Freezing Types and Winter Runoff of Small Rivers

E. V. Gurevich

Investigations carried out in the Northern Dvina River basin revealed that the decrease in the ice thickness on small rivers is of significant importance in the increase in the water content of rivers in winter in recent decades. This process resulted in the improvement of the channel capacity as a result of the decrease in the ice formation intensity on the rivers and of the increase in the fraction of ground waters participating in the winter river runoff formation. It is proposed to consider the initial winter ice conditions as a separate important factor of this process as they define the types of river freezing influencing on the winter river runoff formation as well.