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Nearshore incised valleys are important conduits for the transport of sediment, nutrients, pollutants and organic carbon from the continents to the sea. Therefore, it is essential to understand the autogenic evolution of deltas confined within incised valleys and how such evolution is affected by relative sea‐level rise. To date, limited research has focused on how deltas constrained by incised valleys or other forms of antecedent topography respond to rising sea level. An existing theory of autostratigraphy envisages scenarios in which two‐dimensional or unconfined three‐dimensional fan deltas can experience three evolutionary stages under constant rates of relative sea‐level rise and sediment supply: progradation, autoretreat and post‐autobreak transgression. In this work, an integrated study of geometric numerical models and physical experiments is undertaken to investigate autostratigraphic delta evolution for a variety of incised‐valley geometries, under conditions of constant rates of relative sea‐level rise and sediment supply. Results indicate that interplays of antecedent topography (valley geometries) and sediment mass balance expressed in resultant deltaic geometries can result in autogenic changes in shoreline dynamics and river avulsion frequency on deltas. The following primary findings arise. (i) Compared to valleys with rectangular and trapezoidal cross‐sectional profiles, valleys with triangular cross‐sections tend to contain deltas that experience faster rates of progradation, autoretreat and post‐autobreak transgression under rising sea level, and exhibit a more prominent convex‐seaward shoreline trajectory. (ii) The shoreline trajectory is also related to delta topset geometry, becoming more convex‐seaward under decreasing topset slopes. (iii) River avulsion frequency on deltas with rising sea level varies markedly across valleys with different geometries, even under the same rate of relative sea‐level rise; this is attributed to the difference in temporal evolution of shoreline migration for different valley geometries and the resultant difference in the delta topset aggradation. This study highlights complexities in responses of sedimentary systems under the confinement of different topographic configurations that have hitherto largely been overlooked in sequence‐stratigraphic models. The findings provide insight into future shoreline behaviour and river avulsion hazard on confined deltas, and for decoding the stratigraphic record. [ABSTRACT FROM AUTHOR]

Developed barrier systems (barrier islands and spits) are lowering and narrowing with sea‐level rise (SLR) such that habitation will eventually become infeasible or prohibitively expensive for most communities in its current form. Before reaching this state, choices will be made to modify the natural and built environment to reduce relatively short‐term risk. These choices will likely vary substantially even along the same developed barrier system as these landscapes are rarely uniformly managed alongshore. Building on the results from a companion paper, here we use a new modeling framework to investigate the complexities in barrier system dynamics that emerge as a function of alongshore variability in management strategies, accelerations in SLR, and changes in storm intensity and frequency. Model results suggest that when connected through alongshore sediment transport, barriers with alongshore variable management strategies—here, the construction of dunes and wide beaches to protect either roadways or communities—evolve differently than they would in the absence of alongshore connections. Shoreline stabilization by communities in one location influences neighboring areas managed solely for roadways, inducing long‐term system‐wide lags in shoreline retreat. Conversely, when barrier segments managed for roadways are allowed to overwash, this induces shoreline curvature system‐wide, thus enhancing erosion on nearby stabilized segments. Feedbacks between dunes, storms, overwash flux, and alongshore sediment transport also affect outcomes of climate adaptation measures. In the case of partial, early abandonment of roadway management, we find that system‐wide transitions to less vulnerable landscape states are possible, even under accelerated SLR and increased storminess. Plain Language Summary: Because humans inhabit barrier islands and spits (collectively referred to as "barriers") these landscapes, that would otherwise naturally change shape in response to storms and sea‐level rise (SLR), are influenced by efforts to protect development with wide beaches and tall dunes. These features interfere with a process called overwash, which transports sand landward during storms, building barrier elevation relative to sea level. Here, we use a new model to better understand how these interactions influence the habitability of barriers over time. Our simulations show that different management decisions made for adjacent coastal segments affect each other in positive and negative ways. When communities nourish beaches, adjacent to segments managed for roadways, some nourished sand reaches the adjacent segments, reducing shoreline erosion there. Conversely, portions of barriers that are managed only for roadways allow some overwash to reach the barrier interior; this negatively affects neighboring communities by enhancing their shoreline erosion rates. We find that early abandonment of dune management along portions of barriers may prevent highly vulnerable future states, such as barrier drowning. As communities explore choices for climate adaptation, our findings reveal the importance of coordination among decision makers in adjacent communities to avoid undesirable outcomes. Key Points: When management strategies vary alongshore, their effects are coupled via alongshore sediment redistribution, influencing barrier evolutionBeach nourishment (along portions of barriers) induces system‐wide lags in shoreline retreat, even decades after nourishment practices ceaseMore overwash (due to lower dunes or increased storminess) can prolong habitability, but drives increased nourishment frequency elsewhere [ABSTRACT FROM AUTHOR]

During a storm, as the beach profile is impacted by increased wave forcing and rapidly changing water levels, sand berms may help mitigate erosion of the backshore. However, the mechanics of berm morphodynamics have not been fully described. In this study, 26 trials were conducted in a large wave flume to explore the response of a near‐prototype berm to scaled storm conditions. Sensors were used to quantify hydrodynamics, sheet flow dynamics, and berm evolution. Results indicate that berm overtopping and offshore sediment transport were key processes causing berm erosion. During the morphological evolution of the beach profile, two sand bars were formed offshore that attenuated subsequent wave energy. The landward extent of that energy was confined to the seaward foreshore, inhibiting inundation of the backshore. Net offshore‐directed transport was dominant when infragravity motions increased in the swash zone. Conversely, the influence of incident‐band motions on sediment transport was relatively greater in the inner‐surf zone. Near‐bed flow velocities and sheet flow layer thicknesses were larger in the swash zone than in the inner‐surf zone. This paper also provides a valuable analysis between morphology‐estimated total sediment transport rates and rates derived from in situ measurements. Sheet flow dynamics dominated foreshore cross‐shore sediment processes, constituting the largest portion of the total sediment transport load throughout the berm erosion. Plain Language Summary: Coastal berms are natural sand barriers between the ocean and the back beach. During storms, berms may help prevent or slow down the erosion of the beach. A large‐scale laboratory experiment was conducted to study sediment transport and how berms erode. Sensors were used to measure water levels, flow velocities, sediment concentrations, and beach profile changes. The findings indicate that berm erosion was primarily caused by swash processes occurring as waves overtopped the berm. Offshore sediment transport resulted in the formation of two sand bars that helped dissipate subsequent wave energy. Overall, by quantifying processes leading to berm erosion, we can enhance our understanding of coastal dynamics, implement effective measures to protect beaches during storms, and safeguard against flooding. Key Points: Wave overtopping, runup, and low‐frequency motions are the main processes of berm erosionDuring early storm stages, near‐bed flow velocities and sheet layer thicknesses are larger in the swash zone than in the inner‐surf zoneQuantification of sediment transport rates indicates the dominance of sheet flow layer load at the foreshore, throughout the berm erosion [ABSTRACT FROM AUTHOR]

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. Plain Language Summary: Beach erosion and land inundation occur when wave runup exceeds the crest of dunes during extreme natural hazards. Dunes play a crucial role in coastal defense by reducing sediment loss and maintaining beach stability. To understand the hydrodynamic conditions and morphology change during the overwash process, we set up a dune‐beach experiment in a laboratory flume. With the support of high‐speed camera technology, this study examines the response of dunes during the overwash process and the changes in dune feature points. It is pointed out that dune erosion shows a relationship with wave energy flux and is consistent with shoreline recession. Moreover, secondary dunes can effectively reduce coastal erosion during overwash. Key Points: The experiment reveals that the inflection point in dune crest movement during overwash corresponds to the maximum overwash water rateOverwash water volume is linearly related to deposited sediment volume, while dune erosion volume is proportional to wave energy fluxThe presence of secondary dunes significantly reduced coast erosion during overwash, reducing shoreline retreat by over 40% [ABSTRACT FROM AUTHOR]

Coastal barrier systems are low‐lying environments that bear the brunt of storm impacts, with cumulative and complex consequences for barrier evolution. Most studies of barrier responses to storms examine what happens when water and sediment get driven landward across a barrier from its ocean side. Sherwood et al. (2023, https://doi.org/10.1029/2022jf006934) investigate the effects of overland flow and sediment transport forced across a barrier in the opposite direction—from its sheltered side, seaward. Using high‐resolution imagery of a barrier island observed before and after a hurricane, Sherwood et al. (2023, https://doi.org/10.1029/2022jf006934) show that "outwash" flow across the barrier shifted several times more sediment by volume than is typically reported for beach and dune erosion from onshore forcing. Their findings are remarkable because they are not exceptional: a related survey of barriers along the Atlantic and Gulf Coasts of the USA observed patterns of outwash morphology essentially everywhere. Insights into outwash morphology open exciting questions regarding the overlooked role of storm‐driven seaward sediment transport in barrier dynamics, with important implications for post‐storm barrier recovery and barrier evolution over decades to centuries. Plain Language Summary: Coastal barrier systems—beaches backed by dunes, marshes, and often a lagoon or sound—offer natural protection to coastal floodplains by absorbing some of the physical impacts of storms, including hurricanes. Most studies of storm impacts on coastal barriers investigate changes that occur when a storm drives water and sediment landward, over a barrier from its ocean‐facing side. But storms also drive sediment‐laden flows in the opposite direction: over the back of a barrier from its more sheltered side, toward the ocean. Here, I highlight work by Sherwood et al. (2023, https://doi.org/10.1029/2022jf006934) that details extensive patterns of erosion and accretion from "outwash" flow seaward over a barrier during a hurricane. Added up over time, sediment shifting landward and seaward across a barrier shapes the barrier landscape and affects how the barrier may respond to future storm impacts. Sherwood et al. (2023, https://doi.org/10.1029/2022jf006934) offer findings with important implications for understanding how coastal barriers evolve in space and time, and address a question that is fundamental to many geomorphic systems: when a large volume of sediment moves during an extreme weather event, where does it all go? Key Points: Sediment transport seaward during storms remains largely overlooked in coastal researchSeaward outwash may shift more sediment by volume than onshore‐forcing processes of beach and dune erosionThe complex relationship between storm‐driven seaward transport and barrier recovery opens exciting questions regarding barrier evolution [ABSTRACT FROM AUTHOR]

The northern California littoral cell of the Klamath River, which is a mixed rocky and sandy system with significant shoreline curvature, was investigated by examining ∼40 yr of satellite‐derived shoreline positions and historical records. We find that an accretion wave of sediment was initiated near the Klamath River mouth in the late 1980s and translated downcoast over the subsequent decades. The wave passed rapidly (∼2,500 m/yr) through a rocky coastal reach with more oblique wave directions and slowly through a sandy reach (∼200 m/yr) where wave crests approach at more normal angles. Within the sandy reach, the accretion wave extended over 200 m offshore, was ∼10 km long, incorporated 20 ± 6 million m3 of sediment, and averaged 1.3 ± 0.4 million m3/yr of longshore sediment transport over a 20‐yr interval. Diffusion of the accretion wave was observed, but the diffusivity coefficient (εobs ∼0.01 m2/s) was lower than values predicted by theory, which we attribute to net sediment transport convergence in the study area caused by the curvature of the shoreline. Examining historical records, we find that increased sediment discharge in the Klamath River occurred during the 20th century from industrial‐scale logging and climatic extremes. Thus, we hypothesize that increased river sediment discharge introduced new sediment to the littoral cell that initiated the observed accretion wave. These hypotheses can be tested with stratigraphic and mineralogic investigations of the broad study area beach that has formed during the past 150 years. Plain Language Summary: The existence of beaches along the world's coasts is dependent on the availability of sand or other sediment sources that build up these landforms. As sediment sources come and go over time, beaches may accrete or erode in response to these changes. These kinds of shoreline change patterns can be measured using new satellite‐based techniques that are especially valuable for coasts with limited ground‐based surveys. We applied these satellite‐based shoreline techniques to a portion of the northern California coast, which revealed that a massive body of sediment appeared on this coast in the 1980s, and that this sediment moved downcoast over the subsequent decades. The sediment stayed in a relatively continuous body—termed a coastal accretion wave—that extended 100's of meters offshore and several kilometers alongshore. The satellite measurements also allowed us to track the evolution of the shape and speed of this accretion wave and compare these results with physical conditions and sediment movement theory. Comparing with historical measurements, maps, and accounts, we hypothesize that sediment from the Klamath River has been a primary source of sediment to this coast, including the formation of the accretion wave and study area's broad beach. Key Points: An accretion wave of ∼20 million m3 of littoral sediment formed in the late 1980s and translated ∼15‐km downcoast over the next 30+ yearsAlongshore diffusion of the wave was less than predicted by theory, which is attributed to transport convergence from the shoreline curvatureIncreases in river sediment discharge from human impacts and climate extremes may have initiated the accretion wave [ABSTRACT FROM AUTHOR]

Onshore bar migration is a characteristic bar behavior during post‐storm beach recovery. The present large‐scale experiments, feature bichromatic wave groups over an initially steep (1:15), fully‐evolving beach. The same accretive wave condition is applied on two different post‐storm beach profiles featuring outer and inner bars. They are characterized by a larger (smaller) shoreline erosion and a larger (smaller) outer breaker bar located farther away from (closer to) the shoreline depending on the larger (smaller) energy of the storm condition. After a considerable post‐storm recovery time, similar equilibrium profiles are obtained, stressing the link between wave condition and equilibrium beach configuration. However, the evolution toward the equilibrium is different and depends on the initial morphological condition (post‐storm beach profile). After the larger storm, the morphological evolution is termed accretive merging (AM) and characterized by merging of the two bars (outer bar dissipation). After the smaller storm, the morphological evolution denoted as accretive non‐merging (AN) is characterized by onshore migration of the two bars with constant distance between them (bar maintenance). This study focuses on processes around the outer bar. During AN it features wave breaking, causing large suspended net offshore transport. AM, in contrast, mainly features bedload related to short wave asymmetries and low decomposed net transport rate magnitudes. High suspended net offshore transport occurs solely onshore of the outer bar trough. This causes filling of the bar trough and bar dissipation during migration. Additionally, processes around the outer bars are linked to accretion onshore of the bars and at the shoreline. Plain Language Summary: Nearshore sandbars are seabed features that protect coastal infrastructure behind many sandy beaches around the world. In response to waves they change in shape and distance to the beach, playing a key role in beach recovery after storms. To improve understanding of their onshore movement (migration), experiments were conducted which represented natural conditions in a controlled laboratory setting. In this context, the underwater transport of sand was measured. Application of the same recovery wave condition to two different post‐storm beach profiles resulted in two different types of bar onshore migration. After long experimental duration, both types evolved toward relatively similar beach profiles but the different ways of reaching them might have important practical consequences. In general, bar migration was governed by the interaction of onshore‐ and offshore‐transporting processes. They, in turn, were influenced by wave breaking. Bars, furthermore, cause wave breaking—closing the feedback loop. Ultimately, the different wave breaking locations, resulting from the shape of the post‐storm profiles, caused the different types of bar onshore migration during recovery. The present results provide crucial information for the development of mathematical models to forecast beach evolution and safeguard human interests in the coastal zone. Key Points: Accretive wave condition determines quasi‐equilibrium recovery beach profile irrespective of initial profilesConfiguration of post‐storm profiles determines type of accretive morphological evolution toward the quasi‐equilibrium profileOuter bar maintenance associated with wave breaking over the bar while breaking farther onshore leads to outer bar dissipation [ABSTRACT FROM AUTHOR]

Overwash is the cross‐shore transport of water and sediment from a waterbody over the crest of a sand or gravel barrier beach, and washover is the resulting sedimentary deposit. Washover volume, and alongshore patterns of washover distribution, are fundamental components of sediment budgets for low‐lying coastal barrier systems. Accurate sediment budgets are essential to forecasting barrier system sustainability under future climate‐driven forcing. However, comprehensive surveys of three‐dimensional washover morphology are challenging to deliver. Here, we use the results of a physical experiment, analysis of lidar data, and examples of washover characteristics reported in the literature to develop scaling relationships for washover morphometry that demonstrate volume can be reasonably inferred from planform measurements, for washover in natural (non‐built) and built barrier settings. Gaining three‐dimensional insight into washover deposits from two‐dimensional information unlocks the ability to analyze past aerial imagery and estimate contributions from washover flux to sediment budgets for past storms. Plain Language Summary: When a coastal storm drives water up and over the crest of a beach, sediment gets picked up by the flow and deposited behind the beach. That deposit, which might settle among dunes, on a marsh, or on the streets of a neighborhood, is called washover. Knowing the total volume of washover delivered by a storm event helps coastal managers account for the amount of sediment that moves through a beach system over time, known as a sediment budget. An accurate sediment budget provides an indication of environmental functioning and sustainability. However, washover volume is expensive to measure over large spatial scales—so despite its importance to sediment budgets, washover volume often goes unquantified. What if three‐dimensional washover volume could be estimated from the two‐dimensional shape and size of washover deposits visible in aerial photos? Here, we created washover deposits in a laboratory and compared them to washover in field settings to show that the area of a washover deposit is a good predictor of its volume. This relationship between area and volume unlocks information about past storm deposition captured in aerial photo archives, and enables estimation of washover volume where direct measurement of volume is unavailable or impossible. Key Points: Washover volume can be estimated from washover areaScaling relationships for washover size and shape link measurements from a physical experiment and field examplesEstimation of washover volume from aerial imagery is a step toward quantifying storm‐driven contributions to sediment budgets [ABSTRACT FROM AUTHOR]

Field measurements of aeolian sediment transport during major storm events are challenging in coastal settings due to the common coincidence of high winds with elevated water levels that can cover beaches. This work demonstrates a new application of lidar to remotely measure properties of wind‐blown sand transport at high spatial resolution. A data set of spatially continuous saltation heights was remotely developed from rapid (7.1 Hz) lidar scanning along a two‐dimensional transect across a beach during wind speeds of between 3.1 and 15.8 m/s associated with the passing of Tropical Storm Isaias. Outputs from the lidar demonstrate the ability to remotely observe the threshold velocity for the initiation of motion for sand transport and show that the upper limit of the saltation layer rises with increasing wind speed. Plain Language Summary: Wind can be an important contributor to landscape changes in sandy desert and coastal environments. There are complex mechanisms by which wind moves sand that are not yet entirely understood. To answer questions about how, when, and why sand is transported by wind, experiments commonly use point‐based sensors that are unable to capture the full spatial and temporal complexity of sand movement very close to the ground. This paper shows that new laser sensors can be utilized to remotely measure properties of sand transport simultaneously at multiple points and with increased detail compared to prior approaches. High resolution, remote measurements from a tropical storm event are used to show how high wind‐blown sand is lifted off of the ground surface and how different wind speeds influence these sand transport patterns. Key Points: Wind‐driven sand transport can be measured using repeat terrestrial laser scanningRemote measurements are used to characterize time and space variable saltation heights during energetic wind forcingMaximum saltation heights respond to changes in wind speed on a coastal beach [ABSTRACT FROM AUTHOR]

Shore platforms control wave energy transformation which, in turn, controls energy delivery to the cliff toe and nearshore sediment transport. Insight into shore platform erosion rates has conventionally been constrained at millimetre‐scales using micro‐erosion metres, and at metre‐scales using cartographic data. On apparently slowly eroding coasts, such approaches are fundamentally reliant upon long‐term observation to capture emergent erosion patterns. Where in practise timescales are short, and where change is either below the resolution or saturates the mode of measurement, the collection of data that enables the identification of the actual mechanisms of erosion is hindered. We developed a method to monitor shore platform erosion at millimetre resolution within metre‐scale monitoring plots using Structure‐from‐Motion photogrammetry. We conducted monthly surveys at 15 0.25 m2 sites distributed across the Hartle Loup platform in North Yorkshire, UK, over one year. We derived topographic data at 0.001 m resolution, retaining a vertical precision of change detection of 0.001 m. We captured a mean erosion rate of 0.528 mm yr‐1, but this varied considerably both across the platform and through the year. We characterized the volume and shape of eroded material. The detachment volume–frequency and shape distributions suggest that erosion happens primarily via removal of shale platelets. We identify that the at‐a‐point erosion rate can be predicted by the distance from the cliff and the tidal level, whereby erosion rates are higher closer to the cliff and at locations of higher tidal duration. The size of individual detachments is controlled by local micro‐topography and rock structure, whereby larger detachments are observed on more rough sections of the platform. Faster erosion rates and larger detachments occur in summer months, rather than in more energetic winter conditions. These results have the potential to form the basis of improved models of how platforms erode over both short‐ and long‐timescales. © 2019 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Sea stacks are common and striking coastal landforms, but few details are known about how, how quickly, and under what conditions they form. We present numerical and analytical models of sea stack formation due to preferential erosion along a pre-existing headland to address these basic questions. On sediment-rich rocky coasts, as sea cliffs erode and retreat, they produce beach sediment that is distributed by alongshore sediment transport and controls future sea cliff retreat rates. Depending on their width, beaches can encourage or discourage sea cliff erosion by acting either as an abrasive tool or a protective cover that dissipates wave energy seaward of the cliff. Along the flanks of rocky headlands where pocket beaches are often curved and narrow due to wave field variability, abrasion can accelerate alongshore-directed sea cliff erosion. Eventually, abrasion-induced preferential erosion can cut a channel through a headland, separating it from the mainland to become a sea stack. Under a symmetrical wave climate (i.e. equal influence of waves approaching the coastline from the right and from the left), numerical and analytical model results suggest that sea stack formation time and plan-view size are proportional to preferential erosion intensity (caused by, for example, abrasion and/or local rock weakness from joints, faults, or fractures) and initial headland aspect ratio, and that sea stack formation is discouraged when the sediment input from sea cliff retreat is too high (i.e. sea cliffs retreat quickly or are sand-rich). When initial headland aspect ratio is too small, and the headland is 'rounded' (much wider in the alongshore direction at its base than at its seaward apex), the headland is less conducive to sea stack formation. On top of these geomorphic and morphologic controls, a highly asymmetrical wave climate decreases sea stack size and discourages stack formation through rock-sediment interactions. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Prevailing ideas and calculations of coastal response to sea level rise (SLR) are often based on the Bruun model (Bruun P., Sea-level rise as a cause of shore erosion, Journal Waterways Harbors Division, ASCE 88: 117-130, 1962) that predicts upward and landward transfer of an equilibrium profile during SLR through offshore sediment transport on the shoreface. The model is based on a number of assumptions of questionable validity as well as outdated concepts on how sediment is transported across the shoreface. This contribution takes a numerical modelling approach that is based on first-order processes contributing to the movement of sediment across the shoreface. Using a wave transformation model that predicts hydrodynamic processes driving cross-shore sediment transport and an energetics-based model for the coupling between hydrodynamics and sediment transport, we show that cross-shore sediment transport is mainly onshore directed at the boundary between the lower and the upper shoreface, in agreement with the model proposed by Davidson-Arnott (Conceptual model of the effects of sea level rise on sandy coasts, Journal of Coastal Research 21: 1166-1172, 2005). The transition from onshore to offshore directed transport is located well within the surf zone and with a rising sea level this transition point becomes displaced landward and upward. Tests also show that substrate slope is of fundamental importance to the manner in which beaches react to rising sea level. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article discusses the bedload transport data from planebed and step pool reach types that are used to find out the grain size transport thresholds for chosen upland streams in southeast Australia. Structural deviation between the reach types let the effects of frictional losses from bedforms, microtopography and bed packing to be incorporated into the dimensionless critical shear stress value. Also included is a local sediment transport data in a regime model and applied to mountain streams to investigate whether empirical data improve the delineation of reach types on the basis of dimensionless discharge per unit width and dimensionless bedload transport.

This paper describes a new method for assessing aeolian fetch distances in beach/dune systems. The remote-sensing technique has advantages over currently used proxy measures of fetch distance, such as those based on tide gauges and beach profiles. The method uses a digital camera, global positioning system surveying, and a geographical information system software package to produce a rectified image of the beach surface. From this, direct measurements of the wet–dry beach boundary can be combined with wind direction measurements to determine fetch distance. The method offers an improvement on current approaches to sediment transport estimates: a 28-day study on Magilligan Strand, Northern Ireland, showed that the commonly used high water mark approach overestimated fetch distance by 30% compared with the technique reported here. [ABSTRACT FROM AUTHOR]