This study used the Soil and Water Assessment Tool (SWAT) model together with regional climate downscaled (RCD) data from the CORDEX (Africa project), to assess the local seasonal precipitation variability in the upper middle catchment (UMC) of the Olifants River basin. The study results, based on two scenarios (RCP4.5 and RCP8.5), showed a wider monthly and seasonal variability of precipitation. The study also indicated a strong decreasing trend of east-to-west direction of spatial precipitation, with most precipitation concentrated in the eastern part of the study area. Within the western part of the UMC, we also noted another decreasing trend of precipitation from south-to-north with northern areas of the study area receiving the least amount of precipitation. This study has also revealed a considerable general reduction of future seasonal precipitation especially in the mid-term period (2021–2050). The general reduction in future seasonal precipitation, combined with the increasing temperatures in the area, may exacerbate the drought conditions and reduction in streamflow of the main river (Olifants) and its tributaries, consequently having a negative impact on the economic activities in the basin.

这项研究使用土壤和水评估工具（SWAT）模型以及来自CORDEX（非洲项目）的区域气候缩减（RCD）数据，来评估Olifants流域上中流域（UMC）的当地季节性降水变化。基于两种情况（RCP4.5和RCP8.5）的研究结果表明，降水的月度和季节变化更大。研究还表明，空间降水的东西方方向呈强烈下降趋势，大部分降水集中在研究区域的东部。在UMC的西部，我们还注意到降水量从南到北呈下降趋势，研究区域的北部地区降水量最少。这项研究还揭示了未来季节降水的总体下降，特别是在中期（2021-2050年）。未来季节性降水的普遍减少，再加上该地区气温的升高，可能会加剧干旱条件，以及主要河流（奥利夫特人）及其支流的流量减少，因此对该流域的经济活动产生负面影响。