Ecohydrology is an interdisciplinary field studying the interactions between water and ecosystems taking place within the water bodies as rivers, lakes or towards land, in forests, desserts and other terrestrial ecosystems. This study is concerned with the effects of hydrological processes on the distribution, structure, and performance of ecosystems, and on the consequences of biotic processes on elements of the water cycle. The principles of Ecohydrology are expressed in three sequential components: Hydrological: The quantification of the hydrological cycle of a basin, should be a template for functional integration of hydrological and biological processes; Ecological: The integrated processes at river basin scale can be steered in such a way as to enhance the basin’s carrying capacity and its ecosystem services; Ecological engineering: The regulation of hydrological and ecological processes, based on an integrative system approach, is thus a new tool for Integrated Water Basin Management. The field of ecohydrology is providing new theoretical frameworks and methodological approaches for understanding the advanced interactions and feedbacks between vegetation and hydrologic flows at multiple scales. Areas of analysis in ecohydrology include: transpiration and plant water use, adaption of organisms to their water environment, influence of vegetation on stream flow and performace, and feedbacks between ecological processes and also the hydrological cycle. Ecohydrologists study both terrestrial and aquatic systems. In terrestrial ecosystems (such as forests, deserts, and savannas), the interactions among vegetation, the land surface, the vadose zone, and the groundwater are the main focus. In aquatic ecosystems (such as rivers, streams, lakes, and wetlands), emphasis is placed on how water chemistry, geomorphology, and hydrology affect their structure and function.