Assessment of Possible Changes in the Nutrient Load onto Lake Onego under the Effect of Anthropogenic and Climatic Factors

• Published in: Water resources 2024-06, Vol.51 (3), p.241-251
• Main Authors: Kondrat’ev, S. A., Briukhanov, A. Yu, Shmakova, M. V., Rasulova, A. M., Galakhina, N. E., Zobkov, M. B., Vasilev, E. V., Oblomkova, N. S.
• Format: Article
• Language: English
• Subjects: Agricultural production; Anthropogenic factors; Aquaculture; Aquatic Pollution; Earth and Environmental Science; Earth Sciences; Ecological conditions; Environmental effects; Fish; Fish culture; Fish farms; Hydrobiology: Environmental Aspects; Hydrochemistry; Hydrogeology; Hydrology/Water Resources; Inflow; Lakes; Mathematical models; Nitrogen; Nutrient loading; Nutrient sources; Nutrients; Phosphorus; Runoff; Waste Water Technology; Water inflow; Water Management; Water Pollution Control; Watersheds
• ISSN: 0097-8078; 1608-344X
• DOI: 10.1134/S0097807824700751

Data on the main sources of nutrient load on Lake Onego watershed were collected along with the available data of field observations of nitrogen and phosphorus inflow into the lake. Mathematical modeling was used to assess the agricultural load onto the lake and its possible decrease due to the introduction of the best available techniques to agricultural production. It was shown that a decrease in agricultural load after the introduction of best available technologies is unlikely to have a significant effect on the ecological conditions of Lake Onego. Simulation calculations were carried out to evaluate an increase in the input of N and P into the lake from fish farms on the watershed under the condition that the rate of fish farming growth in the water bodies in the basin will remain the same up to the year of 2050. It is shown that, in this case, an increase in nutrient load onto the lake by 3.9% for P and by 1.9% for N relative to the current values can be expected. The most significant increase in nutrient export can be expected in Zaonezh’e: 11.2% for P and 10.6% for N. The possible changes in N and P input into the lake by the late XXI century due to changes in the runoff from the watershed is estimated under two RCP-scenarios—RCP 2.6 and RCP 8.5—the best and the worst in terms of their environmental effect. The actualization of scenario RCP 2.6 may lead to a decrease in the nutrient load all over the lake to 12.9% for N and 20.5% for P due to an increase in the flow. The actualization of the environmentally unfavorable scenario RCP 8.5 can be expected to cause an increase in runoff and an appropriate increase in the export of N from the entire watershed by 16.9% and P by 26.7%.