Abstract When stormwater runoff flows into a constructed wetland, the water level changes inside, and the volume of the wetland changes accordingly. In this study, the relationship between pollutant removal and water depth flowrate changes was analyzed with velocity phase analysis, using the concepts of horizontal velocity and vertical velocity. A constructed wetland located in an agricultural area was used for the velocity phase analysis. Analysis results revealed that all four ponds and Phases I and III accounted for over 90% of the pollutant load. In particular, Phase III, where vertical and horizontal velocities were reduced, was responsible for approximately twice the load on average. The reason for the highest load in Phase III was due to the inflow of contaminants into the constructed wetland through the first flush effect occurred at the time when the flow rate decreased due to the difference in runoff strength. Therefore, it is necessary to maximize Phases I and III in the velocity phase when designing multi-stage wetlands to make the flow of water more natural. Furthermore, considering pollutant load levels, a design review is needed to expand the size of downstream wetlands, so that they can optimize water quality management functions.

中文翻译：

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农业面源污染治理人工湿地污染物负荷与水深流速变化关系分析

摘要 当雨水径流流入人工湿地时，其内部水位发生变化，湿地体积也随之发生变化。在这项研究中，利用水平速度和垂直速度的概念，通过速度相位分析来分析污染物去除与水深流速变化之间的关系。位于农业区的人工湿地用于速度相位分析。分析结果显示，所有四个池塘和一期和三期都占污染物负荷的90%以上。特别是，垂直和水平速度降低的阶段 III 造成的负载平均约为两倍。三期负荷最高的原因是污染物通过第一次冲刷效应流入人工湿地，此时由于径流强度差异导致流量下降。因此，在设计多级湿地时，需要在速度阶段最大化I和III阶段，使水流更自然。此外，考虑到污染物负荷水平，需要进行设计审查以扩大下游湿地的规模，以便优化水质管理功能。