Edwards-Trinity (Plateau) and Pecos Valley AquifersOne Layer Groundwater Flow ModelThis map shows the extent and location of the Edwards-Trinity (Plateau) and Pecos Valley Aquifers One Layer Groundwater Flow Model.

The Texas Water Development Board improved the calibration of the Edwards-Trinity (Plateau) and Pecos Valley Aquifers GAM by converting the model from a two-layer to a one-layer model and by adjusting many of the input parameters including the model boundaries, model base and top elevations, recharge, hydraulic conductivity, anisotropy, and storage. The updated model was also calibrated for a longer period of time, 1930 through 2005, than the original model which was calibrated for the period 1980 through 2000. The updated model was constructed and run using a newer version of MODFLOW: MODFLOW-2000 versus MODFLOW-96 in the original model. Additionally, calibration was achieved using parameter estimation software, PEST, along with FORTRAN pre-processors.

Model Report

"Update of the Groundwater Availability Model for the Edwards-Trinity (Plateau) and Pecos Valley Aquifers of Texas." | erratum.

Model Files

Please see the GAM files download page for 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 model grid.

Other Resources

Please see the Edwards-Trinity (Plateau) and Pecos Valley aquifer pages and the Edwards-Trinity (Plateau) and Pecos Valley Aquifers GAM page for other reports and publications.

For model runs see the GMA 3, GMA 4, GMA 7, and GMA 9 pages.