Characterization of karstic aquifer complexity using fractal dimensions

Abstract

The present study analyzes fractal dimensions for the daily discharge data series of 12 karstic springs registered over two decades in Northeast Hungary. Fluctuation in the observed data is frequent and irregular, producing rough time series. The level of roughness is measured by the fractal dimension defined in different ways and corresponds to the intensity of fluctuation. That, in turn, results from the structure of the karstic aquifer, its conduits’ geometry, and the water migration in them. In the given case of springs, p-variogram based fractal dimensions reflect the karstification level primarily. On the other hand, box-count and information dimensions are associated with mixing karstic and hydrothermal components when the latter is present. Therefore, the analysis of fractal dimensions of spring discharges may provide a way to obtain information on the complexity of the hidden subsurface conduits and the water flows in them in an exploratory and comprehensive way.