GONZALES, Texas—Over 500 large oil tanks are situated on the floodplains of the Guadalupe River and its tributaries, crossing one of Texas’ major oilfields. This presence poses significant environmental risks, as revealed by an Inside Climate News investigation.
Residents recall the catastrophic flooding of 1998 before the fracking boom brought booming oil extraction from the Eagle Ford Shale.
A similar event now could have severe consequences, locals fear.
“Tanks full of oil might float away,” noted Sara Dubose, whose Gonzales County ranch has 10 tanks, each with a capacity of 21,000 gallons of oil or toxic wastewater. “Spill all over our land and ruin it for 100 years.”
Dubose’s land could be submerged by nearly 20 feet of water in a repeat of the 1998 flood, based on Inside Climate News analysis from FEMA data.
Satellite imagery was employed by Inside Climate News to map oil tank batteries and infrastructure near the Guadalupe River Basin, identifying potential flood risks using FEMA’s data.
In some areas, the 1998 flood exceeded disaster planners’ worst-case scenarios. FEMA describes this as a “500-year flood,” with a 0.2 percent chance annually. Today, such a flood would submerge 22 tank batteries containing 144 tanks under 10 feet of water, with 12 buried by at least 20 feet, according to ICN’s analysis.
FEMA’s 500-year flood estimates may understate risks as climate change intensifies extreme rainfall.
Dubose, who lived through the 1998 flood, recalls being trapped by rising waters for a week. Current climate trends suggest future floods could be even more severe.
“It’s going to happen,” Dubose warned. “We’re all worried about oilfield flooding.”
Flood-Threatened Tank Batteries in the Eagle Ford Shale
In 2013, a flood in northeastern Colorado overturned 24 tanks, spilling nearly 90,000 gallons of oil and wastewater. During Hurricane Katrina, millions of gallons of oil spilled from supersized storage tanks.
The rules for floodplain construction in Texas fall to local governments, often rural. In Gonzales and DeWitt counties, with about 40,000 residents combined, flooding policy was shaped during the shale boom.
“Such issues are challenging for individual counties to handle,” said Todd Votteler of the Guadalupe-Blanco River Authority, questioning Texas’ commitment to flood avoidance without a statewide policy.
Tank batteries aren’t typically anchored, making them vulnerable to floods, and many pipelines also cross local waterways.
Operators like EOG Resources and Devon Energy have assets in these floodplains. Neither responded to comment requests.
Some areas also contain open pits of drilling waste. Dubose unsuccessfully sued an oil company for contamination from an unlined waste pit on her land.
The Flood of 1998
Blake Muir, a local landowner, described the 1998 flood’s swift devastation. The water overtook landscapes and reached spots now occupied by tank batteries.
“I thought the whole world would flood,” Muir recalled.
The flood was rapid and severe, according to Ben Prause, DeWitt County’s former executive. It covered about two-thirds of Cuero town.
In 1998, the Guadalupe River and several tributaries surged simultaneously, creating an unforeseen disaster.
The Fracking Boom
James Dodson, co-founder of the San Antonio Bay Partnership, noted the rise in oilfield infrastructure since the fracking boom.
“The landscape is very different now,” he commented.
Today, several tank batteries are located in flood-prone areas, some under 20 feet of potential floodwater.
As climate change intensifies rainfall, the risk of catastrophic flooding increases. The Eagle Ford Shale has not yet experienced a major flood since the expansion of oil infrastructure.
Misunderstanding the Risk
Misinterpretations of flood risk are common, explained Matthew Berg from Simfero. The term “100-year flood” does not mean it occurs once a century but has a 1% annual chance.
Probability estimates are limited where data barely cover a century. Rising temperatures increase rainfall intensity, presenting a growing threat.
“We don’t know when the 500-year flood will occur again,” Berg said. “But its likelihood is increasing.”
Climate change has increased rainfall intensity in Texas, as stated in a 2024 report. This trend signals increased extreme precipitation risks statewide.
A Close Call Last Year
If a 500-year flood hits the Eagle Ford Shale, large amounts of oil and wastewater could spill into San Antonio Bay, affecting endangered whooping cranes’ habitats and the Gulf of Mexico.
“It would be unbelievable, the damage it could do,” said Diane Wilson, founder of San Antonio Bay Estuarine Waterkeeper.
Last summer, Dubose feared a repeat of 1998 when heavy rainfall upstream threatened to flood the area. Fortunately, the Eagle Ford Shale was spared.
“It’s a disaster waiting to happen,” said Sister Elizabeth Riebschlager, reflecting on local warnings about flood risks to oil companies.
Original Story at insideclimatenews.org