Rangeland Ecohydrology, New Paradigm in Water Management of Arid and Semi-arid Lands

At the beginning of twenty-first century, the water crisis in the priority policy and management is inside and outside of the country as principle thoroughly human, social, economic and political rulers of the country is considered abundant. The World Bank has announced that during 1960 and 2025, water resources in Middle East, from 3430 m3 for the each person in year reach to 667 m3 because of population growth, degradation of natural resources, extent and spread of deserts. Study of ecohydrology in arid and semi arid rangelands of the world is one of the newest methods for available water resource management. In this science, all of effective ecology elements on water balance equation werereviewed. In these areas, a strong relation had been seen between ecology and hydrology processes. In these areas, not only lack of precipitation, but also irregular and unpredictabledistribution of precipitation was problematic. Ecohydrology pays particular attention to these areas of vegetation and its impact on groundwater and surface water.