Boundary Changes and Additions to the Aquifers of Texas

The Texas Water Development Board (TWDB) periodically updates the maps of Texas' aquifers to add newly recognized aquifers or to update aquifer boundaries. For the 2007 State Water Plan TWDB adjusted the boundaries of several of the state's aquifers, including the Blaine, Bone Spring-Victorio Peak, Edwards (Balcones Fault Zone), Igneous, Lipan, Ogallala, Pecos Valley, Seymour, and Trinity aquifers. These changes were made based on groundwater availability modeling (GAM) studies, other scientific studies, and comments from the public supported by existing information. Similar changes are possible for the 2012 State Water Plan, based in part on new work being done on brackish water resources in the state. These include increasing the size of the Dockum Aquifer to match the extent of Dockum Group rocks, refining the subsurface extent of the Marble Falls Aquifer, and refining the boundary of Yequa-Jackson Aquifer based on a recent GAM study. It is possible that new aquifers will be added to the current list, including the Colorado River Alluvium and the Austin Chalk. Another recent GAM study in the area of the Llano Uplift may improve the definition of boundaries of aquifers in that area.