Playa Water Quality Changes with Time and Effects on Clarification

Abstract

An estimated 2 to 5 million acre-feet of runoff water accumulates annually in playas on the semiarid southern high plains; however, development of this large potential water source has been impeded by lack of water quality data. Most of the water is lost by evaporation, and timely utilization is essential. Therefore, a particular need exists for quality data on freshly impounded water. Water from five playas was sampled and analyzed at intervals for 24 days following runoff from a single storm. Chemical analyses showed playa waters were excellent for irrigation; however, adequate economical clarification is probably needed for such projects as direct aquifer injection. With aging, less synthetic cationic polyelectrolyte and more alum was required for water clarification. Initially low nitrate and chemical oxygen demand values decreased with time.