基于城市水生态系统健康的生态承载力理论探讨和评价研究

Theoretical discussion and assessment of eco-bearing capacity based on the healthy urban water ecosystem

城市水生态系统是城市生态系统的主要组成部分和关键因素。通过城市水生态系统与人体自身健康机制的类比分析,将基于城市水生态系统健康的生态承载力定义为在一定社会经济条件下,城市水生态系统维持其服务功能(供水、防洪、生物保护、景观娱乐等)及自身健康的潜在能力。提出了“基于城市水生态系统健康的生态承载力-压力量化模型”,并根据理论模型设计了计算模型。用承载力与压力所确定的城市水生态系统健康指数,描述了城市水生态系统的健康状态。以郑州市为例,分别计算了该市1995—2004年城市水生态系统承载力及其压力,并得出相应的城市水生态系统健康指数。结果表明,城市水生态系统承载力处于逐年上升趋势,但存在波动;健康指数亦逐步增加,对应健康状态为“病态—亚健康—健康”状态,特别是1998年后该地城市水生态系统健康状况有明显好转。

The present paper is aimed at introducing a quantitative model of Urban Water Eco- bearing Capacity （UWEBC）--the pressure, based on which a corresponding calculating model is devised. As is known, urban water ecosystem is the main part or the key factor of the urban ecosystem. For our research purpose, we have first of all made a comparative study between the urban water system and human body health mechanism, and then defined the Urban Water Eco-bearing Capacity （UWEBC） as a potential ability for water ecosystem to maintain its service function （water supply, flood-resistance, creature protection and landscape entertainment, etc. ） and its own health in a specific social and economic condition. Taking the city of Zhengzhou as an example, the author has made detailed calculation of its UWEBC and pressure between 1995 to 2004 along with its urban water ecosystem health indexes of each year. From our calculation it can be concluded that the water ecosystem bearing capacity has increased year after year and the social pressure also tends to mount on with occasional fluctuations. Although the UWEHI of the city increases gradually and the relative health state changes from poor state to nearhealthy one and later turns to rather a rather healthy one. Especially after 1998, the city＇s ecosystem health state witnessed a remarkable improvement. Thus, it can be said that, since 1995, the urban water ecosystem has been developing more or less harmoniously. This research, however, can be expected to provide a reference to further ecology environment construction.