基于氡同位素的河水与地下水水力交换研究

选取氡同位素(²²²Rn)作为地表水与地下水水力交换过程的天然示踪剂，探明不同河段多水源水力关联关系及海陵区水循环特征。对新通扬运河海陵段进行河水及附近地下水采样，定性分析河水与地下水水力联系过程，建立河道氡一维稳定流模型及流量平衡模型，定量辨识地下水入流和河水渗漏机制。结果表明，新通扬运河海陵段的地下水补给主要发生在R3~R4、R7~R9河段，支流汇入、汇出对干流影响较小。模拟的地下水入流和河水渗漏结果显示河道中存在河水和地下水相互作用。利用河道氡一维稳定流模型得到详细的河水与地下水的水力联系情况，所得结果与定性分析结果一致。河道氡一维稳定流模型中，上下游流量为特别敏感参数，上下游河水内氡活度浓度为比较敏感参数。

Study on hydraulic exchange of river water and groundwater based on radon isotope

This work selected ²²²Rn as a natural tracer to study the hydraulic exchange processes between the river water and the groundwater in Hailing section, Taizhou City. Samples of river water were collected from the Xintongyang Canal and samples of groundwater containing ²²²Rn were collected from the study area. The hydraulic relationship between river and groundwater was analyzed quantitatively. Based on a 1-D steady state model and a flow balance model, the groundwater inflow and the river water leakage were calculated separately. The ²²²Rn tracer results show that the groundwater inflow mainly occurred during two sections of the Xintongyang Canal, R3~R4 and R7~R9, and the tributaries had little effect on the ²²²Rn activity of river reach. Besides, there is an interaction between river and groundwater along the river. Furthermore, the results of the ²²²Rn method are consistent with the results in qualitative analysis. The upstream flow and downstream flow are the most sensitive parameters of the 1-D steady state model, while the ²²²Rn activity of river is a relatively sensitive parameter.