SIMULATION OF THE AUTUMN-WINTER RUNOFF OF THE ANADYR RIVER
Runoff during the autumn-winter low-water period is of great importance in the life of river ecosystems. In this work, the goal is to construct a mathematical model of the curves of daily water discharge during the autumn-winter low-water period (September-April) on the Anadyr River near the village Snezhny (catchment area 106 000 km2). Anadyr River is the largest waterway of the Chukotka. The river is used by public utilities, river transport in summer and road transport in winter. Pacific salmon spawn in this river every year. The conditions for the survival of salmon eggs in winter are influenced by the water content of the rivers. The basin under consideration is located in a zone of subarctic climate and continuous permafrost. Therefore, the autumn-winter low-water period on the Anadyr River lasts from September to April during this period, 4-6 % of the annual runoff occurs. Based on the average annual monthly water discharges for September-April, the averaged runoff depletion curve was calculated in relative ordinates, which is approximated by an exponential function. Based on this curve, you can predict daily water discharges from September 15th to April 15th of the following year. Verification calculations for the years of winters with different water content showed that the mathematical model works satisfactorily. Based on the data on the runoff of other hydrological stations in the Anadyr catchment, the study can be continued to derive a basin formula, which can be used to predict the daily water discharges of the autumn-winter low-water period on any unexplored river.