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Titel |
Evaluating digital terrain indices for soil wetness mapping – a Swedish case study |
VerfasserIn |
A. M. Ågren, W. Lidberg, M. Strömgren, J. Ogilvie, P. A. Arp |
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 ; 18, no. 9 ; Nr. 18, no. 9 (2014-09-12), S.3623-3634 |
Datensatznummer |
250120470
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Publikation (Nr.) |
copernicus.org/hess-18-3623-2014.pdf |
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Zusammenfassung |
Trafficking wet soils within and near stream and lake buffers can cause soil
disturbances, i.e. rutting and compaction. This – in turn – can lead to
increased surface flow, thereby facilitating the leaking of unwanted
substances into downstream environments. Wet soils in mires, near streams and
lakes have particularly low bearing capacity and are therefore more
susceptible to rutting. It is therefore important to model and map the extent
of these areas and associated wetness variations. This can now be done with
adequate reliability using a high-resolution digital elevation model (DEM).
In this article, we report on several digital terrain indices to predict soil
wetness by wet-area locations. We varied the resolution of these indices to
test what scale produces the best possible wet-areas mapping conformance. We
found that topographic wetness index (TWI) and the newly
developed cartographic depth-to-water index (DTW) were the best
soil wetness predictors. While the TWI derivations were sensitive
to scale, the DTW derivations were not and were therefore
numerically robust. Since the DTW derivations vary by the area
threshold for setting stream flow initiation, we found that the optimal
threshold values for permanently wet areas varied by landform within the
Krycklan watershed, e.g. 1–2 ha for till-derived landforms versus 8–16 ha
for a coarse-textured alluvial floodplain. |
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