洞庭湖区生态环境退化状况及其原因分析

洞庭湖居湖南省东北隅,长江荆江段南岸。湖泊形状呈近似“U”字形,岳阳站水位33.50 m时(黄海基面),湖长143.00 km,最大湖宽30.00 km,平均湖宽17.01 km,湖泊面积2625 km2;最大水深23.5 m,平均水深6.39 m,蓄水量167?08 m3。因入湖泥沙长期淤积、高洲围垦、并垸合流等自然因素和人类活动的共同影响,自清代末期以来,湖泊形态演变剧烈,湖盆抬高,入湖河流三角洲快速发育,湖面南移而缩小;现湖体已明显演变为西洞庭湖、南洞庭湖和东洞庭湖首尾相接三个部分,具有“高水湖相,低水河相”的典型特征。洞庭湖区不但是我国受洪水威胁最严重的地区之一,而且生态退化和环境问题也十分突出,一直受到国家的高度重视。文章在大量调查的基础上,对洞庭湖及其湖区的生态环境退化状况、产生原因和可能带来的负面影响等方面进行了初步分析。

Analysis of the situation and cause of ecological and environmental degeneration of the Dongting Lake

Dongting Lake is located in the north east of Hunan province and to the south bank of Jingjiang river. The lake presents the shape of "U", with the areas of 2625 km2, the longth of 143 km, the average width of 17.01 km (the maximum of 30 km), the average depth of 6.39 meters (the maximum of 23.5m), and the volume of storage of 1.671010 m3, as the level of water reaches 33.50 m in Yueyang.The lake has changed into 3 sections, i.e., west, south and east Dongting Lake with the feature of lakes and rivers. The shape of the lake also has evolved dramatically, the bottom of the lake has become high, delta has developed rapidly,and the surface of the lake has become small and moved towards the south, because of the mutual influences of nature and the humans including long-term silting, land exploiting and confluencing. The region of Dongting Lake, which not only is one of the areas that threatened by flood, but also faces the problems of serious degeneration of the ecology and the environment, is always paid great attention by the country, China. In this article, the situation and causes of the ecological and environmental degeneration of the region of Dongting Lake and the potential negative effects are analyzed based on a lot of investigations.