Land use change, manufacturing, agriculture and a variety of other activities can have real impacts on water quality. The Texas Water Explorer examines several aspects of statewide water quality, including impaired waterbodies, streams and rivers at high risk of land use impacts, and areas where groundwater quality conditions may be worsening.
What does the Texas Water Explorer tell us about Water Quality?
Surface Water Quality Impairments
This indicator maps waterbodies listed as impaired waters by the state of Texas and summarizes patterns of impairment across Texas river basins.
Water Quality Impairments - Of the 30,000 kilometers of TCEQ-classified water quality assessment segments in Texas, 45% (13,600 kilometers) are considered impaired waters. The river basins with the highest prevalence of impaired streams are the Brazos-Colorado, Rio Grande, San Antonio and San Jacinto.
Vulnerability to Ecological Impacts From Land Uses
This indicator highlights areas where water quality is especially vulnerable to impacts from various land use methods. That danger is measured by the prevalence of different land use types in Texas watersheds and riparian areas.
Ecological Impacts From Land Uses - Of the 46,946 kilometers of Texas rivers and streams evaluated, 34% are at high vulnerability to ecological impacts from general land clearing, 18% from urbanization and 25% from row crop agriculture.
Groundwater Quality: Trends in Water Quality Parameters
Texas aquifers vary widely in water quality due to a variety of factors, including contamination in recharge zones and the consequences of oil and gas exploration and production. This indicator examines the trends in three water quality parameters in Texas aquifers over time.
Trends in Water Quality Parameters - 24 of Texas' 254 counties have experienced an overall increasing trend since 1988 in nitrate concentrations in at least one aquifer, eight have experienced increasing total dissolved solids and eight have experienced increasing chlorides.
The aquifers with the most increasing trends at the county-level for these 3 water quality parameters are the Ogallala, Carrizo-Wilcox, and Trinity.
The aquifers with the most counties with decreasing trends for these 3 water quality parameters are the Gulf Coast, Edwards-Trinity (Plateau), and Edwards.
Groundwater Exceedances of Drinking Water Quality Standards
This indicator measures water quality in Texas aquifers against drinking water standards to examine areas where groundwater quality issues may be of concern for humans and ecosystems.
Exceedances of Drinking Water Quality Standards - 135 of Texas' 254 counties had nitrate measurements from at least one aquifer in the last five years that exceeded drinking water standards; 126 counties saw the same measurement for total dissolved solids (TDS), 98 counties for chloride, 84 counties for sulfate, and 36 counties for fluoride.
When measuring for nitrates, TDS, chloride, sulfate and fluoride, the following aquifers had the most drinking water standard exceedances: Pecos Valley, Seymour, Ogallala and Edwards-Trinity (Plateau).