| Extensive theory about groundwater depletion in karst aquifer reflected through spring recession curves has been developed. To skip theoretical presumptions about the analysis of karst spring recession, the concept of recession cloud has been introduced. The recession cloud is defined as set of all Nrec recession curves in the spring hydrogram. Inside of the apperent chaotic set of all recession discharges some statistical structures can be observed. The cloud could be described with the set of parameter curves (e.g average curve, median curve…). It has been shown that these curves can be modeled with simple exponential or power models. The model curves converge in one point at concentration time tc and concentration discharge Qc. On the basis of extreme value theory has been also shown that it is possible to model return period of the convergence. This convergence point is indicator of karstic aquifer development. |