The Aculeo Lake is an important natural reservoir of Central Chile, which provides valuable ecosystem services. This lake has suffered a rapid shrinkage of the water levels from year 2010 to 2018, and since October 2018, it is completely dry. This natural disaster is concurrent with a number of severe and uninterrupted drought years, along with sustained increases in water consumption associated to land use/land cover (LULC) changes. Severe water shortages and socio-environmental impacts were triggered by these changes, emphasizing the need to understand the causes of the lake desiccation to contribute in the design of future adaptation strategies. Thereby, the Water Evaluation and Planning (WEAP) hydrological model was used as a tool to quantify the water balance in the catchment. The model was run under a combination of three land use/land cover and two different climate scenarios that sample the cases with and without megadrought and with or without changes in land use. According to the results, the main triggering factor of the lake shrinkage is the severe megadrought, with annual rainfall deficits of about 38%, which resulted in amplified reductions in river flows (44%) and aquifer recharges (24%). The results indicate that the relative impact of the climate factor is more than 10 times larger than the impact of the observed LULC changes in the lake balance, highlighting the urgent need for adaptation strategies to deal with the projected drier futures.

阿库里奥湖是智利中部重要的天然水库，可提供宝贵的生态系统服务。从2010年到2018年，该湖的水位迅速萎缩，自2018年10月以来，它已经完全干燥。这种自然灾害与许多严重和不间断的干旱年份并存，同时伴随着土地利用/土地覆被变化（LULC）的用水量持续增加。这些变化引发了严重的水短缺和社会环境影响，强调需要了解湖泊干燥的原因，以为未来的适应策略的设计做出贡献。因此，用水评估和计划（WEAP）水文模型被用作量化流域水量平衡的工具。该模型是在三个土地利用/土地覆盖以及两个不同的气候情景的组合下运行的，该情景对有或没有特大干旱以及有或没有土地利用变化的情况进行了抽样。根据结果​​，湖泊萎缩的主要诱因是严重的特大干旱，年降雨量不足约38％，这导致河流流量的减少（44％）和含水层补给的增加（24％）。结果表明，气候因子的相对影响比所观察到的LULC变化对湖泊平衡的影响大10倍以上，这突出表明迫切需要采取适应策略来应对较早的干旱。导致湖泊萎缩的主要诱因是严重的特大干旱，年降雨量不足约38％，这导致河流流量（44％）和蓄水层补给（24％）的增加减少。结果表明，气候因子的相对影响比所观察到的LULC变化对湖泊平衡的影响大10倍以上，这突出表明迫切需要采取适应策略来应对较早的干旱。导致湖泊萎缩的主要诱因是严重的特大干旱，年降雨量不足约38％，这导致河流流量（44％）和蓄水层补给（24％）的增加减少。结果表明，气候因子的相对影响比所观察到的LULC变化对湖泊平衡的影响大10倍以上，这突出表明迫切需要采取适应策略来应对较早的干旱。