The spatiotemporal characteristics of hydrogen and oxygen stable isotopes of Baimai Spring Group
Background,aim,and scope Investigating the recharge source of spring water has great guidance for water resource management and sustainable development.The isotopic tracers is an effective approach for investigating complex hydrological processes of spring water.At present,the research on Baimai Spring mainly focused on the water yield and seasonal variation,and its recharge source is not clear.Therefore,this study reveals the recharge source of the spring by studying the stable isotope composition of the springs in Baimai Spring Group.The results would provide guidance for water resource management and sustainable development of tourism of the Baimai Spring Group.Materials and methods Spring water samples were collected monthly from Aug.2017 to Jul.2018 at 6 locations.During the sampling period,a total of 50 samples were collected.Hydrogen and oxygen stable isotope values(δ2H and δ18O,respectively)of spring water were measured using a Los Gatos Research liquid water isotope analyzer(IWA-45EP).The local meteoric water line and evaporation line of spring water were analyzed and used to investigate the recharge sources of Baimai Spring Group.Results The values of δ2H and δ18O of precipitation ranged from-151.55‰ to-4.28‰,and from-19.93‰ to-0.52‰,respectively.The LMWL was δ2H=7.58×δ18O+4.17.The δ2H of spring water in the Baimai Spring Group ranged from-65.23‰ to-37.01‰,and the δ18O ranged from-8.99‰ to-4.04‰.Most of the isotope points of spring water were present close to the LMWL;the LEL of spring water was simulated as δ2H = 5.75×δ18O-13.23,where the slope of LEL(5.75)was lower than that of the LMWL(7.58).Discussion Although the monthly δ18O of each spring exhibited similar patterns,the slopes of LEL and initial isotope of each spring were different,indicating that the recharge altitudes and paths of spring water were different and complex.Considering the effect of altitude on δ18O in precipitation,the recharge altitudes of each spring water were higher than the altitude of Yiyuan County(precipitation sample site,298 m),and the recharge altitude of spring water was in the order of Baimai and Dongmawan springs＞Moquan and Meihua springs＞Shaizi and Longwan springs.Conclusions The spring water of the Baimai Spring Group was primarily recharged by local precipitation that had undergone varying degrees of evaporation before infiltration into the ground.The recharge altitudes and paths of each spring were different and complex.Recommendations and perspectives Due to the restricts of terrain,stratum,lithology,and precipitation,the hysteresis effect of isotopes of spring water on precipitation was obvious,but the recharge period of spring water would be further determined by using isotope dating methods and hydrogeological conditions.
stable isotopes of hydrogen and oxygenthe local meteoric water linethe local evaporation linerecharge sourceBaimai Spring Group
万方数据
维普
