The vulnerability of water resources due to climate change and human activities is globally increasing. The phenomenon of hydrological change is complicated because of the combinations and interactions between natural climate fluctuation, global warming and human activities including changes in land utilization. The impact areas of hydrological changes are also not only within the basin, but reach to the ocean through coastal water exchanges. This book presents contributions focused on integrated water management from headwater to the ocean in a time of climate change and increasing population.