1. Research Associate, Watershed Science and Environmental Ecology Research Institute, Wenzhou Medical College, University-town, Wenzhou, Zhejiang, P. R. China 325035.
2. Professor, School of Geography and Planning, Sun Yat-sen Univ., 135 Xingang Xi Rd., Guangzhou, Guangdong, P.R. China 510275 (corresponding author).
3. Engineer, Hydrological Bureau of Shantou in Guangdong Province, 40 Huangshan Rd., Shantou, Guangdong, P. R. China 515000.