1. a College of Urban Environment, Lanzhou City University, Lanzhou 730000, Gansu, China
2. b State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi an University of Technology, Xi an 710048, Shangxi, China
3. c Bureau of Civil Affairs of the Lanzhou City, Lanzhou 730000, Gansu, China
4. d College of Water Conservancy and Hydropower Engneering, Gansu Agricultural University, Lanzhou 730000, Gansu, China