Seasonal behaviour of tidal damping and residual water level slope in the Yangtze River estuary: identifying the critical position and river discharge for maximum tidal damping
<p>As a tide propagates into the estuary, river discharge affects tidal damping, primarily via a friction term, attenuating tidal motion by increasing the quadratic velocity in the numerator, while reducing the effective friction by increasing the water depth in the denominator. For the first...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2019-07-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/23/2779/2019/hess-23-2779-2019.pdf |
| _version_ | 1819264311350001664 |
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| author | H. Cai H. Cai H. Cai H. Cai H. H. G. Savenije E. Garel X. Zhang X. Zhang X. Zhang L. Guo M. Zhang F. Liu F. Liu F. Liu Q. Yang Q. Yang Q. Yang |
| author_facet | H. Cai H. Cai H. Cai H. Cai H. H. G. Savenije E. Garel X. Zhang X. Zhang X. Zhang L. Guo M. Zhang F. Liu F. Liu F. Liu Q. Yang Q. Yang Q. Yang |
| author_sort | H. Cai |
| collection | DOAJ |
| description | <p>As a tide propagates into the estuary, river discharge affects
tidal damping, primarily via a friction term, attenuating tidal motion by
increasing the quadratic velocity in the numerator, while reducing the
effective friction by increasing the water depth in the denominator. For the
first time, we demonstrate a third effect of river discharge that may
lead to the weakening of the channel convergence (i.e. landward reduction of
channel width and/or depth). In this study, monthly averaged tidal water
levels (2003–2014) at six gauging stations along the Yangtze River estuary
are used to understand the seasonal behaviour of tidal damping and residual
water level slope. Observations show that there is a critical value of river
discharge, beyond which the tidal damping is reduced with increasing river
discharge. This phenomenon is clearly observed in the upstream part of the
Yangtze River estuary (between the Maanshan and Wuhu reaches), which suggests
an important cumulative effect of residual water level on tide–river
dynamics. To understand the underlying mechanism, an analytical model has
been used to quantify the seasonal behaviour of tide–river dynamics and the
corresponding residual water level slope under various external forcing
conditions. It is shown that a critical position along the estuary is where
there is maximum tidal damping (approximately corresponding to a maximum
residual water level slope), upstream of which tidal damping is reduced in
the landward direction. Moreover, contrary to the common assumption that
larger river discharge leads to heavier damping, we demonstrate that beyond a
critical value tidal damping is slightly reduced with increasing river
discharge, owing to the cumulative effect of the residual water level on the
effective friction and channel convergence. Our contribution describes the
seasonal patterns of tide–river dynamics in detail, which will, hopefully,
enhance our understanding of the nonlinear tide–river interplay and guide
effective and sustainable water management in the Yangtze River estuary and
other estuaries with substantial freshwater discharge.</p> |
| first_indexed | 2024-12-23T20:27:28Z |
| format | Article |
| id | doaj.art-6a74878f4a0142c4bc15375917504198 |
| institution | Directory Open Access Journal |
| issn | 1027-5606 1607-7938 |
| language | English |
| last_indexed | 2024-12-23T20:27:28Z |
| publishDate | 2019-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Hydrology and Earth System Sciences |
| spelling | doaj.art-6a74878f4a0142c4bc153759175041982022-12-21T17:32:20ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382019-07-01232779279410.5194/hess-23-2779-2019Seasonal behaviour of tidal damping and residual water level slope in the Yangtze River estuary: identifying the critical position and river discharge for maximum tidal dampingH. Cai0H. Cai1H. Cai2H. Cai3H. H. G. Savenije4E. Garel5X. Zhang6X. Zhang7X. Zhang8L. Guo9M. Zhang10F. Liu11F. Liu12F. Liu13Q. Yang14Q. Yang15Q. Yang16Institute of Estuarine and Coastal Research/State and Local Joint Engineering Laboratory of Estuarine Hydraulic Technology, School of Marine Engineering and Technology, Sun Yat-sen University, Guangzhou, ChinaGuangdong Provincial Engineering Research Center of Coasts, Islands and Reefs, Guangzhou, ChinaSouthern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, ChinaState Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, ChinaDepartment of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, the NetherlandsCentre for Marine and Environmental Research (CIMA), University of Algarve, PortugalInstitute of Estuarine and Coastal Research/State and Local Joint Engineering Laboratory of Estuarine Hydraulic Technology, School of Marine Engineering and Technology, Sun Yat-sen University, Guangzhou, ChinaGuangdong Provincial Engineering Research Center of Coasts, Islands and Reefs, Guangzhou, ChinaSouthern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, ChinaState Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, ChinaShanghai Normal University, Department of Geography, Shanghai, ChinaInstitute of Estuarine and Coastal Research/State and Local Joint Engineering Laboratory of Estuarine Hydraulic Technology, School of Marine Engineering and Technology, Sun Yat-sen University, Guangzhou, ChinaGuangdong Provincial Engineering Research Center of Coasts, Islands and Reefs, Guangzhou, ChinaSouthern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, ChinaInstitute of Estuarine and Coastal Research/State and Local Joint Engineering Laboratory of Estuarine Hydraulic Technology, School of Marine Engineering and Technology, Sun Yat-sen University, Guangzhou, ChinaGuangdong Provincial Engineering Research Center of Coasts, Islands and Reefs, Guangzhou, ChinaSouthern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China<p>As a tide propagates into the estuary, river discharge affects tidal damping, primarily via a friction term, attenuating tidal motion by increasing the quadratic velocity in the numerator, while reducing the effective friction by increasing the water depth in the denominator. For the first time, we demonstrate a third effect of river discharge that may lead to the weakening of the channel convergence (i.e. landward reduction of channel width and/or depth). In this study, monthly averaged tidal water levels (2003–2014) at six gauging stations along the Yangtze River estuary are used to understand the seasonal behaviour of tidal damping and residual water level slope. Observations show that there is a critical value of river discharge, beyond which the tidal damping is reduced with increasing river discharge. This phenomenon is clearly observed in the upstream part of the Yangtze River estuary (between the Maanshan and Wuhu reaches), which suggests an important cumulative effect of residual water level on tide–river dynamics. To understand the underlying mechanism, an analytical model has been used to quantify the seasonal behaviour of tide–river dynamics and the corresponding residual water level slope under various external forcing conditions. It is shown that a critical position along the estuary is where there is maximum tidal damping (approximately corresponding to a maximum residual water level slope), upstream of which tidal damping is reduced in the landward direction. Moreover, contrary to the common assumption that larger river discharge leads to heavier damping, we demonstrate that beyond a critical value tidal damping is slightly reduced with increasing river discharge, owing to the cumulative effect of the residual water level on the effective friction and channel convergence. Our contribution describes the seasonal patterns of tide–river dynamics in detail, which will, hopefully, enhance our understanding of the nonlinear tide–river interplay and guide effective and sustainable water management in the Yangtze River estuary and other estuaries with substantial freshwater discharge.</p>https://www.hydrol-earth-syst-sci.net/23/2779/2019/hess-23-2779-2019.pdf |
| spellingShingle | H. Cai H. Cai H. Cai H. Cai H. H. G. Savenije E. Garel X. Zhang X. Zhang X. Zhang L. Guo M. Zhang F. Liu F. Liu F. Liu Q. Yang Q. Yang Q. Yang Seasonal behaviour of tidal damping and residual water level slope in the Yangtze River estuary: identifying the critical position and river discharge for maximum tidal damping Hydrology and Earth System Sciences |
| title | Seasonal behaviour of tidal damping and residual water level slope in the Yangtze River estuary: identifying the critical position and river discharge for maximum tidal damping |
| title_full | Seasonal behaviour of tidal damping and residual water level slope in the Yangtze River estuary: identifying the critical position and river discharge for maximum tidal damping |
| title_fullStr | Seasonal behaviour of tidal damping and residual water level slope in the Yangtze River estuary: identifying the critical position and river discharge for maximum tidal damping |
| title_full_unstemmed | Seasonal behaviour of tidal damping and residual water level slope in the Yangtze River estuary: identifying the critical position and river discharge for maximum tidal damping |
| title_short | Seasonal behaviour of tidal damping and residual water level slope in the Yangtze River estuary: identifying the critical position and river discharge for maximum tidal damping |
| title_sort | seasonal behaviour of tidal damping and residual water level slope in the yangtze river estuary identifying the critical position and river discharge for maximum tidal damping |
| url | https://www.hydrol-earth-syst-sci.net/23/2779/2019/hess-23-2779-2019.pdf |
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