Diffuse biogenic load from the catchment area of small watercourses

¹ Herzen State Pedagogical University of Russia, Geology and Geoecology Department, 198328 Saint Petersburg, Russian Federation
² Russian State Hydrometeorological University, Ecology and Bioresources Department, 195196 Saint Petersburg, Russian Federation

^* Corresponding author: nestem26@mail.ru

Abstract

The article systematizes information on quantitative parameters for assessing the modules of the background runoff of nutrients (total phosphorus and total nitrogen) with the catchment of rivers and lakes. A new approach proposed for estimating the modules of the background runoff of nutrients based on mathematical models. A methodology for calculating the modules of the background runoff of nutrients from the catchments of the rivers of the Baltic Sea basin developed. The study of the dependence of the trophic level of the water reservoir on the amount of phosphorus and nitrogen entering it led to the development of the so-called load concept, which is based on the idea of the existence of a quantitative relationship between the amount of phosphorus intake and the reaction of the reservoir. The maximum allowable export to the Gulf of Finland is 4860 t/year of total phosphorus and 106680 t/year of total nitrogen. These values significantly exceed the total load on the Novaya river from its catchment area: 0.072 t/year for total phosphorus and 0.066 t/year for total nitrogen.