Response of Aquifers to Ground-Water Pumping Increases and Decreases in the Houston, Texas Metropolitan Area

The Houston metropolitan region has plentiful water supplies available from several ground-water aquifers and surface water reservoirs. Domestic, public supply, industrial and irrigation water wells are completed in fresh water sands in the Chicot and/or Evangeline aquifer or the deeper Jasper aquifer. Dams and reservoirs have been constructed to provide surface water supplies to the region.

The hydrologic response of the aquifers to moderate to large ground-water withdrawals is a reduction in the hydrostatic head in the aquifers and a decline in the static water level in wells. Large static water-level declines of about 130 to 300 feet were observed in some wells completed in the Chicot and Evangeline aquifers in east and southeast Harris County. Ground-water pumping also has resulted in the compaction of subsurface clays and land subsidence of approximately 1 foot to as much as 10 feet.

Regulations by the Harris-Galveston Subsidence District have reduced ground-water pumping in the east, southeast and central parts of the Houston metropolitan region. The hydrostatic heads in the aquifers have recovered in these same areas and the static water levels in some wells in the Chicot and Evangeline aquifers in east and southeast Harris County have risen about 160 to 230 feet. Ground-water reductions are required in the future in the north and west parts of the region and aquifer water levels will rise in response.

The major water users, regulatory entities and water planners should not fixate solely on developing and distributing surface water supplies to areas presently served only by water wells. Regulators may need to refine their ground-water usage restrictions as more ground-water pumping and aquifer response data are evaluated in the future. The ground-water aquifers are an essential resource that should be utilized sufficiently to help meet future water demands.