Dynamics of salt intrusion in the Mekong Delta: results of field observations and integrated coastal–inland modelling
<p>On the list of challenges facing the world largest deltas, increased saline water intrusion (SWI) in the surface water system and its role in jeopardizing freshwater supply are often ranked very high. Yet, detailed process-based studies of SWI at the whole delta scale are limited, and the t...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2021-08-01
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| Series: | Earth Surface Dynamics |
| Online Access: | https://esurf.copernicus.org/articles/9/953/2021/esurf-9-953-2021.pdf |
| _version_ | 1831795136482246656 |
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| author | S. Eslami S. Eslami P. Hoekstra H. W. J. Kernkamp N. Nguyen Trung D. Do Duc H. Nguyen Nghia T. Tran Quang A. van Dam S. E. Darby D. R. Parsons G. Vasilopoulos L. Braat M. van der Vegt |
| author_facet | S. Eslami S. Eslami P. Hoekstra H. W. J. Kernkamp N. Nguyen Trung D. Do Duc H. Nguyen Nghia T. Tran Quang A. van Dam S. E. Darby D. R. Parsons G. Vasilopoulos L. Braat M. van der Vegt |
| author_sort | S. Eslami |
| collection | DOAJ |
| description | <p>On the list of challenges facing the world largest deltas, increased saline water intrusion (SWI) in the surface water system and its role
in jeopardizing freshwater supply are often ranked very high. Yet, detailed process-based studies of SWI at the whole delta scale are limited, and
the trends are regularly associated with global sea level rise. Here, using field measurements and a sophisticated 3D model that integrates the
riverine, rural, estuarine, and coastal dynamics within one numerical domain, we study SWI at the scale of the Mekong Delta in extensive
detail. While many studies downscale the SWI problem to a topic within an estuary, we show that the physical processes on the continental shelf,
such as monsoon-driven ocean surge, directly influence salinity dynamics within the delta. Typical values of 20–40 <span class="inline-formula">cm</span> surge over the
continental shelf contribute to up to 10 <span class="inline-formula">km</span> of further SWI. The delta's estuarine system is also more sensitive than many other systems to
variations of river discharge. Furthermore, spring–neap variability plays a key role in SWI in the delta. The estuarine variability from a
stratified to a mixed system between neap and spring tides develops 3D processes such as estuarine circulation and tidal straining that become the
main upstream salt transport mechanisms. The 3D nature of salinity dynamics, and the role of upstream and downstream processes, suggests that
compromising on dimension or extent of the numerical domain can limit the accuracy of predictions of SWI in the delta. The study also showcases the fact that
riverbed incision in response to anthropogenic sediment starvation in the last 2 decades has increased stratification and activated or magnified
3D salt transport subprocesses that amplify upstream salt transport. With all the external forces on the delta, namely climate change and an altered
hydrological regime by the upstream dams, due to deeper estuarine channels (driven by sand mining and upstream impoundments) compared to its near
past, the delta itself has become far more vulnerable to even mild natural events. This exemplifies the fundamental importance of preserving the
sediment budget and riverbed levels in protecting the world's deltas against SWI.</p> |
| first_indexed | 2024-12-22T16:06:02Z |
| format | Article |
| id | doaj.art-e864b930728f42858492d9356ac16fb1 |
| institution | Directory Open Access Journal |
| issn | 2196-6311 2196-632X |
| language | English |
| last_indexed | 2024-12-22T16:06:02Z |
| publishDate | 2021-08-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Earth Surface Dynamics |
| spelling | doaj.art-e864b930728f42858492d9356ac16fb12022-12-21T18:20:37ZengCopernicus PublicationsEarth Surface Dynamics2196-63112196-632X2021-08-01995397610.5194/esurf-9-953-2021Dynamics of salt intrusion in the Mekong Delta: results of field observations and integrated coastal–inland modellingS. Eslami0S. Eslami1P. Hoekstra2H. W. J. Kernkamp3N. Nguyen Trung4D. Do Duc5H. Nguyen Nghia6T. Tran Quang7A. van Dam8S. E. Darby9D. R. Parsons10G. Vasilopoulos11L. Braat12M. van der Vegt13Department of Physical Geography, Faculty of Geoscience, Utrecht University, Utrecht, 3584 CB, the NetherlandsMarine and Coastal Systems Unit, Deltares, Delft, 2629 HV, the NetherlandsDepartment of Physical Geography, Faculty of Geoscience, Utrecht University, Utrecht, 3584 CB, the NetherlandsSoftware Department, Deltares, Delft, 2629 HV, the NetherlandsSouthern Institute for Water Resources Planning (SIWRP), Ho Chi Minh City, Ward 3 72710, VietnamSouthern Institute for Water Resources Planning (SIWRP), Ho Chi Minh City, Ward 3 72710, VietnamSouthern Institute of Water Resources Research (SIWRR), Ho Chi Minh City, 656 Võ Văn Ki\^{e}̣t, District 5, VietnamSouthern Institute for Water Resources Planning (SIWRP), Ho Chi Minh City, Ward 3 72710, VietnamSoftware Department, Deltares, Delft, 2629 HV, the NetherlandsGeography and Environment, University of Southampton, Southampton SO17 1BJ, UKDepartment of Geography, Environment and Earth Sciences, University of Hull, Hull HU6 7RX, UKDepartment of Geography, Environment and Earth Sciences, University of Hull, Hull HU6 7RX, UKDepartment of Geology and Planetary Sciences, California Institute of Technology, CA 91125, USADepartment of Physical Geography, Faculty of Geoscience, Utrecht University, Utrecht, 3584 CB, the Netherlands<p>On the list of challenges facing the world largest deltas, increased saline water intrusion (SWI) in the surface water system and its role in jeopardizing freshwater supply are often ranked very high. Yet, detailed process-based studies of SWI at the whole delta scale are limited, and the trends are regularly associated with global sea level rise. Here, using field measurements and a sophisticated 3D model that integrates the riverine, rural, estuarine, and coastal dynamics within one numerical domain, we study SWI at the scale of the Mekong Delta in extensive detail. While many studies downscale the SWI problem to a topic within an estuary, we show that the physical processes on the continental shelf, such as monsoon-driven ocean surge, directly influence salinity dynamics within the delta. Typical values of 20–40 <span class="inline-formula">cm</span> surge over the continental shelf contribute to up to 10 <span class="inline-formula">km</span> of further SWI. The delta's estuarine system is also more sensitive than many other systems to variations of river discharge. Furthermore, spring–neap variability plays a key role in SWI in the delta. The estuarine variability from a stratified to a mixed system between neap and spring tides develops 3D processes such as estuarine circulation and tidal straining that become the main upstream salt transport mechanisms. The 3D nature of salinity dynamics, and the role of upstream and downstream processes, suggests that compromising on dimension or extent of the numerical domain can limit the accuracy of predictions of SWI in the delta. The study also showcases the fact that riverbed incision in response to anthropogenic sediment starvation in the last 2 decades has increased stratification and activated or magnified 3D salt transport subprocesses that amplify upstream salt transport. With all the external forces on the delta, namely climate change and an altered hydrological regime by the upstream dams, due to deeper estuarine channels (driven by sand mining and upstream impoundments) compared to its near past, the delta itself has become far more vulnerable to even mild natural events. This exemplifies the fundamental importance of preserving the sediment budget and riverbed levels in protecting the world's deltas against SWI.</p>https://esurf.copernicus.org/articles/9/953/2021/esurf-9-953-2021.pdf |
| spellingShingle | S. Eslami S. Eslami P. Hoekstra H. W. J. Kernkamp N. Nguyen Trung D. Do Duc H. Nguyen Nghia T. Tran Quang A. van Dam S. E. Darby D. R. Parsons G. Vasilopoulos L. Braat M. van der Vegt Dynamics of salt intrusion in the Mekong Delta: results of field observations and integrated coastal–inland modelling Earth Surface Dynamics |
| title | Dynamics of salt intrusion in the Mekong Delta: results of field observations and integrated coastal–inland modelling |
| title_full | Dynamics of salt intrusion in the Mekong Delta: results of field observations and integrated coastal–inland modelling |
| title_fullStr | Dynamics of salt intrusion in the Mekong Delta: results of field observations and integrated coastal–inland modelling |
| title_full_unstemmed | Dynamics of salt intrusion in the Mekong Delta: results of field observations and integrated coastal–inland modelling |
| title_short | Dynamics of salt intrusion in the Mekong Delta: results of field observations and integrated coastal–inland modelling |
| title_sort | dynamics of salt intrusion in the mekong delta results of field observations and integrated coastal inland modelling |
| url | https://esurf.copernicus.org/articles/9/953/2021/esurf-9-953-2021.pdf |
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