四川省位于东经97°21′～108°12′,北纬26°03′～34°19′之间,面积56.76万平方公里。有大、中、小河流1,300多条,大水系有金沙江、雅砻江、大渡河、青衣江、岷江、沱江、涪江、嘉陵江、渠江、乌江(下游部份)、长江(上游干流)等(参见图1)。海拔高程自7556.0米(贡嘎山)降至100.0米左右(万县附近),有高原、山区、丘陵、平原等各类地形。有高 Sichuan Province is located between 97 ° 21 ’~ 108 ° 12’ east longitude and 26 ° 03 ’~ 34 ° 19’ north latitude with an area of ​​567,600 km2. There are over 1,300 large, medium and small rivers. There are Jinsha River, Yalong River, Dadu River, Qingyi River, Minjiang River, Tuojiang River, Fujiang River, Jialing River, Qujiang River and Wujiang River (the downstream part), the Yangtze River ), Etc. (see Figure 1). Elevation elevation from 7556.0 meters (Gongga Mountain) down to 100.0 meters (around Wanxian), a plateau, mountains, hills, plains and other terrain. High