Proposal of groundwater conservation strategy based on the understandings of the groundwater flow system in North China Plain, China

为了解决水资源问题，需要实地调研工作和对实际情况的了解。我们对北京和天津地区进行了实地考察，调查了水资源状况。环境水的水质和同位素含量结果揭示了地下水系统符合地下水流动系统的概念。指出了冲积扇、冲积平原、海岸三角洲等地貌要素的水文作用。从社会经济因素和政府的农业政策等方面对水位下降问题进行了探讨。分析表明，人的维度对认识水位下降的影响具有重要意义。地下水资源的可持续利用必须建立在对水文循环的真实认识的基础上。它会告诉我们用水量的上限。如果我们加强水文循环，可用的水就会增加。南水北调工程是其中的一项措施，但必须考虑到用水系统不脆弱。

In order to resolve water problems, field-based research work and understandings of actual situation is necessary. We made field trips to Beijing and Tianjin area, and investigate for the conditions of water resources. The results of water quality and isotopic contents in environmental water reveal the subsurface water system consistent with groundwater flow system concept. It suggests the importance of hydrological function of the geomorphologic elements such as alluvial fan, flood plain, and coastal delta. The problem on the water level decline is discussed with the socio-economic factors and government policy for agriculture. The analyses showed the importance of human-dimension to understand the effect of water level decline. Sustainable use of groundwater resources should be based on the real understandings of hydrological cycle. It will tell us the upper limit of water usage. If we strengthen the hydrological cycle, the available water will be increased. The south to north water transfer project is one of the measures, however the consideration is necessary for water use system be not vulnerable.