Determination of groundwater recharge rates in the North China Plain using

半干旱的华北平原人口稠密，水资源短缺，河流干涸和地下水位迅速下降就是明证。特别是地下水是一种重要的优质水资源，但数量有限，更新有限。该项目旨在通过将地球化学和地球物理数据与地下水动态综合模型相结合，为该地区宝贵的地下水资源的可持续管理提供关键信息。环境示踪剂（稳定同位素、14C、氚、惰性气体等）的分析能够确定地下水停留时间和补给率。数值地下水流动和运输模型，使集成的水力和示踪剂数据到一个具有预测能力的系统的机械视图。该项目建立在以前的工作的主要研究人员，谁建立了地下水模型和示踪剂数据集从石家庄地区，一个主要的补给区，但也是最严重的过度开采的部分NCP。该项目将联合收割机结合这两种方法，并将其扩展到整个NCP的规模，以便更好地了解补给率和机制。德国合作伙伴收集的示踪剂数据将提供不可或缺的地下水补给和年龄数据，以显著降低中国合作伙伴正在开发的模型的不确定性。相反，该模型为整合和解释德国合作伙伴收集的数据集提供了一个必不可少的工具。这一综合办法还将为与参加中德水资源联合倡议的其他研究小组建立联系提供许多机会，从与解释地下水示踪剂有关的地块尺度的非饱和区研究，到可与流域尺度的地下水模型联系起来的气候学和遥感数据。

The semi-arid North China Plain (NCP) is heavily populated and suffers from water scarcity, made evident by the drying-up of rivers and by rapidly falling groundwater levels. Especially the groundwater represents a vital water resource of high quality but finite quantity and limited renewal. This project aims to provide key information for the sustainable management of the precious groundwater resources in this area by integration of geochemical and geophysical data with a comprehensive model of the subsurface water dynamics. The analysis of environmental tracers (stable isotopes, 14C, tritium, noble gases, etc.) enables determination of groundwater residence times and recharge rates. Numerical groundwater flow and transport models enable the integration of hydraulic and tracer data into a mechanistic view of the system with predictive capabilities.The project builds on previous work of the principal investigators, who have established both a groundwater model and a tracer data set from the Shijiazhuang area, a major recharge area but also one of the most heavily overexploited parts of the NCP. This project will combine the two approaches and expand them to the scale of the entire NCP in order to arrive at a much better constrained and detailed understanding of the recharge rates and mechanisms. The tracer data gathered by the German partner will provide indispensible groundwater recharge and age data to significantly reduce the uncertainty in the model being developed by the Chinese partner. Conversely, the model provides an essential vehicle to integrate and interpret the data sets collected by the German partner. The combined approach will also offer many opportunities for links with other research groups taking part in the Sino-German joint initiative on water resources, ranging from studies of the unsaturated zone at the plot scale that are relevant for the interpretation of the groundwater tracers to climatological and remote sensing data that can be linked to the groundwater model on the basin scale.