Articoli di riviste: "Dune morphodynamics"

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Courrech du Pont, Sylvain. "Dune morphodynamics". Comptes Rendus Physique 16, n. 1 (gennaio 2015): 118–38. http://dx.doi.org/10.1016/j.crhy.2015.02.002.

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Naqshband, Suleyman, Bas Wullems, Timo de Ruijsscher e Ton Hoitink. "Experimental investigation of low-angle dune morphodynamics". E3S Web of Conferences 40 (2018): 02056. http://dx.doi.org/10.1051/e3sconf/20184002056.

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Dunes commonly dominate the bed of sandy rivers and they are of central importance in predicting flow resistance and water levels. In the present study, we show that by using light-weight polystyrene particles as substrate in a laboratory setting, promising morphodynamic similarity is obtained between dunes in shallow flow (flume) and deep flow (field) conditions. In particular, results from our flume experiments show that dune lee-side angles, which are crucial in turbulence production and energy dissipation, better approximate dune lee-side angles observed in natural channels. Furthermore, dune height evolution towards upper stage plane bed observed in the present experimental study, closely follows dune height evolution as observed in world’s large rivers.

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Hoonhout, Bas, e Jaap Van Thiel de Vries. "MODELLING DUNE EROSION, OVERWASH AND INUNDATION OF BARRIER ISLANDS". Coastal Engineering Proceedings 1, n. 33 (25 ottobre 2012): 30. http://dx.doi.org/10.9753/icce.v33.sediment.30.

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Physical model experiments are performed at Deltares to investigate the morphological response of barrier islands on extreme storm events. The experiments included dune erosion, overwash and inundation regimes. Extensive measurement techniques made detailed comparison with numerical models possible. This paper describes the comparison between the physical model results and the numerical morphodynamic model XBeach. It appeared that XBeach simulates the main characteristics in hydro- and morphodynamics at profiles with shallow foreshores, which are characteristic for barrier islands, well. However, the absolute results of especially the overwash experiments still do not agree with the measurements. It is expected that several generic issues regarding small-scale physical model experiments are of influence here. Nevertheless, calibration of the XBeach model seems to be necessary for shallow profiles. Especially the calibration of the wave characteristics on the shallow foreshore, related to the morphodynamics is far from trivial.

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D’Alessandro, Felice, Giuseppe Roberto Tomasicchio e Ferdinando Frega. "Beach-Dune System Morphodynamics". Journal of Marine Science and Engineering 10, n. 6 (10 giugno 2022): 802. http://dx.doi.org/10.3390/jmse10060802.

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Coastal dunes are known for their functions in ecological systems in addition to their aesthetic qualities, providing a highly valuable and unique habitat of due to their biodiversity of flora and fauna [...]

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D’Alessandro, Felice, Giuseppe Roberto Tomasicchio, Ferdinando Frega, Elisa Leone, Antonio Francone, Daniela Pantusa, Giuseppe Barbaro e Giandomenico Foti. "Beach–Dune System Morphodynamics". Journal of Marine Science and Engineering 10, n. 5 (5 maggio 2022): 627. http://dx.doi.org/10.3390/jmse10050627.

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Beach–dune system morphodynamics is probably one of the most classical coastal engineering problems. While the topic has been studied extensively and literature is plentiful of considerable research contributions, from the authors’ knowledge the subject is still challenging for coastal and environmental sciences. As a part of the Special Issue entitled “Beach–dune system morphodynamics” of this Journal, the present paper reviews traditional issues and design advances building bridges between potential risks and adaptation measures. The benefits of nature-based and hybrid solutions and the need for multidisciplinary studies and approaches to promote sustainable and resilient conservation of the coastal environment are emphasized. Considering the importance and complexity of the subject, this work cannot be fully complete. It is limited to providing a general overview and outlining some important directions intending to serve as a springboard for further research in the field of beach–dune system morphodynamics.

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Darke, Ian B., Ian J. Walker e Patrick A. Hesp. "Beach-dune sediment budgets and dune morphodynamics following coastal dune restoration, Wickaninnish Dunes, Canada". Earth Surface Processes and Landforms 41, n. 10 (8 marzo 2016): 1370–85. http://dx.doi.org/10.1002/esp.3910.

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Wilson, Kat, e David Mohrig. "Signatures of Pleistocene Marine Transgression Preserved in Lithified Coastal Dune Morphology of The Bahamas". Geosciences 13, n. 12 (28 novembre 2023): 367. http://dx.doi.org/10.3390/geosciences13120367.

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The morphology of some lithified wind-blown, carbonate dunes in The Bahamas preserves the signature of erosion from paleo-marine processes: wave-induced swash, scarping, and longshore transport. Digital elevation models were used to distinguish between two dune morphotypes—those disconnected versus connected to beach processes. Dune sinuosity and upwind slope were quantified and used to interpret which dunes remained beach-attached and subject to marine erosion and processes versus dunes that became disconnected from the shoreline via inland migration or shoreline regression. Disconnected dunes possess low slopes over stoss surfaces with sinuous planforms mimicking their crestlines. Beach-connected foredunes preserve steep, kilometers-long linear upwind faces, which are interpreted to be signatures of beach-dune morphodynamics. Foredune morphology serves as a proxy for shoreline position during past sea-level high-stands, while the basal elevations of their stoss dune toes provide an upper limit on the beach and adjacent sea level. A growing library of digital topography will allow for this tool to be used to interpret global paleo-shoreline positions through time and space.

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Bastos, Ana Pestana, Rui Taborda, César Andrade, Cristina Ponte Lira e Ana Nobre Silva. "Short-Term Foredune Dynamics in Response to Invasive Vegetation Control Actions". Remote Sensing 16, n. 9 (23 aprile 2024): 1487. http://dx.doi.org/10.3390/rs16091487.

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Efforts to control the spread of invasive alien species (IAS) in coastal dunes are essential to protect biodiversity and maintain the integrity of the ecosystem. However, the timing and extent of these control measures often do not consider their potential impact on dune morphodynamics. This study investigated how IAS control measures can affect sand dune mobility. Research involved monitoring short-term morphological and vegetation changes using close-range remote sensing along with historical wind data. Findings revealed that changes in vegetation cover significantly impacted dune system evolution, notably increasing sand mobility when IAS vegetation was removed. Considering the seasonal wind regime, dominated by offshore winds in the summer, removing vegetation during this period can promote seaward sediment transport, potentially resulting in sediment loss to the beach. These findings highlight the importance of understanding sediment mobility patterns when planning vegetation control actions within dune restoration strategies.

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Maximiliano-Cordova, Carmelo, Rodolfo Silva, Edgar Mendoza, Valeria Chávez, M. Luisa Martínez e Rusty A. Feagin. "Morphological Performance of Vegetated and Non-Vegetated Coastal Dunes with Rocky and Geotextile Tube Cores under Storm Conditions". Journal of Marine Science and Engineering 11, n. 11 (28 ottobre 2023): 2061. http://dx.doi.org/10.3390/jmse11112061.

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Coastal dune restoration projects are increasingly seen as a means of protecting the coast against storms, especially with the use of natural (plants), artificial (geotextile tube cores) and hybrid (plants and geotextile tube) elements. As geotextile tube cores have been found to negatively affect dune and beach natural morphodynamics, rocky cores are thus seen as a potential alternative. We carried out laboratory experiments to compare the performance of dunes with rocky cores, geotextile cores, and both types when coupled with planted vegetation. We investigated these elements in the context of scaled mild, moderate, and intense storm conditions. The results showed that dunes with either type of core lost more sand than dunes without cores. The addition of plants generally reduced the erosion across the various options, but most strongly for rocky cores under mild and moderate storm conditions. We also found that dunes with a high density of plants were best for intense conditions. Overall, the use of rocky dune cores, when coupled with plants, is the most suitable and sustainable alternative option in hybrid engineering projects.

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Duo, Enrico, Stefano Fabbri, Edoardo Grottoli e Paolo Ciavola. "Uncertainty of Drone-Derived DEMs and Significance of Detected Morphodynamics in Artificially Scraped Dunes". Remote Sensing 13, n. 9 (7 maggio 2021): 1823. http://dx.doi.org/10.3390/rs13091823.

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This work capitalises on the morphodynamic study of a scraped artificial dune built on the sandy beach of Porto Garibaldi (Comacchio, Italy) as a barrier to protect the touristic facilities from sea storms during the winter season and contributes to understanding of the role of elevation data uncertainty and uniform thresholds for change detection (TCDs) on the interpretation of volume change estimations. This application relies on products derived from unmanned aerial vehicle (UAV) surveys and on the evaluation of the uncertainty associated with volume change estimations to interpret the case study morphodynamics under non-extreme sea and wind conditions. The analysis was performed by comparing UAV-derived digital elevation models (DEMs)—root mean squared error (RMSE) vs. global navigation satellite system (GNSS) < 0.05 m—and orthophotos, considering the significance of the identified changes by applying a set of TCDs. In this case, a threshold of ~0.15 m was able to detect most of the morphological variations. The set of TCD ≤ 0.15 m was considered to discuss the significance of minor changes and the uncertainty of volume change calculations. During the analysed period (21 December 2016–20 January 2017), water levels and waves affected the front of the artificial dune by eroding the berm area; winds remodelled the entire dune, moving the loose sand around the dune and further inland; sediment volumes mobilised by sea and wind forcing were comparable. This work suggests that UAV-derived coastal morphological variations should be interpreted by integrating: (i) a set of uniform thresholds to detect significant changes; (ii) the uncertainty generated by the propagation of the original uncertainty of the elevation products; (iii) the characteristics of the morphodynamic drivers evaluated by adopting uncertainty-aware approaches. Thus, the contribution of subtle morphological changes—magnitudes comparable with the instrumental accuracy and/or the assessed propagated uncertainty—can be properly accounted for.

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Doré, Arnaud, Philippe Bonneton, Vincent Marieu e Thierry Garlan. "Numerical modeling of subaqueous sand dune morphodynamics". Journal of Geophysical Research: Earth Surface 121, n. 3 (marzo 2016): 565–87. http://dx.doi.org/10.1002/2015jf003689.

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Swanson, Travis, David Mohrig, Gary Kocurek, Benjamin T. Cardenas e Matthew A. Wolinsky. "Preservation of Autogenic Processes and Allogenic Forcings in Set-Scale Aeolian Architecture I: Numerical Experiments". Journal of Sedimentary Research 89, n. 8 (4 settembre 2019): 728–40. http://dx.doi.org/10.2110/jsr.2019.42.

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Abstract A reduced-complexity aeolian dune stratification model is developed and applied to explore the role of dune morphodynamics in the creation of synthetic sections of aeolian stratigraphy originating from three sets of environmental forcing: 1) steady wind transport capacity, 2) steady bed aggradation and variable wind transport capacity, and 3) steady wind transport capacity and bed aggradation. In each scenario, the forward motion of initial, highly disorganized dunes generates a significant record exclusively containing autogenic signals that arise from early dune growth, deformation, and merging. However, continued dune growth scours deeply, and shreds all records of early dunes. Afterward, dunes self-organize into quasi-stable groups. Forward motion of dune groups creates, truncates, and amalgamates sets and co-sets of cross-strata, quickly forming a second, significantly more robust stratigraphic record, which preserves a comingling of signals sourced from ongoing autogenic processes and each scenario's specific set of environmental forcings, the allogenic boundary conditions of the sand sea. Although the importance of self-organization on modeled aeolian stratification is clear in the few presented scenarios, self-organization may be throttled via variability in environmental forcings, as thoroughly documented in a companion paper (Cardenas et al., this issue). Therefore, additional work is warranted because this numerical experiment only begins to sample possible sets of environmental forcing, boundary conditions, and initial conditions, geomorphic responses, and consequential preservation possible in the presented surface-stratigraphic bedform modeling framework.

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Van Thiel de Vries, Jaap. "DUNE EROSION ABOVE REVETMENTS". Coastal Engineering Proceedings 1, n. 33 (14 dicembre 2012): 95. http://dx.doi.org/10.9753/icce.v33.sediment.95.

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In a situation with a narrow dune, the dune base can be protected with a revetment to reduce dune erosion during extreme events. To quantify the effects of a revetment on storm impact, the functionality of the numerical storm impact model XBeach (Roelvink et al., 2009) is extended to account for the complex morphodynamics around revetments. Here the focus is on dune erosion above revetments, which is simulated with a simple avalanching algorithm that is triggered by the combined runup of short waves and long waves. The simulated runup statistics depend on the incident wave groupiness and associated long wave variance.

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Gao, X., D. Zhang, O. Rozier e C. Narteau. "Transport capacity and saturation mechanism in a real-space cellular automaton dune model". Advances in Geosciences 37 (22 aprile 2014): 47–55. http://dx.doi.org/10.5194/adgeo-37-47-2014.

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Abstract. In a real-space cellular automaton dune model, individual physical processes such as erosion, deposition and transport are implemented by nearest neighbor interactions and a time-dependent stochastic process. Hence, the transport capacity, the saturation mechanism and the characteristic wavelength for the formation of dunes are emergent properties that can only be determined a posteriori from the output of the numerical simulations. Here we propose a simplified version of the model to establish asymptotic relations between the microscopic erosion-deposition-transport rate parameters and the characteristic length and time scales of the flux saturation mechanism. In particular, we show that, in the cellular automaton, the saturation length is a mean transport distance controlled by the deposition of mobile sedimentary cells. Then, we discuss how these results can be used to determine the sediment flux within dune fields and the rate parameters of a new class of discrete models that concentrate on the effect of heterogeneities in grain-size on dune morphodynamics.

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Kostaschuk, Ray A., e Jeremy G. Venditti. "Why do large, deep rivers have low-angle dune beds?" Geology 47, n. 10 (20 agosto 2019): 919–22. http://dx.doi.org/10.1130/g46460.1.

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Abstract Dunes are the most common bedform in sand-bedded rivers. Small, high-angle dunes (HADs) dominate in shallow (<2.5 m) flows and have lee sides with steep downstream-facing slipfaces (>24°) and reversed upslope-oriented flow in the separation vortex. In contrast, large, deep (>2.5 m) rivers have low-angle dunes (LADs) with gentle lee-side slipfaces (<24°; often <10°), little or no flow separation, and more-pronounced downslope currents. Avalanches driven primarily by particle interaction maintain slipfaces of HADs. On LADs, excess pore pressures that occur during the failure of thick, loosely packed deposits can produce liquefied avalanches that flow and stop on gentle gradients. As lee-side angles decrease over LADs, downslope currents increase in strength, accelerating avalanches, transporting bedload, and creating smaller, superimposed dunes and uniform concave slopes on the lee side. Nearly a century of research on dunes in shallow laboratory flows has assumed that dune morphodynamics are scale invariant, which is not true.

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Malvárez, Gonzalo, Derek Jackson, Fatima Navas, Ignacio Alonso e Luis Hernandez-Calvento. "A Conceptual Model for Dune Morphodynamics of the Corralejo Dune System, Fuerteventura, Spain." Journal of Coastal Research 165 (3 gennaio 2013): 1539–44. http://dx.doi.org/10.2112/si65-260.1.

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Shin, Sungwon, Jichang Kim, Jeseon Yoo, Kideok Do, Tae Soo Chang e Jinah Kim. "DUNE EROSION AND SAND BAR MIGRATION DURING A STORM EVENT: LARGE-SCALE WAVE FLUME TEST AND NUMERICAL SIMULATION". Coastal Engineering Proceedings, n. 36v (28 dicembre 2020): 34. http://dx.doi.org/10.9753/icce.v36v.sediment.34.

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The coastal sand dune is an important natural coastal protection system in the nearshore region from storm wave damage. USACE (2013) introduced coastal dune as Nature and Nature-Based Feature for coastal resilience. Therefore, accurately predicting the dune erosion and sediment transport is very important not only to protect the coastal community from the extreme wave but also to provide design guideline for restoration. However, the ability to accurately predict the coastal dune morphodynamics has not been enough improved. The main objective of this study is to investigate erosion and deposition mechanisms of dune and sand bar by obtaining the synoptic data set of movable bed experiment during the entire storm event. Using the experimental data, this study tried to verify the numerical model (XBeachX). Moreover, box cores were used to track the storm history in surf and swash zone.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/E-Itkn36rLQ

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Hugenholtz, Chris H., Stephen A. Wolfe e Brian J. Moorman. "Effects of sand supply on the morphodynamics and stratigraphy of active parabolic dunes, Bigstick Sand Hills, southwestern SaskatchewanGeological Survey of Canada Contribution 20060654." Canadian Journal of Earth Sciences 45, n. 3 (marzo 2008): 321–35. http://dx.doi.org/10.1139/e08-001.

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Sand supply is a major controlling factor on parabolic dune form and stratigraphy in inland settings. In this study, aerial photographs, ground-penetrating radar (GPR), and stratigraphic analysis document the morphodynamics of an individual and compound parabolic dune in the Bigstick Sand Hills, southwestern Saskatchewan. Migration rates for the last 60 years are comparable, although the profile morphologies differ, with the individual dune having a more aerodynamic form. Stratigraphic facies are also similar in both dune types, but the overall internal architecture imaged by GPR differs considerably. Configurations of cross-strata parallel to the downwind axis represent dominant foreset development and lee-slope slipface advance of the individual dune, and impeded slipface development of the compound dune. Stratigraphy transverse to the downwind axis represents radial deposition and foreset development at the individual dune, and vertical accumulation at the compound dune. The overall difference in parabolic dune form and stratigraphy is attributed to variations in sand supply, which determine vegetation development and sedimentation processes along the crest and lee slope. Sand supplied from active blowouts upwind of the individual dune inhibits vegetation colonization on the dune, whereas an absence of sand supply upwind of the compound dune leads to high levels of vegetation cover on the dune. Once supply drops below a threshold level, vegetation cover increases, causing sediment deposition and vertical accretion, and ultimately changing dune form. Overall, this study demonstrates that local sand supply and feedback processes are critical to understanding dune development in vegetated, inland settings.

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van der Vegt, M., e P. Hoekstra. "Morphodynamics of a storm-dominated, shallow tidal inlet: the Slufter, the Netherlands". Netherlands Journal of Geosciences - Geologie en Mijnbouw 91, n. 3 (novembre 2012): 325–39. http://dx.doi.org/10.1017/s0016774600000470.

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AbstractIn this article we study the morphodynamics of the Slufter on the short-term (months) and long-term (years to decades). The Slufter is a small, shallow tidal inlet located on the island of Texel, the Netherlands. A narrow (tens of meters) channel connects the North Sea with a dune valley of 400 ha. This narrow channel is located in between a 400-700 m wide opening in the dunes. Approximately 80% of the basin of the Slufter is located above mean high water level and is flooded only during storms, when a threshold water level is exceeded.Analysis of historical aerial photographs revealed that the inlet channel migrates about 100 m per year. In the 1970's it migrated to the south, while since 1980 it is migrating to the north. When the channel reached the dunes at the north side of the dune breach the channel was relocated to the south by man. The channel inside the backbarrier basin was less dynamic. It shows a gradual growth and southward migration of a meander on a decadal time scale.The short-term dynamics of the Slufter were studied during a field campaign in 2008. The campaign aimed at identifying the dominant hydrodynamic processes and morphological change during fair weather conditions and during storm events. During fair weather flow velocities in the main inlet channel were 0.5-0.8 m/s at water depths of 0-1.5 m, slightly ebb-dominant and associated morphological change was small. When water levels were above critical levels during a storm period the hydrodynamics in the main channel drastically changed. The flow in the main channel was highly ebb dominant. Long ebb periods with typical flow velocities of 2 m/s were alternated by much shorter flood periods with typical velocities of 0.5-1 m/s. This resulted in a net outflow of water via the main channel, while we measured a net inflow of water at the beach plain. During the storm period in 2008 we measured a 10 m migration of the channel to the north.We conclude that the Slufter is a storm-dominated tidal inlet system.

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Xu, Zhiwei, Joseph A. Mason e Huayu Lu. "Vegetated dune morphodynamics during recent stabilization of the Mu Us dune field, north-central China". Geomorphology 228 (gennaio 2015): 486–503. http://dx.doi.org/10.1016/j.geomorph.2014.10.001.

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Sabatier, François, Edward J. Anthony, Arnaud Héquette, Serge Suanez, Jonathan Musereau, Marie-Hélène Ruz e Hervé Regnauld. "Morphodynamics of beach/dune systems: examples from the coast of France". Géomorphologie : relief, processus, environnement 15, n. 1 (1 aprile 2009): 3–22. http://dx.doi.org/10.4000/geomorphologie.7461.

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Innocenti Degli, Emilia, Omar Defeo e Felicita Scapini. "Arthropodofauna richness and abundance across beach–dune systems with contrasting morphodynamics". Regional Studies in Marine Science 44 (maggio 2021): 101722. http://dx.doi.org/10.1016/j.rsma.2021.101722.

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Walker, Ian J., e Dan H. Shugar. "Secondary flow deflection in the lee of transverse dunes with implications for dune morphodynamics and migration". Earth Surface Processes and Landforms 38, n. 14 (18 aprile 2013): 1642–54. http://dx.doi.org/10.1002/esp.3398.

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Dissanayake, Pushpa, Jennifer Brown, Paul Wisse e Harshinie Karunarathna. "Comparison of storm cluster vs isolated event impacts on beach/dune morphodynamics". Estuarine, Coastal and Shelf Science 164 (ottobre 2015): 301–12. http://dx.doi.org/10.1016/j.ecss.2015.07.040.

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Elsayed, Saber M., e Nils Goseberg. "ROLE OF SPATIAL VARIABILITY OF SOIL RESISTANCE IN ALONGSHORE VARIABILITY OF COASTAL BARRIERS RESPONSE TO SUPERSTORM SURGES". Coastal Engineering Proceedings, n. 36v (31 dicembre 2020): 41. http://dx.doi.org/10.9753/icce.v36v.papers.41.

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Sand dunes and other natural coastal barriers (e.g. barrier islands) represent important components of the defense system against consequences of storm surges. However, in many coastal systems, major storm surges represent important drivers of coastal erosion. Increased extreme events potentially result in accelerated coastal erosion, coastal barrier breaching, and coastal flooding. The response of a barrier to a storm surge is often determined by mutual interaction among the driving hydrodynamics, the subsequent morphodynamics, and the local geology, including spatial variations of subaqueous bathymetry and subaerial topography. However, the effect of alongshore variability of soil properties on the alongshore varying response is not yet considered. Therefore, this study examines soil parameters that may affect coastal erosion during major storm surges. Moreover, it applies a novel extension of the numerical model XBeach that accounts for spatial variation of soil properties to an artificial dune system of spatially varying soil permeability. Results showed that variability of soil permeability alongshore the dune results in alongshore varying resistance to erosion so that breaches may occur at the locations of less resistance that are corresponding to locations of higher soil permeability. Outcomes of the numerical simulations proved also that reduced soil permeability represents a nature-based solution that increases the resilience of natural defense systems during major storm surges by mitigating rates of coastal erosion.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/1ERwbW5BmYA

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Passeri, Davina L., Matthew V. Bilskie, Scott C. Hagen, Rangley C. Mickey, P. Soupy Dalyander e Victor M. Gonzalez. "Assessing the Effectiveness of Nourishment in Decadal Barrier Island Morphological Resilience". Water 13, n. 7 (30 marzo 2021): 944. http://dx.doi.org/10.3390/w13070944.

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Nourishment has shown to be an effective method for short-term storm protection along barrier islands and sandy beaches by reducing flooding, wave attack and erosion. However, the ability of nourishment to mitigate the effects of storms and sea level rise (SLR) and improve coastal resilience over decadal time scales is not well understood. This study uses integrated models of storm-driven hydrodynamics, morphodynamics and post-storm dune recovery to assess the effectiveness of beach and dune nourishment on barrier island morphological resilience over a 30-year period, accounting for storms and a moderate amount of SLR. Results show that at the end of the 30 years, nourishment contributes to maintaining island volumes by increasing barrier height and width compared with a no-action scenario (i.e., no nourishment, only natural recovery). During storms where the collision regime was dominant, higher volumes of sand were lost from the wider beach in the nourishment scenario than in the no-action scenario. During stronger storms, nourishment reduced dune overtopping compared with the no-action scenario, allowing the island to maintain height and width. Additionally, nourishment was particularly effective in reducing breaching during back-to-back storms occurring in the same year.

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Ozkan, Cigdem, Talea Mayo e Davina L. Passeri. "The Potential of Wave Energy Conversion to Mitigate Coastal Erosion from Hurricanes". Journal of Marine Science and Engineering 10, n. 2 (21 gennaio 2022): 143. http://dx.doi.org/10.3390/jmse10020143.

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Wave energy conversion technologies have recently attracted more attention as part of global efforts to replace fossil fuels with renewable energy resources. While ocean waves can provide renewable energy, they can also be destructive to coastal areas that are often densely populated and vulnerable to coastal erosion. There have been a variety of efforts to mitigate the impacts of wave- and storm-induced erosion; however, they are either temporary solutions or approaches that are not able to adapt to a changing climate. This study explores a green and sustainable approach to mitigating coastal erosion from hurricanes through wave energy conversion. A barrier island, Dauphin Island, off the coast of Alabama, is used as a test case. The potential use of wave energy converter farms to mitigate erosion due to hurricane storm surges while simultaneously generating renewable energy is explored through simulations that are forced with storm data using the XBeach model. It is shown that wave farms can impact coastal morphodynamics and have the potential to reduce dune and beach erosion, predominantly in the western portion of the island. The capacity of wave farms to influence coastal morphodynamics varies with the storm intensity.

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Lashley, Christopher H., Xavier Bertin, Dano Roelvink e Gaël Arnaud. "Contribution of Infragravity Waves to Run-up and Overwash in the Pertuis Breton Embayment (France)". Journal of Marine Science and Engineering 7, n. 7 (2 luglio 2019): 205. http://dx.doi.org/10.3390/jmse7070205.

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Wave run-up and dune overwash are typically assessed using empirical models developed for a specific range of often-simplistic conditions. Field experiments are essential in extending these formulae; yet obtaining comprehensive field data under extreme conditions is often challenging. Here, we use XBeach Surfbeat (XB-SB)—a shortwave-averaged but wave-group resolving numerical model—to complement a field campaign, with two main objectives: i) to assess the contribution of infragravity (IG) waves to washover development in a partially-sheltered area, with a highly complex bathymetry; and ii) to evaluate the unconventional nested-modeling approach that was applied. The analysis shows that gravity waves rapidly decrease across the embayment while IG waves are enhanced. Despite its exclusion of gravity-band swash, XB-SB is able to accurately reproduce both the large-scale hydrodynamics—wave heights and mean water levels across the 30 × 10 km embayment; and the local morphodynamics—steep post-storm dune profile and washover deposit. These findings show that the contribution of IG waves to dune overwash along the bay is significant and highlight the need for any method or model to consider IG waves when applied to similar environments. As many phase-averaged numerical models that are typically used for large-scale coastal applications exclude IG waves, XB-SB may prove to be a suitable alternative.

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Zambrano-Cruzatty, Luis, Nina Stark e Alba Yerro. "THE EFFECT OF SHEAR STRENGTH AND MOISTURE CONTENT ON THE FLUID VELOCITY THRESHOLD OF WIND EROSION". Coastal Engineering Proceedings, n. 36 (30 dicembre 2018): 86. http://dx.doi.org/10.9753/icce.v36.sediment.86.

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Wind erosion is an important component of coastal dune morphodynamics, and has been subject to research since decades (e.g., Bagnold 1941; Han et al. 2009). However, many expressions to predict fluid threshold velocity for wind erosion are not generally valid. For instance, Han et al. (2009) showed that some expressions struggle to predict the threshold velocity for tropical and/or humid coastal areas. We hypothesize that a shear strength limit equilibrium approach can incorporate the effects of moisture content, particle sorting and shape, slope angle, and cohesion into a general equation that would be applicable to a range of environmental and soil conditions. The objective of this study is to test this hypothesis using data sets published by McKenna-Neuman and Nickling (1989).

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30

Andriolo, Umberto, Gil Gonçalves, Paula Sobral, Ángela Fontán-Bouzas e Filipa Bessa. "Beach-dune morphodynamics and marine macro-litter abundance: An integrated approach with Unmanned Aerial System". Science of The Total Environment 749 (dicembre 2020): 141474. http://dx.doi.org/10.1016/j.scitotenv.2020.141474.

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31

Villate, Diego A., Luana Portz, Rogério Portantiolo Manzolli e Javier Alcántara-Carrió. "Human Disturbances of Shoreline Morphodynamics and Dune Ecosystem at the Puerto Velero Spit (Colombian Caribbean)". Journal of Coastal Research 95, sp1 (26 maggio 2020): 711. http://dx.doi.org/10.2112/si95-138.1.

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32

Santos Silva, Antônio Emanuel dos', Matheus Silveira Pinheiro e Davis Pereira de Paula. "VARIAÇÃO MORFOSSEDIMENTAR DO SETOR EXTREMO OESTE DA PRAIA DO ICARAÍ, CAUCAIA-CE". Revista da Casa da Geografia de Sobral (RCGS) 21, n. 2 (30 settembre 2019): 364–80. http://dx.doi.org/10.35701/rcgs.v21n2.543.

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Ambientalmente as dunas frontais constituem estruturas verdes de proteção costeira contra o avanço do mar, em muitos casos, são responsáveis pela manutenção do equilíbrio sedimentar do sistema praia-duna, impedindo que processos como a erosão costeira e a inundação marinha se tornem danosos a sociedade civil e ao patrimônio construído. O objetivo deste estudo foi monitorar as variações morfológicas e sedimentares do sistema praia-duna entre os anos de 2016 e 2018, no trecho extremo oeste da Praia do Icaraí, através da determinação das taxas granulométricas, volumétricas e morfológicas do sistema praia-duna na Praia do Icaraí. Os procedimentos metodológicos foram divididos em três etapas principais: levantamento bibliográfico, geocartográfico e experimentos de campo. Considerou-se que as forçantes oceanográficas foram as principais responsáveis pela erosão e solapamento das dunas frontais presentes na área de estudo. Em linhas gerais, os resultados deste trabalho significam um importante instrumento de análise dos impactos das condicionantes oceanográficas e antrópicas sobre uma praia que sofre de erosão costeira acentuada. O estudo em um trecho mais preservado dessa praia indicou de forma direta os impactos sofridos em um litoral que vem passando por transformações contínuas em suas praias, como é o caso do litoral de Caucaia.Palavras-chave: Morfodinâmica; Sistema Praial; Dunas Frontais. ABSTRACTEnvironmentally the frontal dunes constitute green structures of coastal protection against the advance of the sea, in many cases, they are responsible for the maintenance of the sedimentary balance of the beach-dune system, preventing that processes such as coastal erosion and marine flooding become harmful to civil society and built heritage. The objective of this study was to monitor the morphological and sedimentary variations of the beach-dune system between the years 2016 and 2018, in the extreme west section of Icaraí Beach, by determining the granulometric, volumetric and morphological rates of the beach-dune system in Praia of Icaraí. The methodological procedures were divided into three main stages: bibliographic survey, geocartographic and field experiments. It was considered that the oceanographic forcings were the main responsible for the erosion and overlap of the frontal dunes present in the study area. In general terms, the results of this work represent an important instrument for analyzing the impacts of oceanographic and anthropogenic conditions on a beach that suffers from marked coastal erosion. The study in a more preserved stretch of this beach indicated in a direct way the impacts suffered on a coast that has undergone continuous transformations in its beaches, as is the case of the coast of Caucaia.Keywords: Morphodynamics; Praial System; Fore Dunes. RESUMENAmbientalmente, las dunas frontales son estructuras verdes de protección costera contra el avance del mar. En muchos casos, son responsables de mantener el equilibrio sedimentario del sistema de dunas de playa, evitando que procesos como la erosión costera y las inundaciones marinas dañen a la sociedad civil. y el patrimonio construido. El objetivo de este estudio fue monitorear las variaciones morfológicas y sedimentarias del sistema de dunas de playa entre 2016 y 2018, en el extremo occidental de Praia do Icaraí, determinando el tamaño de partícula, las tasas volumétricas y morfológicas del sistema de dunas de playa en Praia de Icaraí Los procedimientos metodológicos se dividieron en tres etapas principales: estudio bibliográfico, geocartográfico y experimentos de campo. El forzamiento oceanográfico se consideró el principal responsable de la erosión y el debilitamiento de las dunas frontales presentes en el área de estudio. En general, los resultados de este trabajo representan un instrumento importante para analizar los impactos de las condiciones oceanográficas y antropogénicas en una playa que sufre una severa erosión costera. El estudio en un tramo más preservado de esta playa indicó directamente los impactos sufridos en una costa que ha sufrido cambios continuos en sus playas, como es el caso de la costa de Caucaia.Palabras claves: Morfodinámica; Sistema de playa; Dunas frontales.

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33

Buynevich, I. V., M. Savarese, S. V. Kadurin, E. P. Larchenkov, L. E. Park Boush, H. A. Curran e I. A. Beal. "MORPHODYNAMICS AND GEOLOGICAL LEGACY OF BERM SCARPS ALONG NON-TIDAL (UKRAINE) AND MICROTIDAL (THE BAHAMAS) COASTS". Odesa National University Herald. Geography and Geology 19, n. 2(21) (16 aprile 2015): 177–87. http://dx.doi.org/10.18524/2303-9914.2014.2(21).41175.

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Berm scarps are erosional features characteristic of all coastal accumulation forms. Their profiles range from steep to overhanging (ψ>90) and evolve through slope adjustment and burial by swash and aeolian accretion. Examples from the mixed siliciclastic-bioclastic beaches of the non-tidal Black Sea coast of Ukraine and the microtidal oolitic-bioclastic carbonate islands of the Bahama Archipelago demonstrate a wide range of scarp morphologies. Truncations of berm strata and density lag at the scarp base accentuate their recognition in the field and in geophysical (georadar) records. Although ephemeral as surface features, berm scarps may act as nucleation sites for aeolian aggradation, thereby generating continuous coast-parallel dune ridges. Accumulation of organic debris promotes colonization of incipient foredunes by plants and provides chronological control of erosional events. Therefore, paleo-berm scarps serve as important geological indicators of past storm activity and aid in constraining sea-level position.

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IELPI, ALESSANDRO. "Lateral accretion of modern unvegetated rivers: remotely sensed fluvial–aeolian morphodynamics and perspectives on the Precambrian rock record". Geological Magazine 154, n. 3 (12 maggio 2016): 609–24. http://dx.doi.org/10.1017/s001675681600025x.

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AbstractModern unvegetated rivers flowing through aeolian-dune fields demonstrate potential as analogues for pre-vegetation fluvial landscapes. A prominent example is contained in the Lençóis Maranhenses of Brazil, a coastal aeolian system hosting the semi-perennial Rio Negro. Remotely sensed images covering c. 45 years display the rhythmic expansion and wind-driven shift of single-threaded and sinuous fluvial trunks alternating with wider braided plains. Sinuous tracts feature mid-channel and bank-attached bars, including expansional point bars with subdued relief. The morphology, accretion and sediment transport of unvegetated point bars in the Rio Negro are compared to the morphodynamics of vegetated meandering rivers. Unvegetated point bars are composed of large coalescent unit bars, lack apparent scroll topography and are preferentially attached to channel banks located on the windward side of the river course. Unvegetated meanders have expansional behaviour related to downwind channel trailing. Point bars maintain an expansional planform despite spatial confinement induced by aeolian dunes. Channel-flow impingement onto cohesion-less banks favours scouring of deep pools along the bar tails, which host bank-collapse deposits subsequently reworked into new bars. Analogies to Precambrian rivers suggest that ancient unvegetated fluvial landscapes were not unequivocally featured by low sinuosity, especially if characterized by a low gradient and stable discharge. This inference is supported by ongoing studies on Proterozoic fluvial–aeolian systems in the Canadian Shield. Lack of scroll topography introduces overlap with low-sinuosity fluvial facies models, underscoring the value of observing ancient fluvial deposits in planform, or along 3D sections where the palaeodrainage of channel bodies and attached bars can be compared.

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Milne, F. D., P. Dong e M. Davidson. "Natural Variability and Anthropogenic Effects on the Morphodynamics of a Beach–Dune System at Montrose Bay, Scotland". Journal of Coastal Research 280 (marzo 2012): 375–88. http://dx.doi.org/10.2112/jcoastres-d-10-00115.1.

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Oliveira, Filipa S. B. F., André B. Fortunato e Paula Freire. "Beach Nourishment Protection against Storms for Contrasting Backshore Typologies". Journal of Marine Science and Engineering 12, n. 9 (23 agosto 2024): 1465. http://dx.doi.org/10.3390/jmse12091465.

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The protection against a storm event provided by nourishment to Costa da Caparica beaches near Lisbon, Portugal, is investigated numerically with a two-dimensional-horizontal morphodynamic model able to generate and propagate the longer infragravity waves. The beach has a groyne field and a multi-typology backshore. The nourishment of 106 m3 of sand was placed at the beach face and backshore. Pre- and post-nourishment topo-bathymetric surveys of the beach, which suffers from chronic erosion, were performed under a monitoring program. The morphodynamics of the pre- and post-nourished beach when exposed to a simulated historically damaging storm event and the post-storm morphologies were compared to evaluate the efficacy of the nourishment. Results indicate that the lower surface level of the beach face and backshore of the pre-nourished beach induces a larger erosion volume. The nourishment prevented the extreme retreat of the shoreline that occurred during the storm in the pre-nourished beach and reduced the storm-induced erosion volume by 20%, thus protecting the beach effectively against the storm. The beach backshore typology (seawall vs. dune) exerts differential influences on the sandy bottom. As a result, multi-typology backshores induce alongshore variability in cross-shore dynamics. The backshore seawalls exposed to direct wave action cause higher erosion volumes and a larger cross-shore extension of the active zone. The most vulnerable alongshore sectors of the beach were identified and related to the mechanisms responsible for the erosion phenomenon. These findings strengthen the importance of sand nourishment for the protection and sustainability of beaches, particularly those with a seawall at the backshore, where storm events cause higher erosion.

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Anthony, Edward J. "Storms, shoreface morphodynamics, sand supply, and the accretion and erosion of coastal dune barriers in the southern North Sea". Geomorphology 199 (ottobre 2013): 8–21. http://dx.doi.org/10.1016/j.geomorph.2012.06.007.

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Hilgendorf, Zach, M. Colin Marvin, Craig M. Turner e Ian J. Walker. "Assessing Geomorphic Change in Restored Coastal Dune Ecosystems Using a Multi-Platform Aerial Approach". Remote Sensing 13, n. 3 (20 gennaio 2021): 354. http://dx.doi.org/10.3390/rs13030354.

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Uncrewed aerial systems (UAS) provide an effective method to examine geomorphic and vegetation change in restored coastal dune ecosystems. Coupling structure-from-motion (SfM) photogrammetry with RGB orthomosaic imagery allows researchers to characterize spatial-temporal geomorphic responses associated with differences in vegetation cover. Such approaches provide quantitative data on landscape morphodynamics and sediment erosion and deposition responses that allow scientists and land managers to assess the efficacy of dynamic restoration efforts and, in turn, make informed decisions for future restoration projects. Two different restored coastal foredune sites in Humboldt County, California were monitored between 2016–20 with UAS (quadcopter and fixed-wing), kite aerial photogrammetry (KAP), and terrestrial laser scanning (TLS) platforms. We compared our KAP- and UAS-SfM elevation models to concurrently collected TLS bare earth models for five of our fifteen collections. The goal of this study was to inform on the potential of a multi-platform aerial approach for calculating geomorphic differences (i.e., topographic differencing), in order to quantify sediment erosion and deposition, and vegetation change over a coastal dune ecosystem. While UAS-SfM datasets were relatively well fit to their TLS counterparts (2.1–12.2% area of difference), the KAP-SfM surfaces exhibited higher deviations (23.6–27.6%) and suffered from systematic collection inconsistencies related to methods and susceptibility to external factors (e.g., the influence of wind speed and direction on variable altitude, image overlap, and coverage extent). Finally, we provide commentary on the logistical considerations regarding KAP and UAS data collection and the construction of uncertainty budgets for geomorphic change detection (GCD), while providing suggestions for standardizing methods for uncertainty budgeting. While we propose an approach that incorporates multiple levels of collection- and processing-based uncertainty, we also recognize that uncertainty is often project-specific and outline the development of potential standards for incorporating uncertainty budgets in SfM projects.

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Camacho-Valdéz, Vera, Janette M. Murillo-Jiménez, Enrique H. Nava-Sánchez e Cuauhtémoc Turrent-Thompson. "Dune and Beach Morphodynamics at Cabo Falso, Baja California Sur, Mexico: Response to Natural, Hurricane Juliette (2001) and Anthropogenic Influence". Journal of Coastal Research 243 (maggio 2008): 553–60. http://dx.doi.org/10.2112/05-0575.1.

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Turki, Imen, Sophie Le Bot, Nicolas Lecoq, Hassan Shafiei, Charlotte Michel, Julien Deloffre, Arnaud Héquette, Vincent Sipka e Robert Lafite. "Morphodynamics of intertidal dune field in a mixed wave-tide environment: Case of Baie de Somme in Eastern English Channel". Marine Geology 431 (gennaio 2021): 106381. http://dx.doi.org/10.1016/j.margeo.2020.106381.

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Lucas, A., S. Rodriguez, F. Lemonnier, A. Le Gall, S. MacKenzie, C. Ferrari, P. Paillou e C. Narteau. "Texture and Composition of Titan's Equatorial Sand Seas Inferred From Cassini SAR Data: Implications for Aeolian Transport and Dune Morphodynamics". Journal of Geophysical Research: Planets 124, n. 11 (novembre 2019): 3140–63. http://dx.doi.org/10.1029/2019je005965.

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Tsoar, H. "Linear dunes - forms and formation". Progress in Physical Geography: Earth and Environment 13, n. 4 (dicembre 1989): 507–28. http://dx.doi.org/10.1177/030913338901300402.

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Most geomorphologists and geologists do not differentiate the various types of linear dune and refer to them as one dune type mainly in the terms of linear, longitudinal or seif dunes. In recent morphodynamic and genetic classifications of dunes, all types of linear dunes are lumped under the heading of longitudinal dunes (Wasson and Hyde, 1983; Hunter et al., 1983). This review, however, substantiates three different simple linear dunes - lee dunes, seifs and vegetated- linear - each of which has a different shape and mechanism of formation and elongation.

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Kilibarda, Zoran, e Vesna Kilibarda. "Foredune and Beach Dynamics on the Southern Shores of Lake Michigan during Recent High Water Levels". Geosciences 12, n. 4 (28 marzo 2022): 151. http://dx.doi.org/10.3390/geosciences12040151.

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From 18 January 2013 (175.16 m a.s.l.) to 8 September 2020 (177.82 m a.s.l.), Lake Michigan experienced its fastest and highest rise (2.67 m) since 1860, when instrumental measurements began. Extensive foredunes developed since the last high lake levels began eroding in 1997 at fast rates. This study focuses on coastal morphodynamics along the 800 m coast within the central Indiana Dunes State Park on Lake Michigan’s southern shores during this time. Severe foredune erosion, in terms of total horizontal dune loss and total volume of eroded sand, occurred unevenly over the three-year period, both temporally, during a single storm, a season, a year, or three years, and spatially, in the eastern, central, and western study areas. Late autumn storms accounted for most foredune erosion in 2018 and 2019, when foredune scarps retreated up to 4 and 9 m, respectively. Erosion was highest in the updrift eastern study area, where about 8 m3/m of sand was removed in 2018 and about 19 m3/m of sand was removed in 2019. The lack of shelf ice along the shore, rising lake levels, and convective storms that triggered meteotsunamis changed the foredune erosion pattern in 2020. Erosion became most vigorous in the downdrift central (13 m scarp retreat) and western (11 m scarp retreat) study areas. The average volume of eroded sand (21.5 m3/m) was more than double that of 2019 (8 m3/m), and almost quadruple the 2018 volume (5.5 m3/m). After foredune erosion events, the beach rapidly recovered and maintained its width as the shoreline migrated landward. On many occasions following these severe erosion events the dry portion of the beach aggraded and absorbed significant sand amounts removed from the foredunes. The remaining sand was transferred to the surf zone, where it changed the sand bar morphology and led to their coalescence and flattening.

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Wolfert, H. P., e G. J. Maas. "Downstream changes of meandering styles in the lower reaches of the River Vecht, the Netherlands". Netherlands Journal of Geosciences 86, n. 3 (settembre 2007): 257–71. http://dx.doi.org/10.1017/s0016774600077842.

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AbstractThe morphodynamics of the lower River Vecht, the Netherlands, and the influence of geomorphological setting and bank composition on meander migration were studied by means of reconstructing the pre-channelization landform configuration on a scale of 1 : 25,000, using historical maps from 1720, 1850 and 1890 A.D. and other data.A downstream sequence of reaches was observed, each with a typical fluvial style and channel migration rate: (a) a narrow meander belt and a highly sinuous channel with intermediate migration rate, in the middle of an extensive floodbasin; (b) a wide meander belt and high rates of lateral channel migration, especially where large meanders impinged upon valley bluffs, as part of an incised setting; (c) a low sinuosity, embanked channel with low rates of downstream migration because of confinement by dikes, occurring in an inland delta with sandy sediments.Local variation in meander migration rates was observed within reach B. This was caused by the spatial variability of bank resistance as reflected by the width-depth ratio of the channel and the silt-clay ratios of deposits. River banks are: 1) very erodible when consisting of channel deposits, aeolian dune deposits or when coarse fluvio-periglacial deposits occur at their base; 2) erodible when dominated by overbank deposits or aeolian sand sheet deposits; 3) resistant when a plaggen-layer is exposed; and 4) very resistant when dominated by floodbasin deposits.These implications of meander variability enable to assess the effects of the rehabilitation of the meandering process.

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Moura, Marisa Ribeiro, e João Capistrano de Abreu Neto. "Evolução da Linha de Costa da Praia do Iguape, Aquiraz, Ceará, Brasil (Evolution of the Shoreline of the Iguape Beach, Aquiraz, Ceará, Brazil)". Revista Brasileira de Geografia Física 7, n. 1 (1 aprile 2014): 044–53. http://dx.doi.org/10.26848/rbgf.v7.1.p044-053.

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Esta pesquisa buscou por meio de métodos diretos e indiretos analisar a evolução da linha de costa da praia do Iguape, no litoral do município de Aquiraz, identificando os processos erosivos atuantes na área no período de 2004 a 2012. Localizada a aproximadamente 28 km de Fortaleza, a praia do Iguape possui diversos usos, seja para atividades turísticas, seja para atividades tradicionais como a pesca por jangadas. Contudo, devido o aceleramento da urbanização e de áreas de lazer, iniciadas na década de 1970 em ambientes de faixa praial e campo de dunas, a paisagem local passou a mudar tornando este espaço geográfico um ambiente de tensão ambiental. Estas mudanças provocaram alteracões na morfodinâmica e hidrodinâmica da área, que passou a experimentar processos erosivos, atribuído ao recuo da linha de costa e a diminuição do suporte sedimentar com a ocupação de dunas. Por conseguinte, muros residenciais, barracas, restaurantes e estruturas de proteção foram destruídos pela ação das ondas na área. Diante disso, através de monitoramento da morfodinâmica e da hidrodinâmica e de estudos de geoprocessamento na análise de (re)ordenamento, caracterização física e processos de uso e ocupação do espaço, a presente pesquisa teve como objetivo caracterizar a evolução dos processos erosivos na praia do Iguape. A metodologia contemplou pesquisa bibliográfica, trabalhos de campo e laboratório utilizando materiais específicos e imagens aéreas dos anos de 2004, 2009 e 2011. Verificou-se que os problemas costeiros como o avanço do mar, fortes ondas, destruição de dunas móveis e a diminuição da faixa praial provocaram a erosão pontual que ocasionou na destruição dos estabelecimentos localizados na faixa praial e pós-praia, atingindo um recuo de média de -0,76 m/ano, acarretando no recuo de 6,08 m nos últimos oito anos. A B S T R A C T This research sought through direct and indirect methods to analyze the evolution of the shoreline Iguape Beach, on the coast of the municipality of Aquiraz, identifying erosion processes active in the area in the period of 2004 to 2012. Located approximately 28 km from Fortaleza, the Iguape beach has many uses, whether for tourism activities, whether for traditional activities such as fishing by jangadas. However, due to the acceleration of urbanization and recreation areas, initiated in the 1970s in environments praial track and dune field, the local landscape began to change making this geographical space an environment of environmental stress. These changes led to changes in hydrodynamics and morphodynamics of the area, which is now experiencing erosion, attributed to the retreat of the shoreline and reduced sediment support because of the occupation of dunes. Therefore, residential walls, stalls, restaurants and protective structures were destroyed by wave action in the area. In front of this, monitoring the morphodynamic and hydrodynamic studies and GIS in the analysis of (re)planning, physical characterization and processes for use and occupation of space, the present study aimed to characterize the evolution of erosion on the Iguape beach. The methodology included literature research, field work and laboratory using specific materials and aerial imagery of the years 2004, 2009 and 2011. It has been found that problems such as the advancement of sea, strong waves, mobile dunes destruction and reduction the strip of beach caused the localized erosion which caused the destruction of outlets located in beach zone and post shore, reaching a mean decrease of -0.76 m/year, resulting in a decrease of 6.08 m in the last eight years. Keywords: shoreline, geoprocessing, Iguape beach, use and occupation, erosion processes.

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El Mrini, Abdelmounim, Edward J. Anthony, Mohammed Taaouati, Driss Nachite e Mohamed Maanan. "A note on contrasting morphodynamics of two beach systems with different backshores, Tetouan coast, northwest Morocco: the role of grain size and human-altered dune morphology". Journal of Coastal Research 165 (3 gennaio 2013): 1283–88. http://dx.doi.org/10.2112/si65-217.1.

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47

Lyons, Mitchell B., Charlotte H. Mills, Christopher E. Gordon e Mike Letnic. "Linking trophic cascades to changes in desert dune geomorphology using high-resolution drone data". Journal of The Royal Society Interface 15, n. 144 (luglio 2018): 20180327. http://dx.doi.org/10.1098/rsif.2018.0327.

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Vegetation cover is fundamental in the formation and maintenance of geomorphological features in dune systems. In arid Australia, increased woody shrub cover has been linked to removal of the apex predator (Dingoes, Canis dingo ) via subsequent trophic cascades. We ask whether this increase in shrubs can be linked to altered physical characteristics of the dunes. We used drone-based remote sensing to measure shrub density and construct three-dimensional models of dune morphology. Dunes had significantly different physical characteristics either side of the ‘dingo-proof fence’, inside which dingoes are systematically eradicated and shrub density is higher over vast spatial extents. Generalized additive models revealed that dunes with increased shrub density were higher, differently shaped and more variable in height profile. We propose that low shrub density induces aeolian and sedimentary processes that result in greater surface erosion and sediment transport, whereas high shrub density promotes dune stability. We speculate that increased vegetation cover acts to push dunes towards an alternate stable state, where climatic variation no longer has a significant effect on their morphodynamic state within the bi-stable state model. Our study provides evidence that anthropogenically induced trophic cascades can indirectly lead to large-scale changes in landscape geomorphology.

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Prodanov, Bogdan, Lyubomir Dimitrov, Iliyan Kotsev, Radoslava Bekova e Todor Lambev. "Spatial distribution of sand dunes along the Bulgarian Black Sea Coast: inventory, UAS mapping and new discoveries". Nature Conservation 54 (5 dicembre 2023): 81–120. http://dx.doi.org/10.3897/natureconservation.54.105507.

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Coastal sand dunes are amongst the world’s most sensitive and dynamic landforms. Unfortunately, during the last thirty years, heavy anthropogenic alterations have been observed, encompassing the greater part of the Bulgarian Black Sea coast (BBSC), which has changed the land-sea interactions significantly. As a consequence, the depositional coast has shrunk to 131 km or 25% of the aggregate Bulgarian Black Sea shoreline length. Although our research reveals that 86% of BBSC dunes are included in the Natura 2000 network of protected sites established under the Habitats Directive (Council Directive 92/43/EEC 1992), they are often heavily modified, subjected to environmental vandalism and destroyed due to mismanagement or lack of accurate information and prevention. These facts were the main reason for carrying out an inventory of the Bulgarian Black Sea coastal dune systems in 2021-2022. Our research aimed to identify all dune systems/sand dunes, update their spatial distribution and classify the observed coastal sand dunes landforms along the BBSC. The article demonstrates a successful methodology for combining unmanned aerial systems (UAS), Structure-from-Motion (SfM) photogrammetry, in situ sediment sampling, video imaging and verification and GNSS-RTK ground control points for coastal mapping. As of June 2022, over 97% of the Bulgarian shoreline has been surveyed with this technique, excluding military areas and national security sites. Based on the acquired data, as of 2021, the shoreline length was estimated to be 518.7 km at a scale 1:5000. The integrated UAS approach includes using Digital surface models (DSM), raster orthophotomosaics (OM) and 3D models, based on SfM photogrammetry to analyse the coastal topography, detect dune forms and update their spatial distribution. Throughout the inventory, 46 beach-dune systems were identified along the BBSC, which were divided into 62 dune sectors. The area of coastal dune systems was estimated at 988.21 ha (0.0089% of Bulgaria) and a total length of 73 km (14% of the shoreline). A comprehensive geomorphological analysis of the relationships between landforms morphology, aeolian and morphodynamic processes, vegetation density and type was the basis for the coastal dune landforms (CDLs) or dune systems to be classified into primary (312 ha; 32%) and secondary (676 ha; 68%). Additionally, the CDLs were classified according to Natura 2000 habitats: fixed (grey) dunes (546.27 ha; 55.28%), wooded dunes (222.61 ha; 22.53%), shifting (white) dunes (150.30 ha; 15.21%), embryonic dunes (68.3 ha; 6.91%) and humid dune slacks (0.94 ha; 0.09%). The highest positioned CDLs on the Balkan Peninsula were registered at perched Sozopol Sand Dunes (61 m a.s.l.) and cliff-top dunes at Arkutino (50.2 m a.s.l.). The multi-temporal analysis of photogrammetric DSMs and raster OMs showed the permanent loss of five dune systems in the Pomorie-Burgas-Rosenets coastal sector. The accrued UAS data approach allowed us to identify and map eight dune systems for the first time: Zlatni Pyasatsi (Panorama), Asparuhovo (Varna), Byala, Atanasovska Kosa, Central Beach (Burgas), Chernomorets, Kavatsite (partly) and Rezovo-Kastrich. A high anthropogenic footprint was registered on 50.7 ha (5.1%) of the entire dune surface. In the final stage of the study, human interventions that caused degradation and permanent loss of dunes (12 ha) over the last 15 years along the BBSC were shown. The main causes for dune degradation along BBSC have been documented, such as massive tourism development after the socialist period, road construction, recreational pressure exerted on the dunes, human trampling, lack of designated footpaths in areas with fixed and mobile dunes, off-road vehicles and parking lots (especially at camping sites), dumping of garbage and anthropogenic marine litter on the sand dunes etc.

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Chang, Tae Soo, Seok Hwi Hong, Seung Soo Chun e Jeong-Heon Choi. "Age and morphodynamics of a sandy beach fronted by a macrotidal mud flat along the west coast of Korea: a lateral headland bypass model for beach-dune formation". Geo-Marine Letters 37, n. 4 (17 novembre 2016): 361–71. http://dx.doi.org/10.1007/s00367-016-0486-y.

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50

Fairley, Iain, Jose Horrillo-Caraballo, Ian Masters, Harshinie Karunarathna e Dominic E. Reeve. "Spatial Variation in Coastal Dune Evolution in a High Tidal Range Environment". Remote Sensing 12, n. 22 (10 novembre 2020): 3689. http://dx.doi.org/10.3390/rs12223689.

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Coastal dunes have global importance as ecological habitats, recreational areas, and vital natural coastal protection. Dunes evolve due to variations in the supply and removal of sediment via both wind and waves, and on stabilization through vegetation colonization and growth. One aspect of dune evolution that is poorly understood is the longshore variation in dune response to morphodynamic forcing, which can occur over small spatial scales. In this paper, a fixed wing unmanned aerial vehicle (UAV), is used to measure the longshore variation in evolution of a dune system in a megatidal environment. Dune sections to the east and west of the study site are prograding whereas the central portion is static or eroding. The measured variation in dune response is compared to mesoscale intertidal bar migration and short-term measurements of longshore variation in wave characteristics during two storms. Intertidal sand bar migration is measured using satellite imagery: crescentic intertidal bars are present in front of the accreting portion of the beach to the west and migrate onshore at a rate of 0.1–0.2 m/day; episodically the eastern end of the bar detaches from the main bar and migrates eastward to attach near the eastern end of the study area; bypassing the central eroding section. Statistically significant longshore variation in intertidal wave heights were measured using beachface mounted pressure transducers: the largest significant wave heights are found in front of the dune section suffering erosion. Spectral differences were noted with more narrow-banded spectra in this area but differences are not statistically significant. These observations demonstrate the importance of three-dimensionality in intertidal beach morphology on longshore variation in dune evolution; both through longshore variation in onshore sediment supply and through causing longshore variation in near-dune significant wave heights.

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