Due to climate change, it has become essential and necessary to monitor the critical land masses of the Earth in this thesis we are going to see how the Belvedere glacier which is located in the northwest part of Italy in Italian alps can be monitored Earth observation technologies. Since this glacier is very unstable the local geomorphology of the glacier varies continuously with time and space, so it is not very safe to collect data on site using laser scanning and photogrammetric techniques etc. Thanks to advances in space science we can now monitor any part earth surface and atmospheric variables around any time of the year using active remote sensing and passive remote sensing .The main emphasis of this thesis is that DEM’s generated using stereo optical images pairs from Spot 5 satellite which belongs to passive remote sensing and SAR interferometry techniques using sentinel 1 radar images which belongs to active remote sensing and check the quality of DEM’S from both the approaches or technologies and try to answer the question are they are reliable to calculate the volume of the glacier lost over a period from 2003 to 2016 and compare the volume lost in the glacier to the discharge measured with Hydrologiska Byråns Vattenbalansavdelning(HBV) model used to analyse discharge in the catchment where the glacier is located for which essential climate variables such as precipitation, temperature and stream flow of the catchment are used as input to model the discharge in the catchment.