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Exploring Marine and Aeolian Controls on Coastal Foredune Growth Using a Coupled Numerical Model
Get PDFCoastal landscape change represents aggregated sediment transport gradients from spatially and temporally variable marine and aeolian forces. Numerous tools exist that independently simulate subaqueous and subaerial coastal profile change in response to these physical forces on a range of time scales. In this capacity, coastal foredunes have been treated primarily as wind-driven features. However, there are several marine controls on coastal foredune growth, such as sediment supply and moisture effects on aeolian processes. To improve understanding of interactions across the land-sea interface, here the development of the new Windsurf-coupled numerical modeling framework is presented. Windsurf couples standalone subaqueous and subaerial coastal change models to simulate the co-evolution of the coastal zone in response to both marine and aeolian processes. Windsurf is applied to a progradational, dissipative coastal system in Washington, USA, demonstrating the ability of the model framework to simulate sediment exchanges between the nearshore, beach, and dune for a one-year period. Windsurf simulations generally reproduce observed cycles of seasonal beach progradation and retreat, as well as dune growth, with reasonable skill. Exploratory model simulations are used to further explore the implications of environmental forcing variability on annual-scale coastal profile evolution. The findings of this work support the hypothesis that there are both direct and indirect oceanographic and meteorological controls on coastal foredune progradation, with this new modeling tool providing a new means of exploring complex morphodynamic feedback mechanisms
Is there a bulldozer in your model?
No full textDeliberate, real‐time human interventions into geomorphic processes are a phenomenon that no off‐the‐shelf numerical model of morphodynamics is built to capture. We suggest that active, responsive human processes that affect sediment transport during major storm events be included in evolving efforts to model geomorphic change
Data and morphometric results from a physical experiment simulating washover deposition
No full textThis portfolio includes two sets of data, used and explained in Lazarus, E. D., Williams, H. E., & Goldstein, E. B. (2022). Volume estimation from planform characteristics of washover morphology. Geophysical Research Letters, 49, e2022GL100098. https://doi.org/10.1029/2022GL100098:
1. washover morphometry measured from a physical experiment to simulate washover deposition, conducted at the Total Environment Simulator (TES) at the University of Hull ('TES_washover_morphometry.csv');
2. the terrestrial laser-scan data in which those morphometric characteristics of washover were measured ('Run01.zip' – 'Run22.zip'), with a table of experimental conditions for each trial (run).
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Dataset for "Thresholds in road network functioning on US Atlantic and Gulf barrier islands"
No full textThis dataset accompanies the paper "Thresholds in road network functioning on US Atlantic and Gulf barrier islands" (https://doi.org/10.31223/X55D1G) and is intended to be used to reproduce the analysis. In this dataset you can find the graphml files generated for each island (103 islands with drivable roads). Each intersection of the island road network is a node, and has an associated elevation and extreme water level value. Also included are the statistics for each network, and a single table with the analysis results for each of the networks with &gt;100 nodes.</span
Human–coastal coupled systems: ten questions
No full textGiven the inevitability of sea-level rise, investigating processes of human-altered coastlines at the intermediate timescales of years to decades can sometimes feel like an exercise in futility. Returning to the big picture and long view of feedbacks, emergent dynamics, and wider context, here we offer 10 existential questions for research into human–coastal coupled systems
Comparing patterns of hurricane washover into built and unbuilt environments
No full textExtreme geohazard events can change landscape morphology by redistributing huge volumes of sediment. Event-driven sediment deposition is typically studied in unbuilt settings – despite the ubiquity of occurrence and high economic cost of these geohazard impacts in built environments. Moreover, sedimentary consequences of extreme events in built settings tend to go unrecorded because they are rapidly cleared, at significant expense, from streets and roads to facilitate emergency response. Reducing disaster costs requires an ability to predict disaster impacts, which itself requires comprehensive measurement and study of the physical consequences of geohazard events. Here, using a database of poststorm aerial imagery, we measure plan-view geometric characteristics of sandy washover deposits in built and unbuilt settings following five different hurricane strikes along the Atlantic and Gulf Coasts of the US since 2011. We identify systematic similarities and differences between washover morphology in built and unbuilt environments, which we further explore with a simplified numerical model. Our findings suggest that spatial characteristics of the built environment (termed “fabric”) – specifically, the built fraction of the depositional zone – exerts a fundamental control on the form of large deposits. Accounting for the influence of built fabric on the morphodynamics of flow-driven geohazards is a tractable step toward improved forecasts of hazard impacts and disaster risk reduction.</p
Washover morphometry: lidar-derived and reported in literature
No full textThis portfolio includes three sets of data, used and explained in Lazarus, Williams & Goldstein (2022, https://doi.org/10.1029/2022GL100098):
1. washover morphometry measured from lidar-derived topographic change along the coastline of New Jersey, USA, following Hurricane Sandy (2012) ('NJ_Sandy_metrics.csv');
2. the geospatial data layers used to generate those measurements ('WashoverGIS.zip');
3. and a compilation of washover morphometry reported in the literature ('washover_LAV_literature_examples.csv').
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Data for 'Building back bigger in hurricane strike zones'
No full textThis data set accompanies the article 'Building back bigger in hurricane strike zones' (Lazarus et al., 2018).
In this repository we include footprint area of individual buildings measured from pairs of aerial photographs (taken 5–14 yrs apart) at five separate barrier-island locations along the US East and Gulf Coasts.
Table 1 lists the years in which the aerial images were taken, and the endpoint locations (latitude and longitude, in decimal degrees) for the sampled reaches at each site.
Table 2 lists the location name, a building ID, and the pre-storm and "final" 2017 footprint areas (in m2) measured from aerial images. (Note that the pre-storm image year is not the same for each location.)</span
Thresholds in road network functioning on US Atlantic and Gulf barrier islands
No full textBarrier islands predominate the Atlantic and Gulf coastlines of the USA, where population and infrastructure growth exceed national trends. Forward-looking models of barrier island dynamics often include feedbacks with real estate markets and management practices aimed at mitigating damage to buildings from natural hazards. However, such models thus far do not account for networks of infrastructure, such as roads, and how the functioning of infrastructure networks might influence management strategies. Understanding infrastructure networks on barrier islands is an essential step toward improved insight into the future dynamics of human-altered barriers. Here, we examine thresholds in the functioning of 72 US Atlantic and Gulf Coast barrier islands. We use digital elevation models to assign an elevation to each intersection in each road network. From each road network we sequentially remove intersections, starting from the lowest elevation. We use the maxima of the second giant connected component to identify a specific intersection—and corresponding elevation—at which functioning of the network fails, and we match the elevation of each critical intersection to local annual exceedance probabilities for extreme high-water levels. We find a range of failure thresholds for barrier island road network functioning, and also find that no single metric—absolute elevation, annual exceedance probability, or a quantitative metric of robustness—sufficiently ranks the susceptibility of barrier road networks to failure. Future work can incorporate thresholds for road network into forward-looking models of barrier island dynamics that include hazard-mitigation practices for protecting infrastructure
Volume Estimation From Planform Characteristics of Washover Morphology
Get PDFOverwash 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
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