1. Institute for Environmental Systems Research, Osnabrück University, Barbarastraße 12, 49076 Osnabrück, Germany
2. Water Resources Research Center, Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
3. Kajima Technical Research Institute Tobitakyu 2-19-1, Chofu 182-0036, Japan