Dam-induced changes in river flow dynamics revealed by RQA

Abstract

The impact of dam construction on the river environment has been widely studied from various perspectives (e.g. biochemical, hydrological, ecological, geomorphological). To obtain new information, recurrence quantification analysis (RQA) is used to analyze the dynamics of mountain river flow and its changes caused by the construction of dam reservoirs with different parameters and functions. The analysis focuses on daily river flow for time periods before and after the construction of selected reservoirs in the Polish Carpathians. RQA shows that the reservoirs in question significantly changed the dynamics of the river flow in terms of the two considered complexity measures, indicating an increase in the regularity, autocorrelation and laminarity of the river flow dynamics for the river section below the reservoirs. Interestingly, the results suggest that the large complex of two reservoirs (Czorsztyn–Sromowce Wyżne) has a weaker impact on the dynamics of the river flow below the dam than the smaller Dobczyce reservoir; this may indicate an important role of the balancing reservoir (Sromowce Wyżne) in mitigating the changes taking place in the affected river system.