2011 Thailand Floods: Bangkok and the Global Supply Chain

The 2011 Thailand floods were the worst flooding in the country in more than half a century. From late July 2011 to January 2012, water spread slowly down the Chao Phraya river basin, inundating farms, towns, the old capital of Ayutthaya and the northern suburbs of Bangkok. The floods killed over 800 people and, by swamping seven major industrial estates, disrupted the production of cars and computer hard drives around the world.

Causes: a wet year in a crowded basin

The Chao Phraya is Thailand’s main river, flowing south through a broad, flat plain from the northern hills to the Gulf of Thailand past Bangkok. The basin floods naturally in most years, and Thai rice farming long depended on it. Since the 1980s, however, the plain had filled with towns, roads and industrial estates built on former paddy fields and floodways.

The 2011 monsoon was exceptionally wet, with rainfall in northern Thailand far above average. Tropical Storm Nock-ten in late July and several later storms added heavy rain. The two largest reservoirs, behind the Bhumibol and Sirikit dams, kept water for the dry season and then, as they neared capacity in September and October, had to release large volumes. Experts and officials later disagreed over how much reservoir management contributed to the disaster. Many also blamed decades of unplanned development that had blocked natural drainage channels and paved over land that once absorbed floodwater, as well as land subsidence around Bangkok caused by pumping groundwater.

The flood spreads south

Flooding began in the north in August and moved slowly south through provinces such as Nakhon Sawan and Lopburi. Because the land is so flat, the water advanced over weeks rather than hours, and areas remained under water for one to two months.

In October the flood reached Ayutthaya, the historic capital founded in 1351 (see founding of Ayutthaya). Temple ruins in the UNESCO World Heritage park were inundated. Most damaging for the economy, floodwaters broke through barriers around seven industrial estates in Ayutthaya and Pathum Thani provinces between early and late October, including Saha Rattana Nakorn, Rojana, Hi-Tech, Bang Pa-in, Factory Land, Nava Nakorn and Bangkadi. More than 800 factories, many owned by Japanese companies, were submerged under up to 2-3 metres of water.

Bangkok under threat

The government of Yingluck Shinawatra, who had become prime minister only in August 2011, set up a Flood Relief Operations Command at Don Mueang Airport, Bangkok’s older airport. The airport itself flooded on 25 October and the command had to move.

Authorities tried to protect inner Bangkok, the city founded in 1782 (see founding of Bangkok), with flood walls, giant sandbag barriers known as “big bags” and pumping through the canal network. Northern and western districts such as Don Mueang, Lak Si, Sai Mai and Bang Phlat were flooded, while the business centre stayed mostly dry. Residents outside the barriers sometimes tore down sandbag walls, accusing officials of sacrificing their neighbourhoods to save the centre.

The water slowly drained to the sea, and most areas were dry by mid-January 2012.

Impact on the global supply chain

The floods showed how much modern manufacturing depended on a few locations. Thailand was the world’s second-largest maker of hard disk drives, and plants of Western Digital and many component suppliers stopped production. Global hard drive shipments fell by around a quarter to a third in the last quarter of 2011, and prices rose sharply, in some cases roughly doubling.

Car makers were also hit. Honda’s factory in Ayutthaya was flooded, and Toyota, Nissan and other manufacturers cut output in Thailand and abroad because of parts shortages. Coming only months after the Tohoku earthquake and tsunami had disrupted factories in Japan, the floods pushed many companies to spread production across more sites and keep larger stocks.

Casualties and cost

Thai authorities reported 815 deaths, many from drowning and electrocution. Around 13 million people were affected in 65 of the then 77 provinces, and some 20,000 square kilometres of farmland was damaged. The World Bank estimated damage and losses at about 1.43 trillion baht (around 46.5 billion US dollars), and Thailand’s economic growth for 2011 fell to under 1 percent.

Timeline

• 2011, late July: Tropical Storm Nock-ten brings heavy rain to northern Thailand.
• 2011, August-September: Floods spread through northern and central provinces.
• 2011, October: Seven industrial estates in Ayutthaya and Pathum Thani are flooded.
• 2011, 25 October: Don Mueang Airport floods.
• 2011, November: Northern and western Bangkok districts are under water.
• 2012, mid-January: Floodwaters recede from most affected areas.

Why it matters

The 2011 Thailand floods were among the costliest disasters of their time and a turning point in understanding how a regional flood can ripple through global supply chains. They prompted Thailand to plan new flood defences and water management, and led manufacturers worldwide to rethink where and how they concentrate production.