Reservoir sedimentation is the deposition of eroded sediment particles coming from the upstream catchment, becoming a critical problem for the storage capacity, useful life, and operation of the reservoir. Conventional methods for estimation of reservoir storage capacity and sediment volume, such as inflow-outflow technique, hydrographic, and integrated bathymetric surveys, are less time and cost-effective approaches and even consume a lot of manpower. In this study, to encounter the constraints of conventional techniques, LISS-III sensor satellite images and the GIS approach have been utilized to estimate sedimentation in the Barna reservoir. The Normalized Difference Water Index (NDWI) algorithm was employed to indicate and magnify the visualization of water pixels in satellite images. The analysis of this study shows that active storage capacity of Barna reservoir was decreased from 458.54 to 395.78 Mm3, hence 13.69% of live storage has been lost in the past 44 years (1975–2019). The yearly rate of siltation is 1.426 Mm3 or 0.31%. Moreover, the estimated rate of sedimentation has correlated with empirical relations of Varshney’s and Joglekar’s equations.