Storm Impact on Morphological Evolution of a Sandy Inlet

Hopkins, Julia; Elgar, Steve; Raubenheimer, Britt

doi:10.1029/2017jc013708

Cited by 16 publications

(4 citation statements)

References 34 publications

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“…The biggest changes (Figure 4c) happened after extreme storm events, for instance, the unusual storm event of 1 February 2014 with PSI = 18,279 m 2 .h ( Table 1). These results are consistent with other observational and modeling studies under storm conditions (e.g., in [3,50] and references therein). The maximum tidal current velocity values at Figueira da Foz inlet ranged from 0.8 to 1.2 m.s -1 for spring tides and from 0.4 to 0.7 m.s -1 for neap tides [51].…”

Section: Discussionsupporting

confidence: 92%

Assessment of Dredging Scenarios for a Tidal Inlet in a High-Energy Coast

Fernández-Fernández

Ferreira

Silva

et al. 2019

JMSE

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The high energetic wave climate of the North Atlantic Ocean causes important morphological changes at Figueira da Foz coastal system (W Portugal), which is comprised of sandy beaches and the Mondego estuary-inlet. The submerged sandbar at the inlet mouth is highly dynamic inducing short waves shoaling and breaking processes that can entail navigation problems towards the local harbor. Therefore, coastal dredging operations are performed to guarantee safe navigation. Nevertheless, these operations have a limited temporal effectiveness and require a high annual budget to be accomplished. The goal of this research is to seek long-life dredging alternatives using modeling tools (i.e., Delft3D model suite). Delft3D model is used to simulate the morphological evolution of five dredging scenarios during a three-month winter period under three wave climate scenarios. The bed level differences at the dredged area and at the inlet mouth for each scenario are analyzed in comparison with numerical solutions obtained in a reference scenario (i.e., no-dredging). Results highlight morphological changes at the dredged inlet and surrounding areas and their effectiveness in extending the operational lifetime of inlet dredged operations on dredging configuration and wave climate conditions. These findings are the basis for selecting the most suitable dredging scenario to this coastal region under current wave climate conditions.

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Section: Discussionsupporting

confidence: 92%

Assessment of Dredging Scenarios for a Tidal Inlet in a High-Energy Coast

Fernández-Fernández

Ferreira

Silva

et al. 2019

JMSE

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“…Process-based coastal area models have the potential to provide comprehensive information at multiple spatio-temporal scales allowing more detailed evaluation. To date such coastal morphodynamic models are generally able to adequately simulate morphological change due to concurrent tides, waves and currents for short to medium-term time scales; events of 3-4 years [10][11][12][13]. Prediction of the long-term dynamics of sandy interventions have however remained a major challenge for process-based models [14].…”

Section: Introductionmentioning

confidence: 99%

Morphodynamic Acceleration Techniques for Multi-Timescale Predictions of Complex Sandy Interventions

Luijendijk

Schipper

Ranasinghe

2019

JMSE

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Thirty one percent (31%) of the world’s coastline consists of sandy beaches and dunes that form a natural defense protecting the hinterland from flooding. A common measure to mitigate erosion along sandy beaches is the implementation of sand nourishments. The design and acceptance of such a mitigating measure require information on the expected evolution at time scales from storms to decades. Process-based morphodynamic models are increasingly applied, together with morphodynamic acceleration techniques, to obtain detailed information on this wide scale of ranges. This study shows that techniques for the acceleration of the morphological evolution can have a significant impact on the simulated evolution and dispersion of sandy interventions. A calibrated Delft3D model of the Sand Engine mega-nourishment is applied to compare different acceleration techniques, focusing on accuracy and computational times. Results show that acceleration techniques using representative (schematized) wave conditions are not capable of accurately reproducing the morphological response in the first two years. The best reproduction of the morphological behavior of the first five years is obtained by the brute force simulations. Applying input filtering and a compression factor provides similar accuracy yet with a factor five gain in computational cost. An attractive method for the medium to long time scales, which further reduces computational costs, is a method that uses representative wave conditions based on gross longshore transports, while showing similar results as the benchmark simulation. Erosional behavior is captured well in all considered techniques with variations in volumes of about 1 million m 3 after three decades. The spatio-temporal variability of the predicted alongshore and cross-shore distribution of the morphological evolution however have a strong dependency on the selected acceleration technique. A new technique, called ’brute force merged’, which incorporates the full variability of the wave climate, provides the optimal combination of phenomenological accuracy and computational efficiency (a factor of 20 faster than the benchmark brute force technique) at both the short and medium to long time scales. This approach, which combines realistic time series and the mormerge technique, provides an attractive and flexible method to efficiently predict the evolution of complex sandy interventions at time scales from hours to decades.

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“…Delft3D consists of Flow, Wave, and Morphology modules that can be coupled to simulate the processes of fluvial‐tidal‐wave hydrodynamics, sediment transport, and morphological changes (for details see Text S1 in Supporting Information ). It has been applied and validated in various environments (estuaries, coastal waters, inland rivers) over a wide range of timescales, such as long‐term, centennial, decadal, sub‐decadal, annual, sub‐annual, seasonal and event scales (e.g., Gelfenbaum et al., 2015; Hibma et al., 2003; Hopkins et al., 2018; Lesser et al., 2004; Luan et al., 2017; Luijendijk et al, 2017; Meselhe et al., 2016; van der Wegen & Roelvink, 2008; van der Wegen et al., 2008, van der Wegen, Jaffe, & Roelvink, 2011; G. Wu et al., 2023; Zhu & Wiberg, 2022; Zhu et al., 2017).…”

Section: Methodsmentioning

confidence: 99%

Reservoir Mud Releasing May Suboptimize Fluvial Sand Supply to Coastal Sediment Budget: Modeling the Impact of Shihmen Reservoir Case on Tamsui River Estuary

Hsueh,

Wu,

et al. 2024

Water Resources Research

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Regular release of sediment from reservoir has been increasingly adopted as a strategy for sustainable management. Here, we use a process‐based morphodynamic model to simulate the estuarine sediment dynamics impacted by turbidity current venting implemented by the Shihmen Reservoir during three typhoon events in 2008. Upon validation with the post‐event bathymetries, the model hindcasts reveal that mud releasing can be effective in mitigating reservoir siltation, yet may be a suboptimal strategy for alleviating coastal sediment deficit. A vast majority of the released muds were delivered through the estuary and exported to offshore by flood advection, wave dispersion, and tidal flushing. The flood‐driven sands, sourced mainly from downstream tributaries, were instead the major contributor to coastal sediment budget. However, mud mantling (covering and immobilizing sand deposits by the reservoir‐released muds) reduced sand availability and thus sand delivery to the coast. For the present case, 25% of the released muds were deposited along the way, presence of these mud covers reduced sand delivery by 15%, compared to a hypothetical scenario of clear‐water flood releases. The relative sand transport deficit is found to increase linearly with the degree of bed mud saturation, 1–D/R, with D/R the ratio of single‐event mud deposit to release. Given broad relevance to global reservoirs encountering the problems of siltation and coastal sediment deficit, our findings highlight that sustainable management needs to look beyond just a bulk amount of sediment, but it is critical to consider how different sediment fractions are interacting and impacted by human activities.

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Storm Impact on Morphological Evolution of a Sandy Inlet

Cited by 16 publications

References 34 publications

Assessment of Dredging Scenarios for a Tidal Inlet in a High-Energy Coast

Assessment of Dredging Scenarios for a Tidal Inlet in a High-Energy Coast

Morphodynamic Acceleration Techniques for Multi-Timescale Predictions of Complex Sandy Interventions

Reservoir Mud Releasing May Suboptimize Fluvial Sand Supply to Coastal Sediment Budget: Modeling the Impact of Shihmen Reservoir Case on Tamsui River Estuary

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