A simple empirical method is proposed for computing the backwater level for different bridge shapes and crossings in compound channels. A series of parametric studies was conducted on the influence of the Froude number, opening ratio, discharge and roughness coefficient on the backwater depth. The results of the parametric studies, along with multiple regression analysis, were used to derive a simple accurate mathematical model for computing backwater depth. The proposed method was first compared with the energy method for different skew angles and roughness cases. Comparison of the results of the proposed method and the energy method showed good correlations. The proposed method was also validated by comparing its results with experimental data for normal and skewed crossings at 30° and 45°. The overall absolute average percentage difference between the proposed method and the experimental data was found to be 5.1%, while the overall root mean square error was found to be 0.008.

中文翻译：

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斜交桥收缩引起的回水水位的实证分析

提出了一种简单的经验方法来计算复合通道中不同桥梁形状和交叉点的回水位。弗洛德数，开口率，流量和粗糙度系数对回水深度的影响进行了一系列参数研究。参数研究的结果以及多元回归分析被用来得出一个简单的，精确的数学模型来计算回水深度。首先将所提出的方法与能量方法在不同的偏角和粗糙度情况下进行了比较。所提方法与能量方法的结果比较显示出良好的相关性。通过将其结果与30°和45°正常和倾斜交叉的实验数据进行比较，也验证了该方法的有效性。