Analyses and forecast of water resources in an ultra-centenarian spring discharge series from Serino (Southern Italy)

Abstract

Summary Statistical and specific correlation data analyses have been carried out on anultra-centenarian hydrological series to establish the relationship between spring dis-charge and rainfall. Analyses focused on the Serino springs, the main spring area of thekarst aquifer in the Terminio massif (Southern Italy), which supplies the Naples area witha discharge of approximately 1–3.5 m 3 /s. Due to the Mediterranean climate, which causesa rapid increase in evapotranspiration and a decrease in rainfall towards spring–summer,spring discharge amplifies the effect of poor rainfall, especially during drought, andappears to be a highly sensitive climatic parameter. A specific index (cumulative effectiverainfall index, D i ) has been introduced to evaluate aquifer recharge. Its high correlationwith spring discharge made it possible to establish a cumulative effective rainfall thresh-old of 450 mm for aquifer response. Below this value, aquifer discharge exceeds rechargeand an ‘anomalous’ spring hydrograph is observed, which is precisely what occurred duringthe droughts of 1949 and 2002. Cross-correlation between moving cumulative rainfall anddaily spring discharge have shown a wide range of the water pore pressure transfer timeinside the Serino karst aquifer. Effects of changes in hydrological extremes are investi-gated, and frequency of droughts and spring discharge forecasting are also discussed.a 2007 Elsevier B.V. All rights reserved.