Favis-Mortlock, D., Boardman, J., Foster, I. D. L. and Greenwood, P. (2018) ‘Local gradient’ and between-site variability of erosion rate on badlands in the Karoo, South Africa. Earth Surface Processes and Landforms. 43, pp. 871-883. 0197-9337.
| Item Type: | Article |
|---|---|
| Abstract: | Site-average values of local gradient, defined as the steepest slope angle measured at a point, are a powerful predictor of long-term rates of soil loss as measured by erosion pins on the non-channel floor portions of ten badland study sites in the Karoo area of South Africa. Local gradient may be easily measured using a smartphone clinometer. The successful use of local gradient here is in strong contrast to the previous failure of other site-specific attributes, including other measures of gradient and relief, to explain between-site variation in erosion rate on these study sites. Each measurement of local gradient may be thought of as a sample of the site’s microtopography. Microrelief is a strong determinant of the emergent patterns of inter-channel overland flow, and hence of the patterns of inter-channel erosion by flow. Local gradient changes most rapidly during the initial stages of channel incision. When channels are established, local gradient changes more slowly leading to almost-parallel retreat of channel sidewalls. A sensitivity analysis suggests that measurements of local gradient are not all equal with regard to prediction of long-term erosion rate. A greater share of predictive power is contributed by measurements made on very steep or vertical channel side wall areas, and a lesser share is contributed by measurements made on interfluves. |
| Uncontrolled Keywords: | Karoo, badlands, clinometer app, local gradient, microtopography, soil erosion |
| Creators: | Favis-Mortlock, David, Boardman, John, Foster, Ian D L and Greenwood, Philip |
| Faculties, Divisions and Institutes: | Faculties > Faculty of Arts, Science & Technology > Environmental Science |
| Date: | 30 March 2018 |
| Date Type: | Publication |
| Page Range: | pp. 871-883 |
| Journal or Publication Title: | Earth Surface Processes and Landforms |
| Volume: | 43 |
| Number of Pages: | 13 |
| Language: | English |
| DOI: | https://doi.org/10.1002/esp.4293 |
| ISSN: | 0197-9337 |
| Status: | Published / Disseminated |
| Refereed: | Yes |
| URI: | http://nectar.northampton.ac.uk/id/eprint/10693 |
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