Increasing water demand due to population growth, economic expansion and the need for development puts a strain on the supply capacity of the Vaal River catchment in South Africa. Climate change presents additional challenges in the catchment which supports the country's economic hub, more than 30% of its population and over 70% of its maize production. This study evaluates the influence of climate change on current and future intra-annual water availability and demand using a multi-tiered approach where climate scenarios, hydrological modelling and socio-economic considerations were applied. Results shows exacerbated water supply challenges for the future. Temperature increases of between 0.07 and 5 °C and precipitation reductions ranging from 0.4 to 30% for Representative Concentration Pathways (RCPs) 4.5 and 8.5, respectively, are also predicted by the end of the century. The highest monthly average streamflow reductions (8–10%) are predicted for the summer months beyond 2040. Water Evaluation and Planning (WEAP) simulations project an increase in future water requirements, gaps in future water assurance and highlight limitations in existing management strategies. The study recommends a combination of adaptation plans, climatic/non-climatic stressor monitoring, wastewater-reuse, conservation, demand management and inter-basin transfers to reduce future uncertainty in monthly water sustainability.

由于人口增长，经济扩张和发展需求，水资源需求不断增加，这给南非瓦尔河流域的供应能力带来了压力。气候变化给流域带来了更多挑战，流域为该国的经济中心，人口的30％以上和玉米产量的70％以上提供了支持。这项研究使用一种多层次的方法来评估气候变化对当前和未来年度年内水供应和需求的影响，其中采用了气候情景，水文模型和社会经济因素。结果表明，未来的供水挑战更加严峻。代表浓度途径（RCP）分别为4.5和8.5时，温度升高了0.07至5°C，降水量减少了0.4％至30％，到本世纪末也有预测。预计到2040年以后的夏季，每月平均流量减少量最高（8-10％）。用水评估和规划（WEAP）模拟预测未来的用水需求将增加，未来的用水保证将出现缺口，并突出说明现有管理策略的局限性。该研究建议将适应计划，气候/非气候压力源监控，废水回用，保护，需求管理和流域间转移相结合，以减少未来每月水资源可持续性的不确定性。未来水质保障方面的差距，突出现有管理策略的局限性。该研究建议将适应计划，气候/非气候压力源监控，废水回用，保护，需求管理和流域间转移相结合，以减少未来每月水资源可持续性的不确定性。未来水质保障方面的差距，突出现有管理策略的局限性。该研究建议将适应计划，气候/非气候压力源监控，废水回用，保护，需求管理和流域间转移相结合，以减少未来每月水资源可持续性的不确定性。