Divergence of Sediment Fluxes Triggered by Sea‐Level Rise Will Reshape Coastal Bays

Zhang, Xiaohe; Leonardi, Nicoletta; Donatelli, Carmine; Fagherazzi, Sergio

doi:10.1029/2020gl087862

Cited by 14 publications

(8 citation statements)

References 64 publications

(79 reference statements)

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“…SLR is likely to accelerate in the coming century, adding another 0.28–1.01 m till 2100 (Chen et al., 2017; IPCC, 2021). A worldwide concern is that accretion of coastal tidal flats (mainly the intertidal zones) and salt marshes may not be able to keep pace with an accelerating SLR rate (Best et al., 2018; Zhang et al., 2020), resulting in coastal erosion and shoreline retreat, drowning of salt marshes and habitats, and increased flood risk (Craft et al., 2009; Kirwan & Megonigal, 2013; Lovelock et al., 2015; Valiela et al., 2018). Land subsidence and a decline in river‐borne sediment supply may further exacerbate coastal erosion and wetland losses (Syvitski et al., 2009).…”

Section: Introductionmentioning

confidence: 99%

Reclamation of Tidal Flats Within Tidal Basins Alters Centennial Morphodynamic Adaptation to Sea‐Level Rise

Guo

Zhu

et al. 2022

JGR Earth Surface

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Coastal wetlands provide important habitats that host valuable ecosystems. Currently they are facing increasing pressure from climate change and sea-level rise (SLR). The global SLR has risen by 0.2 ± 0.05 m between 1901 and 2018, with a rate of 3.7 ± 0.5 mm yr −1 in the 2006-2018 periods (IPCC, 2021). SLR is likely to accelerate in the coming century, adding another 0.28-1.01 m till 2100 (Chen et al., 2017;IPCC, 2021). A worldwide concern is that accretion of coastal tidal flats (mainly the intertidal zones) and salt marshes may not be able to keep pace with an accelerating SLR rate (

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Section: Introductionmentioning

confidence: 99%

Reclamation of Tidal Flats Within Tidal Basins Alters Centennial Morphodynamic Adaptation to Sea‐Level Rise

Guo

Zhu

et al. 2022

JGR Earth Surface

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“…Coastal models are generally calibrated with few tidal or velocity gauges because of the high cost of field observations (Zhang et al., 2020). In our study domain, 18 water level stations cover not only the main channel (WLO), but also the complex creeks network, well capturing the delay in tidal propagation and the flow attenuation over the entire system.…”

Section: Discussionmentioning

confidence: 99%

“…Coastal wetlands are natural buffer zones between land and ocean that provide protection from rising seas and storm surges (Fagherazzi et al., 2012, 2020; FitzGerald & Hughes, 2019; Schuersch et al., 2018). Sediment is essential for wetlands, because it promotes accretion that counteracts sea level rise (Donatelli et al., 2018; Ganju et al., 2017; Kirwan et al., 2016; Morris et al., 2002; Zhang et al., 2020). Unfortunately, as results of sediment starvation, loss of these valuable ecosystems is increasing worldwide.…”

Section: Introductionmentioning

confidence: 99%

Improving Channel Hydrological Connectivity in Coastal Hydrodynamic Models With Remotely Sensed Channel Networks

et al. 2022

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Coastal wetlands are nourished by rivers and periodical tidal flows through complex, interconnected channels.However, in hydrodynamic models, channel dimensions with respect to model grid size and uncertainties in topography preclude the correct propagation of tidal and riverine signals. It is therefore crucial to enhance channel geomorphic connectivity and simplify sub-channel features based on remotely-sensed networks for practical computational applications. Here, we utilize channel networks derived from diverse remote sensing imagery as a baseline to build a ~10 m resolution hydrodynamic model that covers the Wax Lake Delta and adjacent wetlands (~ 360 km 2 ) in coastal Louisiana, USA. In this richly-gauged system, intensive calibrations are conducted with 18 synchronous field-observations of water levels taken in 2016, and discharge data taken in 2021. We modify channel geometry, targeting realism in channel connectivity. The results show that a minimum channel depth of 2 m and a width of four grid elements (approximatively 40m) are required to enable a realistic tidal propagation in wetland channels. The optimal depth for tidal propagation can be determined by a simplified cost function method that evaluates the competition between flow travel time and alteration of the volume of the channels. The integration of high spatial-resolution models and remote sensing imagery provides a general framework to improve models performance in salt marshes, mangroves, deltaic wetlands, and tidal flats.

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“…At the same time, the beach serves as a natural barrier, a soft defense compared with human-made hard structures, to protect the coastal hinterland against flooding and extreme storm surges using wave energy dissipation (Rijn, 2009(Rijn, , 2010Slobbe et al, 2013;Stive et al, 2013). Hence, more and more concerns have been revealed on the mechanism of beach bed level changes since the twentieth century in the context of the higher frequency and greater intensity of extreme hydrological events (Vellinga, 1982;Rijn, 2011;Li et al, 2014;Masselink and Heteren, 2014;Hu et al, 2015) coupled with global sea-level rise (Nerem et al, 2018;Zhang et al, 2020), especially for low-lying coastal and island countries (Nicholls and Cazenave, 2010;Stive et al, 2013;Pucino et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

ADV-Based Investigation on Bed Level Changes Over a Meso-Macro Tidal Beach

et al. 2021

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Beach intra-tidal bed level changes are of significance to coastal protection amid global climate changes. However, due to the limitation of instruments and the disturbance induced by wave motions superimposed on water levels, it was difficult to detect the high-frequency oscillation of the submerged beach bed level. In this study, an observation, lasting for 12 days and covering the middle tide to the following spring tide, was conducted on a meso-macro tidal beach, Yintan Beach, to simultaneously detect the characteristics and influence mechanism of bed level changes at intra-tidal and tidal cycle scales. The collected data included water depth, suspended sediment concentration (SSC), waves, high-frequency three-dimensional (3-D) velocity, and the distance of the seabed to the acoustic Doppler velocimeter (ADV) probe, which were measured by an optical backscatter sensor, two Tide & Wave Recorder-2050s, and an ADV, respectively. The results showed that the tidal cycle-averaged bed level decreased by 58.8 mm, increased by 12.6 mm, and increased by 28.9 mm during neap, middle, and spring tides in succession, respectively, compared with the preceding tidal regimes. The net erosion mainly resulted from large incident wave heights and the consequent strong offshore-directed sediment transport induced by undertows. Moreover, the variations in the bed level were more prominent during a neap to middle tides than during middle to spring tides, which were jointly caused by the wave-breaking probability regulated by water depth and the relative residence times of shoaling wave, breaker, and surf zones that were determined by relative tidal range. In terms of the intra-tidal bed level, it displayed an intra-tidal tendency of increase during floods and decrease during ebb tides, i.e., the intra-tidal bed level changes were controlled by water depth, which modulated the effects of waves on sediment resuspension and vertical sediment exchange. To be specific, waves and SSC were responsible for the intra-tidal bed level changes under low-energy wave conditions, while mean current and bedform exerted important influences on the variations of the intra-tidal bed level under moderate wave conditions, which broke the foregoing interrelation between bed level, waves, and SSC. This study, therefore, emphasizes the usage of ADV measurement to investigate bed level changes in sandy coasts.

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Divergence of Sediment Fluxes Triggered by Sea‐Level Rise Will Reshape Coastal Bays

Cited by 14 publications

References 64 publications

Reclamation of Tidal Flats Within Tidal Basins Alters Centennial Morphodynamic Adaptation to Sea‐Level Rise

Reclamation of Tidal Flats Within Tidal Basins Alters Centennial Morphodynamic Adaptation to Sea‐Level Rise

Improving Channel Hydrological Connectivity in Coastal Hydrodynamic Models With Remotely Sensed Channel Networks

ADV-Based Investigation on Bed Level Changes Over a Meso-Macro Tidal Beach

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