城市绿地生态系统合理供水辨识分析

Rationality Analysis of Water Resources Supply for Urban Green Space

城市绿地因具有美化环境、降低空气污染、控制城市热岛等作用而日益得到重视。合理的城市生态供水不仅有益于植被的正常生长,对城市水资源合理配置同样具有积极意义。为统筹城市生态与国民经济发展,保证绿地健康,需要合理的绿地供水管理。本文以土壤含水量为标准,根据田间持水量、临界土壤含水量和凋萎系数三个土壤含水量值划分不同等级的绿地需水量,将供水量分为四个等级,建立了城市绿地供水合理性评价模型,为有效辨识供水合理性提供了参照依据。以2009年北京市城市绿地供水为例,进行了供水合理性分析,结果表明,从全年来看,供水基本合理,虽然绿地蒸散发受到一定抑制,但不影响植被生长;从逐月供水来看,个别月份存在供水过少或过多现象,影响植被生长,且不利于水资源合理利用。

Urban green space has become more important for the functions of beautifying the environment, reducing air pollution, controlling urban heat islands. Rational water supply quantity can keep plants growing well and be benefltial to the rational allocation of water resources. To plan well the ecosystem and economic development, keep green space healthy, rational water supply management for urban green space is in urgent need. A rationality analysis model of water resources utilization for urban green space was established. Based on field water containing capacity, critical soil water content and wilting coefficient, the water supply in the model was classified into four grades which provided criterions for identifying the rationality of water resource supply. Beijing was taken for an example to evaluate the urban green space water supply in the year of 2009. The results showed that for the whole year the supply was rational and plants＇ growth was not influenced although evapotranspiration was inhibited. However, in some months water supply was not enough or superabundant, which inhibited plants＇ growth and was not favorable to the rational utilization of water resources.