【摘要】 河水-地下水交互作用对河流水质净化、流域水生态健康和河岸土地合理规划具有重要意义.本文以广州市流溪河为研究对象,实时监测河水和河岸带地下水基本理化指标并采集水样和土样进行水体主离子、氮形态、金属离子浓度、氘（δD）氧(δ¹⁸O)同位素和土壤渗透系数（K）测试分析.结果表明:监测期间以河水侧向补给地下水为主,对地下水水位的影响范围在距河岸10 m内;距河岸1 m处地下水溶解氧（DO）浓度、电导率（EC）和氧化还原电位（ORP）变化明显,变异系数（n=7）分别为30.9%、42.0%和44.4%.河水和河岸带地下水水化学类型均为HCO₃-Ca型,受碳酸盐岩风化控制.河水入渗补给地下水初期,河岸带含水层向还原环境转化（ORP平均下降92.25 mV）,非饱和带Mn氧化物发生还原性溶解,地下水中Mn²⁺浓度逐渐增加并达最大值(0.52 mg·L^-1);基于δD、δ¹⁸O和Cl^-浓度的混合模型估算的河水对距河岸5 m处地下水的贡献率分别为10.4%、11.6%和11.5%,表明监测断面河水-地下水交互边界约在距河岸5 m处.更多还原

【Abstract】 River-groundwater interaction in riparian zone is of great importance for purification of river water, aquatic ecological health and optimal planning of riparian soils. The Liuxi River was selected to monitor physicochemical parameters of river water and groundwater, which were collected at an interval of 4 hours for the determination of major ions, nitrogen forms, metal ions, δ¹⁸O and δD. The results show that the lateral recharge of river water to groundwater predominated during the monitoring periods, leading to the water table of groundwater being fluctuated within the distance of 10 m from the river bank. Distinct changes in DO concentration, EC, and ORP were observed with coefficients of variation（n=7） of 30.9%, 42.0%, and 44.4%, respectively, at site with a distance of 1 m from the river bank. The hydrochemical type of river water and groundwater in riparian zone is HCO₃-Ca, resulting from the weathering of carbonate rocks. Early infiltration of river water induced a reducing environment with an decreasing ORP in the aquifer of riparian zone. Furthermore, Mn²⁺ concentration in groundwater gradually increased due to reductive dissolution of Mn oxides. At the distance of 5 m from the river bank, the contribution rates of river water to groundwater were estimated as 10.4%, 11.6% and 11.5% by a two end-members mixing model based on δD, δ¹⁸O, and Cl^- concentration, indicating that the boundary of river-groundwater interaction in riparian zone is approximate 5 m far from the riverbank.更多还原