Groundwater management zones for conjunctive water conservation in Hays County and the Hill Country region of Central Texas

This report examines a provision of Texas groundwater law granting authority to Groundwater Conservation Districts (GCDs) to create Groundwater Management Zones (GMZs) to address significant differences in hydrogeological conditions or groundwater use in specific areas of an aquifer. The report considers whether these management zones are effective tools for conserving groundwater in order to preserve surface water flows particularly in the Hays Trinity Groundwater Conservation District and, more generally, in the Hill Country region of Central Texas. It presents two case studies of existing GMZs in Barton Springs Edwards Aquifer Conservation District and Hill Country Underground Water Conservation District and insights from interviews with GCD staff involved in establishing and refining these zones. The report then evaluates how effective the zones would be for protecting the Middle Trinity Aquifer in the area around Jacob’s Well Spring and the Cypress Creek Watershed. It concludes by providing a road map and recommendations based on best practices drawn from the findings described above.