Most of the water reservoirs of Pakistan are facing sedimentation problem. Mangla dam’s capacity, for instance, has been rapidly decreasing since it construction in 1967. The land cover changes, wether they are natural or man made, have huge impact. Vegetation cover and rainfall have an immense effect on the sediment load. The traditional techniques to analyze the problem are time consuming and spatially limited. Remote Sensing provides convenient way to observe the landcover changes and GIS provide tools for geographic analysis.

This study demonstrates a GIS oriented methodology to calculate the impact of vegetation and rainfall on sediment load by using remotely sensed data. MODIS data is used to observe the temporal change in vegetation covered area in Mangla watershed. The total drainage area for the Mangla is calculated from SRTM data. Annual rainfall is used to compute the annual available rainwater for the watershed. The impact of annual available rainwater on vegetation-covered area is computed in this study. In addition, certain areas are also identified which are causing sedimentation to reservoir. An inverse relation between the vegetation cover and rainwater is observed.