Saturday, May 30

Yup, much urban flooding is "pavement" spelled backward

U.S. 290 Freeway at 610 Loop, Houston. Texas

"We really do need to think about continuing to develop the way we have been developing – that is, sprawling cities, lots of concrete, lots of blacktop," he says. "We're putting in so much impervious surface that water runoff becomes one of the major problems we have to address."

I've harped on the same point since I learned that São Paulo's catastrophic flooding this year (and in others) was a kind of optical illusion

The remarks are from a May 29 report for the Christian Science Monitor,  Texas Floods: What can communities do to reduce vulnerability? (+video) by award-winning science journalist Pete Spotts (remember his great reports on the Iceland volcano ash cloud?). Here's the lede:
Cities in Texas are already curbing development along waterways, while other areas are increasingly taking steps, especially in terms of building codes. But the current floods point to a need to inject fresh energy into such efforts, some say.
Spotts was quoting Walter Peacock, director of the Hazard Reduction and Recovery Center at Texas A&M University in College Station.  Texas, I learned from the report, is especially flood prone:
"We can get three, four, five inches in a span of an hour or two," says Philip Bedient, a hydrologist at Rice University in Houston. That rate makes parts of the Lone Star State ground zero for some of the most intense bursts of rainfall in the United States.
For this reason government officials, developers, and community leaders in Texas are very much aware of the need for flood control measures:
Progress in reducing vulnerability to floods is evident in many places around the state, notes Walter Peacock ... Cities are curbing development along waterways, while areas outside city limits are increasingly taking steps, especially in terms of building codes.
"Positive things are happening," he says. "They just are not happening as quickly as many would like."
I'm sure things will be happening more quickly in the wake of flooding that crippled major Texas cities this past week.

There's lots more in the instructive report, which will be of interest to, well, any city dweller who's had bail water, evacuate, or retreat to the roof during a heavy rainstorm.

Every time we've called for more highway or an overpass to ease traffic congestion, or supported a new commercial or housing development, we didn't stop to think how much paving the projects included, and what all that impermeable paving amounted to when it rained hard.

Now we're learning the hard way what it means.

This situation has been going on for a long time; the difference today is that many cities became gigantic to accommodate burgeoning populations and business enterprises -- and transport routes.  So it's like a horror movie; all the paving that went with development began turning into a death trap and a very expensive trap when deluges had nowhere to go.


Flood waters cover Memorial Drive along Buffalo Bayou in Houston, Texas May 26, 2015 


The photo is from a  Reuters report datelined today at 11:55 AM EDT about the latest news on the flooding in Texas. The really interesting part, as it relates to this post, is how little rain is now causing floods. The ground is so saturated, and so many streets are already flooded, that an inch or less of rain can translate into an evacuation notice.

Meanwhile, volunteers in Texas continue to search for people swept away in the state's floodwaters.      
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