Hydrological balance of the Lake of Vico (Latium - Italy).

This paper presents the water budget of the Vico Lake, which is the smallest volcanic lake in Northern Latium (Central Italy); its average surface area is about 12 km2, while its catchment measures about 29 km2. The lake has one artificial outlet channel, and it is an important water resource; it is also a natural park. Due to the lack of continuous recordings of the outlet discharge, as well as the lack of data on the lake levels and evaporation, only a rough estimate of the average yearly lake balance was possible (time interval 1959-1996); however the results show that the outlet channel’s discharge accounts for about 40% of the water output from the lake: in fact, the outlet channel is what regulates the lake lev el. Water drawn from the lake for other uses is a negligible component of the water budget. The area is undergoing strong economic and tourist development, and without a proper planning and management, this can lead to the deterioration of the environmental conditions. This danger is enhanced by a climatic trend characterized by decreasing rainfall and increasing average yearly temperatures, linked to the “global climatic change” issue: the importance of the lake both as a nature reserve and as a water resource make it necessary to have a sound management plan, which has to be based on reliable hydrological and hydrogeological models. These tools can be set up only if an efficient data collection network is established.