Groundwater flow evolution in the circum-Vesuvian plain, Italy

The variations in groundwater flow rates and direction of the plain around Vesuvius over the last twenty years were examined. The following aspects were found: an overall decline in the water table which is more pronounced to the east of Naples rather than the Sarno plain; several changes in the direction of groundwater now; a decrease in the size of the Sarno groundwater basin with a corresponding increase in the size of the basin east of Naples; a reduction in aquifer storage (approximately 56 x 10(6) m(3), between 1978 and 1993), amounting to 38% of average annual recharge. The main cause would seem to be increased pumping of the aquifer, which currently accounts for some 54% of groundwater outflow. Pumping particularly affects the groundwater resources of the plain lying east of Naples where it accounts for 98% of groundwater out flow.