Geospatial Dataset for the Geologic Framework and Hydrostratigraphy of the Edwards and Trinity Aquifers Within Hays County, Texas, at 1:24,000 Scale

The karstic Edwards and Trinity aquifers are classified as major sources of water in south-central Texas by the Texas Water Development Board, and both are classified as major aquifers by the State of Texas. The Edwards and Trinity aquifers developed because of the original depositional history of the carbonate limestone and dolomite rocks that contain them, and the primary and secondary porosity, diagenesis, fracturing, and faulting that modified the porosity, permeability, and transmissivity of each aquifer and of the geologic units separating the aquifers. Previous studies such as those by the U.S. Geological Survey (USGS) and the Edwards Aquifer Authority (EAA) have mapped the geology, hydrostratigraphy, and structure in these areas at various scales. The purpose of this data release is to present the data that were collected and compiled to describe the geologic framework and hydrostratigraphy within Hays County, Texas in order to help water managers, water purveyors, and local residents better understand and manage water resources. The scope of the larger work and this accompanying data release is focused on the geologic framework and hydrostratigraphy of the outcrops and hydrostratigraphy of the rocks that contain the Edwards and Trinity aquifers within Hays County, Texas. These digital data are a revision to a previous publication of the geologic framework and hydrostratigraphy of the Edwards and Trinity aquifers that was completed in 2018 within Hays County, Texas. These digital data accompany USGS Scientific Investigations Map 3540 (Clark and others, 2025), which supersedes USGS Scientific Investigations Map 3418.