1. School of Water and Environment, Chang'an University, Xi'an 710054, Shaanxi, China
2. Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of the Ministry of Education, Chang'an University, Xi'an 710054, Shaanxi, China
3. China University of Geoscience, Wuhan 430074, China
4. Key Laboratory for Environmental Pollution Prediction and Control, Gansu Province, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China