Hohai University, 1 Xikang Road, Nanjing 210098, China.
Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
Sci Total Environ. 2022 Dec 20;853:158558. doi: 10.1016/j.scitotenv.2022.158558. Epub 2022 Sep 8.
Groundwater and surface water are hydrologically interconnected systems that exhibit dynamic water, heat and mass exchanges. In this study, a conceptual framework was used to investigate groundwater behaviors and associated hydrological exchanges by combining field measurements, digital filtering and analytical approaches, exemplified by a linked catchment-floodplain-lake system (Poyang Lake, China). The results show that the hydrological regime for both groundwater and surface water exhibit a seasonal variability in the lake catchment. Topographically, the lake catchment can be divided into the mountainous baseflow, ungauged lateral groundwater and floodplain groundwater that contribute to the lake storage changes. Although groundwater flow is generally from the mountainous catchment to the lake floodplain areas due to topographic effects, precipitation provides an additional input for the shallow groundwater and is expected to enhance the groundwater dynamics in terms of spatially heterogeneous responses. The estimation indicates that about 40 % of the catchment river discharge may be coming from the mountainous baseflow (290 × 10 m/yr) and discharged into the lake through a surface flow pathway. The ungauged groundwater-lake interaction shows the annual discharge volume is up to 10 × 10 m/yr and associated exchange fluxes tend to be stronger during spring-summer months (23-45 m/s) than those of autumn-winter months (9-22 m/s). Additionally, the floodplain groundwater-lake exchange (9.5 × 10 m/yr) indicates that groundwater generally receives the lake water during summer months (mean flux = 110 m/s) and discharges into the lake during other months (90 m/s) through a subsurface pathway. This study highlights the importance of groundwater's contributions to the surface river-lake system in terms of the flux variability and different transport pathways. The outcomes of this work will benefit future water resources management and applications by providing a methodology for predicting the groundwater hydrology of large lake-catchment systems.
地下水和地表水是水文上相互连接的系统，表现出动态的水、热和物质交换。本研究通过结合野外测量、数字滤波和分析方法，使用一个集流域-泛滥平原-湖泊系统（中国鄱阳湖）为例，建立了一个概念性框架来研究地下水行为和相关的水文交换。结果表明，流域地下水和地表水的水文状况都表现出季节性变化。从地形上看，流域可分为山区基流、未测量的侧向地下水和泛滥平原地下水，它们共同导致湖泊储水量的变化。尽管由于地形效应，地下水通常从山区流域流向湖泊泛滥平原地区，但降水为浅层地下水提供了额外的补给，并有望在空间异质响应方面增强地下水动态。估计表明，约 40%的流域河流径流量可能来自山区基流（290×10 m/yr），并通过地表水流路径排入湖泊。未测量的地下水-湖泊相互作用表明，年排放量高达 10×10 m/yr，且春季-夏季（23-45 m/s）的交换通量比秋季-冬季（9-22 m/s）更强。此外，泛滥平原地下水-湖泊交换（9.5×10 m/yr）表明，地下水通常在夏季从湖泊接收水（平均通量=110 m/s），并在其他月份通过地下途径排入湖泊（90 m/s）。本研究强调了地下水对地表河流-湖泊系统的重要性，包括通量变化和不同的输运途径。这项工作的结果将通过为预测大型湖泊流域系统的地下水水文学提供方法，为未来的水资源管理和应用带来益处。
