Water Systems and the Watershed Divide of Lishui

Survey

The watercourses of Lishui District fall into three catchments by area (district government, geographical position page): the Qinhuai basin, 464.82 sq km; the Shijiu Lake basin, 599.39 sq km; and 2.73 sq km of hill country in the south-east corner, the only part belonging to the western Taihu region. These three are the values used in the basin filter on this site's list pages. The same page records that the divide between the two systems runs east to west across the middle of the district, that northern water flows to the Qinhuai and southern water to Shijiu Lake, and that Tiansheng Bridge Sluice is the north-south marker of the divide.

The line of the divide is given point by point at greatest length in the Near-Term Implementation Plan of the Territorial Spatial Plan of Lishui District (February 2021): from Jiuligang, in Jurong City above the Dongfang Reservoir, by Wangjiapeng to Zhujiabian within the district, along the Yuanbai Highway (high ground) to the district tea farm, Qiligang, Hejia Mountain, Guantang, Zhizigang and Luzi Mountain, then in succession to the main peaks of Qiuhu Mountain, Shuangjian Mountain, Ma'an Mountain and Ping'an Mountain, across the Tianshengqiao River at Tiansheng Bridge Sluice, to Yanzikou at the main peak of Xiaomao Mountain, then by Pengjia, Mashang Mountain, Zhaijia, Zuo Mountain and Wangjiadian, past Luojia into Anhui, turning north-west into Xiheng Mountain. The Master Plan for the Wuxiang Mountain National Forest Park, Nanjing (2023–2035) carries a largely identical passage, but stops at the main peaks of Qiuhu, Shuangjian, Ma'an and Ping'an mountains and omits the stretch from the Yuanbai Highway to Luzi Mountain. The two corroborate one another and neither corrects the other.

The direction in which the land falls on either side of the divide is given more fully in the district government's 2024 plan than in its 2019 one: taking the divide as the line, the northern Qinhuai system falls from south-east to north-west while the southern Shijiu Lake system falls from the north-east in two directions and meets in the lake area, so that the terrain overall is distinctly stepped. Both plans record that Lishui lies in the Ningzhenyang hill country, that hills make up 72.5 per cent of the total area and that the district high point is 368.5 m, but only the 2024 document sets out those directions of fall.

There is a further ridge line at the western end of the divide. An introductory article in the Shiqu Subdistrict column of the district government website, published in September 2025, records that the back of Xiheng Mountain sends the Hengshan water north into the Qinhuai and the streams running south into Shijiu Lake, making the mountain the divide between the two systems. The article is a promotional piece and gives neither the height nor the area of Xiheng Mountain; "Hengshan water" is its name for the run-off from the mountain's northern slope and is not a river name in the register of watercourses. The same article lists Xiaomao Mountain among the sights of Shiqiu Subdistrict, which corroborates the clause in the Near-Term Implementation Plan that the divide reaches the main peak of Xiaomao Mountain at Yanzikou, so that Xiaomao Mountain belongs to the Shiqiu area.

River allegiance is set out system by system. On the Shijiu Lake side, the district government's geographical position page gives the main inflowing rivers as the Xinqiao River (26.28 km), the Yunhe River (11.99 km) and the upstream stretch above Tiansheng Bridge Sluice (6.3 km). On the Qinhuai side, the same page gives the Lishui River as 6.5 km, the Yigan River as 22.1 km, the Ergan River as 25.60 km and the Sangan River as 11.19 km, with the downstream stretch of the Tianshengqiao River below the sluice as 8.7 km.

Article 5(1) of the Measures for the Management and Protection of Water Conservancy Works in Lishui District (Lu Zheng Gui [2022] No. 2) names the main rivers and lakes in two groups: Shijiu Lake; and the Lishui, Yigan, Tianshengqiao, Ergan and Sangan rivers together with the Xinqiao River (including the Baima River) and the Yunhe River. The second group has seven members, which are the seven main rivers recorded on the district government's natural resources page. The measures write the Xinqiao River as including the Baima River; the Baima is a component of the Xinqiao and this site does not count it as a seventh river.

The Tianshengqiao River spans both systems: the district government's geographical position page places its upstream stretch (6.3 km) in the Shijiu Lake system and the stretch below the sluice (8.7 km) in the Qinhuai system, while the Near-Term Implementation Plan records that the divide crosses the Tianshengqiao River at Tiansheng Bridge Sluice and that the river links the northern and southern systems. The two stretches of one river belong to two systems; this entry records both allegiances and does not write the whole river as belonging to one.

The water pattern within the hill country comes from the forest park plan: the park's divide is V-shaped, with northern water leaving by the Yigan and Lishui rivers for the Qinhuai and southern water by the Xinqiao or Tianshengqiao river for Shijiu Lake; within the park Wuxiang Temple, Xiangshan, Qiuhu Mountain and Taohuaba Reservoir belong to the Shijiu Lake system and Wangjiadian Reservoir to the Qinhuai. The same plan gives the Yigan River as 20.35 km with a catchment of 172.98 sq km, the Ergan River as 26.36 km with a catchment of 227.10 sq km, and the Sangan River as 11.19 km within Lishui.

Periods and areas

This entry is not divided by period: the sources available give no comparable basis for dating changes in natural watercourses. It is divided three ways, all following official figures.

By catchment, using the district government's geographical position page:

• The Qinhuai basin, 464.82 sq km: the north of the district, falling from south-east to north-west, with water flowing north to the Qinhuai.
• The Shijiu Lake basin, 599.39 sq km: the south of the district, falling from the north-east in two directions and meeting in the lake area.
• The western Taihu region, 2.73 sq km: a single tract of hill country in the south-east corner, the only part of the district outside the other two.

By the divide, using the Near-Term Implementation Plan and the two district plans: the divide runs east to west across the middle of the district, with the Qinhuai system to its north and the Shijiu Lake system to its south; Tiansheng Bridge Sluice marks the parting and Xiheng Mountain is a ridge line at its western end. The divide begins at Jiuligang in Jurong City and ends at Xiheng Mountain, passing in succession the main peaks of Qiuhu, Shuangjian, Ma'an and Ping'an mountains, and crossing the Tianshengqiao River at Tiansheng Bridge Sluice.

By river allegiance, using the river register on the district government's geographical position page and in the water conservancy measures:

• On the Qinhuai side: the Lishui, Yigan, Ergan and Sangan rivers and the stretch of the Tianshengqiao River below the sluice.
• On the Shijiu Lake side: the Xinqiao River (including the Baima River), the Yunhe River and the stretch above the sluice.
• Spanning both: the Tianshengqiao River, with the stretch above the sluice in the Shijiu Lake system and the stretch below it in the Qinhuai.

A separate set of restoration zones is laid out in the pre-approval draft of the Territorial Spatial Ecological Protection and Restoration Plan of Lishui District (2021–2035), made public in July 2026: the north-western Qinhuai basin ecological protection and restoration zone, 177.65 sq km; the north-eastern urban and rural living environment improvement zone, 260.85 sq km; the south-eastern low hill ecological conservation zone, 384.18 sq km; and the south-western lake-side wetland protection and restoration zone, 240.99 sq km, with two axes, one for the Qinhuai and one for the Shijiu Lake system. These are ecological restoration zones, not catchments, and the two sets of areas are not interchangeable.

Open questions

• Two figures for the number of main rivers: seven (district government, geographical position and natural resources pages; the water conservancy measures name them as the Lishui, Yigan, Tianshengqiao, Ergan and Sangan rivers, the Xinqiao River and the Yunhe River) and eight (pre-approval draft of the Territorial Spatial Ecological Protection and Restoration Plan of Lishui District 2021–2035, July 2026). The latter does not name them, and this site does not supply a name for an eighth.
• Several figures for river lengths: the Yigan River as 22.1 km (district government, geographical position page), 20.1 km (Jiangsu Provincial Department of Water Resources, 3 July 2023) and 20.35 km (forest park plan); the Ergan River as 25.60 km (geographical position page) and 26.36 km (forest park plan); the Sangan River as 11.19 km in both. The catchments of 172.98 and 227.10 sq km have been found only in the forest park plan, with no equivalent from a water resources department.
• The two stretches of the Tianshengqiao River (6.3 km above the sluice and 8.7 km below it) come from the district government's geographical position page; their sum, 15 km, is not an official length for the whole river and this entry does not add them together.
• The statement that Xiheng Mountain is the divide between the Qinhuai and Shijiu Lake systems has been found only in one introductory article in the Shiqu Subdistrict column of the district government website, with nothing from a water resources, forestry or natural resources department; the article gives neither height nor area, and "Hengshan water" is its name for run-off from the northern slope, not a river name, so the wording is qualified.
• The line of the divide is given in two mutually corroborating texts (Near-Term Implementation Plan, February 2021, and forest park plan, March 2024 version). The latter omits the stretch from the Yuanbai Highway to Luzi Mountain. The two corroborate one another and neither corrects the other; Jiuligang and Wangjiapeng lie in Jurong City, outside the district, and this site records the wording without describing that ground.
• Catchment area and lake area are not interchangeable: the 599.39 sq km of the Shijiu Lake basin is a catchment, while the lake's own area is given in two figures, 207.65 and 214.7 sq km. They differ in order of magnitude and in meaning.
• The Qinhuai's whole catchment of 2631 sq km and its length of 110 km from the northern source to the Sancha River mouth (Jiangsu Provincial Qinhuai River Water Conservancy Project Management Office) are figures for the whole basin and are not the same statistical range as the 464.82 sq km of the Qinhuai basin within Lishui (geographical position page); the two may not be compared or subtracted.
• The Periods and areas section sets out no periods in time: the available sources give no comparable basis for dating changes in natural watercourses, and this site does not infer such periods from the history of administrative divisions or from the first appearance of watercourse names.