River flow structure and its effect on pollutant distribution

Observations show that the space and time heterogeneity of river water composition persists over indefinite time even when the effect of pollutant sources and sinks is minor. The driving forces of such heterogeneity have been supposed and shown to be, among other factors, the stratification of water matrix. Studying the structure of water flow and its effect on pollutant distribution in water was based on a system of fundamental equations of the mechanics of a fluid with a free surface. It has been shown that such effect is due to the fine structure of flows, vortices, waves and highgradient interfaces (ligaments), which is formed and maintained by the motion of water masses. This conclusion extends our knowledge of the hydrological characteristics of water flow, enables one to better understand the nature of the heterogeneity of natural water composition, and it is of practical significance as such heterogeneity can be taken into account in making water management decisions.