RESPONSE OF WATER QUALITY IN SAN SOLOMON SPRINGS TO MESOSCALE PRECIPITATION EVENTS: IMPLICATIONS FOR GROUNDWATER SUSTAINABILITY AND HEALTH OF AQUATIC ECOSYSTEMS IN TRANS-PECOS, TX, USA

The San Solomon Springs complex discharges from a fracture-controlled regional groundwater system in Trans-Pecos, Texas, US, and provides aquatic habitats for multiple endemic and federally-protected species. Climate change, drought, and development of groundwater resources for use by the agricultural and energy sectors (including unconventional resource recovery in the Delaware basin) pose potential risks to the long-term sustainability of the spring complex and the associated groundwater-dependent ecosystem. Regional springs in arid settings globally can be vulnerable to declines in flow as a result of groundwater extraction; additionally, negative impacts on aquatic habitats can result from desiccation, increases in temperature, and elevated salinity associated with drought effects on springs. To address these challenges for San Solomon Springs, an understanding of the local and regional components of groundwater flow to the springs must be developed. This study combines in-situ long-term monitoring of water quality parameters (2011-2012) with aggregate Nexrad reflectivity and regional precipitation to examine the local and intermediate components of groundwater flow. We document a correlation between mesoscale precipitation events (convective storms) and subsequent dips in specific conductance and spikes in turbidity of water discharging to San Solomon Springs. The lag between storm event and spring response averaged ~35-45 days for the 26 captured events and was noticeably influenced by storm magnitude. The combination of in-situ monitoring with analysis of meteorological conditions have enabled quantification of spring response to local events and, for the first time, examine in more detail the spatial component of the local and intermediate flow systems. These insights are critical for spring protection because they elucidate where spring discharge may be more at risk of dewatering or contamination.