Modeling of water surface profile in non-prismatic compound channels

Abstract Estimating the water surface elevation of river systems is one of the most complicated tasks in formulating hydraulic models for flood control and floodplain management. Consequently, utilizing simulation models to calibrate and validate the experimental data is crucial. HEC-RAS is used to calibrate and verify the water surface profiles for various converging compound channels in this investigation. Based on experimental data for converging channels (θ = 5°, 9°, and 12.38°), two distinct flow regimes were evaluated for validation. The predicted water surface profiles for two relative depths (β = 0.25 and 0.30) follow the same variational pattern as the experimental findings and are slightly lower than the observed values. The MAPE for the simulated and experimental results is less than 3%, indicating the predicted HEC-RAS value performance and accuracy. Therefore, our findings imply that in the case of non-prismatic rivers, the proposed HEC-RAS models are reliable for predicting water surface profiles with a high generalization capacity and do not exhibit overtraining. However, the results demonstrated that numerous variables impacting the water surface profile should be carefully considered since this would increase the disparities between HEC-RAS and experimental data.