Cascade from water-energy dynamics, discharge to landscape in Africa

This study investigates how the cascade from water–energy dynamics to stream discharge and to landscapes across Africa, which plays a critical role in landscape shaping. We employed the Budyko framework to statistically identify five hydroclimatic clusters and extracted corresponding discharge and landscape metrics. Subsequently, Sankey diagram and structural equation modeling (SEM) were applied to delineate this cascade. The results reveal contrasting cascade configurations: humid regions are dominated by high baseflow and discharge, coupled with low discharge variability and recession rates. Conversely, arid regions exhibit the low baseflow and discharge alongside high variability and rapid recession. The stream junction angles and terrain slope decrease from humid to arid environments. SEM demonstrates that discharge is strongly regulated by water-energy dynamics; however, the discharge–landscape connection shifts from strongly positive in humid regions to weakly negative in arid ones. Meanwhile, the blurred links from discharge to landscape variables might indicated different hydrological controls (long-term stable discharge vs short-lived flashy discharge and stable groundwater recharge vs lack of groundwater). The clear chain of the cascade has the potential to develop theoretical framework for landscape evolution. The indistinct variable links, implying different hydrological controls, should be simultaneously incorporated in the cohesive modeling framework.