A Historical Analysis of Rainfall Trend in the Olifants Basin in South Africa

A set of homogeneity test methods and the Mann-Kendall trend test were applied on historical rainfall records of the Olifants Basin to detect changes in rainfall pattern under a changing climate. In total, historical rainfall records from 13 stations obtained from the South African Weather Service (SAWS) and the Department of Water Affairs (DWA) spanning the period 1975-2013 were used in the analysis. Results of the study indicate an insignificant declining rainfall trend in the Olifants Basin with a mean annual rainfall of 664 mm. Rainfall in the basin exhibits spatio–temporal variation with coefficient of variation of 24%. Inter-annual and seasonal variability is dominant in the records examined. Changes observed in rainfall over the years were therefore concluded to have resulted due to climate change impacts.