Joint Assessment of the Behavior of Nitrate and Saltwater Intrusion Within Negative Hydraulic Barrier Setups
Abstract Nitrate is a common groundwater contaminant resulting from excessive agricultural fertilizer use, especially in coastal regions. Negative hydraulic barriers (NHBs) are widely used to mitigate seawater intrusion by altering groundwater behavior and pumping saline groundwater, but their impac...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2025-03-01
|
| Series: | Water Resources Research |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2024WR039047 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850114907381432320 |
|---|---|
| author | Shaobo Gao Tianyuan Zheng Jian Luo Xilai Zheng Yunhai Fang Marc Walther |
| author_facet | Shaobo Gao Tianyuan Zheng Jian Luo Xilai Zheng Yunhai Fang Marc Walther |
| author_sort | Shaobo Gao |
| collection | DOAJ |
| description | Abstract Nitrate is a common groundwater contaminant resulting from excessive agricultural fertilizer use, especially in coastal regions. Negative hydraulic barriers (NHBs) are widely used to mitigate seawater intrusion by altering groundwater behavior and pumping saline groundwater, but their impact on nitrate pollution remains unclear. This study investigated the mechanisms and impacts of NHBs on nitrate contamination using a 3D variable‐density model coupled with multi‐species transport simulations. We found that NHBs intensified nitrate accumulation near pollution sources, leading to the formation of high‐concentration zones. Nitrate removal was mainly through submarine groundwater discharge (SGD, accounting for 62.77%) before NHBs were introduced, but SGD efficiency dropped significantly (to 29.03%) after NHBs installation, with NHBs contributing 21.17%. Increasing NHBs pumping rates enhanced salt mass reduction and shifted nitrate removal toward NHBs‐based processes. Additionally, LH‐type aquifers, characterized by a low hydraulic conductivity (K) layer at the top, exacerbated nitrate retention and denitrification, while HL‐type aquifers, with a low K layer at the bottom, promoted horizontal diffusion and improved SGD. Furthermore, NHBs consistently intensified nitrate removal across different seawater boundary conditions. Our investigation highlights the importance of incorporating the effects of NHBs in the assessment of coastal nitrate pollution to avoid negative consequences associated with the barriers. |
| format | Article |
| id | doaj-art-57f6e7b3f6414bbc9c398d178b2fed02 |
| institution | OA Journals |
| issn | 0043-1397 1944-7973 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Water Resources Research |
| spelling | doaj-art-57f6e7b3f6414bbc9c398d178b2fed022025-08-20T02:36:42ZengWileyWater Resources Research0043-13971944-79732025-03-01613n/an/a10.1029/2024WR039047Joint Assessment of the Behavior of Nitrate and Saltwater Intrusion Within Negative Hydraulic Barrier SetupsShaobo Gao0Tianyuan Zheng1Jian Luo2Xilai Zheng3Yunhai Fang4Marc Walther5College of Environmental Science and Engineering Ocean University of China Qingdao ChinaCollege of Environmental Science and Engineering Ocean University of China Qingdao ChinaSchool of Civil and Environmental Engineering Georgia Institute of Technology Atlanta GA USACollege of Environmental Science and Engineering Ocean University of China Qingdao ChinaSchool of Resources and Environmental Engineering Hefei University of Technology Hefei ChinaFaculty of Environmental Sciences Department of Forest Sciences Chair of Forest Biometrics and Forest Systems Analysis Technische Universität Dresden Dresden GermanyAbstract Nitrate is a common groundwater contaminant resulting from excessive agricultural fertilizer use, especially in coastal regions. Negative hydraulic barriers (NHBs) are widely used to mitigate seawater intrusion by altering groundwater behavior and pumping saline groundwater, but their impact on nitrate pollution remains unclear. This study investigated the mechanisms and impacts of NHBs on nitrate contamination using a 3D variable‐density model coupled with multi‐species transport simulations. We found that NHBs intensified nitrate accumulation near pollution sources, leading to the formation of high‐concentration zones. Nitrate removal was mainly through submarine groundwater discharge (SGD, accounting for 62.77%) before NHBs were introduced, but SGD efficiency dropped significantly (to 29.03%) after NHBs installation, with NHBs contributing 21.17%. Increasing NHBs pumping rates enhanced salt mass reduction and shifted nitrate removal toward NHBs‐based processes. Additionally, LH‐type aquifers, characterized by a low hydraulic conductivity (K) layer at the top, exacerbated nitrate retention and denitrification, while HL‐type aquifers, with a low K layer at the bottom, promoted horizontal diffusion and improved SGD. Furthermore, NHBs consistently intensified nitrate removal across different seawater boundary conditions. Our investigation highlights the importance of incorporating the effects of NHBs in the assessment of coastal nitrate pollution to avoid negative consequences associated with the barriers.https://doi.org/10.1029/2024WR039047nitrate contaminationhydraulic barriersseawater intrusion3D model |
| spellingShingle | Shaobo Gao Tianyuan Zheng Jian Luo Xilai Zheng Yunhai Fang Marc Walther Joint Assessment of the Behavior of Nitrate and Saltwater Intrusion Within Negative Hydraulic Barrier Setups Water Resources Research nitrate contamination hydraulic barriers seawater intrusion 3D model |
| title | Joint Assessment of the Behavior of Nitrate and Saltwater Intrusion Within Negative Hydraulic Barrier Setups |
| title_full | Joint Assessment of the Behavior of Nitrate and Saltwater Intrusion Within Negative Hydraulic Barrier Setups |
| title_fullStr | Joint Assessment of the Behavior of Nitrate and Saltwater Intrusion Within Negative Hydraulic Barrier Setups |
| title_full_unstemmed | Joint Assessment of the Behavior of Nitrate and Saltwater Intrusion Within Negative Hydraulic Barrier Setups |
| title_short | Joint Assessment of the Behavior of Nitrate and Saltwater Intrusion Within Negative Hydraulic Barrier Setups |
| title_sort | joint assessment of the behavior of nitrate and saltwater intrusion within negative hydraulic barrier setups |
| topic | nitrate contamination hydraulic barriers seawater intrusion 3D model |
| url | https://doi.org/10.1029/2024WR039047 |
| work_keys_str_mv | AT shaobogao jointassessmentofthebehaviorofnitrateandsaltwaterintrusionwithinnegativehydraulicbarriersetups AT tianyuanzheng jointassessmentofthebehaviorofnitrateandsaltwaterintrusionwithinnegativehydraulicbarriersetups AT jianluo jointassessmentofthebehaviorofnitrateandsaltwaterintrusionwithinnegativehydraulicbarriersetups AT xilaizheng jointassessmentofthebehaviorofnitrateandsaltwaterintrusionwithinnegativehydraulicbarriersetups AT yunhaifang jointassessmentofthebehaviorofnitrateandsaltwaterintrusionwithinnegativehydraulicbarriersetups AT marcwalther jointassessmentofthebehaviorofnitrateandsaltwaterintrusionwithinnegativehydraulicbarriersetups |