Diagnosis of The State and Changes in The Ecosystem of Lake Onego and Watershed Based on The Information-Analytical System

Abstract

The results of the diagnosis of the state and changes in the ecosystem of Onegskoe Lake (Lake Onego) and the watershed are presented using the developed information and analytical system “Lake Onego-watershed” (IAS), consisting of a comprehensive database (DB), a combined database of Roshydromet and Northern water problems institute/Karelian Research Center of the Russian Academy of Sciences on the nutrient load for the modern period 1995–2022, the ILLM mathematical model for assessing the removal of nutrients from the watershed and the formation of the nutrient load on the lake and the 3D-mathematical model SPLEM, developed for Lake Onego. Information was collected on the main sources of nutrient load in the Lake Onego catchment area, as well as available field observation data on the flow of nitrogen and phosphorus into the lake. The contribution of different nutrient sources coming from river runoff, diffuse sources, urban discharges and from trout farms was calculated for the lake and the main limnic areas. Based on data from field observations over the past 30 years and the results of numerical experiments using the SPLEM model with a grid resolution of 1 km it is shown that the ecosystem of the lake not only did not restored after the reduction in anthropogenic load after 1991, but eutrophication of waters in the lips and bays continues due to the influence of industrial and agricultural enterprises, trout farms and noticeable climate warming. Functional for the IAS “Lake Onego-catchment” to visualize the main modeling results on a 1 km grid was developed, and a web application interface has been created.