engleski

Temporal and spatial characterization of sediment transport through a karst aquifer by means of time series analysis

The process of sediment transport through a karst aquifer is investigated by means of time series analysis. The correlation and spectral analyses are used for determination of the temporal characteristics of this process, such as timing, synchronization with discharge from spring, and time delay between arrivals of sediment and infiltrated rainwater to spring. The partial correlation analysis is used for the spatial characterization. The study area is the catchment of Jadro Spring in Croatia. The analyzed hourly time series are discharge, water temperature, electrical conductivity, and nephelometric turbidity recorded at the source of this spring, as well as the rainfall collected at three locations in the catchment of spring. They cover the period of four years, from 2017 to 2020. The main aims of this research are (1) presentation of the methods of time series analysis that can be used for the investigation of sediment transport through karst aquifer, (2) analysis of the applicability of partial cross-correlation functions for the spatial characterization of sediment transport process, and (3) extension of the existing knowledge about the sediment in water from karst springs with a special reference to the Jadro Spring. The obtained results show that the partial cross-correlation function can be very useful in the investigation of mass transport through the karst aquifer. They enable identification of the specific contribution of each rain-gauge location to the quantity and quality of spring water. Specifically, the origin of sediment in water from Jadro Spring is determined in this study, as well as the origin of quick-flow and baseflow component in discharge from this spring, including the timing of fresh rainwater arrival, rainwater withdrawal, and emptying of previously accumulated water in vadose and phreatic zone. The sediment transport through the karst aquifer of Jadro Spring is initiated after heavy rainfall in the central and eastern part of the catchment. The origin of sediment in spring water is dominantly the remobilized autochthonous sediment from aquifer, and possible limited contribution of allochthonous sediment from the part of catchment located in hinterland of spring.

Karst hydrology ; Correlation and spectral analysis ; Partial cross-correlation function ; Turbidity ; Sediment transport ; Jadro Spring

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