The contribution of time series analysis to the study of the hydrodynamic characteristics of the karst systems: Application on two typical karst aquifers of Greece (Trifilia, Almyros Crete)

Time series analysis was applied to the precipitation, spring discharge and piezometric head data of two representative karst systems of Greece in order to study the function, hydrodynamic behaviour and hydraulic properties of the aquifers. Results obtained through autocorrelation, spectral density, cross-correlation, cross-amplitude, gain, coherence and phase functions showed that the Trifilia karst system is slightly karstified and has a large storage capacity. Baseflow dominates while quickflow is absent due to the lack of a well-organized karst network, suggesting that, probably, Darcian conditions exist. On the other hand, unlike the Trifilia karst system, the karstification processes in the Almyros karst system are more enhanced producing a better developed karst network, but contrary to the typical karst systems, baseflow and quickflow coexist. This system can be classified as an intermediate case between the two extreme karst types.