Liu Wuyi¹  ShaoDongguo¹ Xu Huanyan²

(1.State Key Laboratory of Water Resources & Hydropower Engineering Science, Wuhan University, Wuhan, 430072£»2. Foreing languages department of North China Institute of WaterConservancy and Hydroelectric Power£¬Zhengzhou£¬450045)

Abstract:The urban water ecosystem is the main and key factor of the urban ecosystem. By a comparative study between urban water system and human body health mechanism, the article defines Ecological Carrying Capacity on the basis of urban water health system, and then presents the quantitative model of urban water ecosystem carrying capacity(UWECC)¡ªPressure, based on which its calculating model is devised, including Natural Carrying Capacity(NCC) and social reviving carrying capacity. On the basis of urban water ecosystem indexes between carrying capacity and pressure, the health state of urban water ecosystem is described. Taking the city of Zhengzhou as an example, the author analyzes the comparative relationship between urban water ecosystem carrying capacity and pressure in the local areas in different periods before making a reasonable assessment on the health state of the city¡¯s water ecosystem. It is concluded that due to increasing the investment of environment construction and protection since 1995,the health state of the city¡¯s ecosystem has improved remarkably, the economy develops harmoniously with the urban water ecosystem.

Key words: urban water ecosystem health, ecological carrying capacity£¬assessment