Model-based clustering of hydrochemical data to demarcate natural versus human impacts on bedrock groundwater quality in rural areas, South Korea

Title
Model-based clustering of hydrochemical data to demarcate natural versus human impacts on bedrock groundwater quality in rural areas, South Korea
Author
박성숙
Keywords
Hydrochemistry; Bedrock groundwater quality; Model-based clustering; Normal (Gaussian) mixture model; Natural versus anthropogenic processes
Issue Date
2014-11
Publisher
ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Citation
JOURNAL OF HYDROLOGY, 권: 519, 페이지: 626-636
Abstract
Improved evaluation of anthropogenic contamination is required to sustainably manage groundwater resources. In this study, we investigated the hydrochemical measurements of 18 parameters from a total of 102 bedrock groundwater samples from two representative rural areas in South Korea. We used model-based clustering with a normal (Gaussian) mixture model to differentiate the contributions of natural versus anthropogenic processes to the observed groundwater quality. Water samples varied in hydrochemistry from a Ca-Na-HCO3 type to a Ca-HCO3-Cl type. The former type reflected derivation of major ions largely from water-rock interactions, while the latter type recorded varying degrees of anthropogenic contamination. Among the major dissolved ions, fluoride and nitrate were shown to be good indicators of the two types, respectively. The results of model-based clustering showed that the bivariate normal mixture model, which was based on the covariance of nitrate and fluoride, was more robust than multivariate analysis, and provided better discrimination between the anthropogenic and natural groundwater groups. Model-based clustering to measure the degree of cluster membership for each sample also showed a gradual change in groundwater chemistry due to mixing between the two water groups. This study provided an example of the successful application of model-based clustering to evaluate regional groundwater quality and demonstrated that better selection of the dimensional structure (i.e., selection of optimal variables and number of clusters) based on hydrochemistry was crucial in obtaining reasonable clustering results. (C) 2014 Elsevier B.V. All rights reserved.
URI
https://www.sciencedirect.com/science/article/pii/S0022169414005897?via%3Dihubhttp://hdl.handle.net/20.500.11754/51218
ISSN
0022-1694; 1879-2707
DOI
10.1016/j.jhydrol.2014.07.055
Appears in Collections:
RESEARCH INSTITUTE[S](부설연구소) > ETC
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