presas, crecidas, carga sólida, sedimentos en suspensión, carga de fondo
Abstract
Sediment transport continuity in the lower Ebro River is disrupted by the Mequinenza, Riba-roja and Flix Dams. This work presents the sediment budget of that river reach estimated from field measurements of suspended sediment and bedload taken regularly and during floods. Samples were collected upstream and downstream from the dams during the period 2002-2004. Total sediment load upstream from the dams is 3.28x106 t, of which 99% are transported in suspension. Downstream, the sediment load is 0.91x106 t, around 60% transported in suspension and the rest as bedload. Differences in the sediment-type load can be attributed both to the lack of fine sediment supply from upstream and to the magnitude of the flows released from the dams, which are competent enough to entrain and transport considerable amounts of the river’s bed-material. Bedload transport demonstrates that the riverbed of the lower Ebro is still highly active four decades after dams’ closure.
