Qiandao Lake (Chinese: 千島湖, lit. Thousand Island Lake), a man-made lake located in Chun'an County, Zhejiang, China, formed after the completion of the Xin'an River hydroelectric station. 1,078 large islands dot the lake and a few thousand smaller ones are scattered across it. The lake covers an area of 573 km² and has a storage capacity of 17.8 km³. The islands in the lake cover about 86 km².
Qiandao Lake, known for its clear, and sometimes drinkable water, is used to produce the renowned Nongfu Spring brand of mineral water. It is also home to lush forests (over 90%), and exotic islands. Its more popular attractions include Bird Island, Snake Island, Monkey Island, Lock Island (featuring supposedly the world's biggest lock), and the Island to Remind You of Your Childhood.
The lake gives Zhejiang an important tourist attraction. Newer housing developments have sprung up since the late 1990s at a reasonable cost to buyers looking for lakeside residences.
The dam creating the lake is located at 29°29′01″N 119°12′48″E / 29.48361°N 119.21333°E / 29.48361; 119.21333 (Xin'an Dam) and is 105 m (344 ft) tall with a crest length of 466.5 m (1,531 ft). Xin'an Dam was the first dam constructed in China with a height greater than 100 m (328 ft) and its power plant has an installed capacity of 845 MW.
At the foot of the Wu Shi mountain (Five Lion Mountain) lays an ancient city known as Shi Cheng (Lions City), built in Dong Han period (25 - 200), first was set up as county in 208, it was named "Lion City" because of the Five Lion Mountain that sits just behind the city. The city remains undisturbed from the surface at a depth of 26-40m, Big Blue dive operator based in Shanghai, runs weekend trips twice a month throughout the year to the city and has started to uncover parts of the lost city.
In 1994, three bandits raided a boat and set it on fire, killing all 32 passengers on board, mainly Taiwanese tourists, in a notorious event named the Qiandao Lake Incident.
In 2007, a Chinese-Italian consortium started to plan the construction of a prototype of an archimedes bridge in the lake, spanning 100 m, as a proof-of-concept for larger bridges.