Urban flooding from storms doesn’t need to be so bad
Recent natural disasters in U.S. urban areas have also been manmade disasters.
In 2005, the failure of New Orleans’ levees and the destruction of Louisiana’s wetlands magnified damage from Hurricane Katrina.
Last week, too much concrete, too little planning and too little respect for nature’s capacity to absorb water left Houston and its sprawling suburbs all the more vulnerable when Hurricane Harvey deluged the region with record-shattering rains.
To be sure, no city — regardless of planning or natural buffers — could have withstood such an onslaught of water without flooding. Harvey dropped an average
36 inches of rain over five days and nearly 50 inches in a few places. But the damage didn’t have to be as bad as it was, nor should Houstonians have had to suffer through two other crippling floods since May 2015.
Houston starts with some natural deficits. It’s flat. It’s rainy. It has hard clay soil, which doesn’t easily absorb water. All the more reason to employ well-known strategies to minimize flooding. Instead, such strategies were mostly ignored during a decadeslong building binge that turned the Houston metro area into the
5th largest in the nation, home to nearly 6.7 million people.
Also disregarded was a 1996 report by county engineers, un- earthed this week by The Dallas Morning News. The report warned that Houston’s two huge reservoirs, if not upgraded or provided with new underground drainage, would someday add to flooding. And that’s precisely what happened during Harvey. When the reservoirs threatened to overflow, authorities opened the floodgates, releasing a torrent into nearby neighborhoods.
Defenders of Houston’s relentless growth dismiss scientists and engineers who champion new approaches as anti-growth, prozoning elitists who look down on Houston’s boomtown building style. But most critics aren’t against all growth. They’re in favor of smarter growth, which re- quires new building strategies.
Among the most urgent are preserving prairies and freshwater wetlands, which absorb water, and including detention ponds and open green spaces to contain runoff in new communities.
According to a Texas A&M analysis, from 1992 to 2010, Harris County, which contains almost all of Houston, lost 15,855 acres of wetlands — an area nearly 19 times the size of New York’s Central Park. To change this pattern, “I would not advocate zoning,” says land use expert Samuel Brody of Texas A&M. “We need to grow … with more common sense.”
Getting Houston’s leaders, developers and even some residents to buy into such changes won’t be easy, but without them the city’s future growth will be at risk.
In New Orleans, the answer was rebuilding levees and erecting huge barriers to keep out storm surges.
In Houston, for a storm like Harvey, “it is more about building places for the water to go,” says Rice University engineering professor Phil Bedient. Residents of the sprawling metropolitan area will have to learn that working with, not against, nature can make floods less frequent and far less catastrophic.
That’s a lesson not just for Houston but for cities in the path of Hurricane Irma as well.