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Morphometric controls and geomorphic responses on fans in the Southern Alps, New Zealand
Author(s) -
de Scally Fes A.,
Owens Ian F.
Publication year - 2004
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.1022
Subject(s) - structural basin , debris , debris flow , geology , landslide , drainage basin , geomorphology , physical geography , hydrology (agriculture) , geography , cartography , oceanography , geotechnical engineering
Morphometric variables associated with 41 debris‐ow and 18 uvial fans and their basins in the Southern Alps of New Zealand are examined. The results show statistically signicant differences in the area, maximum elevation, relief and ruggedness (Melton's R ) of the basin and the area, gradient, and apex and toe elevations of the fan between debris‐ow and uvial sites. Concavity of the fan longitudinal prole also differs between the two fan types, although this could not be tested statistically. Most of these morphometric differences reect differences in processes and environmental controls on them. Discriminant analysis indicates that basin area and fan gradient best differentiate the two fan types by process. Moderately strong correlations exist, on both debris‐ow and uvial fans, between basin area or Melton's R and fan area. Correlations between basin area or Melton's R and fan gradient are generally weaker. The results of this study also indicate that on debris‐ow‐prone fans the fan gradient and basin Melton's R have lower thresholds which overlap little with upper thresholds associated with basins where only streamow reaches the fan. These thresholds may therefore have value in preliminary morphometric assessments of debris‐ow hazard on fans in the Southern Alps. Copyright © 2004 John Wiley & Sons, Ltd.