scholarly journals Storm-induced sediment supply to coastal dunes on sand flats

2020 ◽  
Vol 8 (2) ◽  
pp. 335-350 ◽  
Author(s):  
Filipe Galiforni-Silva ◽  
Kathelijne M. Wijnberg ◽  
Suzanne J. M. H. Hulscher
Keyword(s):  
Numerical Model ◽  
Storm Surge ◽  
Storm Surges ◽  
Coastal Dunes ◽  
Sediment Supply ◽  
Aeolian Transport ◽  
Sand Flat ◽  
Sediment Transfer ◽  
Sand Flats

Abstract. Growth of coastal dunes requires a marine supply of sediment. Processes that control the sediment transfer between the subtidal and the supratidal zone are not fully understood, especially in sand flats close to inlets. It is hypothesised that storm surge events induce sediment deposition on sand flats, providing fresh material for aeolian transport and dune growth. The objective of this study is to identify which processes cause deposition on the sand flat during storm surge conditions and discuss the relationship between the supratidal deposition and sediment supply to the dunes. We use the island of Texel (NL) as a case study, of which multiannual topographic and hydrographic datasets are available. Additionally, we use the numerical model XBeach to simulate the most frequent storm surge events for the area. Results show that supratidal shore-parallel deposition of sand occurs in both the numerical model and the topographic data. The amount of sand deposited is directly proportional to surge level and can account for more than a quarter of the volume deposited at the dunes yearly. Furthermore, storm surges are also capable of remobilising the top layer of sediment of the sand flat, making fresh sediment available for aeolian transport. Therefore, in a sand flat setting, storm surges have the potential of reworking significant amounts of sand for aeolian transport in periods after the storm and as such can also play a constructive role in coastal dune development.

scholarly journals Storm-induced sediment supply to coastal dunes on sand flats

2019 ◽  
Author(s):  
Filipe Galiforni Silva ◽  
Kathelijne M. Wijnberg ◽  
Suzanne J. M. H. Hulscher
Keyword(s):  
Numerical Model ◽  
Storm Surge ◽  
Storm Surges ◽  
Coastal Dunes ◽  
Sediment Supply ◽  
Data Sets ◽  
Aeolian Transport ◽  
Tidal Zone ◽  
Sand Flat ◽  
Sand Flats

Abstract. Marine supply of sand can control the development and morphology of coastal dunes. However, processes that control the sediment transfer between sub-tidal and the supra-tidal zone are not fully understood, especially in coastal settings such as sand-flats close to inlets. It is hypothesised that storm surge events induce sediment deposition on sand-flats, so that this may influence dune development significantly. Therefore, the objective of this study is to identify which processes causes deposition on the sand-flat during storm-surge conditions and discuss the relation between the supra-tidal deposition and sediment supply to the dunes. We use the island of Texel as a case study, on which multi-annual topographic and hydrographic data sets are available. Additionally, we use the numerical model XBeach to simulate the most frequent storm surge events for the area. Results show that a supra-tidal shore-parallel deposition of sand occurs in both the numerical model and the data. The amount of sand deposition is directly proportional to surge level, and can account for more than half of the volume deposited at the dunes on a yearly basis. Furthermore, storms are also capable of remobilising the top layer of sediment of the sand-flat, making fresh sediment available for aeolian transport. Therefore, in a sand-flat setting, storm surges have the potential of adding significant amounts of sand for aeolian transport in periods after the storm, suggesting that storms play a significant role in the onshore sand supply between sub-tidal and subaerial zones in those areas.

scholarly journals Storm-induced sediment supply to coastal dunes on sand flats

2020 ◽  
Author(s):  
Filipe Galiforni-Silva ◽  
Kathelijne M. Wijnberg ◽  
Suzanne J. M. H. Hulscher
Keyword(s):  
Numerical Model ◽  
Storm Surge ◽  
Storm Surges ◽  
Coastal Dunes ◽  
Sediment Supply ◽  
Data Sets ◽  
Aeolian Transport ◽  
Tidal Zone ◽  
Sand Flat ◽  
Sand Flats

Abstract. Growth of coastal dunes requires a marine supply of sediment. Processes that control the sediment transfer between the sub-tidal and the supra-tidal zone are not fully understood, especially in sand flats close to inlets. It is hypothesised that storm surge events induce sediment deposition on sand flats, providing fresh material for aeolian transport and dune growth. The objective of this study is to identify which processes cause deposition on the sand flat during storm surge conditions and discuss the relationship between the supra-tidal deposition and sediment supply to the dunes. We use the island of Texel as a case study, of which multi-annual topographic and hydrographic data sets are available. Additionally, we use the numerical model XBeach to simulate the most frequent storm surge events for the area. Results show that supra-tidal shore-parallel deposition of sand occurs in both the numerical model and the topographic data. The amount of sand deposition is directly proportional to surge level and can account for more than a quarter of the volume deposited at the dunes yearly. Furthermore, storm surges are also capable of remobilising the top layer of sediment of the sand flat, making fresh sediment available for aeolian transport. Therefore, in a sand flat setting, storm surges have the potential of reworking significant amounts of sand for aeolian transport in periods after the storm, and as such can also play a constructive role in coastal dune development.

scholarly journals On the Relation between Beach-Dune Dynamics and Shoal Attachment Processes: A Case Study in Terschelling (NL)

2020 ◽  
Vol 8 (7) ◽  
pp. 541
Author(s):  
Filipe Galiforni-Silva ◽  
Kathelijne M. Wijnberg ◽  
Suzanne J. M. H. Hulscher
Keyword(s):  
Morphological Evolution ◽  
Coastal Dunes ◽  
Annual Data ◽  
Aeolian Transport ◽  
Cellular Automata Model ◽  
Beach Width ◽  
Ebb Tidal Delta ◽  
Dune Dynamics

Inlet-driven processes are capable of modifying the adjacent shoreline. However, few studies have attempted to understand how these changes affect coastal dunes. The present study aims to understand how shoreline changes induced by shoal attachment affect coastal dunes. A barrier island in the Netherlands is used as a case study. Both bathymetric and topographic annual data were analysed, together with the application of a cellular automata model for dune development. The objective of the model is to explore idealised scenarios of inlet-driven shoreline movements. With the model, ten different scenarios were examined regarding beach width increase and rate of alongshore spreading of the shoal. Field data showed that, for the case study, dune volume and shoal attachments could not be directly linked. Instead, rates of dune volume change differed significantly only due to long-term ebb-tidal delta evolution. Such morphological evolution oriented the beach towards the main wind direction, increasing overall aeolian transport potential. Modelling results showed that shoals significantly increased dune volumes only on three out of ten scenarios. This suggests that beach width increase, and rate of alongshore sediment spreading, determine whether the shoal will influence dune growth. Therefore, within the studied time-scale, local rates of dune growth are only increased if shoals are capable of increasing the beach width significantly and persistently.

scholarly journals Simulation of storm surge inundation under different typhoon intensity scenarios: case study of Pingyang County, China

2020 ◽  
Vol 20 (10) ◽  
pp. 2777-2790
Author(s):  
Xianwu Shi ◽  
Pubing Yu ◽  
Zhixing Guo ◽  
Zhilin Sun ◽  
Fuyuan Chen ◽  
...  
Keyword(s):  
Storm Surge ◽  
Water Depth ◽  
Storm Surges ◽  
Economic Losses ◽  
Astronomical Tide ◽  
Evacuation Plans ◽  
Typhoon Intensity ◽  
Typhoon Tracks ◽  
The Impact

Abstract. China is one of the countries that is most seriously affected by storm surges. In recent years, storm surges in coastal areas of China have caused huge economic losses and a large number of human casualties. Knowledge of the inundation range and water depth of storm surges under different typhoon intensities could assist predisaster risk assessment and making evacuation plans, as well as provide decision support for responding to storm surges. Taking Pingyang County in Zhejiang Province as a case study area, parameters including typhoon tracks, radius of maximum wind speed, astronomical tide, and upstream flood runoff were determined for different typhoon intensities. Numerical simulations were conducted using these parameters to investigate the inundation range and water depth distribution of storm surges in Pingyang County considering the impact of seawall collapse under five different intensity scenarios (corresponding to minimum central pressure values equal to 915, 925, 935, 945, and 965 hPa). The inundated area ranged from 103.51 to 233.16 km2 for the most intense typhoon. The proposed method could be easily adopted in various coastal counties and serves as an effective tool for decision-making in storm surge disaster risk reduction practices.

scholarly journals Evolution of Storm Surges over the Little Ice Age Indicated by Aeolian Sand Records on the Coast of the Beibu Gulf, China

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1941
Author(s):  
Zhi Chen ◽  
Baosheng Li ◽  
Fengnian Wang ◽  
Shuhuan Du ◽  
Dongfeng Niu ◽  
...  
Keyword(s):  
Grain Size ◽  
Storm Surge ◽  
Little Ice Age ◽  
Storm Surges ◽  
Coastal Dunes ◽  
Ice Age ◽  
Heavy Minerals ◽  
Sunspot Activity ◽  
Beibu Gulf ◽  
High Maturity

The Wutou section, hereinafter referred to as “WTS”, lies in Jiangping, Guangxi Province, China (21°32′8.25″ N, 108°06′59.9″ E; thickness of 246 cm) and consists of fluvial-lacustrine facies and dune sands of the Late Holocene. This study reconstructed the evolution of storm surges along the coast of the Beibu Gulf, Guangxi over the Little Ice Age, based on three accelerator mass spectrometry (AMS)-14C, optically stimulated luminescence (OSL) dating ages, and the analyses of grain size and heavy minerals. The analysis results indicated that the storm sediments interspersed among aeolian sands, lagoon facies, and weak soil display a coarse mean grain size and poor sorting. The storm sediments also show high maturity of heavy minerals and low stability resulting from rapid accumulation due to storm surges originating from the land-facing side of the coastal dunes. Records of seven peak storm surge periods were recorded in the WTS over the past millennium and mainly occurred after 1400 AD, i.e., during the Little Ice Age. The peaks in storm surges, including the 14Paleostrom deposit (hereinafter referred to as “Pd”) (1425–1470AD), 10Pd (1655–1690AD), 6Pd (1790–1820AD), and 4Pd (1850–1885AD) approximately corresponded with the periods of minimum sunspot activity, suggesting that the periods of storm surge peaks revealed by the WTS were probably regulated to a great extent by solar activity.

Storm Surge Estimation Along Tokyo Bay Based on a Simple Stochastic Approach

2018 ◽  
Author(s):  
Rikito Hisamatsu ◽  
Sooyoul Kim ◽  
Shigeru Tabeta
Keyword(s):  
Numerical Model ◽  
Storm Surge ◽  
Return Period ◽  
Empirical Formula ◽  
Stochastic Analysis ◽  
Storm Surges ◽  
Stochastic Approach ◽  
Insurance Companies ◽  
Tokyo Bay ◽  
Risk Transfer

In recent years, refinement of stochastic storm surge estimation is essential for risk management in insurance industries because the Japanese government promotes flood risk transfer to insurance companies. Insurance systems may reach peak risk when storm surge damage occurs; however, there are only a few studies on the stochastic analysis of storm surges. This paper presents the stochastic evaluation of storm surges in Tokyo Bay. First, storm surges are assessed using two methods of an empirical formula and a numerical model. Then, the return period of storm surges is stochastically evaluated. It is found that an empirical formula underestimates the surge level in comparison to the numerical model. Based on the results of numerical model, the return period of a storm surge is proposed in Tokyo Bay.

Water movement and the simulation of storm surges in the Firth of Clyde

1986 ◽  
Vol 90 ◽  
pp. 85-96
Author(s):  
John M. Townson ◽  
Richard H. F. Collar
Keyword(s):  
Numerical Model ◽  
Storm Surge ◽  
General Circulation ◽  
Water Movement ◽  
Storm Surges ◽  
Equation Of Motion ◽  
Relative Importance

SynopsisThe basic mechanisms governing the general circulation of water in the Firth of Clyde are reviewed with particular reference to their changing relative importance throughout the system, this including the inner estuary. Attention is then focused on the effect of storm surge. A numerical model for the depth-integrated equation of motion is applied to the surges recorded in 1972 and 1979. The proportion of surge generated within the outer firth is thereby assessed.

scholarly journals Controls on submarine canyon connection to the shoreline: a numerical modelling approach

2021 ◽  
Author(s):  
Euan Soutter ◽  
Ian Kane ◽  
David Hodgson ◽  
Stephen Flint
Keyword(s):  
Numerical Model ◽  
Numerical Models ◽  
Submarine Canyon ◽  
Sediment Supply ◽  
Exact Nature ◽  
Submarine Canyons ◽  
Empirical Relationships ◽  
Sediment Transfer ◽  
Sediment Export ◽  
Modelling Approach

Submarine canyons with heads located close to shorelines, known as shore-connected canyons, provide a focussed pathway for basinward sediment transport. Placing greater constraints on the key parameters that control the formation of shore-connected canyons can help us predict the efficiency of sediment export to deep-water under different environmental conditions and through time. Using a numerical model incorporating geomorphic principles, we show that shore-connected canyons are most active when fluvial discharge is high, the continental shelf is steep and narrow, and the magnitude of relative sea-level change is high. The numerical model reproduces observed bathymetric distributions of shore-connected submarine canyons, indicating that the empirical relationships underlying these numerical models are accurate descriptions of shore-connected canyon formation in nature. Our study provides constraints on the key quantifiable parameters controlling shore-connected submarine canyon formation and maintenance, such as fluvial discharge and basin physiography, allowing for more accurate predictions of the efficiency and timing of sediment transfer to the deep sea under different conditions. The model results suggest that; 1) submarine canyons may form frequently on the slope due to submarine processes, but subaerial processes control which submarine canyons are most likely to connect to the shoreline, 2) margin physiography and sediment supply are more influential in driving submarine canyon incision across the shelf and sediment transfer than the exact nature of the gravity flow triggering mechanism, and 3) the stratigraphic records of shore-connected submarine canyons and fans are more influenced by onshore climate and tectonics than eustasy.

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