河流综合水质评价方法比较研究

COMPARATIVE STUDY ON TYPICAL RIVER COMPREHENSIVE WATER QUALITY ASSESSMENT METHODS

为探讨综合水质评价结论的科学合理性，对典型的7种河流综合水质评价方法，包括单因子评价法、污染指数法、模糊评价法、灰色系统评价法、层次分析法、人工神经网络法、水质标识指数法，在归类分析其特性的基础上，针对代表性的评价样本，进行了综合水质评价比较研究。主要结论为：①单因子评价法以最差水质指标所属类别作为综合水质类别，评价结论表现为过保护；②污染指数法能够直观判断综合水质是否达到功能区目标，但是不能判断综合水质类别；③对模糊数学法、灰色系统评价法、层次分析法、BP人工神经网络法和水质标识指数法等5种典型评价方法，当综合水质为Ⅰ～Ⅴ类水情形时，这几种方法评价结论基本一致，证明这5种典型评价方法对Ⅰ～Ⅴ类水的评价结论具有科学合理性；④当综合水质为劣Ⅴ类水时，模糊数学法、灰色系统评价法、层次分析法、BP人工神经网络法的评价结论偏保守，而水质标识指数法鳃决了劣Ⅴ类水质的连续性描述问题，能够对劣Ⅴ类水进行科学合理评价，并对Ⅰ～Ⅴ类水、劣Ⅴ类水不黑臭、劣Ⅴ类水黑臭进行全面、科学合理的定性与定量评价。

Based on representative samples,a comparative study was carried out for seven typical comprehensive water quality assessment methods including single factor assessment method, pollution index method, fuzzy method, grey system method, analytic hierarchy process method, artificial neural network method, water quality identification index method. The study conclusions are： （1） The single factor assessment method selects the worst water quality class of water quality indices to be the comprehensive water quality class,and gives a over-emphasizing result. （2） The pollution index method can qualitatively judge whether the comprehensive water quality meets the specified water function objective,but it can＇t judge comprehen- sive water quality class. （3） The other five methods including fuzzy method,grey system method,analytic hierarchy process method, artificial neural network method and water quality identification index method present the nearly identical comprehensive water quality assessment results for the samples of comprehensive water quality class Ⅰ～Ⅴ ,which prove the rationality of five methods for comprehensive water quality class Ⅰ～Ⅴ. （4） For the comprehensive water quality of inferior class Ⅴ ,the fuzzy method,grey system method ,analytic hierarchy process method, artificial neural network method underestimate the comprehensive water quality,by comparison,the water quality identification index method can give a scientific conclusion due to the consecutive depiction of water quality inferior class Ⅴ. Further,a qualitative and quantitative assessment of class Ⅰ～Ⅴ,inferior class Ⅴ while no blackness and stink,inferior class Ⅴ while blackness and stink, is scientifically and completely achieved based on water quality identification index method.