Drastic variations in estuarine morphodynamics in Southern Vietnam: investigating riverbed sand mining impact through hydrodynamic modelling and field controls
Recent riverbed sand mining activities have modified estuarine morphology and sedimentation patterns in many Southeast Asian deltas. The Soai Rap Estuary along the Dong Nai River (one of the largest rivers in Southern Vietnam) is one of the most intensively mined areas in the region, where large-sca...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
| Language: | English |
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2023
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| Online Access: | https://hdl.handle.net/10356/164019 |
| _version_ | 1811685092135796736 |
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| author | Anh, Le Ngoc Tran, Dung Duc Thong, Nguyen Van, Can Thu Vin, Dang Hoa Au, Nguyen Hai Park, Edward |
| author2 | Asian School of the Environment |
| author_facet | Asian School of the Environment Anh, Le Ngoc Tran, Dung Duc Thong, Nguyen Van, Can Thu Vin, Dang Hoa Au, Nguyen Hai Park, Edward |
| author_sort | Anh, Le Ngoc |
| collection | NTU |
| description | Recent riverbed sand mining activities have modified estuarine morphology and sedimentation patterns in many Southeast Asian deltas. The Soai Rap Estuary along the Dong Nai River (one of the largest rivers in Southern Vietnam) is one of the most intensively mined areas in the region, where large-scale sand mining activities have started since the 1990′s. In this paper, we used hydrodynamic modelling (TELEMAC-2D) to investigate the estuarine morphological changes and sediment dynamics related to the intensive riverbed mining in the Soai Rap Estuary. After the hydraulic calibration and validation of the model, we simulate four scenarios: two with dredging, one with sand excavation, and a baseline condition. Our results show that dredging substantially changed the hydraulic regimes, morphological and sediment dynamics of the estuary. Compared to the baseline, dredging substantially influences flow velocity and tidal amplitude. These activities reduce the amount of sediment accumulating upstream by 18% to 36%, while increasing sediment deposition in the Soai Rap Estuary by 6% to 13%. Furthermore, sediment accumulation in the Ganh Rai Bay area decrease by 5% to 10% due to increased sediment transport from the sea to the estuary. Our modelled results also show that the mining pits (pockmarks) created by sand extractions efficiently trap sediment, causing discontinuities in the longitudinal transport of sediment and resulting morphological patterns. We conclude that the morphology and sediment transport regime of the Soai Rap estuary has been significantly altered by the river sand dredging. As such, we recommend that the local government put in place measures to ensure that sand extraction is carried out sustainably in the future, to minimise further alterations to the natural sedimentation patterns and geomorphology of this estuary. |
| first_indexed | 2024-10-01T04:39:01Z |
| format | Journal Article |
| id | ntu-10356/164019 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T04:39:01Z |
| publishDate | 2023 |
| record_format | dspace |
| spelling | ntu-10356/1640192023-01-03T01:57:59Z Drastic variations in estuarine morphodynamics in Southern Vietnam: investigating riverbed sand mining impact through hydrodynamic modelling and field controls Anh, Le Ngoc Tran, Dung Duc Thong, Nguyen Van, Can Thu Vin, Dang Hoa Au, Nguyen Hai Park, Edward Asian School of the Environment National Institute of Education Earth Observatory of Singapore Social sciences::Geography Coastal Changes Hydrodynamic Recent riverbed sand mining activities have modified estuarine morphology and sedimentation patterns in many Southeast Asian deltas. The Soai Rap Estuary along the Dong Nai River (one of the largest rivers in Southern Vietnam) is one of the most intensively mined areas in the region, where large-scale sand mining activities have started since the 1990′s. In this paper, we used hydrodynamic modelling (TELEMAC-2D) to investigate the estuarine morphological changes and sediment dynamics related to the intensive riverbed mining in the Soai Rap Estuary. After the hydraulic calibration and validation of the model, we simulate four scenarios: two with dredging, one with sand excavation, and a baseline condition. Our results show that dredging substantially changed the hydraulic regimes, morphological and sediment dynamics of the estuary. Compared to the baseline, dredging substantially influences flow velocity and tidal amplitude. These activities reduce the amount of sediment accumulating upstream by 18% to 36%, while increasing sediment deposition in the Soai Rap Estuary by 6% to 13%. Furthermore, sediment accumulation in the Ganh Rai Bay area decrease by 5% to 10% due to increased sediment transport from the sea to the estuary. Our modelled results also show that the mining pits (pockmarks) created by sand extractions efficiently trap sediment, causing discontinuities in the longitudinal transport of sediment and resulting morphological patterns. We conclude that the morphology and sediment transport regime of the Soai Rap estuary has been significantly altered by the river sand dredging. As such, we recommend that the local government put in place measures to ensure that sand extraction is carried out sustainably in the future, to minimise further alterations to the natural sedimentation patterns and geomorphology of this estuary. Ministry of Education (MOE) Nanyang Technological University This study is funded by University of Natural Resources and Envi-ronment, Ho Chi Minh City, Vietnam under the grant number CS.2022.11. It is also funded by the Nanyang Technological University (#SUG-NAP EP3/19) and Ministry of Education of Singapore (#Tier1 RT06/19, #Tier1 2021-T1-001-056 and #Tier2MOE-T2EP402A20-0001). 2023-01-03T01:57:58Z 2023-01-03T01:57:58Z 2022 Journal Article Anh, L. N., Tran, D. D., Thong, N., Van, C. T., Vin, D. H., Au, N. H. & Park, E. (2022). Drastic variations in estuarine morphodynamics in Southern Vietnam: investigating riverbed sand mining impact through hydrodynamic modelling and field controls. Journal of Hydrology, 608, 127572-. https://dx.doi.org/10.1016/j.jhydrol.2022.127572 0022-1694 https://hdl.handle.net/10356/164019 10.1016/j.jhydrol.2022.127572 2-s2.0-85124544392 608 127572 en SUG-NAP EP3/19 RT 06/19 2021-T1-001–056 Journal of Hydrology © 2022 Elsevier B.V. All rights reserved. |
| spellingShingle | Social sciences::Geography Coastal Changes Hydrodynamic Anh, Le Ngoc Tran, Dung Duc Thong, Nguyen Van, Can Thu Vin, Dang Hoa Au, Nguyen Hai Park, Edward Drastic variations in estuarine morphodynamics in Southern Vietnam: investigating riverbed sand mining impact through hydrodynamic modelling and field controls |
| title | Drastic variations in estuarine morphodynamics in Southern Vietnam: investigating riverbed sand mining impact through hydrodynamic modelling and field controls |
| title_full | Drastic variations in estuarine morphodynamics in Southern Vietnam: investigating riverbed sand mining impact through hydrodynamic modelling and field controls |
| title_fullStr | Drastic variations in estuarine morphodynamics in Southern Vietnam: investigating riverbed sand mining impact through hydrodynamic modelling and field controls |
| title_full_unstemmed | Drastic variations in estuarine morphodynamics in Southern Vietnam: investigating riverbed sand mining impact through hydrodynamic modelling and field controls |
| title_short | Drastic variations in estuarine morphodynamics in Southern Vietnam: investigating riverbed sand mining impact through hydrodynamic modelling and field controls |
| title_sort | drastic variations in estuarine morphodynamics in southern vietnam investigating riverbed sand mining impact through hydrodynamic modelling and field controls |
| topic | Social sciences::Geography Coastal Changes Hydrodynamic |
| url | https://hdl.handle.net/10356/164019 |
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