基于水功能区划的河流生态环境需水量计算研究

以北运河为例,根据河流功能区划及河流特点,基于分时段、分区域、分等级的思想,综合采用Tennant法、水质模型法、鱼类生境法进行北运河流域生态环境需水量计算,得出北运河各功能区河段的最小、适中、最佳生态需水量。研究结果表明:沙河闸—北关闸、北关闸—杨洼闸的河段水污染严重,仅依靠增加基流量无法满足河流水质功能要求,需要在满足河道一定基流的基础上最大程度削减河段的污染物排放量;土门楼—筐儿港、筐儿港—屈家店河段,采用鱼类生境法计算河道生态环境需水量分别为2.581亿m3/a、3.016亿m3/a,此水量是该河段恢复河流生态结构与功能健康的最佳需水量。

Calculation Research on River Eco-Environmental Water Requirements Based on Water Function Regionalization

With the Beiyunhe River an example,in terms of river function regionalization and river characteristics and based on the ideas of time section,regional section and stage division,such comprehensive methods as Tennant method,water quality model method and fish habitat method are adopted to carry out water requirement calculation of eco-environs in the North canal valley,whereby obtaining the minimum,moderate and the optimal eco-water requirements for each functional region river section of the Beiyunhe River.It can be known via calculation analysis that water pollution is serious in the river sections of Shahe Gate—Beiguan Gate,Beiguan Gate—Yangwa Gate.Accordingly,only by relying on increasing base flow,three is no way to satisfy the functional requirements of the river water quality,it is necessary to eliminate the pollutant emission to the maximum extent in the river section based on the base flow in the river course.Therefore,fish habitat method should be adopted to calculate water requirements of river course eco-environs,which are 25 810 000m3/a and 30 160 000 m3/a at Tu Menlou Gate—Kuang Ergang Gate,Kuang Ergang Gate—Qu Jiadian Gate respectively.This flow is the optimal water requirement for the restoration of river eco-structure and health function of that river section.