This article analyzes the dynamics of pollution of water bodies (on the example of the Don river basin) by stationary sources for the period 2000-2015. using the methods of mathematical statistics, an empirical model is constructed to study the trend and fluctuations of pollution dynamics. For this purpose data of rosvodresurs of the Russian statistical Yearbook are used. The adequacy of the model for three-year forecasts with an error of up to 8% was checked. A system of differential equations describing the pollution process is derived.

Keywords: mathematical model, statistical methods, trend lines, differential equations, prediction, model adequacy, the forecast error, the dynamics of pollution, water resources, waste water