Determination of stream flow reduction associated with afforestation on a selected quaternary catchment of the Crocodile River, Mpumalanga

M.Sc.The foresty industry is a very important industry m South Africa. Forestry is mostly practised in rural areas. Commercial plantations cover only 1.18% of the area of South Africa, with Mpumalanga Province having the largest area and greatest density of commercial plantations. This is because Mpumalanga province is physiographically and climatically conducive to afforestation. The study area, quaternary catchment X22D, is situated in Mpumalanga province; about 80 percent of this catchment is afforested with pine. The hydrological impact of afforestation in the study area is estimated in this study using two models, namely Shell and Affdem3. The impact of afforestation on surface flow depends on the percentage of the afforested area in a catchment, the rotational period, the genera, and the availability of water. As the percentage of afforested area in a catchment increases, so does the consumption of water by the trees increase. This author found that there is a positive relationship between the consumption of water by trees, and the rotational period and the availability of water. Also: Eucalyptus and Pine are consuming more water than Wattle. Understanding these effects of afforestation on water resources at the level of a quaternary catchment is a fundamental requirement in optimal water resource allocation and the long-term sustainable use of water. Keywords: Afforestation, stremflow, hydrological models, riparian zone, afforestation permit system