In agro-urban environments, the water resource conveyed by rural channels is susceptible to a gradual impoverishment due to the continuous combined sewer overflow release, constituting a pending and urgent issue for water management companies and the entire community. Reliable one-dimensional longitudinal dispersion coefficients D are required to model and study the hydrodynamics and water quality patterns at the scale of rural channel networks. Empirical formulas are usually adopted to estimate D but the accuracy in the prediction could be questionable. In order to identify which are the most suitable formulas to determine D in rural channels, field tracer measurements were carried out in three rural channels with typical geometry and configuration. The obtained D values were then compared with the most commonly used predicting formulas that the literature provides. The accuracy of the predictors was further checked by simulating different flow rates inside the tested channels by using a one-dimensional hydraulic model. Starting from the obtained results, indications and guidelines to choose the most suitable formulas to predict D in rural channels were provided. These indications should be followed when developing realistic quality models in the agro-urban environments, especially in those cases where direct measurements of the longitudinal dispersion coefficient D are not available.

在农业城市环境中，农村渠道输送的水资源由于下水道连续溢流排放而易于逐渐减少，成为水务管理公司和整个社区悬而未决的紧迫问题。需要可靠的一维纵向离散系数D来模拟和研究农村渠道网络尺度的水动力和水质模式。通常采用经验公式来估计D，但预测的准确性可能存在问题。为了确定哪些是最合适的公式来确定D在农村信道中，在具有典型几何形状和配置的三个农村信道中进行了现场示踪剂测量。然后将获得的D值与文献提供的最常用的预测公式进行比较。通过使用一维水力模型模拟测试通道内的不同流速，进一步检查预测器的准确性。从获得的结果出发，提供了选择最合适的公式来预测农村渠道D 的指示和指南。在农业城市环境中开发实际质量模型时应遵循这些指示，尤其是在直接测量纵向分散系数D 的情况下 不可用。