To explore the characteristics of overland flow resistance under the condition of sparse vegetative stem coverage and improve the basic theoretical research of overland flow, the resistance characteristics of overland flow were systematically investigated under four slope gradients (S), seven flow discharges (Q), and six degrees of vegetation coverage (Cr). The results show that the Manning roughness coefficient (n) changes with the ratio of water depth to vegetation height (h/hv) while the Reynolds number (Re), Froude number (Fr), and slope (S) are closely related to vegetation coverage. Meanwhile, h/hv, Re, and Cr have strong positive correlations with n, while Fr and S have strong negative correlations with n. Through data regression analysis, a power function relationship between n and hydraulic parameters was observed and sensitivity analysis was performed. It was concluded that the relationship between n and h/hv, Re, Cr, Q, and S shows the same law; in particular, for sparse stem vegetation coverage, Cr is the dominant factor affecting overland flow resistance under zero slope condition, while Cr is no longer the first dominant factor affecting overland flow resistance under non-zero slope condition. In the relationship between n and Fr, Cr has the least effect on overland flow resistance. This indicates that when Manning roughness coefficient is correlated with different hydraulic parameters, the same vegetation coverage has different effects on overland flow resistance. Therefore, it is necessary to study overland flow resistance under the condition of sparse stalk vegetation coverage.

中文翻译：

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稀疏茎植被覆盖下的地表流阻规律

为探索植被稀疏覆盖条件下地表水流阻力特征，完善地表水流基础理论研究，系统研究了四种坡度（S）、七种流量（Q）、和六度植被覆盖度 ( Cr )。结果表明，曼宁粗糙度系数（n）随着水深与植被高度的比值（h / hv）而变化，而雷诺数（Re）、弗劳德数（Fr）和坡度（S）与植被密切相关。覆盖。同时，h / hv、Re和Cr与n有很强的正相关，而Fr和S与n有很强的负相关。通过数据回归分析，观察n与水力参数之间的幂函数关系，并进行敏感性分析。得出结论，n与h / hv、Re、Cr、Q和S之间的关系显示出相同的规律；特别是，对于稀疏的茎植被覆盖，Cr是影响零坡度条件下地表水流阻力的主导因素，而Cr不再是影响非零坡度条件下地表水流阻力的第一主导因素。在n和Fr的关系中，Cr对漫流阻力的影响最小。这表明当曼宁粗糙度系数与不同的水力参数相关时，相同的植被覆盖对地表流阻力的影响不同。因此，有必要研究稀疏茎秆植被覆盖条件下的地表水流阻力。