Assessment of nutrient load on the Cheboksary Reservoir using the results of modeling runoff and removal of biogenic elements from the pilot catchments

Abstract

The paper presents the results of an approximate assessment of the nutrient load on the Cheboksary reservoir of the Volga Cascade from the right-bank and left-bank parts of the catchment basin. The main solution tools are the recognition of the underlying surfaces in the catchment and mathematical modeling. The catchment basins of the Kudma (right-bank tributary) and Linda (left-bank tributary) rivers have been identified as pilot sites. The catchment basins of the Kudma (right-bank tributary) and Linda (left-bank tributary) rivers have been identified as pilot sites. The representativeness of the selected pilot sites for the catchment basins of the Cheboksary reservoir is demonstrated. The mathematical basis of the research was the “precipitation-runoff-removal” model describing the formation of runoff and removal of biogenic elements from the catchment basin. To calibrate the mathematical model, the materials of observations of water discharges and the content of chemical agents in the gauging sections of the pilot catchment basins were used. The modeling data provides an approximate estimate of the total nutrient load on the Cheboksary reservoir, as well as the contribution of natural nitrogen and phosphorus removal to the load from the catchment basin.