江库连通条件下珠海市饮用水源水质分布特征及水资源调配措施

Water quality distribution characteristics and water resources allocation measures of river-reservoir connected drinking water sources in Zhuhai City

  • 摘要: 珠海市河流型和水库型饮用水源的补给来源均主要来自西江,其中水库型水源主要通过西江泵站调水的方式进行蓄水。利用聚类分析和判别分析对水源水质时空分布特征进行了分析,讨论水期变化和水源位置等因素对水源水质的影响,并通过水力停留时间计算和相关性分析,初步探讨了水资源调度及水力停留时间对水源水质的影响。结果表明:珠海市水源水质可分为西江上游河流型水源、西江下游河流型水源和水库型水源3类;水库型水源中的总磷、粪大肠菌群、硫化物、硝酸盐浓度低于河流型水源,其中,水库型水源、河流型水源中的总磷浓度分别为0.01~0.04、0.04~0.12 mg/L,硝酸盐浓度分别为0.006~1、0.100~2 mg/L;上游河流型水源受咸潮上溯影响较小,下游河流型水源枯水期硫酸盐及氯化物浓度显著上升,但丰水期水质与上游河流型水源差异较小。基于上述分析结果,提出水资源调配措施:1)通过延长水库水力停留时间,包括提高库容量较大水库利用率,调整水库与泵站的连通方式等,以发挥水库型水源营养盐自净功能。2)枯水期可发挥上游河流型水源咸潮抵御的功能优势,保障水源盐度达标,丰水期可发挥下游河流型水源供水成本较低的优势,加大其水源取水比例。3)优先选取总磷、硝酸盐浓度较低(如总磷浓度达到湖库型水源Ⅲ类标准限值),且距离城区较近的泵站进行供水。通过上述措施的实施,提高水质因素在水资源调配中的作用,降低水资源调度对水源水质的冲击和水源水质超标风险。

     

    Abstract: The recharging sources of river and reservoir type of drinking water sources in Zhuhai City are mainly from Xijiang River, among which the water storage of reservoir type of water sources is mainly supplied by pumping stations from Xijiang River. Cluster analysis and discriminant analysis were used to analyze the characteristics of spatial and temporal distribution of water quality in drinking water sources, so as to discuss the influence of water season change and water sources location on water quality. Water retention time calculation and correlation analysis were used to preliminarily study the influence of water resources allocation and hydraulic retention time on water quality. The result shows that the source water quality in Zhuhai City could be divided into three categories: upstream river type, downstream river type and reservoir type. The concentrations of total phosphorus, fecal coliform, sulfide and nitrate in reservoir type of water sources were lower than those in river type of water sources. The total phosphorus concentrations in the reservoir and river types of water sources were 0.01-0.04 and 0.04-0.12 mg/L, respectively; and the nitrate concentrations were 0.006-1 and 0.100-2 mg/L, respectively. The river type of water sources in the upstream were less affected by the salt tide. The concentrations of sulfate and chloride of river type of water sources in the downstream increased significantly in the dry season, and the water quality of the water source of the downstream in the wet season was similar to that of the upstream. Based on the above analysis result, water resources allocation measures are proposed: Firstly, the self-purification function of reservoir type of drinking water sources could be utilized by extending the hydraulic retention time, including increasing the utilization rate of the reservoir with large capacity and adjusting the connection mode between reservoirs and pumping stations. Secondly, the salt tide resistance function of upstream river type of drinking water sources could be utilized to ensure water salinity meeting the standard in the dry season. Lower cost advantage of downstream river type of drinking water source could be utilized and the water utilization proportion could be increased in the wet season. Furthermore, the pumping stations with lower total phosphorus and nitrate concentrations (such as total phosphorus concentration reaching the standard limit value of type Ⅲ of lake-reservoir type water sources) and closer to the urban area were preferentially selected for water supply. Through the implementation of the above measures, the consideration of water quality factors in water resource allocation is improved, and the impact of water resource scheduling on water quality and the risk of water quality exceeding standard are reduced.

     

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