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（surface runoff）与污染物输运（pollutant transport）研究具有重要学术与应用价值，其既可助力预防环境负面影响，也能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（impermeable surface）上物料（氯化钠，NaCl）的输运动态：该物料经降雨模拟器（rainfall simulator）施加的水体溶解后，在不透水表面发生输运过程；实验设置三类自变量（independent variables）作为变化来源，分别为坡度、降雨强度与物料布设位置。本研究采用面心实验设计（Face-centered experimental design），涵盖实验中复现的多种工况，以评估三类自变量对因变量（dependent variables）的影响，所关注的因变量包括输运时间、峰值、峰值时刻与总输运质量，并在实验模型的出口处监测这些因变量的响应数据。对实验结果的分析显示，坡度与物料布设位置对所有研究的因变量均存在显著影响；同时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，在本研究设定的区间内，其仅对输运时间存在显著影响，显著性水平达95%。所构建的回归模型可解释的变异比例分别为：输运时间90%、峰值67.9%、峰值时刻74.2%、总输运质量62.4%。