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."