Dockum AquiferAlternative Groundwater Flow ModelThis map shows the extent and location of the Dockum Aquifer GAM.

The original groundwater availability model for the Dockum Aquifer was found to be ineffective for use in predictive simulations. This original model for the Dockum Aquifer could not appropriately perform predictive simulations because it 1) used a layer to represent units overlying the Dockum Aquifer that was controlled by general-head boundary conditions, which inhibited translation of inactive cells in the models representing the overlying units to the Dockum Aquifer model, and 2) contained discrepancies in the layer elevations between the Dockum Aquifer model and the models representing the overlying units, which made using head elevations in predictive simulations a challenge.

The changes made include removal of the overlying layer representing younger units, transfer of the general-head boundary conditions directly to the top of the Dockum Aquifer cells, use of historical saturated thickness from the northern and southern Ogallala Aquifer groundwater availability models (as opposed to water-level elevation), shortening the historical period of the model to only the calibration period, and recalibration of the model using a parameter estimation procedure (PEST) and trial-and-error.

Model Files

Please contact David Thorkildsen (512-936-0871) for a copy of model files. The model files are available in an electronic format with a small processing fee per CD/DVD.

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 Dockum Aquifer and Dockum Aquifer GAM pages for other reports and publications.

For model runs see the GMA 1, GMA 2, GMA 3, GMA 6, and GMA 7 pages.