Yigan River

Overview

The Yigan River is a main watercourse of the Qinhuai system. It rises at Zhongshan Reservoir, runs through Lishui District and Jiangning District, and joins the Sangan River at the Wangjiawei ferry before flowing into the Lishui River (Jiangsu Provincial Department of Water Resources, 3 July 2023). Flowing into the Lishui River is the meeting of one main watercourse with another, and this site does not rewrite it as flowing into the Qinhuai.

Its length is given in three ways: 22.1 km on the district government's geographical position page; 20.1 km in the Jiangsu Provincial Department of Water Resources' notice of administrative permission; and 20.35 km with a catchment of 172.98 sq km in the Master Plan for the Wuxiang Mountain National Forest Park, Nanjing (2023–2035). This entry takes the 22.1 km of the geographical position page; the three are shown side by side under Open questions.

The river belongs to the Qinhuai basin: the district government's geographical position page lists the Yigan River in the Qinhuai system, alongside the Lishui, Ergan and Sangan rivers.

Subdistrict: the official sources say only that the Yigan River runs through Lishui District and Jiangning District, without naming the townships within the district. The only indirect statement found is in the 2018 annual implementation plan for water pollution prevention, which records that the assessment unit for the Zhongshan Reservoir cross-section is Yongyang Subdistrict; Zhongshan Reservoir is the source of the Yigan River, so this entry's subdistrict gives Yongyang Subdistrict only, and no other township is inferred from the length.

Formation and change

The Yigan River is one of the district's seven main watercourses (district government natural resources page).

Ecological level and base flow: the Lishui District 14th Five-Year Water Plan draws up the Lishui District Ecological Water Level Assurance Plan for the First Batch of Important Rivers, the Yigan River, and lists the Yigan River among the fifteen rivers for which an ecological base flow, or base level, is set.

Channel improvement: the Yigan River improvement works between the Shahe mouth and the Changhe expressway bridge cover 3.93 km, comprising desilting, strengthening of the embankment, ecological stone gabion revetment, rebuilding of a drainage pumping station, rebuilding of bridges and culverts, and new and upgraded asphalt flood defence roads (Jiangsu Provincial Department of Water Resources, 3 July 2023). The notice covers this reach only and does not mean that the whole river has been improved.

No first-tier source has been found for when the Yigan River was cut, for realignments or for its final alignment, so nothing is written here.

Landscape and visiting

The relation of hill and water: the Master Plan for the Wuxiang Mountain National Forest Park, Nanjing (2023–2035), records that 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; the Yigan River is the outlet for the park's northern water. The same plan records that Wangjiadian Reservoir within the park belongs to the Qinhuai system.

No first-tier source has been found for footpaths, waterside platforms, viewing facilities or opening information along the Yigan River, so no visiting detail is given; readers who need it should go to the official notices of the district water department, the district culture and tourism department and the local subdistricts. Information is current to September 2026.

Open questions

• Three figures for the length: 22.1 km (district government geographical position page, the value used here), 20.1 km (Jiangsu Provincial Department of Water Resources, 3 July 2023) and 20.35 km (Master Plan for the Wuxiang Mountain National Forest Park, 2023–2035). All three are shown and none is chosen.
• The catchment of 172.98 sq km has been found in the forest park plan only, with no equivalent figure from a water department; it is cited with its source.
• The subdistrict has no direct source: the official sources say only that the river runs through Lishui District and Jiangning District, without naming the townships within the district. This entry gives only Yongyang Subdistrict, that of the source at Zhongshan Reservoir; the other townships along the river await a second source.
• Flowing into the Lishui River and flowing into the Qinhuai are not the same statement: the Lishui River is itself a main watercourse of the Qinhuai system, and the Yigan River flows first into the Lishui River and so reaches the Qinhuai.
• The Yigan, Ergan and Sangan rivers are all main watercourses of the Qinhuai system; the length and catchment of each are recorded in its own entry, and this site neither adds them together nor uses them to work out the area of the Qinhuai basin.