Wednesday, February 08, 2017Register
 Edwards Spatial Data

Choose from the spatial layer files below for download. The data include Edwards water quality, threatened and endangered species critical habitat, and sampling station and gauge locations. All data available for download were used in the creation of the spatial data for the Edwards Aquifer portal. The files are available for download as easy-to-use ESRI layer packages, compatible with ArcGIS 9.3.1.

After downloading, double-click the file and specify an output location to unpack the files. The data will then be added, fully symbolized, to ArcMap. For more information about layer packages, click here. Please contact Stephanie Glenn at for information about obtaining GIS data compatible with older versions of ArcGIS or questions about the data.

Groundwater Quality Data
Source: Texas Water Development Board

Total Dissolved Solids

Groundwater Quantity Data
Source: Texas Water Development Board

Approx. Depth to Water Table: 1981-1990
Approx. Depth to Water Table: 1991-1995
Approx. Depth to Water Table: 1996-2000
Approx. Depth to Water Table: 2001-2005

Linked Well and Gauge Locations
Source: Texas Water Development Board and National Weather Service

TWDB Selected Wells
NWS Selected Gauges

Expanded Precipitation Gauge Locations
Source: National Weather Service

NWS Expanded Gauges

Average Precipitation 1971-2000
Source: Oregon State's PRISM Climate Group

Edwards Annual Average Precipitation: 1971-2000

Surface Water Monitoring Stations
Source: Texas Commission on Environmental Quality and U.S. Geological Survey

TCEQ Selected Stations
USGS Selected Stations

Endangered Species Federally Designated Critical Habitat
Source: US Fish and Wildlife Service

Comal Springs Dryopid Beetle
Comal Springs Riffle Beetle
Fountain Darter
Peck's Cave Amphipod
San Marcos Gambusia
San Marcos Salamander

Endangered Species Presence Previously Reported
Source: Literature Review

Barton Springs Salamander
Blanco Blind Salamander
Cascade Caverns Salamander
Comal Blind Salamander
Texas Blind Salamander
Toothless Blind Catfish
Widemouth Blind Catfish

 Edwards Aquifer

The Major Aquifers in Texas; map created by the Houston Advanced Research Center.

The Major Aquifers in Texas; map created by the Houston Advanced Research Center.

The Edwards Aquifer covers about 4530 square miles in parts of 11 counties in Texas. Edwards is the focus of this study due to its unique physical nature as a karst aquifer resulting in highly sensitive environmental areas that provide habitat to fourteen different threatened and endangered species. Water from the aquifer is used for municipal, irrigation and recreational purposes; 54% of this amount is for municipal purposes.

The Edwards Aquifer is comprised mainly of limestone; over time as groundwater has moved through the system, erosion of the limestone has caused a great deal of porous zones, leading to the cavernous nature of the aquifer. These caves and natural springs honeycombed throughout the aquifer provided small habitats that are ecologically unique. Due to being specialized niches, they are also extremely vulnerable to changes in groundwater or surface water conditions. The high permeability in Edwards Aquifer means it responds quite quickly to changes in precipitation; during times of below average rainfall or drought, conditions in the springs or caverns can quickly be reduced to environmentally detrimental levels. The following pages discuss the variety of threatened and endangered species in the aquifer, and highlight changes in precipitation and surface water and groundwater quality and quantity in the Edwards Aquifer. The data can be viewed in the Edwards Aquifer Mapping Application.

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