Scholars@Duke
A. Brad Murray

A. Brad Murray

Professor of Geomorphology and Coastal Processes
Earth and Climate Sciences
abmurray@duke.edu
Box 90328, Duke University, Durham, NC 27708-0328
A318 LSRC, Duke University, Durham, NC 27708

Selected Publications

The Future of Developed Barrier Systems: 2. Alongshore Complexities and Emergent Climate Change Dynamics

Journal Article Earth's Future · April 1, 2024 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 stat ... Full text Cite

Islands on the move

Journal Article Nature Geoscience · August 1, 2022 Full text Open Access Cite

Wave-Climate Asymmetry Influence on Delta Evolution and River Dynamics

Journal Article Geophysical Research Letters · May 16, 2022 On wave-influenced river deltas, wave-driven sediment redistribution affects river progradation, and therefore avulsions, while avulsions change where sediment is delivered to the coastline, affecting coastline shape. Coastline shape, in turn, affects sedi ... Full text Cite

Discharge Determines Avulsion Regime in Model Experiments With Vegetated and Unvegetated Deltas

Journal Article Journal of Geophysical Research: Earth Surface · February 1, 2022 The dynamics and morphological evolution of deltas and their channel networks involve interactions between many factors, including water and sediment discharge and cohesion from fine sediment and vegetation. These interactions are likely to affect how stro ... Full text Cite

An Integrated, Probabilistic Modeling Approach to Assess the Evolution of Barrier-Island Systems Over the Twenty-First Century

Journal Article Frontiers in Marine Science · November 22, 2021 Barrier-island systems, spanning ∼7% of the world’s coastlines, are of great importance to society because not only they provide attractive, liveable space for coastal communities but also act as the first line of defense from coastal storms. As many of th ... Full text Cite

Dune Dynamics Drive Discontinuous Barrier Retreat

Journal Article Geophysical Research Letters · July 16, 2021 Barrier islands and spits tend to migrate landward in response to sea-level rise through the storm-driven process of overwash, but overwash flux depends on the height of the frontal dunes. Here, we explore this fundamental linkage between dune dynamics and ... Full text Cite

Twenty-first-century projections of shoreline change along inlet-interrupted coastlines.

Journal Article Scientific reports · July 2021 Sandy coastlines adjacent to tidal inlets are highly dynamic and widespread landforms, where large changes are expected due to climatic and anthropogenic influences. To adequately assess these important changes, both oceanic (e.g., sea-level rise) and terr ... Full text Open Access Cite

Competition Among Limestone Depressions Leads to Self-Organized Regular Patterning on a Flat Landscape

Journal Article Journal of Geophysical Research: Earth Surface · May 1, 2021 Self-organized pattern formation is widespread and functionally significant. Scale-dependent feedback in space (short-distance positive feedback coupled with long-distance negative feedback) has been embraced as an arguably universal mechanism of ecologica ... Full text Cite

Modeling long-term delta dynamics reveals persistent geometric river avulsion locations

Journal Article Earth and Planetary Science Letters · April 1, 2021 River deltas grow through repeated stacking of sedimentary lobes, the location and size of which are determined by channel avulsions (relatively sudden changes in river course). We use a model coupling fluvial and coastal processes to explore avulsion dyna ... Full text Open Access Cite

Probabilistic Application of an Integrated Catchment-Estuary-Coastal System Model to Assess the Evolution of Inlet-Interrupted Coasts Over the 21st Century

Journal Article Frontiers in Marine Science · December 16, 2020 Inlet-interrupted sandy coasts are dynamic and complex coastal systems with continuously evolving geomorphological behaviors under the influences of both climate change and human activities. These coastal systems are of great importance to society (e.g., p ... Full text Cite

A Holistic Modeling Approach to Project the Evolution of Inlet-Interrupted Coastlines Over the 21st Century

Journal Article Frontiers in Marine Science · July 10, 2020 Approximately one-quarter of the World’s sandy beaches, most of which are interrupted by tidal inlets, are eroding. Understanding the long-term (50–100 year) evolution of inlet-interrupted coasts in a changing climate is, therefore of great importance for ... Full text Cite

Watershed and ocean controls of salt marsh extent and resilience

Journal Article Earth Surface Processes and Landforms · May 1, 2020 The formation and evolution of tidal platforms are controlled by the feedbacks between hydrodynamics, geomorphology, vegetation, and sediment transport. Previous work mainly addresses dynamics at the scale of individual marsh platforms. Here, we develop a ... Full text Cite

Blind testing of shoreline evolution models.

Journal Article Scientific reports · February 2020 Beaches around the world continuously adjust to daily and seasonal changes in wave and tide conditions, which are themselves changing over longer time-scales. Different approaches to predict multi-year shoreline evolution have been implemented; however, ro ... Full text Cite

Impacts of Seagrass Dynamics on the Coupled Long-Term Evolution of Barrier-Marsh-Bay Systems

Journal Article Journal of Geophysical Research: Biogeosciences · February 1, 2020 Seagrass provides a wide range of economically and ecologically valuable ecosystem services, with shoreline erosion control often listed as a key service, but can also alter the sediment dynamics and waves within back-barrier bays. Here we incorporate seag ... Full text Cite

Correlation Between Shoreline Change and Planform Curvature on Wave-Dominated, Sandy Coasts

Journal Article Journal of Geophysical Research: Earth Surface · December 1, 2019 Low-lying, wave-dominated, sandy coastlines can exhibit high rates of shoreline change that may impact coastal infrastructure, habitation, recreation, and economy. Efforts to understand and quantify controls on shoreline change typically examine factors su ... Full text Cite

Ecohydrologic processes and soil thickness feedbacks control limestone-weathering rates in a karst landscape

Journal Article Chemical Geology · November 20, 2019 Chemical weathering of bedrock plays an essential role in the formation and evolution of Earth's critical zone. Over geologic time, the negative feedback between temperature and chemical weathering rates contributes to the regulation of Earth climate. The ... Full text Cite

Mass balance implies Holocene development of a low-relief karst patterned landscape

Journal Article Chemical Geology · November 20, 2019 We constructed mass balances of both calcium and phosphorus for two watersheds in Big Cypress National Preserve in southwest Florida (USA) to evaluate the time scales over which its striking landscape pattern developed. This low-relief carbonate landscape ... Full text Cite

Ecohydrologic feedbacks controlling sizes of cypress wetlands in a patterned karst landscape

Journal Article Earth Surface Processes and Landforms · April 1, 2019 Many landforms on Earth are profoundly influenced by biota. In particular, biota play a significant role in creating karst biogeomorphology, through biogenic CO 2 accelerating calcite weathering. In this study, we explore the ecohydrologic feedback mechani ... Full text Cite

Comparing the Cohesive Effects of Mud and Vegetation on Delta Evolution

Journal Article Geophysical Research Letters · October 16, 2018 Cohesive sediment exerts a significant influence on delta evolution, increasing shoreline rugosity and decreasing channel mobility. Vegetation has been assumed to play a similar role in delta evolution, but its cohesive effects have not been explicitly stu ... Full text Cite

Exploring wave and sea‐level rise effects on delta morphodynamics with a coupled river‐ocean model

Journal Article Journal of Geophysical Research. Earth Surface · October 11, 2018 Full text Link to item Cite

The role of ecomorphodynamic feedbacks and landscape couplings in influencing the response of barriers to changing climate

Chapter · February 15, 2018 Because barriers are low-lying and dynamic landforms, they are especially sensitive to changing environmental conditions. The continued existence of barriers will depend on the degree to which these landforms can maintain elevation above sea level while al ... Full text Cite

Barrier dynamics and response to changing climate

Book · February 15, 2018 This book presents chapters, written by leading coastal scientists, which collectively depict the current understanding of the processes that shape barrier islands and barrier spits, with an emphasis on the response of these landforms to changing condition ... Full text Cite

Geometric constraints on long-term barrier migration: From simple to surprising

Chapter · February 15, 2018 Considerations of mass conservation, sediment budgets, and geometry lead to insights regarding how barriers respond to sea-level rise. We begin with relatively simple insights, which facilitate more surprising conclusions as more complicated cases are cons ... Full text Cite

Downscaling Changing Coastlines in a Changing Climate: The Hybrid Approach

Journal Article Journal of Geophysical Research: Earth Surface · February 1, 2018 Shifts in the frequency of typical meteorological patterns in an ocean basin, over interannual to decadal time scales, cause shifts in the patterns of wave generation. Therefore, ocean basin-scale climate shifts produce shifts in the wave climates affectin ... Full text Cite

Effects of marsh edge erosion in coupled barrier island-marsh systems and geometric constraints on marsh evolution

Journal Article Journal of Geophysical Research: Earth Surface · January 1, 2018 Previous results show that overwash provides an important sediment source to back-barrier marshes, sustaining a narrow marsh state under conditions in which marsh drowning would otherwise occur. We expand the coupled barrier island-marsh evolution model GE ... Full text Cite

Modeling large-scale shoreline change caused by complex bathymetry in low-angle wave climates

Journal Article Marine Geology · January 1, 2017 Coastlines where waves consistently approach at highly oblique angles experience anti-diffusional behavior, causing perturbations to grow seaward and form sand waves, capes, and spits. Coasts where waves approach at low offshore angles experience the oppos ... Full text Cite

Complex coastlines responding to climate change: Do shoreline shapes reflect present forcing or "remember" the distant past?

Journal Article Earth Surface Dynamics · December 2, 2016 A range of planform morphologies emerge along sandy coastlines as a function of offshore wave climate. It has been implicitly assumed that the morphological response time is rapid compared to the timescales of wave climate change, meaning that coastal morp ... Full text Cite

Uncertainty quantification in modeling earth surface processes: More applicable for some types of models than for others

Journal Article Computers and Geosciences · May 1, 2016 In Earth-surface science, numerical models are used for a range of purposes, from making quantitatively accurate predictions for practical or scientific purposes ('simulation' models) to testing hypotheses about the essential causes of poorly understood ph ... Full text Cite

An evolving research agenda for human–coastal systems

Journal Article Geomorphology · March 2016 Full text Cite

Simulating mesoscale coastal evolution for decadal coastal management: A new framework integrating multiple, complementary modelling approaches

Journal Article Geomorphology · March 1, 2016 Coastal and shoreline management increasingly needs to consider morphological change occurring at decadal to centennial timescales, especially that related to climate change and sea-level rise. This requires the development of morphological models operatin ... Full text Cite

Appropriate complexity for the prediction of coastal and estuarine geomorphic behaviour at decadal to centennial scales

Journal Article Geomorphology · March 1, 2016 Coastal and estuarine landforms provide a physical template that not only accommodates diverse ecosystem functions and human activities, but also mediates flood and erosion risks that are expected to increase with climate change. In this paper, we explore ... Full text Cite

Exploring the sensitivities of crenulate bay shorelines to wave climates using a new vector-based one-line model

Journal Article Journal of Geophysical Research: Earth Surface · December 1, 2015 We use a new exploratory model that simulates the evolution of sandy coastlines over decadal to centennial timescales to examine the behavior of crenulate-shaped bays forced by differing directional wave climates. The model represents the coastline as a ve ... Full text Cite

The complex influences of back-barrier deposition, substrate slope and underlying stratigraphy in barrier island response to sea-level rise: Insights from the Virginia Barrier Islands, Mid-Atlantic Bight, U.S.A.

Journal Article Geomorphology · July 4, 2015 To understand the relative importance of back barrier environment, substrate slope and underlying stratigraphy in determining barrier island response to RSLR (relative sea-level rise), we use a morphological-behavior model (GEOMBEST) to conduct a series of ... Full text Cite

Forecasting the response of Earth's surface to future climatic and land use changes: A review of methods and research needs

Journal Article Earth's Future · July 1, 2015 In the future, Earth will be warmer, precipitation events will be more extreme, global mean sea level will rise, and many arid and semiarid regions will be drier. Human modifications of landscapes will also occur at an accelerated rate as developed areas i ... Full text Cite

Geoengineering Coastlines? From Accidental to Intentional

Chapter · June 10, 2015 On developed coastlines, humans react to physical processes in coastal environments by stabilizing shorelines against chronic erosion and by taking measures to prevent destruction of coastal infrastructure during storms. While we are beginning to understan ... Full text Cite

Recent shifts in coastline change and shoreline stabilization linked to storm climate change

Journal Article Earth Surface Processes and Landforms · April 1, 2015 Since cuspate coastlines are especially sensitive to changes in wave climate, they serve as potential indicators of initial responses to changing wave conditions. Previous work demonstrates that Cape Hatteras and Cape Lookout, North Carolina, which are lar ... Full text Cite

Sea stack formation and the role of abrasion on beach-mantled headlands

Journal Article Earth Surface Processes and Landforms · March 30, 2015 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 ... Full text Cite

Climate adaptation and policy-induced inflation of coastal property value.

Journal Article PloS one · January 2015 Human population density in the coastal zone and potential impacts of climate change underscore a growing conflict between coastal development and an encroaching shoreline. Rising sea-levels and increased storminess threaten to accelerate coastal erosion, ... Full text Open Access Cite

Modes and emergent time scales of embayed beach dynamics

Journal Article Geophysical Research Letters · October 28, 2014 In this study, we use a simple numerical model (the Coastline Evolution Model) to explore alongshore transport-driven shoreline dynamics within generalized embayed beaches (neglecting cross-shore effects). Using principal component analysis (PCA), we ident ... Full text Cite

Coastal vulnerability of a pinned, soft-cliff coastline - Part I: Assessing the natural sensitivity to wave climate

Journal Article Earth Surface Dynamics · June 3, 2014 The impact of future sea-level rise on coastal erosion as a result of a changing climate has been studied in detail over the past decade. The potential impact of a changing wave climate on erosion rates, however, is not typically considered. We explore the ... Full text Cite

Cause and effect in geomorphic systems: Complex systems perspectives

Journal Article Geomorphology · June 1, 2014 Applying complex systems perspectives to geomorphic systems leads to the conclusion that cause and effect in landscape systems does not always apply in the ways that common sense and traditional assumptions would suggest. Geomorphologists have long thought ... Full text Cite

Coastal vulnerability of a pinned, soft-cliff coastline, II: Assessing the influence of sea walls on future morphology

Journal Article Earth Surface Dynamics · April 23, 2014 Coastal defences have long been employed to halt or slow coastal erosion, and their impact on local sediment flux and ecology has been studied in detail through field research and numerical simulation. The non-local impact of a modified sediment flux regim ... Full text Cite

Data-driven components in a model of inner-shelf sorted bedforms: A new hybrid model

Journal Article Earth Surface Dynamics · January 28, 2014 Numerical models rely on the parameterization of processes that often lack a deterministic description. In this contribution we demonstrate the applicability of using machine learning, a class of optimization tools from the discipline of computer science, ... Full text Cite

Assessing ability to forecast geomorphic system responses to climate and land-use changes: Meeting of working group on the forecasting of landscape responses to climate and land-use changes; Tucson, Arizona; 24-28 September 2013

Journal Article Eos · January 7, 2014 As the global community faces the effects of ongoing and future climate and land-use changes (C&LUC), geoscientists are called to action to assess the risks associated with such changes, assist with forecasts of future Earth states, quantify hazards to lif ... Full text Cite

The shape of patterns to come: From initial formation to long-term evolution

Journal Article Earth Surface Processes and Landforms · January 1, 2014 Many studies focus on the emergence and development of rhythmic landscape patterns. In this contribution we explore the different behaviors found as patterns evolve; the trajectories that patterns exhibit as they transit from infinitesimal-amplitude pertur ... Full text Cite

Unraveling the dynamics that scale cross-shore headland relief on rocky coastlines: 2. Model predictions and initial tests

Journal Article Journal of Geophysical Research: Earth Surface · January 1, 2014 We explore the behavior of a theoretical model of cross-shore headland relief caused by alongshore differences in lithology and rock strength on rocky coastlines. Results address the question of why some rocky coasts exhibit frequent headland and embayment ... Full text Cite

Unraveling the dynamics that scale cross-shore headland relief on rocky coastlines: 1. Model development

Journal Article Journal of Geophysical Research: Earth Surface · January 1, 2014 We have developed an exploratory model of plan view, millennial-scale headland and bay evolution on rocky coastlines. Cross-shore coastline relief, or amplitude, arises from alongshore differences in sea cliff lithology, where durable, erosion-resistant ro ... Full text Cite

Prediction of wave ripple characteristics using genetic programming

Journal Article Continental Shelf Research · December 1, 2013 We integrate published data sets of field and laboratory experiments of wave ripples and use genetic programming, a machine learning paradigm, in an attempt to develop a universal equilibrium predictor for ripple wavelength, height, and steepness. We train ... Full text Cite

Observed changes in hurricane-driven waves explain the dynamics of modern cuspate shorelines

Journal Article Geophysical Research Letters · November 28, 2013 A comparison between historical and recent shoreline-change rates on the U.S. east coast (based on observed shoreline positions from the last century and a half) shows that emergent, large-scale, cuspate coastline features are changing shape, becoming more ... Full text Cite

Modeling emergent large-scale structures of barchan dune fields

Journal Article Geology · October 1, 2013 In nature, barchan dunes typically exist as members of larger fields that display striking, enigmatic structures that cannot be readily explained by examining the dynamics at the scale of single dunes, or by appealing to patterns in external forcing. To ex ... Full text Cite

Coupled economic-coastline modeling with suckers and free riders

Journal Article Journal of Geophysical Research: Earth Surface · June 1, 2013 Shoreline erosion is a natural trend along most sandy coastlines. Humans often respond to shoreline erosion with beach nourishment to maintain coastal property values. Locally extending the shoreline through nourishment alters alongshore sediment transport ... Full text Cite

Large-Scale Patterns in Hurricane-Driven Shoreline Change

Journal Article · April 3, 2013 The effects of storm events on cross-shore beach profiles have been the subject of concerted examination by nearshore researchers for decades. Because these investigations typically span relatively short (less than a kilometer) shoreline reaches, alongshor ... Full text Cite

Riparian Vegetation as a Primary Control on Channel Characteristics in Multi-Thread Rivers

Chapter · March 19, 2013 While many previous studies have explored the effects of vegetation on single-thread rivers, systematic studies on multi-thread rivers are scarce. Our approach is to synthesize data and ideas from a field-based study of the Waitaki River in New Zealand wit ... Full text Cite

The shape of patterns to come: From initial formation to long-term evolution

Journal Article Earth Surface Processes and Landforms · 2013 Cite

Instability and finite-amplitude self-organization of large-scale coastline shapes.

Journal Article Philos Trans A Math Phys Eng Sci · 2013 Recent research addresses the formation of patterns on sandy coastlines on alongshore scales that are large compared with the cross-shore extent of active sediment transport. A simple morphodynamic instability arises from the feedback between wave-driven a ... Full text Link to item Cite

Which Models Are Good (Enough), and When?

Journal Article · January 1, 2013 With the possible exception of some basic theories such as quantum mechanics and relativity, scientific models are by nature incorrect - at best they correspond to a natural system in limited ways. This is especially true of models used in Earth-surface-pr ... Full text Cite

Long-term, non-local coastline responses to local shoreline stabilization

Journal Article Geophysical Research Letters · October 16, 2012 The future of large-scale coastline evolution will be strongly coupled to human manipulations designed to prevent erosion. We explore the consequences of this coupling using a numerical model for large-scale coastline evolution to compare the long-term, no ... Full text Cite

Geometric scale invariance, genesis, and self-organization of polygonal fracture networks in granitic rocks

Journal Article Journal of Structural Geology · September 1, 2012 We documented polygonal fracture networks in the Tuolumne Intrusive Suite, Sierra Nevada Batholith by collecting data on the size, orientation, and length of fractures and fracture-bound polygons in nearly isotropic granitic rocks. Polygonal fracture netwo ... Full text Cite

Sorted bedform pattern evolution: Persistence, destruction and self-organized intermittency

Journal Article Geophysical Research Letters · December 28, 2011 We investigate the long-term evolution of inner continental shelf sorted bedform patterns. Numerical modeling suggests that a range of behaviors are possible, from pattern persistence to spatial-temporal intermittency. Sorted bedform persistence results fr ... Full text Cite

Emergent behavior in a coupled economic and coastline model for beach nourishment

Journal Article Nonlinear Processes in Geophysics · December 1, 2011 Developed coastal areas often exhibit a strong systemic coupling between shoreline dynamics and economic dynamics. "Beach nourishment", a common erosion-control practice, involves mechanically depositing sediment from outside the local littoral system onto ... Full text Cite

Beach and sea-cliff dynamics as a driver of long-term rocky coastline evolution and stability

Journal Article Geology · November 16, 2011 We investigate rocky coastline evolution over millennial time scales using exploratory analytical and numerical models based on interactions between beaches and sea cliffs. In the models, wave-driven sea-cliff retreat is a nonlinear function of beach width ... Full text Cite

Long-term, large-scale morphodynamic effects of artificial dune construction along a barrier island coastline

Journal Article Journal of Coastal Research · September 1, 2011 Interactions between human manipulations and landscape processes can form a dynamically coupled system because landscape-forming processes affect humans, and humans increasingly manipulate landscape-forming processes. Despite the dynamic nature of sandy ba ... Full text Cite

Quantification of fracture networks in non-layered, massive rock using synthetic and natural data sets

Journal Article Tectonophysics · June 3, 2011 Two quantitative measures - correlation dimension and maximum Lyapunov exponent - are investigated for quantifying fracture spacing in massive, non-layered rock. The correlation dimension, a measure of fractal dimension, characterizes some aspects of fract ... Full text Cite

Cumulative versus transient shoreline change: Dependencies on temporal and spatial scale

Journal Article Journal of Geophysical Research: Earth Surface · June 1, 2011 Using shoreline change measurements of two oceanside reaches of the North Carolina Outer Banks, USA, we explore an existing premise that shoreline change on a sandy coast is a self-affine signal, wherein patterns of change are scale invariant. Wavelet anal ... Full text Cite

Rapid wetland expansion during European settlement and its implication for marsh survival under modern sediment delivery rates

Journal Article Geology · May 1, 2011 Fluctuations in sea-level rise rates are thought to dominate the formation and evolution of coastal wetlands. Here we demonstrate a contrasting scenario in which land-use-related changes in sediment delivery rates drive the formation of expansive marshland ... Full text Cite

An integrated hypothesis for regional patterns of shoreline change along the Northern North Carolina Outer Banks, USA

Journal Article Marine Geology · March 15, 2011 Combining analyses of plan-view shoreline change and shoreline curvature with existing nearshore geologic and bathymetric data and the results of a recent theoretical, large-scale shoreline-evolution model that couples geologic framework to alongshore sedi ... Full text Cite

Progress in Coupling Models of Human and Coastal Landscape Change

Journal Article Computers & Geosciences · 2011 Cite

Large-scale responses of complex-shaped coastlines to local shoreline stabilization and climate change

Journal Article Journal of Geophysical Research: Earth Surface · September 1, 2010 When modeling the large-scale (> km) evolution of coastline morphology, the influence of natural forces is not the only consideration; ongoing direct human manipulations can substantially drive geomorphic change. In this paper, we couple a human component ... Full text Open Access Cite

The Value of Disappearing Beaches in North Carolina: A hedonic pricing model with endogenous beach width

Journal Article Journal of Environmental Economics and Management · 2010 Cite

Self-organized polygonal fracture networks in granitic rocks

Journal Article J. Structural Geology · 2010 Cite

Fetch-limited self-organization of elongate water bodies

Journal Article Geology · September 8, 2009 Naturally occurring elongate bodies that are segmented or appear to be in the process of segmentation occur in a variety of environments and scales. A simple, process-based numerical model of planform shoreline evolution demonstrates that fetch controls on ... Full text Cite

A unifying framework for shoreline migration: 2. Application to wave-dominated coasts

Journal Article Journal of Geophysical Research: Earth Surface · March 1, 2009 The Bruun rule, widely used to predict transgression due to sea level rise on decade to century timescales based on a fixed nearshore profile, neglects the influence of inland topography and substrate lithology, leading to physically unreasonable predictio ... Full text Cite

Geomorphology, complexity, and the emerging science of the Earth's surface

Journal Article Geomorphology · February 1, 2009 The following is a white paper (adapted here for print) for the U.S. National Research Council's committee on Challenges and Opportunities in Earth Surface Processes, drafted at a National Science Foundation sponsored workshop associated with the 38th Bing ... Full text Cite

Giant aeolian dune size determined by the average depth of the atmospheric boundary layer.

Journal Article Nature · February 2009 Depending on the wind regime, sand dunes exhibit linear, crescent-shaped or star-like forms resulting from the interaction between dune morphology and sand transport. Small-scale dunes form by destabilization of the sand bed with a wavelength (a few tens o ... Full text Cite

Beach nourishment as a dynamic capital accumulation problem

Journal Article Journal of Environmental Economics and Management · 2009 Beach nourishment is a common coastal management strategy used to combat erosion along sandy coastlines. It involves building out a beach with sand dredged from another location. This paper develops a positive model of beach nourishment and generates testa ... Full text Cite

Tidal marshes as disequilibrium landscapes? Lags between morphology and Holocene sea level change

Journal Article Geophysical Research Letters · December 28, 2008 Historical acceleration in the rate of global sea level rise and recent observations of marsh degradation highlight the importance of understanding how marshes respond to sea level change. Here, we use an existing numerical model to demonstrate that marsh ... Full text Cite

KEYNOTE: Biomorphodynamics in river, coastal and estuarine settings

Journal Article River, Coastal and Estuarine Morphodynamics: RCEM 2007 - Proceedings of the 5th IAHR Symposium on River, Coastal and Estuarine Morphodynamics · December 1, 2008 Populations of plants and animals affect sediment transport and morphological evolution in many environments. The term 'ecogeomorphology' (or 'biogeomorphology') describes studies that address such effects. In this selective review we use the term 'biomorp ... Cite

Biomorphodynamics: Physical-biological feedbacks that shape landscapes

Journal Article Water Resources Research · November 1, 2008 Plants and animals affect morphological evolution in many environments. The term "ecogeomorphology" describes studies that address such effects. In this opinion article we use the term "biomorphodynamics" to characterize a subset of ecogeomorphologic studi ... Full text Cite

Temporary vegetation disturbance as an explanation for permanent loss of tidal wetlands

Journal Article Geophysical Research Letters · March 16, 2008 Coastal ecosystems respond to sea level and sediment supply change according to complex, three-way interactions between vegetation, hydrology, and sediment transport. While biogeomorphic feedbacks preserve the morphology of intertidal surfaces covered by m ... Full text Cite

Ecological and morphological response of brackish tidal marshland to the next century of sea level rise: Westham Island, British Columbia

Journal Article Global and Planetary Change · February 1, 2008 In response to climatic warming, eustatic sea level has been predicted to rise by about 50 cm in the next century. While feedbacks between vegetation growth and sediment deposition tend to allow marshes to maintain their morphology under a constant rate of ... Full text Cite

Influence of "defects" on sorted bedform dynamics

Journal Article Geophysical Research Letters · January 28, 2008 Bedforms with plan-view patterns consisting of long crests interrupted by defects occur ubiquitously in subaqueous and subaerial environments where they strongly influence flows and sediment transport. We explore how such patterns adjust to changes in the ... Full text Cite

Shoreline migration—a unifying framework

Journal Article J Geophys Res · 2008 Cite

Coastline responses to human shoreline stabilization

Journal Article J Geophys Res · 2008 Cite

Preface: Complexity (and simplicity) in landscapes

Journal Article Geomorphology · November 1, 2007 Full text Cite

Patterns in the sand: From forcing templates to self-organization

Journal Article Geomorphology · November 1, 2007 The nearshore region exhibits many striking morphological patterns with a variety of spatial and temporal scales. The formation of these rhythmic features has been initially ascribed, depending on the pattern in question, to spatial structures in the flow ... Full text Cite

Process signatures in regional patterns of shoreline change on annual to decadal time scales

Journal Article Geophysical Research Letters · October 16, 2007 Gradients in wave-driven alongshore sediment transport influence the morphologies of sediment-covered coastlines on a range of spatial and temporal scales, affecting accretion and erosion patterns relevant to human development. Recent theoretical findings ... Full text Cite

Reducing model complexity for explanation and prediction

Journal Article Geomorphology · October 15, 2007 Numerical models can be useful for explaining poorly understood phenomena or for reliable quantitative predictions. When modeling a multi-scale system, a 'top-down' approach-basing models on emergent variables and interactions, rather than explicitly on th ... Full text Cite

Two paradigms in landscape dynamics: Self-similar processes and emergence

Chapter · September 25, 2007 This volume is comprised of the proceedings of "20 Years of Nonlinear Dynamics in Geosciences", held June 11-16, 2006 in Rhodes, Greece as part of the Aegean Conferences. ... Cite

Sorted bed forms as self-organized patterns: 2. Complex forcing scenarios

Journal Article Journal of Geophysical Research: Earth Surface · September 24, 2007 We employ a numerical model to study the development of sorted bed forms under a variety of hydrodynamic and sedimentary conditions. Results indicate that increased variability in wave height decreases the growth rate of the features and can potentially gi ... Full text Cite

Sorted bed forms as self-organized patterns: 1. Model development

Journal Article Journal of Geophysical Research: Earth Surface · September 24, 2007 Here we present a modified version of the exploratory numerical model originally presented by Murray and Thieler (2004) and use it to further investigate the development of sorted bed forms on the inner continental shelf. The new version of the model is ba ... Full text Cite

The response of spit shapes to wave-angle climates

Journal Article Coastal Sediments '07 - Proceedings of 6th International Symposium on Coastal Engineering and Science of Coastal Sediment Processes · September 17, 2007 We investigate spit formation and evolution in light of the high-wave-angle instability in shoreline shape arising from a maximizing angle for wave-driven alongshore sediment transport. Single spits emerge in a simple one-contour line numerical model that ... Full text Cite

Variable shoreline responses to sea-level rise and climate change

Journal Article Coastal Sediments '07 - Proceedings of 6th International Symposium on Coastal Engineering and Science of Coastal Sediment Processes · September 17, 2007 Researchers and coastal managers are addressing how climate change will affect shorelines. Important questions include: How far will a sandy shoreline retreat as sea level rise accelerates? And, how far landward will the effects of possibly intensified sto ... Full text Cite

The influence of tidal prism and vegetation on tidal channel morphology: Implications for Marsh stability

Journal Article Coastal Sediments '07 - Proceedings of 6th International Symposium on Coastal Engineering and Science of Coastal Sediment Processes · September 17, 2007 A peculiar feature of tidal channel networks is that their geometry (e.g. channel length, width, density) scales better with watershed area than tidal prism. Platform elevation has little control on network morphology, suggesting that relative platform dee ... Full text Cite

An alternative explanation for the shape of 'log-spiral' bays

Journal Article Coastal Sediments '07 - Proceedings of 6th International Symposium on Coastal Engineering and Science of Coastal Sediment Processes · September 17, 2007 We present a simple numerical model capable of producing distinctive scalloped bays of a form found when a sandy coastline extends downdrift of a rocky headland. The shape of such bays can often be approximated by a log-spiral - a curve for which the radiu ... Full text Cite

Sensitivity analysis of pediment development through numerical simulation and selected geospatial query

Journal Article Geomorphology · August 1, 2007 Dozens of references recognizing pediment landforms in widely varying lithologic, climatic, and tectonic settings suggest a ubiquity in pediment forming processes on mountain piedmonts worldwide. Previous modeling work illustrates the development of a uniq ... Full text Cite

A coupled geomorphic and ecological model of tidal marsh evolution.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · April 2007 The evolution of tidal marsh platforms and interwoven channel networks cannot be addressed without treating the two-way interactions that link biological and physical processes. We have developed a 3D model of tidal marsh accretion and channel network deve ... Full text Cite

Twenty years of nonlinear dynamics in geosciences

Journal Article Eos · January 16, 2007 Full text Cite

The role of hydrodynamic forcing in the development of "sorted bedforms"

Journal Article Proceedings of the Coastal Engineering Conference · January 1, 2007 The development of sorted bedforms on the inner shelf has been simulated using a modified version of the model originally developed by Murray and Thieler (1994). The model is here used to analyze the effect of hydrodynamics on the emergent characteristics ... Full text Cite

High-angle wave instability and emergent shoreline shapes: 1. Modeling of sand waves, flying spits, and capes

Journal Article Journal of Geophysical Research: Earth Surface · December 24, 2006 Contrary to traditional findings, the deepwater angle of wave approach strongly affects plan view coastal evolution, giving rise to an antidiffusional "high wave angle" instability for sufficiently oblique deepwater waves (with angles between wave crests a ... Full text Cite

High-angle wave instability and emergent shoreline shapes: 2. Wave climate analysis and comparisons to nature

Journal Article Journal of Geophysical Research: Earth Surface · December 24, 2006 Recent research has revealed that the plan view evolution of a coast due to gradients in alongshore sediment transport is highly dependant upon the angles at which waves approach the shore, giving rise to an instability in shoreline shape that can generate ... Full text Cite

Different approaches to modeling inner-shelf 'sorted bedforms'

Journal Article River, Coastal and Estuarine Morphodynamics: RCEM 2005 - Proceedings of the 4th IAHR Symposium on River, Coastal and Estuarine Morphodynamics · December 1, 2006 A previous investigation of large-scale grain-size sorted patterns on inner continental shelves used an exploratory numerical model that represented with simple parameterizations what was hypothesized to be a key relationship between grain size and bottom ... Cite

Delta simulations using a one-line model coupled with overwash

Journal Article Coastal Dynamics 2005 - Proceedings of the Fifth Coastal Dynamics International Conference · December 1, 2006 By adding a simple fixed-point sediment source to a numerical one-contour-line coastal evolution model, we investigate how the distribution of wave approach angles affects the evolution of wave-dominated deltas. These experiments are motivated by recent fi ... Full text Cite

Investigating shoreface-lithology effects in a process-based model of coastline change

Journal Article Coastal Dynamics 2005 - Proceedings of the Fifth Coastal Dynamics International Conference · December 1, 2006 We have developed a numerical model that couples geologic framework effects and alongshore sediment transport processes to investigate large-scale, long-term shoreline evolution in sediment-limited environments. Shoreline segments underlain by material com ... Full text Cite

Response of an ecomorphodynamic model of tidal marshes to varying sea level rise rates

Journal Article River, Coastal and Estuarine Morphodynamics: RCEM 2005 - Proceedings of the 4th IAHR Symposium on River, Coastal and Estuarine Morphodynamics · December 1, 2006 We have developed a numerical model of tidal marsh accretion and channel network development that couples physical sediment processes with vegetation productivity. We have previously demonstrated that under a constant rate of sea level rise, the marsh plat ... Cite

Emergence of pediments, tors, and piedmont junctions from a bedrock weathering-regolith thickness feedback

Journal Article Geology · October 1, 2006 Sediment erosion laws form the basis for most landscape evolution models and guide geomorphologists in the pursuit of understanding how landscapes evolve. This focus on the alluvial surface, however, ignores the role of intrinsic feedbacks between sediment ... Full text Cite

Coastline responses to changing storm patterns

Journal Article Geophysical Research Letters · September 28, 2006 Researchers and coastal managers are pondering how accelerated sea-level rise and possibly intensified storms will affect shorelines. These issues are most often investigated in a cross-shore profile framework, fostering the implicit assumption that coastl ... Full text Cite

Regolith thickness instability and the formation of tors in arid environments

Journal Article Journal of Geophysical Research: Earth Surface · September 24, 2006 We present model results suggesting that a physical erosion-bedrock weathering feeback is responsible for the development of isolated bedrock knobs (tors/inselbergs) that often punctuate otherwise smooth pediments of homogeneous basement lithology. Tors an ... Full text Cite

How does underlyng geology affect coastline change? An initial modeling investigation

Journal Article Journal of Geophysical Research: Earth Surface · June 24, 2006 Conceptual geologic framework models predict that areas of the coast underlain by a weak or very fine grained lithology retreat landward faster than adjacent, more resistant or coarser-grained segments. These apparently commonsense predictions seem inconsi ... Full text Cite

Fluvial and marine controls on combined subaerial and subaqueous delta progradation: Morphodynamic modeling of compound-clinoform development

Journal Article Journal of Geophysical Research: Earth Surface · June 1, 2005 Fluviodeltaic systems commonly display a compound-clinoform geometry that consists of a subaerial/subaqueous delta couplet. The extent of subaqueous delta development varies significantly and, in modern systems, is a function of fluvial input and basin hyd ... Full text Cite

Extending a 1-line modeling approach to explore emergent coastline behaviors

Conference Proceedings of the Coastal Engineering Conference · April 1, 2005 Previous work treating shoreline change arising from alongshore sediment transport as a diffusion of shoreline shape has been in error. When the effects of nearshore refraction on breaking-wave characteristics are included, analyses show that shoreline dif ... Full text Cite

Rip currents due to wave-current interaction

Chapter · January 1, 2005 In this linear instability study, we examine the incipience of depth averaged circulations, which are related to rip currents in the surf zone, due to interactions of waves and currents on alongshore uniform beaches. We consider normally incident waves, su ... Full text Cite

Rip channel development on nonbarred beaches: The importance of a lag in suspended-sediment transport

Journal Article Journal of Geophysical Research: Oceans · April 15, 2004 On approximately planar beaches, rip channel development is often preceded by a period in which jet-like rip currents develop in apparently random locations, and dissipate after Minutes to tens of minutes. The subsequent development of sharp-edged, trough- ... Full text Cite

Modeling rip channel development

Journal Article Journal of Geophysical Research · 2004 Cite

A new hypothesis and exploratory model for the formation of large-scale inner-shelf sediment sorting and "rippled scour depressions"

Journal Article Continental Shelf Research · January 1, 2004 Recent observations of inner continental shelves in many regions show numerous collections of relatively coarse sediment, which extend kilometers in the cross-shore direction and are on the order of 100m wide. These "rippled scour depressions" have been in ... Full text Cite

Tests of a new hypothesis for non-bathymetrically driven rip currents

Journal Article Journal of Coastal Research · March 1, 2003 Rip currents - strong, isolated, offshore-directed flows - can occur in the absence of bathymetric features such as rip channels. No consensus exists regarding the cause of these impressive but life-threatening features, sometimes called "flash" rip curren ... Cite

Modelling the effect of vegetation on channel pattern in bedload rivers

Journal Article Earth Surface Processes and Landforms · February 1, 2003 We modify a simple numerical stream-pattern model to examine the effect of sediment stabilization by roots on the channel pattern of bedload rivers. In the model, vegetation enhances bank resistance to erosion, causing the development of a single channel i ... Full text Cite

Formation of coastline features by large-scale instabilities induced by high-angle waves.

Journal Article Nature · November 2001 Along shore sediment transport that is driven by waves is generally assumed to smooth a coastline. This assumption is valid for small angles between the wave crest lines and the shore, as has been demonstrated in shoreline models. But when the angle betwee ... Full text Cite

A model for sorted circles as self-organized patterns

Journal Article Journal of Geophysical Research: Solid Earth · July 10, 2001 Sorted circles emerge as self-organized patterns from a laterally uniform active layer that becomes laterally sorted as frost heave deforms the interface between a stone layer and an underlying soil layer. In a three-dimensional, cellular model of the acti ... Full text Cite

A model for sorted circles as self-organized patterns

Journal Article Journal of Geophysical Research · 2001 Cite

From strange attractors to real-world data: Evaluating a bedform model by measuring the distance between state-space plots

Journal Article Mathematical Geology · January 1, 2001 A new nonlinear data-analysis technique compares the typical sequences in different time or spatial series. The method quantitatively compares delay-coordinate embedded state-space plots by treating them plots as probability distributions. Thus its applica ... Full text Cite

A rip current model based on a hypothesized wave/current interaction

Journal Article Journal of Coastal Research · January 1, 2001 What causes strong, focused rip currents to develop on planar beaches? Observations of waves in the presence of rip currents suggest an interaction between waves and currents that causes wave dissipation. A hypothesized mechanism that would cause such an i ... Cite

Validation of braided-stream models: Spatial state-space plots, self-affine scaling, and island shapes

Journal Article Water Resources Research · September 1, 1998 We present a comprehensive approach for validating braided-stream models and apply it to a specific cellular braided-stream model. The approach involves quantitative comparison of modeled and natural braided streams in terms of two main aspects: the sequen ... Full text Cite

Properties of a cellular braided-stream model

Journal Article Earth Surface Processes and Landforms · January 1, 1997 We have shown in a previous paper that many of the main features of braided streams can be captured in a relatively simple cellular computer model. Here we examine some of the detailed characteristics of this model. We show the qualitative form of the brai ... Full text Cite

Measuring the distance between time series

Journal Article Physica D: Nonlinear Phenomena · January 1, 1997 To evaluate models of dynamical systems, researchers have traditionally used quantitative measures of short term prediction errors. However, for chaotic or stochastic systems, comparison of long term, qualitative behaviors may be more relevant. Let x = (x0 ... Full text Cite

A new quantitative test of geomorphic models, applied to a model of braided streams

Journal Article Water Resources Research · August 1, 1996 Recent simple cellular models of self-organized geomorphic patterns embody a new understanding of complex, spatially extended systems. Such models can be difficult to test quantitatively because the statistics traditionally used can be insensitive even to ... Full text Cite

Estimation of discharge from three braided rivers using synthetic aperture radar satellite imagery: Potential application to ungaged basins

Journal Article Water Resources Research · July 1, 1996 Analysis of 41 ERS 1 synthetic aperture radar images and simultaneous ground measurements of discharge for three large braided rivers indicates that the area of active flow on braided river floodplains is primarily a function of discharge. A power law corr ... Full text Cite

A cellular model of braided rivers

Journal Article Nature · January 1, 1994 A broad sheet of water flowing over non-cohesive sediment typically breaks up into a network of interconnected channels called a braided stream (Fig. 1). The dynamics of such networks are complex; channels migrate laterally, split, rejoin and develop bars, ... Full text Cite