Articles | Volume 9, issue 1
Research article 08 Jan 2021
Research article | 08 Jan 2021
Groundwater erosion of coastal gullies along the Canterbury coast (New Zealand): a rapid and episodic process controlled by rainfall intensity and substrate variability
Aaron Micallef et al.
No articles found.
Chris Houser, Jacob Lehner, Nathan Cherry, and Phil Wernette
Nat. Hazards Earth Syst. Sci., 19, 2541–2549,Short summary
On many beaches, lifeguards set out flags to warn beach users of the surf and rip hazard based on the regional surf forecast and careful observation. There is a potential that the chosen flag does not accurately reflect the potential risk. Results of a machine learning analysis suggest that the greatest number of rescues occurred on days when the lifeguard flew a more cautious flag than the model predicted. It is argued that that beach users may be discounting lifeguard warnings.
Phillipe A. Wernette, Chris Houser, Bradley A. Weymer, Mark E. Everett, Michael P. Bishop, and Bobby Reece
Earth Surf. Dynam., 6, 1139–1153,Short summary
Barrier islands change through time and space in response to natural and human forces. This paper shows that barrier island development and the beach–dune system can be influenced asymmetrically during island development by ancient and buried river valleys that cross the modern barrier island. Given the importance of the natural environment, coastal management projects should first seek to understand how the island developed in order to more effectively balance natural and human pressure.
Denis Cohen, Fabien Gillet-Chaulet, Wilfried Haeberli, Horst Machguth, and Urs H. Fischer
The Cryosphere, 12, 2515–2544,Short summary
As part of an integrative study about the safety of repositories for radioactive waste under ice age conditions in Switzerland, we modeled the flow of ice of the Rhine glacier at the Last Glacial Maximum to determine conditions at the ice–bed interface. Results indicate that portions of the ice lobes were at the melting temperature and ice was sliding, two conditions necessary for erosion by glacier. Conditions at the bed of the ice lobes were affected by climate and also by topography.
Bradley A. Weymer, Phillipe Wernette, Mark E. Everett, and Chris Houser
Earth Surf. Dynam., 6, 431–450,Short summary
This research presents a new method for quantifying the geologic controls on modern barrier island evolution. We used statistical time series analysis to evaluate the scale-dependent vs. scale-independent behavior of a barrier island in southern Texas, USA. By integrating subsurface geophysical with surface geomorphological measurements, we show that the island exhibits both free and forced evolutionary behavior that has important implications for how the island may respond to rising sea levels.
Denis Cohen and Massimiliano Schwarz
Earth Surf. Dynam., 5, 451–477,Short summary
Tree roots reinforce soils on slopes. A new slope stability model is presented that computes root reinforcement including the effects of root heterogeneities and dependence of root strength on tensile and compressive strain. Our results show that roots stabilize slopes that would otherwise fail under a rainfall event. Tension in roots is more effective than compression. Redistribution of forces in roots across the hillslope plays a key role in the stability of the slope during rainfall events.
F. Giadrossich, M. Niedda, D. Cohen, and M. Pirastru
Hydrol. Earth Syst. Sci., 19, 2451–2468,
Related subject area
Physical: Landscape Evolution: modelling and field studiesErosional response of granular material in landscape modelsTransport-limited fluvial erosion – simple formulation and efficient numerical treatmentDimensional analysis of a landscape evolution model with incision thresholdComputing water flow through complex landscapes – Part 2: Finding hierarchies in depressions and morphological segmentationsRivers as linear elements in landform evolution modelsInteractions between main channels and tributary alluvial fans: channel adjustments and sediment-signal propagationDrainage divide networks – Part 1: Identification and ordering in digital elevation modelsDrainage divide networks – Part 2: Response to perturbationsHillslope denudation and morphologic response to a rock uplift gradientGeomorphic signatures of the transient fluvial response to tiltingThe destiny of orogen-parallel streams in the Eastern Alps: the Salzach–Enns drainage systemStatistical modelling of co-seismic knickpoint formation and river response to fault slipA versatile, linear complexity algorithm for flow routing in topographies with depressionsCan the growth of deltaic shorelines be unstable?Development of proglacial lakes and evaluation of related outburst susceptibility at the Adygine ice-debris complex, northern Tien ShanReconstruction of four-dimensional rockfall trajectories using remote sensing and rock-based accelerometers and gyroscopesShort communication: flow as distributed lines within the landscapeMorphological effects of vegetation on the tidal–fluvial transition in Holocene estuariesScaling and similarity of a stream-power incision and linear diffusion landscape evolution modelA lattice grain model of hillslope evolutionOn the Holocene evolution of the Ayeyawady megadeltaNumerical modelling of landscape and sediment flux response to precipitation rate changeDeveloping and exploring a theory for the lateral erosion of bedrock channels for use in landscape evolution modelsLandscape evolution models using the stream power incision model show unrealistic behavior when m ∕ n equals 0.5Late Holocene evolution of a coupled, mud-dominated delta plain–chenier plain system, coastal Louisiana, USADistinct phases of eustatic and tectonic forcing for late Quaternary landscape evolution in southwest Crete, Greece10Be systematics in the Tsangpo-Brahmaputra catchment: the cosmogenic nuclide legacy of the eastern Himalayan syntaxisQuantifying uncertainty in high-resolution remotely sensed topographic surveys for ephemeral gully channel monitoringPhysical theory for near-bed turbulent particle suspension capacityAutogenic versus allogenic controls on the evolution of a coupled fluvial megafan–mountainous catchment system: numerical modelling and comparison with the Lannemezan megafan system (northern Pyrenees, France)Accurate simulation of transient landscape evolution by eliminating numerical diffusion: the TTLEM 1.0 modelThe sensitivity of landscape evolution models to spatial and temporal rainfall resolutionGravel threshold of motion: a state function of sediment transport disequilibrium?The influence of Holocene vegetation changes on topography and erosion rates: a case study at Walnut Gulch Experimental Watershed, ArizonaBedrock incision by bedload: insights from direct numerical simulationsModelling sediment clasts transport during landscape evolutionBasal shear stress under alpine glaciers: insights from experiments using the iSOSIA and Elmer/Ice modelsExperimental migration of knickpoints: influence of style of base-level fall and bed lithologyThe periglacial engine of mountain erosion – Part 1: Rates of frost cracking and frost creepThe periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolutionBedload transport controls bedrock erosion under sediment-starved conditionsIce flow models and glacial erosion over multiple glacial–interglacial cyclesMacro-roughness model of bedrock–alluvial river morphodynamicsA reduced-complexity model for river delta formation – Part 1: Modeling deltas with channel dynamicsA reduced-complexity model for river delta formation – Part 2: Assessment of the flow routing schemeNeotectonics, flooding patterns and landscape evolution in southern AmazoniaMorphodynamics of river bed variation with variable bedload step lengthA two-sided approach to estimate heat transfer processes within the active layer of the Murtèl–Corvatsch rock glacierAnalysis of the drainage density of experimental and modelled tidal networksOpportunities from low-resolution modelling of river morphology in remote parts of the world
Riccardo Reitano, Claudio Faccenna, Francesca Funiciello, Fabio Corbi, and Sean D. Willett
Earth Surf. Dynam., 8, 973–993,Short summary
Looking into processes that occur on different timescales that span over thousands or millions of years is difficult to achieve. This is the case when we try to understand the interaction between tectonics and surface processes. Analog modeling is an investigating technique that can overcome this limitation. We study the erosional response of an analog landscape by varying the concentration of components of analog materials that strongly affect the evolution of experimental landscapes.
Earth Surf. Dynam., 8, 841–854,Short summary
Many contemporary models of large-scale fluvial erosion focus on the detachment-limited regime where all material entrained by the river is immediately excavated. This limitation facilitates the comparison with real river profiles and strongly reduces the numerical complexity. Here a simple formulation for the opposite case, transport-limited erosion, and a new numerical scheme that achieves almost the same numerical efficiency as detachment-limited models are presented.
Nikos Theodoratos and James W. Kirchner
Earth Surf. Dynam., 8, 505–526,Short summary
We non-dimensionalized a commonly used model of landscape evolution that includes an incision threshold. Whereas the original model included four parameters, we obtained a dimensionless form with a single parameter, which quantifies the relative importance of the incision threshold. Working with this form saves computational time and simplifies theoretical analyses.
Richard Barnes, Kerry L. Callaghan, and Andrew D. Wickert
Earth Surf. Dynam., 8, 431–445,Short summary
Maps of elevation are used to help predict the flow of water so we can better understand landslides, floods, and global climate change. However, modeling the flow of water is difficult when elevation maps include swamps, lakes, and other depressions. This paper explains a new method that overcomes these difficulties, allowing models to run faster and more accurately.
Earth Surf. Dynam., 8, 367–377,Short summary
Models of fluvial erosion have a long history in landform evolution modeling. Interactions between rivers and processes acting at hillslopes (e.g., landslides) are receiving growing interest in this context. While present-day computer capacities allow for applying such coupled models, there is still a scaling problem when considering rivers to be linear elements on a topography. Based on a reinterpretation of old empirical results, this study presents a new approach to overcome this problem.
Sara Savi, Stefanie Tofelde, Andrew D. Wickert, Aaron Bufe, Taylor F. Schildgen, and Manfred R. Strecker
Earth Surf. Dynam., 8, 303–322,Short summary
Fluvial deposits record changes in water and sediment supply. As such, they are often used to reconstruct the tectonic or climatic history of a basin. In this study we used an experimental setting to analyze how fluvial deposits register changes in water or sediment supply at a confluence zone. We provide a new conceptual framework that may help understanding the construction of these deposits under different forcings conditions, information crucial to correctly inferring the history of a basin.
Dirk Scherler and Wolfgang Schwanghart
Earth Surf. Dynam., 8, 245–259,Short summary
Drainage divides are believed to provide clues about divide migration and the instability of landscapes. Here, we present a novel approach to extract drainage divides from digital elevation models and to order them in a drainage divide network. We present our approach by studying natural and artificial landscapes generated with a landscape evolution model and disturbed to induce divide migration.
Dirk Scherler and Wolfgang Schwanghart
Earth Surf. Dynam., 8, 261–274,Short summary
Drainage divides are believed to provide clues about divide migration and the instability of landscapes. Here, we present a novel approach to extract drainage divides from digital elevation models and to order them in a drainage divide network. We present our approach by studying natural and artificial landscapes generated with a landscape evolution model and disturbed to induce divide migration.
Vincent Godard, Jean-Claude Hippolyte, Edward Cushing, Nicolas Espurt, Jules Fleury, Olivier Bellier, Vincent Ollivier, and the ASTER Team
Earth Surf. Dynam., 8, 221–243,Short summary
Slow-slipping faults are often difficult to identify in landscapes. Here we analyzed high-resolution topographic data from the Valensole area at the front of the southwestern French Alps. We measured various properties of hillslopes such as their relief and the shape of hilltops. We observed systematic spatial variations of hillslope morphology indicative of relative changes in erosion rates. These variations are potentially related to slow tectonic deformation across the studied area.
Helen W. Beeson and Scott W. McCoy
Earth Surf. Dynam., 8, 123–159,Short summary
We used a computer model to show that, when a landscape is tilted, rivers respond in a distinct way such that river profiles take on unique forms that record tilt timing and magnitude. Using this suite of river forms, we estimated tilt timing and magnitude in the Sierra Nevada, USA, and results were consistent with independent measures. Our work broadens the scope of tectonic histories that can be extracted from landscape form to include tilting, which has been documented in diverse locations.
Georg Trost, Jörg Robl, Stefan Hergarten, and Franz Neubauer
Earth Surf. Dynam., 8, 69–85,Short summary
The evolution of the drainage system in the Eastern Alps is inherently linked to different tectonic stages. This leads to a situation in which major orogen-parallel alpine rivers, such as the Salzach and the Enns, are characterized by elongated east–west-oriented catchments. We investigate the stability of present-day drainage divides and the stability of reconstructed paleo-drainage systems. Our results indicate a progressive stability of the network towards the present-day situation.
Philippe Steer, Thomas Croissant, Edwin Baynes, and Dimitri Lague
Earth Surf. Dynam., 7, 681–706,Short summary
We use a statistical earthquake generator to investigate the influence of fault activity on river profile development and on the formation of co-seismic knickpoints. We find that the magnitude distribution of knickpoints resulting from a purely seismic fault is homogeneous. Shallow aseismic slip favours knickpoints generated by large-magnitude earthquakes nucleating at depth. Accounting for fault burial by alluvial cover can modulate the topographic expression of earthquakes and fault activity.
Guillaume Cordonnier, Benoît Bovy, and Jean Braun
Earth Surf. Dynam., 7, 549–562,Short summary
We propose a new algorithm to solve the problem of flow routing across local depressions in the topography, one of the main computational bottlenecks in landscape evolution models. Our solution is more efficient than the state-of-the-art algorithms, with an optimal linear asymptotic complexity. The algorithm has been designed specifically to be used within landscape evolution models, and also suits more generally the efficient treatment of large digital elevation models.
Meng Zhao, Gerard Salter, Vaughan R. Voller, and Shuwang Li
Earth Surf. Dynam., 7, 505–513,Short summary
Typically, we think of a shoreline growing with a smooth line separating the land and the water. If the growth is unstable, however, the land–water front will exhibit a roughness that grows with time. Here we ask whether the growth of deltaic shorelines cab be unstable. Through mathematical analysis we show that growth is unstable when the shoreline is building onto an adverse slope. The length scale of the unstable signal in such a case, however, might be obscured by other geomorphic processes.
Kristyna Falatkova, Miroslav Šobr, Anton Neureiter, Wolfgang Schöner, Bohumír Janský, Hermann Häusler, Zbyněk Engel, and Vojtěch Beneš
Earth Surf. Dynam., 7, 301–320,Short summary
In the last 50 years the Adygine glacier has been subject to relatively fast recession comparable to other glaciers in Tien Shan. As a consequence, a three-level cascade of glacial lakes formed, two of which were categorised as having medium outburst susceptibility. By 2050, the glacier is expected to have shrunk to 56–73 % of its 2012 extent. Further development of the site will result in formation of new lakes and probably also increase of outburst susceptibility due to permafrost degradation.
Andrin Caviezel, Sophia E. Demmel, Adrian Ringenbach, Yves Bühler, Guang Lu, Marc Christen, Claire E. Dinneen, Lucie A. Eberhard, Daniel von Rickenbach, and Perry Bartelt
Earth Surf. Dynam., 7, 199–210,Short summary
In rockfall hazard assessment, knowledge about the precise flight path of assumed boulders is vital for its accuracy. We present the full reconstruction of artificially induced rockfall events. The extracted information such as exact velocities, jump heights and lengths provide detailed insights into how rotating rocks interact with the ground. The information serves as future calibration of rockfall modelling tools with the goal of even more realistic modelling predictions.
John J. Armitage
Earth Surf. Dynam., 7, 67–75,Short summary
Landscape evolution models (LEMs) aim to capture an aggregation of the processes of erosion and deposition and predict evolving topography. A key aspect of any LEM is how water is chosen to be routed down the surface, which can impact the model results and, importantly, the numerical accuracy. I find that by treating flow as lines within the model domain and by distributing water down all slopes, the results are independent of resolution, pointing to a new method to model landscape evolution.
Ivar R. Lokhorst, Lisanne Braat, Jasper R. F. W. Leuven, Anne W. Baar, Mijke van Oorschot, Sanja Selaković, and Maarten G. Kleinhans
Earth Surf. Dynam., 6, 883–901,Short summary
In estuaries, mud sedimentation enhances salt marsh accretion. Here we explore system-scale effects of plants and mud on planform shape and size of estuaries. We coupled Delft3D for hydromorphodynamics with our vegetation model and ran controls for comparison. Effects are greatest at the fluvial–tidal transition, where for the first time in a model, a bedload convergence zone formed. Regardless of local vegetation effects, mud and vegetation cause gradual filling of estuaries over time.
Nikos Theodoratos, Hansjörg Seybold, and James W. Kirchner
Earth Surf. Dynam., 6, 779–808,Short summary
We perform dimensional analysis on a frequently used landscape evolution model (LEM). Defining characteristic scales in a novel way, we significantly simplify the LEM and develop an efficient numerical modeling approach. Our characteristic scales are physically meaningful; they quantify competitions between landscape-forming processes and are related to salient properties of landscape topography. Dimensional analyses of other LEMs may benefit from our approach in defining characteristic scales.
Gregory E. Tucker, Scott W. McCoy, and Daniel E. J. Hobley
Earth Surf. Dynam., 6, 563–582,Short summary
This article presents a new technique for computer simulation of slope forms. The method provides a way to study how events that disturb soil or turn rock into soil add up over time to produce landforms. The model represents a cross section of a hypothetical landform as a lattice of cells, each of which may represent air, soil, or rock. Despite its simplicity, the model does a good job of simulating a range of common of natural slope forms.
Liviu Giosan, Thet Naing, Myo Min Tun, Peter D. Clift, Florin Filip, Stefan Constantinescu, Nitesh Khonde, Jerzy Blusztajn, Jan-Pieter Buylaert, Thomas Stevens, and Swe Thwin
Earth Surf. Dynam., 6, 451–466,Short summary
Here we provide the first results on the evolution of the Ayeyarwady delta, the last unstudied megadelta of Asia. In addition to its intrinsic value as a founding study on the Holocene development of this region, we advance new ideas on the climate control of monsoonal deltas as well as describe for the first time a feedback mechanism between tectonics and tidal hydrodynamics that can explain the peculiarities of the Ayeyarwady delta.
John J. Armitage, Alexander C. Whittaker, Mustapha Zakari, and Benjamin Campforts
Earth Surf. Dynam., 6, 77–99,Short summary
We explore how two landscape evolution models respond to a change in climate. The two models are developed from a divergent assumption on the efficiency of sediment transport. Despite the different resulting mathematics, both numerical models display a similar functional response to a change in precipitation. However, if we model sediment transport rather than assume it is instantaneously removed, the model responds more rapidly, with a response time similar to that observed in nature.
Abigail L. Langston and Gregory E. Tucker
Earth Surf. Dynam., 6, 1–27,Short summary
While vertical incision in bedrock rivers is widely implemented in landscape evolution models, lateral erosion is largely ignored. This makes current models unfit to explain the formation of wide bedrock valleys and strath terraces. In this study we present a fundamental advance in the representation of lateral erosion of bedrock rivers in a landscape evolution model. The model results show a scaling relationship between valley width and drainage area similar to that found in natural systems.
Jeffrey S. Kwang and Gary Parker
Earth Surf. Dynam., 5, 807–820,Short summary
A prevalent bedrock incision relation used in landscape evolution is the stream power incision model (SPIM), which relates incision rate to drainage area to the m power and slope to the n power. We show the most commonly used ratio, m ∕ n = 0.5, leads to scale invariance: a landscape that has a horizontal domain of 1 km × 1 km has exactly the same relief pattern as one with a 100 km × 100 km domain. This conclusion indicates that SPIM must yield unrealistic results over a wide range of conditions.
Marc P. Hijma, Zhixiong Shen, Torbjörn E. Törnqvist, and Barbara Mauz
Earth Surf. Dynam., 5, 689–710,Short summary
We show that in the last 3 kyr the evolution of the Chenier Plain, >200 km west of the Mississippi Delta, was influenced by changes in the position of the main river mouth, local sediment sources and sea-level rise. This information can be used to constrain future generations of numerical models to obtain more robust predictions of the effects of improved sediment management and accelerated rates of relative sea-level rise on the evolution of mud-dominated coastal environments worldwide.
Vasiliki Mouslopoulou, John Begg, Alexander Fülling, Daniel Moraetis, Panagiotis Partsinevelos, and Onno Oncken
Earth Surf. Dynam., 5, 511–527,Short summary
A double coastal alluvial fan system on Crete is used as a proxy for landscape evolution. Each juxtaposed fan records individual phases of alluvial and marine incision, providing unprecedented resolution in the formation and evolution of its landscape. The fan sequence developed during MIS 3 due to sea-level fluctuations but it was preserved due to tectonic uplift during the subsequent 20 000 years. Thus, eustasy and tectonics were important in fan evolution, but over distinct time intervals.
Maarten Lupker, Jérôme Lavé, Christian France-Lanord, Marcus Christl, Didier Bourlès, Julien Carcaillet, Colin Maden, Rainer Wieler, Mustafizur Rahman, Devojit Bezbaruah, and Liu Xiaohan
Earth Surf. Dynam., 5, 429–449,Short summary
We use geochemical approaches (10Be) on river sediments to quantify the erosion rates across the Tsangpo-Brahmaputra (TB) catchment in the eastern Himalayas. Our approach confirms the high erosion rates in the eastern Himalayan syntaxis region and we suggest that the abrasion of landslide material in the syntaxis is a key process in explaining how erosion signals are transferred to the sediment load.
Robert R. Wells, Henrique G. Momm, and Carlos Castillo
Earth Surf. Dynam., 5, 347–367,Short summary
As technology presents a gateway to finer-resolution survey information, caution must be exercised in the evaluation of alignment error and subsequent morphological determinations. Three survey technologies were evaluated: ground-based photogrammetry, unmanned aerial vehicle photogrammetry, and ground-based lidar. Initial project planning necessitates the effective use of ground control to facilitate alignment and proper morphological conclusions.
Joris T. Eggenhuisen, Matthieu J. B. Cartigny, and Jan de Leeuw
Earth Surf. Dynam., 5, 269–281,Short summary
Suspension of particles in turbulent flows is one of the most widely occurring physical phenomena in nature, yet no theory predicts the sediment transport capacity of the wind, avalanches, pyroclastic flows, rivers, and estuarine or marine currents. We derive such a theory from universal turbulence characteristics and fluid and particle properties alone. It compares favourably with measurements and previous empiric formulations, making it the first process-based theory for particle suspension.
Margaux Mouchené, Peter van der Beek, Sébastien Carretier, and Frédéric Mouthereau
Earth Surf. Dynam., 5, 125–143,Short summary
The Lannemezan megafan (northern Pyrenean foreland) was abandoned during the Quaternary and subsequently incised. We use numerical models to explore possible scenarios for the evolution of this megafan. We show that autogenic processes are sufficient to explain its evolution. Climate may have played a second-order role; in contrast base-level change, tectonic activity and flexural isostatic rebound do not appear to have influenced its evolution.
Benjamin Campforts, Wolfgang Schwanghart, and Gerard Govers
Earth Surf. Dynam., 5, 47–66,Short summary
Despite a growing interest in landscape evolution models, accuracy assessment of the numerical methods they are based on has received little attention. We test a higher-order flux-limiting finite-volume method to simulate river incision and tectonic displacement. We show that this scheme significantly influences the evolution of simulated landscapes and the spatial and temporal variability of erosion rates. Moreover, it allows for the simulation of lateral tectonic displacement on a fixed grid.
Tom J. Coulthard and Christopher J. Skinner
Earth Surf. Dynam., 4, 757–771,Short summary
Landscape evolution models are driven by climate or precipitation data. We show that higher-resolution data lead to greater basin sediment yields (> 100 % increase) despite minimal changes in hydrological outputs. Spatially, simulations over 1000 years show finer-resolution data lead to a systematic bias of more erosion in headwater streams with more deposition in valley floors. This could have important implications for the long-term predictions of past and present landscape evolution models.
Joel P. L. Johnson
Earth Surf. Dynam., 4, 685–703,Short summary
Accurately predicting gravel transport rates in mountain rivers is difficult because of feedbacks with channel morphology. River bed surfaces evolve during floods, influencing transport rates. I propose that the threshold of gravel motion is a state variable for channel reach evolution. I develop a new model to predict how transport thresholds evolve as a function of transport rate, and then use laboratory flume experiments to calibrate and validate the model.
Jon D. Pelletier, Mary H. Nichols, and Mark A. Nearing
Earth Surf. Dynam., 4, 471–488,Short summary
This paper documents that a shift from grassland to shrubland within the past few thousand years has caused erosion rates to increase more than 10-fold and drainage density to increase approximately 3-fold in areas of otherwise similar climate and geology at a study site in Arizona. We provide a mathematical model that predicts the observed drainage density under both grassland and shrubland conditions. In the model application we are able to tightly constrain every parameter.
Guilhem Aubert, Vincent J. Langlois, and Pascal Allemand
Earth Surf. Dynam., 4, 327–342,Short summary
We performed the first direct numerical simulations of the process by which the pebbles transported by a river repeatedly impact its bedrock and consequently contribute to its erosion. Our results are consistent with existing experimental measurements and allow us to predict the incision rate of a river as a function of its water discharge, the amount of sediment available, and the roughness of the bedrock, which is essential to study the long-term evolution of mountain ranges.
Sébastien Carretier, Pierre Martinod, Martin Reich, and Yves Godderis
Earth Surf. Dynam., 4, 237–251,Short summary
We introduce moving clasts (grains, minerals, cobbles) in a landscape evolution model. This coupling has many potential applications, such as sediment provenance or the tracing of weathered material. It fills a gap between long-term landscape dynamics, which are difficult to tackle, and sediment clast populations studied in the field.
C. F. Brædstrup, D. L. Egholm, S. V. Ugelvig, and V. K. Pedersen
Earth Surf. Dynam., 4, 159–174,Short summary
When studying long-term glacial landscape evolution one must make simplifying assumptions about the nature of glacial flow. In this study we show that for two different numerical models such simplifications are mostly unimportant in the setting of glacial landscape evolution. Following this we find that glacial erosion is most intense in the early stages of glaciation and its effects are reduced with time due to flow patterns in the ice removing areas of highest resistance to flow.
J.-L. Grimaud, C. Paola, and V. Voller
Earth Surf. Dynam., 4, 11–23,Short summary
Knickpoints represent localized steps along a river profile (e.g. waterfalls or rapids) that are commonly interpreted as the geomorphic response of river systems to external changes. We used a simple experiment to show that knickpoints may not only respond to external base-level change but are also able to self-organize. We highlight the effect of alluvial cover in delaying knickpoint formation and show that river bed strength controls both retreat velocity and geometry of knickpoints.
J. L. Andersen, D. L. Egholm, M. F. Knudsen, J. D. Jansen, and S. B. Nielsen
Earth Surf. Dynam., 3, 447–462,Short summary
An increasing number of studies demonstrates links between the intensity of periglacial processes and bedrock erosion in steep mountain landscapes. Here, we quantify the dependence of periglacial processes on temperature and sediment thickness. This allows us to model frost processes across the full range of settings encountered in mountain landscapes. We find that sediment mantle thickness strongly modulates the relation between climate and periglacial weathering and sediment transport.
D. L. Egholm, J. L. Andersen, M. F. Knudsen, J. D. Jansen, and S. B. Nielsen
Earth Surf. Dynam., 3, 463–482,Short summary
We incorporate relations between climate, sediment thickness and periglacial processes quantified in the accompanying paper into a landscape evolution model. This allows us to time-integrate the periglacial contribution to mountain topography on million-year time scales. It is a robust result of our simulations that periglacial processes lead to topographic smoothing. Owing to the climate dependency, this smoothing leads to formation of low-relief surfaces at altitudes controlled by temperature.
A. R. Beer and J. M. Turowski
Earth Surf. Dynam., 3, 291–309,Short summary
We applied a spatiotemporally highly resolved dataset of discharge, sediment transport and bedrock erosion data to assess the validity of landscape evolution models at the process scale (resolution of square meters and minutes). The tools effect is found to be the dominant driver of erosion and an easy model is able to predict measured erosion. For larger scales common discharge-dependend modeling with a discharge threshold is adequate to regive the overal trend of the erosion signal.
R. M. Headley and T. A. Ehlers
Earth Surf. Dynam., 3, 153–170,Short summary
Within a landscape evolution model operating over geologic timescales, this work evaluates how different assumptions and levels of complexity for modeling glacier flow impact the pattern and amount of glacial erosion. Compared to those in colder climates, modeled glaciers in warmer and wetter climates are more sensitive to the choice of glacier flow model. Differences between landscapes evolved with different glacier flow models are intensified over multiple cycles.
L. Zhang, G. Parker, C. P. Stark, T. Inoue, E. Viparelli, X. Fu, and N. Izumi
Earth Surf. Dynam., 3, 113–138,Short summary
The saltation-abrasion model captures bedrock incision due stones striking bedrock. We present the Macro-Roughness-based Saltation-Abrasion-Alluviation (MRSAA) model, which tracks spatiotemporal variation of both bedload and alluvial thickness. It captures migrating waves of incision upstream and alluviation downstream. We apply it to incision problems not captured by saltation-abrasion, including the response to alluviation and stripping, and a simplified graben with uplift and subsidence.
M. Liang, V. R. Voller, and C. Paola
Earth Surf. Dynam., 3, 67–86,Short summary
In this work we present DeltaRCM, a reduced-complexity model for river delta formation. It is a rule-based cellular morphodynamic model, in contrast to reductionist models based on detailed computational fluid dynamics. DeltaRCM is able to resolve channel dynamics and to produce stratigraphy. We also explain the meaning of complexity reduction, especially the essential processes to be included in modeling deltas.
M. Liang, N. Geleynse, D. A. Edmonds, and P. Passalacqua
Earth Surf. Dynam., 3, 87–104,Short summary
In this work we assess the flow-routing component (FlowRCM) of our delta formation model, DeltaRCM. We found that with the level of complexity reduction, FlowRCM is able to produce channel network-scale hydrodynamic details, which provide further insights into the connection between delta flow structures and the morphodynamic outcome.
Earth Surf. Dynam., 2, 493–511,
A. Pelosi and G. Parker
Earth Surf. Dynam., 2, 243–253,
M. Scherler, S. Schneider, M. Hoelzle, and C. Hauck
Earth Surf. Dynam., 2, 141–154,
Z. Zhou, L. Stefanon, M. Olabarrieta, A. D'Alpaos, L. Carniello, and G. Coco
Earth Surf. Dynam., 2, 105–116,
M. Nones, M. Guerrero, and P. Ronco
Earth Surf. Dynam., 2, 9–19,
Abotalib, A. Z., Sultan, M., and Elkadiri, R.: Groundwater processes in Saharan Africa: Implications for landscape evolution in arid environments, Earth-Sci. Rev., 156, 108–136, 2016.
Abrams, D. M., Lobkovsky, A. E., Petroff, A. P., Straub, K. M., McElroy, B., Mohrig, D., Kudrolli, A., and Rothman, D. H.: Growth laws for channel networks incised by groundwater flow, Nat. Geosci., 2, 193–196, 2009.
Aqualinc Research Limited: Canterbury groundwater model 2. Christchurch (NZ), Aqualinc Research Limited, L07079/1, 2007.
Bal, A. A.: Valley fills and coastal cliff s buried beneath an alluvial plain: Evidence from variation of permeabilities in gravel aquifers, Canterbury Plains, New Zealand, J. Hydrol., 35, 1–27, 1996.
Berger, G. W., Tonkin, P. J., and Pillans, B.: Thermo-luminescence ages of post-glacial loess, Rakaia River, South Island, New Zealand, Quaternary Int., 35/36, 177–182, 1996.
Berhanu, M., Petroff, A. P., Devauchelle, O., Kudrolli, A., and Rothman, D. H.: Shape and dynamics of seepage erosion in a horiztonal granular bed, Phys. Rev. E, 86, 041304, https://doi.org/10.1103/PhysRevE.86.041304, 2012.
Browne, G. H. and Naish, T. R.: Facies development and sequence architecture of a late Quaternary fluvial-marine transition, Canterbury Plains and shelf, New Zealand: implications for forced regressive deposits, Sediment. Geol., 158, 57–86, 2003.
Buylaert, J.-P., Murray, A. S., and Thomsen, K. J.: Testing the potential of an elevated temperature IRSL signal from K-feldspar, Radio Measurements, 44, 560–565, 2009.
Buylaert, J. P., Thiel, C., Murray, A. S., Vandenberghe, D., Yi, S., and Lu, H.: IRSL and post-IR IRSL residual doses recorded in modern dust samples from the Chinese Loess Plateau, Geochronometria, 38, 432–440, 2011.
Chu-Agor, M. L., Fox, G. A., Cancienne, R. M., and Wilson, G. V.: Seepage caused tension failures and erosion undercutting of hillslopes, J. Hydrol., 359, 247–259, 2008.
Coelho Netto, A. L., Fernandes, N. F., and Edegard de Deus, C.: Gullying in the southeastern Brazilian Plateau, Bananal, SP, in: Proceedings of the Porto Alegre Symposium, Porto Alegre, Brazil, 11–15 December 1988, 35–42, 1988.
Collins, B. D. and Sitar, N.: Geotechnical properties of weakly and moderately cemented sands in steep slopes, J. Geotech. Geoenviron., 135, 1359–1366, 2009.
Collins, B. D. and Sitar, N.: Stability of steep slopes in cemented sands, J. Geotech. Geoenviron., 137, 43–51, 2011.
Constable, S. C., Parker, R. L., and Constable, C. G.: Occam's inversion: Apractical algorithm for generating smooth models from EM sounding data, Geophysics, 52, 289–300, 1987.
Dann, R., Close, M., Flinto, M., Hector, R., Barlow, H., Thomas, S., and Francis, G.: Characterization and estimation of hydraulic properties in an alluvial gravel vadose zone, Vadose Zone J., 8, 651–663, 2009.
Davey, G.: Definition of the Canterbury Plains Aquifers, Environment Canterbury, UK, U06/10, 2006.
Domenico, P. A. and Schwartz, F. W.: Physical and Chemical Hydrogeology, John Wiley, Chichester, UK, 528 pp., 1997.
DroneDeploy: DroneDeploy, available at: https://www.dronedeploy.com/, last access: 30 November 2017.
Dunne, T.: Hydrology, mechanics, and geomorphic implications of erosion by subsurface flow, in: Groundwater Geomorphology: The Role of Subsurface Water in Earth-Surface Processes and Landforms, edited by: Higgins, C. G. and Coates, D. R., Geological Society of America, Boulder, CO, USA, 1–25, 1990.
Environment Canterbury: River flow data, available at: https://www.ecan.govt.nz/data/riverflow, last access: 2 April 2019.
Fitterman, D. V.: Tools and techniques: Active-source electromagnetic methods, in: Resources in the Near-Surface Earth, Treatise on Geophysics, edited by: Slater, L., Elsevier, Amsterdam, the Netherlands, 295–333, 2015.
Fox, G. A., Wilson, G. V., Periketi, R. K., and Cullum, R. F.: Sediment transport model for seepage erosion of streambank erosion, J. Hydrol. Eng., 11, 603–611, 2006.
Fredlund, D. G. and Krahn, J.: Comparison of slope stability methods of analysis, Can. Geotech. J., 14, 429–439, 1977.
Fredlund, D. G., Krahn, J., and Pufahl, D.: The relationship between limit equilibrium slope stability methods, in: Proceedings of the 10th International Conference on Soil Mechanics and Foundation Engineering, Stockholm, Sweden, 15–19 June 1981, 409–416, 1981.
Geonics: G-TEM Operating Manual, Geonics Ltd., Mississauga, Canada, 2016.
Gibb, J. G.: Rates of coastal erosion and accretion in New Zealand, New Zeal. J. Mar. Fresh., 12, 429–456, 1978.
Harrison, K. P. and Grimm, R. E.: Groundwater-controlled valley networks and the decline of surface runoff on early Mars, J. Geophys. Res., 110, E12S16, https://doi.org/10.1029/2005JE002455, 2005.
Higgins, C. G.: Drainage systems developed by sapping on Earth and Mars, Geology, 10, 147–152, 1982.
Higgins, C. G. (Ed.): Piping and sapping: Development of landforms by groundwater flow, Allen and Unwin, St. Leonards, 18–58, 1984.
Howard, A. D.: Groundwater sapping on Earth and Mars, in: Sapping Features of the Colorado Plateau, edited by: Howard, A. D., Kochel, R. C., and Holt, H. R., NASA Washington D.C., USA, 1–4, 1988.
Howard, A. D.: Case study: Model studies of ground-water sapping, in: Geological Society of America Special Paper, edited by: Higgins, C. G. and Coates, D. R., Geological Society of America, Boulder, CO, USA, 257–264, 1990.
Howard, A. D.: Simulation modeling and statistical classification of escarpment planforms, Geomorphology, 12, 187–214, 1995.
Howard, A. D. and McLane, C. F.: Erosion of cohesionless sediment by groundwater seepage, Water Resour. Res., 24, 1659–1674, 1988.
Interpex: IXG-TEM Instruction Manual, Interpex Ltd., Golden, CO, USA, 2012.
Interpex: IXG-TEM, available at: http://interpex.com/, last access: 31 July 2020.
Kirk, R. M.: River-beach interaction on mixed sand and gravel coasts: A geomorphic model for water resource planning, Appl. Geogr., 11, 267–287, 1991.
Kline, S. W., Adams, P. N., and Limber, P. W.: The unsteady nature of sea cliff retreat due to mechanical abrasion, failure and comminution feedbacks, Geomorphology, 219, 53–67, 2014.
Kochel, R. C. and Piper, J. F.: Morphology of large valleys on Hawaii – Evidence for groundwater sapping and comparisons with Martian valleys, J. Geophys. Res., 91, 175–192, 1986.
Kochel, R. C., Howard, A. D., and McLane, C. F.: Channel networks developed by groundwater sapping in fine-grained sediments: Analogs to some Martian valleys, in: Models in Geomorphology, edited by: Woldenberg, M., Allen and Unwin, St. Leonards, Australia, 313–341, 1985.
Laity, J. E. and Malin, M. C.: Sapping processes and the development of theater-headed valley networks in the Colorado Plateau, Geol. Soc. Am. Bull., 96, 203–217, 1985.
Lamb, M. P., Howard, A. D., Johnson, J., Whipple, K. X., Dietrich, W. E., and Perron, J. T.: Can springs cut canyons into rock?, J. Geophys. Res., 111, E07002, https://doi.org/10.1029/2005JE002663, 2006.
Lapotre, M. G. A. and Lamb, M. P.: Substrate control on valley formation by groundwater on Earth and Mars, Geology, 46, 531–534, 2018.
Laporte-Fauret, Q., Marieu, V., Castelle, B., Michalet, R., Bujan, S., and Rosebery, D.: Low-Cost UAV for High-Resolution and Large-Scale Coastal Dune Change Monitoring Using Photogrammetry, J. Mar. Sci. Eng., 7, 63, https://doi.org/10.3390/jmse7030063, 2019.
Leckie, D. A.: Modern environments of the Canterbury Plains and adjacent offshore areas, New Zealand – an analog for ancient conglomeratic depositional systems in nonmarine and coastal zone settings, B. Can. Petrol. Geol., 51, 389–425, 2003.
Leyland, J. and Darby, S. E.: An empirical-conceptual gully evolution model for channelled sea cliffs, Geomorphology, 102, 419–434, 2008.
Leyland, J. and Darby, S. E.: Effects of Holocene climate and sea-level changes on coastal gully evolution: insights from numerical modelling, Earth Surf. Proc. Land., 34, 1878–1893, 2009.
Limber, P. W. and Barnard, P. L.: Coastal knickpoints and the competition between fluvial and wave-driven erosion on rocky coastlines, Geomorphology, 306, 1–12, 2018.
Lobkovsky, A. E., Jensen, B., Kudrolli, A., and Rothman, D. H.: Threshold phenomena in erosion driven by subsurface flow, J. Geophys. Res., 109, F04010, https://doi.org/10.1029/2004JF000172, 2004.
Mackey, B. H., Scheingross, J. S., Lamb, M. P., and Farley, K. A.: Knickpoint formation, rapid propagation, and landscape response following coastal cliff retreat at the last interglacial sea-level highstand: Kaua'i, Hawai'i, Geol. Soc. Am. Bull., 126, 925–942, 2014.
Malin, M. C. and Carr, M. H.: Groundwater formation of Martian valleys, Nature, 397, 589–591, 1999.
Micallef, A., Person, M., Haroon, A., Weymer, B. A., Jegen, M., Schwalenberg, K., Faghih, Z., Duan, S., Cohen, D., Mountjoy, J. J., Woelz, S., Gable, C. W., Averes, T., and Tiwari, A. K.: 3D characterisation and quantification of an offshore freshened groundwater system in the Canterbury Bight, Nat. Commun., 11, 1372, https://doi.org/10.1038/s41467-020-14770-7, 2020.
Moreton, D. J., Ashworth, P. J., and Best, J. L.: The physical scale modelling of braided alluvial architecture and estimation of subsurface permeability, Basin Res., 14, 265–285, 2002.
Nabighian, M. N. and Macnae, J. C.: 6. Time Domain Electromagnetic Prospecting Methods, in: Electromagnetic Methods in Applied Geophysics: Volume 2, Application, Parts A and B, edited by: Nabighian, M. N., Society of Exploration Geophysicists, Houston, USA, 427–520, 1991.
Nash, D. J.: Groundwater sapping and valley development in the Hackness Hills, North Yorkshire, England, Earth Surf. Proc. Land., 21, 781–795, 1996.
Nash, D. J., Shaw, P. A., and Thomas, D. S. G.: Duricrust development and valley evolution: Process-landforms links in the Kalahari, Earth Surf. Proc. Land., 19, 299–317, 1994.
Newell, M.: Canyonlands – modern history, Naturalist, 21, 40–47, 1970.
Onda, Y.: Seepage erosion and its implications to the formation of amphitheatre valley heads: A case study at Obara, Japan, Earth Surf. Proc. Land., 19, 624–640, 1994.
Pelletier, J. D. and Baker, V. R.: The role of weathering in the formation of bedrock valleys on Earth and Mars: A numerical modeling investigation, J. Geophys. Res., 116, E11007, https://doi.org/10.1029/2011JE003821, 2011.
Petroff, A. P., Devauchelle, O., Abrams, D. M., Lobkovsky, A. E., Kudrolli, A., and Rothman, D. H.: Geometry of valley growth, J. Fluid Mech., 673, 245–254, 2011.
Pillans, B.: Drainage initiation by subsurface flow in South Taranaki, New Zealand, Geology, 13, 262–265, 1985.
Pondthai, P., Everett, M. E., Micallef, A., Weymer, B. A., Faghih, Z., Haroon, A., and Jegen, M.: 3D characterization of a coastal freshwater aquifer in SE Malta (Mediterranean Sea) by time-domain electromagnetics, Water, 12, 1566, https://doi.org/10.1029/2011JE003821, 2020.
Preusser, F., Chithambo, M. L., Götte, T., Martini, M., Ramseyer, K., Sendezera, E. J., Susino, G. J., and Wintle, A. G.: Quartz as a natural luminescence dosimeter, Earth-Sci. Rev., 97, 184–214, 2009.
Rocscience: Slide2, available at: https://www.rocscience.com/software/slide2, last access: 31 July 2020.
Schorghofer, N., Jensen, B., Kudrolli, A., and Rothman, D. H.: Spontaneous channelization in permeable ground: Theory, experiment, and observation, J. Fluid Mech., 503, 357–374, 2004.
Schumm, S. A. and Phillips, L.: Composite channels of the Canterbury Plain, New Zealand: A Martian analog?, Geology, 14, 326–329, 1986.
Schumm, S. A., Boyd, K. F., Wolff, C. G., and Spitz, W. J.: A groundwater sapping landscape in the Florida panhandle, Geomorphology, 12, 281–297, 1995.
Scott, G. L.: Near-surface hydraulic stratigraphy of the Canterbury Plains between Ashburton and Rakaia rivers, New Zealand, J. Hydrol., 19, 68–74, 1980.
Skempton, A. W.: The pore-pressure coefficents A and B, Geotechnique, 4, 143–147, 1954.
Sunderlin, D., Trop, J. M., Idleman, D., Brannick, A., White, J. G., and Grande, L.: Paleoenvironment and paleoecology of a Late Paleocene high-latitude terrestrial succession, Arkose Ridge Formation at Box Canyon, southern Talkeetna Mountains, Alaska, Palaeogeogr. Palaeocl., 401, 57–80, 2014.
Thiel, C., Buylaert, J.-P., Murray, A., Terhorst, B., Hofer, I., Tsukamoto, S., and Frechen, M.: Luminescence dating of the Stratzig loess profile (Austria) – Testing the potential of an elevated temperature post-IR IRSL protocol, Quaternary Int., 234, 23–31, 2011.
Uchupi, E. and Oldale, R. N.: Spring sapping origin of the enigmatic relict valleys of Cape Cod and Martha's Vineyard and Nantucket Islands, Massachussets, Geomorphology, 9, 83–95, 1994.
Weymer, B. A., Wernette, P. A., Everett, M. E., Pondthai, P., Jegen, M., and Micallef, A.: Multi-layered high permeability conduits connecting onshore and offshore coastal aquifers, Frontiers in Marine Science, 7, 903, https://doi.org/10.3389/fmars.2020.531293, 2020.
Whitaker, S.: Flow in Porous-Media I: a theoretical derivation of Darcy's-Law, Transport Porous Med., 1, 3–25, 1986.
Wilson, G. V., Periketi, R., Fox, G. A., Dabney, S., Shields, D., and Cullum, R. F.: Seepage erosion properties contributing to streambank failure, Earth Surf. Proc. Land., 32, 447–459, 2007.
Ye, F.-Y., Barriot, J.-P., and Carretier, S.: Initiation and recession of the fluvial knickpoints of the Island of Tahiti (French Polynesia), Geomorphology, 186, 162–173, 2013.
Yi, R., Cohen, Y., Devauchelle, O., Gibbins, G., Seybold, H. F., and Rothman, D. H.: Symmetric rearrangement of groundwater-fed streams, Philos. T. Roy. Soc. A, 473, 20170539, https://doi.org/10.1098/rspa.2017.0539, 2017.
We study coastal gullies along the Canterbury coast of New Zealand using field observations, sample analyses, drones, satellites, geophysical instruments and modelling. We show that these coastal gullies form when rainfall intensity is higher than 40 mm per day. The coastal gullies are formed by landslides where buried channels or sand lenses are located. This information allows us to predict where coastal gullies may form in the future.
We study coastal gullies along the Canterbury coast of New Zealand using field observations,...