Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, 210008 Nanjing, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China.
Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, 210008 Nanjing, China; Yangtze Institute for Conservation and Development, Hohai University, Nanjing 210024, China.
Sci Total Environ. 2023 Jan 20;857(Pt 2):159414. doi: 10.1016/j.scitotenv.2022.159414. Epub 2022 Oct 13.
Groundwater behaviors in lake-floodplain systems are dynamic and complex; in particular, the role of groundwater flux in regulating lake water storage subject to strong seasonal variation is not well understood. This study addresses the contribution of groundwater flux in a large floodplain system (Poyang Lake, China), with focus on quantifying the groundwater-lake interactions at multiple time scales in high rainfall (2010) and low rainfall (2011) years using a groundwater flow model (MODFLOW). Simulated results revealed that the unconfined aquifer received approximately 8 % of the annual rainfall as groundwater recharge. Fluctuations in shallow groundwater and lake water level reflected hydraulic synchronization and hysteresis. Additionally, the diurnal variability in the groundwater-lake exchange fluxes was subject to dynamic and bidirectional patterns, and a time lag between the water exchange and rainfall was also found. For 2010 and 2011, the monthly net flux of lake infiltration into groundwater was 1.5-10.0 mm and 0.1-6.0 mm and groundwater exfiltration into lake was 1.3-9.5 mm and 0.4-2.2 mm, respectively, demonstrating a significant variation of the exchange magnitude and direction. In particular, we found that groundwater exfiltration contributed up to 55 % of lake storage change in February of 2011. The outcomes from this study indicate that groundwater can be a major component of the Poyang Lake's water balance, which suggests an important role of groundwater in regulating the lake water storage and perhaps other flood pulse systems.
湖泊-泛滥平原系统中的地下水行为是动态且复杂的；特别是，在强季节性变化下，地下水通量在调节湖泊储水量方面的作用还没有得到很好的理解。本研究针对一个大型泛滥平原系统（中国鄱阳湖）中的地下水通量进行了研究，重点是利用地下水流动模型（MODFLOW）在高降雨量（2010 年）和低降雨量（2011 年）年份量化多个时间尺度上的地下水-湖泊相互作用。模拟结果表明，无压含水层接收了约 8%的年降雨量作为地下水补给。浅层地下水和湖泊水位的波动反映了水力同步和滞后。此外，地下水-湖泊交换通量的日变化受到动态和双向模式的影响，并且在水交换和降雨之间存在时间滞后。对于 2010 年和 2011 年，每月湖水入渗补给地下水的净通量分别为 1.5-10.0mm 和 0.1-6.0mm，地下水渗出补给湖水的净通量分别为 1.3-9.5mm 和 0.4-2.2mm，表明交换量和方向有显著变化。特别是，我们发现地下水渗出补给对 2011 年 2 月的湖泊储水量变化贡献高达 55%。本研究的结果表明，地下水可以成为鄱阳湖水量平衡的主要组成部分，这表明地下水在调节湖泊储水量方面可能起着重要作用，也许对其他洪水脉冲系统也是如此。
