Accelerated erosion is a major environmental, social and economical threat in South Africa. It is estimated that in excess of 400 million tones of soil is lost every year in South Africa, with much of this erosion being attributed to improper land management and little or no erosion control methods. This study was aimed to determine the efficiency of soil erosion structures, which were constructed in the Mabula Private Game Reserve (Limpopo Province), in reducing the amount of sediment eroded at the sites as well as to determine the amounts of sediments deposited due to their presence. Factors such as rainfall, slope, soil type and particle size were measured to determine their influence on sediment erosion and the ultimate deposition of this sediment. The geology of the area is characterised by Waterberg Sandstones and igneous intrusions of mostly granite. Rainfall in the area occurs between the October and April, with an average of 550 – 750 mm. The temperatures range from 18°C - 32°C during the summer months and 4°C to 22°C in the winter months. The study area falls within the Sour Bushveld and the Sourish Mixed Bushveld, according to the Acocks classification. These veld types are characterised by open an open savanna of tall trees and shrubs. Five sites affected by soil erosion were selected and at each site structures were constructed, the size and number of structures at each site was dependant on the extent of the sites area. The structures are made from a shade net product known as T65, a shade cloth developed by Alnet, which has not been UV treated allowing it to disintegrate in the open atmosphere after 2-3 years. Soil measurements and samples were taken before the rainfall season to establish baseline data to compare the results with once the filed work has been concluded. Thereafter samples and measurements were taken every month during the rainfall season, which extended from October 2004 to April 2005. In conjunction with the measurements taken at each structure the slope of each site was determined and the profiles of the sediment deposited at the structures after the rainfall season were studied. From the measurements it was clear that as the rainfall increased so the amount of sediment being deposited at the structures increased. There were structures that experienced more iii sediment deposition than others and theses differences could be attributed to factors such as parent material, soil texture, slope angle and soil type. Due to the deposition of sediment and the reduction in surface flow caused by the structures, vegetation established itself and began to flourish in the newly deposited soil. Through the establishment of vegetation at the sites an element of success was achieved. With a total of 2 101 mm of sediment being deposited at the structures and the establishment of vegetation in areas where there was none previously it can be concluded that the soil erosion structures are successfully curbing soil erosion in Mabula Private Game Reserve. / Professor J.T. Harmse
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:2206 |
| Date | 23 May 2008 |
| Creators | Beringer, Grant |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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