In many parts of the world, the adverse effects of long-term, often unreasonable, human activities have now been discovered. This concerns both the direct use of water resources and the surface transformations that have occurred in many river basins. To a large extent this is due to the dramatic increase in global water withdrawal since the 1950s. In turn, this increase was caused by the scientific and technological revolution which allowed the intense development of production capabilities in all spheres of the world economy. Compared to previous decades, the annual withdrawal of water in the period 19.51-60 quadrupled. This has occurred due to the dramatic expansion of irrigated areas, the growth of water consumption in industry and thermal and energy engineering, and the intensive construction of reservoirs on all continents. Throughout the world, over the last 25-30 years, a massive anthropogenic change has occurred in the hydrological cycle of rivers and lakes, which has influenced the quality of waters, their potential as water resources and the global water balance. The extent of water resources, their spatial and temporal distribution, are determined not only, as in the past, by natural climatic variations, but today also by human economic activities. In many parts of the world, water resources have become so depleted and contaminated that they are no longer able to meet the ever-increasing demand for them. This has become the main factor hindering economic development and population