Index-Based Spatiotemporal Assesment Of Water Quality In Tarbela Reservoir, Pakistan (1990−2020)

Anthropogenic activities can greatly influence the lake ecosystems across globe. Within these ecosystems, impacts of human are most evident on sedimentation, light and nutrient availability, disturbance frequency. There have been times natural environmental healing reservoirs present research aims to explore variations in water quality Tarbela reservoir, Pakistan largest rock-filled dam world, from 1990 2020. Landsat imagery (Landsat 4-5, 5, 7 8) was used monitor Land Use Cover (LULC), Normalized Difference Chlorophyll Index (NDCI), Turbidity (NDTI) Water (NDWI) its surrounding area 1990−2020, decadal interval. The results indicated a significant increase built-up area, about 630 km2 , western eastern parts whereas turbidity level, revealed substantial decline with 4% decrease observed last decade, 2010-2020 thus confirming improved quality. study also presented expanse spatial coverage chlorophyll index index, indicating residence time water. It is concluded that continued deteriorate time, however, 2020 year there an overall improvement reservoir observed. recommends policies be formulated for sediment flushing reduction longer duration enhance life this mega reservoir.