Utilizing multichannel electrical resistivity methods to examine the dynamics of the fresh water-seawater interface in two Hawaiian groundwater systems
Utilizing multichannel electrical resistivity methods to examine the dynamics of the fresh water-seawater interface in two Hawaiian groundwater systems
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DOI：
10.1029/2011jc007509
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发表时间：
2012-02-07
影响因子：
3.6
通讯作者：
Glenn, Craig R.
中科院分区：
文献类型：
--
作者：
Dimova, Natasha T.;Swarzenski, Peter W.;Glenn, Craig R.
多通道电阻率（ER）测量进行了对比在两个沿海站点在夏威夷获得新的信息的空间尺度和动态的淡水-海水界面和沿海地下水交换率。在Kiholo湾（位于大岛干燥的Kona一侧）和Maunalua湾（Oakland）的一个地点，有证据表明有大量的海底地下水排放（SGD）。然而，水文和地质控制沿海地下水排放可能是不同的，在这两个网站。在Kiholo湾，SGD主要通过熔岩管，而在Maunalua湾，站点交换主要通过近岸海底泉发生。为了计算SGD通量，重要的是要了解的空间和时间尺度的沿海地下水交换。根据ER时间序列数据，使用特定场地的地层因素计算地下盐度分布。然后使用盐度质量平衡箱模型来计算点源的速率（即，空间离散）和总淡水排放量。根据这些数据，计算出Kiholo湾（类似于9，200 m（3）/d）和Maunalua湾（类似于5，900 m（3）/d）的平均SGD率。虽然这样的结果是在同一数量级的地球化学示踪剂衍生的SGD率，ER SGD率提供了增强的沿海地下水交换的细节，可以使一个更有凝聚力的整个流域的观点。
Multichannel electrical resistivity (ER) measurements were conducted at two contrasting coastal sites in Hawaii to obtain new information on the spatial scales and dynamics of the fresh water-seawater interface and rates of coastal groundwater exchange. At Kiholo Bay (located on the dry, Kona side of the Big Island) and at a site in Maunalua Bay (Oahu), there is an evidence for abundant submarine groundwater discharge (SGD). However, the hydrologic and geologic controls on coastal groundwater discharge are likely to be different at these two sites. While at Kiholo Bay SGD is predominantly through lava tubes, at the Maunalua Bay site exchange occurs mostly through nearshore submarine springs. In order to calculate SGD fluxes, it is important to understand the spatial and temporal scales of coastal groundwater exchange. From ER time series data, subsurface salinity distributions were calculated using site-specific formation factors. A salinity mass balance box model was then used to calculate rates of point source (i.e., spatially discreet) and total fresh water discharge. From these data, mean SGD rates were calculated for Kiholo Bay (similar to 9,200 m(3)/d) and for the Maunalua Bay site (similar to 5,900 m(3)/d). While such results are on the same order of magnitude to geochemical tracer-derived SGD rates, the ER SGD rates provide enhanced details of coastal groundwater exchange that can enable a more cohesive whole watershed perspective.