Integrated Analysis of Turbidity–Discharge and Electrical Conductivity–Discharge Hysteresis Relationships for Interpreting the Hydrological Response of a Karst Spring

Karst springs are characterized by heterogeneous hydrological responses and complex dynamics of suspended material transport during rainfall events. This study aimed to improve understanding of the processes that determine the hydrological response of a karst aquifer by integrating analyses of the hysteretic relationships of turbidity–discharge and electrical conductivity–discharge. The analysis was based on measurements of rainfall, discharge, turbidity, and electrical conductivity during individual events at the Žrnovnica Spring, focusing on the types of turbidity–discharge and electrical conductivity–discharge hysteresis loops during periods when turbidity exceeded 4 NTU, and on the occurrence of isolated exceeding turbidity episodes. A total of 15 events with turbidity above 4 NTU were identified, dominated by complex hysteresis loops. The results show pronounced temporal variability in the system response and indicate the complexity of the flow, heterogeneous hydrological response, and time-delayed mobilization of previously accumulated sediment within the aquifer. The occurrence of isolated exceeding turbidity episodes during recessionary phases confirms the importance of internal redistribution of suspended material within the aquifer. The results show that an integrated interpretation of these hysteretic relationships can provide a useful approach for interpreting the hydrological processes and functioning of karst aquifers and has potential application to other karst sources.