Autori: Xing F., A. J. Kettner, A. Ashton, L. Giosan, C. Ibáñez, J. O. Kaplan.
Editorial: Science of the Total Environment, 73/474, p.20-31, 2014.
Fluvial sediment discharge can vary in response to climate changes and human activities, which in return influences human settlements and ecosystems through coastline progradation and retreat. To understand the mechanisms controlling the variations of fluvial water and sediment discharge for the Ebro drainage basin, Spain, we apply a hydrological model HydroTrend. Comparison of model results with a 47-year observational record (AD 1953–1999) suggests that the model adequately captures annual average water discharge (simulated 408 cubic m per second versus observed 425 cubic m per second) and sediment load (simulated 0.3 Mt per year versus observed 0.28 ± 0.04 Mt per year) for the Ebro basin. A long-term (4000-year) simulation, driven by paleoclimate and anthropogenic land cover change scenarios, indicates that water discharge is controlled by the changes in precipitation, which has a high annual variability but no long-term trend. Modeled suspended sediment load, however, has an increasing trend over time, which is closely related to anthropogenic land cover variations with no significant correlation to climatic changes. The simulation suggests that 4000 years ago the annual sediment load to the ocean was 30.5 Mt per year which increased over time to 47.2 Mt per year (AD 1860–1960). In the second half of the 20th century, the emplacement of large dams resulted in a dramatic decrease in suspended sediment discharge, eventually reducing the flux to the ocean by more than 99% (mean value changes from 38.1 Mt per year to 0.3 Mt per year.
Cuvinte cheie: River discharge; Sediment flux; Dams; Human impacts; Land cover changes // River discharge; Sediment flux; Dams; Human impacts; Land cover changes