Worldwide the processes of erosion, transport and sedimentation have a significant social, economic and environmental impact. In the past decade the most important external factor that has significantly increased the erosion and sediment process is the human factor throughout its daily activities. The changes of land cover and use, the intensive deforestation, urbanization and infrastructure development, sand extraction from river beds alter the natural watercourse and thus leading to erosion, sediment transportation and finally to the silting of rivers and reservoirs. The process of erosion and sedimentation occurs, among other areas, in the hydro-technical constructions with significant effects. In the next 30 years it’s expected to lose more than 50% of the storage capacity of the reservoirs in the world due to the silting phenomenon. The control and monitor of the sediment dynamics represents a critical component in the sustainable management of water resources. Also the understanding of the involved phenomena is essential in order to develop solution for reducing the sediment and erosion that occur and adopt measures to extend the life of the reservoirs. This paper taps the solution of mathematical modelling using dedicated software in order to establish the morphological changes that occur in Ogrezeni-Crivina reservoir, located on the river Arges.