Geomorphic coupling and sediment connectivity in an alpine catchment — Exploring sediment cascades using graph theory

Heckmann, Tobias; Schwanghart, Wolfgang

doi:10.1016/j.geomorph.2012.10.033

Cited by 217 publications

(193 citation statements)

References 72 publications

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“…Such a multiscale framework was conceptualized by Heckmann and Schwanghart (2013), who clearly distinguished the coupling of processes and connectivity. On the one hand, geomorphic coupling is "the linkage of distinct landforms or landscape units by sediment transport" (Harvey, 2001); it refers to "elementary interactions at the relatively small scale" (Faulkner, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…On the one hand, geomorphic coupling is "the linkage of distinct landforms or landscape units by sediment transport" (Harvey, 2001); it refers to "elementary interactions at the relatively small scale" (Faulkner, 2008). On the other hand, "the degree of coupling, the combined effect of lateral (hillslope to channel) and longitudinal (from one river reach to another) linkages between system components, is termed (sediment) connectivity" (Heckmann and Schwanghart, 2013). Shifting from the local to the catchment scale remains the main issue in explaining how erosion and sediment transfer at small spatial scale interact and result in broad-scale geomorphic patterns and processes (Bracken et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…One promising field of research has been opened up by the application of graph theory, which offers mathematical tools to analyze statistically the assemblages of all the components of a sediment cascade. It is a spatially explicit analysis since nodes and edges are spatial objects and since distance plays a role in the modeling (Heckmann and Schwanghart, 2013;Heckmann et al, 2015). This mathematical approach is based on a graph representation of the hydrological network that has been used for decades to describe watercourses shape and organization (Strahler, 1957;Chorley and Kennedy, 1971;Shreve, 1974).…”

Section: Introductionmentioning

confidence: 99%

“…The challenge is thus to open the black boxes that remain within a sediment cascade, which requires both accurate geomorphic investigations in the field (reconstruction of sequences of geomorphic evolution, description of sediment pathways) and the development of tools dedicated to sediment cascade modeling. More precisely, the development of tools devoted to the study of connectivity in geomorphology is still in progress, although graph theory offers promising perspectives (Heckmann and Schwanghart, 2013). In this paper, graph theory is applied to abstract the network structure of sediment cascades, keeping only the nodes (sediment sources, sediment stores, outlet) and links (linkage by a transportation agent), represented as vertices and edges.…”

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confidence: 99%

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Assessment of structural sediment connectivity within catchments: insights from graph theory

Cossart

Fressard

2017

Earth Surf. Dynam.

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Abstract.To describe the sedimentary signal delivered at catchment outlets, many authors now refer to the concept of connectivity. In this framework, the sedimentary signal is seen as an emergent organization of local links and interactions. The challenge is thus to open the black boxes that remain within a sediment cascade, which requires both accurate geomorphic investigations in the field (reconstruction of sequences of geomorphic evolution, description of sediment pathways) and the development of tools dedicated to sediment cascade modeling. More precisely, the development of tools devoted to the study of connectivity in geomorphology is still in progress, although graph theory offers promising perspectives (Heckmann and Schwanghart, 2013). In this paper, graph theory is applied to abstract the network structure of sediment cascades, keeping only the nodes (sediment sources, sediment stores, outlet) and links (linkage by a transportation agent), represented as vertices and edges. From the description of the assemblages of sedimentary flows, we provide three main indices to explore how small-scale processes may result in significant broad-scale geomorphic patterns. The main hypothesis guiding this work is that the network structure dictates how sediment inputs from various sources interact at tributary junctions and finally at the outlet of a cascading system. First, we use the flow index to assess the potential contribution of each node to the sediment delivery at the outlet. Second, we measure the influence of each node regarding how it is accessible from both sediment sources and the outlet (using the Shimbel index). Third, we propose a new connectivity index named "Network Structural Connectivity index" (NSC) revealing whether the potential contribution of a node is lower or higher than expected from its location within the network. These indices are first computed for a conceptual sediment cascade network and then applied to a catchment located in the southern French Alps. We demonstrate that this index may be used to simulate sediment transfer and help in identifying the hotspots of geomorphic change. In the present case, we try to predict how a sediment cascade may be impacted by an edge disruption or a reconnection.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Assessment of structural sediment connectivity within catchments: insights from graph theory

Cossart

Fressard

2017

Earth Surf. Dynam.

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“…The concept of connectivity has increasingly been used in quantitative process-based sediment dynamics research, especially at catchment scales (Ali et al, 2014;Baartman et al, 2013;Bracken and Croke, 2007;Bracken et al, 2015;Brierley et al, 2006;Cavalli et al, 2013;Fryirs et al, 2007;Heckmann and Schwanghart, 2013;Lexartza-Artza and Wainwright, 2011;López-Vicente et al, 2013;Wainwright et al, 2011). Geomorphology has been considered as a major driver on determining sediment connectivity (Heckmann and Schwanghart, 2013;Theler et al, 2010), and geomorphometric indices have increasingly been developed to assess it (Borselli et al, 2008;Cavalli et al, 2013;López-Vicente et al, 2013;Reid et al, 2007;Sougnez et al, 2011).…”

Section: Sediment Connectivitymentioning

confidence: 99%

Rainfall simulation and Structure-from-Motion photogrammetry for the analysis of soil water erosion in Mediterranean vineyards

Prosdocimi

Burguet

Prima

et al. 2017

Science of The Total Environment

102

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Soil water erosion is a serious problem, especially in agricultural lands. Among these, vineyards deserve attention, because they constitute for the Mediterranean areas a type of land use affected by high soil losses. A significant problem related to the study of soil water erosion in these areas consists in the lack of a standardized procedure of collecting data and reporting results, mainly due to a variability among the measurement methods applied. Given this issue and the seriousness of soil water erosion in Mediterranean vineyards, this works aims to quantify the soil losses caused by simulated rainstorms, and compare them with each other depending on two different methodologies: (i) rainfall simulation and (ii) surface elevation change-based, relying on high-resolution Digital Elevation Models (DEMs) derived from a photogrammetric technique (Structure-from-Motion or SfM). The experiments were carried out in a typical Mediterranean vineyard, located in eastern Spain, at very fine scales. SfM data were obtained from one reflex camera and a smartphone built-in camera. An index of sediment connectivity was also applied to evaluate the potential effect of connectivity within the plots. DEMs derived from the smartphone and the reflex camera were comparable with each other in terms of accuracy and capability of estimating soil loss. Furthermore, soil loss estimated with the surface elevation change-based method resulted to be Contents lists available at ScienceDirectScience of the Total Environment j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / s c i t o t e n v of the same order of magnitude of that one obtained with rainfall simulation, as long as the sediment connectivity within the plot was considered. High-resolution topography derived from SfM revealed to be essential in the sediment connectivity analysis and, therefore, in the estimation of eroded materials, when comparing them to those derived from the rainfall simulation methodology. The fact that smartphones built-in cameras could produce as much satisfying results as those derived from reflex cameras is a high value added for using SfM.

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Investigating decadal‐scale geomorphic dynamics in an alpine mountain setting

2015

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We know little about the effect of recent climate variability upon landscapes at the timescale of decades because of (1) the complex, nonlinear, and path‐dependent nature of the response of a landscape to climate forcing and (2) the difficulty of quantifying spatially distributed impacts at the timescale of decades to centuries, despite this being the timescale over which significant hypotheses have been raised over human impacts upon climate change and hence geomorphic systems. A unique resource to investigate the linkages between climatic variability and geomorphic response is provided by the extensive coverage of aerial imagery commonly available since the 1950s. Here we use archival digital photogrammetry to produce high‐precision digital elevation models over large spatial scales, and so to reconstruct the quantitative history of surface downwasting and sediment flux in a high mountain alpine system, over the timescales of decades. Propagation of error methods is used to identify locations of significant landscape response and to compute volumes of significant surface change. Orthorectified aerial images are used in an image correlation framework to detect horizontal and vertical displacements of components of the landscape. Results are coupled to extant climate data and modeled snow cover to show how the landscape responds to climate forcing and to geomorphological maps to understand how this response varies between landscape elements. The results show distinct landscape response to both warming and cooling periods and a tendency for the acceleration of surface displacement under warming conditions. Precipitation and snow cover are critical in controlling glacier dynamics and rock glacier displacement velocities. However, while some landforms might lead to locally high sediment flux, landscape heritage can disconnect zones of high change rates from the valley bottom. Hence, the landscape response to climate forcing is not necessarily reflected in valley system processes or sediment deposits.

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Geomorphic coupling and sediment connectivity in an alpine catchment — Exploring sediment cascades using graph theory

Cited by 217 publications

References 72 publications

Assessment of structural sediment connectivity within catchments: insights from graph theory

Assessment of structural sediment connectivity within catchments: insights from graph theory

Rainfall simulation and Structure-from-Motion photogrammetry for the analysis of soil water erosion in Mediterranean vineyards

Investigating decadal‐scale geomorphic dynamics in an alpine mountain setting

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