京津冀西北典型流域地下水化学特征及补给源分析

为揭示京津冀西北典型流域地下水循环特征,运用环境同位素和水化学技术等方法分析张家口市不同流域水体氢氧同位素特征、水化学特征及时空变化特征、地表地下水转化关系。结果表明：地表水化学类型主要为HCO₃-Mg·Na和HCO₃·Cl-Na型;地下水化学类型不同时期表现出不同的类型,水化学类型更为多样,主要以HCO₃-Mg·Na型、HCO₃·Cl-Na型、HCO₃·Cl-Na·Mg为主。地表河水和地下水中离子均主要来源于岩石风化作用;张北和桑干河流域地下水中离子偏向于蒸发浓缩作用控制。张家口市各流域地表地下水δ¹⁸O、δD组成较为接近,表明了当地地表水和地下水均受到大气降水的补给。大气降水和地表河水对地下水的补给比例均值分别为37.74%和62.26%,以地表河水的补给为主要方式。

Hydrochemistry characteristics and the recharge source of groundwater in typical watersheds of Beijing-Tianjin-Hebei region,China

To reveal the characteristics of groundwater circulation in typical watersheds of the northwestern Beijing-Tianjin-Hebei region, this paper used environmental isotopes and hydrochemical techniques to analyze the characteristics of hydrogen and oxygen isotopes, hydrochemical characteristics and spatio-temporal changes, as well as the relationship between surface water and groundwater transformation in different watersheds of the Zhangjiakou region. Results showed that the surface water in the region was mainly HCO₃-Mg·Na and HCO₃·Cl-Na type, while in different seasons the water types of the groundwater were not the same. Specifically, the groundwater types were more diverse with HCO₃-Mg·Na, HCO₃·Cl-Na, HCO₃·Cl-Na·Mg types. An ion source analysis indicates that the surface water and groundwater were mainly affected by rock weathering. Parts of the groundwater in Zhangjiakou were affected by evaporation concentration. The hydrogen and oxygen isotopic compositions of surface water and groundwater were similar, indicating that the water was mainly from the atmospheric precipitation. Based on stable isotopic characteristics, 37.74% of the groundwater in the study region was derived from precipitation, while the remaining 62.26% was from river water, suggesting that the basin groundwater is mainly recharged from the river water.