Houston's lessons relevant to Asia's coastal cities, say experts

People walk through the flooded waters of Telephone Road in Houston on Aug 27, 2017.
People walk through the flooded waters of Telephone Road in Houston on Aug 27, 2017. PHOTO: AFP

The Houston neighbourhood where Ms Chris Wolf was marooned in her house last weekend is called The Heights - and it is just 18m above sea level. The city is, on average, just 24m above sea level.

Houston is no stranger to floods. They occur almost every year, but not on this scale. This year's epic disaster has triggered a new round of discussion on how coastal cities can adapt to the new threat of increasingly frequent extreme weather events. The lessons are relevant to densely populated coastal cities in Asia, experts say.

As in Mumbai, Bangkok and half a dozen other coastal Asian cities, rapid growth of concrete urban infrastructure and conversion of wetlands that act as natural drainage have made Houston more vulnerable to flooding.

Also mirroring the explosive growth of coastal Asian cities, Houston has grown faster than most other cities in the US, and is today America's fourth-largest.

"We are adding about 100,000 people a year," Professor Sam Brody of Texas A&M University in Galveston told NBC News. "With those people come parking lots, pavement, rooftops, roadways - and that makes it very difficult for the water to drain."

Mr Greg Norman, a spokesman for Houston's Public Works Department, said in a phone interview with The Sunday Times: "That does have an impact on drainage, because it covers land that would normally be available to absorb storm water."

The same applies to Mumbai, which is suffering annual floods made worse by the constriction of natural drainage and conversion of natural green areas. "Mumbai cements open spaces, fills wetlands, hacks trees, chokes drains, over-constructs. Result? Traumatic flooding," said editor and environmental activist Bittu Sahgal.

TAKING MEASURES

There are two things cities can do: Build infrastructure that is resilient to climate and weather events, that might cost 5 or 10 per cent more - which is pretty small compared to the risk; and use green infrastructure like water bodies and spillways to manage weather events.

MR ANI DASGUPTA, Washington-based global director of the World Resources Institute's Ross Centre for Sustainable Cities, on mitigating the effects of flooding.

Mumbai suffered a devastating flood in 2005 that killed more than 1,000 people. Since then, if anything, the situation is worse, Mr Sahgal told The Sunday Times.

And like other overbuilt coastal cities - Bangkok, for instance, where in 2011 flood water stood for days without draining - Houston has also been sinking because of the withdrawal of water from aquifers to sustain its population.

"This city is all about commerce, growth and money, and more commerce and growth and money," Ms Wolf, 47, a resident of Houston since 2011, said over the phone.

Coastal cities increasingly face extreme storm and rainfall events, at least in part due to global warming.

Houston has since 2011 tried to switch from drawing underground water to surface water, and use innovative financial mechanisms to pay for drainage.

Hurricane Harvey, though, simply overwhelmed those efforts.

"I have my sympathies, you can't design for that amount of rain," Mr Ani Dasgupta, the Washington- based global director of the World Resources Institute's Ross Centre for Sustainable Cities, told The Sunday Times. But that does not invalidate the lessons.

"There are two things cities can do: Build infrastructure that is resilient to climate and weather events, that might cost 5 or 10 per cent more - which is pretty small compared to the risk; and use green infrastructure like water bodies and spillways to manage weather events," Mr Dasgupta said in a phone interview.

Or take more dramatic action like abandoning some of the most vulnerable areas, giving them back to nature, said Professor Ann Rappaport, a lecturer at the Department of Urban and Environmental Policy and Planning at Tufts University in Medford, Massachusetts.

After Hurricane Sandy, parts of Staten Island, a south-western borough of New York City where houses were flattened by the storm, were bought over by the government. By 2015, almost 400 homes had been purchased, with scores demolished and the area seeded with vegetation.

"A lot more focus on risk management needs to be taken at the municipal level," Prof Rappaport told The Sunday Times. "A lot of threats related to water and storm damage can be managed with some very thoughtful planning ahead of time. That's the fundamental responsibility of government, to protect its citizens."

A version of this article appeared in the print edition of The Sunday Times on , with the headline 'Houston's lessons relevant to Asia's coastal cities, say experts'. Print Edition | Subscribe