１、流域生态系统的概况 我国是世界上陆地水域面积最大的国家之一，江河、湖泊、水库众多。大小河流总长度达４２万ｋｍ。流域面积在１万ｈｍ２以上的河流就有５００００多条；湖泊面积在１００ｈｍ２以上的有２８４８个，总面积达８００万ｈｍ２以上。 １．１河流 我国的河流 1. Overview of Basin Ecosystem China is one of the countries with the largest land area in the world, with many rivers, lakes and reservoirs. The total length of rivers is 420,000 km. There are more than 50,000 river basins with river basins above 10,000 hm2; and 2,848 lakes with more than 100 hm2, with a total area of ​​more than 8 million hm2. 1.1 The river Our country’s river