How do cities rebuild after hurricanes like Harvey and Irma? The aftermath of a disaster is often focused on getting back to normal. But do cities need to think harder about how to withstand the next one?
There has been plenty of defiance, loss and uplifting generosity in the wake of Hurricanes Harvey & Irma, but one pressing topic has so far been largely overlooked: How will Houston rebuild in a better way should a storm like this ever again visit?
When you talk about rebuilding a place like Houston, people’s first thoughts are “I want it back the way it was”. But unfortunately that’s not always the best thing to do. As a nation we aren’t planning forward enough. We are developing in places that aren’t suitable or sustainable.
The US places huge emphasis on flood-recovery, rather than flood-avoidance, but in practice has repeatedly bailed-out houses in flood-prone areas that are frequently inundated. At some point a difficult conversation about whether a city needs to be refashioned as it recovers also needs to happen. Prevention is better than cure.
The next phase of recovery is the appropriate time to talk about how to rebuild our cities. Houston will have to think about retrofitting to accept more water and think about its development patterns. The city will have to think about how it manages stormwater and its regulations. It is reportedly severely lacking in sponge-like parklands and is rich in concrete, which has zero absorption qualities and helps funnel water into unplanned streetscape lagoons. The flat terrain of Houston, along with its proximity to the hurricane-spawning Gulf of Mexico, are obvious vulnerabilities.
“In Houston and elsewhere we’ve encroached upon our floodplains and we aren’t leaving any natural environment to slow the flood waters,” said Sandra Knight – a senior research engineer at The University of Maryland. “We build dams and levees and people assume they are safe behind them, or downstream from them. But look at New Orleans – the levees failed.” This challenge facing several cities during a rebuild, is to think about more natural defences to water, rather than simply rely upon ineffective levees and pumps.
New Orleans now has the largest flood barrier in the world – but also emphasizes the need for green, or natural, infrastructure such as grass, woodland and wetlands to soak up water. Innovations such as green rooftops, where plants absorb some rainwater before it’s funneled to barrels rather than on to the street and permeable pavements are also being embraced. There are now seven “rain gardens” in New Orleans – essentially parks where water pools and is absorbed – and the city is spending a further $220m on new green areas that will draw away water that would otherwise end up in the streets or in people’s homes.
Building Codes
Building codes have been tightened up to focus more heavily on flooding. The idea that water must be given space to flow in times of flood isn’t new; the Yolo Bypass was constructed in the 1930s to relieve Sacramento from the severe floods that plagued it. But many US cities are still developing close to low-lying coastal and river areas with barely a nod to what the function of a floodplain actually is.
A 2015 study of six US cities found huge variations in response to extreme weather events fueled by climate change. While New York City and Los Angeles were deemed as making progress, Tampa in Florida was found to be one of the least prepared cities in the nation, with its main hospital – situated on an isolated low-lying peninsula – demonstrative of the lack of preparedness.
“There’s a big variation in how cities are preparing, some are doing almost nothing,” said Sabrina McCormick, an academic at George Washington University.“Houston’s approach is similar to other cities in that it hasn’t looked into the future and taken the risks seriously. Unfortunately we are seeing the ramifications of that.”
Leadership
A new lack of federal leadership is also a problem. The Trump administration has struck down several Obama-era regulations designed to reduce climate-driven risks. Ten days before Harvey struck Houston, Trump tore up a rule that demands federally-funded projects consider climate change and sea level rise before they are built. “Ideally we’d have a national plan to help guide cities toward some basic level of planning to address these risks,” McCormick said. “If we don’t see that leadership, cities will have to look to other cities to figure out where to go next.”
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