Assess the Impact of Climate Change on Water Resources in the Xi’an Heihe River Basin

Abstract

Climate change is a complex problem and becoming the leading challenge for humankind in the 21st century. Therefore, assessing climate change impacts on the social, economic activities and proposed solutions to respond to climate change is urgent and necessary. The Soil and Water Assessment Tool (SWAT) model provides an efficient way to assess complex water resources management problems of a watershed. In this research, we used the SWAT model to evaluate the impact of potential climate change on the availability of water resources in the Heihe River Basin, which supplies major drinking water to over three million people in Xi’an City, China. The response of the hydrologic system in this basin to climate change must be analyzed to provide a scientific foundation for planning future water managements, including groundwater diversions, dealing with adverse effects of more intensive floods and severe droughts, and reservoir water protection in the Heihe River Basin. To our knowledge, this is the first attempt to combine SWAT model with GCM outputs for urban water resources area in northwest China to assess the effects of climate change on river runoff. For this purpose, the SWAT model was first calibrated and then validated using the monthly streamflow data during the period of 2005~2009 and 2010~2013, respectively, from the Heihe River. Based on the calibrated model, the future water resources of the Heihe River Basin under the climate change scenario of the A1B from the IPCC report was simulated. The predicted annual runoff in the Heihe River Basin in the next 40 years (from 2020) shows an increase after a reduction, with the change in the average annual runoff ratio of -11.0%, -6.4%, 7.2%, and 190% for each of the next four consecutive decades. The average runoff during the flood season reaches a maximum in the 2050s, which may lead to serious challenges in flood control in the middle and lower reaches of the Heihe River region.