Dynamics of hydrological droughts propagation in mountainous catchments

In the study, hydrological drought was identified assuming that the occurrence of river low-flow is a symptom of drought, and is also a good estimator of its progress. The research was conducted in the upper Dunajec river catchment, for which a series of daily discharges from 20 gauging stations during the period 1989–2018 were available. The low-flow periods were identified on the basis of the Threshold Level Method, which corresponds to the seventieth percentile of the flow duration curve. On the basis of a developed algorithm, 41 drought events were identified. Analysis included spatial parameters referring to range, severity, concentration, continuation, and the development pace of hydrological drought. Finally, on the basis of cluster analysis, five dynamic types of hydrological drought were identified.