陕西渭北东部岩溶地下水强径流带的环境同位素证据及其可更新性评价

Isotope evidence of strong runoff zones of karst groundwater in eastern Weibei,Shaanxi,China,and its renewability evaluation

环境同位素研究证实,陕西渭北东部岩溶地下水系统中部上王—西头—黑池一带为岩溶地下水强径流带,是渭北东部岩溶地下水的主要径流区域。强径流带内岩溶水积极参与现代水循环,平均滞留时间为51年,具有较强的更新能力。与此对应,14C的证据显示强径流带以南、以北及东南部的岩溶地下水具有万年以上的形成历史,属难以恢复的不可再生资源。同位素EPM模型计算表明,强径流带内隐伏岩溶水系统天然补给量为87.55mm/a,储存量为9.62×109m3/a,平均储水系数为0.029。以上结论均与水文地质勘探结果基本吻合。环境同位素的研究成果提供了岩溶地下水的循环强度和可更新性的直接证据,补充和丰富了岩溶地下水运动的重要信息,为定量评价研究区隐伏岩溶地下水资源的可更新性提供了关键性数据。

Environmental isotope study confirms that the strong runoff zone of karst groundwater in the Shangwang-Xitou-Heichi area in the middle part of the karst groundwater system in eastern Weibei, Shaanxi, is a main runoff area of karst groundwater in eastern Weibei. Karst water in the strong runoff zone takes an active part in the modem water cycle, with an average residence time of 51 years, and so has a relatively strong renewable capacity. ^14C evidence shows that the karst groundwater south, north and southeast of the strong runoff zone has a history of more than 10000 years belongs to an unrenewable resource. The isotope EPM model calculation indicates that the hidden karst water system in the strong runoff zone has a natural recharge rate of 87.55 mm/a, a storage capacity of 9.62 billion m^3/a and a mean storage coefficient of 0.029. The above-mentioned results are in the main in agreement with the results of hydrogeological exploration. The environmental isotope study offers direct evidence for the cycle intensity and renewability of karst groundwater, supplements and enriches information of karst groundwater movement and provides key data for the quantitative evaluation of renewability of hidden karst groundwater resources in the study area.