This study aims to evaluate the impacts of climate change on water balance components, mainly precipitation, water yield, and evapotranspiration and hydrological extremes in three physiographic regions namely the Middle Mountain region, the High Mountain region, and the High Himalayas region of the West Seti River Basin (WSRB) in Nepal. The future climate was projected using the climate data of three Regional Climate Models (RCMs). The projected future climate data was then fed into the hydrological model, Soil and Water Assessment Tool (SWAT), to simulate hydrologic responses including water balance components under future climate conditions. Results showed that the Middle Mountain region of the basin is expected to receive the highest increase of in precipitation (11.2%) and in water yield (18.2%) as compared to the other two physiographic regions. Conversely, the High Himalayas are expected to have the highest increase of evapotranspiration (19.9%) as compared to the Middle Mountain and High Mountain regions. Similarly, the low flows in the basin are expected to decrease by −15.5% and −19.3% under Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios, respectively. Whereas high flows are expected to increase by 10.7% under both the RCP scenarios. The results of this study will be helpful to planners and decision makers to formulate adaptation strategies in water resources development and planning such as irrigation and hydropower development.

这项研究旨在评估气候变化对西部塞提的中部山区，高山地区和喜马拉雅山高地区三个自然地理区域的水平衡要素的影响，主要是降水量，水产量，蒸散量和水文极端值。尼泊尔流域（WSRB）。使用三个区域气候模型（RCM）的气候数据预测了未来的气候。然后将预计的未来气候数据输入到水文模型土壤和水评估工具（SWAT）中，以模拟包括未来气候条件下的水平衡成分在内的水文响应。结果表明，该盆地的中部山区有望获得最大的降水量（11.2％）和水产量（18。2％）。相反，与中部山区和高山地区相比，预计喜马拉雅山的蒸散量增长最快（19.9％）。同样，在代表浓度路径（RCP）4.5和8.5情景下，流域的低流量预计分别减少-15.5％和-19.3％。在两种RCP方案下，高流量预计将增长10.7％。这项研究的结果将有助于规划者和决策者制定水资源开发和规划（如灌溉和水电开发）中的适应策略。在代表浓度路径（RCP）4.5和8.5情景下，流域的低流量预计将分别降低-15.5％和-19.3％。在两种RCP方案下，高流量预计将增长10.7％。这项研究的结果将有助于规划者和决策者制定水资源开发和规划（如灌溉和水电开发）中的适应策略。在代表浓度路径（RCP）4.5和8.5情景下，流域的低流量预计将分别降低-15.5％和-19.3％。在两种RCP方案下，高流量预计将增长10.7％。这项研究的结果将有助于规划者和决策者制定水资源开发和规划（如灌溉和水电开发）中的适应策略。