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| Titel |
Geomorphic change detection in small Alpine basins using LiDAR DTMs |
| VerfasserIn |
Beatrice Goldin, Marco Cavalli, Francesco Comiti, Lorenzo Marchi |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250076516
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| Zusammenfassung |
| Morphological change evaluation of earth surface is an important task in environmental
monitoring. Methods devoted to the assessment of geomorphic changes can be used to
identify geomorphologically unstable areas, to quantify processes intensity and to compute
sediment budgets. Digital elevation models (DEMs) built from repeated topographic
surveys can be used to produce DEM of Difference (DoD) maps and to estimate
volumetric changes through time. Nowadays LiDAR technology provides digital models
representative of the bare earth surface (Digital Terrain Models – DTMs) at high
spatial resolution and over large spatial extents, thus contributing to the increase
of accuracy of morphometric and volumetric measurement of varying surfaces.
In this study, high-resolution DTMs derived from airborne LiDAR data acquired in different
years (2006 and 2011) were used in order to characterize sediment transport processes such
as debris flows and bedload transport in two small Alpine basins. Two DTMs (2 m resolution)
were derived for the Gadria and Strimm catchments (Vinschgau-Venosta valley, Autonomous
Province of Bozen-Bolzano, Italy). These basins, which cover, respectively, areas of 6.3 and
8.5 km2, have been chosen due to their contrasting morphology and because they
feature different types and intensity of sediment transfer processes: Gadria channel is
characterized by frequent occurrence of debris flows (almost one debris flow per year),
whereas Strimm is essentially a bedload stream. A method based on fuzzy logic
(Wheaton et al., 2010), which takes into account DTM uncertainties, was used to derive
the DoD of the study area. The comparison between the 2006 and 2011 DTMs
permitted the assessment of morphometric changes at the basin scale over the 5
yrs period. The results of DoD analysis are consistent with field observations of
erosion and sediment transport. Besides, the DoD proved useful to identify the
relationship between erosion, deposition or no-change areas and geomorphometric
parameters (e.g. slope, curvature, upslope area) relevant for topographic evolution of the
landscape.
References: Wheaton J.M., Brasington J., Darby S. E., Shear D. A., 2010. Accounting for
uncertainty in DTMs from repeat topographic surveys: improved sediment budges. Earth
Surface Processes and Landforms, 35, 136-156. |
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