1. Senior Engineer, Bureau of Hydrology, ChangJiang Water Resources Commission, Jiefang Ave. No. 1863, Wuhan 430010, China.
2. Professor, College of Hydrology and Water Resources, Hohai Univ., Nanjing 210098, China (corresponding author).
3. Professor of Engineering, Bureau of Hydrology, ChangJiang Water Resources Commission, Jiefang Ave. No. 1863, Wuhan 430010, China.