Determining the eutrophication status in Nainital lake of Uttarakhand, India using Sentinel-2 MSI imagery

Eutrophication is a crucial factor for the degradation of freshwater ecosystems. It has been noticed that in India several lakes have been already facing this type of adverse effect of eutrophication. Naini Lake is a fresh natural water body located in the Kumaon region of the Nainital district of Uttarakhand, and it is one of the most tourist destinations of India. With period it has been noticed that there has been a rise of eutrophication level in this lake. In this research systematic monitoring has been done to monitor the trophic status of the lake. Trophic State Index (TSI) was used to identify eutrophication. A combination of different environmental parameters of the lake and Sentinel-2 Multispectral Instrument (MSI) was used to model TSI. The spectral bands which were incorporated for chlorophyll detection are b5/b4 and b3/b4. Seven years of MSI data before the rainy season and after the rainy season have been collected from Jan 2017 to Dec 2023 to analyze the Chl-a, enabling a detailed evaluation of eutrophication trends in Naini Lake. The find out of the research show that the identification of the Chl-a using MSI data is an efficient and reliable method for monitoring of eutrophication.