History of Qiandaohu Lake
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 29°29′01″N 119°12′48″E 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.
Submerged city of Shi Cheng
Submerged in the lake, at the foot of Wu Shi Mountain (五狮山, “Five Lion Mountain”), lies an ancient city known as Shi Cheng (狮城, “Lion City”). It was built during the Eastern Han Dynasty (AD 25–200) and was first set up as a county in AD 208. The city acquired its name from nearby Wu Shi (Five Lion) Mountain, which is now known as Wu Shi Island since it too became partially submerged by the reservoir. At present Shi Cheng remains well-preserved and undisturbed at a depth of 26–40 m (85–131 ft).
Besides the city of Shi Cheng many other historic sites have been confirmed beneath the water.
Qiandao Lake incident
In 1994, in an event since named the Qiandao Lake Incident, three hijackers boarded a boat full of tourists and set it on fire, killing all 32 passengers on board. The passengers were mainly tourists from Taiwan.
In 1998, a Chinese-Italian consortium began planning the construction of a prototype of a submerged floating tunnel (also known as an Archimedes bridge), and decided in 2005 to build it across Quiandao Lake. The bridge, the first in the world of its kind, is expected to span 100 m (330 ft), as a proof of concept for larger bridges.
Source From: https://en.wikipedia.org/wiki/Qiandao_Lake#History