湖底地下水排泄与湖泊水质演化

Lacustrine groundwater discharge and lake water quality evolution

湖泊富营养化是当前全球范围内最为典型且严重的水环境问题之一,但过去偏重营养盐向湖泊的点源和面源输入评价,常常忽视地表水-地下水相互作用在湖泊水质形成与演化中的作用。总结了地下水-湖水相互作用模式,重点评述了地下水排泄过程对湖泊水文与水质影响的研究进展,对比了渗流仪测量、水量平衡、氡质量平衡、温度示踪、数值模拟等量化方法的优劣性与适用性,探讨了地下水向湖泊排泄的时空变异性、地下水-湖水界面氮磷的迁移转化等难点问题的研究现状,提出该领域未来研究方向主要包括:综合运用多种技术方法,表征湖底地下水排泄的时空变异性;揭示界面水文生物地球化学过程,量化地下水向湖泊排泄氮磷负荷;评估强烈人类活动改造对地下水-湖水相互作用的影响。

Lake eutrophication is one of the most typical and serious water environmental problems in the world, and input of both point-source and non-point source nutrients into lake has been the focus of previous studies.However, the role of surface water-groundwater interactions in the occurrence and evolution of lake eutrophication has been often neglected.In this paper, the patterns of groundwater-lake water interactions were summarized, the research progress on the influence of groundwater discharge on the hydrology and water quality of lake were reviewed, and the advantages and applicability of different quantifying methods such as seepage meter measurement, water balance, radon mass balance, temperature tracing, and numerical simulation) were compared.The state-of-art of the studies and major challenges in understanding the spatial-temporal variability of groundwater discharge to lakes, and the transport and transformation of nitrogen and phosphorus at the groundwater-lake interface were reviewed.And three directions for the future study in this field were proposed: 1) characterizing the spatial-temporal variability of lacustrine groundwater discharge using multiple methods;2) accurately quantifying the loads of nitrogen and phosphorus with groundwater discharge into lakes, on the basis of revealing hydrobiogeochemical processes at the interface;and 3) unraveling the effect of strong anthropogenic activities on groundwater-lake interactions.