Montgomery County Commissioners Court to take no action regarding subsidence

A cross-section of the groundwater aquifers under Montgomery County. Source: United States Geological Survey.

The Golden Hammer Staff Reports

Conroe, April 28 – On Tuesday, April 27, 2021, the Montgomery County Commissioners Court addressed an agenda item on subsidence, the issue which has become a major controversy between Lone Star Groundwater Conservation District (LSGCD) and property rights advocates on the one hand and the San Jacinto River Authority (SJRA) which has attempted to scare citizens to purchase expensive surface water rather than groundwater.

SJRA has sought to advance the argument that groundwater water production is causing surface subsidence which results in more flooding. The problem with that argument, however, is that very little subsidence has occurred in Montgomery County, while most of the subsidence, which has occurred, likely has resulted from groundwater production in Harris County.

Surface water advocates were able to convince the Commissioners Court to place the following item on the agenda for the April 27 meeting: “Consider, discuss and take appropriate action on protecting Montgomery County’s aquifers and stemming subsidence.”

This newspaper has confirmed, through two confidential sources, one in the County Judge’s office and one in the County Attorney’s office, that Montgomery County Attorney B.D. Griffin advised the Commissioners Court during a secretive executive session yesterday that the County government has no legal authority whatsoever over subsidence or water production. Therefore, the Commissioners Court took no action, since LSGCD is the governing authority to address groundwater management issues.

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), shown immediately above, 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 last year:

“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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