Evaluation of sediment transport estimates using Sediment Routing Analysis (SRA) model: study case of Rawa Pening Lake

This study investigates sediment transport dynamics and the effectiveness of sediment control structures in Rawa Pening Lake and its sub-catchments using Sediment Routing Analysis (SRA) model. By analyzing sediment characteristics ranging from mud to gravel, the research highlights significant sedimentation rates that have led to an average loss of 12.65 million cubic meters in the lake's effective storage volume. Both quasi-unsteady and unsteady sediment transport models were employed, with the unsteady model demonstrating superior predictive capabilities. The empirical Ackers-White (A-W) equation surpassed the Meyer-Peter and Muller (M-P&M) equation, particularly in accurately representing the sediment characteristics and transport processes in Rawa Pening. This superiority is evidenced by a closer alignment between the A-W model's predictions and observed bathymetric measurements. The use of HEC-RAS software facilitated detailed simulations under various flow conditions, emphasizing the role of hydraulic parameters and topographic data in model accuracy. Sediment routing simulations reveal that while check dams effectively reduce sediment concentration, diversion structures, particularly Div-2, achieve up to a 91% reduction in sediment loads entering the lake. This highlights the critical importance of selecting appropriate sediment control structures based on their design and hydraulic conditions to optimize sediment management. Using SRA modelling developed in this study, the accuracy and robustness of the sediment deposition zone and the appropriate sediment control structures for practical engineering applications could be defined.