Contemporary sediment fluxes were about one third of values reported for the 1980s for several tributaries of the Middle and Lower Danube. Factor analysis showed that model underestimations were correlated to Alpine and karst areas, whereas underestimations occurred in high seismicity areas of the Lower Danube. Sediment trapping in reservoirs and floodplain deposition was probably underestimated and counterbalanced by high stream deposition. Streambank degradation contributed about 5% of sediments, and appeared important in high stream power Alpine reaches. According to the model, most sediments were generated by hillslope erosion. Sediment fluxes appeared overestimated in some regions (Sava and Velika Morava), and underestimated in others (Siret-Prut and Romanian Danube), but unbiased elsewhere. Overall, basin-wide model performance was considered satisfactory. Percent bias in an independent dataset of annual sediment yields (SSY 689 data-entries in 95 stations median 52В t/km 2/y, IQR 20вЂ“151В t/km 2/y) was в€’В 21.5%. In the validation dataset (172 gauging stations 1457 data-entries, median 17В mg/L, IQR 10вЂ“28), median residual was 9В mg/L (IQR в€’В 9 +В 39В mg/L). SSC residuals (simulations-observations) median was 2В mg/L (IQR в€’В 14 +В 22В mg/L). Mean annual sediment concentrations (SSC) from 269 gauging stations (2968 station-year entries median 19В mg/L, interquartile range IQR 10вЂ“36В mg/L) were used for calibrating in-stream sediments. After hydrologic calibration, hillslope gross erosion and sediment yields were broadly calibrated using ancillary data (measurements in plots and small catchments, and national and European erosion maps). This study aimed at assessing current (1995вЂ“2009) sediment fluxes of the Danube Basin with SWAT model and identifying sediment budget knowledge gaps. Sediment management is of prior concern in the Danube Basin for provision of economic and environmental services.

Swat 4 direct ip