1. Postdoctorate, China Three Gorges Cooperation, Beijing; formerly, Ph.D. Candidate, State Key Laboratory of Hydroscience and Engineering, Tsinghua Univ., Beijing 100084, China.
2. Ripley Professor, Dept. of Civil and Environmental Engineering, Cornell Univ., Ithaca, NY 14853.
3. Associate Professor, State Key Laboratory of Hydroscience and Engineering, Tsinghua Univ., Beijing 100084, China.
4. Professor, State Key Laboratory of Hydroscience and Engineering, Dept. of Hydraulic Engineering, Tsinghua Univ., Beijing 100084, China (corresponding author).