HYDRO-CSI, Project 1.2: In-stream hydrology. Part 1: Groundwater measurements

The continuous exchange of water between surface water and groundwater is a key environmental process controlling the transport and the fate of nutrients, solutes and pollutants in river networks. The dynamics of the near-stream groundwater has a non-negligeable role on controlling flow direction and solutes exchange between the stream water with the adjacent groundwater, however it is rarely considered in solute transport experiments. Despite the amount of individual studies, we are still uncertain about how the physical processes controlling in-stream solutes transport change with different hydrologic conditions and how these processes can be inferred by modelling outcomes. In this project we investigated groundwater and stream interactions in order to characterize the physical processes that control the water and solute exchange in the river corridor and their variability over time. To do so, we drilled 36 wells in the near-stream domain, and 7 piezometers in the stream channel. We observed the water level and electrical conductivity every 15 min at 22 of the 36 wells with a water level sensor (Orpheus Mini, OTT, Kempten, Germany, resolution of 1 mm and accuracy of ±0.05% FS) over a period of 32 months (July 2018 - March 2021). The dataset includes the following files: &gt; "Raw groundwater measurements.xlsx" <br> This file includes groundwater table elevation measured as depth from the upper limit of the well (time step of 15 minutes, Orpheus Mini, OTT, Kempten, Germany, resolution of 1 mm and accuracy of ±0.05% FS). Every excel file includes also Electrical Conductivity measurements (μS/cm) and Voltage (V) of the instruments. Every sheet in this .xlsx file reports measurement for one sensor in the specific observation-well where it was placed. &gt; "Groundwater elevation data - wells metadata and fixed groundwater table elevation.xlsx"<br> This file includes the raw groundwater table measurements measured via the OTT, information on the well network, elevation and location of the observation wells, location of subsurface layers, and suggested correction of the groundwater table measurements for short periods with missing data. &gt; "Hand-measurements and metadata.xlsx"<br> This file includes the list of in-situ inspections and hand-measurements of the groundwater table conducted over the entire observation period in every well and piezometer of the groundwater-monitoring well network. Every sheet includes details on the instruments measuring the groundwater table, their offset with hand-measured data, information on their re-calibration, and calculation of the groundwater elevation above the reference plane after each hand-measurement.地表水与地下水之间的持续水交换是控制河网中营养盐、溶质运移（solute transport）及污染物归趋的关键环境过程。近岸地下水的动力特性对控制河流水体与相邻地下水间的流向及溶质交换具有不可忽视的作用，但这类过程极少在溶质运移实验中被纳入考量范畴。尽管已有大量单项研究成果，我们仍无法明确控制河道内溶质运移的物理过程如何随不同水文条件（hydrologic conditions）发生变化，也不清楚如何通过模拟结果反推这些过程。本项目针对地下水与河流的交互作用展开研究，旨在表征控制河带内水与溶质交换的物理过程及其随时间的变异性。为此，我们在近岸区域钻取了36口观测井，并在河道内布设了7个测压管（piezometers）。在36口井中的22口中，我们使用水位传感器（Orpheus Mini，OTT，德国肯普滕，分辨率1 mm，精度±0.05% FS）每15分钟监测一次水位与电导率（electrical conductivity），监测周期为32个月（2018年7月至2021年3月）。 本数据集包含以下文件： > "Raw groundwater measurements.xlsx" 该文件包含以井顶为基准测得的地下水位埋深（时间步长15分钟，仪器为Orpheus Mini，OTT，德国肯普滕，分辨率1 mm，精度±0.05% FS）。每个Excel文件同时包含仪器采集的电导率（单位：μS/cm）与电压（单位：V）数据。该.xlsx文件的每个工作表对应一口观测井内的一台传感器的监测数据。 > "Groundwater elevation data - wells metadata and fixed groundwater table elevation.xlsx" 该文件包含通过OTT仪器采集的原始地下水位数据、观测井网信息、观测井的高程与位置、地下土层分布信息，以及针对短时缺失数据的地下水位修正建议。 > "Hand-measurements and metadata.xlsx" 该文件包含整个监测周期内，对地下水监测井网中所有观测井及测压管开展的原位巡查与地下水位人工测量记录。每个工作表详细记录了地下水位监测仪器的相关信息、与人工测量数据的偏差值、仪器重新校准情况，以及每次人工测量后参考平面以上地下水位高程的计算结果。