关于长江正源的确定问題

DETERMINATION OF THE MAIN SOURCE OF THE YANGTZE RIVER

江源水系诸河,地处青藏高原腹地,因人迹罕至,对那条河是长江正源,历史上并没有一个统一的认识可以遵循。通过考察后,在江源诸河中,论长度,沱沱河(包括源头冰川)最长,当曲稍次;论河道上下游的一致性,尕尔曲最顺,沱沱河其次;而论水量,当曲最丰,沱沱河其次。综合以上因素,我们认为沱沱河长度既长,方向又顺,应为长江正源。 综合上述观点,我们算得:由沱沱河源至四川省宜宾,长3474公里;宜宾至长江口约为2806公里。由于长江中下游下流主泓经常摆动,入海口段已有相当延长,故长江全长约为6300公里。

Usually a river has several headwaters on its source, but how to define the main source of a river lacks a univerally accepted principle or criterion. Some rivers define their main sources according to their lengths, and others define their main sources according to the traditional habit of the people .Under normal conditions, the traditional habit of the people coincides with the general flow direction of the river course, that is, if we make a survey from the plan map of a river network it looks like a natural extention of its way from lower reaches to upper reaches. However, the quantity of water in a river usually doesnot define the main source.The source region of the Yangtze River headwaters is situated in the hinterland of Qinghai - Xizang plateau, which is an unlraveled region, so thah a consensus of opinions about where the main source of the Yangtze River rises is not yet attained .After thorough investigation, among the various headwaters of the Yangtze River, the Tuotuohe River is the longest (including the glacier on headwaters) by length, and the Dangqu River is slightly shorter. As to the criterion of unanimous direction of streams, Garqu River is the smoothest, and the Tuotuohe River next; by the discharge of water, Dangqu River ranks the biggest and Tuotuohe River the second gumming up the above considerations, the Tuotuohe River is both the longest and with approximately the same direction of streams.For this reason, we consider that the Tuotuohe River should be the main source of the Yangtze River.In accordance with the above standpoints, We have computed the length of the rivev section from the headwaters of the Tuotuohe River to Yibin of Sichuan province to be 3174 km; and the length of that section from Yibin to the river mouth about 2806 km.Since the main channel of Middle and Lower Yangtze Rivers swing bank-to-bank frequently, and the section of river mouth has extended for a considerable distance to the East China Sea, the length of the Yangtze River is about 6300 km.