北京房山应急水源地地下水数值模拟及河流渗漏量预测

Numerical Modeling of Emergency Karst Groundwater Well Field and Prediction of Variations of River Seepage in Fangshan District,Beijing

以北京房山岩溶水应急水源地为例,采用等效连续介质体概化地下水流系统,建立地下水流数值模型,评价地下水源汇项,分析地下水系统特征。运用MODFLOW中的河流(渠)子程序包,刻画地表河流和泉水与地下水的交换关系。经参数识别和验证,计算结果与实测数据拟合较好,能够比较准确的模拟水源地岩溶水系统。模拟和预测结果表明,水源地地区地下水与地表水联系密切,应急开采后,地下水系统由向河流排泄转变为河流渗漏补给地下水,可为应急水源地合理开发利用提供科学依据。

In order to evaluate the emergency karst groundwater well field in Fangshan District,Beijing,the numerical model of groundwater flow was established on the basis of the conceptualized equivalent continuous medium.The simulation of groundwater interaations with river and spring were executed by using the sub-programs river and drain packages of MODFLOW.The simulated results are reasonable by comparing the simulated groundwater tables with the observed processes.Simulated and predicted results indicate that groundwater are closely connected with surface water in emergency karst groundwater well field areas.After the emergency extraction,the river changes from the groundwater system discharge into the river to recharge groundwater.The results can provide the basis for rational development and utilization of emergency karst groundwater well field.