Why is Jilin city important to navigation on the Sungari River?

Jilin city is historically and geographically significant to navigation on the Sungari River because it is situated at the river's head of navigation.1

This strategic importance dates back to 1651, when the Manchus established a shipyard in the area to construct boats for both transport and defense along the river. Today, while larger steamships can navigate the river as far as Harbin, Jilin city remains accessible to small river steamers, marking the upper limit for this type of waterborne transit.23