Potential physical impacts of sea-level rise on the Pearl River Estuary, China

Hong, Bo; Liu, Zhonghui; Shen, Jian; Wu, Hui; Gong, Wenping; Xu, Hongzhou; Wang, Dongxiao

doi:10.1016/j.jmarsys.2019.103245

Cited by 56 publications

(65 citation statements)

References 53 publications

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“…Previous studies have investigated changes in SWI in several estuaries and deltas worldwide. River discharge variability and SLR have been found to be the main factors enhancing salinity intrusion in the Yangtze, Pearl, Changjiang, Mekong, Ganges, Brahmaputra, Meghna, and Nandu rivers (Akter et al., 2019; Bricheno & Wolf, 2018; Chen et al., 2016; He et al., 2018; Hong et al., 2020; Liu et al., 2019; Smajgl et al., 2015; Zhu et al., 2018). The results of this study confirm such general behavior.…”

Section: Discussionmentioning

confidence: 99%

“…Numerical models have been widely used to investigate salt transport in deltas and estuaries (Aristizabal & Chant, 2013; Hong et al., 2020; Liu et al., 2017; Lyu & Zhu, 2018; Shen et al., 2018; Tian, 2019). Generally, the boundaries of these models extend from the downstream portion of the drainage basin, where the major fraction of the river flow is naturally collected, to the coastal region.…”

Section: Introductionmentioning

confidence: 99%

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Saltwater Intrusion in a Mediterranean Delta Under a Changing Climate

et al. 2021

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Coastal zones are dynamic and sensitive to changing forcing conditions related to climate variability, such as flooding and droughts, storm surges, and sea-level changes. Among coastal systems, deltas and estuaries are characterized by complex dynamics between fresh water of continental origin and salt waters (Horner-Devine et al., 2015; Valle-Levinson, 2010). Moreover, deltas are impacted by human activities and in some cases the anthropic control on the natural environment can override the climatic signal, forcing deltas toward a man-made river-dominated system (Maselli & Trincardi, 2013). One of the major problems affecting deltas and estuaries, especially during drought conditions, is the upstream extent of the mixing zone between freshwater and saltwater. This would lead to a consequent increase of the salt content in aquifers and surface waters. Saltwater intrusion (SWI) in rivers can hinder the use of surface water for irrigation or drinking purposes and can threaten the livelihood of coastal communities that rely on fresh water supplies for their livelihood. Furthermore, when there is contact between the channel bed and the underlying coastal aquifer, saltwater can intrude and lead to salinization of soils (Werner et al., 2013; White & Kaplan, 2017). A variety of factors drives SWI on different spatial and temporal scales. These can be natural (sea level, storm surges, hurricanes, climate fluctuations, and subsidence) or anthropogenic (land drainage, exploitation of coastal aquifers, reduction in freshwater discharge from hydropower production and irrigation, interbasin diversions and other hydraulic infrastructures, changes in land-use within the drainage basin and channel deepening), as well as combinations of both (White & Kaplan, 2017). Therefore, understanding the processes controlling SWI and their effects under climate change is crucial for defining proper coastal mitigation and management strategies.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Saltwater Intrusion in a Mediterranean Delta Under a Changing Climate

et al. 2021

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“…The extensive damming of the Pearl River basin in recent decades has caused a considerable decrease in sediment discharge from the Pearl River watershed, which is mainly attributed to deposition in reservoirs (Dai et al, 2008;Tan et al, 2017). In addition, the global mean sea level and the sea level in the PRE have been rising in recent years at an increasing rate (Church & White, 2006;Hong et al, 2020). As the sea level in the PRE rises, the tidal range will increase, especially in the upper estuary (Hong et al, 2020).…”

Section: Comparison With Previous Studies and Implications For Future Morphological Evolution Of The Prementioning

confidence: 99%

Wave Effects on Sediment Transport and Entrapment in a Channel‐Shoal Estuary: The Pearl River Estuary in the Dry Winter Season

et al. 2021

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Sediment dynamics have substantial effects on the morphology of estuaries and deltas (Wright & Coleman, 1973) and have an enormous influence on estuarine and marine environments (Turner & Millward, 2002). Sediment transport and distribution in estuaries are heavily affected by river's discharge of freshwater and sediment, and by tides, winds, waves, and bathymetry (Dyer, 1997).The supply of river sediments to many estuarine systems has decreased over the past 50 years, especially in Africa and Asia, due to upstream damming and sand extraction (Syvitski et al., 2005(Syvitski et al., , 2009. This reduction in sediment input alters the morphology of estuaries, deltas, and coasts, and leads to depletion of the Abstract Sediment dynamics have great effects on the morphology of estuaries and deltas. As riverine sediment input has decreased in many estuaries in recent years, the removal and dispersion of sediments by currents and waves inside estuaries has assumed a more dominant role; however, the overall effects of waves are less well understood. In this study, we used the Coupled Ocean Atmosphere Wave Sediment Transport system to model the effects of waves on sediment transport in China's Pearl River Estuary. The results indicate that the presence of waves increased the landward current and sediment transport at the bottom of the channel and the seaward fluxes of water and sediment at the West Shoal, which is the main shallow area that accepts riverine sediment. Relative to the case without waves, the effects of waves increased the estuary's total sediment export by 45% to 9.14 megatons in one typical year, which even exceeded the annual riverine load in the year. The dry winter season shows the highest wave effects on sediment budget, and the sediment export was increased by 86% to 2.59 megatons with waves when compared with that without waves. This increase export was mainly concentrated at the surface near the western shore. Moreover, the waves increased lateral sediment entrapment in the Southwest Shoal, which explains the local geomorphologic evolution in recent decades. This study is of implication for the study on sediment exchange between shoal and channel in estuaries and on the fates of riverine sediment from source to sink.Plain Language Summary Waves have significant impacts on estuarine mixing, circulation, and sediment dynamics, which may affect the morphology of estuaries and deltas, water quality, and the overall estuarine ecosystems. Despite these substantial effects, the mechanisms of wave effects affecting estuarine circulation and lateral sediment entrapment in a channel-shoal estuary have not received adequate attention. Here, we use a validated coupled ocean model system to investigate the wave effects on longitudinal/lateral circulation and sediment transport/entrapment in a channel-shoal estuary. We note that the waves influence the surface and bottom stress, vertical mixing, and sediment resuspension. And in turn, these lead to the enhancement of tidal asymmetries and seaward sediment flux. M...

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“…To understand its impact, the saltwater age was used as a measure for evaluating circulation change between the existing condition and scenarios. This timescale measures the overall change in the transport processes of saltwater as channel depth changes [50]. A transect along the mainstem of the James River was selected to demonstrate the variation of transport processes after channel deepening.…”

Section: Change In Saltwater Age Along the Transectmentioning

confidence: 99%

A Modeling Study on the Influence of Sea-Level Rise and Channel Deepening on Estuarine Circulation and Dissolved Oxygen Levels in the Tidal James River, Virginia, USA

Shen

2020

JMSE

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The impact of channel deepening and sea-level rise on the environmental integrity of an estuary is investigated using a three-dimensional hydrodynamic-eutrophication model. The model results show that dissolved oxygen (DO) only experienced minor changes, even when the deep channel was deepened by 3 m in the mesohaline and polyhaline regions of the James River. We found that vertical stratification decreased DO aeration while the estuarine gravitational circulation increased bottom DO exchange. The interactions between these two processes play an important role in modulating DO. The minor change in DO due to channel deepening indicates that the James River is unique as compared with other estuaries. To understand the impact of the hydrodynamic changes on DO, both vertical and horizontal transport timescales represented by water age were used to quantify the changes in hydrodynamic conditions and DO variation, in addition to traditional measures of stratification and circulation. The model results showed that channel deepening led to an increase in both gravitational circulation strength and vertical stratification. Saltwater age decreased and vertical exchange time increased with increases in channel depth. However, these two physical processes can compensate each other, resulting in minor changes in DO. A comparison of the impact of a sea-level rise of 1.0 m with channel deepening scenarios was conducted. As the sea level rises, the vertical transport time decreases slightly while the strength of gravitational circulation weakens due to an increase in mean water depth. Consequently, DO in the estuary experiences a moderate decrease.

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Potential physical impacts of sea-level rise on the Pearl River Estuary, China

Cited by 56 publications

References 53 publications

Saltwater Intrusion in a Mediterranean Delta Under a Changing Climate

Saltwater Intrusion in a Mediterranean Delta Under a Changing Climate

Wave Effects on Sediment Transport and Entrapment in a Channel‐Shoal Estuary: The Pearl River Estuary in the Dry Winter Season

A Modeling Study on the Influence of Sea-Level Rise and Channel Deepening on Estuarine Circulation and Dissolved Oxygen Levels in the Tidal James River, Virginia, USA

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