Sedimentologic approximation to reservoir situation and erosion in mountain basins: the barsona reservoir and the esera-isábena catchment (central pyrenees, huesca)

Abstract

A sedimentologic study of the Barasona reservoir (Central Pyrenees, Huesca province) and its catchment basin illustrates the spatial and temporal evolution of depositional processes in mountain basins. We analyze the sediment composition, identify sedimentary facies, and reconstruct the tri-dimensional geometry of the reservoir based on 20 cores and 3 profiles. Most of the sediment load to the Barasona reservoir is transported during flood events, which underlines the importance of the hydrologic regime of the rivers. Changes in mineral composition inform of sediment provenance and transport processes in the catchment are a. A preliminary chronology based on the identification of floods in the sedimentary record (sandy silt layers) allow to investigate the interaccions reservoir-catchment and changes in sedimentation rates through the last four decades. Physical factors as topography, lithology and drainage patterns appear to be majar controllers on soil erodibility. However, our study stresses the importance of human activity through changes in the use of the land. A better understanding of these processes is needed for suitable management of limited resources of soil and water and to alíviate reservoir sedimentation problems