Challenge: To develop a robust groundwater model, that accurately accounts for the highly variable hydrogeologic characteristics of the Cross Timbers Aquifer and provides state and regional water planners with an effective tool for managing this groundwater resource.
Solution: The Cross Timbers Aquifer extends over 17,800 square miles over 33 counties in north-central Texas, where it provides a small but important source of water in the region, particularly in the far northwest portion of the aquifer area where rapid population growth results in increasing water demand. INTERA’s key efforts included refining several elements of the conceptual model (previously developed by another consultant) to improve its representation in a numerical framework, including extension of the model domain, layering structure, historical groundwater use estimates, and recharge estimates. We built the model using MODFLOW 6 along with a fully scripted workflow that allows for efficient and repeatable updates. The model was calibrated using the PESTPP-IES (Iterative Ensemble Smoother) routine, an advanced parameter estimation method. We also conducted sensitivity analysis to evaluate how key model parameters influence simulated groundwater levels, baseflows, and overall model performance.
Results: INTERA delivered a robust and comprehensive tool for regional planning and long-term water budget evaluations. The model not only captures the large-scale dynamics of groundwater movement but also accounts for key uncertainties. It serves as a living tool that both informs future data collection efforts and that can be improved as new data are collected. Read the full report here: Cross Timbers Aquifer Groundwater Availability Model | Texas Water Development Board
