Groundwater is water found beneath the Earth’s surface that gradually seeped down by saturating soil or rock. This water is stored in underground crevices and in the pores of rocks and other materials beneath the surface.

A water well is an artificial hole dug to access groundwater from aquifers.

Subsidence is a drop in the surface level of land.  It sometimes occurs when groundwater is pumped from an aquifer. During this virtually irreversible process, cracks, fissures and sink holes can appear in the ground. 

The southern area of the Brazos River basin has experienced a great deal of subsidence.  To combat this problem, regulatory bodies known as subsidence districts were created by the State of Texas to begin lowering the use of groundwater and moving to a larger use of surface water in order to reduce groundwater pumpage and thereby slow the subsidence of the terrain near the Gulf of Mexico.

In addition, the legislature added language to the Texas Water Code explicitly recognizing groundwater conservation districts as the “preferred method of determining, controlling, and managing groundwater resources”(§36.0015)   By statute, the purpose of groundwater districts is to “provide for the conservation, preservation, protection, recharging, and prevention of waste of groundwater, and of groundwater reservoirs or their subdivisions, and to control subsidence caused by withdrawals of water from those groundwater resources or their subdivision …” (Texas Water Code §36.0015)

The photo at the left illustrates subsidence in the area thought to have experienced the worst amount of subsidence in the United States.  The signs posted on the telephone pole illustrate the altitude measurements for that location as it experienced subsidence.  (photo courtesy of the USGS.)

 Groundwater districts are organizations created by legislation or through the petition process to provide administration over the use of water pumped from a specific area.  These districts have limited power, primarily in the spacing of wells, education and planning, prohibiting waste and permitting well drilling.

For more information on groundwater conservation districts, please see the Texas Water Development Board here.  The Texas Commission on Environmental Quality has a myriad of information on groundwater supplies in Texas.  You may access their site by clicking here. 

The Texas Alliance of Groundwater Districts (TAGD) is an organization of underground water conservation districts of Texas formed to further the purpose of groundwater conservation and protection activities.  To learn more about this organization, click here. 

The Texas Groundwater Protection Committee is made up of numerous state agencies working together to bridge the gap between groundwater programs and improve the coordination between the member agencies to protect groundwater.  To learn more about this organization and to view their educational website, click here.  

For a current map of groundwater districts, click here. 

 A spring is a place where groundwater flows naturally from the Earth’s surface.

A confined aquifer has layers of impermeable material situated above and below that create pressure within the trapped water. When a well permeates such an aquifer, this pressure causes the water to rise above the top of the aquifer. When an aquifer is unconfined, it rises and falls with atmospheric pressure.

photo courtesy of USGS

There are 14 sub-watersheds within the basin, including the Caprock, Salt and Double Mountain Forks, Clear Fork,  and the Upper, Central and Lower watersheds. The Bosque, Leon, Lampasas, Navasota and Little rivers as well as Aquilla, Yegua and Upper Oyster creeks also have sub watersheds in the basin.  For a full size map, click here. 

Texas groundwater has long been governed by the “rule of capture” doctrine, generally meaning if you can capture it from beneath your property it is yours, regardless of impacts beyond your property. However, in the late 1940s, the Texas Legislature passed a law that allowed for the creation of groundwater conservation districts. These entities have limited power over groundwater, primarily in the spacing of wells, education and  planning, prohibiting waste and permitting well drilling.

Conjunctive use is the coordinated management of surface water and groundwater supplies to maximize the yield of water resource.

An aquifer is an underground geological formation that stores and transmits water in amounts that can be extracted by a water well in useful quantities. For a full size map, click here.