Are climate variations reducing the reliability of our water supplies

Abstract

Climate variability affects the availability and quality of water resources. Unanticipated extremes, such as unprecedented periods of drought, temperature, and intense rainfall / runoff, will affect water treatment and supply operations. Facilities have been designed and managed for a set of historical conditions that may well be changing. Utilities need to prepare themselves for additional uncertainties associated with a changing climate. Specifically, how might a changing climate affect the yield and reliability of existing and future water supplies? Since 1998, the southeastern United States have experienced record low stream flows and periods of drought extending over several years. Record low reservoir levels have been observed in municipal water supplies, while new and lower safe yields have been calculated. Is this a coincidence, or is a pattern emerging? Through the use of several examples in the Southeast, this paper will discuss the potential effects of climate variability on reliable water quantity, as well as possible water quality concerns. Comparisons of individual and system safe yield, before and after recent periods of drought (1998-2002, 2005, 2006-2008) will illustrate this issue.