Transport of dissolved material on impermeable surface under artificial rainfall analyzed with the application of face-centered experimental design

ABSTRACT The study of surface runoff and transport of pollutants is of major importance, as it helps preventing environmental impacts, and supports planning tasks carried out by public authorities. The goal of this research was to study the dynamics of the transport of material (NaCl) on an impermeable surface, dissolved by the application of water through a rainfall simulator, having as its source of variation three independent variables: slope, rainfall intensity and position of the material. Face-centered experimental design was used, which contemplated different scenarios reproduced in the experiments, where the influence of the three independent variables on the dependent variables (transport time, peak value, peak time and total mass transported) was evaluated, whose responses were monitored at the outlet of the experimental model. The analysis of the results allowed to identify the significant effect of the slope and position of the material on all the dependent variables studied, as well as the quadratic effect of the slope for the transportation time and total mass transported. As for the rainfall intensity, only influence was observed for transportation time, within the study intervals with a level of significance of 95%. The resulting model is capable of explaining: 90% for transport time, 67.9% for peak value, 74.2% for peak time and 62.4% total mass transported.

摘要 地表径流与污染物输运研究具有重要意义，可助力环境影响防控并为公共管理部门的规划工作提供支撑。本研究旨在探究不透水表面上溶质（氯化钠，NaCl）的输运动态：该溶质通过降雨模拟器施加的水体溶解，实验设置三个自变量作为变化来源：坡度、降雨强度与溶质布设位置。本研究采用面中心实验设计，涵盖实验中复现的多种工况，评估了三个自变量对四类因变量（输运时间、峰值、峰值出现时间与总输运质量）的影响，实验模型出口处对上述响应指标进行了监测。结果分析表明，坡度与溶质布设位置对所有研究的因变量均存在显著影响；此外，坡度对输运时间与总输运质量存在二次效应。就降雨强度而言，在本研究的取值区间内，其仅对输运时间存在显著影响，显著性水平达95%。所构建的模型可分别解释输运时间90%的变异、峰值67.9%的变异、峰值出现时间74.2%的变异以及总输运质量62.4%的变异。