Ecological hydrology is a new scientific discipline that has arisen at the boundary of general hydrology and a great number of biological disciplines. The major guidelines of ecological hydrology are analysis of the interrelationships between the components of living and non-living nature and elaboration, on this basis, of norms of admissible depletion and pollution of water bodies. As elaborated, the norms must be made use of in water management systems wherein protection of water ecosystems is assigned the highest priority. In so doing, it should be noted that ecological significance of river ecosystems can vary greatly and, hence, approaches to specific water uses must also differ. From all the main components of ecosystem of the Earth (atmosphere, hydrosphere, lithosphere and biosphere) water resources are managed the most widely, but not always rationally and not without a damage living nature of water and near-water ecosystems.