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Flood-prone cities like Houston may need to start buying people out, study says

People haven't forgotten the impact of Hurricane Harvey.

A new study calls for preemptive buyouts in flood-prone areas as climate change puts communities at risk. Pictured: Floodwaters surround a home on September 6, 2017 in Houston, Texas. (PHOTO CREDIT: Justin Sullivan/Getty Images)
A new study calls for preemptive buyouts in flood-prone areas as climate change puts communities at risk. Pictured: Floodwaters surround a home on September 6, 2017 in Houston, Texas. (PHOTO CREDIT: Justin Sullivan/Getty Images)

As flooding becomes more and more commonplace across the country as an impact of climate change, a new study argues that strategic property buyouts in flood-prone areas could protect communities by enhancing flood resiliency.

Communities see both environmental and economic gains when cities preemptively buy out properties near one another, especially if those properties are near wetlands or green space, according to new research published Thursday by the Nature Conservancy and Texas A&M University. These areas also benefit from buyouts that occur in advance, the study argues, as opposed to after flooding has taken its toll.

Protecting open space and critical natural resources are becoming important tools with which to mitigate the adverse effects of flooding,” the study notes. “However, land acquisition and buyout programs are almost always initiated in a reactionary, ad hoc manner after a flooding event has occurred.”

The February 28 study probes a common approach to mitigating flood impacts: buyouts instigated by local governments. In the wake of worsening storms and flooding in regions like the Southeast and Gulf Coast, the practice is gaining popularity. But the researchers argue that current buyout methodology fails to account for the social and economic benefits of clustering buyouts, something that could prove environmentally savvy as well.

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“Clustered buyouts provide an opportunity to merge several parcels into one and put the resulting parcel to work as green infrastructure for soaking up and storing stormwater,” Dr. Christine Shepard, director of science for the Nature Conservancy in the Gulf of Mexico, said in a statement.

The study largely focuses on Harris County, Texas, which has the most flood buyouts in the nation. That county is also home to Houston, a city still reeling from Hurricane Harvey’s impacts a year and a half after the storm hit in 2017. Harvey flooded tens of thousands of homes and caused an estimated $125 billion in damage, making it one of the most expensive storms in U.S. history.

CREDIT: The Nature Conservancy
CREDIT: The Nature Conservancy

That unprecedented hurricane presented flood-prone areas nationally with a daunting new reality: as climate change worsens, severe and devastating storms are only becoming more likely. Homeowners have become more open to buyouts in the process, but Thursday’s study finds that governments typically go about the process in a “checkerboard” way, with minimal strategic planning.

Typically, the government mass-purchases homes after flooding has already occurred, and they do so at random, without looking to maximize public benefit or to instill resilience against future storms.

In sprawling cities like Houston, that can create bigger problems — with many buildings clustered together, there isn’t enough open space to absorb a massive amount of water. There is also a significant amount of concrete, asphalt, and other surfaces that resist water absorption. Removing only a few buildings at a time does little to help the wider area’s flood resiliency and it creates dotted spaces that can be economic drains as property values dips.

Thursday’s study offers an alternative approach. Researchers performed analysis of both flood claims and flood loss estimation data, analyzing more than 74,000 homes impacted by Harvey. Of those homes, some 3,500 had also flooded during a number of previous storms, generating hundreds of millions of dollars in damages. They developed a database of distance matrices and losses before investigating various scenarios for buyouts, with an eye toward socially vulnerable areas as well as ecological landmarks.

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In addition to mapping and measuring the proximity of open spaces and the county’s natural features, the researchers evaluated cost effectiveness based on “observed and estimated damages” relating to Harvey. That included flood claim payments under the National Flood Insurance Program (NFIP).

Ultimately, the researchers found that making purchases in clusters — whether preemptively or after storms — would cost the city approximately the same amount financially as their current method of ad hoc buyouts.

But the net gains were stark: clustered buyouts remained a cost effective solution in flood-prone areas while simultaneously creating flood resilient areas capable of absorbing more rain. Using this method, between two and 295 acres could be opened up in Harris County alone, researchers found.

CREDIT: The Nature Conservancy
CREDIT: The Nature Conservancy

 

 

 

 

 

 

 

 

 

 

The findings also encouraged identifying high-risk properties early on, allowing for the execution of buyouts in a planned manner, rather than as a reaction to severe flooding, when the economy is already taking a hit.

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“This is part of building a more resilient community,” Laura Huffman, regional state director of the Nature Conservancy’s Texas chapter, told ThinkProgress.

Noting that “the problem is growing and not shrinking,” Huffman emphasized that the research could be a boon to underrepresented communities, allowing people to sell their homes in advance for reasonable prices before they relocate to less flood-prone areas.

“For me, this way of thinking and this study is trying to shift responses to climate change,” she said, pointing to the ways cities and counties can be more proactive in how they approach extreme weather.

The results of the study are largely specific to Houston and Harris County and they include a few caveats. One major factor in buyouts is resistance from locals unwilling to leave, something the study does not account for. Buyouts are also expensive, especially after major storms like Harvey, and can prove to be a major financial hurdle for local governments.

But Huffman argued the findings can easily translate to other areas and notes that the thought process around climate resilience is shifting, opening up opportunities to increase resiliency nationally. “We did some polling after the flood. I was curious to see where people were in terms of their thinking [in southeast Texas],” she said, referencing Harvey. “People aren’t forgetting this storm [and] this has changed the way that people think about resilience.”

Ultimately, she explained, the impacts of Harvey can serve as a teachable moment for other flood-prone areas.

“Harvey showed us firsthand how climate change is increasing flood risk to coastal communities,” she said. “Investments in natural infrastructure like prairies, wetlands and other forms of open space are a simple approach to get people out of harm’s way and put nature to work for us.”