Intersecting views of gully erosion in South Africa

G. Olivier, M. J. Van De Wiel, W. P. de Clercq

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8 Citations (Scopus)
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Abstract

Gully erosion is an environmental problem recognized as one of the worst land degradation processes worldwide. Insight into regional gully perturbations is required to combat the serious on- and off-site impacts of gullying on a catchment management scale. In response, we intersect different perspectives on gully erosion-specific views in South Africa (SA), a country that exhibits various physiographic properties and spans 1.22 million km2. While the debate surrounding gully origin continues, there is consensus that anthropogenic activities are a major contemporary driver. The anthropogenic impact caused gullying to transcend climatic, geomorphic, and land-use boundaries, although it becomes more prominent in central to eastern SA. Soil erodibility plays a crucial role in what extent of gully erosion severity is attained from human impact, contributing to the east–west imbalance of erosion in SA. Soil erosion rates from gullying and badlands are limited but suggest that it ranges between 30 and 123 t ha−1 yr−1 in the more prominent areas. These soil loss rates are comparable to global rates where gullying is concerned; moreover, they are up to four orders of magnitude higher than the estimated baseline erosion rate. On a national scale, the complexity of gullying is evident from the different temporal timings of (re)activation or stabilizing and different evolution rates. Continued efforts are required to understand the intricate interplay of human activities, climate, and preconditions determining soil erodibility. In SA, more medium- to long-term studies are required to understand better how changing control factors affect gully evolution. More research is needed to implement and appraise mitigation measures, especially using indigenous knowledge. Establishing (semi)-automated mapping procedures would aid in gully monitoring and assessing the effectiveness of implemented mitigation measures. More urgently, the expected changes in climate and land-use necessitate further research on how environmental change affects short-term gully erosion dynamics.
Original languageEnglish
Pages (from-to)119-142
Number of pages24
JournalEarth Surface Processes and Landforms
Volume48
Issue number1
Early online date8 Dec 2022
DOIs
Publication statusPublished - 9 Jan 2023

Bibliographical note

This is an open access article under the terms of theCreative Commons Attribution-NonCommercial-NoDerivsLicense, which permits use and distribution in anymedium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.© 2022 The Authors.Earth Surface Processes and Landformspublished by John Wiley & Sons Ltd

Funder

This research was supported through theCollaborative Research Grant from CoventryUniversity, awarded to Dr M.J. Van De Wieland Dr W.P. de Clercq. Further support wasreceived from the National ResearchFoundation of South Africa through theAUDA-NEPAD SANWATCE WARFSA AlignedResearch Grants Programme, awarded to MrG. Olivier and Dr W.P. de Clercq

Keywords

  • South Africa
  • contemporary driving and control factors
  • donga
  • gully erosion
  • gully origin
  • gully processes
  • remote sensing
  • review
  • soil loss

ASJC Scopus subject areas

  • Geography, Planning and Development
  • Earth-Surface Processes
  • Earth and Planetary Sciences (miscellaneous)

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