Qiandao Lake, also known as the Xin'an River Reservoir, serves as the water body for the Xin'an River Hydropower Station. Located within Chun'an County and Jiande City—both in the southwest of Hangzhou, Zhejiang Province, People's Republic of China—the reservoir is primarily designed for power generation, while also supporting flood control, irrigation, fisheries, navigation, and tourism. It functions as a large-scale, multi-year regulating reservoir. Created in 1959 following the construction of a dam at Tongguan Gorge in Jiande, the reservoir covers an area of 567.40 square kilometers. Mountain peaks that remained above water after the reservoir was filled became islands; when the water level is maintained at an elevation of 108 meters (relative to the Yellow Sea datum), there are 1,078 islands, each measuring at least 2,500 square meters—a feature that earned the reservoir the name "Qiandao Lake" (literally "Thousand-Island Lake").
The entire lake area is divided into five distinct geographical zones—central, southeastern, northwestern, southwestern, and northeastern—with the central and southeastern sections having been developed into commercial tourism zones.