Ranwu Lake is located at southwest of Qmado Prefecture, borders on Nyingchi Prefecture. The altitude of the lake surface of Ranwu Lake is 3800 meters. The area of lake surface reached 22 square meters. It is the largest lake in Southeastern Tibet.
To go to Nyingchi from Qamdo along Sichuan-Tibet Highway, you will see a corner of Ranwu Lake in Bome County. The melting snow from snow mountains around Ranwu Lake becomes main runoff source of Ranwu Lake. Ranwu Lake is not a common round lake. The Ranwu Lake is very narrow and long. It is about 20 kilometers long and 1 to 5 kilometers wide. Ranwu Lake is a quake lake formed for collapse of mountain. It was the river course of Palong Zanpo which is the main branch of Yarlung Zanpo River. About 200 years ago, a corner of the giant mountain on the bank of river collapsed. Numberless giant rocks and detritus blocked the river course.
Because the river course blocked, water could not flow out and accumulated in river valley. Quickly, beautiful trees on both banks of river were submerged, and the water level increased. One day, water broken through the block of rocks, formed a water course and flowed into Palong Zanpo.
To walk along the bank of Ranwu Lake, you will feel mountains on both sides like walls. The Ranwu is the transliteration of Tibetan Language. It means "lake which is piled up with corpses". There is a popular legend in about Ranwu Lake. Long time ago, there was a water buffalo living in Ranwu Lake and a ox living on bank of Ranwu Lake. They often fought for domain at night. When they fought with each other at night, the noise was so loud that local people can not sleep. Then, local villagers came up an idea to catch them. One day night, all villagers came out to catch them with torches and iron chains when they fought. Once found people there, they disappeared. Like this, villagers failed for several times. Then, they asked help from Lama in monastery.
Lama told villagers that they are holy oxen. Common people can not catch them. Later, a handsome young boy came to the village and said that he can catch the ox. At night of this day, the handsome young boy appeared in front of the oxen when they fought. He shouted to oxen that "go back to your seat, or I will punish you". Oxen turned back their heads and found that the young boy was Padmasambhava.
They were so surprised that they turned over to the both banks the lake and became two giant mountains. The Ranwu Lake is in the middle of these two mountains. Then, local villages had peaceful life. In order to commemorate the merit of Padmasambhava, villages built a monastery to enshrine Padmasambhava in the village.
Although folk legend is myth, it is not completely without any reason. Geographer told us that the Ranwu Lake was really formed by three oxen. These three oxen are the Himalayas, Nyainqêntanglha Range and Hengduan Mountain.