Publication: Morfología Fluvial.-Intrinsic properties of channel network structure and the hierarchical classification approach for stream-limits delineation
Authors
Afana, A. ; Del Barrio, G.
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Universidad de Murcia
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DOI
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info:eu-repo/semantics/other
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Abstract
ABSTRACT
Delineation of drainage networks is an essential task in hydrological and geomorphological
analysis. Manual channel definition depends on topographic contrast and is highly subjective,
leading to important errors at high resolutions. Different automatic methods have proposed
the use of a constant threshold of upslope contributing area to define channel initiation.
Actually, these are the most commonly used for the automatic-channel network extraction
from Digital Elevation Models (DEMs). However, these methods fail to detect an appropriate
threshold when the basin is made up of heterogeneous sub-zones, as they only work either
lumped or locally. In this study, the critical threshold area for channel delineation has been
defined through the analysis of dominant geometric and topologic properties of stream
network formations. In addition, a hierarchical classification approach has been integrated in
order to verify landscape units in relation to dominant intrinsic properties. Such approach
provides various critical thresholds as much as necessary in relation to DEM-data resolution
as well as homogeneity or heterogeneity of the dominant landforms. The study has been
carried out in two controlled drainage basins with different lithology and geomorphic
processes. High-resolution DEMs (1m) were used to obtain the best detailed drainage
network that the algorithm can generate in a homogeneous landscape, whereas a mediumresolution
DEM (30m) was applied in a heterogeneous complex landscape. Validation results
revealed that the above approach is adequate for describing terrain dissection, since its
function depends on intrinsic properties of the drainage network, being at the same time
objective and easy to implement. Likewise, it provides an enhanced approximation to
empirical geomorphometric parameters used to describe stream network dimensions.
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