Lakes are surface water bodies whose balance is defined by inlows (from rivers, precipitation, groundwater) and outflows (discharge, evaporation, groundwater). Lakes are natural (or regulated) storages of water used by humans for several activities such as irrigation, fishing and energy production. Such uses of water are often in competition and represent the major challenge of water managers, expecially in the frame of climate change. The hydrological balance of the lake is an important step in the management of water and it has the aim of evaluating the inflows, outflows and volume change, considering att hydrological processes. The aim of thesis is to define the hydrological balance of the Como Lake.