How 3 ASEAN Capitals Deal with Urban Flooding

How 3 ASEAN Capitals Deal with Urban Flooding

How 3 ASEAN Capitals Deal with Urban Flooding

It’s hot in the summer, and the rainy season brings lots of thunderstorms. When rainfall overwhelms the ability of drainage systems, flood control is the only resort many cities have developed in a bid to prevent more flooding in the future. Living ASEAN looks into how three regional capitals — Kuala Lumpur, Jakarta, and Bangkok — deal with urban flooding.

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Kuala Lumpur is one of rainiest cities in Southeast Asia with average annual rainfall as high as 2,393.6 mm. Situated at the confluence of two rivers, the city came into being as an important center of mining and trade in bygone times. Over time it attracted native Malays, Chinese workers, and immigrants from the Indian subcontinent. As the city grows, many planning updates have taken place especially along the waterfront. The initiatives include the “River of Life” project, which is aimed at reviving and restoring health and vitality to the Gombak and the Klang rivers.

Photo: Sitthhisak Namkham
Photo: Sitthhisak Namkham

In redeveloping the landscape, the authorities cleaned up the polluted rivers and got rid of unsightly concrete walkways along the riverfront. They opened up areas at the water’s edge by putting in shops, restaurants, and recreational spaces. Easily accessible to the public, the redesigned river corridor has drawn many people to the water.

One of Kuala Lumpur’s most ambitious projects is the Stormwater Management and Road Tunnel, or SMART. The mega project doubles as a storm drainage and road tunnel that helps reduce peak hour traffic. It’s also the longest storm drain tunnel in Southeast Asia. On dry days it functions as a normal motorway carrying traffic in and out of the city’s CBD. On days of heavy rains when rivers rise, the tunnel is closed to through traffic and functions as a storm drain system. The 9.7-kilometer-long tunnel works like a subterranean conduit carrying water to outlying natural r systems, thereby saving built environments in the CBD and around Jamek Mosque from being inundated. Nonetheless, flashfloods do occur occasionally. Oftentimes garbage-choked storm sewers are to blame.


Big floods in Jakarta, Indonesia. Project: JEDI. / Photo: Farhana Asnap / World Bank

Jakarta comes second with average 1,821-mm annual rainfall. It too faces the threat of flash floods as storm drains and waterways are choked with waste. Over time, shallow riverbeds, plastic garbage, and rampant encroachments combined to restrict the flow of stormwater out of urban areas. The authorities responded with a campaign to clean up all 13 waterways making them safe for riverside residents to swim. And the labor force to achieve that objective was readily available. Residents on the waterfront were hired to collect waterborne waste, thereby creating plenty of employment opportunities and increasing environmental awareness. The initiative cost 3.1 million Rupiah per month and provided jobs for more than 4,000 people daily. And it is showing good results. Take for example the Krukut River, which recently was blackened by pollution and solid waste, from old mattresses to discarded furniture. Nowadays more people are seen returning to swim in it like old times.


A few hours after the rain at a car showroom on Ratchadapisek Road, Bangkok / Photo: Sukwan Attajarusit
Photo: Sukwan Attajarusit

With average 1,466-mm annual rainfall, Bangkok is on the brink of floods with every rain despite it having plenty of canals and drainage systems. It doesn’t take long after rain for urban roadways to be inundated with floodwaters. The government sector has implemented a massive drainage tunnel project, but that is of little avail in the practical affairs of life in the city. Geographically Bangkok sits on a flat plain that rises only slightly above the mean sea level. That said, flood control is the only resort the city has in preventing or reducing the detrimental effects of flash floods. Its drainage systems work by channeling stormwater into canals, which in turn empty into natural water bodies via the flood gates. As the city grows, more rains continue to overwhelm the capacity of drainage systems that are severely choked with debris. With every rain, it’s not unusual to find workers pick up waterborne waste in areas near the water gates. During dry season, time is spent cleaning up storm drains and deepening of canals at intervals to prepare for more rain.

Big Floods in Thailand, 2011 / Photo: Aphirux Suksa
Big Floods in Thailand, 2011 / Photo: Aphirux Suksai


On the big picture, the three ASEAN capitals are facing a similar problem. They sit on flood plains, and flooding usually occurs as an overflow of water from natural water bodies, such as rivers. Interestingly, the people of each country have made the best of circumstances. This is evident in the way residential architecture has evolved over time. Houses on stilts with steeply sloped roofing and extended overhangs are emblematic of the region rich in local wisdom. The homes raised on piles protect against flooding, while steep roofing drains rain water fast. Meantime, long overhangs protect the interior from the elements.

As the city grows, each capital has its own way of fighting urban flooding. The multipurpose, subterranean conduit seems to work well for KL, as does the clean-up campaign in Jakarta. The drainage system is an essential part of living in the city, and both the government and private sectors must cooperate in a bit to prevent or reduce flooding in the future.


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