“拉开档次”法的改进及其在河流生态健康评价中的应用

Improvement of “scatter degree” method and its application in evaluating river ecosystem health

针对"拉开档次"法在进行综合评价过程中不能较好反映评价者主观信息的缺点,并考虑到影响河流生态系统健康的因素具有多层次、不确定和属性复杂等特点,对"拉开档次"法进行改进,并运用改进的"拉开档次"法对流经北京和天津的北运河上、中、下游各区段进行生态健康综合评价.结果表明,北运河上、中、下游各区段生态系统健康评价值分别为0.539、0.521、0.546,生态状况均处于亚健康状态;河流水环境状况对北运河生态系统健康影响程度最大.运用改进后的"拉开档次"法进行河流生态系统健康评价,既兼顾了评价者的主观判断,又包含了数据本身的客观信息,评价过程透明,评价结果科学、合理、客观、可靠,可为河流综合治理提供技术支持和基础依据.

＂Scatter degree＂ method is generally blamed for not capable of reflecting the subjective information of evaluator in comprehensive evaluation and for the complexity,uncertainty,and variety of the factors affecting river ecosystem health.In this paper,the ＂scatter degree＂ method was improved and applied to comprehensively evaluate the ecosystem health status of the upstream,midstream,and downstream of Beiyunhe River which flowed through Beijing and Tianjing.The ecosystem health value of upstream,midstream,and downstream was evaluated as 0.539,0.521 and 0.546,respectively,indicating that these streams were in sub-health condition.The environmental status of flowing water was the most important factor affecting the River＇s ecosystem health.With the application of the improved method to evaluate river ecosystem health,both the evaluator＇s subjective judgment and the data＇s objective information could be included,the evaluation process was transparent,and the evaluation results were scientific,reasonable,objective,and reliable,suggesting that this method could be served as a technical support and a basis for the comprehensive treatment of rivers.