Hangzhou West Lake is located in Hangzhou City, Zhejiang Province, west of Hangzhou city, formerly known as martial arts water, Qiantang Lake, West Lake, West Lake, said before the Song Dynasty. Surface of the lake north to south and 3.3 kilometers from east to west 2.8 kilometers wide, the original surface area of 5.64 square kilometers, including the lake island of 6.3 square kilometers, Lake circumference of 15 kilometers. An average depth of 1.21 meters, maximum depth of 6.52 meters, the most shallow at less than 1 m, the most muddy at 5 meters. Today, accompanied by "the West Lake West" expanded to 6.5 square kilometers, basically reached 300 years ago, the West Lake area. Su Causeway and Bai Causeway into the lake where Lake, outside the Lake, Yue Lake, Xili Lake and a small part of South Lake 5. West Lake and the Qiantang River to communicate after the introduction of Qiantang River water each day about 30 million cubic meters of water from West Lake, a year into a monthly one-for-one exchange, transparency, less than 60 cm from upgraded to 120 cm. Of the original ancient bay, after blocking the formation of the Qiantang River sediment deposition.