Water hydrogeologucal bilance in the FVG Plain

One of the objectives of the European Directive 2000/60 and the Legislative Decree 152/06 is the sustainability of water-balance in a reference area with the aim of protecting water resources. Thorough verification of the water-balance it will be possible to obtain the consumption sustainable water value and, together with other protective measures planned, the achievement of environmental quality. The constantly increasing water demand for human consumptions and the constant use of water resources induced to study deeply the Friuli Venezia Giulia Plain (north eastern part of Italy) where all the water resources of the Region are storeged. The aim of the present research is to realize a water-balance in order to understand the amount of the water resource and its use. To reach this aim, the Geosciences Department from Trieste University has been engaged by the Hydraulic Survey of the FVG Region in order to coordinate an integrated study finalized to the Friuli Venezia Giulia Plain confined and unconfined aquifer geometries reconstruction and to provide guide-lines for water rational exploitation (Agreement D.G.R. n. 1827 dd. 27.07.2007). Water-balance means the comparison between the water resources (available or obtainable) in the reference area. In order to define water consumption, one Data Base with 52574 water-wells has been analyzed (of which 44980 are for domestic use). Domestic, drinking, agricultural, industrial, fishing industry and geothermal uses have been considered. Precipitation, evapotraspiration, runoff, infiltration and river discharge were used to obtain input and output water values from the regional system. As result, the High Plain recharge from the mountain basins in the Friuli Venezia Giulia Plain are abundant (202,5 m3/s) but also the water extractions are consistent (39-57 m3/s). The balance is not sustainable any more, some waters are really old and precious (19.000LGM years old – Cucchi et al., 2008), water table is subsiding 0,1-0,4 m/yr (Cucchi et al., 1999), the pressure of the confined aquifers is dropping and this imply a different policy geared towards a conscious use of the resource.