改进的综合标识指数法在水质评价中的应用

APPLICATION OF IMPROVED COMPREHENSIVE INDEX METHOD IN WATER ENVIRONMENTAL QUALITY ASSESSMENT

针对综合标识指数法在水质评价中未考虑指标权重的情况,采用熵权与层次分析组合赋权的方法对各评价指标权重赋值。将改进的综合标识指数法应用于西充县境内西充河流域水质评价,结果表明:流域综合水质全年有67%的时间劣于Ⅲ类水质标准,其中虹溪河水质污染状况比龙滩河更为严重;水质状况随枯、丰水期的变化而表现出规律性,丰水期水质稍好于枯水期;各评价指标权重系数与实际监测数据相一致,说明该赋权方法具有合理性,且确定了总氮(TN)与高锰酸盐指数为主要污染因子;改进后的综合标识指数(WQI)因考虑主要污染因子的贡献率而略有升高,符合实际情况且使水质评价结果更加准确。

As the comprehensive water quality identification index method fails to objectively take into account index weights in water quality evaluation,the analytic hierarchy process( AHP) method and entropy-weight method were adopted to determine combination weights for all indices. The improved comprehensive water quality identification index method was used to evaluate the water quality of Xichong River basin existed in Xichong County. The evaluation results show that 67% of the year for water environment quality of river basin is inferior to the class Ⅲ water quality standard,and the water pollution in Hong Xi River Basin was more serious than the Longtan River; water quality shows regular change with the dry season and wet season,the water quality in wet season was slightly better than it in dry season; The weight coefficient of each evaluation index is consistent with the actual monitoring data,which shows that the weighting method is reasonable and confirmed the total nitrogen( TN)and permanganate index are the main pollutants; The improved water quality identification index( WQI) are all higher than the un-improved because of considering the contribution rate of main pollution factor and the result of water quality assessment is more realistic and accurate.