Finding new sources of water for semi-arid cities in unlikely places.

Determining alternative water sources to meet municipal water demands is important when availability is limited. The purpose of this study was to demonstrate a means for water planners to estimate the amount of combined sanitary wastewater and storm water that they might already be capturing through open air oxidation ponds. Increased understanding of the quantity of water that is already available could help water planners to better envision optimal water reuse scenarios. Using water and climate data on oxidation ponds in these three cities within the Texas Panhandle from 2010 to 2014, we evaluated water quantities which would be available for potential reuse. From the net monthly wastewater volumes values, the study also considered if per capita demand could have been met by reusing the wastewater. The study found wastewater volumes were lower in fall and winter months and much higher in spring and summer months. If a city considers reusing wastewater, blue water (groundwater) extraction could be reduced by as low as 45-50% in one city to as high as 100% in another. Water planners in similar environments and wastewater treatment systems may find this demonstration of potential reuse water quantity encouraging for better meeting their own water demands and enhancing water supply resiliency.

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.