Houston's Development Boom and Reduction of Wetlands Leave Region Flood Prone

PATTISON — Coffee brown water flows through ditches in rural Waller County, the remnant of storms that drenched the Katy Prairie during Houston's Tax Day flood.

Weeks after that epic rainfall, the prairie is awash in daisies and blue and purple horesemint flowers. Beavers take advantage of ponds brimming with water, and nearby dirt roads show little evidence of being recently inundated.

"This is how the land is supposed to act," said Mary Anne Piacentini, executive director of the Katy Prairie Conservancy, a nonprofit land trust. "It's supposed to absorb water and filter out pollutants. It's not supposed to send it roaring into the rivers and bayous and homes."

In the greater Houston area, though, the staggering increase of impervious surfaces — roads, sidewalks, parking lots, anything covered with asphalt and concrete — has exacerbated the effects of flooding as development in the region has exploded. When land is covered by these surfaces, it loses ability to act like a sponge and soak up water. Things are further complicated in flat-as-a-pancake Houston, where much of the soil is heavily compacted and acts like pavement anyway, sending sheets of storm water to the nearest low-lying area. 

A recent analysis of federal satellite data by the Houston Advanced Research Center for the Houston Chronicle shows that 337,000 acres of 1.1 million acres in Harris County were covered by impervious surfaces in 2011, the most recent year of data. That dwarfs surrounding counties, but the analysis shows many are catching up as the onslaught of development continues pushing from the city farther into the suburbs.

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