Using cluster analysis for understanding spatial and temporal patterns and controlling factors of groundwater geochemistry in a regional aquifer
Using cluster analysis for understanding spatial and temporal patterns and controlling factors of groundwater geochemistry in a regional aquifer
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DOI：
10.1016/j.jhydrol.2020.124594
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发表时间：
2020-04
影响因子：
6.4
通讯作者：
Jing Yang;M. Ye;Zhonghua Tang;T. Jiao;Xiao-yu Song;Yongzhen Pei;Honghua Liu
中科院分区：
文献类型：
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作者：
Jing Yang;M. Ye;Zhonghua Tang;T. Jiao;Xiao-yu Song;Yongzhen Pei;Honghua Liu
由于缺乏数据和有效的统计方法来表征复杂的自然过程和人类活动，了解长期区域范围内地下水地球化学的时空模式具有挑战性。我们应用最近开发的聚类分析方法来研究中国江汉平原承压含水层地下水地球化学的时空格局和控制因素。聚类分析适用于 23 年来从分布在江汉平原的 29 个监测井采集的 1,184 个地下水样本的 13,024 个地下水地球化学测量数据，其中包括 11 个地球化学参数。聚类分析得出七个聚类的分类，并通过主成分分析和 Stiff 和 Piper 图确认了分类。根据七簇的空间分布，将江汉平原沿区域地下水流路划分为补给区、过渡区、流经区、排泄混合区四个地球化学区，这是以往未曾尝试过的。地下水地球化学的时间变化受水岩相互作用和人类活动的短期和长期因素控制。本研究的一个特别发现是，三峡水库对地下水地球化学具有长期影响，因为该水库在2009年之后增加了河流对地下水的流量。本研究表明，使用聚类分析方法与水文地球化学分析相结合，可以在长期监测期间识别区域尺度地下水地球化学的时空格局和控制因素。
Understanding spatial and temporal patterns of groundwater geochemistry at the regional scale over a long time period is challenging, due to the lack of data and effective statistical approaches to characterize complex natural processes and anthropogenic activities. We applied a recently developed cluster analysis method to investigate spatial and temporal patterns and controlling factors of groundwater geochemistry in the confined aquifer of the Jianghan Plain, China. The cluster analysis is applied to a dataset of 13,024 groundwater geochemical measurements for 11 geochemical parameters of 1,184 groundwater samples collected over 23 years from 29 monitoring wells distributed over the Jianghan Plain. The cluster analysis yielded a classification of seven clusters, and the classification was confirmed by using principal component analysis and Stiff and Piper diagrams. Based on the spatial distribution of the seven clusters, the Jianghan Plain is separated into four geochemical zones (i.e., recharge zone, transition zone, flow-through zone, and discharge-mixing zone) along the regional groundwater flow path, which has not been attempted in the past. The temporal changes of groundwater geochemistry are controlled by short- and long-term factors of water-rock interactions and anthropogenic activities. A particular finding of this study is that the Three Gorges Reservoir has a long-term impact on groundwater geochemistry, because the reservoir increased river discharge to groundwater after 2009. This study demonstrates that using the cluster analysis method together with hydrogeochemical analysis can identify spatiotemporal patterns and controlling factors of groundwater geochemistry at the regional scale over a long monitoring period.