Now there are many rives.Harmful influence on ecology of the rivers from dumps of industrial and agricultural waste. Thus plants, a fish perish, water becomes unsuitable even for bathing. Use of river water for cooling plants with the subsequent сливом in the river can raise the general temperature of water that strengthens negative influence of chemicals. If the rivers pass on territory of the several countries, as, for example, Danube or Rhine measures on protection of their ecology require the international cooperation in this area.