一、趋势、危害 洞庭湖为“吞吐型”淡水湖,纳湘、资、沅、澧四水及湖滨诸山河流,并吞吐长江分流。湖区位于荆江河南面,地理位置为北纬28°39′20″至30°14′18″,东经111°42′44″至113°39′45″之间,总面积18780平方公里,其中湖泊面积当城陵矶水位达33.5米时为2540平方公里(1980年)。各河流携带的泥沙倾泄入湖,平均每年淤积于湖内1.07亿立方米,使洞庭湖出现明显的淤积趋势。泥沙对于洞庭湖淤积主要表现在:(一)使湖床抬高。如果按1977年洞庭湖的2740平方公 First, the trend of endangering Dongting Lake as a “throughput type” fresh water lake, Nathan, capital, Yuan, four water and lake rivers and mountains, and throughput of the Yangtze River diversion. Located in the south of Jingjiang River, the lake locates between 28 ° 39’20 “and 30 ° 14’18” north latitude and 111 ° 42’44 “east longitude to 113 ° 39’45” east longitude with a total area of ​​18,780 km2, of which the lake area When the water level of Chenglingji up to 33.5 meters when 2540 square kilometers (1980). Sediment transported by rivers into the lake dumping, the average annual deposition of 107 million cubic meters in the lake, so that the apparent deposition of Dongting Lake trend. Sediment sedimentation Dongting Lake mainly manifested in: (a) the lake bed elevation. If by 1977, Dongting Lake 2740 square kilometers