Groundwater recharge estimation using spring hydrographs: the case of the Tennacola carbonate aquifer (central Apennine, Italy)

The recharge of an aquifer is fundamental to evaluate the availability of the resource and for planning its use over the time. In general, indirect methods are widely used, because these are based on the rainfall, evapotranspiration and runoff data. These three parameters are not always simple to evaluate in relation to the possible presence of errors in the available data, malfunction of instruments or difficulty to make a monitoring in relation to the complexity of the area, with consequent uncertainty on the results. In such situations, the use of a direct method could be useful to estimate more accurately the aquifer recharge. A common direct method is based on the analysis of the spring hydrographs, i.e. the discharge monitored at the spring. In this work, a spring hydrograph from the central Apennines of Italy has been analysed in order to estimate the average recharge value feeding the aquifer.