Opinion: Finding heritage-based fixes for floods

Whenever floods ravage Thailand, we hear many calls to enlarge drainage channels, construct new riverside barriers and build more pumping stations. But despite years of heroic engineering work, floods keep wreaking havoc.

To be sure, managing water is not an easy task. Climate change makes weather unpredictable. Many different public agencies and officials are involved, so it becomes difficult to coordinate the work.

But should we place our faith solely in bigger, smarter forms of conventional infrastructure? Or could we consider another approach? Are there other responses that are more attuned to ecology and local conditions?

"Nature-based solutions" has been a buzzword in environmental and urban management circles in recent years. In essence, this means harnessing the power of nature to tackle problems such as disaster risk management.

Reviving mangroves along coastal areas can help reduce the impact of storm surges. Soil contaminated by industrial pollutants can be treated using plants, micro-organisms, natural materials, and wind or solar energy. Such eco-friendly methods are often more cost-effective and sustainable than ordinary techniques. Conventional solutions tend to be expensive, require high energy input, and sometimes have unintended consequences like generating other forms of pollution.

In a similar vein, "heritage-based solutions" can also help. Heritage includes both our natural and cultural assets. So heritage-based solutions rely on nature as well as cultural know-how. Historic buildings, settlements and landscapes were designed based on a deep understanding of pre-existing natural systems related to land, water and climate. Traditional water management systems relied on the slope of the land, gravity, and the seasonal ebb and flow of water to function, with the aid of basic mechanics. This is in sharp contrast to a contemporary engineering mentality, which goes to great lengths to overcome the forces of nature, often in ways that are ultimately unsustainable.

Following the catastrophic floods that engulfed the Ayutthaya World Heritage site for over a month in 2011, Unesco supported the Thai government's Hydro Informatics Institute and Fine Arts Department to work alongside hydrological experts from the Netherlands to find solutions. One of their recommendations was to revive the ancient network of ponds and canals in the historic capital to increase the city's capacity to temporarily store water in times of acute flooding.

Urban planners pointed out the need to maximise the green area surrounding the city. These green spaces historically served as Ayutthaya's flood plain, but are today home to industrial estates paved in concrete. By understanding and enhancing the character of the "historic urban landscape", planners could get better results from new infrastructure projects, such as Bang Ban-Bang Sai Drainage Canal Project, which is now underway.

In other cities around the world, a combination of heritage-based solutions and technological innovation is gaining a stronger foothold. In Venice, also a World Heritage property, scientists have calculated that reviving the ancient system of cisterns for collecting rainwater (which numbered over 6,000 in the 19th century) could effectively fulfil modern water demands.

Following Superstorm Sandy in 2012, the New York City metro region has been rebuilding using so-called "blue-green infrastructure", ie a network of waterways and green spaces. Hard infrastructure, such as floodwalls, is being combined with soft landscaping, such as dunes along the coast. Ponds with aquatic plants and green roofs help to store, slow down and treat stormwater run-off.

Across Europe, the concept of "room for the river" requires creating open space along rivers to accommodate their natural swelling during rain events. Doing so has proven more effective than trying to build more dykes, channelise rivers or protect vulnerable buildings along the river that end up getting flooded anyway.

Here in Thailand, the application of heritage systems and indigenous and local knowledge is slowly gaining recognition. At Mrigdayavan Palace in Cha-am, coastal erosion is being managed by removing concrete embankments and other structures introduced after tropical storm Linda in 1997, which actually exacerbated erosion along the entire beachfront. The beach ecosystem is also being restored by removing alien species that were introduced over the years, such as pine and mangrove. Native beach plants have since naturally returned, attracting local birds and other species as well. Mrigdayavan Palace garnered a Special Recognition for Sustainable Development in the Unesco AsiaPacific Heritage Awards for Cultural Heritage Conservation in 2021 for integrating new architecture harmoniously into the natural and historic context.

Similar efforts to "go with the flow" can be seen elsewhere too. The Chulalongkorn University Centenary Park, for instance, embraces the nature of Bangkok as an urban wetland. Its design co-opts rather than fights flooding by capturing rainwater through an extensive system of water retention and treatment.

While flooding is the pressing issue of the moment, heritage-based solutions can meet other challenges. Traditional Thai methods of architectural construction rely on natural ventilation and renewable materials. They could help address Thailand's low carbon and climate change adaptation commitments by reducing energy use and waste. Other local knowledge and living heritage can also improve health care, food security and biodiversity conservation, as we've seen with the Moken people in the Andaman Sea or the Karen people in forest areas.

Heritage is still mostly considered a niche agenda in Thailand. But in fact, the 20-Year National Strategy and the 13th National Economic and Social Development Plan both flag the importance of enhancing local heritage across the country, not only for the sake of conservation but also for the sake of sustainable development.

As the fallout from the pandemic shows, the generative potential of heritage can no longer be limited to just the tourism sector, which is still struggling to revive and in some areas may never recover. Incorporating heritage-based solutions into a variety of sectors could help Thailand achieve a more sustainable future in line with its Bio-Circular-Green (BCG) vision and the global Sustainable Development Goals (SDGs).

This piece was originally published on the Bangkok Post.

Montira Horayangura Unakul works on the safeguarding and sustainable development of cultural heritage at Unesco Bangkok. Heritage Matters is a monthly column presented by The Siam Society Under Royal Patronage to promote public awareness and discussion on sustaining the architectural 4/4 and cultural heritage of Thailand and the region. Each column is written by a different contributor and appears on the third Thursday of the month. The views expressed here are those of the author.