Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, Taiwan
1
Institute of Earth Sciences, National Taiwan Ocean University, Keelung 20224, Taiwan
2
Water Resources Planning Institute, Water Resources Agency, MOEA, Taichung 41350, Taiwan
3
Department of Environmental Engineering and Science, Chia Nan University of Pharmacy and Science, Tainan 71710, Taiwan
*
Author to whom correspondence should be addressed.
Academic Editors: Fulin Li and Longcang Shu
Water 2021, 13(24), 3491; https://doi.org/10.3390/w13243491
Received: 25 October 2021
/
Revised: 1 December 2021
/
Accepted: 2 December 2021
/
Published: 7 December 2021
(This article belongs to the Special Issue Coastal Aquifers: Seawater/Saltwater Intrusion)
The hydraulic head is the most important parameter for the study of groundwater. However, a head measured from observation wells containing groundwater of variable density should be corrected to a reference density (e.g., a freshwater head). Some previous case studies have used unknown density hydraulic heads for calibrating flow models. Errors arising from the use of observed hydraulic head data of unknown density are, therefore, likely one of the most overlooked issues in flow simulations of seawater intrusion. Here, we present a case study that uses the freshwater head, instead of the observed hydraulic head, to analyze the flow paths of saline groundwater in the coastal region of the Pingtung Plain, Taiwan. Out of a total of 134 observation wells within the Pingtung Plain, 19 wells have been determined to be saline, with Electric Conductivity (EC) values higher than 1500 μS/cm during 2012. The misuse of observed hydraulic heads causes misinterpretation of the flow direction of saline groundwater. For such saline aquifers, the determination of a freshwater head requires density information obtained from an observation well. Instead of the purging and sampling method, we recommend EC logging using a month interval. Our research indicates that EC values within an observation well within saline aquifers vary not only vertically but also by season.
View Full-Text
Keywords:
variable-density groundwater; freshwater head; Pingtung Plain; Taiwan
▼
Show Figures
Figure 1
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
MDPI and ACS Style
Chiu, Y.-C.; Chen, C.-H.; Cheng, Y.-T.; Chen, W. Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, Taiwan. Water 2021, 13, 3491. https://doi.org/10.3390/w13243491
AMA Style
Chiu Y-C, Chen C-H, Cheng Y-T, Chen W. Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, Taiwan. Water. 2021; 13(24):3491. https://doi.org/10.3390/w13243491
Chicago/Turabian StyleChiu, Yung-Chia, Chun-Hung Chen, Yun-Ta Cheng, and Wenfu Chen. 2021. "Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, Taiwan" Water 13, no. 24: 3491. https://doi.org/10.3390/w13243491
Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.
