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| Titel |
Reading the bed morphology of a mountain stream: a geomorphometric study on high-resolution topographic data |
| VerfasserIn |
S. Trevisani, M. Cavalli, L. Marchi |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 14, no. 2 ; Nr. 14, no. 2 (2010-02-26), S.393-405 |
| Datensatznummer |
250012192
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| Publikation (Nr.) |
 copernicus.org/hess-14-393-2010.pdf |
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| Zusammenfassung |
| High-resolution topographic data expand the potential of quantitative
analysis of the earth surface, improving the interpretation of geomorphic
processes. In particular, the morphologies of the channel beds of mountain
streams, which are characterised by strong spatial variability, can be
analysed much more effectively with this type of data. In this study, we
analysed the aerial LiDAR topographic data of a headwater stream, the Rio
Cordon (watershed area: 5 km2), located in the Dolomites (north-eastern
Italy). The morphology of the channel bed of Rio Cordon is characterised by
alternating step pools, cascades, and rapids with steps. We analysed the
streambed morphology by means of ad hoc developed morphometric indices, capable of
highlighting morphological features at a high level of spatial resolution.
To perform the analysis and the data interpolation, we carried out a
channel-oriented coordinate transformation. In the new coordinate system,
the calculation of morphometric indices in directions along and transverse
to the flow direction is straightforward. Three geomorphometric indices were
developed and applied as follows: a slope index computed on the whole width
of the channel bed, directional variograms computed along the flow direction
and perpendicular to it, and local anomalies, calculated as the difference
between directional variograms at different spatial scales. Directional
variograms in the flow direction and local anomalies have proven to be
effective at recognising morphologic units, such as steps, pools and
clusters of large boulders. At the spatial scale of channel reaches, these
indices have demonstrated a satisfactory capability to outline patterns
associated with boulder cascades and rapids with steps, whereas they did not
clearly differentiate between morphologies with less marked morphological
differences, such as step pools and cascades. |
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