeding the community and conserving the ecosystem through sustainable agricultural practices.

By establishing a functioning and self-sustaining farming model which puts human well-being and ecological health at core, the Thammasat University Green Roof is redefining the operations of Thailand’s agricultural sector.

It is making food production profitable again for small-scale farms and creating employment and businesses opportunities for grassroots farmers, as well as redistributing land and food sovereignty from monopolies and middlemen to create more income equality.

Similarly, by reshaping agricultural work, one of the Thammasat University Green Roof’s objectives is to diffuse economic power in urban Bangkok and other major cities and spread development evenly across the country’s geography.

Passing on land and knowledge to the next generation

Built at Thammasat University, a member of the Sustainable Universities Network, the Thammasat Green Roof serves as another landmark for the university’s commitment to bringing urgency to climate issues.

In order to equip visitors with the knowledge for real-world application – on how to grow food, especially to prepare for climate uncertainties with available resources – offers not only information about the green roof’s features but also year-round workshops on sustainable agriculture and urban farming for 40 000 members of the university campus to take home.

The Green Roof holds incredible potential in the replicability of its current blueprint, as well as possibilities for improvement and modification to suit other cities struggling with climate impacts across the world.

To wholly fulfil its role as part of an academic institution, the Thammasat University Green Roof is also committed to serve as an outdoor classroom for students, faculties, staff and visitors to understand more about climate resilience and climate justice. Annual activities based on the farming calendar provide inclusive learning about permaculture, nutrition and sustainable development.

With this integrative approach, the Thammasat Green Roof aims to educate the community about the impacts, causes and solutions of climate change – which is an umbrella to both the ecological and human rights lens of the food, energy and waste industry, as well as water management, financial economy and governance – to ground them with information to reflect on their personal carbon footprint and share their newfound knowledge with their social networks.

This holistic solution was inspired by the local ingenuity, carried on by several generations of farmers who learned from the land and water they lived with. To show our young leaders how to welcome the challenges of the uncertain future, past knowledge about the origins of their culture and native soil have been embedded in the Thammasat University Green Roof as lessons for them to adapt and actively take forward.

Thammasat University, Rangsit Campus:
• Location: Bangkok, Thailand.
• Building type: Multi-purpose building with the biggest urban farming green roof in Asia.
• Project owner: Thammasat University.
• Landscape designer and green roof design: LANDPROCESS (Kotchakorn Voraakhom).
• Architect: Arsom Silp Institute of the Arts.
• Structural engineer: Degree System Co. Ltd.
• System engineer: TPM Consultants Co. Ltd.
• Contractor: CM49.
• Images and diagrams: Courtesy of LANDPROCESS.

Acknowledgement and thanks are given to Thammasat University and LANDPROCESS for the information contained in this article.

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