Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, Taiwan
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 hydra...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-12-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/13/24/3491 |
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| author | Yung-Chia Chiu Chun-Hung Chen Yun-Ta Cheng Wenfu Chen |
| author_facet | Yung-Chia Chiu Chun-Hung Chen Yun-Ta Cheng Wenfu Chen |
| author_sort | Yung-Chia Chiu |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-03-10T03:54:15Z |
| format | Article |
| id | doaj.art-8792c9b5d8ac4e538f8bb73a0fddac80 |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-10T03:54:15Z |
| publishDate | 2021-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-8792c9b5d8ac4e538f8bb73a0fddac802023-11-23T11:00:02ZengMDPI AGWater2073-44412021-12-011324349110.3390/w13243491Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, TaiwanYung-Chia Chiu0Chun-Hung Chen1Yun-Ta Cheng2Wenfu Chen3Institute of Earth Sciences, National Taiwan Ocean University, Keelung 20224, TaiwanWater Resources Planning Institute, Water Resources Agency, MOEA, Taichung 41350, TaiwanWater Resources Planning Institute, Water Resources Agency, MOEA, Taichung 41350, TaiwanDepartment of Environmental Engineering and Science, Chia Nan University of Pharmacy and Science, Tainan 71710, TaiwanThe 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.https://www.mdpi.com/2073-4441/13/24/3491variable-density groundwaterfreshwater headPingtung PlainTaiwan |
| spellingShingle | Yung-Chia Chiu Chun-Hung Chen Yun-Ta Cheng Wenfu Chen Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, Taiwan Water variable-density groundwater freshwater head Pingtung Plain Taiwan |
| title | Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, Taiwan |
| title_full | Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, Taiwan |
| title_fullStr | Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, Taiwan |
| title_full_unstemmed | Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, Taiwan |
| title_short | Using Freshwater Heads to Analyze Flow Directions in Saline Aquifers of the Pingtung Plain, Taiwan |
| title_sort | using freshwater heads to analyze flow directions in saline aquifers of the pingtung plain taiwan |
| topic | variable-density groundwater freshwater head Pingtung Plain Taiwan |
| url | https://www.mdpi.com/2073-4441/13/24/3491 |
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