Application of a SWAT Model for Hydrological Modeling in the Xixian Watershed, China

Water scarcity in Huaihe River, the sixth largest river in China, is stressed by the changing climate and intense human activities, especially in the headwater area. Xixian, situated in the upper reaches of the Huai River, is an important agricultural county with a population of more than one million people, and nearly one billion kg of crop yield every year. The projected climate changes and increasing population are expected to further complicate the utilization of already stressed water resources, endangering the agricultural activities in this area. There is pressing need for a watershed model to better understand the interaction between land use activities and hydrologic processes and to support sustainable water use. This study evaluated the performance of the Soil and Water Assessment Tool (SWAT) for hydrologic modeling in the Xixian basin; three methods of calibration and uncertainty analysis (sequential uncertainty fitting, generalized likelihood uncertainty estimation, and parameter solution) were compared and used to set up the model. The results showed that SWAT performs well in the Xixian River basin, that the hydrological water balance analysis of the basin indicated that base flow is an important aspect of the total discharge within the study area, and that more than 60% of the annual precipitation is lost through evapotranspiration. The calibrated model can be used to further analyze the effects of climate and land use changes and to investigate the effects of different cultivation styles and management scenarios on local water resources. (C) 2013 American Society of Civil Engineers.