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Gully erosion susceptibility modelling to support avoided degradation planning.

Gully erosion susceptibility modelling to support avoided degradation planning.

Authors :
le Roux, Jay
van der Waal, Bennie
Source :
South African Geographical Journal. Sep2020, Vol. 102 Issue 3, p406-420. 15p.
Publication Year :
2020

Abstract

Restoration resources are usually limited and strategic information on and erosion susceptible areas are required to avoid further degradation. This study has potential in the Mzimvubu River Catchment, South Africa, where two large reservoirs are planned on the Tsitsa tributary. The Tsitsa River Catchment, however, consists of highly erodible soils with widespread gully erosion evident. It is important to prevent further gully erosion in the catchment due to the presence of duplex and dispersive soils. Therefore, this study modelled areas that are susceptible to gully development in the Tsitsa River Catchment, as well as estimated the sediment yield potential from the susceptible areas if gully development occurs. This was achieved by mapping gully-free areas in a GIS that have the same DEM-derived topographical variables, soil associations and land cover as gullied areas, followed by scenario analysis of the potential sediment yield. More than 30 000 ha (7%) of the catchment is intrinsically susceptible to further gully development, consisting of drainage paths with a large contributing area and erodible duplex soils. If not protected, these susceptible areas could contribute an additional 300 million m3 of sediment to the river network, reducing the volumes of both reservoirs by more than 50%. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
03736245
Volume :
102
Issue :
3
Database :
Academic Search Index
Journal :
South African Geographical Journal
Publication Type :
Academic Journal
Accession number :
145051231
Full Text :
https://doi.org/10.1080/03736245.2020.1786444