Duration and Frequency of Ponded Water on Arid Southwestern Playas

Abstract : Playas, "The flat-floored bottom of an undrained desert basin that becomes at times a shallow lake which on evaporation may leave a deposit of salt or gypsum,"1 are regulated by the U.S. Army Corps of Engineers (Corps) under the provisions of the Code of Federal Regulations 33 CFR 328.3 A implementing Section 404 of the Clean Water Act (CWA). The Corps and others perform jurisdictional delineations of playas to determine whether certain areas are subject to Section 404 regulations. However, delineating playas has been found to be problematic (e.g., Doug and Colberg 1996; Lichvar and Sprecher 1996; Brostoff, Lichvar, and Sprecher 2001). Case studies have been performed for several playas in the western Mojave Desert, California, to examine surface hydrology. The purpose of this study was to estimate the duration and frequency of inundation at these playas.