Those Who Deny History Are Doomed To Repeat It: Subsidence in 1974 and 2019

My post about Conroe escalating the Montgomery County water wars and putting millions of people in the crossfire from subsidence drew a response from Simon Sequeira, president of Quadvest. Sequiera is one of the litigants arguing for unlimited pumping of groundwater. On Facebook, he dismissively said, “Rehak has an elementary understanding of the issues.”

Who are Simon Sequiera and Quadvest?

Quadvest claims to be the “fastest growing, privately-owned utility company in Southeast Texas.” It has aggressive growth goals. Unlimited pumping of cheap groundwater would help them attain those goals. I consider Mr. Sequeira’s criticism with that in mind. He has some self-interest in this fight. If he wins, he gets even richer. Unfortunately, for millions of people in the Gulf Coast region, money has a short memory.

Denying History Means Learning the Hard Way

The history of Quadvest goes back only 40 years, so this 1974 Texas Monthly article about subsidence may not be part of Mr. Sequeira’s or the company’s institutional memory. William Broyles wrote it. Broyles helped found Texas Monthly and won numerous national magazine awards, one of the highest honors in journalism. Broyles later went on to a distinguished film career as a screenwriter.

The article, titled Disaster, Part Two: Houston, discusses subsidence. It begins with the story of a home – built less than 10 feet above sea level – that had subsided 10 feet in the previous 30 years, three of those feet in just the previous 10 years. The home was separated from the shore and surrounded by sand bags when Broyles wrote the article.

It was one of 448 homes in Brownwood, an exclusive subdivision in Baytown, that actually sank into Galveston Bay.

Cause of Subsidence

In the next paragraph Broyles discusses the cause: “Across the Houston Ship Channel, … the booming plants and industries of the world’s largest petro-chemical complex and the nation’s third largest port had set in motion an inexorable geologic process which destined their quiet neighborhood for the bottom of Galveston Bay. This great agricultural, industrial, and refining economy—and its population—have been fueled by 190 billion gallons of water a year, available easily and cheaply from industrial and municipal wells. These wells have steadily drained the Evangeline and Chicot aquifers (underground water storage systems) faster than they are refilled by annual rainfall. Each year the wells must go deeper to find water. Because of the region’s geology, water is a vital structural component of the clay and sand underlying the land surface; when it is removed, the land sinks.”

One aquifer in Montgomery County is being depleted 500 times faster than its recharge rate. This is clearly not sustainable.

Alternate Doomsday Scenario

Because of its proximity to sea level, Brownwood felt the effects of subsidence first. But the article goes on to discuss the effects of subsidence in the Sixties and Seventies on Pasadena, League City, Clear Lake, the San Jacinto Battle Ground, Galveston, Texas City, and the Johnson Space Center.

The doomsday scenario most feared then and now is a giant hurricane pushing storm surge up the Bay.

The specter of subsidence was so feared by the people of the time that it led to the creation of the Houston-Galveston Subsidence District by the Texas Legislature in 1975, just months after Broyles wrote the article.

Of course, most of Montgomery County is higher than the area bordering Galveston Bay. So why should Montgomery County residents worry?

Red contours show subsidence in last century. Blue contours show subsidence in first 16 years of this century. Note how the small red circle near Jersey Village (A) quickly expanded to the large blue circle around it. Also note (B) the widening gap between red and blue at the top of the frame. This shows that areas that depend on groundwater, i.e., Montgomery County, are subsiding faster than those on surface water, i.e., most of Harris County. Source: Harris-Galveston Subsidence District.

Water level declines start at the well locations where the aquifer is being overpumped.  They call the drawdown curves “cones of depression.” Any local district allowing unlimited groundwater pumping would be impacted first and most. Then the effects would spread to neighboring counties such as Harris and Liberty. This could reduce the gradient of the San Jacinto, causing floodwaters to move slower or accumulate in certain places. Jersey Village is already experiencing this type of flooding due to excessive pumping that put it in the center of a giant bowl.

Fault Activation and Property Damage

Broyles’ article goes on to describe another fear: the activation of faults. “Subsidence caused by massive water withdrawal from regions of high compressibility has also nudged into activity more than 1000 miles of faults. These faults, which generally run parallel to the coast, range in displacement from several inches to eight feet. Such a fault has caused the variation in subsidence at the San Jacinto Monument, where one end of the reflecting pool has sunk three feet and the other end six feet.” 

“This faulting,” continues Broyles, “… exacerbates the problems caused by relatively even subsidence; sewers, pipelines, foundations, sensitive catalytic units, and other highly sophisticated structures cannot survive faulting.”

A recent study by SMU, funded by NASA, confirms that fault activation is still a very real threat from subsidence in Montgomery County.

One economic geologist quoted by Broyles in 1975 characterized faults as “slow motion earthquakes.” There’s no shortage of pipelines, wells, and oilfield instructure. We should not forget that Humble Oil Company turned into one of the world’s largest brands, Exxon, and started right here. Also, there’s other infrastructure like roads, sewers and water distribution networks to be concerned about in northern Harris and southern Montgomery Counties.

Private Vs. Public Interest

If Mr. Sequeira is smart, he will pay close attention to the end of Broyles’ article. Broyles concludes with a discussion of a massive and messy class-action lawsuit between those fighting for unlimited pumping and those whose property was damaged.

Broyles said, “…People … endangered by subsidence are not accepting the extinction of their property … stoically.”

That should give everyone on both sides of the current water war lots to think about.

Many wells and pipelines run through the Lake Houston watershed. Hmmmm. Subsidence, faulting, ruptures, drinking water for 2 million people. It’s easy to see how this could get even uglier. Before there is any resolution, history may repeat itself.

Posted by Bob Rehak on 7/22/2019

692 Days since Hurricane Harvey

All thoughts expressed in this post represent my opinions on matters of public safety and interest. They are protected by the first amendment of the U.S. Constitution and the Anti-SLAPP statute of the Great State of Texas.