Sediment transport functions in HEC-RAS 4.0 and their evaluation using data from sediment flushing of Wlingi reservoir - Indonesia

This paper presents a study carried out to assess the accuracy of several sediment transport functions commonly applied in HEC-RAS 4.0 against data from the sediment flushing of Wlingi reservoir in 2016. Another aim of this assessment is to evaluate the viability of selected transport equations to simulate riverbed changes during the sediment-flushing event. Thus, the best scenario of sediment flushing could be determined according to their efficiencies. The overall accuracy of the transport function indicated by RMSE values in descending order were those of Laursen-Copeland, Ackers and White, Meyer-Peter and Müller, and Wilcock formulas, when applied to the observed data. The study also indicated that Laursen-Copeland formula had parameters that were commonly well-characterized by the riverbed of Wlingi reservoir. Further, it was suitable to be utilised to assess the achievement of sediment flushing in Wlingi reservoir, while others seem less satisfactory.