One dimensional sediment transport model to assess channel changes along Oltenita-Calarasi reach of Danube River, Romania

Sediment budget of the lower part of the Danube River has changed during the last decades, mainly due to the construction of dams and dykes. The objective of this study is to assess the sediment budget and morphological changes along Oltenita Calarasi Danube River reach, with the use of a one dimensional hydraulic and sediment transport model. The river schematic network was extracted from a Digital Terrain Model, built with topo bathimetric data, using HEC-GeoRAS. The hydrodynamic model was built, calibrated and validated with the 1D HEC-RAS software under unsteady flow regime, with hydrologic and sediment data from the period 2008-2011 at the two upstream and downstream gauging stations. Measured sediment discharge data were used to compute the suspended load with different transport functions. The function that represents the best fit for the observed values of suspended load in 2008 was used to model the hydromorphological behaviour of the river reach for the period 2009-2011. Computed sediment discharge values were found to follow the tendency of previous decades. The model was also used to assess possible changes of the channel bed by aggradation or degradation along the study reach, over the analysed period. (C) 2017 Published by Elsevier Ltd.