Water quality variation with storm runoff and evaporation in playa wetlands

Playas are the often most noticeable surface water feature in the Southern High Plains. The purpose of our study is to provide local and timely reference data on playa water quality and quantity in drier and wetter weather conditions. Water quality parameters of three playas in Texas, in the summer of 2016, were monitored via weekly environmental sampling. Annual water volume-depth dynamics within the study playas were also estimated by water balance informed by climate and geospatial data. The results showed that both direct rainfall and runoff affect the volume of water within the playa where the volume of runoff entering into a playa is contingent upon the surrounding drainage area. In addition, water quality does vary substantially from playa to playa (conductivity 180-850 μS/cm, TOC 13-81 mg/L) and between playa and non-playa surface water. Differences were related to local soils, drainage area size/slope, and land use. It was also found from the water quality analysis that playas are capable of containing a quality of water that would make them an attractive habitat for wildlife. The greatest economic value of playas may be their ability to contain high quantities of biodiversity though the future of their capacity to do so is uncertain.