Washington, United States | AFP | Rapid, poorly regulated urbanization in Houston has exacerbated the impact of flooding from Hurricane Harvey, experts say, warning that local authorities must pay attention as global climate change threatens to intensify extreme weather events.
A residential and commercial construction boom the Greater Houston area, even in floodplains, that went practically unrestricted has drastically reduced the ability of the area’s soil to absorb rainwater.
At the same time the area saw 42 percent population explosion between 1995 and 2015, to stand at around 4.4 million people today.
To keep apace, some 10,000 hectares (25,000 acres) of swampland and grassy meadows were urbanized, according to research by the Texas A&M University.
The greatest loss of rainwater harvesting areas took place in Harris County, which encompasses Houston, the fourth most populous US city which has seen a 30 percent of its wetlands disappear.
The Port of Houston and its environs, which lies on average thirteen meters (42 feet) above sea level, has lost the capacity to absorb fifteen billion liters (four billion gallons) of precipitation in the event of a tropical storm, according to the study.
Harvey dumped an unprecedented 56 trillion liters, or 1.3 meters (51 inches) of rainfall over the area.
In addition the expanding drainage system, consisting of a network of reservoirs, canals, bayous and roads, was not designed to cope with storms this large.
– Texan individualism –
“There are a lot of industries in Houston so there are a lot of jobs and people, and we don’t have zoning restrictions in place so you don’t have the best planning — and that was one of the shortfalls,” said Joel Scata with the non-profit Natural Resources Defense Council.
Since 2010, at least 7,000 residential buildings have been raised in Harris County on land designated by federal authorities as being at risk of flooding.
Local elected officials both in Houston and Harris County for years have resisted stricter construction rules.
Residents voted three times against the adoption of an urban planning code — even though Houston regularly faces tropical storms and flooding, notably in April 2016 and before that May 2015, which claimed 17 and eight lives respectively.