中文摘要：

随着人类社会的发展进步及城市化进程的加快,人类活动对水资源的需求日益增加.水循环也从最初的自然水循环演变成＂自然-社会＂二元水循环.二元水循环理论的提出,为水文水资源学科的发展指明了新方向.迄今为止仍然没有统一的数理公式对二元水循环过程进行精确描述.本研究以城市为重点,深入剖析了社会经济用水需求对水循环的干扰和驱动原理,通过类比物理学中的麦克斯韦方程组,初步定义了城市水资源需求场——＂水场＂的概念,提出了城市＂水场＂强度的计算公式.以海河流域22个主要城市为例,应用水场强度计算公式定量描述了海河流域的水场强度,分析了水资源的流动趋势.结果表明,水场强度公式能够较好地描述城市水资源的驱动力和流动趋势.

英文摘要：

With the rapid development and progress and the urbanization of human society, the demand for water of human activity is increasing. In the development of human society, with the climate changing and human activities increasing, water shortages have become increasingly prominent. The amount of water in some areas cannot be guaranteed, as well as a sharp deterioration in water quality. With the acceleration of urbanization, urban water demand is increasing. The water resources in the natural water cycle which are supplied for the city are not enough. Thus, in various urban water supply and water diversion projects, water is transported to the city, with the purpose of supplying water for the city production and life. Water cycle has also evolved from the original natural water cycle to dualistic nature-social water cycle. The dualistic water cycle theory indicates a new direction for the development of hydrology and water resources disciplines. So far there is still no uniform mathematical formula that can accurately describe the dualistic water cycle. In this study, we try to explore the mathematical and physical foundation of dualistic water cycle. We focused on the cities and did the in-depth analysis of the interference and driving principle of the socio-economic water demand on the water cycle. By analogy in physics Maxwell equations, the urban water demand field-the concept of ＂water field＂ was preliminary defined. According to the concept of electric charge, we define the ＂water charge＂ as the water requirement intensity. In the progressive development of the city, the city is in the analogy of a point electric charge in electric field. The electric field is formed by the point electric charge, while the water demand field is formed by the urban water demand. Point charge electric field can be superimposed over each other, so the electric field strength is also superimposed. Also, the water field strength of each cities which are close can be superimposed, and the city group will attract the water r