嘉陵江上游最大支流,古称桓水,始见于《尚书·禹贡》:“織皮、西倾因桓是来”意即梁州的贡物由西倾山顺着桓水前来。織皮谓西戎之国,即昆仑等是也;西倾,山名,在甘肃、青海交界处,绵亘千余里;桓,桓水,即白水,今名白龙江。《水经注》:“白水出西倾山,流注汉水。”《辞海》:“桓水,古水名,即今白龙江,发源于西倾山南,屈曲东南流至今甘肃舟区县东与古羌水即今岷江合,又东南至今文县与古白水即今白水江 The largest tributary of the upper reaches of the Jialing River, the ancient name Huan water, began in the ”Book of Yugong“: ”woven skin, west tilt due to Huan is “ means that Liangzhou tribute from west to mountain along Huan. Tissue leather that the country of West China, that is, Kunlun is also; West dumping, mountain name, at the junction of Gansu and Qinghai, stretches for more than a thousand years; Huan, Huan water, that is, white water, now Bailongjiang. ”Water by the note“: ”white water out of the West pouring mountains, flowing Hansen. “ ”Ci Hai“: ”Huan water, the ancient water name, now Bailongjiang, originating in the West tilt Shannan, Southeast buckling flow Gansu Zhou area East County and the ancient Qiang water is now Minjiang River together, but also from the southeast to now Wenxian and ancient white water that is now Whitewater