ESTIMATING CHLOROPHYLL-A, CONCENTRATION USING SENTINEL-2 IMAGERY IN SELECTED LAKES OF KANYAKUMARI DISTRICT, TAMIL NADU, INDIA

Abstract

Water resources in India are very unpredictably distributed both spatially and temporally. Over the years, increasing population, urbanization and extension in agriculture and domestic water utilization has stressed the circumstances. Excessive algal growth due to eutrophication can have adverse effects on drinking water suppliers and end users. Monitoring of chlorophyll levels is the way to estimate the algal growth in water. Chlorophyll-a is one of the ecological indicators which is used to evaluate the status of the water bodies and its quality. Estimation of Chl-a had been carried out using in-situ data from Sentinel-2 imagery. For the present study, two lakes in Nagercoil districts - Parakkai Lake (P1, P2, and P3) and Therekal Lake (P4) were selected for the estimation of Chl-a using Sentinel-2 satellite imagery. Values of Chl-a concentration were estimated between 0.91-7.62 g/L for P1, whereas the values of P2 0.98-5.59 g/L and P3 the values range between 0.93- 5.43 g/L and Therekal lake (P4) is 0.97-7.01 g/L. Use of recent techniques like remote sensing and GIS (Geographical Information System) is still limited. Though the conventional methods give accurate values of Chl-a, but these results are not very helpful in providing a complete status of the whole water body. Estimation of Chl-a in water using the remote sensing techniques in integration with GIS which is associated with conventional methods.