Influence of natural factors and human impact on water quality in the river Kudma – small tributary of the Cheboksary reservoir

Abstract

In this paper we present the results of water quality studies in the Kudma River – a small tributary of the Cheboksary reservoir (Middle Volga). The water quality of the river is formed under the influence of karst processes, widespread in its catchment area, as well as heavily polluted wastewater discharge from municipal sewer systems without nutrient removal facilities. Geological features of the catchment cause a significant increase in total dissolved solids and changes in the major ions content from the headwaters to the confluence with the Volga. At the same time, there is a rapid increase in the phosphorus and especially nitrogen content in the water below the places of domestic sewage release into the river. As a result, the Kudma River contributes to the nutrient pollution of the Cheboksary reservoir – one of the most eutrophic lakes in the Volga basin.