Mixing enhancement mechanisms in aquifers affected by hydropeaking: Insights from flow-through laboratory experiments

In this study, we performed flow-through experiments to investigate transport processes in a laboratory setup mimicking an aquifer affected by hydropeaking. We performed five flow-through experiments: steady flow experiment, steady flow experiment with river system by keeping the head of both rivers equal to the groundwater table, and finally three transient flow experiments (that will be described in the texts as transient flow 1, transient flow 2 and transient flow 3) considering two time series of fluctuating river heads. We performed high-resolution image analysis, and depth-resolved, high-frequency sampling at the outlet of the flow-through chamber to monitor the evolution and the breakthrough of the tracer plume in the porous medium. The dataset contains: 1. The tracer concentration normalized by the initial concentration at the outlet of the flow-through chamber obtained from the optical analysis for the five experiments. 2. The tracer concentration normalized by the initial concentration obtained from the spectrophotometric analysis of the samples collected at the outlet of the flow-through chamber for the five experiments. 3. The results of the normalized second central spatial moments of the solute distribution (-), volumetric reactor ratio (-) and flux-related reactor ratio (-) for the five experiments.本研究开展渗流实验，以探究模拟受水文调峰影响含水层的实验室装置内的溶质运移过程。本次共开展五组渗流实验：定流实验、维持两河道水头与地下水位齐平的河道系统定流实验，以及三组考虑两类河道水头波动时间序列的非定流实验（文中将分别记为非定流1、非定流2与非定流3）。本研究通过高分辨率图像分析，以及渗流腔出口处的深度分辨高频采样，对多孔介质内示踪剂羽流的运移演化与突破过程进行监测。本数据集包含如下内容： 1. 五组实验中，通过光学分析获取的渗流腔出口处示踪剂浓度（以初始浓度归一化后的数据）； 2. 五组实验中，对渗流腔出口采集的样品进行分光光度分析得到的示踪剂浓度（以初始浓度归一化后的数据）； 3. 五组实验中，溶质分布归一化二阶中心空间矩（无量纲）、体积反应器比值（无量纲）及通量相关反应器比值（无量纲）的计算结果。