三峡水库运行下荆南三口地区水环境承载力研究

Research on water environment carrying capacity of Three Diversions of Jingjiang River under operation of Three Gorges Reservoir

结合层次分析法和"模加和"法,分析了荆南三口地区在三峡水库运行前后的水环境承载力变化情况。结果表明:(1)三峡水库运行前,荆南三口地区的水环境承载力取值在0.24~0.36之间,属弱可承载等级,承载状态极为脆弱。空间上,华容的承载水平最高,在0.30以上;南县最低,小于0.29。(2)三峡水库运行后,华容、安乡、南县的水环境承载力值分别由2003年的0.32、0.38、0.27增至2014年的0.42、0.40、0.40。2007年前,安乡的水环境承载力高于华容和南县,地区间差异较大。2007年以后华容的承载水平略具优势,随着南县承载水平的提高,各分区间的差距缩小。(3)与三峡水库运行前的水环境承载力相比,荆南三口地区三县的承载水平均有所提升:华容县由0.32增至0.42,安乡由0.24增至0.40,南县由0.26增至0.40,但并无大的改善,水环境仍处于脆弱状态。(4)三峡水库运行下,荆南三口水沙量大幅下降,成为限制三口地区水环境承载力提升的关键要素。

Combining the method of Analytic Hierachy Process with “ mode and sum”,this study analyzed thechange of the water environment carrying capacity （ WECC ） of the Three Diversions of the Jingjiang River after the operation of the Three Gorges Reservoir （ TGR） . The results show that ： （ 1 ） before the operation of the TGR, the WECC of the Three Diversions of the Jingjiang River was between 0. 24-0. 36, which was in a weak level, and the carrying capacity was extremely fragile. In the space domain, the carrying level of Huarong was the highest, over 0. 30. The lowest was in Nanxian, less than 0. 29. （2 ） after the running of the TGR, the WECC of Huarong, Anxiang, Nanxian were increased respectively from 0. 32, 0. 38, 0. 27 in 2003 to 0. 42, 0. 40, 0. 40 in 2014. Before 2007, the WECC of Anxiang was higher than Huarong and Nanxian with considerable discrepancies between regions. After 2007, the carrying level of Huarong was at a slight advantage. With the increase of Nanxian’s WECC, the gap between various partitions was narrowed. （3） Compared with the WECC prior to operation of the TGR, the carrying level of each partition in the Three diversions of the Jingjiang River has been enhanced. The WECC of Huarong, Anxiang, Nanxian was increased respectively from 0. 32 to 0. 42, 0. 24 to 0. 40, 0. 26 to0. 40, but had no big improvement, the water environment was still in a fragile state. （4） Under the operation of the TGR, the significant decline of water and sediment in the Three Diversions of the Jingjiang River has become the key factor of restricting the enhancing of the WECC in the Three Diversions of the Jingjiang River.