We investigate the seasonal memory properties of a large sample of European rivers in terms of high and low flows. We compute seasonal correlations between peak and low flows and average flows in the previous seasons and explore the links with various physiographic and hydro-climatic catchment descriptors. Our findings suggest that there is a traceable physical basis for river memory which in turn can be employed to reduce uncertainty and improve probabilistic predictions of floods and droughts.

This work monitors the water consumed by the vegetation in two watersheds of Southern Spain for two years. An approach based on the reference evapotranspiration (ETo) and vegetation indices (VIs)-derived canopy coefficients is used (VI-ETo approach). A spatial analysis of ET of the main vegetation types was performed. The annual runoff, estimated with a simple water balance and using the ET, was similar to that obtained by the HBV model, which reproduces the river discharge at the outlet.

Assuming that floods are driven by both short- (meteorological forcing) and long-term perturbations (higher-than-usual moisture), we propose a technique for updating a season in advance the flood frequency distribution. Its application in the Po and Danube rivers helped to reduce the uncertainty in the estimation of floods and thus constitutes a promising tool for real-time management of flood risk mitigation. This study is the result of the stay of the first author at the University of Bologna.

Regulation by reservoirs affects both the freshwater regime and the sediment delivery downstream. Spain is one the countries with more water storage capacity by reservoirs in the world. The spatial redistribution of the seasonal and annual water storage in reservoirs mainly for irrigation and urban supply has resulted in significant environmental impacts downstream. This work shows these effects in the Guadalquivir and the Ebro River basins, two of the largest regulated areas in Spain.