Forms, quantities, and variability of organic substance inflow into the Rybinsk Reservoir

The data on the content of total and some forms (suspended, labile, and carbohydrate-like) of organic substances in inflowing rivers of the Rybinsk Reservoir are presented. The greater portion of organic substances enters the Rybinsk Reservoir in the form of difficulty decomposable dissolved compounds. The labile fraction accounts for no more than 4.6% of the total amount. The distribution of the total organic substance runoff within a year correlates with the water runoff volume. The quantity of organic substance inflow with each river depends both on the water runoff volume and on the value of mean weighted concentrations of organic substances in water of these rivers. It is suggested that the obtained values should be considered as regional geochemical constants, which may be useful in preparing the total balance.