Qiandao Lake (), a human-made, freshwater lake located in Chun'an County, Hangzhou, Zhejiang Province, China, was formed after the completion of the Xin'an River hydroelectric station in 1959. Geography 1,078 large islands dot the lake and a few thousand smaller ones are scattered across it. Over 90% of the land area is forested. The islands in the lake 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 covers an area of and has a storage capacity of . The islands in the lake cover about . The trend of Qiandao Lake's transformation from mid mesotrophic to mesotrophic, the polluting elements are heavy metals, nitrogen, phosphorus and organic matter, cages and cruise ships; (up to 10 meters underwater) the temperature changes greatly, with an average of 28.2 ℃-24.4 ℃, and the water temperature is mostly maintained at a relatively high temperature, called the warm water layer, which is greatly affected by floods. About 30 meters up and down there is a sudden change of water temperature. This layer can also be called thermocline. Spanning an area that nearly matches the size of Singapore and renown for having clear waters, Qiandao Lake hosts a major fishery and aquaculture industry. There are 83 species of fish in 13 families, including bighead carp, silver carp, grass carp, as well as precious fish species such as tuna, mandarin fish, and eel, with an annual output of more than 3,000 tons. It has also developed an artificial breeding industry, that mainly breeds carp, bream and tilapia, with an annual output of nearly 900,000 tons. Due to its still waters, the lake is stocked with 30,000 sturgeons, a species that is native to Russia and Central Asia, which are bred to produce caviar for the Kaluga Queen label. The stillness of the waters helps the sturgeons to not have to swim against water currents and consequently be fattier, which allows its roe to be tastier and richer. History Xin'an River Dam The valley was flooded in 1959 to create the lake for the Xin'an River Dam project. The dam that created the lake is located at and is tall with a crest length of . Xin'an Dam was the first dam constructed in China with a height greater than and its power plant has an installed capacity of 845 MW.