Northern Portion of the Carrizo-Wilcox AquiferGroundwater Availability Model (GAM)This map shows the extent and location of the northern portion of the Carrizo-Wilcox Aquifer GAM.

In 2017, the Texas Water Development Board (TWDB) contracted with GSI Environmental, Inc. to update the groundwater availability model of the northern part of the Carrizo-Wilcox, Queen City, and Sparta aquifers in Texas. A final report and model will be released in early 2021.

GAM Update: Northern portion of the Carrizo-Wilcox Aquifer

Stakeholder Advisory Forums (SAF)

Send us an email if you would like to receive SAF notifications.

ID Date Location
SAF 1 5/9/2017 Nacogdoches, Texas
SAF 2 8/9/2018 Nacogdoches, Texas
SAF 3 8/27/2020 Online meeting


Current GAM: Northern portion of the Carrizo-Wilcox Aquifer

Model Files (2004, v. 2.01)

Please see the GAM files download page for a copy of the model files.

Model Grid

Model grid cells are geographically assigned to counties, groundwater conservation districts, river basins, groundwater management areas, and regional water planning areas within the model study area using a centroid based approach. The model grid is available in ESRI® shapefile format and comma-delimited text file.

Download northern model grid.

Aquifer Data

Aquifer data is only available as a package for the entire model area and requires GIS software for processing. Please see the GAM files download page for aquifer data.

Model Report (2003)

"Groundwater Availability Model for the Northern Part of the Carrizo-Wilcox Aquifer in Texas (2003)".

We are listing the 2003 report above as a resource on the conceptual analysis and data for the Carrizo-Wilcox Aquifer, an aspect that was not addressed by the 2004 GAM report.

Other Resources

Please see the Carrizo-Wilcox, Sparta, and Queen City aquifer pages for other reports and publications.

For model runs see the GMA 11 page.