基于水量-水质模型的星海湖生态补水量研究

Study on the ecological water supply of Xinghai Lake based on water quantity and quality model

【目的】探明星海湖主要污染物指标,并研究分析不同水质目标下的生态补水量,为改善星海湖水环境质量提供参考.【方法】于2017年各月采集水样检测水环境指标含量,采用主成分分析法确定影响星海湖水质的主要水环境因素,构建水量-水质模型,并分析计算星海湖不同水质标准下的生态补水量.【结果】星海湖水环境主要影响因素为总氮(TN)、总磷(TP)、高锰酸盐指数(COD Mn)、重铬酸盐指数(COD Cr).星海湖水质保持现状不再恶化所需补水量由污染物指标COD Cr决定;星海湖水质达到地表水水质标准中规定Ⅳ类时,所需补水量由污染物指标COD Mn和COD Cr共同决定;星海湖水质达到地表水水质标准中规定Ⅲ类水时,所需补水量由污染物指标COD Cr决定.星海湖水质保持现状、达到Ⅳ类、Ⅲ类水标准时,其所需补水量分别为7420万m 3、12496万m 3、15244万m 3.【结论】星海湖水环境主要污染物指标为TN、TP、COD Mn、COD Cr,大量N、P元素及有机物进入星海湖中造成水体营养盐超标和有机污染;不同污染物指标需净化稀释的补水量差异较大,与N、P营养盐超标净化稀释所需水量相比,有机污染物的净化稀释是造成星海湖补水量大的主要原因,稀释补水应以降低水体有机物含量为主.

【Objective】To explore the main pollutant indicators of Xinghai Lake and analyze the amount of ecological water replenishment under different water quality targets,as well as to provide a reference for improving the water environmental quality of Xinghai Lake.【Method】Water samples were collected in each month to detect the water environmental indexes.The principal component analysis method was used to determine the main water environmental indexes affecting the water quality.A water quantity and quality model was built up to analyze and calculate the ecological water supply under different water quality standards.【Result】The main influencing factors on the water environment of Xinghai Lake were total nitrogen(TN),total phosphorus(TP),permanganate index(COD Mn),and dichromate index(COD Cr).The required amount of supplementary water was determined by COD Cr if the lake water quality was maintained at current status and not be worse.It was by both pollutant indicator COD Mn and COD Cr if the lake water quality was maintained at ClassⅣof surface water quality standard.And it was determined by COD Cr if the lake water quality was maintained at Class III.Their relevant amounts of supplementary water were 1.2496×108 m 3,7.42×107 m 3 and 1.5244×108 m 3 respectively.【Conclusion】The main pollutants in the water environment of Xinghai Lake are TN,TP,COD Mn,and COD Cr.A large amount of N,P and organic substances enter result in the nutrients in water body exceeding the standard and organic pollution.The required supplementary water amount varies greatly for purifying and diluting different pollutants.Compared with N and P,the purification and dilution of organic pollutants need more water.