洞庭湖水位变化对水质影响分析

长江中下游江湖关系的剧烈演变引起了洞庭湖水位的相应变化,并带来了显著的生态环境效应。为了揭示洞庭湖水位变化与水质变化的内在联系和特征,根据洞庭湖区典型水文站1995年-2010年历史水位与水质观测资料,从年内季节和年际时间尺度上,对洞庭湖水位变动情况及其对水质的影响进行了分析。结果表明,所选的洞庭湖区的典型水文站15年来水位总体呈现下降的趋势;在年际变化上,水质指标TN、高锰酸盐指数随着水位的降低而升高;年内季节变化上,TN含量表现出枯水期>平水期>丰水期的特征,而TP含量表现出相反的特性,随着丰水期水位的升高而含量也相对升高。总体上,洞庭湖水位变化与水质状况表现出较强的相关性。

Effects of Water Level Variation on Water Quality in Dongting Lake

The dramatic evolution of river-lake interactions in the middle and lower reaches of the Yangtze River has led to a corresponding change of water level in the Dongting Lake,which also resulted in the significantly ecological and environmental effects.In order to reveal the internal relationships and characteristics between the water level change and water quality change of the Dongting Lake,the effects of water level changes on the water quality in the Dongting Lake were analyzed from the intra-(seasonal) and inter-annual scales based on the monitoring data of water level and water quality at the typical hydrological stations in the Dongting Lake from 1995 to 2010.The results showed that:(1) The water levels at the typical hydrological stations have a decreasing trend;(2) In terms of the inter-annual variation,the contents of TN and permanganate index increase with the decreasing of water level;and(3) in terms of the annual(seasonal) variation,the concentration of TN is higher in the dry season than that in the normal season,which is higher than that in the wet season,whereas the concentration of TP has an opposite trend,which means that the TP concentration increases with the increasing of water level.On the whole,the change of water quality in the Dongting Lake has a strong relationship with the variation of water level.