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Hurricane Harvey has been downgraded to a tropical storm, but the devastation is showing no signs of easing. Flooding has killed at least 38 people, and many more are missing, stranded, and newly homeless. The total human impact won’t be known until the floodwaters recede and rescue crews can start going door to door (where doors and houses still exist).
There is debate about how much to blame climate change for the development of Harvey, but there seems to be consensus that the storm is more calamitous than it would have been without climate change (due to warming ocean temperatures and sea level rise). More than 50 inches of rain have already fallen in some areas, setting a new record for rainfall from a single storm in the continental U.S.
One factor that has amplified the destruction, mentioned over and over again, as you’ll see below, is the massive growth in the human population and the development that goes along with it. Houston, the country’s fourth largest city, with 2.3 million residents, is also the fastest-growing city in the United States. And the greater Houston metropolitan area is home to more than 6.5 million people. It would follow, then, that population planning would be part of the disaster mitigation strategy. Alas, that level of foresight is not profitable in the short term and it doesn’t help politicians get elected, so it is largely ignored.
What follows are selected excerpts from stories that have linked population growth with Harvey’s crippling impact.
Houston’s population has exploded in recent years. At nearly 2.4 million people, it is now the fourth largest city in the country. If you include the rest of surrounding Harris County, that number goes up to more than 4.5 million.
“When you’ve got rapid growth and development, along with that comes roadways, rooftops, and parking lots,” says [Sam Brody, a professor at Texas A&M, Galveston].
Because Houston lacks a zoning code, builders aren’t required to use flood mitigation techniques like green areas to absorb rainwater or retention ponds for runoff.
According to Brody, “all of that impervious surface makes it very difficult for the water to drain into the soil. Instead, it runs into the bayous and, in this case, into people’s homes.”
Brody adds that a lot of those roads, buildings and parking lots have been built up over grass and prairie lands to the west of the city.
“That compromises the natural infrastructure of this very flat and low-lying landscape, making it difficult for the water to absorb and be held by the prairie and the wetlands, and slowly release into Galveston Bay.”
Though its breakneck development culture and lax regulatory environment have been lauded for giving working people affordable housing — and thus a shot at the American dream — many experts and residents say that the developers’ encroachment into the wetlands and prairies that used to serve Houston as natural sponges has inevitably exacerbated the misery that the city is suffering today.
The post-Harvey rebuilding drama here is bound to unfold as a frontier nation increasingly faces up to limits — as southern and western cities mature, as resources are strained by a growing population, and as climate change, exacerbated by Houston’s signature industry, threatens bigger, wetter, ever-more-dangerous storms.
Though the region suffered some tough years after the 1980s oil bust, Harris County, which includes Houston, experienced the highest annual population growth of any county in the United States in eight of the last nine years, according to census data.
The most recent urban devastation that comes to mind would be Hurricane Katrina. But the growth trajectory of New Orleans in 2005 is not a model for Houston in 2017. The population peak of New Orleans was in 1960, 45 years before Katrina. New Orleans is an important, iconic city for a variety of cultural and industry-related reasons, but it never adopted the model practiced in Houston, Dallas, Atlanta and other Sun Belt metro areas: sprawling, cheap housing and fast population growth. As New Orleans rebuilt, its task was primarily about fixing what had been broken rather than planning for endless population growth.
Since 2010, the Houston metro area has accounted for a larger share of U.S. population growth — six percent — than any other metro.
Houston’s population climbed to 2.2 million in 2015, a 25 percent increase from 1995. Harris County had an even bigger bump over that time, 42 percent, and now has 4.4 million residents. As the population grew, the city expanded, covering fallow land that had served as a natural sponge.
Between 1992 and 2010, 30 percent of the surrounding county’s coastal prairie wetlands were paved over, according to a 2010 report from Texas A&M.
Projects to widen the bayous and build thousands of retention ponds for excess water have not kept pace with the new rooftops, roadways and parking lots needed to accommodate about 150,000 new residents a year, experts say. As a backup, roads were built below grade and designed to take on excess water when storm drains overflow.
When Hurricane Ike raged through Houston, it was 2008 and the metro area was close to a million people smaller. Today, it’s one of the fastest-growing metro areas in the country.
Corpus Christi’s population, too, has risen steadily in recent years.
Texas’ cities and their ballooning suburbs have been on an economic tear.
Houston is a rapidly growing city. Millions of people have moved there, spurring growth and development, much of which is on land that used to absorb water—now it’s paved over, creating more storm runoff.
Neena Satija, investigative reporter for the Texas Tribune and for the public radio program, Reveal, says Houston isn’t ready for a hurricane like Harvey.
She says the combination of population growth, increased development, and insufficient planning by local government primes the city for major problems when it comes to handling a deluge of rainwater.
Houston is also known for its lax zoning laws, and Satija says city officials don’t buy into the idea that increased development is creating a greater risk for flooding. She says scientists say otherwise.
“The scientists are very clear on this; there seems to be no debate. What’s happened in Houston in terms of development and population growth has increased its risk of flooding,” she says.
Many more people now live in the path of a storm. Corpus Christi is a crucial oil-refining center, and the nation’s fifth busiest port. Add in the Houston Ship Channel, another major petrochemical industry center, and the risk of an environmental disaster or a major disruption to energy supplies gets larger. Harris County, home to Houston, is the nation’s second fastest-growing county. Population growth brings with it new developments, some of them in vulnerable places.
The brunt of Hurricane Harvey is projected to miss Houston, but the sprawling metropolis is likely to face massive flooding from its third crippling storm in the past three years.
It underscores a new reality for the nation’s fourth-largest city: Climate change is making such storms more routine. Meanwhile, unchecked development in the Houston area is wiping out the pasture land that once soaked up floodwaters.
How bad things get in Houston depends on where and how quickly the rain falls. But many are already drawing comparisons to 2001’s Tropical Storm Allison—the worst rainstorm to hit an American city in modern history. Allison dropped 40 inches of rain on the city in five days, killed nearly two dozen people, and caused $5 billion in damage in the county that includes Houston.
A flood in April 2016—nicknamed the “Tax Day” flood because it fell on the deadline to file federal income taxes—paralyzed northwestern portions of the city and surrounding suburbs. Those areas have exploded in population in recent years.
“More people die here than anywhere else from floods,” Sam Brody, a Texas A&M University at Galveston researcher, told us last year. “More property per capita is lost here. And the problem’s getting worse.”
Many scientists, experts and federal officials say Houston’s explosive growth is largely to blame, along with climate change. As millions have flocked to the metropolitan area in recent decades, local officials have largely rejected stricter building regulations, allowing developers to pave over acres of prairie land that once absorbed large amounts of rainwater. In the decade after Tropical Storm Allison, about 167,000 acres were developed in Harris County, home to Houston.
As the region’s population grows, more and more of southern Texas is being paved with impermeable surfaces. This means that when there is extreme rainfall the water takes longer to drain away, prolonging and intensifying the floods.
Hurricane Harvey is likely to end up being one of the most costly disasters in U.S. history. It is also likely that climate change and population growth in the region have worsened the effects of this major storm.
One underlying cause of Houston’s suffering is that developers and town officials in Harris County, which contains Houston, have for years advocated the development of the wetlands and prairies around the city—land that had long served to absorb the rainwater that now overwhelms the region’s sewers and streams every year. The flood-absorbent grasslands of the Katy Prairie have been cut by three-quarters over the past few decades as Houston sprawled west. The state played along, funding expansion of I-10, “the Katy Freeway,” and another road, the Grand Parkway, which further opened that land up for development.
The degree to which storms become “disasters” is determined, at least in part, by factors beyond wind speeds or rainfall numbers … One major contributor is “how many people and buildings are in the wrong place at the wrong time.” On this front, the situation in Houston could hardly be worse.
As the population has boomed across this Sunbelt city in recent years, an increasing number of people and buildings find themselves in a vulnerable position. Meanwhile, thousands of acres of wetlands that might have helped absorb excess rainfall have been gobbled up by development. When paved surfaces can’t perform the crucial work of stormwater retention, “even lesser storms are invested with more destructive power,”…
“There’s been a 23 percent population increase [in Houston since 2001]. There’s been miles and miles of new pavement and structures put in harm’s way. Allison was one of the most devastating storms of all time in the United States. This is going to be much worse, if something with that much rainfall sits over Houston for a couple of days.
Houston has a large amount of pavement—impervious surface—put down in a very low-lying, flat area that experiences heavy rainfall events. I tell my students that the problem is complicated; there are lots of underlying factors. There are physical conditions. There’s environmental change increasing these heavy rainfall events. There’s sea level rise and changing temperatures. All of those are small, slow-moving gears as part of this overall problem. The bigger gear moving much faster is human development—the built environment. Houston added 100,000 people last year alone. That set us up for this potential catastrophe.”
– Samuel David Brody, director of the Center for Texas Beaches and Shores at Texas A&M Galveston