1. Researcher, Water Resources Research Team, Korea Institute of Water and Environment, Korea Water Resources Corporation, 462-1 Jeonmin-dong, Youseong-gu, Daejeon 305-730, Korea.
2. Associate Professor, Dept. of Civil Engineering, Hanyang Univ., 17 Haengdang-dong, Seongdong-gu, Seoul 133-791, Korea (corresponding author).
3. Director General, Korea Institute of Water and Environment, Korea Water Resources Corporation, 462-1 Jeonmin-dong, Youseong-gu, Daejeon 305-730, Korea.