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Applying factor analysis combined with kriging and information entropy theory for mapping and evaluating the stability of groundwater quality variation in Taiwan.

Shyu GS, Cheng BY, Chiang CT, Yao PH, Chang TK - Int J Environ Res Public Health (2011)

Bottom Line: Groundwater quality demonstrated apparent differences between the northern and southern areas of Taiwan when divided by the Wu River.Approximately 52% of the monitoring wells in southern Taiwan suffered from progressing seawater intrusion, causing unstable groundwater quality.The method proposed in this study for analyzing groundwater quality inspects common stability factors, identifies potential areas influenced by common factors, and assists in elevating and reinforcing information in support of an overall groundwater management strategy.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Management, Tungnan University, Taipei County 222, Taiwan. gsshyu@mail.tnu.edu.tw

ABSTRACT
In Taiwan many factors, whether geological parent materials, human activities, and climate change, can affect the groundwater quality and its stability. This work combines factor analysis and kriging with information entropy theory to interpret the stability of groundwater quality variation in Taiwan between 2005 and 2007. Groundwater quality demonstrated apparent differences between the northern and southern areas of Taiwan when divided by the Wu River. Approximately 52% of the monitoring wells in southern Taiwan suffered from progressing seawater intrusion, causing unstable groundwater quality. Industrial and livestock wastewaters also polluted 59.6% of the monitoring wells, resulting in elevated EC and TOC concentrations in the groundwater. In northern Taiwan, domestic wastewaters polluted city groundwater, resulting in higher NH(3)-N concentration and groundwater quality instability was apparent among 10.3% of the monitoring wells. The method proposed in this study for analyzing groundwater quality inspects common stability factors, identifies potential areas influenced by common factors, and assists in elevating and reinforcing information in support of an overall groundwater management strategy.

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(a)∼(c) Distribution of the information entropy values for various hydrochemical parameters in common Factor 1; (d) ranks of information entropy values Factor 1 in Southwestern Taiwan.
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f5-ijerph-08-01084: (a)∼(c) Distribution of the information entropy values for various hydrochemical parameters in common Factor 1; (d) ranks of information entropy values Factor 1 in Southwestern Taiwan.

Mentions: To understand the extent of Factor 1 impact on groundwater quality in the southern area, the study area concentrated on monitoring wells located only in the coast area of Chianan Plain. Using the information entropy method to evaluate the stability of groundwater parameters in Factor 1 emphasized the correlation between factor scores and information entropy values as shown in Figures 5(a)–(c). Results of overlaying the contours of Factor 1 and the information entropy values of Factor 1 showed that all of the parameters except Ca2+ indicated that the monitoring wells with high information entropy values of parameters were located closely in the regions having high Factor 1 scores. This indicated that monitoring wells with high Factor 1 scores had relative poor groundwater quality stability. These monitoring wells aggregated in the coastal areas, so salinization obviously affected groundwater quality. Factor loading for Ca2+ was 0.729, lower than other parameters of Factor 1. However, Ca2+ fitted the criterion for selecting groundwater parameters, showing that Ca2+ is not a main control parameter in Factor 1. This finding could prove that additional analyses of groundwater quality uncertainty in this study assisted in understanding various groundwater parameters, and how the same pollution source affected those parameters.


Applying factor analysis combined with kriging and information entropy theory for mapping and evaluating the stability of groundwater quality variation in Taiwan.

Shyu GS, Cheng BY, Chiang CT, Yao PH, Chang TK - Int J Environ Res Public Health (2011)

(a)∼(c) Distribution of the information entropy values for various hydrochemical parameters in common Factor 1; (d) ranks of information entropy values Factor 1 in Southwestern Taiwan.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3118879&req=5

f5-ijerph-08-01084: (a)∼(c) Distribution of the information entropy values for various hydrochemical parameters in common Factor 1; (d) ranks of information entropy values Factor 1 in Southwestern Taiwan.
Mentions: To understand the extent of Factor 1 impact on groundwater quality in the southern area, the study area concentrated on monitoring wells located only in the coast area of Chianan Plain. Using the information entropy method to evaluate the stability of groundwater parameters in Factor 1 emphasized the correlation between factor scores and information entropy values as shown in Figures 5(a)–(c). Results of overlaying the contours of Factor 1 and the information entropy values of Factor 1 showed that all of the parameters except Ca2+ indicated that the monitoring wells with high information entropy values of parameters were located closely in the regions having high Factor 1 scores. This indicated that monitoring wells with high Factor 1 scores had relative poor groundwater quality stability. These monitoring wells aggregated in the coastal areas, so salinization obviously affected groundwater quality. Factor loading for Ca2+ was 0.729, lower than other parameters of Factor 1. However, Ca2+ fitted the criterion for selecting groundwater parameters, showing that Ca2+ is not a main control parameter in Factor 1. This finding could prove that additional analyses of groundwater quality uncertainty in this study assisted in understanding various groundwater parameters, and how the same pollution source affected those parameters.

Bottom Line: Groundwater quality demonstrated apparent differences between the northern and southern areas of Taiwan when divided by the Wu River.Approximately 52% of the monitoring wells in southern Taiwan suffered from progressing seawater intrusion, causing unstable groundwater quality.The method proposed in this study for analyzing groundwater quality inspects common stability factors, identifies potential areas influenced by common factors, and assists in elevating and reinforcing information in support of an overall groundwater management strategy.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Management, Tungnan University, Taipei County 222, Taiwan. gsshyu@mail.tnu.edu.tw

ABSTRACT
In Taiwan many factors, whether geological parent materials, human activities, and climate change, can affect the groundwater quality and its stability. This work combines factor analysis and kriging with information entropy theory to interpret the stability of groundwater quality variation in Taiwan between 2005 and 2007. Groundwater quality demonstrated apparent differences between the northern and southern areas of Taiwan when divided by the Wu River. Approximately 52% of the monitoring wells in southern Taiwan suffered from progressing seawater intrusion, causing unstable groundwater quality. Industrial and livestock wastewaters also polluted 59.6% of the monitoring wells, resulting in elevated EC and TOC concentrations in the groundwater. In northern Taiwan, domestic wastewaters polluted city groundwater, resulting in higher NH(3)-N concentration and groundwater quality instability was apparent among 10.3% of the monitoring wells. The method proposed in this study for analyzing groundwater quality inspects common stability factors, identifies potential areas influenced by common factors, and assists in elevating and reinforcing information in support of an overall groundwater management strategy.

Show MeSH