USING FREQUENCY CURVES OF HYDROCHEMICAL INDICES FOR ESTIMATION OF WATER QUALITY OF THE NORTHERN DVINA RIVER

摘要

Analysis is conducted of long-term data on the organic matter content in the Northern Dvina River and its tributaries by using exceedance probability curves of hydrochemical characteristics. Disadvantages of the current approach to estimating water quality from organic matter content are shown. The method neglects the background values and seasonal variations of hydrochemical indices.