Climate change and global warming pose serious problems for sustainability of a sound human life. There have been many natural disasters such as floods, droughts, glacier collapses, typhoons, etc. Though many general circulation models have been developed and provided for worldwide hydrological and meteorological estimations, detailed causes and countermeasures on water-related disasters have not yet been
resolved. Climate change and global warming in a river basin involve many different components such as hydrological, hydraulic and water resources view points. Under these circumstances, water-related issues such as system dynamics, downscaling, river basin simulation and economic damage must be discussed to understand the impact evaluation linking it with human actions and the need for interdisciplinary collaborations.