25. Satellite-Based Monitoring of Water Quality in Mukutmanipur Dam: A Google Earth Engine Approach

Reservoirs play a vital role in water management, serving both irrigation and drinking water needs, yet they often face challenges related to pollution and water quality. This study examines the Mukutmanipur Dam in West Bengal, which provides irrigation and drinking water but is threatened by pollution and water quality degradation. To address these issues, we applied remote sensing techniques through the Google Earth Engine platform, utilizing Sentinel-2 data and several indices: the Normalized Difference Water Index (NDWI), Normalized Difference Chlorophyll Index (NDCI), and Normalized Difference Turbidity Index (NDTI). The NDTI was used to assess turbidity, revealing significant temporal fluctuations: the lowest turbidity values (−0.221 to −0.0503 in 2023) was observed in the winter months while the study revealed highest turbidity values (−0.125 to +0.0425 in 2023) during the monsoon. The NDCI was utilized to evaluate chlorophyll-a concentration, indicating higher levels in winter (NDCI range: While the NDCI value for different months in 2023 ranges from −0.276 to 0.195 for pre-monsoon and −0.171 to 0.0409 for monsoon, respectively. These indices combined create a body of understanding and perceptions of water quality and how it can be affected by various factors including fluctuations in seasons and human interference. This study shows that the indices based on satellite data can be useful for analysis of water quality, which may serve a guideline in the management of water resources and pollution issues.