杭州市新取水口水质论证

Argumentation on Water Quality of New Water Intake in Hangzhou City

杭州市为抵御咸潮,满足日益增长的用水需求,计划将自来水取水口由珊瑚沙上移至里山位置。在规划期里山取水口的水质能否达到饮用水水质标准是公众关心的问题。在分析里山河段现状水质的基础上,借助Mike21软件,进行了钱塘江多站位水文及水质的验证,计算了规划期里山取水口附近的水质情况,并通过改变上游径流量、上游来水水质、下游潮汐条件、污染负荷控制情况对里山取水口的水质影响作敏感性分析,从而论证在里山位置设置取水口的合理性。通过计算分析表明,在规划期的排污条件下,上游枯水流量遭遇下游小潮时,里山河段的水质指标CODMn接近二类水体临界值,为确保饮用水的质量,需削减城镇污染负荷的排放。上游径流量、上游来水水质、下游潮汐条件、污染负荷的改变对里山取水口水质的影响敏感。

In order to resist salt water intrusion and meet the demand of increasing water consumption,Hangzhou City government plans to move the water intake from Shanhusha to upstream a site called Lishan.Whether the water quality of new water intake can reach quality standard has become the focus of public concerns.Firstly,this paper analyzed present water quality;secondly,field data of hydrology and water quality of several stations in Qiantang River were validated with the 2-D mathematical model Mike21.Then concentration in programming pollution load was calculated.Furthermore,on the basis of analyzing the influence factors on water quality such as upstream runoff amount and upstream water quality,and downstream tide range and pollution load,the rationality of water intake at Lishan site was evaluated.From these studies,when upstream low flow meets downstream neap tide,the concentration of water quality index CODMn is close to national second-class seawater standard（GB 3097-1997）.In order to insure water quality,pollution load should be reduced.The factors influencing water quality,such as upstream runoff amount and upstream water quality,and downstream tide range and pollution load,significantly effect water quality.