A ROBUST COLOR PALATE: THE LATEST CHAPTER IN 20+ YEARS (AND COUNTING) OF BARTON SPRINGS EDWARDS AQUIFER TRACING (Invited Presentation)

The Barton Springs segment of the Edwards Aquifer is an important resource for the region. The aquifer feeds many springs, including Barton Springs: the jewel of Austin, which contributes up to 20% of the flow downstream in the Colorado River of central Texas, provides habitat for the endangered Barton Springs Salamander (Eurycea sosorum) and Austin Blind Salamander (Eurycea waterlooensis), and is a favorite swimming hole for a devoted following. The City of Austin, in cooperation with the Barton Springs Edwards Aquifer Conservation District and other partners, has been tracing the flow of groundwater in the Barton Springs Edwards Aquifer for over 20 years, which is a rich context for fine-tuning our understanding of aquifer behavior. The conditions within the aquifer are naturally dynamic and vary based on influences from precipitation, drought, well pumping, and land management. Robust models of the aquifer rely on groundwater traces that are repeatable and thoroughly characterize the flow-paths at various aquifer conditions. This latest chapter of groundwater tracing reaffirms faster connectivity at higher aquifer levels and validates a potential recharge enhancement project. Groundwater tracing is fundamental to understanding flow systems within karst limestone aquifers, and the data resulting from this study will help planners, managers, and scientists assess locations for proposed recharge enhancement, determine potential stormwater runoff impacts, predict the effects of hazardous spills and pollution, and evaluate other future projects.