Combined Effects of Unsteady River Discharges and Wave Conditions on River Mouth Bar Morphodynamics

Abstract River mouth bar formation, a key process in fluvial‐deltaic morphodynamics, is subject to both river discharge and waves. Given the increasing variability of both forcings under continuous climate change and human interventions, assessing their combined effects on mouth bar formation is an...

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Main Authors: Weilun Gao, Dongdong Shao, Zheng Bing Wang, William Nardin, Wei Yang, Tao Sun, Baoshan Cui
Format: Article
Language:English
Published: Wiley 2018-12-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2018GL080447
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author Weilun Gao
Dongdong Shao
Zheng Bing Wang
William Nardin
Wei Yang
Tao Sun
Baoshan Cui
author_facet Weilun Gao
Dongdong Shao
Zheng Bing Wang
William Nardin
Wei Yang
Tao Sun
Baoshan Cui
author_sort Weilun Gao
collection DOAJ
description Abstract River mouth bar formation, a key process in fluvial‐deltaic morphodynamics, is subject to both river discharge and waves. Given the increasing variability of both forcings under continuous climate change and human interventions, assessing their combined effects on mouth bar formation is an imperative issue. In this study, an extensive set of combined high and low river flows coupled with varying wave conditions and sediment grain sizes was assumed for numerical experiments conducted in Delft3D‐SWAN. The results suggested that three regimes existed for mouth bar formation, namely, stable, ephemeral, and absent. These regimes corresponded to consistently weak, initially‐weak‐then‐strong, and initially strong relative wave strengths, respectively, during the onset and reworking stages. Suppression of mouth bar formation further led to the inhibition of deltaic distributary networks. These findings have important implications for water and sediment management strategies, such as water diversion and dam regulation, in estuaries and deltas to prevent coastal erosion.
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institution OA Journals
issn 0094-8276
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language English
publishDate 2018-12-01
publisher Wiley
record_format Article
series Geophysical Research Letters
spelling doaj-art-39ea6d7f9d5346299d7412e62f96d23c2025-08-20T02:31:37ZengWileyGeophysical Research Letters0094-82761944-80072018-12-01452312,90312,91110.1029/2018GL080447Combined Effects of Unsteady River Discharges and Wave Conditions on River Mouth Bar MorphodynamicsWeilun Gao0Dongdong Shao1Zheng Bing Wang2William Nardin3Wei Yang4Tao Sun5Baoshan Cui6State Key Laboratory of Water Environment Simulation and School of Environment Beijing Normal University Beijing ChinaState Key Laboratory of Water Environment Simulation and School of Environment Beijing Normal University Beijing ChinaState Key Laboratory of Water Environment Simulation and School of Environment Beijing Normal University Beijing ChinaHorn Point Laboratory University of Maryland Center for Environmental Science Cambridge MD USAState Key Laboratory of Water Environment Simulation and School of Environment Beijing Normal University Beijing ChinaState Key Laboratory of Water Environment Simulation and School of Environment Beijing Normal University Beijing ChinaState Key Laboratory of Water Environment Simulation and School of Environment Beijing Normal University Beijing ChinaAbstract River mouth bar formation, a key process in fluvial‐deltaic morphodynamics, is subject to both river discharge and waves. Given the increasing variability of both forcings under continuous climate change and human interventions, assessing their combined effects on mouth bar formation is an imperative issue. In this study, an extensive set of combined high and low river flows coupled with varying wave conditions and sediment grain sizes was assumed for numerical experiments conducted in Delft3D‐SWAN. The results suggested that three regimes existed for mouth bar formation, namely, stable, ephemeral, and absent. These regimes corresponded to consistently weak, initially‐weak‐then‐strong, and initially strong relative wave strengths, respectively, during the onset and reworking stages. Suppression of mouth bar formation further led to the inhibition of deltaic distributary networks. These findings have important implications for water and sediment management strategies, such as water diversion and dam regulation, in estuaries and deltas to prevent coastal erosion.https://doi.org/10.1029/2018GL080447river mouth bardeltaic distributary networkunsteady river dischargecoastal wavesnumerical modeling
spellingShingle Weilun Gao
Dongdong Shao
Zheng Bing Wang
William Nardin
Wei Yang
Tao Sun
Baoshan Cui
Combined Effects of Unsteady River Discharges and Wave Conditions on River Mouth Bar Morphodynamics
Geophysical Research Letters
river mouth bar
deltaic distributary network
unsteady river discharge
coastal waves
numerical modeling
title Combined Effects of Unsteady River Discharges and Wave Conditions on River Mouth Bar Morphodynamics
title_full Combined Effects of Unsteady River Discharges and Wave Conditions on River Mouth Bar Morphodynamics
title_fullStr Combined Effects of Unsteady River Discharges and Wave Conditions on River Mouth Bar Morphodynamics
title_full_unstemmed Combined Effects of Unsteady River Discharges and Wave Conditions on River Mouth Bar Morphodynamics
title_short Combined Effects of Unsteady River Discharges and Wave Conditions on River Mouth Bar Morphodynamics
title_sort combined effects of unsteady river discharges and wave conditions on river mouth bar morphodynamics
topic river mouth bar
deltaic distributary network
unsteady river discharge
coastal waves
numerical modeling
url https://doi.org/10.1029/2018GL080447
work_keys_str_mv AT weilungao combinedeffectsofunsteadyriverdischargesandwaveconditionsonrivermouthbarmorphodynamics
AT dongdongshao combinedeffectsofunsteadyriverdischargesandwaveconditionsonrivermouthbarmorphodynamics
AT zhengbingwang combinedeffectsofunsteadyriverdischargesandwaveconditionsonrivermouthbarmorphodynamics
AT williamnardin combinedeffectsofunsteadyriverdischargesandwaveconditionsonrivermouthbarmorphodynamics
AT weiyang combinedeffectsofunsteadyriverdischargesandwaveconditionsonrivermouthbarmorphodynamics
AT taosun combinedeffectsofunsteadyriverdischargesandwaveconditionsonrivermouthbarmorphodynamics
AT baoshancui combinedeffectsofunsteadyriverdischargesandwaveconditionsonrivermouthbarmorphodynamics