Siem Reap River plays a crucial role in maintaining the stability of the Angkor Temple Complex and the livelihoods of the people in the basin. Land use and land cover (LULC) have changed considerably over the last few decades, as well as climatic regime, and these, in turn, have an influence on streamflow. The objective of this study was to assess the potential impacts of future LULC and climate change on streamflow upstream from the Angkor Temple Complex. LULC maps, classification of LULC units, and projections of change were developed using Maximum Likelihood Supervised Classification and the Land Change Modeler (LCM). Artificial neural network (ANN) downscaling was applied to downscale precipitation and temperatures. The Soil and Water Assessment Tool (SWAT) was applied to assess the effects of future LULC and climate change within the upper Siem Reap catchment. The Mann-Kendall test was employed to detect any potential trends within the current and future (modelled) streamflow. The results indicate that there would be reduction of streamflow at seasonal and annual timescales, under every scenario. The annual average streamflow was reduced −69%, −63% and −75% under the Representative Concentration Pathway (RCP) scenarios RCP 2.6, RCP 4.5 and RCP 8.5 respectively. It seems that there is a sufficient water supply to sustain the Angkor Temple Complex under the current LULC and climate regime, but there would be an insufficient water supply under every future modelled scenario. Moreover, trends in groundwater levels must be taken into account, because growing population will inevitably influence groundwater balance and surface water which could potentially threaten the stability of Angkor Wat Temple, a UNESCO World Heritage Site.

暹粒河对维持吴哥寺庙群的稳定和流域人民的生计起着至关重要的作用。在过去的几十年中，土地利用和土地覆盖 (LULC) 以及气候状况发生了很大变化，而这些反过来又对河流流量产生了影响。本研究的目的是评估未来 LULC 和气候变化对吴哥寺庙群上游水流的潜在影响。LULC 地图、LULC 单位分类和变化预测是使用最大似然监督分类和土地变化建模器 (LCM) 开发的。人工神经网络 (ANN) 降尺度应用于降尺度降水和温度。土壤和水评估工具 (SWAT) 用于评估暹粒上游流域内未来 LULC 和气候变化的影响。Mann-Kendall 检验用于检测当前和未来（模拟的）水流中的任何潜在趋势。结果表明，在每种情况下，季节性和年度时间尺度上的流量都会减少。在代表性浓度路径 (RCP) 情景 RCP 2.6、RCP 4.5 和 RCP 8.5 下，年平均流量分别减少了 -69%、-63% 和 -75%。在当前的 LULC 和气候状况下，似乎有足够的供水来维持吴哥寺庙群，但在每个未来的模拟情景下，供水都将不足。此外，必须考虑地下水位的趋势，