三峡水库夏季次级河流库湾营养状态及营养盐输出

2003年6月三峡水库成库后,由于水体流速减缓,部分次级河流库湾发生了不同程度的富营养化现象。2004年7月,对受三峡水库蓄水影响的12条次级河流库湾夏季水体营养化程度进行了调查。结果表明:pH值7.17~8.89;DO含量2.20~10.10 mg/L;透明度0.1~1.0 m;CODMn1.60~9.79 mg/L;TN0.72~5.27 mg/L;TP0.013~0.369 mg/L;叶绿素a 1.54~20.00 mg/m3。三峡水库次级河流库湾水体夏季营养程度较高,根据综合营养状态指数法评价的结果表明,各条次级河流的综合营养状态指数39.2~69.2,其中8条河流达富营养化水平,4条河中营养,无贫营养。12条次级河流CODMn、TN、TP输出负荷总量分别为:1773.6、1153.1和61.25 g/s。随着三峡水库蓄水水位的提高,受蓄水影响的次级河流增多,库湾的长度及面积加大,三峡库区次级河流库湾水体富营养化现象可能会更加严重。

Trophic States and Nutrient Output of Tributaries Bay of Three Gorges Reservoir in Summer

After the Three Gorges Reservoir impoundment in June 2003, the phenomenon of eutrophication were found in some tributaries bay due to the slow flow velocity. Water quality of tributaries in Three Gorges Reservoir were investigated in July 2004. The pH, DO, SD, CODMn, TN, TP and Chla ranged from 7.17 -8.89, 2.20 -10.10 mg/L,0.1 -1.0 m,1.60- 9.79 mg/L, 0.72 -5.27 mg/L,0.013 -0.369 mg/L, 1.54 - 20.00 mg/m^3,respectively. Trophie states degree of tributaries bay was serious in summer. With the method of the integrated nutrition state index, the trophie states degree of tributaries was assessed. In all of the tributaries studied, 8 trbutaries were eutropher and 4 were mesotropher, respectively. No The tributary was oligotropher. The nutrient fluxes load of CODMn,TN and TP were 1 773.6,1 153.1 and 61.25 g/s, respectively in one year. With the water level increased, mere and more tributaries would be affected by Three Gorges Reservoir. With the length and area of tributaries bay increased, the eutrophication trend of tributaries estuaries would be more serious.