The largest Kuiseb River floods initiate at the basin's semi‐arid headwater. Downstream, along the hyperarid Namib Desert, these floodwaters are feeding shallow alluvial aquifers, the only available water for human activity and for the natural ecology. Here, we characterize the largest floods and their changing frequency and magnitudes using palaeohydrological methods. Along 120 km of the rivers canyon 35 palaeoflood deposit s...