This research investigated the impact of climate change on the Eerste River, which is the primary source of water for the Stellenbosch Municipality and the agricultural sector in the surrounding areas of Stellenbosch Town, South Africa. Climate data projected by 11 Global Circulation Models (GCMs) of the Coupled Model Intercomparison Project - Phase 5 enforced by Representative Concentration Pathways 4.5 and 8.5, was statistically downscaled to reflect the “near” (2022–2057) and “far” (2058–2093) future periods, respectively. The ensemble mean of these GCMs outputs for the near and far future periods was compared to that of the present-day period which was accepted as the period between 1983 and 2018. This was done to determine the climate change signal, which was then transferred onto the observed precipitation and evaporation data of the present-day period. The climate change induced data, as well as land use and water demand analysed data, were then used as input to the Pitman Model, which is the conceptual semi-distributed hydrological model, for the simulation of the impact of climate change on the flow of the Eerste River. The results showed that climate change is expected to increase evaporation between 6% and 15% and, at the same time, causing rainfall to decrease between 2% and 8% in the future periods. This future climate is anticipated to cause a reduction in available water of between 8% and 18%, potentially triggering an increase in irrigation demand of between 12% and 29% in the future periods with a possible failure to meet the municipal water abstractions expected in the far-future period. Therefore, this research suggests increasing the capacity of existing farm dams and the promotion of water demand management practices to curb the potential impact of climate change on the available flow of the Eerste River.

这项研究调查了气候变化对埃斯特河的影响，埃斯特河是南非斯泰伦博斯市和南非斯泰伦博斯镇周边地区农业部门的主要水源。由代表性浓度途径4.5和8.5实施的耦合模型比对项目的第11阶段全球环流模型（GCM）预测的气候数据在第5阶段进行了统计缩减，以反映“近”（2022-2057）和“远”（2058- 2093年）。将这些GCM的近期和远期产出的总体平均值与被认为是1983年至2018年的当今时期的总体平均值进行了比较。这样做是为了确定气候变化信号，然后将其转移到今天观察到的降水和蒸发数据上。然后，将气候变化引起的数据以及土地利用和需水分析数据用作Pitman模型的输入，Pitman模型是概念性的半分布式水文模型，用于模拟气候变化对河流流量的影响。埃斯特河。结果表明，气候变化预计将使蒸发增加6％至15％，同时，在未来一段时间内，降雨将减少2％至8％。预计未来的气候将导致可用水减少8％至18％，未来可能会导致灌溉需求增加12％至29％，并且有可能无法满足未来一段时期的市政取水要求。因此，这项研究表明，增加现有农田水坝的能力，并促进水资源需求管理措施，以遏制气候变化对埃斯特河可用流量的潜在影响。