三峡水库蓄水初期水生态环境特征分析

以2003年10月和2004年4月的两次现场调查数据为基础，分析三峡水库蓄水初期的水生态环境特征。结果表明，蓄水初期水库水体交换能力减弱，水库有机污染甚微，但水体TN、TP浓度偏高，水库整体处于中营养状态；根据水生态环境特征的差异性，水库水域可划分为3种类型区，即坝前水域、库区干流水域以及库区支流洄水河段。对主要影响因素进行分析，发现流速、营养盐含量及水温是影响水生态环境特征的主要因素，而由于各类型区的TP、TN等营养盐含量均较高，水温及流速已成为三峡水库水生态环境特征的控制性因子。探讨3类不同水域的富营养化敏感性，表明坝前水域及库区支流洄水河段是库区未来富营养化的敏感水域。

ANALYSIS OF AQUATIC ENVIRONMENTAL CHARACTERS IN THREE GORGES RESERVOIR OF CHINA AT EARLY RESERVING STAGE

Based on the preliminary investigation in Three Gorges Reservoir(TGR) from 12~th to 17~th of Oct.2003 and 17~th to 21~th of Apr.2004,this paper studied the aquatic environmental characters at early reserving stage of TGR.The results showed that the exchanging capacity of water body is weakened,organic pollution is relatively light,the concentrations of TN and TP are both quite high which met well enough to algae bloom in TGR and the integrative trophic state of reservoir is medium.According to the variation of the aquatic environmental characters,the water body of TGR could be divided into three kinds of reaches,namely the water fields before the dam,the mainstream reach in the middle reservoir,and the tributary reaches of reservoir.In account of the high concentrations of TP and TN,the authors justified that both water temperature and water velocity are the main causal factors in influencing the characters of river reaches in all 3 aspects.Considering the sensitivity of eutrophication of 3 different reaches,the authors found evidently that it is sensitive in both the water fields before the dam and the tributary reaches of reservoir,but relatively low sensitive in the mainstream reach in the middle reservoir because of the relatively high water velocity.