基于水质目标的人工生态湖运行方式研究

Study on Operational Mode of Artificial Ecological Lake Based on Water Quantity Objective

为研究如何长期保持人工生态湖水体清洁,以象湖为研究对象,应用MIKE 21水环境数值模拟软件,构建了象湖二维水动力和水质模型。通过对象湖生态工程进行模型概化,对湖区流场和水质进行研究,模拟计算了不同补水方式、换水方案下湖区流场变化及湖体水质演化过程,结果表明:在自然风条件下,湖区换水周期从西到东逐渐增加,在湖区东部,换水周期相近;在1 m^3/s的换水流量下,湖区西部换水周期小于22 d,湖区东部换水周期为22~27 d;在6—9月换水6次,即在夏秋季高温天气时保持1 m^3/s的换水流量可满足水质控制目标,若配套采用环湖湿地,夏秋季进行4次换水可达到水质管理目标。

In order to study how to keep the water body of artificial ecological lake clean and clear in the long term,the ecology project of Xianghu Lake was taken as a research object and,with the MIKE 21 numerical simulation software of water environment applied,the model of water power in two dimensions and water quality of the lake was constructed.Through model generalization of the ecological project of Xian ghu Lake and study on the flow field and water quality of the lake area,it simulated and calculated the changes of flow field and the evolution process of water quality under the different water replenishment modes and water exchange schemes.The outcomes show that in natural wind condition,the water exchange period gradually increases from west to east in the lake area which is similar in the eastern part.By 1 m3/s of the water exchange’s discharge,in the western part of the lake area is less than 22 days while the one in the eastern part is 22 days to 27 days.From June to September,six times of water exchanges are needed,that is,the goal of water quality control can be achieved by 1 m3/s for water exchange period in high temperature weather of summer and autumn.If the lake wetland is also used,the goal of water quality con trol can be obtained through four times of water exchange in summer and autumn.