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2014年6月和2015年1月,在西江各干流和支流分别采集了54个水样,对水的氢氧同位素组成进行了分析.结果表明,西江水体δ18O和δD存在明显的线性关系,这种相关关系旱季显著于雨季,西江水体旱、雨季18O、D值均沿大气降水线分布.氘盈余(d)值雨季大于旱季,主要是由于雨季降水多通过落水洞、竖井、漏斗等岩溶形态直接补给地下河,与围岩接触的时间较短,而旱季降雨较少,地表河系统受储存在岩溶裂隙、孔隙中的地下水体补给.由于受海拔高度及蒸发效应的影响,西江干流红水河—浔江段和支流右江—郁江段δ18O和δD值整体上表现为沿流程逐渐偏正的趋势,而由于桂江支流上游到下游海拔差异不大,流程简短、加上桂江支流水量少于西江干流和右江—郁江支流,桂江支流未出现从上游到下游逐渐偏正现象.通过δ18O与高程的关系建立了二者之间的线性回归模型,揭示了雨季西江水体随高度的变化率为:-0.44‰·(100 m)-1,旱季为-0.45‰·(100 m)-1,反映西江流域降水的高度效应,这对流域水循环过程的研究具有重要的水文地质意义.
In June 2014 and January 2015, 54 water samples were collected from each of the mainstream and tributaries of the Xijiang River to analyze the hydrogen and oxygen isotopic compositions of water. The results show that there is a clear linear relationship between δ18O and δD The correlation between dry season is significant in the rainy season, Xijiang water body drought, rainy season 18O, D values are distributed along the atmospheric rainfall line .Deuterium surplus (d) value of the rainy season is greater than the dry season, mainly due to precipitation in the rainy season through the water hole, shaft, funnel and other karst morphology Directly recharged the underground river, contacted with the surrounding rock for a short time and had less rainfall during the dry season, and the surface river system was recharged by groundwater bodies stored in karst fissures and pores.Due to the influence of altitude and evaporation, The δ18O and δD values of the Yijiang-Yujiang section and the Youjiang section of the Yijiang-Yujiang section show a trend of becoming more and more normal along the process. However, due to the small difference between upstream and downstream of the tributaries of the Guijiang River and the short process, Less than the mainstream of the Xijiang River and the Youjiang-Yujiang tributaries, the tributaries of the Guijiang River did not appear to be gradually shifting from the upper reaches to the lower reaches. A linear regression model was established between the δ18O and the elevations, revealing that the rain The seasonal variation rate of the Jixi River was -0.44 ‰ (100 m) -1 and -0.45 ‰ (100 m) -1 in the dry season, which reflected the height effect of precipitation in the Xijiang River Basin. The research on the water cycle in the Jixi River has the following features Important hydrogeological significance.