(Update: 28/08/2011)
The heartland of Vietnam The Red River (‘Song Hong’) stretches about 1,200km from its source in China’s Yunnan Province. Its two main tributaries, the Song Lo (also called the ‘Lo’, or ‘Clear’ River) and the Song Da (the Black River), swelling its volume to an average 5,000 cubic metres per second, rising to nearly 40,000 cubic metres per second in the summer rainy season.