Flooding in Central, South Texas Put Layers of Climate and Economy on Display
June 10, 2015—From infrastructure to climate change, the disaster impacts areas of daily life. The month of May saw heavy, concentrated thunderstorms dump immense amounts of rain onto the Texas Hill Country and southeast Texas, causing historic flooding in both Austin and Houston. The floods have caused several deaths and will undoubtedly result in millions of dollars in property damage throughout the state. Residents have been rescued from both their homes and vehicles.
“We were out of town until Tuesday and luckily missed it all,” said alumna Jill Sanders-Smith, who lives in the Briar Grove section of Houston just west of the Galleria, which sustained heavy flooding. “We were lucky our home wasn’t flooded. The neighborhood we lived in when we first bought a home flooded and a bunch of our old neighbors had several feet of floodwater. My husband’s parents’ house in Memorial had a few inches of water inside as well.”
While the cleanup begins, so will the questions. Could anything have been done to prevent this, and could it happen again?
Texas Tech University experts say simply increasing protection against a flood is not as simple as it sounds, and with the way the climate is changing, flooding of this magnitude may increase.
The solution sounds simple. To prevent flooding just improve the infrastructure to where it can handle larger amounts of floodwaters. There’s only one problem – the cost.
“When you talk about protecting against natural disasters, the costs become huge,” said Ryan Williams, an assistant professor in the Department of Agricultural and Applied Economics who studies water resources and economics. “You could say Houston should just go ahead and increase taxpayer money to make sure it doesn’t happen again, and it is terrible that people have lost their lives and businesses have been shut down. But that doesn’t make economic sense.”
Williams said simply increasing protection against flooding goes beyond just improving infrastructure. Land development near creeks, rivers and watersheds also has a tremendous effect, possibly even changing the direction water from rain runoff flows.
“As we build out space for people to live we use concrete, and as we do that in creates change in the dynamics of stormwater runoff,” Williams said. “It’s possible that water would naturally flow where it is flowing, or it’s possible we have, through manmade activities, changed the flow of water. “Maybe we’re causing part of the problem ourselves.”
As subdivisions are built, contractors could factor flood protection into the cost and protect against the worst-case scenario for the rain event that comes once in 100 years. But in ramping up that protection, the cost gets passed to consumers and into the price of the homes, and that could be something many home buyers aren’t willing to stomach.
“The amount of rain Texas received this month is an anomaly,” Williams said. “My guess is it is at least a once-in-50-years total rain event for the state. It’s just not economically feasible to build infrastructure for these rare, low-probability events.”
Steve Cobb, a meteorologist and an instructor of atmospheric science in the Department of Geosciences, said this rain event reminds him of Tropical Storm Allison in 2001 which hit Houston and killed 23 people while causing $9 billion in damage.
While he said this series of storms is not nearly of that magnitude, the amount of rain and the rate at which it came down was equivalent to some longer lasting Tropical rain event.
“They had two or three inches of rainfall in an hour and a half, or maybe more than that in a lesser period of time in some locations,” Cobb said. “When you get an intense rate of rain, the ground is not able to absorb it, and it runs off into these tributaries, creeks and streams and they become swollen.”
Cobb said a big factor in the flooding in both Austin and Houston was that the storms formed and moved repeatedly or very slowly over the same area. The continual rainfall quickly outpaced the ability of the natural streams and urban drainages to carry the water away resulting in significant flooding for the Hill Country and South Texas.
Luckily, Cobb said, the long-range forecast calls for a slow drying trend over the next two weeks which eventually will lower the potential for widespread thunderstorms that could further exacerbate the situation.
Speaking of exacerbating the problem, that’s where climate change could play a huge factor in the long-term situation.
While climate change didn’t specifically cause the flooding, Texas Tech climate change expert Katharine Hayhoe, an associate professor in the Department of Political Science and director of the Texas Tech Climate Science Center, said it is playing a role in the intensity of the storms and amounts of rain produced as well as affecting water runoff.
“As the atmosphere warms – and every season in Texas has been warming since the 1950s – more water evaporates from oceans, lakes, reservoirs and streams,” Hayhoe wrote on her Facebook page. “When a storm comes along, there’s more water vapor in the atmosphere available for that storm to pick up and dump. Heavy precipitation has increased as a result.”
Hayhoe said there hasn’t been much of a change in annual average rainfall for Texas, noting East Texas has gotten a little wetter and West Texas has gotten a bit drier, and the expectation is for that trend to continue. But that can also mask the fact that, throughout the U.S. and Texas, day-to-day precipitation is becoming more extreme.
“Just to be clear, science does not say climate change is causing the extreme rain and drought we’re seeing across the U.S. today and in recent years,” Hayhoe wrote. “Just like steroids make a baseball player stronger, climate change exacerbates many of our weather extremes, making them, on average, worse than they would have been naturally.”