Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 14 8 2010 10.5194/hess-14-1697-2010 http://www.hydrol-earth-syst-sci.net/14/1697/2010/ http://www.hydrol-earth-syst-sci.net/14/1697/2010/hess-14-1697-2010.html http://www.hydrol-earth-syst-sci.net/14/1697/2010/hess-14-1697-2010.pdf 1697 1713 2010-08-31 A geophysical analysis of hydro-geomorphic controls within a headwater wetland in a granitic landscape, through ERI and IP E. S. Riddell edriddell@gmail.com S. A. Lorentz D. C. Kotze School of Bioresources Engineering and Environmental Hydrology, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa Centre for Environment and Development, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa Wetlands are undergoing considerable degradation in South Africa. As interventions are often technical and costly, there is a requirement to develop conceptual process models for these wetland systems so that rehabilitation attempts will be successful. This paper presents an approach using the geophysical methods of Electrical Resistivity Imaging (ERI) and Induced Polarization (IP) to delineate sub-surface hydro-geomorphic controls that maintain equilibrium disconnectivity of wetland-catchment processes, which through gully erosion are increasing the catchments connectivity through loss of water and sediment. The findings presented here give insight into the geomorphic processes that maintain the wetland in an un-degraded state, this allows for the development of a conceptual model outlining the wetland forming processes. The analysis suggests that sub-surface clay-plugs, within an otherwise sandy substrate are created by illuviation of clays from the surrounding hillslopes particularly at zones of valley confinement. Acocks, J. P. 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