塔里木河流域地表水和地下水的转化关系

Transformation Relationship Between Surface Water and Groundwater in Tarim River Basin

[目的]探究塔里木河流域地表水和地下水的转化关系,为该流域水资源形成机制研究和促进水资源合理开发利用提供科学依据。[方法]以氧同位素(δ^(18)O)作为示踪剂,采用稳定同位素技术和水化学原理分析了塔里木河流域地表水与地下水转化关系。2018年沿塔里木河上、中、下游采集了90组地表水样和地下水样,并测量相应的氘氧稳定同位素和水化学离子(Cl^(-),SO^(2-)_(4),HCO^(-)_(3),Ca^(2+),Mg^(2+),Na^(+)),运用Gibbs图和Piper三线图探测了塔里木河流域地上和地下水化学特征及其转化关系。[结果]①地下水和河水的δ^(18)O值具有不同的变化情况:地下水δ^(18)O值随着流向呈现明显的逐渐富集特点,而地表水则变化较小。通过总溶解固体(total dissolved solids,TDS)的沿程分析可知,对于上游地下水而言,由于河水下渗补给,加上侧向径流影响,δ^(18)O呈现了大幅下降。随着河水补给的增加,其值不断富集。对于地表水而言,随着流向其δ^(18)O值逐渐下降,此时地下水呈现富集,说明此时期地下水能够对地表水产生补给。②根据地下水和河水测试数据分别建立地下水线和河水线方程,且二者斜率均小于大气降水线斜率,说明地下水和河水同位素组成受到一定程度蒸发作用影响。③塔里木河上游地下水向地表水补给平均速率为1.76 m^(3)/(d·m),中游地下水向地表水补给平均速率为1.71 m^(3)/(d·m),下游地下水向地表水补给平均速率为1.65 m^(3)/(d·m)。[结论]地表水—地下水的频繁转化是塔里木河流域水资源循环的主要特征,地下水补给是河流水资源的主要补给来源。

[Objective]The transformation relationship between surface water and groundwater in Tarim River basin was explored,in order to provide scientific basis for the research on the formation mechanism of water resources and the promotion of rational development and utilization of water resources.[Methods]Using oxygen isotope(δ^(18)O)as the tracer,the relationship between surface water and groundwater transformation in the Tarim River basin was analyzed by using stable isotope technique and hydrochemical principle.In 2018,about 90 groups of surface and underground water samples were collected along the upper,middle and lower reaches of the Tarim River,and their deuterium oxygen stable isotopes and hydrochemical ions(Cl^(-),SO^(2-)_(4),HCO^(-)_(3),Ca^(2+),Mg^(2+),Na^(+))were measured.Gibbs diagram and Piper trigram were used to explore the chemical characteristics and their transformation relationship between surface and underground water in the Tarim River basin.[Results]①Theδ^(18)O values of groundwater and river water varied differently.For groundwater,theδ^(18)O values gradually enriched along with the flow direction,while theδ^(18)O values changed little in surface water.According to total dissolved solids(TDS)analysis along the river,for the upstream groundwater,due to the infiltration and recharging of the river and the influence of lateral runoff,itsδ^(18)O decreased significantly.With the increase of the recharging of the river,itsδ^(18)O value continued to enrich.For surface water,the value ofδ^(18)O gradually decreased with the flow direction,and the groundwater was enriched at this stage,indicating that the groundwater can replenish the surface water during this period.②The groundwater waterline and river water line were respectively established,both of which were lower than the slope of precipitation line,indicating that the isotopic composition of groundwater and river water was affected by evaporation to a certain extent.③The average rate of groundwater recharge to surface water in the upper reaches of Tarim River was 1.76 m^(3)/(d·m),and was 1.71 m^(3)/(d·m)in the middle reaches and 1.65 m^(3)/(d·m)in the lower reaches.[Conclusion]The frequent conversion of surface water and groundwater is the main feature of water resources cycle in Tarim River basin,and groundwater recharge is the main source of water resources.