长河流域δD、δ^(18)O特征及水体补给关系

Characteristics of δD and δ^(18)O in Changhe River Basin and Their Recharge Relationships

研究流域不同水体δD、δ^(18)O特征及补给关系,可以进一步弄清流域水循环特征。以长河流域为对象,对枯、丰两水期各水体δD、δ^(18)O组成及分布特征进行分析。结果表明:(1)大气降水是长河流域主要补给源之一,受蒸发作用影响,同位素分馏导致水体中δD、δ^(18)O呈现出“枯水期较丰水期富集”的特征。(2)流域氘盈余值表现出枯水期低、丰水期高的差异,两个时期地表水与浅层地下水均受到了蒸发与水-岩作用影响,且枯水期影响更加强烈。(3)流域上游主要是地表水补给浅层地表水,中游两水间在季节上存在交替补给现象,下游为浅层地下水补给地表水。

In order to further clarify the characteristics of water cycle in the basin,it is necessary to study the characteristics of δD and δ^(18)O in different water bodies and the recharge relationship in the basin.The Changhe River Basin was taken as the object to analyze the composition and spatial distribution of hydrogen and oxygen isotopes in different water bodies during dry and wet periods.The results show that:(1)Atmospheric precipitation is one of the main water supply sources in the Changhe River Basin.Due to the influence of evaporation,isotope fractionation leads to the characteristics of"enrichment of δD and δ^(18)O in the water column during dry season compared with wet season".(2)The deuterium surplus of the watershed shows a difference of low in dry season and high in wet season.Surface water and shallow groundwater are both affected by evaporation and water-rock interaction in both periods,and the impact is more intense during dry season.(3)The upper reaches of the basin are mainly recharged by surface water to shallow surface water,while the two waters in the middle reaches alternate seasonally,and the downstream is recharged by shallow groundwater to surface water.