Human impact on the hydrology of the Lake of Monate (Italy): an experimental data base to investigate anthropogenic disturbance

Abstract:

The Lake of Monate is located in the Lombardia region, in Northern Italy, close to the highest peaks of the Alps. The lake surface is about 2.5 square kilometers, with a maximum and mean water depth of 34 and 18 meters, respectively. Intensive agricultural cultivation and mining activities took place in the surrounding area since ancient times, as well as intensive urban and industrial development in the recent past. Notwithstanding the above anthropic activity, and the urbanization along the lake banks, the Lake of Monate is still close to pristine conditions, therefore being a unique example of ecosystem in equilibrium. The human impact is negligble because the lake has no tributaries, being the water inflow supplied by groundwater fluxes only, providing an average inflow volume of about 3.18 million of cubic meters. Since Roman times intensive mining activities are taking place in a large area that is located outside the geographical contributing catchment to the lake. In fact, the two mining sites of Cava Faraona and Cava Santa Maria are placed beyond the geographical divide between the Lake of Monate and the contiguous Lake of Ternate. However, the presence of subsurface rock layers that are tilted towards the Lake of Monate makes the actual contributing catchment more extended, therefore including the mining sites. For this reason, the recent decision to intensify the mining activities induced relevant concerns for the possible impact on the ecological equilibrium of the lake. Therefore, the local administration promoted an intensive monitoring campaign finalized to reach a better understanding of the hydrology of the lake and the subsurface water fluxes, to quantify the actual impact of the mining works. Meteorological and hydrological data at several location and fine time scale are being collected from Fall 2013 therefore putting together an experimental data set of relevant scientific value. This contribution aims to present the meteorological, hydrological and ecological data base of the Lake of Monate to the scientific community and the first findings on the hydrology of the lake and the hydrological disturbance induced by the mining activities. The results show that particular care should be taken when estimating the human impact in catchments where groundwater flow is the main driver of hydrological fluxes.