Hongze Lake, previously known as Lake Hungtze or Hung-tse, is the fifth-largest freshwater lake in China. Although it is known to have existed from antiquity, it drastically increased in size during the Qing when the Yellow Riverthen still flowing south of Shandongmerged with the Huai. The increased sediment and flow combined to greatly expand the lake, swallowing the previous regional center of Sizhou and the Ming Zuling tombs. During the imperial and republican periods, the lake formed part of the border between Jiangsu and Anhui provinces but since 1955 the previous borders have been shifted to place it entirely under Jiangsu's administration. It is now encompassed by the counties of Sihong and Siyang in Suqian Prefecture and Xuyi and Hongze in Huai'an Prefecture. Since the establishment of the People's Republic of China, the lake has generally decreased in size as more of its inflow has been diverted for irrigation. Geography Hongze Lake reaches an area of about 3 million mu when its depth reaches , making it the second-largest freshwater lake in Jiangsu and the fourth- or fifth-largest in the country, behind lakes Poyang, Dongting, Tai, and Hulun. Hongze Lake's meandering shoreline usually runs around . History The area that now forms Hongze Lake was an inlet of the East China Sea about 2 million year ago before being closed in by sediment from the Huai and other nearby rivers. In Chinese antiquity, the area formed a number of shallow lakes collectively known as Fuling. Other nearby lakes at the time that later merged into Hongze were Nidun and Wanjia. Under the Han, Fulin was renamed Pofu Pond. Under the Sui, this was connected to other waterways north and south to create the Grand Canal. During an inspection tour in 616, Emperor Yang renamed Pofu Hongze in his delight at the rain that greeted his arrival there, the rest of the countryside having suffered a drought. When it further expanded under the Tang, it became known as Hongze Lake. A massive flood of the Yellow River redirected it south of Shandong in 1128 or 1194, following the course of the Si to join the Huai below Huaiyin. The silt from the Yellow River began to obstruct the flow of the Huai and started to expand Hongze still farther, ultimately quadrupling its original size. During this period, it became an important fishery and center of irrigated cropland. It still forms the