湖泊生态环境需水量计算方法研究

A study on the calculation methods of the minimum eco-environmental water demand for lakes

中国北方干旱和半干旱地区湖泊面临不断干枯、萎缩和水质污染严重的局面。水资源的不合理配置和使用,造成资源性缺水和水质性缺水;维护湖泊和水库的合理水位及其水体的自净能力已经成为淡水资源科学配置和永续利用的基本保证。确定和保证湖泊生态系统必需的最小水量是解决问题的关键和前提,计算湖泊最小生态环境需水量的方法有:①水量平衡法;②换水周期法;③最小水位法;④功能法。研究结果表明:对于受损严重的湖泊,功能法无论从理论基础、计算原则和计算步骤,还是从需水量的分类和组成,都比较准确地反映了湖泊生态系统的健康现状和湖泊生态系统需水量之间的相互关系,可以为防止湖泊生态系统日益恶化的趋势和生态恢复提供技术支持。针对不同类型湖泊、生态环境特性和生态系统管理目标可以选择不同的计算方法,在确定了湖泊最小生态环境需水量和生态环境建设实施方案,北方地区湖泊生态系统将进入科学管理和生态恢复阶段。

In arid and semi-arid areas of northern China,lakes have been facing a number of problems such us dried-up,shrinkage and serious water pollution.Non-scientifical utilization and management of the lake resources has resulted in water shortage and water quality degrada-tion.To keep rational water level and self-purification ability of the lakes is the guarantee for scientific and sustainable utilization of the water resources.The calculation method of the mini-mum eco-environ mental water demand for lakes is the basic precondition to keep rational uti-lization and management of the lake ecosystem.Based on the analysis of the crisis of lake eco-environment and the obstacles to the solution of the problems in China,the concept and calcula-tion methods about the minimum eco-environmental water demand for lakes have been analyzed.According to the feature s and actual situation of the minimum eco-environmental water demand for lake ecosystem s we put forward the calculaton methods:(1)water quantity balance method;(2)exchange water cycle method;(3)minimum water level method;and(4)function method.The results show that the function method can reflect exactly the relationship s between the healthy state and the minimum eco-environmental water demand of the lake ecosystems.This can offer technical support against the trend of eco-environmental deterioration and for the restoration of the lake ecosystems.These different methods should be used for different kinds of and different eco-environmental characters of the lake ecosystems.To define the minimum eco-environmental water demand for lakes,it is possible to offer scientific support for lake ecosystem management and restoration.In northern China the lake ecosystems will get into the new period of scientific management and ecological restoration after the minimum eco-environmental water demand for lake ecosystem s is determined and implement eco-environmental construction planning is imple-mented.