Search Results (2)

The Apuan Alps (Italy) are an internationally renowned karst region where several karst springs have a mean discharge exceeding 100 L/s, thus representing important water resources. One of the major springs, the Pollaccia, was monitored for approximately one year. This spring drains a structurally complex metamorphic karst aquifer that is characterized by multiple hydrologic sectors with variable recharge and infiltration styles. Spring discharge, water temperature, and electrical conductivity were compared to precipitation data, and time lag analysis was performed on 27 storm hydro/thermo/chemographs (HTC-graphs) that occurred in different hydrological phases. A marked seasonality was observed for all the monitored parameters and for the measured lags. The comparison of the storm HTC-graphs with no precipitation phases permitted recognition of the differential contribution of the various sectors. The Pollaccia’s hydrodynamic behavior was related to three different scenarios in the recharge area: (1) allogenic runoff recharge in the noncarbonate sectors; (2) autogenic recharge and runoff over the steeply dipping marble outcrops, characterized by fast epiphreatic flow through master conduits and low epikarst storage; (3) autogenic recharge through highly fractured, gently dipping marble outcrops, characterized by quick hydraulic pressure transfer to the phreatic zone and relevant epikarst storage. Full article

In this paper, we studied the geo-hydrological structure and behavior of a reference catchment, located in the Cilento UNESCO Global Geopark, southern Italy, representative of the hilly, terrigenous and forested headwaters of the Mediterranean eco-region. Based on detailed hydrogeological and hydro-geomorphological surveys and geomorphometric analysis, starting in 2012, a hydro-chemical monitoring activity at the catchment and sub-catchment scale started, and a hydro-chemical dataset was progressively recorded at daily and sub-hourly time steps. Based on this dataset, the authors performed an original procedure to identify different runoff components, derived by applying cascade mass balance filtering. The integration of hydrological and geomorphological approaches allowed us to obtain an interesting conceptualization of the storm flow generation using hydro-chemical signatures related to different runoff components produced during the increasing–decreasing cycle of the flood event magnitude. The hydro-system activated progressively different runoff sources (i.e., groundwater, riparian corridor, hillslope and hollow) and involved various mechanisms (i.e., groundwater ridging, saturation-excess, infiltration-excess and soil pipe exfiltration). The geo-hydrological conceptualization was validated using a hysteresis Q-EC loop analysis performed on selected events that showed how hysteretic indices could be used to characterize the events in respect to their origins, mechanisms and pathways in similar catchments. Full article