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| Titel |
Landscape evolution of the northern Hsuehshan Range in Taiwan inferred from fluvial channel morphology |
| VerfasserIn |
Cheng-Hung Chen, J. Bruce H. Shyu |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250104950
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| Publikation (Nr.) |
 EGU/EGU2015-4393.pdf |
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| Zusammenfassung |
| The evolution of topography is fundamentally coupled with changes in river channel
networks. Erosion rate of a river system into a landscape depends on many factors, including
climate, base level, tectonics and lithology. Most previous studies assumed that river
networks and watershed boundaries are stable through time. However, if rivers on both sides
of the drainage divide have different erosion rates, the divide may move due to the erosion
rate difference. In this study, we used a new method of the fluvial geomorphic index Ï to
analyze the river networks in the northern Hsuehshan Range of Taiwan. The parameter Ï
provides a prediction of steady-state elevation for a given point along a channel. By
comparing the Ï values of river tributaries on both sides of the drainage divide, we
can obtain the information of the divide condition. If Ï values are similar on both
sides of the divide, the boundary is generally stable. By contrast, if Ï values are
very different on the two sides, the boundary is unstable, and the river systems
will migrate toward the high Ï side until they achieve a stable configuration. We
found that on the same side of the northern Hsuehshan Range main divide, the river
basins are generally stable, but the main water divide of the Hsuehshan Range is
unstable. Based on the results of Ï values, river steepness index (ksn), satellite image
analysis, and field investigations, the main drainage divide may move from southeast to
northwest at a rate of about 10 mm/yr. This movement is likely produced by the general
tectonic setting of the area and the activity of the Northern Ilan structure. From our
results, we also propose a mechanism for how rivers interact with each other on both
sides of the water divide. We hope this study would provide more information for
reconstructing river basins in the past and understanding their developments in the future. |
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