The Wula River, a tributary of Heilongjiang, originated in Russia. What river is it?

It is the main tributary of Heilongjiang. The upper reaches of the river are formed by the confluence of the Wula River and the Dobby River, flowing northeast to Boli area, making a sharp turn southwest and pouring into Heilongjiang. The Wusuli River is 880 kilometers long with a drainage area of nearly190,000 square kilometers. From the place where its tributary Songgacha River is injected to the place where the river meets Heilongjiang, it is the boundary river between China and the Soviet Union. The Wusuli River basin is rich in fertile land, dense forests and minerals, and is rich in soybeans and sorghum. Aquatic products are also extremely rich, including redundant flower fish, bighead carp, sturgeon, Oriental Pearl (pearl), and specialty salmon, the largest of which is four or five meters long and weighs seven or eight hundred kilograms. This kind of fish is extremely rich in flood season, which is simply amazing. According to the Records of Heilongjiang, "Every autumn, people swim upstream from the sea and cannot drive into the river, so thick that some locals actually cross the back of the fish." The Wusuli River has an ice age of more than four months every year, and it is completely navigable. The river has become a smooth road for sledding, but it can still be used for ice fishing. There is an island about two kilometers long on the Wusuli River called Zhenbao Island, which is located at 46.5 degrees north latitude and near 0/34 degrees east longitude. Originally it extended from China to Wusuli Peninsula, and later it became an island after a long-term impact of water. Now, in the dry season of summer, Treasure Island is still connected with the land of China on the Wusuli River, restoring the original appearance of the peninsula. The older generation of fishermen in China who worked on the Wusuli River called Zhenbao Island "Weng Island". The climate here is very cold in winter, with the lowest temperature as low as MINUS 38 degrees Celsius and the average temperature around MINUS 20 degrees Celsius. The average temperature in summer is around 22 degrees. There is a great difference in temperature between cold and summer. The ice age was very long, as long as five months.