Morphological Changes of Sharp Bends in Response to Three Gorges Project Operation at Different Discharges
Dam construction often changes downstream fluvial processes by reducing sediment supply. Taking Tiaoguan reach and Laijiapu reach of the lower Jingjiang Reach downstream of the Three Gorges Project as examples, three-dimensional flow velocity, sediment, and bed elevation were observed in the two ben...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2022-05-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2022.876631/full |
| _version_ | 1811256527274639360 |
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| author | Hongyang Wang Hongyang Wang Shiming Yao Yongjun Lu Liqin Zuo Huaixiang Liu Zhanchao Zhao |
| author_facet | Hongyang Wang Hongyang Wang Shiming Yao Yongjun Lu Liqin Zuo Huaixiang Liu Zhanchao Zhao |
| author_sort | Hongyang Wang |
| collection | DOAJ |
| description | Dam construction often changes downstream fluvial processes by reducing sediment supply. Taking Tiaoguan reach and Laijiapu reach of the lower Jingjiang Reach downstream of the Three Gorges Project as examples, three-dimensional flow velocity, sediment, and bed elevation were observed in the two bends for investigating the impact of flow structure and sediment transport of different discharges on sharp bend morphology. Results indicated that the flow structure and sediment transport process in curved channels depended upon the flow stages, which affected the patterns of erosion and deposition along the point bars and concave banks. Flow separation and development of secondary flow were depended on the shapes of point bars and flow depths nearby, and the strength of secondary flow increased with flow discharge. The high flow discharges, which had high sediment carrying capacity and stream power, provided the main driving force for erosion on upstream point bar, thus the type and duration of floods were crucial factors in the morphological evolution of meandering bends. The reduction of sediment supply should be responsible for erosion on the point bars, causing the flow to migrate toward the convex banks. In meandering rivers with reduced sediment supply, retreats (push inward) of inner (convex) banks dominated advances (pull inward) of outer (concave) banks. In addition, the formation and development of concave-bank bars might relate particularly to meander curvature. This study is expected to constitute a reference for bank protection and river management in meandering bends downstream of reservoirs. |
| first_indexed | 2024-04-12T17:41:33Z |
| format | Article |
| id | doaj.art-722baf6c81e04edba8197251e91c320b |
| institution | Directory Open Access Journal |
| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-04-12T17:41:33Z |
| publishDate | 2022-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj.art-722baf6c81e04edba8197251e91c320b2022-12-22T03:22:47ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632022-05-011010.3389/feart.2022.876631876631Morphological Changes of Sharp Bends in Response to Three Gorges Project Operation at Different DischargesHongyang Wang0Hongyang Wang1Shiming Yao2Yongjun Lu3Liqin Zuo4Huaixiang Liu5Zhanchao Zhao6State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, ChinaState Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, ChinaKey Laboratory of River Regulation and Flood Control of Ministry of Water Resources, Changjiang River Scientific Research Institute, Wuhan, ChinaState Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, ChinaState Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, ChinaState Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, ChinaKey Laboratory of River Regulation and Flood Control of Ministry of Water Resources, Changjiang River Scientific Research Institute, Wuhan, ChinaDam construction often changes downstream fluvial processes by reducing sediment supply. Taking Tiaoguan reach and Laijiapu reach of the lower Jingjiang Reach downstream of the Three Gorges Project as examples, three-dimensional flow velocity, sediment, and bed elevation were observed in the two bends for investigating the impact of flow structure and sediment transport of different discharges on sharp bend morphology. Results indicated that the flow structure and sediment transport process in curved channels depended upon the flow stages, which affected the patterns of erosion and deposition along the point bars and concave banks. Flow separation and development of secondary flow were depended on the shapes of point bars and flow depths nearby, and the strength of secondary flow increased with flow discharge. The high flow discharges, which had high sediment carrying capacity and stream power, provided the main driving force for erosion on upstream point bar, thus the type and duration of floods were crucial factors in the morphological evolution of meandering bends. The reduction of sediment supply should be responsible for erosion on the point bars, causing the flow to migrate toward the convex banks. In meandering rivers with reduced sediment supply, retreats (push inward) of inner (convex) banks dominated advances (pull inward) of outer (concave) banks. In addition, the formation and development of concave-bank bars might relate particularly to meander curvature. This study is expected to constitute a reference for bank protection and river management in meandering bends downstream of reservoirs.https://www.frontiersin.org/articles/10.3389/feart.2022.876631/fullbend morphologyreduced sediment supplyflow structuresediment transportationpoint bar erosionconcave bank deposition |
| spellingShingle | Hongyang Wang Hongyang Wang Shiming Yao Yongjun Lu Liqin Zuo Huaixiang Liu Zhanchao Zhao Morphological Changes of Sharp Bends in Response to Three Gorges Project Operation at Different Discharges Frontiers in Earth Science bend morphology reduced sediment supply flow structure sediment transportation point bar erosion concave bank deposition |
| title | Morphological Changes of Sharp Bends in Response to Three Gorges Project Operation at Different Discharges |
| title_full | Morphological Changes of Sharp Bends in Response to Three Gorges Project Operation at Different Discharges |
| title_fullStr | Morphological Changes of Sharp Bends in Response to Three Gorges Project Operation at Different Discharges |
| title_full_unstemmed | Morphological Changes of Sharp Bends in Response to Three Gorges Project Operation at Different Discharges |
| title_short | Morphological Changes of Sharp Bends in Response to Three Gorges Project Operation at Different Discharges |
| title_sort | morphological changes of sharp bends in response to three gorges project operation at different discharges |
| topic | bend morphology reduced sediment supply flow structure sediment transportation point bar erosion concave bank deposition |
| url | https://www.frontiersin.org/articles/10.3389/feart.2022.876631/full |
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