Songhua River
Source: Ministry of Water Resources website
One of China's seven major rivers, Heilongjiang is the largest tributary in China. Songhua River was called difficult River in Sui Dynasty, Nashui in Tang Dynasty, Yazi River and Mixed Tong River in Liao and Jin Dynasties, and Mixed Tong River and Songhua River in Qing Dynasty. Songhua River flows through Jilin and Heilongjiang provinces; the basin area is 557,200 square kilometers, covering Heilongjiang, Jilin, Liaoning and Inner Mongolia in the four northeastern provinces; annual runoff is 76.2 billion cubic meters.
According to the topography and channel characteristics of Songhua River, it can be divided into upper, middle and lower sections.
The upper reaches of the river, from Sancha River to Harbin City, are 240 kilometers long, with a catchment area of 30,000 square kilometers. The river runs through grasslands and wetlands in Songnen Plain. The slope of Sancha River to Xiadai Jipo falls slowly to 0.022 and that of Xiadai to Xiejiatun is 0.06 and that of Xiejiatun to Harbin is 0.052%. There are fewer tributaries in this section, and there are large tributaries near Xiadaiji, Lalin River confluence.
In the middle reaches of the river, Harbin to Jiamusi City is the middle section of the Songhua River flowing eastward with a river length of 432 kilometers. From Harbin to Tonghe, the gradient of the river is relatively flat, ranging from 0.055 to 0.044 with the largest tributary on the left bank, the Hulan River confluence. Down 20 km, the river enters a 130 km low hilly area. The two sides are the transition zone between Zhang Guangcai Ling and Xiao Xing'an Ling. The Valley is narrow. The two sides are high plains and hilly areas. On the left bank, there are tributaries of Shaoling River and Mulanda River, and on the right bank, there are ants River. From Tonghe County down about 70 kilometers, into the famous "three surnames" shoal area of Dongliu Songhua River, the shoal area is about 27 kilometers long, the water surface of the river is 1.5-2.0 kilometers wide, the slope is 0.06-0.15, the water depth is more than 1 meter in the middle and low water periods, the water depth is less than 1 meter in the dry water period, and the flow speed is only 1 meter/second. The shipping waterway is 500-600 meters wide. There are many islands and sandbars in the river, and there are reefs. There are many rocks that burst out of the water. It is a well-known section of the Songhua River that hinders navigation. After the Sanxing shoal, there are large tributaries on the right bank, Mudan River and Junken River converge, and Tangwang River converges on the left bank. The water surface of this reach is gradually widening and the water depth is gradually increasing. Near the urban area of Jiamusi City, Songhua River is fairly straight. Its main channel is 800-1300 meters wide, its water depth is 8-11 meters, and its slope is 0.1.
The lower reaches of the Yangtze River, from Jiamusi to Tongjiang, are the lower part of the Songhua River flowing eastward with a total length of 267 kilometers. It runs through the Sanjiang Plain. The two sides of the river are alluvial plains with flat terrain and overgrown weeds. The rivers and beaches are relatively open. The divergence of the channels is vertical and horizontal. The width of the beaches is 5-10 kilometers. There are many shoals in the middle of the river. Songhua River is injected into Heilongjiang Province in the northeast of Tongjiang City. The whole lower reaches of the river are low and flat. It has always been one of the key areas for flood control. There are two tributaries of Wutong River and Dulu River in the lower reaches.
