What three rivers do "Three Rivers" refer to?

"Sanjiang refers to Jinsha River, Lancang River and Nujiang River. The Jinsha River, Lancang River, Nujiang River and Yarlung Zangbo River in the east are all rivers originating from the Qinghai-Tibet Plateau with a large flow. "

Sanjiang plain, also known as Sanjiang lowland, is located in the northeast of Northeast Plain, which is the largest swamp distribution area in China. The "Three Rivers" in the Sanjiang Plain, namely Heilongjiang, Wusuli River and Songhua River, are vast and collect alluvial deposits, forming this low fertile soil. The area is rich in water resources, with a total amount of 65.438+08.764 billion cubic meters.

The per capita arable land area is roughly five times the national average, and there are 2.52 million hectares of mixed coniferous and broad-leaved forests in hilly areas.