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Is The Ground Falling? Should We Care? Part 4 Of 4: LSGCD, Property Rights advocates present their view of subsidence

Is The Ground Falling? Should We Care? Part 4 Of 4: LSGCD, Property Rights advocates present their view of subsidence

Image: The wild chicken, free of man’s forced regulation and breeding, is a beautiful creature. (Yes, it’s a male but it’s a male chicken.)

Conroe and Montgomery County, July 6 – Subsidence is real. There’s a fair amount of agreement that the data showing subsidence is accurate, particularly for Harris and Galveston counties and for south Montgomery County. There is some relationship between groundwater production from some aquifers and subsidence.

That’s where the agreement between the advocates of surface water, such as San Jacinto River Authority General Manager Jace Houston, and property rights advocates or advocates of a wider choice of water sources, including groundwater, seems to end.

Over the past week, The Golden Hammer sought data, analysis, and opinions on the subsidence issue from officials with the Lone Star Groundwater Conservation District in Conroe and from property rights advocates associated with Restore Affordable Water (RAW).

An Important Stratigraphic Note

The following figure is a hydrogeologic section, courtesy of the United States Geological Survey (USGS) of the Gulf Coast aquifer system and rock strata shown trending southeast to northwest from Galveston County, passing through Harris County, passing through Montgomery County, and ending in Grimes County. Like they would towards any government bureaucracy, citizens must view scientific data warily. Nevertheless, the USGS has a remarkable team of scientists. Some of the greatest geological research in the world continues to occur at USGS. From remarkable petrologist E-An Zen who worked as a research geologist for USGS from 1959 to 1989 to the geologists and geochemists who have shifted the focus of USGS largely to hydrogeology in current times, USGS has engaged in research at the highest level of quality.

Source: USGS.

This discussion is important for all citizens to know and understand. If you’re bored with the four paragraphs, please feel free to skip to the summary which appears in the inset below, although the information in those four paragraphs is also important.

Close to the Gulf Coast aquifers from which groundwater production has historically occurred are the Chicot acquifer and the Evangeline aquifer. Both the Chicot and Evangeline are largely silty sandstones. Water from the Chicot tends to be a bit more briny and lower quality than Evangeline water. Since the Evangeline goes to about 3,200 feet in depth at the Harris-Galveston County line, realistically there is little groundwater production from deeper formations in those areas.

At the base of the Fleming Formation is a large aquifer known as the Jasper. The Jasper section of the Fleming Formation is a complex interceding of sands, silts, and clays with some mixing of volcano-clastic and tuffaceous material which scientists believe came from volcanic activity in the Davis Mountains during the Miocene epoch. The Jasper is mostly sandy fluvial (river) and floodplain deposits, which, through diagenesis, became sandstone and siltstone.

What discussions about groundwater aquifers and subsidence often fail to mention, however, is a stratigraphically important layer which tapers in thickness as one moves northward. This layer is the Burkeville Confining Unit. The Burkeville is much less sandy that the Jasper and consists largely of clays and some silts. Scientists believe the Burkeville Confining Unit formed in a lagoonal setting.

The reason the Burkeville has the name “Confining Unit” is because it is just that. It’s a harder stone which has much lower porosity and is far less likely to experience longitudinal shifts, which appear at the surface of the Earth as subsidence.

The Golden Hammer isn’t trying to put readers to sleep with this brief discussion of stratigraphy. Rather, citizens of Montgomery County should have a firm understanding of the importance of the Burkeville Confining Unit, which is approximately 2,000 to 1,200 feet in depth from the surface of the Earth in Montgomery County. Basically, it is unlikely that geologic formation at and below the Burkeville would subside, because the Burkeville Confining Unit is structurally sound and does not exhibit longitudinal shifting.

The Golden Hammer isn’t trying to put readers to sleep with this brief discussion of stratigraphy. Rather, citizens of Montgomery County should have a firm understanding of the importance of the Burkeville Confining Unit, which is approximately 2,000 to 1,200 feet in depth from the surface of the Earth in Montgomery County. Basically, it is unlikely that geologic formation at and below the Burkeville would subside, because the Burkeville Confining Unit is structurally sound and does not exhibit longitudinal shifting.


This slide is actually quite important. It shows Montgomery County right in the middle of the white area. The slide is the United States Geological Survey’s Houston Area Groundwater Model (HAGM) projection of subsidence from groundwater production from the Jasper aquifer. USGS projects little to no subsidence, which is the reason the map is all white. In cooperation with the Harris–Galveston Subsidence District, Fort Bend Subsidence District, and Lone Star Groundwater Conservation District, the U.S. Geological Survey developed and calibrated the Houston Area Groundwater Model (HAGM), which simulates groundwater flow and land-surface subsidence in the northern part of the Gulf Coast aquifer system

USGS’s projections shown in the Houston Area Groundwater Model (HAGM) clearly are in accord that production of groundwater from the Jasper aquifer is very unlikely to cause subsidence. Montgomery County appears in the center of the white area shown on the HAGM map and appears entirely in that area, meaning Jasper groundwater production would not cause subsidence, according to the scientific studies of USGS.

Lone Star Groundwater Conservation District Vice President Harry Hardman.

Harry Hardman, Vice President of LSGSCD, seems to agree with that conclusion and told The Golden Hammer:

“I do think subsidence is something to be concerned about in the Gulf Coast region, but history has shown that this issue is much more significant further south and closer to the coast than we are in Montgomery County. If you had attended the GMA 14 meeting last week, you would have heard from Mr. Mike Turco, General Manager of the HGSD, who said that one of the challenges of predicting subsidence in Montgomery County is the fact that there has never been any coordinated measurement to really determine how much (if any) has actually occurred over time which would be a helpful indicator for potential further effects. To do so is extremely expensive – the measuring equipment used to do these measurements (Borehole Extensometers) are extremely expensive (approximately $1 million each), which is way above the budget of LSGCD.

“Also, another HUGE issue with subsidence in southwest Montgomery County is the extensive groundwater pumping by Harris County just south of the county line. Since Harris County pumps over 5 times the amount of groundwater that Montgomery County does – primarily out of the shallower Chicot and Evangeline aquifers (which are more susceptible to compaction than the Jasper, Montgomery County’s primary aquifer), the real question is how much is Harris County contributing to our subsidence? How much will it be a factor if/when Harris County does their final conversion to surface water, thereby significantly reducing the draw overall. Given the number of wells and the amount of pumping going on in northwest Harris County, that should be a major area of focus.”

Lone Star Groundwater Conservation District

The Lone Star Groundwater Conservation District (LSGCD) shifted from an appointed Board of Directors to an elected one when voters chose the entire Board on November 6, 2018. A pro-property rights group of seven (7) directors came into office. All seven had received the endorsement of a pro-property rights citizens advocacy and education group known as Restore Affordable Water (RAW), whose Board consists of Quadvest President Simon Sequeira, real estate investor Michael Stoecker, and Bill O’Sullivan, also known as “The Sage of Montgomery County.”

This newspaper has been somewhat critical of recent actions by LSGCD’s elected Board to require its consultants to execute Confidentiality and Non-Disclosure Agreements. The particular source of that criticism is that subsidence, in particular, is an issue which requires public and very open discussion of the science, data, analysis, and opinions.

Samantha Reiter, the Acting General Manager of LSGCD, notified The Golden Hammer two days ago that LSGCD has not asked its two primary scientific consultants, Bob Harden and Mike Thornhill, to execute Non-Disclosure Agreements. Reiter and LSGCD have been very helpful in providing information.

Reiter said two days ago,

“It has come to my attention that in recent articles you have referenced the LSGCD’s Confidentiality & Non-Disclosure Agreement, specifically with regards to how it pertains to the District’s Hydrologist and Hydrogeologist, Bob Harden and Mike Thornhill.  As you are likely aware, when responding to Texas Public Information Act requests, the responder is only required to produce documents responsive to the specific request, which is the practice the District follows.  On June 19, 2019, you submitted a Public Information Request to LSGCD.  In keeping with the law and practice of the District, I submitted the only document responsive to your request – the draft Confidentiality & Non-Disclosure Agreement template.  With regard to your request and mentions in your recent articles, the District does not have an executed Confidentiality & Non-Disclosure Agreement with the consultants on record.

“It is my hope that this will clarify any misunderstandings related to your Public Information Request and/or the Confidentiality & Non-Disclosure Agreement mentions in your articles.  The District also respectfully requests that you correct the mentions in your articles related to the Confidentiality & Non-Disclosure Agreements and the District’s consultants, Mike Thornhill and Bob Harden.”

Reiter has always been a readily accessible source of information and eagerly answered questions about subsidence. She, as LSGCD’s General Manager, made clear that LSGCD’s individual Board members, such as Vice President Harry Hardman, and most certainly LSGCD permittees, such as Sequeira and Stoecker, do not speak for the Groundwater Conservation District.

Reiter explained that “the District would like to reinforce the fact that GCDs [Groundwater Conservation Districts] are authorized to adopt groundwater regulations as practicable to control subsidence and that these regulations must balance conservation with meeting water needs while honoring private property rights, amongst other things, and use the best available science.  With regard to subsidence, the best available science includes work done by the USGS and LSGCD’s subsidence monitoring program, both of which indicate pumping in the Jasper does not cause subsidence in the same manner as groundwater pumping does in the Chicot and Evangeline.  As mentioned previously, land surface subsidence is known to occur in southeast Texas when groundwater pumping occurs in the Chicot and Evangeline aquifers.  These aquifer layers are not as thick and located at shallower depths compared to Fort Bend and Harris counties, thus providing a natural protection, of sorts, against subsidence in Montgomery County.  The USGS and the HGSD [Harris-Galveston Subsidence District, which is the GCD for those areas] have conducted over 40 years of research to identify the causes of subsidence and monitor the amounts of land surface subsidence.  LSGCD hopes to be able to add to that research with its own subsidence studies in the near future.”

Specifically, LSGCD has engaged Thornhill and Harden to study subsidence and to assist LSGCD in the adoption of appropriate groundwater regulations.

Reiter added, “Since the newly elected board took office, LSGCD has discussed the issue of subsidence in the Gulf Coast region, including Montgomery County.  Specifically, subsidence was discussed during the town hall meetings held in April, and LSGCD consultants addressed subsidence in March at the LSGCD and GMA 14 meetings and during the June 11, 2019 board meeting.  LSGCD, in conjunction with its technical consultants, provide the following answers to the questions posed.”

After this newspaper interviewed SJRA’s Houston on June 25, but without making his comments or data available to them, The Golden Hammer asked LSGCD, Hardman (who seems like a bit of a policy wonk!), Sequeira, and O’Sullivan to answer some questions.

Lone Star Groundwater Conservation District’s Samantha Reiter’s answers to questions about subsidence

Lone Star Groundwater Conservation District’s Acting General Manager Samantha Reiter.

1.  Should people care about subsidence?  Why or why not?

“Yes, subsidence can be very important in some areas such as the Gulf Coast region.  People who live in the lower lying coastal areas (i.e., lower elevations and flatter topography) have much more reason to be concerned with subsidence than those who reside further inland in areas of higher elevations with more topographic relief.

“Subsidence ranges in scale from local to regional.  Local subsidence may be the result of natural causes such as natural movement along growth faults or natural settling of the Gulf Coast aquifer system sediments.  Reportedly, some of the first drastic and localized subsidence observed within the Gulf Coast region was attributed to oil and gas field operations.  One other example of reported localized subsidence in the Gulf Coast region was due to dissolution of sulfur deposits associated with sulfur mining.  Similarly, dissolution of salt domes could cause localized subsidence.  Concerns with local subsidence could likely include infrastructure disruptions.  While movement of growth faults may also be caused by changes in artesian pressure in aquifers, subsidence due to groundwater pumping is generally a regional phenomenon.  One of the primary concerns of subsidence in the coastal regions is flooding due to storm surges associated with hurricanes.  Certainly, any changes to the slope or configuration of stream drainage characteristics can alter flow patterns – either lessening or increasing potential for flooding.

“Since the mid 1970’s, the USGS and the Harris-Galveston Subsidence District have conducted scientific investigations and subsidence monitoring for over 40 years. These efforts have identified and documented the susceptibility of land surface subsidence due to the production of groundwater in the Chicot and Evangeline aquifers.  The most concerning areas that have been identified are along coastal areas where permanent seawater inundation and periodic storm water surge can dramatically impact property.

“While up to ten feet or more of local subsidence has occurred near the Houston Ship Channel, the HGSD has successfully arrested any ongoing subsidence in these areas. In other areas of Harris, Fort Bend, Montgomery and Brazoria Counties subsidence has been detected through monitoring.  The greatest amount of subsidence, historically and projected to occur over the next 50 years, is within Harris and Fort Bend Counties.”

2. Is subsidence actually occurring in Montgomery County?  Do you know of any scientific explanation?  What is that explanation?

“Yes, subsidence is known to have occurred in the southern part of Montgomery County based on monitoring and long-term surveying of land surface.  As previously stated, land surface subsidence can occur from a variety of causes.  The main regional cause is due to groundwater pumping. See response to No. 4 for further information on groundwater production in connection with subsidence.

“Prior to 2001 there was neither measurement of compaction in geologic layers nor any direct measurement of land surface changing.  Therefore, estimates of subsidence within Montgomery County were based on comparing with past topographic maps, or were more likely simply extrapolated from the actual data collected at selected locations within Harris and Galveston counties.  The HGSD estimates that the maximum subsidence that had occurred in Montgomery County from 1906 to 2000 was slightly less than three (3) feet at the Harris-Montgomery county boundary slightly northwest of Humble; during the same time period the estimated subsidence at the Woodlands was slightly more than one (1) foot.  Again, prior to 2001, subsidence was estimated as opposed to being actually measured.

“Since 2001, LSGCD has obtained elevation measurements from several Port-A-Measure (PAM) sites that are a part of the HGSD network of sites across the region.  From 2001 to 2017, LSGCD and HGSD web sites show an additional 0.4 feet of subsidence just north of Humble, and about 0.8 feet west of Shenandoah.  During the period from 2012 to 2017 there is no definable trend at a PAM site near the dam at Lake Conroe or in southeast Conroe.  A different type of site known as a CORS site in northeastern Conroe indicates as much as 0.5 feet of subsidence from 2007 through 2017; however, this type of site is not as reliable as PAM sites, and some professionals dispute the validity of the data.  The USGS reports that the greatest rates of ongoing subsidence (during the period of 2013 to 2017) are still in northern and western Harris County.”

3.  Does subsidence cause flooding?  Why or why not?

“Well, in the simplest and most direct sense, no, only rainfall causes flooding.  When more intense and long duration rainfall events happen, then flooding occurs throughout Texas. Especially in urban areas, flooding is exacerbated by increases in impervious cover which limits infiltration and increases the amount of rainfall-runoff, and the impervious cover increases the flow velocities downstream, which reduce the concentration time of a watershed, and increase the total flow rate and hence flooding.  These effects are dramatic and much effort in storm water retention has occurred for over 30 years in site plans in many urban areas nationwide.

“Generally, subsidence could increase and/or decrease flooding because of the changes in slope that may occur regionally.  Areas that subside can cause greater drainage into these areas because of an increase in slope from upstream areas, but also retard greater drainage downstream because of an associated decrease in downstream slope.

“In most of Montgomery County, land surface elevations are much higher than downstream areas, so subsidence effects on flooding are believed to be less of a concern than in Harris County or other coastal areas.
Because of the complexity in effects of impervious cover, hydraulic detention and changes in drainage patterns, we know of no studies that have isolated the effects of subsidence on regional flooding.

“Flooding due to tidal surges in low-lying coastal areas has been documented, as subsidence exceeded 10 feet near the Houston Ship Channel.  As stated above, alterations of the characteristics of drainage basins can certainly change the patterns of flows.  There are no known studies linking flooding in Montgomery County to subsidence.  Flow characteristics of drainages and streams can be altered by development patterns including retention/detention ponds, runoff changes due to impervious cover, vegetation changes, etc.  These types of changes likely have more direct effect on flooding characteristics than subsidence in Montgomery County.”

4.  Does groundwater production cause subsidence? Why or why not?

“Groundwater production can cause compaction within the producing intervals that can result in land-surface subsidence.  And, as stated previously, subsidence caused by groundwater pumping tends to be regional in nature, as is evidenced by the subsidence maps often presented by the HGSD.

“According to USGS annual reports, all of the regional subsidence in the Houston area (including Montgomery County) is due to groundwater pumping from the Chicot and Evangeline aquifers.  Prior to pumping, the weight of overburden materials is ‘balanced’ with the matrix formed by the grains of sand and clay and the fluid pressures (i.e., artesian head) in the formation.  When the aquifer is pumped, artesian pressures are reduced.  Because of the pressure reduction, the weight of the overburden causes the layers of clay to compact and evacuate the water in the pore spaces.  Some of the compaction translates and is expressed as subsidence detectable at land surface.”

5.  Is there a “subsidence problem” in Montgomery County? If so, what is the solution?

“Subsidence monitoring indicates the rates of historical subsidence in southern Montgomery County are less than what has been experienced in many areas of Harris County.  Future projected subsidence in Montgomery County is less than projected to occur in areas of Harris and Fort Bend County.  The subsidence situation today in Montgomery County is very much the same as it was when LSGCD was formed, with generally less than one foot of additional subsidence since 2001.

“Fortunately, in Montgomery County the ‘geometry of geology’ provides a natural protection to limit subsidence in the Chicot and Evangeline aquifers when compared to other areas to the south.  These aquifers are thinner in total thickness and are shallower in Montgomery County and these are a limiting factor in the ability to economically reduce pressure and hence subsidence.

“Additionally, pumping in the Jasper aquifer is much larger in Montgomery County than in any other county in GMA 14.  The best available science provided by the State of Texas and the USGS, and monitoring data collected by LSGCD, both indicate land surface subsidence from pumping in the Jasper is not a concern like it is in the Chicot and Evangeline aquifers to the south.

“The beginning of the solution is to develop an accurate understanding of the history of subsidence and subsidence studies.  LSGCD is committed to address subsidence per the requirements of Chapter 36 of the Texas Water Code, which will include in-house studies.  In fact, LSGCD consultants have recently been authorized by the board of directors to develop a scope of work to study subsidence.  More importantly, however, subsidence is a regional issue.  Clearly, most of the subsidence in the region has been caused and is still caused by pumping in Harris County.  Therefore, the primary challenge in working toward a solution is the management of the common reservoir (i.e., groundwater reservoir or subdivision of a groundwater reservoir as defined in the Texas Water Code) in a manner that does not discriminate and allows for fair and impartial exercise of property rights.  The solution will certainly involve LSGCD working with the other districts and stakeholders in GMA 14.

“All of the groundwater districts and subsidence districts consider subsidence in their management plans. All of these regulatory agencies must balance the desires to minimize subsidence effects with meeting water supply demands while also honoring private property rights to use groundwater.  The solution necessarily involves a balancing of these concerns in accordance with science, law, and fulfilling the public interest of conservation and meeting the needs of the State of Texas for water supplies.”

Bill O’Sullivan The Sage’s answers to questions about subsidence

Left to right: Bill O’Sullivan The Sage, Montgomery County Republican Party Treasurer John Hill Wertz, and Montgomery County Eagle Forum Chair and Republican Precinct Chair Betty Anderson.

1. Should people care about subsidence? Why or why not?

“Maybe, if it’s a real problem.”
2. Is subsidence actually occurring in Montgomery County? Do you know of any scientific explanation? What is that explanation?
“Not an expert. I’ll defer to others.”
3. Does subsidence cause flooding? Why or why not?
“Flooding is caused by insufficient speed to handle runoff volume. It is more exacerbated by replacing water permeable acreage with hardscape causing greater runoff than absorption overwhelming the natural or man made structures to handle rain based on volume (Flood Control).”
4. Does groundwater production cause subsidence? Why or why not?
“Not an expert. I’ll defer to others.”
5. Is there a “subsidence problem” in Montgomery County? If so, what is the solution?
“Apparently less than an inch a year which should be readily manageable. The main problem is a scheme to monopolize the sale of groundwater through artificial forced restrictions on its usage, at the same time forcing the purchase of supplies of surface water from a single governmental source. This is more about creating that monopolistic practice than subsidence.”

RAW’s Simon Sequeira’s (also known as “Loco Ocho”) answers to questions about subsidence

Simon Sequeira, January 15, 2019. LSGCD Board member Jim Spigener watches with an approving glance.

1. Should people care about subsidence? Why or why not?

“Yes. It’s real and has the potential to cause property damage.
2. Is subsidence actually occurring in Montgomery County? Do you know of any scientific explanation? What is that explanation?
“Yes. But there is disagreement on why/who caused it and how much.  One theory says subsidence was caused by the large water users to the south before Montgomery County ever started pumping significant amounts of water.  Our southern counties didn’t just use water for municipal purposes, we farmed rice, and how do we farm rice? Once rice farming stopped in Harris and Fort Bend, and Harris and Galveston County converted to using surface water, subsidence seems to have been arrested.  Although not entirely. It’s important to note that even Harris and Fort Bend County subsidence districts allow for groundwater pumpage and predicted subsidence, because they need the groundwater.
3. Does subsidence cause flooding? Why or why not? 
“51” of rain in a 4 day period without proper drainage in one of the largest metropolitan ares in the US caused flooding.”
4. Does groundwater production cause subsidence? Why or why not?
“It depends on the soil and the aquifer.  Shallow aquifers with soils that are not compacted are susceptible to subsidence. Deep aquifers, like the Jasper where soils are compacted, are not susceptible to subsidence.”
5. Is there a “subsidence problem” in Montgomery County? If so, what is the solution?

“The question is-Is there subsidence in Montgomery County today and if so, is that subsidence caused by groundwater pumpage in Montgomery?  I believe there is some evidence of subsidence in south county that is likely caused by groundwater pumpage from the Evangeline aquifer.  And, because our aquifers stretch across county lines, at least some of that subsidence is caused by pumpage in Harris County.

“What are we going to do about it?
“Are we really prepared to condemn groundwater to stop subsidence?  Even if that would work, and it will not, what does that cost?  We would have to believe we value land over groundwater, both protected under the Fifth amendment as private property.  So, a government agency could ‘take’ the groundwater to ‘protect’ land.  But, the private property owner must be compensated.
“Gabe Collins, the Rice professor, did a study on the cost of water in Texas.  For our area, he came up with a price of $1,983.00/acre feet.  And we know we have 180 million acre feet of water.  For a whopping total of $356 Billion. Oh, and don’t forget, now we have to deliver water to every nook and cranny in Montgomery County, because we took their groundwater [through regulation]. Our water bills will soon be more than our mortgages.  The answer is deregulation and aquifer wide management, which affords all owners of groundwater their ‘fair share’ (not to be confused with equal share) and free markets for water to move based on capitalistic principles of supply and demand.”



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