Hueco-Mesilla Bolson Aquiferinteractive map | cross-section

Summary

The Hueco-Mesilla Bolsons Aquifer, located east and west of the Franklin Mountains in Far West Texas, is recognized as a major aquifer in Texas. The aquifer is composed of basin-fill deposits of silt, sand, gravel, and clay in two basins, or bolsons: the Hueco Bolson, which has a maximum thickness of 9,000 feet, and the Mesilla Bolson, which has a maximum thickness of 2,000 feet. Although the Hueco and Mesilla bolsons share similar geology, very little water travels between them.

The upper portion of the Hueco Bolson contains fresh to slightly saline water, ranging from less than 1,000 to 3,000 milligrams per liter of total dissolved solids. The Mesilla Bolson also contains fresh to saline water, ranging from less than 1,000 to 10,000 or more milligrams per liter of total dissolved solids. Its salinity typically increases to the south and in the shallower parts of the aquifer. In both aquifers, water level declines have contributed to higher salinity.

The Hueco Bolson is the principal aquifer for the El Paso area and Ciudad Juarez in Mexico − nearly 90 percent of the water pumped from the Mesilla and the Hueco bolsons in Texas is used for public supply. Water levels have declined several hundred feet primarily owing to municipal pumping in the Hueco Bolson up to the late 1980s. Since that time, however, observation wells indicate that water levels have stabilized.

Reports