The role of bedrock groundwater in rainfall-runoff response at hillslope and catchment scales
The role of bedrock groundwater in rainfall-runoff response at hillslope and catchment scales
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DOI：
10.1016/j.jhydrol.2012.05.023
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发表时间：
2012-07
影响因子：
6.4
通讯作者：
J. McDonnell;C. Gabrielli;A. Thesis;J. McDonnell
中科院分区：
文献类型：
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作者：
J. McDonnell;C. Gabrielli;A. Thesis;J. McDonnell
在源头集水区基岩地下水动力学知之甚少，也不清楚。由于在陡峭、偏远和通常无路的地形中钻穿坚硬岩石所带来的后勤挑战，直接水文测量一直受到限制。我们使用了一种新的便携式基岩钻探系统，以探索基岩地下水动态，旨在量化基岩地下水对山坡径流和集水径流的贡献。我们目前的研究结果来自新西兰的Maimai M8研究集水区和美国俄勒冈州的H. J.安德鲁斯实验森林的分水岭10（WS 10）。在Maimai基岩地下水的分析，通过一系列的流量条件，显示基岩地下水位保持在土壤-基岩界面以下，表明基岩含水层有最小的直接贡献事件为基础的山坡径流。然而，基岩地下水位显着响应风暴事件表明，有一个山坡过程和下面的基岩含水层之间的直接联系。WS 10地下水动态以裂隙流为主。基岩上部一米范围内的一个高度断裂和透射区进行了快速的侧向地下暴雨流和侧向排放。地下暴雨流与基岩存储的相互作用直接影响测得的山坡响应，溶质运移和计算的平均停留时间。这项研究揭示了基岩地下水是一个非常动态的组成部分，山坡水文系统和我们的比较分析说明了潜在的范围内的水文和地质控制径流产生的源头集水区。
Bedrock groundwater dynamics in headwater catchments are poorly understood and poorly characterized. Direct hydrometric measurements have been limited due to the logistical challenges associated with drilling through hard rock in steep, remote and often roadless terrain. We used a new portable bedrock drilling system to explore bedrock groundwater dynamics aimed at quantifying bedrock groundwater contributions to hillslope flow and catchment runoff. We present results from the Maimai M8 research catchment in New Zealand and Watershed 10 (WS10) at the H.J. Andrews Experimental Forest in Oregon, USA. Analysis of bedrock groundwater at Maimai, through a range of flow conditions, revealed that the bedrock water table remained below the soil–bedrock interface, indicating that the bedrock aquifer has minimal direct contributions to event-based hillslope runoff. However, the bedrock water table did respond significantly to storm events indicating that there is a direct connection between hillslope processes and the underlying bedrock aquifer. WS10 groundwater dynamics were dominated by fracture flow. A highly fractured and transmissive zone within the upper one meter of bedrock conducted rapid lateral subsurface stormflow and lateral discharge. The interaction of subsurface stormflow with bedrock storage directly influenced the measured hillslope response, solute transport and computed mean residence time. This research reveals bedrock groundwater to be an extremely dynamic component of the hillslope hydrological system and our comparative analysis illustrates the potential range of hydrological and geological controls on runoff generation in headwater catchments.