The water of the ancient canal in Suzhou comes from Taihu Lake and the Beijing-Hangzhou Grand Canal, and it is also integrated into the Yangtze River and the sea. Wu Zixuan opened the Lijiang River to introduce the Taihu Lake into the city, and the Grand Canal continuously injects the Yangtze River water. Many lakes in the suburbs also play an important role in water storage and regulation of the ancient city's water system.