Determining Critical River Discharge as a Means to Provide Water Supply Security to the Changjiang River Estuary, China

Chen, Qing; Zhu, Jianrong; Lyu, Hanghang; Chen, Shenliang

doi:10.2112/jcoastres-d-18-00165.1

Cited by 10 publications

(16 citation statements)

References 20 publications

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“…The above simulated temporal variation processes in salinity at the water intakes of three reservoirs were reasonably close to the published studies Chen et al, 2019).…”

Section: Impacts On Water Resourcessupporting

confidence: 87%

Impacts of topography change on saltwater intrusion over the past decade in the Changjiang Estuary

Chen

Zhu

Lyu

et al. 2019

Estuarine, Coastal and Shelf Science

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Saltwater intrusion in estuaries is mainly controlled by tides and river discharge, as well as by topography and other factors. The Changjiang estuary has been seen a significant change in its topography from the data obtained in 2007 and 2017. In this study, a well-validated 3D numerical model was used to simulate and analyze the residual water and salt transport, water diversion ratio (WDR) in bifurcated channels and water resources in the Changjiang Estuary in 2007 and 2017. The comparisons of the model results showed that due to the North Branch becoming much shallower and narrower over the period from 2007 to 2017, the overall salinity in the North Branch decreased and the intensity of saltwater spillover (SSO) from the North Branch into the South Branch weakened. In the North Channel, the simulated residual or net transection water flux (NTWF) and WDR decreased during spring tides, resulting in increased saltwater intrusion. During neap tides, the saltwater intrusion was weakened despite the decreased NTWF and WDR because the water depth at the river mouth became shallower. The changes of topography during that period also resulted in changes of DWR, NTWF, salt transport across the tidal flats and dykes in the North Passage, South Passage and the South Channel, as well as overall dynamic mechanism. The results indicated that the salinity at the water intakes of the three reservoirs in the estuary slightly decreased, indicating that the time that reservoirs can take water from the estuary become longer in dry seasons. In the scenario of complete silt-up of the North Branch, the saltwater intrusion was weakened in the South Branch because of the disappearance of the SSO, which was favorable for the utilization of freshwater resources, but enhanced in the North Channel, North and South Passages. The overall influence from the topographic change over the period is that the saltwater intrusion is weakened in the North Branch, and enhanced during spring tides and weakened during neap tides in the North Channel, North and South Passages. Sediment accretion in the North Branch is favorable for utilization of freshwater resources.

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“…The above simulated temporal variation processes in salinity at the water intakes of three reservoirs were reasonably close to the published studies Chen et al, 2019).…”

Section: Impacts On Water Resourcessupporting

confidence: 87%

Impacts of topography change on saltwater intrusion over the past decade in the Changjiang Estuary

Chen

Zhu

Lyu

et al. 2019

Estuarine, Coastal and Shelf Science

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“…The prevailing monsoon climate results in a strong northerly wind of 5.5 m s −1 during winter and a southeasterly wind of 5.0 m s −1 during summer (Zhu et al, 2015). Saltwater intrusion in the Changjiang estuary is also mainly determined by river discharge and tides (Song and Mao, 2002;Gu et al, 2003;Shen et al, 2003;Luo and Chen, 2005;Qiu et al, 2012;Chen et al, 2019a) but is also influenced by wind (Xue et al, 2009;Li et al, 2012;Ding et al, 2017;Zhang et al, 2019) and topography (Li et al, 2014;Chen et al, 2019b). The impact of wind on saltwater intrusion has been studied but only with a climatic wind (Xue et al, 2009;Qiu et al, 2012;Chen et al, 2019a) and a strong northerly wind induced by ordinary cold fronts in winter lasting 1-2 d, which could cause a change in the observed salinity (Li et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Saltwater intrusion in the Changjiang estuary is also mainly determined by river discharge and tides (Song and Mao, 2002;Gu et al, 2003;Shen et al, 2003;Luo and Chen, 2005;Qiu et al, 2012;Chen et al, 2019a) but is also influenced by wind (Xue et al, 2009;Li et al, 2012;Ding et al, 2017;Zhang et al, 2019) and topography (Li et al, 2014;Chen et al, 2019b). The impact of wind on saltwater intrusion has been studied but only with a climatic wind (Xue et al, 2009;Qiu et al, 2012;Chen et al, 2019a) and a strong northerly wind induced by ordinary cold fronts in winter lasting 1-2 d, which could cause a change in the observed salinity (Li et al, 2012). Xue et al (2009) pointed out that a northerly wind tends to enhance the saltwater intrusion in the northern branch by reducing the seaward surface elevation gradient forcing.…”

Section: Introductionmentioning

confidence: 99%

Dynamic mechanism of an extremely severe saltwater intrusion in the Changjiang estuary in February 2014

Zhu¹,

Cheng²,

Li³

et al. 2020

Hydrol. Earth Syst. Sci.

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Abstract. Estuarine saltwater intrusions are mainly controlled by river discharge and tides. Unexpectedly, an extremely severe saltwater intrusion event occurred in February 2014 in the Changjiang estuary under normal river discharge conditions. This intrusion cut off the freshwater input for 23 d into the Qingcaosha reservoir, which is the largest estuarine reservoir in the world, creating a severe threat to water safety in Shanghai. No similar catastrophic saltwater intrusion has occurred since records of salinity in the estuary have been kept. During the event, a persistent and strong northerly wind existed, with a maximum speed of 17.6 m s−1, lasting 9 d and coinciding with a distinct water level rise. Our study demonstrates that the extremely severe saltwater intrusion was caused by this northerly wind, which drove substantial landward net water transport to form a horizontal estuarine circulation that flowed into the northern channel and out of the southern channel. This landward net water transport overpowered the seaward-flowing river runoff and transported a large volume of highly saline water into the northern channel. The mechanisms of this severe saltwater intrusion event, including the northerly wind, residual water level rise, landward water transport and resulting horizontal circulation, etc., were systematically investigated.

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“…The prevailing monsoon climate results in a stronger northerly wind of 5.5 m s -1 during winter and a southeasterly wind of 5.0 m s -1 during summer (Zhu et al, 2015). Saltwater intrusion in the Changjiang Estuary is also mainly determined by river discharge and tides (Song and Mao, 2002;Gu et al, 2003;Shen et al, 2003;Luo and Chen, 2005;Qiu et al 2012;Chen et al, 2019a) but is also influenced by wind (Xue et al, 2009;Li et al, 2012), and topography (Li et al, 2014;Chen et al, 2019b). The impact of wind on saltwater intrusion has been studied, but only with a climatological wind (Xue et al, 2009), and a strong northerly wind induced by ordinary cold fronts in winter lasting 1-2 days, which could cause a change in the observed salinity (Li et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Limited by reservoir capacity, long-lasting saltwater intrusion is extremely harmful (Chen et al, 2019a).…”

Section: Introductionmentioning

confidence: 99%

Dynamic mechanism of extremely severe saltwater intrusion in the Changjiang Estuary occurred in February 2014

Zhu

et al. 2020

Preprint

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Abstract. Estuarine saltwater intrusion is mainly controlled by river discharge and tide. Unexpectedly, an extremely severe saltwater intrusion event in February 2014 occurred in the Changjiang Estuary under normal river discharge conditions. It cut off the freshwater input for 23 days into the Qingcaosha Reservoir, which is the largest estuarine reservoir in the world, creating a severe threat to water safety in Shanghai. Such catastrophic saltwater intrusion has not occurred since recorded salinity in the estuary. During the event, a persistent and strong northerly wind existed, with a maximum speed of 16 m s−1, lasting ten days and coinciding with a distinct water level rise. Our study demonstrates that this extremely severe saltwater intrusion was caused by a persistent and strong northerly wind, which drove substantial landward Ekman transport to form a horizontal estuarine circulation that flowed into the North Channel and out of the South Channel. This process surpassed seaward runoff and brought very large amounts of highly saline water into the upper reaches in the North Channel. An ordinary cold front passing over the estuary cannot produce strong saltwater intrusion; only a strong northerly wind lasting 8 days can produce a severe saltwater intrusion in the Changjiang Estuary. The revealed dynamic mechanism is important to ensure safety of freshwater resource utilization in estuaries.

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Determining Critical River Discharge as a Means to Provide Water Supply Security to the Changjiang River Estuary, China

Cited by 10 publications

References 20 publications

Impacts of topography change on saltwater intrusion over the past decade in the Changjiang Estuary

Impacts of topography change on saltwater intrusion over the past decade in the Changjiang Estuary

Dynamic mechanism of an extremely severe saltwater intrusion in the Changjiang estuary in February 2014

Dynamic mechanism of extremely severe saltwater intrusion in the Changjiang Estuary occurred in February 2014

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