Hydrologial and environmental history of a mediterranean river recorded in palaeoflood sediments

Trabajo presentado en el 5th International Paleoflood Meeting, celebrado en Rapid City (South Dakota, USA), del 12 al 15 de septiembre de 2016Rambla de la Viuda (drainage area of 1500 km2) is a Mediterranean ephemeral river with a hydrological regime characterised by large floods. The region has a long history of anthropogenic land-use changes, which contributed to temporal phases of increased rates of sediment yield and changes in flood hydrology. Valley sides revealed important accumulations of slackwater flood deposits. These slackwater flood deposits emplaced by high stage floodwaters show a complete stratigraphy from which we can reconstruct long-term records of floods and environmental changes. Interbeded with these flood units, colluvial units can be observed, and several edaphic horizons developed on colluvial and fluvial deposits were identified. The alluvial and colluvial chronostratigraphical, sedimentological and palaeobotanical (phytoliths) analysis of these units, together with the hydraulic flood modelling approach, made possible to determine: a) the way in which hydrological extreme events may be changing both in frequency and intensity as a result of climate variability, b) the weight of human influence (land-use) on soil hydrology, c) geomorphic channel changes, and c) the grade of resilience of landcover during this temporal scale (last 500 yrs).Peer reviewe