Abstract Lake-aquifer interactions have been the subject of investigation and debate for decades. Traditional investigation methods include measurement of water flux across the groundwater–surface water interface, application of heat and environmental tracer methods, conducting numerical simulations of the water flow, and mass balance–based approaches. We first review, evaluate and describe the different approaches that have been applied for examining lake-aquifer interactions and propose an additional complementary approach. While the leakage from lakes and its slow movement through porous media (laminar flow) is well characterized by existing methods, modeling the rapid and turbulent flow through preferred pathways (faults/karst) remains a challenging task. To better understand the nature, and the full scale, of the lake-aquifer interactions, and using Lake Nasser and the underlying Dakhla subbasin of the Nubian Sandstone Aquifer System (NSAS) in the Western Desert of Egypt (area: 0.66 × 106 km2) as a test site, we examine, model, and correlate temporally and spatially, the variations in Gravity Recovery and Climate Experiment terrestrial water storage (GRACETWS) solutions, with precipitation, lake levels, area, and water volume. We review current GRACE applications in hydrology and present our novel approach. Findings include: firstly, large seasonal fluctuations (peak: Nov./Dec.; trough: July/Aug.) in Lake Nasser's surface water levels (average annual fluctuations: from 3.7 m to 7.5 m), area (average area: 3622 km2 but up to 4530 km2), and volume (annual average: 13.4 km3, and up to 34 km3) are observed throughout years 2006 to 2015. These fluctuations are accompanied by an increase in GRACETWS (average: 50 ± 13 mm/yr, up to 77 ± 18 mm/yr) over Lake Nasser and by a progression of a front of increasing GRACETWS values (>50 ± 13 mm) away from the lake reaching distances of up to 700 km some 2 to 4 months following peak lake level periods. The areas witnessing the seasonal increase in GRACETWS display a progressive increase in phase and decrease in amplitude with distance from the lake. Secondly, the negligible precipitation over the Dakhla subbasin cannot account for the observed seasonal GRACETWS patterns and neither can the leakage signal from Lake Nasser. Thirdly, overall similarities in the distribution of GRACETWS seasonal spatial patterns are observed. During high lake level periods (July to Dec. 2007; Aug. to Feb. 2015) additional, and more distant, areas from Lake Nasser saw increases in GRACETWS and vice versa during low lake level periods (e.g., Aug. to Feb. 2015; Aug. to Nov. 2010, respectively). These observations are consistent with Lake Nasser being a main source of modern recharge for the Dakhla subbasin and suggest a new conceptual model for the NSAS: a slow groundwater flow through a porous matrix and a rapid groundwater flow along a network of faults, fractures, and karst topography across the matrix. We suggest that the proposed conceptual model for the interaction between Lake Nasser and the Dakhla subbasin could be applicable to aquifers of similar geologic, climatic, and hydrologic settings worldwide and that approaches similar to those advocated here could be used to investigate the validity of this suggestion.

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关于湖泊-含水层相互作用，GRACE 季节周期可以告诉我们什么？

摘要 几十年来，湖泊-含水层相互作用一直是调查和辩论的主题。传统的调查方法包括测量地下水-地表水界面的水通量、应用热量和环境示踪剂方法、对水流进行数值模拟以及基于质量平衡的方法。我们首先审查、评估和描述已应用于检查湖泊-含水层相互作用的不同方法，并提出了一种额外的补充方法。虽然现有方法可以很好地表征湖泊泄漏及其通过多孔介质（层流）的缓慢移动，但对通过首选路径（断层/岩溶）的快速湍流进行建模仍然是一项具有挑战性的任务。为了更好地了解湖泊-含水层相互作用的性质和范围，并使用纳赛尔湖和埃及西部沙漠（面积：0.66 × 106 平方公里）的努比亚砂岩含水层系统 (NSAS) 的下伏达赫拉子盆地作为测试地点，我们在时间和空间上检查、建模和关联，在重力恢复和气候实验陆地储水 (GRACETWS) 解决方案中，包括降水、湖泊水位、面积和水量。我们回顾了当前 GRACE 在水文学中的应用并展示了我们的新方法。调查结果包括：第一，纳赛尔湖地表水位季节性波动较大（高峰：11 月/12 月；低谷：7 月/8 月）（年平均波动：从 3.7 m 到 7.5 m），面积（平均面积：3622 平方公里） 2006 年至 2015 年期间观测到的最大面积为 4530 平方公里）和体积（年平均值：13.4 平方公里，最多 34 平方公里）。这些波动伴随着纳赛尔湖上 GRACETWS 值的增加（平均：50 ± 13 毫米/年，高达 77 ± 18 毫米/年）以及 GRACETWS 值增加（> 50 ± 13 毫米）的前沿进展在湖泊水位高峰期之后的大约 2 到 4 个月，从湖泊到达长达 700 公里的距离。见证 GRACETWS 季节性增加的区域随着与湖的距离的增加，相位逐渐增加，振幅逐渐减小。其次，达赫拉子流域上可忽略的降水不能解释观察到的季节性 GRACETWS 模式，纳赛尔湖的泄漏信号也不能解释。第三，观察到 GRACETWS 季节性空间格局分布的总体相似性。在高湖水位期间（2007 年 7 月至 12 月；2015 年 8 月至 2 月），更远的距离，在低湖水位期间（例如，分别为 2015 年 8 月至 2 月；2010 年 8 月至 11 月），纳赛尔湖地区的 GRACETWS 增加，反之亦然。这些观察结果与 Nasser 湖是 Dakhla 流域现代补给的主要来源一致，并为 NSAS 提出了一个新的概念模型：缓慢的地下水流过多孔基质，快速的地下水流沿着断层、裂缝和整个矩阵的喀斯特地形。我们建议，纳赛尔湖和达赫拉流域之间相互作用的拟议概念模型可适用于世界范围内具有相似地质、气候和水文环境的含水层，并且可以使用与此处提倡的方法类似的方法来研究该建议的有效性.