Model-Based Assessment of Nutrient Load into Water Bodies from Different Landscape Types

The overall aim of the work is the assessment of the current level of the external nitrogen and phosphorus load and its individual components at the Kuibyshev Reservoir of the Volga Cascade using the information on the landscape structure of the catchment area. A mathematical model of the average annual export of total nitrogen and phosphorus from river catchments with heterogeneous structure was developed, using the results of remote assessment of the landscape structure of the underlying surface. The nutrient load was calculated both for agricultural areas, and for areas that are not currently in agricultural use. The model is calibrated according to the state monitoring data at the pilot sites, which are the watersheds of the Kazanka River (left-bank tributary) and Sviyaga (right-bank tributary). An approximate assessment of the nutrient load on the Kuibyshev Reservoir, formed at the left-bank and right-bank parts of the catchment is presented, taking into account the background (natural) and diffuse (anthropogenic) components of the load.