KARST AQUIFER DRAINING DURING DRY PERIODS

We analyzed hydrographs of five karst springs in southern Italy during the recession period using ten continuous years of daily discharge measurements and provided conclusions on the aquifer behavior under dry periods and droughts. A straight line was fitted to a semilogarithmic plot (log-discharge versus time), and the recession coefficient (the slope of the line generated from the equation) was calculated for each spring and for each year considered. A deviation from the straight line produced by a simple exponential decay of discharge through time provides information on the actual emptying rate of the aquifer compared to a simple exponential decline. If the recession coefficient decreases or increases, the aquifer is empting more slowly or more quickly than expected, respectively. Water level of a monitored well inside the karst catchment was also assessed and provided information on the water distribution into aquifers. The results describe the hydraulic behavior of karst aquifers during their emptying and provide information for better management of karst springs.