Simulation of Karst Springs Discharge in Case of Incomplete Time Series

Abstract

The difficulty in measuring spring discharge in mountainous regions often leads to incomplete time series, which are of low importance. Instead, the complete time series enable tο draw secure conclusions from the study of hydrographs. This article presents an innovative version of Modkarst model, which was originally developed to simulate the function of brackish coastal karst springs. Its originality is also related to its ability to complete time series and to give estimates with respect to important parameters of the karst aquifers, such as the storage coefficient and the extent of a spring’s recharge area. The new model, based on the fast and slow flow concept, uses two tanks instead of three and an appropriate modified system of equations from the initial one. Its inputs are time series of daily rainfall, while the model fitting requires discharge values. Its application area, Louros River basin, is a mountainous area consisting of 10 significant springs with yields varying between 0.07 and 3.4 m3/s, each of which discharges a hydrogeological karst unit. The validation of the model was accomplished by testing the accuracy of its results against a complete time series. Additional outputs, such as the estimated physical parameters, coincide with the outcomes from the hydrogeological investigation, thus confirming indirectly the code’s accuracy.