Sediment budget controls on foredune height: Comparing simulation model results with field data

Davidson‐Arnott, Robin; Hesp, Patrick A.; Ollerhead, Jeff; Walker, Ian J.; Bauer, Bernard O.; Delgado‐Fernández, Irene; Smyth, Thomas

doi:10.1002/esp.4354

Cited by 87 publications

(105 citation statements)

References 83 publications

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“…Storms are most often considered erosional events to dunes, but results here and from other studies (e.g. Hesp et al ., ; Davidson‐Arnott et al ., ) show that in some locations, strong winds during storms actually lead to significant dune growth, even when dry‐beach fetch is significantly reduced. For example, the strong extratropical event in February 2016 triggered one of the largest growth intervals at Nags Head (Figure e).…”

Section: Discussionmentioning

confidence: 99%

Terrestrial LiDAR monitoring of coastal foredune evolution in managed and unmanaged systems

Conery

Brodie

Spore

et al. 2020

Earth Surf Processes Landf

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Coastal dunes provide essential protection for infrastructure in developed regions, acting as the first line of defence against ocean‐side flooding. Quantifying dune erosion, growth and recovery from storms is critical from management, resiliency and engineering with nature perspectives. This study utilizes 22 months of high‐resolution terrestrial LiDAR (Riegl VZ‐2000) observations to investigate the impact of management, anthropogenic modifications and four named storms on dune morphological evolution along ~100 m of an open‐coast, recently nourished beach in Nags Head, NC. The influences of specific management strategies – such as fencing and plantings – were evaluated by comparing these to the morphologic response at an unmanaged control site at the USACE Field Research Facility (FRF) in Duck, NC (33 km to the north), which experienced similar environmental forcings. Various beach‐dune morphological parameters were extracted (e.g. backshore‐dune volume) and compared with aeolian and hydrodynamic forcing metrics between each survey interval. The results show that LiDAR is a useful tool for quantifying complex dune evolution over fine spatial and temporal scales. Under similar forcings, the managed dune grew 1.7 times faster than the unmanaged dune, due to a larger sediment supply and enhanced capture through fencing, plantings and walkovers. These factors at the managed site contributed to the welding of the incipient dune to the primary foredune over a short period of less than a year, which has been observed to take up to decades in natural systems. Storm events caused alongshore variable dune erosion primarily to the incipient dune, yet also caused significant accretion, particularly along the crest at the managed site, resulting in net dune growth. Traditional empirical Bagnold equations correlated with observed trends of backshore‐dune growth but overpredicted magnitudes. This is likely because these formulations do not encompass supply‐limiting factors and erosional processes. © 2019 John Wiley & Sons, Ltd.

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Section: Discussionmentioning

confidence: 99%

Terrestrial LiDAR monitoring of coastal foredune evolution in managed and unmanaged systems

Conery

Brodie

Spore

et al. 2020

Earth Surf Processes Landf

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“…Table 4 displays the drift potentials only (i.e., DP and RDP), and most prograded sites have high sediment transport potential (>18 v.u). This indicates that strong onshore (and alongshore) winds are important processes that transport sediment supplied to the beachface, into the foredunes, and contribute to dune building [30].…”

Section: Accreting Shorelinesmentioning

confidence: 99%

“…On a global scale, there are only a handful of studies that have looked at regional scale foredune evolution, especially over the intermediate (or engineering) timescale, which include the following: Areas of the USA, Canada, The Netherlands, and Italy [8,23,[27][28][29][30]. In NSW, there have been several localised investigations that have looked at foredune (or shoreline) evolution at this timescale, for example, at Bengello Beach (found in the far-south of NSW), a 45-year beach-foredune monitoring program is still being conducted, which has documented how those foredunes have eroded as a , which are strongly controlled by the degree of vegetation cover.…”

Section: Introductionmentioning

confidence: 99%

Interdecadal Foredune Changes along the Southeast Australian Coastline: 1942–2014

Doyle

Short

Ruggiero

et al. 2019

JMSE

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Foredunes are important features within coastal landscapes, yet there are relatively few medium to long-term studies on how they evolve and change over time. This study of Australia's New South Wales (NSW) foredunes has used 70 years of aerial photographs (or photogrammetry) and recent Light Detection and Ranging (LiDAR) datasets to assess multi-decadal fluctuations in foredune morphology. It was shown that over the past 70 years NSW foredunes have exhibited considerable spatial variation, ranging from accretion/aggradation to recession. Those sites that accreted predominantly extended seaward as new incipient dunes, gaining a maximum of 235 m 3 m −1 in sand volume over the study period (for the entire dune system). These sites were commonly found in the north of the state, within closed sediment compartments, and with strong onshore (and alongshore) wind climates present (increasing the potential for aeolian sand transport). Stable foredunes were those that remained within +/− 50 m 3 m −1 of their initial volume and managed to recover from the various storm impacts over the study period. The majority of these sites were found within the central to southern half of the state, behind embayed beaches, and within leaky sediment compartments, or those that have estuarine sinks. Finally, those foredunes in recession have retreated landwards and/or have reduced in height or width, and lost up to 437 m 3 m −1 of sand volume over the study period. There was no clear spatial trend for these sites; however, generally they were found in compartments that had unusual orientations, had disruptions in longshore drift/cross shore sand delivery (i.e., rocky reefs), or were being impacted by humans (i.e., the installation of river training walls, sand bypassing systems, or coastal management programs). This study has shown that NSW foredunes have undergone substantial recent changes and, by understanding their past history, will provide better insight into how they can be managed into the future.

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“…Modeling suggests that the height of purely aeolian foredunes could reflect a steady state condition associated with the local sediment supply regime and the presence/absence of stabilizing vegetation (Vinent & Moore, ). More recently, it has been shown that dune height is primarily a function of sediment supply, whereby vertical growth rate responds strictly to the size of the ridge (Davidson‐Arnott et al, ). For example, under constant input, the rate of elevation gain decreases for progressively larger ridges but never results in a steady state, allowing ridges to continue growing until stabilized inland of the active beach.…”

Section: Background: Development Of Beach and Foredune‐ridge Systemsmentioning

confidence: 99%

Reconstructing Coastal Sediment Budgets From Beach‐ and Foredune‐Ridge Morphology: A Coupled Field and Modeling Approach

Ciarletta

Shawler²,

Tenebruso

et al. 2019

JGR Earth Surface

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Preserved beach and foredune ridges may serve as proxies for coastal change, reflecting alterations in sea level, wave energy, or past sediment fluxes. In particular, time‐varying shoreface sediment budgets have been inferred from the relative size of foredune ridges through application of radiocarbon and optically stimulated luminescence dating to these systems over the last decades. However, geochronological control requires extensive field investigation and analysis. Purely field‐based studies might also overlook relationships between the mechanics of sediment delivery to the shoreface and foredune ridges, missing insights about sensitivity to changes in sediment budget. We therefore propose a simple geomorphic model of beach/foredune‐ridge and swale morphology to quantify the magnitude of changes in cross‐shore sediment budget, employing field measurements of ridge volume, ridge spacing, elevation, and shoreline progradation. Model behaviors are constrained by the partitioning of sediment fluxes to the shoreface and foredune ridge and can be used to reproduce several cross‐shore patterns observed in nature. These include regularly spaced ridges (“washboards”), large singular ridges, and wide swales with poorly developed ridges. We evaluate our model against well‐preserved ridge and swale systems at two sites along the Virginia Eastern Shore (USA): Fishing Point, for which historical records provide a detailed history of shoreline progradation and ridge growth, and Parramore Island, for which a relatively more complex morphology developed over a poorly constrained period of prehistoric growth. Our results suggest this new model could be used to infer the sensitivity of field sites across the globe to variations in sediment delivery.

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Sediment budget controls on foredune height: Comparing simulation model results with field data

Cited by 87 publications

References 83 publications

Terrestrial LiDAR monitoring of coastal foredune evolution in managed and unmanaged systems

Terrestrial LiDAR monitoring of coastal foredune evolution in managed and unmanaged systems

Interdecadal Foredune Changes along the Southeast Australian Coastline: 1942–2014

Reconstructing Coastal Sediment Budgets From Beach‐ and Foredune‐Ridge Morphology: A Coupled Field and Modeling Approach

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