Monitoraggio idrologico nella Regione Valle d'Aosta

This work is about the monitoring of valley floor underground water, in Aosta Valley, and their relationship with superficial water; it has been realized with scientifical and applied purposes to classify the quantitative condition of groundwater bodies and to give informations about the future availability of underground water resource. Datas from piezometric measurements by ARPA Valle d'Aosta have been analysed and variations have been rapresented. It has been examinated the natural parameters (as flow of rivers, precipitations and air temperature), that can influence the variations of water table. Putting all the parameters together we can notice how temperature in high altitude, that causes the melting of snow and ice masses, is the main element that influences both piezometric and hydrological trends of rivers. Precipitations influence water table less even if winter abundant precipitations determinate a bigger snow accumulation in high altitude and a richer summer recharge. Quantitatively, water table conditions seem good, because water isn't over exploited in Aosta flat. Four lithostratigraphycal sections have been created that show how the entire area (until 90 meters, the maximun depth explored) is characterized by coarse alluvial mattress. With any drilling were achieved lacustrine silt and substratum identified by geophysical suerveys conducted in '70-`71. In the same flat it has been studied the geometrical relationship between river and water table - until now less known, even if important for evaluations of pollution ¿ and it has been made a relationship between underground and river water table measurements of Dora Baltea. Piezometric map shows that in west area (even if with some uncertainty) and in the middle area of Aosta flat the main amount of water comes from River Dora. In the east part River Dora drains water table. For a better knowledge of that relationship and of underground it is necessary to realize a set of piezometers made by continuous coring near the river. For a more detailed evaluation of piezometric trend some piezometers with probes connected to datalogger are necessary to measure continuously piezometric level.