Tag Archive for: subsidence damages

Subsidence District to Study Alternative Water Supply for NE Harris County

11/21/24 – Last week, the Harris-Galveston Subsidence District published a request for qualifications (RFQ) for consultants interested in conducting an alternative water supply feasibility study for Northeast Harris County.

Mike Turco, the District’s general manager, said he is specifically focused on the area east of Lake Houston, which is experiencing tremendous growth. The completion of the Grand Parkway has triggered much of that growth. And with it will come increased water demand, which has the potential to trigger subsidence.

“Alternative Water” Reduces Effects of Subsidence

The District defines “an alternative water supply” as a source that does not trigger subsidence. That most often means a source other than groundwater. Subsidence frequently results from excessive groundwater extraction. That can cause compaction of the earth and a whole range of consequences.

Such compaction caused an entire Baytown subdivision to sink into Galveston Bay.

Subsidence can also cause bowls in the landscape that trap water and increase flood risk Subsidence can even change the gradient of streams, slowing water down and backing it up.

An SMU study found that subsidence can cause faulting and damage structures such as homes, roads, pipelines, storm sewers, sanitary sewers and more.

Differential subsidence can create another set of problems altogether. For instance, the rate of subsidence at the Harris/Montgomery county line is much greater than the rate at the Lake Houston Dam.

That has the potential to tilt the lake toward its headwaters. And that could reduce the freeboard factor (feet above flood level) for homes in northern Harris County.

But alternative water sources can reduce all those impacts.

Examples of Alternative Water

In this region, surface water, i.e., from Lake Houston, is the most common “alternative water source,” according to the District’s definition. Lake Houston provides water for more than 2 million people without causing any subsidence.

alternative water source
One example of an alternative water source. Lake Houston from Kingwood’s East End Park. By Dr. Charles Campbell.

So if we already have the major source of water in the area, why look at other alternatives? The planning horizon for water projects is typically 50 years. The RFQ specifically mentions recommendations to meet demand through 2070.

Given expected population growth during that period, the region may need more than Lake Houston. So it behooves us to look at all available alternatives.

According to Turco, right now, the City is already aggressively expanding water distribution from Lake Houston to areas like Spring, which has experienced some of the worst subsidence in the region – 30.5 centimeters, slightly more than a foot since 2007. See below.

The City is also expanding the Northeast Waster Purification Plant and bringing in water from Lake Livingston via the Luce Bayou Inter-basin Transfer Project. But will it be enough to meet demand 50 years from now?

Other alternative sources could conceivably reduce demands on Lake Houston. They include but are not limited to:

  • Building a new reservoir
  • Constructing pipelines from existing reservoirs
  • Using reclaimed water for specific needs, such as irrigation or agriculture
  • Desalination of Bay water

For More Information

A District spokesperson said they want to look at all options, costs and timing. To review the RFQ, click here.

For the District’s latest annual report on subsidence, see this six-page executive summary, this 47-page presentation, or the 307-page full report with appendices.

Subsidence is widely considered to be irreversible. It’s comforting to know that people are already planning for the welfare of our grandchildren.

Posted by Bob Rehak on 11/21/24

2641 Days since Hurricane Harvey

MoCo Groundwater Group Defers Action on Subsidence…Again, Putting Residents at Risk

The Lone Star Groundwater Conservation District (LSGWCD) board once again deferred action on subsidence at its three-hour board meeting on 2/9/2021. The ostensible reason: public confusion on the issue, although that confusion may have been caused by the District’s own staff.

Several board members also launched ad hominem attacks against critics, alleging they were deliberately spreading misinformation about the board’s position on subsidence. They demanded public apologies from critics after the District’s own staff made misleading presentations.

Confusion Starts when General Manager, Counsel Fail to Articulate Real Issue

At about 59 minutes and 35 seconds into the video, Samantha Reiter, LSGWCD’s General Manager, summarizes consultant James Beach’s testimony to GMA-14. She did not explicitly mention the exact text of his statement about LSGWCD’s position on subsidence to GMA-14. Specifically he said, “At this time, we can’t support the use of DFCs for subsidence in Montgomery County.” 

Reiter’s lack of specificity teed up a wandering, confusing and mind-numbing 90-minute presentation by Stacy V. Reese, LSGWCD’s General Counsel.

She designed the presentation to address one of the criticisms leveled against the board by critics, i.e., that a potential violation of the Open Meetings Act had occurred. According to LSGWCD watchers, LSGWCD’s board never openly authorized Beach to make that statement, which seemed to state a conclusion the Board had reached. That raised the questions, “Who authorized the statement and when?” But those were not the questions Reese addressed.

Reese’s Presentation a Masterpiece of Misdirection

Without mentioning Beach’s statement upfront or accurately summarizing critics’ concerns, Reese then tried to show that LSGWCD had investigated subsidence since 2017. But everyone already knew that. And that made a presentation which took up about half the meeting largely irrelevant while the audience drifted away.

Instead of addressing who authorized Beach’s statement and when by reviewing the LSGWCD January 12th meeting and the GMA-14 January 20th meetings, Ms. Reese instead discussed other board meetings and presentations dating back to 2017. Repeatedly skipping forward and back in time and between LSGCD and GMA 14 meetings, her presentation included so much irrelevant information, it became impossible to determine the board’s position on subsidence. One understood only that they had previously discussed it.

Not until two hours and sixteen mininutes into the meeting does Ms. Reese allude to Mr. Beach’s statement to GMA-14 about rejecting subsidence as a metric in DFCs at the bottom of a slide with eight bullet points. But she summarizes the slide in one sentence: “We’re adapting to a subsidence statement.” In other words, she shows one thing and says another.

Then she claims at 2:17 that the board has not yet voted on a final position re: DFCs or subsidence.

If you didn’t know that the real issue was Beach’s statement, you might conclude from Reese’s presentation that the board was, in fact, supportive of including some sort of a subsidence statement in Desired Future Conditions. That’s the opposite of what Beach said.

Laying the Groundwork for Backpedaling?

Ms. Reese did, however, lay some groundwork for a possible reinterpretation of Beach’s statement. Although she didn’t say it outright, she implied that measuring subsidence was unnecessary because it varies with groundwater pumping rates. While a correlation does exist at times between the two variables, the assertion masks two important points:

  • First, without measuring subsidence, you cannot calibrate the accuracy of groundwater-pumping models.
  • Second, groundwater levels are reversible; subsidence is not.

The latter point deserves explanation.

Groundwater Levels Reversible; Subsidence Not

The amount of groundwater depletion depends on pumping and recharge rates. Those can vary annually depending on usage and rainfall.

But while water-well levels can rebound, subsidence cannot. Subsidence lasts forever. Once clay collapses, it stays compressed. It’s like trying to re-inflate a brownie that you’ve smashed with a sledgehammer.

Not Adopting a Subsidence Metric Would Allow Board to Defer Action on Groundwater Withdrawals for Decades

Putting these facts together, you can see how a LSGWCD board intent on unlimited pumping could cause lasting subsidence and severe damage to homes throughout the region. In a 70-year plan, they could argue through Year 60, for instance, that aquifer levels would bounce back. Without a subsidence metric in place as a check on pumping, they could continually kick the can down the road. They could say year after year that they will change regulations at some point before Year 70 to restore aquifer levels to their targets.

Mr. Beach stated this explicitly during the board meeting. At approximately 2:31 into the video, he says, “We can incorporate subsidence in the future…”

At 2:32, Jim Spigener, LSGCD’s Treasurer says it, too. “It feels like there is a rush to do something. But DFCs are a 70-year process. The danger is that we do something in the heat of a political storm and it’s the wrong thing. We’re not in any hurry to figure out how to do this right. We’re not going to figure this out in a month.”

Righto! Ms. Reese’s presentation must have put him to sleep, too. According to her, LSGWCD has worked on this since 2017.

Finally, at 2:34, someone makes a motion to table any action on desired future conditions. The motion passed. Neither did the board consider Phase Two of their subsidence study. See 2:49 of the video.

More Questions than Answers Come from 3-Hour Meeting

Reese’s inventory of subsidence discussions skips from LSGWCD board meetings in May and June of 2020 to the GMA-14 meeting on January 20, 2021, leaving a critical six month gap. (See 2:16 in video.)

Without speculating on the motives of individuals, I would point out that actions speak louder than words. The inability or unwillingness of highly intelligent people to clearly articulate issues and address them in a straightforward manner raises many questions.

  • Why?
  • Why delay?
  • Why defer action?
  • Why not clarify the differences between measuring aquifer depletion and subsidence?
  • Why not elaborate on Beach’s statement for video posterity?
  • Why spend 90 minutes rehashing old board meetings and not one minute articulating a clear subsidence goal?
  • Who does the LSGWCD board represent? Residents or Quadvest?

These are important questions. Much depends on them. Perhaps even billions of dollars in potential damages.

Types of Damage Subsidence Can Cause

Differential subsidence across a county can cause bowls to develop in the landscape, such as near Jersey Village, which increases flooding. (See subsidence map below.)

The subsidence map below also shows something else. At the rate LSGWCD wants to pump, it could cause southern MoCo and northern Harris Counties to sink two feet relative to the dam at Lake Houston. Picture tilting a full bathtub two feet. Something will get wet!

Models show that excessive groundwater pumping in MoCo could create 3 feet of subsidence in Kingwood compared to 1 foot at the Lake Houston Dam.

SMU also found that subsidence triggered geologic faults in Montgomery County that have damaged homes.

Insurance companies have also linked subsidence to:

  • Damage to infrastructure such as roads, sewers and buried utilities
  • Foundation, sidewalk, driveway, roof, and brickwork damage
  • Cracks in plaster, wallboard, flooring, ceilings, windows, and moldings
  • Doors and cabinets that refuse to open or shut properly

In some cases, homes may not even be repairable.

Slow Rate of Subsidence Masks Magnitude of Problem

The biggest problem with the subsidence problem? With a few exceptions, such as fault-line triggering, it happens over such a long period of time that many homeowners will never fully experience it.

Median duration of homeownership in the U.S. is 13 years. But in The Woodlands and Houston, owners typically stay in a home just 10 years.

National Association of Realtors

At that rate, most people might not notice subsidence. I’m an exception, I’ve lived in my house almost 40 years. Stick around that long and you get a true feeling for the cost of subsidence. I’ve had my foundation leveled twice; my driveway repaved twice; my sanitary sewer lines repaired twice; my doors and windows replaced once; and my walls, cabinets, and ceilings repaired multiple times.

You don’t need to remind me about the true cost of subsidence.

Posted by Bob Rehak on 2/10/2021

1261 Days since Hurricane Harvey and 510 since Imelda

The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.