Geographical Variation in Coastal Development

Davies, J. L.; Clayton, Keith

doi:10.2307/1796135

Cited by 82 publications

(14 citation statements)

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“…This indicates most pixels that experienced significant vegetation-based rates of change either experienced those at the p < 0.001 level for only one vegetation metric, or at the p < 0.01 and/or 0.05 levels for multiple metrics. Figure 5 shows the overall vegetation hot spot analysis, where the hot spot bins are represented by light orange (−1, −2, −3), dark orange (−4, −5, −6), and dark red (−7, −8, −9), respectively; while the cold spot bins are represented by light green (1, 2, 3), medium green (4,5,6), and dark green (7,8,9), respectively. Most of the hot spot areas (orange and red pixels, Figure 5) are concentrated within linear features at the northern reach of each Pea Island AOI or scattered throughout the southern portions of the AOIs.…”

Section: Hot Spot Analysis: Vegetation Metricsmentioning

confidence: 99%

“…Estimating vegetation characteristics (i.e., biomass) can be essential for monitoring and predicting wetland productivity, resilience, and ecosystem health [7,8]. Thus, rapidly quantifying vegetation dynamics across the dune profile (from the dune toe to beyond the more elevated and heavily vegetated primary dune) is an important aspect for understanding dune morphology and associated impacts from coastal processes [9].…”

Section: Introductionmentioning

confidence: 99%

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Multi-Temporal Trend Analysis of Coastal Vegetation Using Metrics Derived from Hyperspectral and LiDAR Data

et al. 2023

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Monitoring and modeling of coastal vegetation and wetland systems are considered major challenges, especially when considering environmental response to hazards, disturbances, and management activities. Remote sensing applications can provide alternatives and complementary approaches to the often costly and laborious field-based collection methods traditionally used for coastal ecosystem monitoring. New and improved sensors and data analysis techniques have become available, making remote sensing applications attractive for evaluation and potential use in monitoring coastal vegetation properties and ecosystem conditions and change. This study involves the extraction of vegetation metrics from airborne LiDAR (Light Detection and Ranging) and hyperspectral imagery (HSI) to quantify coastal dune vegetation characteristics and assesses landscape-level trends from those derived metrics. HSI- and LiDAR-derived elevation (digital elevation model) and vegetation metrics (canopy height model, leaf area index, and normalized difference vegetation index) were used in conjunction with per-pixel linear regression and hot spot analyses to evaluate hurricane-induced spatial and temporal changes in elevation and vegetation properties. These assessments showed areas with greatest decreases in vegetation metric values were associated with direct tropical storm energies and processes (i.e., overwashing events eroding beach and dune features), while those with the greatest increases in vegetation metric values were in areas where overwashed sediments were distributed. This study narrows existing gaps in dune vegetation data by advancing new methodologies to classify, quantify, and estimate critical coastal vegetation metrics. The tools and methods developed in this study will ultimately improve future estimates and predictions of nearshore dynamics and impacts from disturbance events.

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Section: Hot Spot Analysis: Vegetation Metricsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Multi-Temporal Trend Analysis of Coastal Vegetation Using Metrics Derived from Hyperspectral and LiDAR Data

et al. 2023

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“…In contrast to the extreme wave energy, the tidal regime off the Orange River mouth is semi‐diurnal with a spring tidal range of <2 m, making this a micro‐tidal coast (Davies, 1972). In this wave‐dominated setting, tidal currents have little significance and sediment dispersion along the present coastline and adjacent shelf are largely governed by wave‐induced currents (Branch & Griffiths, 1988; de Decker, 1988; Fawcetta et al ., 2008).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…The Atlantic coastline of south‐west Africa is recognized as the most energetic in the world (Hay & Brock, 1992), due to the persistence of waves driven by onshore‐directed, high‐energy winds (Davies, 1972). These strong south quadrant winds are dominant throughout the year, but are less pronounced in winter due to the increased occurrence of northerly wind reversals (Rogers, 1977; Tchernia, 1980; Corbett, 1989; Woodborne, 1991).…”

Section: Geological Backgroundmentioning

confidence: 99%

Anatomy of a diamondiferous gravel barrier spit at the palaeo‐Orange River mouth, south‐western Namibia

Spaggiari

Bordy

2023

Sedimentology

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The sedimentary facies architecture of a Plio-Pleistocene diamond-bearing gravel barrier spit within the palaeo-Orange River mouth in south-western Namibia has been revealed during onshore mining activities. Four sedimentary facies associations build this ancient coastal landform and have been interpreted, from a seaward to landward direction, as sediments in: (i) the foreshore, represented by an intertidal beach; (ii) a subtidal spit platform on which the spit developed; (iii) storm-constructed spit head recurves on the landward side of the spit; and (iv) an estuarine back-barrier. This sedimentary record reflects an evolving spit that grew in response to a combination of marine and fluvial processes in a wavedominated, high-energy coastal regime. Here, the southern Atlantic Ocean aggressively dispersed sediment delivered by a Plio-Pleistocene Orange River, ensuring that the fine-grained sediments were removed to allow only the gravel fraction to build up along the coastline. This extreme dispersal of sediment also precluded the construction of a classic delta; hence sediment storage offshore of the river mouth was limited and spit growth was dependent on the direct supply of river sediment. In response to the intermittent supply of sediment, spit growth and decay alternated during periods of sediment abundance and starvation, respectively. During positive sediment budget, the spit extended northward and cut off parts of the mainland to form an estuarine back-barrier. Foreshore and spit head progradation was sustained under these conditions, and formed a beach-ridge plain with a topographic expression of several coast-parallel ridges that curved at the spit head into the back-barrier. Spit extension and recurve development were controlled by a combination of high sediment supply, a vigorous longshore drift and powerful waves approaching from various directions. This Plio-Pleistocene coastal landform in Namibia offers a depositional model relevant to graveldominated barrier spits near river mouths along wave-dominated clastic coasts.

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“…The exchange of sediment between the dunes and beach might be balanced during overwash and aeolian processes (S. P. Leatherman, 1977). Secondary dunes, which result from continued aeolian processes, are generally located further inland (Davies, 1980). Despite being situated on eroding barriers, secondary dunes tend to be more stable and maintain their structural integrity in the face of low to moderate wave activity (Short, 1988).…”

mentioning

confidence: 99%

Laboratory Investigation of Hydrodynamic and Sand Dune Morphology Changes Under Wave Overwash

Liang,

Qu,

Lee

et al. 2023

JGR Oceans

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Since the field measurement of wave overwash is difficult to obtain during severe storms, a laboratory experiment is conducted to measure the time and space evolution of the overwash and beach profile over the sand dune continuously using high‐speed video image analysis for different wave conditions of irregular waves and solitary waves. Characteristics of the cross‐shore sediment transport and morphology change are discussed from the laboratory experiment data. The inflection point, which marks the shifting turn in dune crest movement during overwash, is determined by analyzing feature points in the variation of dune geometry. It is confirmed that the overwash water volume rate reaches a maximum value when the inflection point occurs. Additionally, the overwash water volume is found to be linearly related to the deposited sediment volume, and the dune erosion volume is proportional to wave energy flux during the overwash process. The presence of secondary dunes is found to significantly alleviate coast erosion during overwash and reduce shoreline retreat by more than 40%, regardless of the height of the secondary dune crest. Furthermore, the advances and limitations in overwash hydrodynamics are discussed. It is recommended that this continuous morphological change monitoring data be combined with a wave resolution model for detailed hydrodynamic simulations to further understand the overwash process.

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Geographical Variation in Coastal Development

Cited by 82 publications

References 0 publications

Multi-Temporal Trend Analysis of Coastal Vegetation Using Metrics Derived from Hyperspectral and LiDAR Data

Multi-Temporal Trend Analysis of Coastal Vegetation Using Metrics Derived from Hyperspectral and LiDAR Data

Anatomy of a diamondiferous gravel barrier spit at the palaeo‐Orange River mouth, south‐western Namibia

Laboratory Investigation of Hydrodynamic and Sand Dune Morphology Changes Under Wave Overwash

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