Managing the Thai floods

Managing the Thai floods

A group of university students has come up with unique solutions to a recurrent problem

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HKU students visited Thailand and came up with solutions to ease the flooding problems.
HKU students visited Thailand and came up with solutions to ease the flooding problems.
Photos & illustrations: HKU
Three months of heavy rain in 2011 triggered the worst flooding in central Thailand in a half century, killing nearly 800 people and costing the country an estimated HK$350 billion.

Last year the Thai government decided to keep the area's main reservoirs - used for irrigating crops - half empty during the drier months in case of another great flood. The deluge didn't come, but farmers are now experiencing another crisis: drought.

Thailand's troubles have served as a valuable case study for student architects at the University of Hong Kong, who think Thailand's current water management strategy is flawed, after meeting Thai officials and visiting sites around the country last year. The team of nine students from the Department of Landscape Architecture will compile their research into a formal recommendation and send it to Thai officials.

One of the students, Jean Chan Mei-yee, proposed that rather than rely on centralised reservoirs, farmers build their own ponds next to their fields, as in her sketch below.

"As the annual monsoons are increasingly hard to predict, it's hard for dam managers to estimate how much water to release," Chan says. "This strategy would free up space in the dams to deal with another flood."

During the 2011 disaster, she notes, the largest dam in Thailand released 60 per cent of its water, flooding villages downstream.

In case of droughts, meanwhile, her system would allow farmers to rely on water from their own ponds, which could also be used to cultivate fish while mud scraped from the bottom could serve as fertiliser for crops.

Her classmate Wiley Ng came up with another solution: super-sized canals between rice paddies that could hold flood water, instead of directing all the excess water into a less economically valuable basin with multiple dams. He says this would ease the pressure on reservoirs, and when farmers experienced a dry season, the canals could be used for planting.

However, both plans would need the cooperation of farmers across the country, which could be a challenge.

Then there is the problem of tall flood walls built around industrial sites. They, too, contribute to flooding, says project member Tamsin Thornburrow. Many factories have been built like forts to protect their financial investments. When they start pumping rainwater out into surrounding areas, they make matters worse for nearby communities. Often industrial chemicals leach into the flood water, contaminating local water and food sources.

Some factories have two sets of walls circling them, one further from the buildings than the other, with a space in between. Thornburrow worked out a solution for one such factory. She recommends building a wetland in the gap, as in her sketch above, so that excess water can be trapped and treated there.

"For industrial estates to become more sustainable, water must be managed within the site by means of filtration and reuse," she says.

Assistant professor Dorothy Tang, who oversees the projects, hopes the students' solutions will help the Thai government rethink its strategies.

"[These solutions] would help add further value ... to the landscape, in addition to controlling floods," she says.

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