Assessment of Variation in Austin Water Demands under Changing Climate Conditions

The Austin Water Utility (AWU) provides drinking water supply and wastewater disposal services to a population of more than 870,000 in Austin, Texas and several nearby communities. The AWU currently operates two water treatment plants with a combined production capacity of 1079 million liters per day (285 MGD) and 632 million liters (167 MG) of storage capacity. The utility also operates a wastewater collection and treatment system that consists of 4200 km (2600 miles) of sewers and two major advanced wastewater treatment facilities with a combined nominal capacity of 568 Ml/d (150 MGD). The utility's primary responsibilities include providing adequate water supply to meet both peak and long term average demands within its service area and to transport and treat wastewater generated in the area. While service population is a major determinant of these capacity requirements, the utility has noted a strong relationship among temperature, precipitation and water demand. As a result, long-term trends in climate means or variability could have a profound impact on the size and timing of planned capacity expansions and projected operating budgets and water conservation efforts. This paper identifies likely climate change scenarios and implications for the Austin area, some of which may already be underway.