综合营养状态指数法评价鄞州区水库富营养化程度

Evaluation of Reservoir Eutrophication in Yinzhou District Based on Comprehensive Eutrophication State Index Method

采用综合营养状态指数法评价叶绿素a(Chl-a)、TN、TP、COD_(Mn)和透明度(SD)等参数的年均和月均变化,用于反映宁波市鄞州区6个水库的富营养程度;并根据各因子在综合营养状态指数中所占权重,对各因子进行比较。结果表明,鄞州区主要供水水库近5年一直处于中营养状态,综合营养状态指数在40左右波动,富营养化处于不稳定状态;鄞州区各水库的富营养化因子所占权重不同,主要影响因子不一,但TN因子是各水库富营养化的瓶颈;鄞州区水库富营养化波动呈显著的季节特征,春季和夏季富营养化程度形成高峰、秋季和冬季次之。

The comprehensive eutrophication state index method was adopted to evaluate yearly and monthly state of Chl-a, TN, TP, CODMn, SD and other parameters to describe the eutrophication of the six reservoirs in Yinzhou District. Each factor was compared according to the weights of various fac- tors in the comprehensive eutrophication state index. The results showed that： ① The main water supply reservoirs in Ningbo Yinzhou District were in nutritional status in nearly five years, and the comprehen- sive nutrition level fluctuated in 40, with eutrophication in an unstable state ; ②The weights of eutrophi- cation factors were different in reservoirs in Yinzhou District. The main factors that influence the reservoir were different, but the TN was the choke point of eutrophication of every reservoir; ③ Along with season- al changes, the eutrophication of the reservoirs varied obviously and formed a peak in spring and sum- mer, and autumn and winter took the second place.