Lone Star Groundwater District confronts, demands apology from SJRA for misleading public re subsidence

Lone Star Groundwater District confronts, demands apology from SJRA for misleading public re subsidence

Image: Lone Star Groundwater Conservation District Director Jonathan Prykryl, who represents East Montgomery County on the Board, spoke emphatically to criticize the San Jacinto River Authority during the District’s Tuesday, February 9, 2021, meeting.

The Golden Hammer Staff Reports

Conroe, February 11 – The Lone Star Groundwater Conservation District’s (LSGCD) Board of Directors voted, after an intense discussion, to confront and demand an apology from the San Jacinto River Authority (SJRA), its General Manager, and its Board of Directors for repeated mis-statements about subsidence, its relationship to groundwater production, and the position of LSGCD on the issue.

Director Jon Bouche, who represents Commissioners Precinct 3, or south Montgomery County, said, “I’m sick of the propaganda.”

Jonathan Prykryl, who represents East Montgomery County, added, “It’s time for us to go on the offense…It’s a constant campaign of propaganda spewed out by the SJRA.”

Board President Harry Hardman was a bit more measured with his words. “There’s a lot of stakeholders involved. I think there are lot of well meaning people who have just been given the wrong information…There’s one state agency that is specifically guilty of that on a continual basis,” said Hardman, referring to SJRA.

The Board voted unanimously to direct LSGCD’s attorney to to develop a resolution that answers the unjust and untrue allegations against the LSGCD Board and demand an apology from SJRA General Manager Jace Houston, his Deputy General Manager, and the SJRA Board.

“They should be working with us to solve the problems,” Hardman said.

Larry Rogers, who represents the Woodlands Township, noted, “During the presentation tonight, there were 12 of 18 slides, which had corrections to what was said about the subsidence issue. People say we don’t care about subsidence.” In fact, LSGCD has commissioned an extensive geologic study on whether there is a relationship between groundwater production in Montgomery County and subsidence.

LSGCD General Counsel Stacy Reese said, “Lone Star is implementing the best available policy for our stakeholders…In October, 2017, the previous board, which included the SJRA’s General Manager, unanimously concluded that they should adopt a groundwater regulation that allows for measured aquifer declines. That study considered whether subsidence was an issue…That policy was backed by all of the stakeholders, which included SJRA and others we heard from [recently]…It was a huge change.” The previous board which adopted that policy, which ignored subsidence goals, included representatives from the SJRA, the Woodlands Joint Power Agency, and the City of Conroe, as well as other utilities.

Bouche noted, “The science hasn’t changed. The people haven’t changed, but the politics have changed, because the people who supported it are now opposed to it.”

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.

The basic subsidence argument proceeds as follows:

  • Removal of groundwater reduces the hydrostatic pressure of rock layers which have high porosity (spaces between the rock particles);
  • Reduction of the hydrostatic pressure results in more rapid compaction or diagenesis (low grade metamorphosis) of the rock strata;
  • The rocks respond with compression from the downward force of gravity;
  • The compression is horizontal movement, without lateral movement, thereby constituting subsidence;
  • With the ground levels lower, the risk of irregular drainage or even flooding increases.

The basic anti-subsidence argument proceeds as follows:

  • Removal of groundwater doesn’t reduce hydrostatic pressure in its practicality, because groundwater recharge equals or exceeds actual groundwater production;
  • There is not a one-to-one correspondence between groundwater removal and stratigraphic rock compression;
  • Compression may occur from non-human forces, such as normal rock compaction or diagenesis;
  • Montgomery County is far enough from the Gulf Coast that subsidence likely doesn’t occur;
  • Increases in flooding in Montgomery County arise from surface development and changes in weather patterns, as opposed to groundwater removal.

As Bouche noted, those interested in money, such as SJRA and its allies, seem to want to use whatever scare tactics they can muster to convince local residents they should purchase very expensive surface water from SJRA rather than obtaining their water from Montgomery County’s immense groundwater reserves.

In order to understand the science behind this issue, its important to understand what geologic features actually are beneath us.

A 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, President of LSGSCD, seems to agree with that conclusion and told The Golden Hammer in July of 2019:

“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.”

 

 

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