Using large-scale climatic patterns for improving long lead time streamflow forecasts for Gunnison and San Juan River Basins

In a water-stressed region, such as the western United States, it is essential to have long lead times for streamflow forecasts used in reservoir operations and water resources management. Current water supply forecasts provide a 3-month to 6-month lead time, depending on the time of year. However, there is a growing demand from stakeholders to have forecasts that run lead times of 1year or more. In this study, a data-driven model, the support vector machine (SVM) based on the statistical learning theory, was used to predict annual streamflow volume with a 1-year lead time. Annual average oceanicatmospheric indices consisting of the Pacific decadal oscillation, North Atlantic oscillation (NAO), Atlantic multidecadal oscillation, El Nino southern oscillation (ENSO), and a new sea surface temperature (SST) data set for the Hondo' region for the period of 19062006 were used to generate annual streamflow volumes for multiple sites in the Gunnison River Basin and San Juan River Basin, both located in the Upper Colorado River Basin. Based on the performance measures, the model showed very good forecasts, and the forecasts were in good agreement with measured streamflow volumes. Inclusion of SST information from the Hondo region improved the model's forecasting ability; in addition, the combination of NAO and Hondo region SST data resulted in the best streamflow forecasts for a 1-year lead time. The results of the SVM model were found to be better than the feed-forward, back propagation artificial neural network and multiple linear regression. The results from this study have the potential of providing useful information for the planning and management of water resources within these basins. Copyright (c) 2012 John Wiley & Sons, Ltd.