基于同位素技术的金衢盆地水循环研究

Water Cycle Analysis of the Jinqu Basin Based on Isotope Techniques

为查明金衢盆地各水体同位素特征,弄清各水体之间的相互关系,采集了研究区降水样品、具有代表性的地表水和地下水样品,通过对大降水中氘(D)、氧(18O)同位素的分析,建立了当地大气降水线,结合地表水及各类地下水稳定同位素特征,对金衢盆地水循环模式进行了分析。通过对氚(T)及14C同位素的分析对地下水的更新能力进行了评价。结果表明:金衢盆地降水线斜率及截距大于全球大气降水线的;地表水、松散层孔隙潜水及红层孔隙裂隙水主要接受大气降水补给;红层孔隙裂隙水接受松散层孔隙潜水的越流补给;环境同位素富集特征表明,地下水自盆地南北两侧向盆地中心流动;松散层孔隙潜水更新能力比红层孔隙裂隙水的强。

In order to ascertain the characteristics of stable isotopes in different water bodies and the relationship among water bodies in Jinqu Basin,precipitation samples were collected and representative surface water and groundwater samples were taken into account in the region.By analyzing the features of spatial distribution of the stable isotopes deuterium(2 H)and oxygen18(18 O),the local precipitation equation was established and the water cycle model was analyzed based on the stable isotope characteristics of surface water and groundwater in Jinqu Basin.The sustainable utilization of groundwater by enviromental isotope(3H)and carbon14(14C)was evaluated.The results show that the slope and intercept of the local precipitation line equation in Jinqu Basin are greater than the global precipitation line equation.Surface water,quaternary loose pore water and redbed pore fissure water are mainly supplied by precipitation.The cross flow of pore water in the quaternary loose layer supplies the redbed pore fissure water.The characteristics of environmental isotope enrichment indicate that the groundwater discharges from the north and south of the basin to the center of the basin.The sustainable utilization of quaternary loose pore water is stronger than that of redbed pore fissure water.