Палеогидрология рек бассейна реки Дон

The hydrological regime of large meandering rivers that existed in the Don River basin 18-14 thousand years ago was reconstructed using paleochannel hydraulic geometry, in particular, bankfull width. For paleohydrological reconstructions, the method of regime equations was used. The relationship between the channel bankfull width and the average maximum discharge is derived from the data on the modern channels. This equation is applied for calculating the maximum discharges of the paleorivers using bankfull width of paleochannels. Then, relationships are constructed between the calculated maximum paleodischarges and catchment areas for the territories within the Don River basin with homogeneous paleolandscapes. On this basis, specific discharges are calculated for elementary catchments. They do not depend on the catchment area and therefore can be mapped. The reconstructed maximum daily specific discharges during the snowthaw period were up to 120 mm/day in the north of the Don basin, in the periglacial forest steppe, and 20–30 mm/day in the central part of the basin, in the periglacial steppe. The average daily maximum runoff depth for the basin was about 50 mm, which is more than six times higher than the current value. The annual river runoff was calculated from the ratio of the average flood and the average maximum runoff depth using a simplified snowthaw model, taking into account air temperatures within the modern region-analogues. The total annual runoff from the territory of the Don basin was about 113 km³, which is four times the modern runoff from the same basin. From these estimates of the annual and especially maximum discharges, it follows that there was abundant winter precipitation with short and rapid snowmelt during the formation of large paleochannels.