Towards sustainable sediment management strategies in Mediterranean reservoirs: Insights from the Guadalfeo semiarid river basin

The construction of reservoirs in semiarid Mediterranean basins dramatically affects reservoir siltation and coastal regression. The aim of this work was to characterize bedload sediment transport occurring upstream a reservoir in a semiarid Mediterranean river, and to assess sediment management strategies. A 8-km reach of the Guadalfeo River, upstream Rules dam in Southern Spain, was selected as study site. The December 2009 flood event, which meant a 3% of sedimentation, was analysed in detail. Field campaigns were conducted to assess bank erosion, bedload sediment transport and deposition in the reservoir tail. A 2D hydrodynamic and sediment transport model was used to reproduce the hydraulic conditions during the flood event and the associated transport processes. Management scenarios involving sediment relocation and check dam construction were evaluated, and new strategies for sediment transfer were designed. The results highlight the magnitude of the problem and the urgent need for sustainable sediment management strategies.