Author(s): Xiaonan Tang

Linked Author(s): Xiaonan Tang

Keywords: Overbank flow, compound channel flow, heterogeneous compound channel, zonal discharge, symmetric and asymmetric channels

Abstract: Accurate prediction of flow discharge in different parts of a compound river channel is increasingly important in river management, such as flood mitigation, eco-environment design, restoration and sediment transport. This paper compares four most recently developed 1-D methods, namely Interacting Divided Channel Method (IDCM), Energy Concept Method (ECM), Modified Divided Channel Method (MDCM) and Apparent Shear Stress Method (ASSM), against a wide range experimental data in this study and the data available in the literature. The 32 datasets used include heterogeneously roughened symmetric channels (22 datasets) and asymmetric channels (10 datasets) with various aspect ratios [channel total width (B) at bankfull / main channel bottom (b) =2. 6 ~ 15. 8], bed slopes (So = 4. 3x10-4 ~1. 3x10-2), and ratios of Manning's roughness between floodplain and main channel (1. 1 ~ 3. 9). It is found that none of the methods performed well against all the datasets. Compared with the traditional Divided Channel Method (DCM), all above methods, in general, predict both the total discharge and main channel discharge reasonably well within 12%, but they have relatively large errors for the prediction of the zonal discharge, particularly for floodplain with large roughness. The ASSM has shown the best overall performance on both the total and zonal discharge prediction

DOI:

Year: 2017