河湖生态系统生态用水优化研究——以滇池流域为例

Estimating the eco-environmental water demand of a river and lake coupled ecosystem:a case study of Lake Dianchi Basin

生态需水是河流与湖泊生态系统健康的重要基础。湖泊流域的河流与湖泊生态系统之间存在密切的水量联系,目前对流域内生态用水的研究多为单一生态系统生态需水简单相加,忽略了河流和湖泊之间复杂的水量联系。基于河湖复合生态系统之间的水量联系构建了河湖生态系统生态用水优化模型,并以滇池为例分析了河湖生态系统生态用水规律。结果表明:湖泊流域中单一河流或湖泊生态需水计算结果不能满足复合生态系统的生态用水要求,需要综合考虑河流和湖泊之间的水量联系;在当前水质状况下,牛栏江每年的调水量不能满足滇池流域的生态用水要求;滇池流域水体污染对流域内生态用水影响较大,随着水体污染程度的下降,流域生态用水量和调水量呈指数下降,河流生态用水呈线性下降。

The environmental flow requirement is very important for the health of river and lake ecosystems.The sum of the environmental flow of river and the lake is often considered as the eco-environmental water demand of a river and lake coupled ecosystem in most studies.However,there may be problematic because the connection between the river and lake is ignored.Based on the water volume linkage between river and lake ecosystems,this paper constructed a watershed optimization model for a river and lake coupled ecosystem,and analyzed the eco-environmental water demand rules of watershed by taking Lake Dianchi as an example.The results showed that the environmental flow requirement of a single river or a lake could not meet the eco-environmental water demand of the lake basin,and the connection between rivers and lakes needed to be comprehensively considered.Under the current water quality conditions,the annual water transfer volume from Niulanjiang River cannot meet the eco-environmental water demand of Lake Dianchi Basin.The water pollution of Lake Dianchi Basin has a great impact on the eco-environmental water demand of river and lake coupled ecosystem in the basin.With the decrease of water pollution degree,the eco-environmental water demand for the whole system and water diversion in the basin decreases exponentially,and water use for river ecosystem decreases linearly.