An investigation of the Spatial Distribution of Soil Erosion in the Mbuluzi River Basin of Swaziland

Abstract

Soil erosion is widespread in Swaziland and is very severe on small holder farms and communal grazing areas. The Middleveld of Swaziland is the most affected. Erosion occurs on deep colluvial and saprolitic materials and is associated with convexslope breaks. The erosion upstream of drainage basins affects economic activities downstream especially irrigated agriculture because it contributes sediment yield hence reducing the lifespan of dams and reservoirs. Water and soil pollution is also involved. The paper investigates the spatical distribution of soil eriosion in the Mbuluzi river basin through a visual interpretation of satellite imagery. The results indicate that soil erosion is widespread in the basin. Over 55% of the basin is affected by moderate erosion where estate farming and controlled grazing are the main land uses. Very severe erosion takes place over almost 12% of the area where communal grazing and small holder farms are predominant. It is recommended that a National Land Use policy be established whereby the management of the drainage basins is integrated to include all stakeholders. In this way the environmental impact of all development activities can be reviewed and ameliorative measures agreed upon.

UNISWA Research Journal of Agriculture, Science and Technology Vol 3 (2) 2000: pp 32-37