A numerical model was used in the present study to predict aggradation, degradation, and subsurface moisture content in irrigation canals. The numerical model solved Saint‐Venant and sediment continuity equations to analyse overland flow and sediment transport, whereas Richard's equation was used to analyse subsurface movement of water. Saint‐Venant and sediment continuity equations were solved by using the MacCormack scheme based on the finite difference method, and the Richard's equation was solved by using a mass‐conservative fully implicit finite difference method. Extensive irrigation canal experiments involving measurement of aggradation, degradation, and subsurface moisture content were conducted to assess the performance of the numerical model. The predicted aggradation and degradation represented a good agreement with data recorded in laboratory. Soil moisture profiles were estimated for sediment‐laden water and clear water conditions in irrigation canals. But the effect of sediment‐laden water on the moisture profiles was observed as insignificant. The observed and the model‐predicted soil moisture varied marginally as the observed moisture was attributed to errors during the collection of soil samples from the experimental field.

中文翻译：

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考虑入渗的灌溉渠中凝结和降解的数值和实验研究*

在本研究中使用数值模型来预测灌溉渠中的凝结，降解和地下水分含量。数值模型求解了Saint-Venant和沉积物连续性方程，以分析陆上水流和沉积物的运移，而Richard方程则用于分析水的地下运动。使用基于有限差分法的MacCormack方案求解Saint-Venant和沉积物连续性方程，并使用质量守恒的完全隐式有限差分法求解Richard方程。进行了广泛的灌溉渠实验，包括对凝结，降解和地下水分含量的测量，以评估数值模型的性能。预计的沉淀和降解与实验室记录的数据吻合良好。估算了灌溉渠中含沙水和清水条件下的土壤湿度曲线。但是，观察到含沙水对水分分布的影响微不足道。观测到的水分和模型预测的土壤水分略有变化，因为观测到的水分归因于从实验场收集土壤样品期间的误差。