模糊数学在香溪河库湾富营养化评价中的应用

三峡水库蓄水后,部分支流库湾水体富营养化严重。以香溪河库湾为例,采用模糊数学评价法,通过引入隶属度的概念,对该库湾2010年全年不同断面水质进行富营养化评价,同时与综合营养状态指数评价法比较。结果表明:2种方法结果存在一定差异,但均反映了2010年香溪河库湾处于中营养化至重度富营养化,春夏季富营养化情势较其他季节严重,库湾上游处于中度富营养化,4月上游甚至为重度富营养化,下游处于轻度富营养化;秋冬季库湾营养状态分布较均匀,为中营养和轻度富营养化。该结果与实地观测结果相符。由此可见,模糊数学评价法较好的反映水质级别的模糊性与连续性,以及各因子共同作用下的水质状况,可在三峡水库支流库湾富营养化评价中得到应用。

Fuzzy Mathematics for Evaluation of Eutrophication in Xiangxi Bay

Since the impoundment of Three Gorges Reservoir,different extents of eutrophication have occurred in parts of tributaries.Taking Xiangxi Bay(XXB) as an example,fuzzy mathematics was used to evaluate the eutrophic status of different sections in XXB in 2010 by introducing the concept of membership.Results of fuzzy mathematics evaluation were compared with those of comprehensive nutrition state index method.Results showed that although there are some differences between the two methods,both of them demonstrate the mesotrophic to hyper-eutrophic state of XXB in spring and summer.The eutrophic state is more serious in spring and summer than that in other seasons.Medium eutrophication has occurred in the upstream of XXB,wherein even as hyper-eutrophic state in April,whereas mild eutrophication has emerged in the downstream.In addition,mesotrophic and mild eutrophication have occurred in autumn and winter with the uniform distribution of nutrients in XXB.Results are consistent with the field observations.The fuzzy mathematics evaluation method could reflect the continuity and ambiguity of the levels of water quality,and reveal water condition affected by all factors.As a consequence,it could be used to evaluate eutrophication in tributaries of Three Gorges Reservoir.