Using Hydrogeophysics to Monitor Change in Hyporheic Flow around Stream Restoration StructuresHydrogeophysics and Hyporheic Flow
Using Hydrogeophysics to Monitor Change in Hyporheic Flow around Stream Restoration StructuresHydrogeophysics and Hyporheic Flow
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利用水文地球物理学监测河流恢复结构周围潜流的变化水文地球物理学和潜流
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发表时间：
2012
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通讯作者：
R. Ryan
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作者：
L. Toran;Brian Hughes;J. Nyquist;R. Ryan
潜流交换是很重要的，因为通过河床的水通量影响微生物群落和水质，但很少有人知道的方式，它随着时间的推移而变化，特别是在响应流恢复。我们使用示踪剂测试和地球物理监测，沿着与河床表征，研究后的流恢复结构在克拉比溪，宾夕法尼亚州东南部的城市化流域建设的潜流区的演变。通过比较2009年和2010年以J形钩为中心的13.5米范围内的数据，对变化进行了评估。2009年和2010年，河床水井取样的穿透曲线非常相似，陡峭的上升和下降分支表明快速交换，随后在恢复到背景水平之前短暂（不到2小时）浓度略有升高。地下的电阻率断层扫描显示，在停止注入后，有残留的示踪剂区域。在J形钩上游，有一个残留示踪剂区域，在注射停止后持续超过3小时。这一缓慢交换的上游区域在这两年是相似的。在该结构的下游，2009年有挥之不去的示踪剂，但2010年的区域较小，强度较低。河床特征表明，20厘米的侵蚀发生在下游部分之间的两年，沿着与细粉的比例增加，这是与抑制hyporheic通量。电阻率剖面显示了残留示踪剂的区域，并有助于绘制仅从井采样中不明显的潜流区变化。
Hyporheic exchange is important because water flux through the streambed influences microbial communities and water quality, but little is known about the way in which it changes over time, particularly in response to stream restoration. We used tracer tests and geophysical monitoring, along with streambed characterization, to examine the evolution of the hyporheic zone after construction of a stream restoration structure at Crabby Creek, an urbanized watershed in southeastern Pennsylvania. Changes were assessed by comparing data from 2009 and 2010 over a 13.5 m reach centered on a J-hook. The breakthrough curves from streambed well sampling were remarkably similar in 2009 and 2010, with steep rising and falling limbs indicating rapid exchange followed by a short period (less than 2 hours) of slightly elevated concentration before returning to background levels. The resistivity tomographs of the subsurface showed areas of lingering tracer after the injection stopped. Upstream of the J-hook, there was an area of lingering tracer that persisted for more than 3 hours after the injection stopped. This upstream region of slow exchange was similar for both years. Downstream of the structure, there was lingering tracer in 2009, but a smaller, less intense region in 2010. Streambed characterization showed that 20 cm of erosion occurred in the downstream section between the two years, along with an increased proportion of fines, which was associated with inhibited hyporheic flux. The resistivity profiles showed areas of lingering tracer and helped map changes in the hyporheic zone that were not apparent from well sampling alone.