Assessment of alterations of river flow regimes using hydro-geomorphological parameters

Abstract

Climate change and anthropogenic activities can alter the streamflow regime by modifying critical elements of the flow regime. The aim of this work is to determine, by means of characteristic indices of rates of change and variability, the stage of alteration of the streamflow regime in a mountain catchment. On the basis of the daily mean streamflow, recorded over the period 1994-2020, a series of hydrological indices (Richards-Baker flashiness index, coefficient of variation, k index) were quantified, by means of which the rates of change and variability of the flow can be assessed. The results obtained show that the temporal and spatial variation of the streamflow is mainly due to natural causes, such as climatic variability and some geomorphological characteristics of the drainage basins. Thus, a clear positive correlation was observed between the Richards-Baker flashiness index and the magnitude of flood events. In the longitudinal profile, an increase in the mean values of Richards-Baker flashiness index was observed, indicating a higher variability of streamflows downstream. The higher Richards-Baker flashiness index values in the lower reaches were reflected in changes in the river channel, particularly after 2004.