Harris County Flood Control Doesn't Think Climate Change or Growth Cause Flooding

Past and present leaders of the Harris County Flood Control District do not believe that climate change has contributed to more frequent major rain events in the region or that extensive development has contributed to major flooding.

That’s according to a joint feature published yesterday by the Texas Tribune and ProPublica, which explored the causes of massive flooding in the Houston region and what flood-control officials are doing about it.

While Mike Talbott recently retired as the flood control district’s executive director after 18 years, he gave an interview just before stepping down; in an interview with the Houston Press Wednesday, his successor, Russ Poppe, expressed similar views.

Turns out, Talbott disagreed with virtually everything that the scientists and experts had to say about the relationship between climate change and the frequency of massive rainstorms, and between development and flooding. Instead, he apparently believes that all those scientists just have an “anti-development agenda.”

“Their agenda to protect the environment overrides common sense,” Talbott told reporters.

The Tribune and ProPublica reported that a dozen scientists and experts interviewed for the story —including those from Texas A&M University at Galveston, Rice University, and Texas Tech University —believed Talbott was mistaken (Talbott fired back: "You need to find some better experts... starting here, with me."

Many of the scientists said that the disappearance over several decades of hundreds of thousands of acres of wetlands, which historically have served as floodwater absorbents, has weakened the region’s ability to mitigate flooding. In areas overtaken by concrete and pavement and luxury townhomes, the rainwater has nowhere to go but along the roads and in homes and buildings, scientists said. They also said climate change and global warming are causing torrential downpours to become more frequent.

From the story, here is Talbott’s opinion on all of that:

“The longtime head of the flood control district flat-out disagrees with scientific evidence that shows development is making flooding worse. Engineering projects can reverse the effects of land development and are doing so, [Talbott said]. The claim that “these magic sponges out in the prairie would have absorbed all that water is absurd,” Talbott said.

He also said the flood control district has no plans to study climate change or its impacts on Harris County, the third-most-populous county in the United States. Of the astonishing frequency of huge floods the city has been getting, he said, “I don't think it's the new normal.” …Of the low probability that two 100-year storms hit within weeks of each other, he said, “You can flip a coin and come up heads 10 times in a row.”
Except to say that Poppe agreed with Talbott, Tribune and ProPublica reporters did not feature the new flood control executive director, Russ Poppe, in the story; but Poppe clarified to the Press Wednesday what exactly he does believe and what flood-prevention projects are in the works.

Asked what, if not concrete jungles, is causing flooding, Poppe said, "In many cases, it's how much it's rained and how long of a time frame did that rain occur. For example, when we talk about a one-percent-chance [or 100-year] storm, that's about 12.5 inches in 24 hours. The rainfall amount we observed during the Tax Day floods, that amount of rainfall occurred in 12 hours. Our [drainage] systems just won't be able to handle that volume in that time period."

Poppe added that regulations exist to ensure that developers building in any flood-prone areas take into account all the proper engineering considerations, so as not to increase the flood risk. But many critics, such as those in the Trib/ProPublica piece, are concerned the regulations are unenforced.

On the matter of climate change and whether it is contributing to increased frequency of major rain events, Poppe would not give a definitive answer. Poppe said, "If there’s climate change data that exists showing that the rainfall amounts we use to design our projects are wrong or need to be adjusted, I have yet to see it." (He then also said he believes "there is some legitimacy to climate cycles," which meteorologists use to forecast rainfall or hurricanes each season.)

The rainfall amounts measured by various gauges help the flood control district design drainage systems or flood-prevention projects, such as widening bayous. For example, the standard used to engineer any drainage systems right now is that the system must be able to handle 12.5 inches of rain in 24 hours. Scientists believe that climate change, however, is going to make those rainstorms worse and more frequent.

Asked whether two 100-year storms occurring within weeks may be an indication that climate change is a real concern and the district may need to adjust its rainfall amount standards, Poppe said that in 2007, the flood control district did adjust the numbers, and he will not consider readjusting them until the National Oceanic and Atmospheric Administration finishes evaluating new rainfall amounts for Texas by early 2018.

He also suggested that it is not entirely accurate to say two 100-year storms occurred back-to-back this year. He prefers to call them one-percent-chance storms, believing it is a mistake to believe that if your home gets flooded by the rare storm this year, it won't happen for another 99 years. And, he said, it is not impossible for a one-percent-chance storm to occur twice in the same county, but in different areas within it.

"I know it's a complex concept that folks might have a hard time understanding, but that's the statistical reality that we deal with," he said. "When we start looking at some of the floods that happen, they didn't all necessarily happen within the same exact location."

Perhaps sensing that people who have been repeatedly pummeled by floods this year and last year and a few years before that may disagree, Poppe said, "The idea that 'I've already had two 100-year events this year' — there are some truths to that. There are some areas that did get hit very hard. But it's hard to say there was one specific area that had multiple 100-year rainfall events in one year."
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Meagan Flynn is a staff writer at the Houston Press who, despite covering criminal justice and other political squabbles in Harris County, drinks only one small cup of coffee per day.
Contact: Meagan Flynn