Farai Dondofema
University of Venda, South Africa.
Title: Determining the relationship between gully characteristics and environmental factors at sub catchment level using GIS and remote sensing in Zimbabwe
Biography
Biography: Farai Dondofema
Abstract
GIS and remote sensing techniques were used to identify and monitor gully erosion, and its relationship with selected environmental factors in Zhulube in Zimbabwe. The results showed that gully characteristics are significantly explained by soil characteristics, environmental factors, slope gradient, sediment loadings and the erosive power of streams. There was an evident, significant (p<0.05) relationship between gully depth and bulk density at r2=0.873. The soil clay content was another soil property that showed a significant relationship with gully development with its related minerals, indicating a decline in erosion with an increase in proportions. A significant relationship between gully depths and slope gradient showed a resultant increase of r2= 0.62. There was a significant relationship between gully development and the erosive power of stream while sediment loadings of the streams indicated a non-significant effect on the gully depth with an r2=0.02. The susceptibility of soils to detachment and transport by various erosive agents was a function of soil properties including, among others, physical and chemical soil properties. The effects of each soil property were different between sites, thereby influencing the degree of vulnerability of any given soil to destructive erosion forces. The interactive effects of the topography, vegetation cover and rainfall factors greatly influenced erosive agents. Soil erodibility assessment using simulated stream erosive forces and sediment loadings revealed that sediment yield or the erosive power of the streams in the study area increased with increasing slope gradient depending on the clay content of the soil.