Salinity Profiles in Coastal Aquifers: A Characterization Framework for Field Measurements
Abstract The freshwater‐seawater mixing zone (“interface”) is affected by tides, seawater intrusion, submarine groundwater discharge and aquifer heterogeneities. Our current understanding is based primarily on theoretical studies involving numerical simulation and sand‐tank experimentation, with lim...
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| Format: | Article |
| Language: | English |
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Wiley
2024-06-01
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| Series: | Water Resources Research |
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| Online Access: | https://doi.org/10.1029/2024WR037244 |
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| author | Xinran Huang Adrian D. Werner S. Cristina Solórzano‐Rivas Amir Jazayeri |
| author_facet | Xinran Huang Adrian D. Werner S. Cristina Solórzano‐Rivas Amir Jazayeri |
| author_sort | Xinran Huang |
| collection | DOAJ |
| description | Abstract The freshwater‐seawater mixing zone (“interface”) is affected by tides, seawater intrusion, submarine groundwater discharge and aquifer heterogeneities. Our current understanding is based primarily on theoretical studies involving numerical simulation and sand‐tank experimentation, with limited field analyses of interface characteristics in coastal aquifers that serve as important freshwater reservoirs. The most common field evidence for interface characteristics is derived from electrical conductivity (EC) profiles, often obtained from long‐screen wells. However, the EC profiles from long‐screen wells have been assessed previously using only simple statistics like the depth to 50% of seawater concentration. This study introduces a methodology for characterizing EC profiles using curve fitting and objective assessment of multiple interface attributes, with application to 170 EC profiles from the Lower Burdekin Delta, Australia. The adopted fitting function showed an excellent match (mean R2 = 0.99). Fitting parameters were linked to the curvatures of transitions from fresh to brackish water and from brackish water to seawater, the elevation and gradient of the mid‐salinity value, and the thickness of the mixing zone. Field EC profiles showed approximately linear relationships between head changes averaged over the previous 5 months and the elevation of 5 mS/cm isochlor for some wells. The slope of this relationship was approximately one, which is approximately 1/40th of the value arising from the Ghyben‐Herzberg relation. The framework for characterizing salinity profiles presented in this article offers a new, objective approach for investigating the interface, providing future studies with a technique for examining relationships between interface behavior and key controlling forces. |
| format | Article |
| id | doaj-art-6f7e8517cfe540e0846f56c7a2f49b85 |
| institution | Kabale University |
| issn | 0043-1397 1944-7973 |
| language | English |
| publishDate | 2024-06-01 |
| publisher | Wiley |
| record_format | Article |
| series | Water Resources Research |
| spelling | doaj-art-6f7e8517cfe540e0846f56c7a2f49b852025-08-20T03:30:54ZengWileyWater Resources Research0043-13971944-79732024-06-01606n/an/a10.1029/2024WR037244Salinity Profiles in Coastal Aquifers: A Characterization Framework for Field MeasurementsXinran Huang0Adrian D. Werner1S. Cristina Solórzano‐Rivas2Amir Jazayeri3College of Science and Engineering Flinders University Adelaide SA AustraliaCollege of Science and Engineering Flinders University Adelaide SA AustraliaCollege of Science and Engineering Flinders University Adelaide SA AustraliaCollege of Science and Engineering Flinders University Adelaide SA AustraliaAbstract The freshwater‐seawater mixing zone (“interface”) is affected by tides, seawater intrusion, submarine groundwater discharge and aquifer heterogeneities. Our current understanding is based primarily on theoretical studies involving numerical simulation and sand‐tank experimentation, with limited field analyses of interface characteristics in coastal aquifers that serve as important freshwater reservoirs. The most common field evidence for interface characteristics is derived from electrical conductivity (EC) profiles, often obtained from long‐screen wells. However, the EC profiles from long‐screen wells have been assessed previously using only simple statistics like the depth to 50% of seawater concentration. This study introduces a methodology for characterizing EC profiles using curve fitting and objective assessment of multiple interface attributes, with application to 170 EC profiles from the Lower Burdekin Delta, Australia. The adopted fitting function showed an excellent match (mean R2 = 0.99). Fitting parameters were linked to the curvatures of transitions from fresh to brackish water and from brackish water to seawater, the elevation and gradient of the mid‐salinity value, and the thickness of the mixing zone. Field EC profiles showed approximately linear relationships between head changes averaged over the previous 5 months and the elevation of 5 mS/cm isochlor for some wells. The slope of this relationship was approximately one, which is approximately 1/40th of the value arising from the Ghyben‐Herzberg relation. The framework for characterizing salinity profiles presented in this article offers a new, objective approach for investigating the interface, providing future studies with a technique for examining relationships between interface behavior and key controlling forces.https://doi.org/10.1029/2024WR037244electrical conductivityfreshwater‐saltwater interfaceseawater intrusionfield measurementstransition zone |
| spellingShingle | Xinran Huang Adrian D. Werner S. Cristina Solórzano‐Rivas Amir Jazayeri Salinity Profiles in Coastal Aquifers: A Characterization Framework for Field Measurements Water Resources Research electrical conductivity freshwater‐saltwater interface seawater intrusion field measurements transition zone |
| title | Salinity Profiles in Coastal Aquifers: A Characterization Framework for Field Measurements |
| title_full | Salinity Profiles in Coastal Aquifers: A Characterization Framework for Field Measurements |
| title_fullStr | Salinity Profiles in Coastal Aquifers: A Characterization Framework for Field Measurements |
| title_full_unstemmed | Salinity Profiles in Coastal Aquifers: A Characterization Framework for Field Measurements |
| title_short | Salinity Profiles in Coastal Aquifers: A Characterization Framework for Field Measurements |
| title_sort | salinity profiles in coastal aquifers a characterization framework for field measurements |
| topic | electrical conductivity freshwater‐saltwater interface seawater intrusion field measurements transition zone |
| url | https://doi.org/10.1029/2024WR037244 |
| work_keys_str_mv | AT xinranhuang salinityprofilesincoastalaquifersacharacterizationframeworkforfieldmeasurements AT adriandwerner salinityprofilesincoastalaquifersacharacterizationframeworkforfieldmeasurements AT scristinasolorzanorivas salinityprofilesincoastalaquifersacharacterizationframeworkforfieldmeasurements AT amirjazayeri salinityprofilesincoastalaquifersacharacterizationframeworkforfieldmeasurements |