层次分析方差赋权的物元模型在河流退化评价中的应用

Application of the matter element model for hierarchical variance analysis and the standard variance method to the river degradation assessment

构建了以河流地貌、水质水文、生物、功能特征为要素的河流退化评价指标体系,运用主观性层次分析和客观性方差赋权相结合的方法确定各指标权重,并结合物元模型提出了一种河流退化评价方法。以河南省沙颍河流域为例,对沙颍河、沙河、颍河及贾鲁河2013年平水期河流退化状况进行了评价。结果表明,随着城市化、工业化的发展,河流退化不仅局限于水质,河流生物特征、功能特征均出现了较严重的退化状况,尤其是河流功能特征要素。其中,40.9%的评价河流断面属中度退化,13.6%属重度退化,其他评价断面均属于极度退化。与单个层次分析法赋权及熵权赋权方法相比,层次分析方差赋权的物元模型既克服了赋权过于主观,又充分发挥了评价数据本身的重要性,更符合实际情况,且计算简单,结合物元模型,解决了评价指标不相容的问题,丰富了河流退化评价的方法。

The paper is aimed at establishing a comprehensive assessment system for the river degradation management needs by taking the degrading degrees of the following rivers in Henan,such as Shaying River,Sha River,Ying River and Jialu River as a case study sample during the normal-water level period in 2013. In this paper,we have also chosen such factors,as the river physiognomy（ 2 indexes）,the water quality and hydrology（ 4 indexes）,the living creatures（ 5 indexes） and the functional features（ 2 indexes） to assess the extent of the river degradation degrees,to verify the causative factors,and then to restore the factors-induced change and damage to river ecosystem,based on the influential factors on the structure and function of the river ecosystem and its degradation. For the research purpose,we have jointly applied the subjective analytic hierarchy process（ AHP） and the objective standard variance method to identify and determine the weights of all the indexes involved for the eventual assessment of the river degradation degrees via the matter-element model. Taking Shaying River basin,for example,we have investigated through the combined method above,and examined the degradation extent of the river during the normal-water maintenance period in 2013,finding that the river degradations should not only be attributed to the pollution of water quality,but also to the deterioration caused by the biological and functional factors,particularly to the latter. Of all the aforementioned influential factors,the moderate and severe degradation degrees can account for 40. 9% and 13. 6%,respectively,with the remaining indexes belonging to the extreme degrees. According to the degradation degrees,Jialu River stands for the highest. Though the leading degradation indexes may noticeably vary among the river sections under study,we have also made an exploration of the water resources for the declining order in terms of percentage of the leading indexes,such as the rate of the river water exploitation,the comprehensive pollution indexes of the water sediment and flowing speed so as to determine the remediation liability of the river ecosystem on reliance of the leading degradation indexes. Thus,as compared with the individual assessment via the AHP or entropy weight,the comprehensive method we have adopted can not only get rid of subjectivity in weight rationing process,but also can fully attribute the importance of the chosen factors,thus assuring more availability for the actual assessment situation. Moreover,the method we have chosen proves to be simple in calculation and incompatible among the indexes,which tend to be a powerful method for river water degradation assessment.