Brazos River Alluvium Aquiferinteractive map

Aquifer Facts

  • Aquifer type: unconfined
  • Area of aquifer: 1,057 square miles
  • Proportion of aquifer with groundwater conservation districts: 85 percent
  • Number of counties containing the aquifer: 13

Summary

The Brazos River Alluvium Aquifer is a minor aquifer found along the Brazos River in east-central Texas. The aquifer is as much as 7 miles in width and extends along 350 river miles from southern Bosque County to eastern Fort Bend County. Groundwater is contained in alluvial floodplain and terrace deposits, although the latter is not an appreciable source of water. The floodplain alluvium consists of fine to coarse sand, gravel, silt, and clay. These deposits have a complex geometry, with beds or lenses of sand and gravel that pinch out or grade vertically into finer material. In general, finer sediments occur in the upper part of the aquifer, and coarser material is in the lower part. The thickness of the aquifer ranges from negligible to 168 feet, with an overall average of about 50 feet. The water table generally slopes toward the Brazos River, this direction indicating that the river is a gaining stream in most places.

Recharge to the aquifer occurs from rainfall on the aquifer and subsequent downward leakage to the saturated zone. Discharge from the aquifer occurs through evapotranspiration, discharge to the river, and withdrawals from wells. Some wells can yield as much as 1,000 gallons per minute, but the majority of wells yield from 250 to 500 gallons per minute.

Water in the aquifer is very hard and fresh to slightly saline, generally containing less than 1,000 milligrams per liter of total dissolved solids but ranging to as much as 3,000 milligrams per liter in some wells. The aquifer is under water table conditions in most places and is used mainly for irrigation.

Reports

ID Date Type Description
Texas Aquifers Study 12/31/2016 Legislative Report Texas Aquifers Study: Groundwater Quantity, Quality, Flow, and Contributions to Surface Water
R-380 7/1/2011 TWDB numbered report Aquifers of Texas
R-365 2/1/2006 TWDB numbered report Aquifers of the Gulf Coast of Texas
B-6310 12/1/1973 Groundwater bulletin Reconnaissance Investigation of the Ground-Water Resources of the Brazos River Basin, Texas
R-186 9/1/1974 TWDB numbered report Ground-Water Resources of Grimes County, Texas
R-185 9/1/1974 TWDB numbered report Ground-Water Resources of Brazos and Burleson Counties, Texas
R-068 12/1/1967 TWDB numbered report Ground-Water Resources of Austin and Waller Counties, Texas
R-041 3/1/1967 TWDB numbered report Ground Water in the Flood-Plain Alluvium of the Brazos River, Whitney Dam to Vicinity of Richmond, Texas
GR05-005 3/31/2005 GAM run Post Oak Savannah GCD, water budget, water levels, drawdown through 2050, 2002 State Water Plan pumping summary, and interaction with the Brazos River Alluvium Aquifer
CR-1004831116 7/11/2012 Contract report Aquifer Test and Related Well Information from Public Water Supply Wells in Groundwater Management Area 8
CR-1004831114 8/9/2012 Contract report Ground Water Recharge Model: Calibration and Validation for Remotely-Sensed Dual Coefficient (RDC) GMA8 ET Estimation
GT13-031_TERS 1/15/2014 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 8
GT13-035_TERS_Ver2 5/16/2014 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 12
GT13-037_TERS 6/9/2014 GAM task - Total Estimated Recoverable Storage Total Estimated Recoverable Storage for aquifers in Groundwater Management Area 14
GR17-026_MP 3/17/2017 GAM run - Management Plan Management plan information for Middle Trinity GCD
GR17-020_MP 12/15/2017 GAM run - Management Plan Management plan information for Bluebonnet GCD
GR18-019_MP 7/6/2018 GAM run - Management Plan Management plan information for Brazos Valley GCD
GR18-021_MP 1/25/2019 GAM run - Management Plan Management plan information for Brazos Valley GCD
GR19-016_MP 10/24/2019 GAM run - Management Plan Management plan information for Southern Trinity GCD
GR21-006_MP 10/21/2021 GAM run - Management Plan Management plan information for Middle Trinity GCD
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