Subsidence, Close to Home
Recently Latitudes had the opportunity to attend a highly engaging presentation at the Texas Association of Environmental Professionals (TAEP) monthly meeting. TAEP is a valuable source for professionals in the environmental field. They also support prospective environmental professionals through networking and scholarships.
“The Past, Present and Future of Subsidence in the Houston Region”, presented by Michael Turco, the general manager of the Houston-Galveston and Fort Bend Subsidence District (HGSD). During his presentation, Mr. Turco defined subsidence as the lowering of the elevation or sinking of land surface caused by fluid withdrawal from the ground.
Subsidence in the Houston Area
More than 50 years ago, Houston became a textbook example of subsidence due to the cities’ rapid growth, natural lithology and groundwater extraction. Also, large fissures, or openings in the earth were occurring due to processes involved in oil/gas extraction. With all this movement underground, aquifers were impacted by changing elastic and inelastic hydrostatic pressures by the extraction of water from private wells or for municipal use.
Our “total water demand (TWD) is the percentage of groundwater areas rely on for everyday use”, some rapidly growing areas in NW Houston rely on roughly 40-50% groundwater. The results of relying heavily on groundwater vs surface water include: “Damage to infrastructure, faulting, wetlands loss and more frequent flooding” and can be seen throughout the Gulf Coast area.
Some steps to mitigate subsidence include: building more resilient infrastructure that secures reliable surface water sources as an alternative and the regulating of groundwater. NW Houston is currently on a plan to convert to surface water use, but within 20-30 years we could see 1-2 ft of subsidence.
Research projects on desalination techniques for brackish groundwater are in the initial stages of development. However, water conservation by the public and by private companies creates a positive impact on aquifer storage and recovery in the here and now.
Latitudes is a proud member of TAEP and grateful to be a part a hardworking, environmental community. Visit HGSD and SmarterAboutWater.org for more information about groundwater use and how to do your part for water conservation!