Why Was the Houston Flood so Massive? Flood Engineers Speak Out

A combination of the location of the City of Houston at the confluence  of multiple rivers and bayous, booming growth generally unchecked by  regulation, and record amounts of rain that was enough to swamp any  community is blamed for the devastating flooding that has drowned the  nation's fourth largest city, according to experts in flood plain  management, News Radio 1200 WOAI reports.

 "It was a massive amount of water, and the creeks and bayous filled up  and the water couldn't get out fast enough," flood expert John Espinoza  said.  "Water starts falling and the city is so flat that it starts  ponding.  There is very slight elevation." 

He says in most cities in Texas and around the country, flood waters can  flow down streams and stay moving, but in Houston the water that falls  simply stays in place.  He says living in Houston is like 'living on a  cookie sheet.'

 But Roy Sedwick, executive director of the Texas Floodplain Management  Association and a former FEMA flood expert, says the growth of the city  also played a role in Hurricane Harvey's powerful impact. 

"There was some good planning early on, good development that was safe  and out of the flood plain," he said.  "But as the development  progressed in the upper watersheds north and west of Houston that  development created more runoff, so properties that used to be be out of  the flood plain are now in the flood plain." 

He says Texas, with its historic opposition to local regulation, does,  for example, not allow counties code enforcement authority, and many  major Texas cities, including Houston, have sprawled beyond their city  limits.  A new law, just passed by the Texas Legislature this summer, to  severely restrict the ability of a city to annex unincorporated areas,  will only make the situation worse. 

"You get out into the county, there's no regulation," he said.   

The flood management engineers say the key to Houston avoiding a repeat  of Harvey, and Tropical Storm Allison, which caused serious flood damage  to Houston in 2001, is to require all damaged structures which are  being rebuilt to be elevated. 

"It should have to be elevated to the current maps and the current hundred year flood plain," he said. 

He said FEMA also has some responsibility to update its flood plain  maps, and developers and regulators must agree to follow regulations  even stricter than those required by FEMA and by the Federal Flood  Insurance Program.

 Espinoza says development creates what is called 'impervious cover,'  which is generally concrete slab foundations which don't absorb rain  water, leading to increased runoff and occasionally directing that  runoff away from what would otherwise be its natural course. 

Sedwick says for Houston and other communities, the devastation of  floods can be eased by creating more green space where water can flow  freely. 

"There is a new expression for this, 'no adverse impact'," Sedwick  said.  "The concept is 'we want your development, we need your  development, we want the economy to grow in our community, but we don't  want to grow at the expense of everybody else.'  That means the  developer must minimize runoff, create low density development,  eliminating as much of the impervious surface as you can." 

He cites, for example, commercial parking lots that actually have to be mowed, because the water is allowed to soak through. 

"You have to allow the water to run its course." He says some developers, for example, have begun to market homes, in  addition to by bedrooms, bathrooms, and square footage, as 'out of the  flood plain,' a positive development. 

And Sedwick also blames people for becoming disconnected with the  natural forces of nature, thanks to today's electronic overload.  He  says individuals need to check their homes and their businesses, insist  that they be out of frequently flooded areas, and take steps that are  necessary to protect the processes of nature which allow for water to  run off naturally.  He says if buyers won't buy homes and commercial structures that are in  easily flooded areas, developers will stop building them. 

"I remember hearing a story from the 19th Century about the Indians  camped on the banks of the Brazos River," he said.  "A cavalry officer  suddenly saw them pack everything and start to move out, and he asked  what was happening.  He was told 'when the crickets run up the hills,  when the snakes crawl up the hills, when the birds fly to the high  trees, its time for the people to go up the hill.'  We have lost our  inborn connection with nature."

IMAGE: GETTY

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