Application of satellite data for monitoring eutrophication in glacial lakes of Rila mountain, Bulgaria

The following study presents results of the application of satellite optical data for eutrophication monitoring in glacial lakes located in the highest mountain in Balkans-Rila mountain. The group of the Seven Rila lakes and its second lake called Ribnoto was used as a test area in the presented research. Several differential water and vegetation indices including Normalized Differential Water Index (NDWI), Normalized Differential Vegetation Index (NDVI) and Tasseled Cap Transformation for segmentation of Sentinel-2 data were used in order to be tested, and the better ones to be implemented as a reliable method for monitoring levels of eutrophication in mountain glacial lakes areas. Results about dynamics of the eutrophicated area in the lakes are derived. Territories of the swamped areas in the lake were monitored and calculated for the selected time frame of the study. Area of the Seven Rila Lakes is endangered by the rapid eutrophication processes caused by the impact of climate change and the anthropogenic factor. Rila mountain glacial lakes are categorized as protected area included in Natura 2000 network. The results obtained in the study can be used and integrated for observations and studies of climate change at the local and regional level.