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Titel |
Accurate drainage network extraction and monitoring in a high-mountain catchment |
VerfasserIn |
Raphael Mutzner, Paolo Tarolli, Marc B. Parlange, Andrea Rinaldo |
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 |
250080108
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Zusammenfassung |
We study the accuracy of channel network extraction methods obtained in two subcatchments
of an alpine watershed in Switzerland and compare the results to the ones obtained with the
real network, carefully monitored with a high precision DGPS during Summer 2011. A 1 x 1
m2 LiDAR-derived Digital Terrain Model is used for the automatic channel extraction
method. We compare automatic and objective geomorphic feature extraction to the more
classic methods based on thresholding of drainage area and local slope. The analysis of the
drainage density underlined that the results are consistent for channel network derived by
proper morphometric approaches compared to the results obtained with the monitored
network, while drainage density derived under standard methodologies proved to be
unreliable. Our results suggests a careful combination of field validation and automatic
morphometric approaches, while they cast serious doubts on classic approaches based on
standard topographic thresholds in complex high-mountain environments where
heterogeneity of initiation processes is the norm. Moreover, 281 channel heads are
analyzed in the Slope-Area (S-A) diagram and classified along two different initiation
processes, namely groundwater seeping upward and runoff induced channels. The
first ones tend to imply lower topographic thresholds of A and S with respect to
those initiated by runoff processes, whereas linear regressions indicate a rather poor
inverse relationship between A and S for both mechanisms of channel initiation. |
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