What Are ‘Monkey Cheeks’ and Can They Solve Flooding in Bangkok?

Bangkok had a record-breaking rainfall in July 2022 that caused many districts to experience extreme flooding. People were stranded, classes were suspended, and boat services were halted. The police had to control traffic congestion, and officials dispatched several agencies to assist those who were affected.

While that’s over (for now), we can’t be so sure when such heavy rainfall will happen again as experts warned that Bangkok is at risk of more flooding if no improvements were made to its drainage systems. There’s also the issue of climate change, which contributes to heavier rains not just in Thailand but around the world.

Why Floods are Happening More

Poor urban planning and improperly thrown trash are only among the many factors causing floods, but one thing we should focus on is climate change.

Climate change per se isn’t the one directly causing floods, but it plays a huge factor on variables that cause flooding. For example, climate change has caused the world’s glaciers to melt at an alarming rate. This has contributed to rising sea levels, which amplify storm surges and increase the risks of high-tide flood. Climate change has also made our atmosphere warmer than usual. This causes seawater to evaporate more, contributing to heavier precipitation. While heavy rainfall doesn’t always lead to flooding, it still raises the potential in areas with poor drainage systems.

Addressing Floods in Bangkok

There are different types of floods, such as fluvial and pluvial, and one of them specifically occurs not due to an overflowing body of water but because there’s too much rainfall that it overwhelms a densely populated area’s canals and sewers. It’s called urban flooding, and it’s what has been happening in Bangkok. So, what’s the government’s solution? Floodwater retention basins.

Retention basins are pond-like structures that permanently hold water and are on standby to hold more water, like runoffs during heavy rainfall, to prevent flooding. Simply put, imagine having an almost empty pool that only fills up when there’s heavy rain and flood.

These basins are usually made in naturally depressed locations and in areas where flooding is common, such as industrial areas and shopping centres. They’re also interconnected to canals, streams, stormwater drains, and other systems located in roads and sidewalks to allow rainwater to reach the basins. In Thailand, they call these basins as monkey cheeks.

Monkey cheeks, or Kaem Ling (แก้มลิง) in Thai, is a term coined by King Bhumibol Adulyadej (also known as Phumiphon Adunlayadet or King Rama IX) to promote flood control measures in Bangkok. He noticed that when monkeys eat, they store excess food in their cheeks so they can chew and eat them later. In the same way, King Bhumibol thought that a retention basin can be an effective means to store rainwater instead of letting it flood the streets. The stored rainwater can likewise be used later after going through filtration during the dry season or simply released when seawater levels drop.

A Monkey Cheek That Also Serves as a Park

Chulalongkorn University’s Centennial Park is probably the best example if you’re looking for a monkey cheek in Bangkok. This 11-acre land in the middle of a concrete jungle can contain up to one million gallons of water and save the streets from extreme flooding. It’s inclined to create a container where the raised green roof, which is the largest in Thailand, directs runoff water through sloped rain gardens. It’s then filtered in the constructed wetland’s filtration system and directed to a retention pond. Meanwhile, the park’s mid-lawn serves as a detention area where the retention pond can overflow.

Apart from serving its purpose, the park is an open area where people of all ages can visit. It has an amphitheatre, an herb garden, a meditation walk, and a reading area adjacent to the pond.

You can read more about this amazing park through an interview with TED Fellow and Thai landscape architect Kotchakorn Voraakhom.