A segmentation approach for the reproducible extraction and quantification of knickpoints from river long profiles

  • Changes in the steepness of river profiles or abrupt vertical steps (i.e. waterfalls) are thought to be indicative of changes in erosion rates, lithology or other factors that affect landscape evolution. These changes are referred to as knickpoints or knickzones and are pervasive in bedrock river systems. Such features are thought to reveal information about landscape evolution and patterns of erosion, and therefore their locations are often reported in the geomorphic literature. It is imperative that studies reporting knickpoints and knickzones use a reproducible method of quantifying their locations, as their number and spatial distribution play an important role in interpreting tectonically active landscapes. In this contribution we introduce a reproducible knickpoint and knickzone extraction algorithm that uses river profiles transformed by integrating drainage area along channel length (the so-called integral or chi method). The profile is then statistically segmented and the differing slopes and step changes in the elevations ofChanges in the steepness of river profiles or abrupt vertical steps (i.e. waterfalls) are thought to be indicative of changes in erosion rates, lithology or other factors that affect landscape evolution. These changes are referred to as knickpoints or knickzones and are pervasive in bedrock river systems. Such features are thought to reveal information about landscape evolution and patterns of erosion, and therefore their locations are often reported in the geomorphic literature. It is imperative that studies reporting knickpoints and knickzones use a reproducible method of quantifying their locations, as their number and spatial distribution play an important role in interpreting tectonically active landscapes. In this contribution we introduce a reproducible knickpoint and knickzone extraction algorithm that uses river profiles transformed by integrating drainage area along channel length (the so-called integral or chi method). The profile is then statistically segmented and the differing slopes and step changes in the elevations of these segments are used to identify knickpoints, knickzones and their relative magnitudes. The output locations of identified knickpoints and knickzones compare favourably with human mapping: we test the method on Santa Cruz Island, CA, using previously reported knickzones and also test the method against a new dataset from the Quadrilatero Ferrifero in Brazil. The algorithm allows for the extraction of varying knickpoint morphologies, including stepped, positive slope-break (concave upward) and negative slope-break knickpoints. We identify parameters that most affect the resulting knickpoint and knickzone locations and provide guidance for both usage and outputs of the method to produce reproducible knickpoint datasets.show moreshow less

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Metadaten
Author details:Boris GailletonORCiD, Simon M. MuddORCiDGND, Fiona J. ClubbORCiD, Daniel PeiferORCiD, Martin D. HurstORCiD
DOI:https://doi.org/10.5194/esurf-7-211-2019
ISSN:2196-6311
ISSN:2196-632X
Title of parent work (English):Earth surface dynamics
Publisher:Copernicus
Place of publishing:Göttingen
Publication type:Article
Language:English
Date of first publication:2019/02/18
Completion year:2019
Release date:2021/04/07
Volume:7
Issue:1
Page number:20
First page:211
Last Page:230
Funding institution:European UnionEuropean Union (EU) [674899 - SUBITOP]; NERCNERC Natural Environment Research Council [NE/J009970/1]; Geo.X fellowship; Coordination for the Improvement of Higher Education Personnel (CAPES) under a Science without Borders fellowship [BEX 12000/13-2]; German Aerospace Center (DLR)Helmholtz AssociationGerman Aerospace Centre (DLR) [DEM_GEOL1345]
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Geowissenschaften
DDC classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
Peer review:Referiert
Publishing method:Open Access / Gold Open-Access
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License (German):License LogoCreative Commons - Namensnennung, 4.0 International