Located in the upper and middle reaches of major rivers in Northeast China, Jilin Province serves as the source of a number of rivers. The volcanic cone around Tianchi Lake of Changbai Mountain, known as the Source of Three Rivers, is the birthplace of the Songhua River, Yalu River and Tumen River. Rivers and lakes cover an area of 265,500 hectares of the province. 1648 rivers with an area of more than 20 square kilometers belong to the following five river systems respectively, including Songhua River, Liaohe River, Yalu River, Tumen River and Suifen River. A total of 1397 lakes with water surface over 100 mu (0.067 square kilometers) fall into three major categories, i.e. crater lakes, fluvial lakes and inland lakes. With a much denser network of rivers, the eastern mountainous areas have a large surface runoff. The case reverses when it comes to the underground runoff, which is more abundant in western plain areas. 98% of the hydropower resources are distributed in the eastern mountainous areas. 9 large reservoirs, 94 medium reservoirs and 515 small reservoirs have been built in the province. Water projects such as diversion of water from Nenjiang River to Baicheng City and Hadashan water-control project have been put into operation.