Atrium Lobby (Hyatt Regency Baltimore on the Inner Harbor)
Groundwater Conservation Districts (GCDs) are the preferred method of aquifer management in the state of Texas. Currently there are around 100 GCDs which are often defined along county lines. Therefore, several GCDs regulate the same aquifer and the policies of one may affect the groundwater availability in others. Texas also requires neighboring groundwater conservation districts to engage in joint planning activities and is divided into 16 Groundwater Management Areas (GMA). Each GMA is required to establish desired future conditions (DFC) for the aquifers under its purview. The DFCs are used to estimate the managed available groundwater (MAG) available for permitted use within the district. The idea of joint planning activities to develop consensus-oriented policies is indeed laudable, but the process must be managed properly. Decision makers within a GMA must be quickly able to evaluate the impacts of their potential policies in-order to determine acceptable outcomes. A combined simulation-optimization based Decision Support System (DSS) was developed to facilitate policy dialog in Groundwater Management Area 15 (which covers the Gulf Coast aquifer in South Texas). The simulation model was based on a calibrated MODFLOW-based regional groundwater flow model developed by the Texas Water Development Board. GCD-wide drawdowns and groundwater flux response functions were abstracted using constrained linear regression approaches and integrated into an optimization model. The DSS was used to evaluate different policy options such as the specification of a GMA wide drawdown constraint and identify the relative impacts of different districts within the GMA. The results of the study indicate that minimizing saltwater intrusion was a significant constraint for groundwater production in coastal districts and that a GMA wide average was not a major issue in the shallower Chicot formation but had an impact in the deeper Evangeline formation of the Gulf Coast Aquifer.
