By Katrina Grantz, Balaji Rajagopalan, Edith Zagona, and Martyn Clark. Published in the Journal of Water Resources Planning and Management, 2007.
Abstract: Water managers in the western United States and throughout the world are facing the increasing challenge of supplying a variety of water demands under the growing stresses of climate variability and of population and economic growth. Accurate streamflow forecasts are key to the water resources planning and decision-making process. There is growing evidence that variability in western streamflow is modulated by large-scale ocean-atmospheric features. Traditional forecasting techniques, however, do not systematically utilize large-scale climate information. In this study we present a framework for incorporating climate information into water resources decision-making and demonstrate the method on the semiarid Truckee-Carson Basin in Nevada where environmental, agricultural, and municipal demands compete for a limited supply of water. In this basin, water managers must plan carefully to meet the demands of timing and required flowrates. The framework presented in this paper consists of a streamflow forecast system that is based on large-scale climate information. The forecasts are then incorporated in a decision-support tool to aid in water resources planning and decision making. Previous work on the Truckee-Carson Basin has demonstrated that incorporating climate information into the forecast can increase the accuracy (or skill) and lead time of forecasts. This paper focuses on the decision-support system that is used to evaluate decision strategies and demonstrates possible water management improvements. The performance of the framework and the improved forecasts are evaluated on the Truckee-Carson system by using a suite of years from the historical record.