Аннотация:Kolyma is the main river of the East Siberian sea. Its length is 2129 km, the basin area is 643000 km2. However, the Kolyma River and its tributaries are the least studied explored rivers in Russia. The shortage of hydrological information increased in the 21st century, when the number of gauges in the Kolyma basin (measuring water flow) have decreased from 50 to 12. Gauges in the lower reaches and the mouth of the Kolyma, with measuring water discharges and turbidity, the suspended sediment load, were closed. In the Kolyma River Delta, water flow measurements are sporadic now and many years ago.
At the same time Almost simultaneously, since the mid-1990s, the hydrological regime of the Kolyma River and its tributaries began to change undergo significant changes due to increasing air temperature, mitigation of winter conditions, changes in precipitation regime, permafrost degradation, construction of the Kolymskoe and Ust-Srednekanskoe reservoirs, continuing large-scale mining. A notable increase in Kolyma water runoff (+14% in 1995-2015) is was one of the major results of these processes. It is important to note that this increase covers all rivers of the Laptev sea and the East Siberian sea. Their total water runoff has increased by 13%, the share of river inflow to the Arctic ocean coming from the territory of the Russian Federation has increased from 37.7 to 39.2%. A significant decrease of water turbidity of the Kolyma River downstream below the reservoirs (1.5-2 times) is was the second result, while the opposite trend is recorded on unregulated rivers of the Kolyma basin. Water temperature increase during the warm season, changes in the winter ice regime and of intensity of thermal abrasion of the banks is the third main result.
We record these and other large-scale changes due to a few stationary hydrological stations observations and data obtained by indirect methods. Therefore, a comprehensive and long-term Results of long hydrological expedition of Moscow University to the mouth of the Kolyma river in the summer of 2019, new hydrological materials and remote sensing data open up new prospects for studying these and other reactions of the Kolyma flow and regime to hydro-climatic and water management changes in the region , in search of their causes and effect connections. Some of these answers have been found and will be presented in the report.
The reported study was funded by RFBR according to the research project №18-05-60021