Detecting ground water - surface water interaction in streams with DTS

Groundwater-surface water (GW-SW) flux measurement techniques, such as reach mass-balance, seepage meters, Darcian flux and temperature sensing can be applied simultaneously to provide multiple lines of evidence (e.g., Gonzalez et al. 2015, Schmadel et al. 2014, Kennedy et al. 2009, Gilmore et al. 2016b), but challenges remain for directly linking results from different spatial and temporal scales of measurement. For smaller streams where groundwater discharge is a significant percentage of stream discharge into the reach (typically ≥10%), the integrated groundwater flux from point measurements can be compared to a larger-scale (i.e. 10^2-10^3 m reach length) approach to confirm results. But for reaches in larger stream (river) systems, the stream-groundwater discharge ratio is usually much too large to use reach mass balance as a direct point of comparison (Gilmore et al. 2016b, Schmadel et al. 2010, Jain, 2000). A promising approach for linking point measurements and testing interpolation techniques in large river systems is fiber-optic distributed temperature sensing (FO-DTS) (Briggs et al. 2012a, Briggs et al. 2012b, Tyler et al. 2009). FO-DTS uses a fiber-optic cable to detect groundwater discharge through the streambed along the length of the cable (typically ≤1km). This may be an effective way to “connect the dots” between point measurements of groundwater discharge in large systems (Krause et al. 2012), when other techniques like reach mass balance, are not feasible. The overall goal of this research is to develop an optimal approach to link point measurements of groundwater-surface water fluxes in large river systems. The specific objectives are to: (1) test the combined DTS and point-measurement approach in a small stream, where interpolated results can be confirmed using a reach mass-balance approach, and (2) apply the technique in larger river systems to characterize spatial distributions and temporal variability of groundwater fluxes at existing groundwater-surface water monitoring stations on larger rivers. This project will improve techniques for multi-scale measurement of groundwater-surface water interactions, give critical insight into temporal and spatial variability of water fluxes in larger river systems, and improve our understanding of the value of existing groundwater-surface water monitoring stations.

Raw project data is available by contacting [e-mail]

地下水-地表水（GW-SW）通量测量技术，诸如河段质量平衡法、渗透计、达西通量以及温度感应等，可同时应用以提供多角度的证据支持（例如，Gonzalez 等人，2015年；Schmadel 等人，2014年；Kennedy 等人，2009年；Gilmore 等人，2016年b），但将不同空间和时间尺度测量结果直接关联仍存在挑战。对于地下水排放量占河段排放量较大比例（通常≥10%）的小型溪流，从点测量得到的综合地下水通量可以与较大尺度（即10^2-10^3米的河段长度）方法进行比较，以验证结果。然而，对于较大溪流（河流）系统中的河段，溪流-地下水排放比通常过于庞大，无法将河段质量平衡法作为直接比较的基准（Gilmore 等人，2016年b；Schmadel 等人，2010年；Jain，2000年）。将点测量与大型河流系统中的插值技术相结合的一种有前景的方法是光纤分布式温度感应（FO-DTS）（Briggs 等人，2012a；Briggs 等人，2012b；Tyler 等人，2009年）。FO-DTS 通过光纤电缆检测电缆长度方向上的溪床地下水排放（通常≤1公里）。这可能是连接大型系统中地下水排放点测量“ dots”之间的一种有效方法，当其他技术如河段质量平衡法不可行时。本研究的目标是开发一种将大型河流系统中地下水-地表水通量点测量结果关联起来的最优方法。具体目标包括：（1）在小型溪流中测试 DTS 与点测量相结合的方法，其中插值结果可以通过河段质量平衡法进行验证；（2）在大型河流系统中应用该技术，以表征现有地下水-地表水监测站点的空间分布和地下水通量的时间变化。此项目将改善多尺度测量地下水-地表水相互作用的技术，为大型河流系统中水通量的时空变化提供关键洞察，并增进我们对现有地下水-地表水监测站价值的理解。

原始项目数据可通过联系 [e-mail] 获取。