2 RIVER PROBLEMS IN CHINA 



(1) The Liao Eiver; (2) The Hai Ho; (3) The Huang 

 Ho; (4) The Yangtse Eiver — including the 'Whangpoo; (5) 

 The Min Eiver; (6) The West Eiver; (7) The Eed Eiver. 



The map shows the basins of these streams. 



One of the most important features about Chinese Eivers 

 is the fact that the low flat areas ("deltas") which they have 

 built up at their mouths by the denudation of the high land 

 in which they and their tributaries rise, are subject to almost 

 annual inundation. 



This is due to the concentration of the rainfall in China 

 within the summer months so that the channels which are 

 sufficient to carry away the water during, say, ten months 

 of the year cannot hold the temporarily enormously swollen 

 volume during the other two months. In prehistoric periods 

 such annual inundations served to build up the plains by 

 the silt deposited and undoubtedly had man not appeared 

 the land would have steadily risen until the level became 

 so high that flooding would be exceptional. It would seem 

 therefore that these plains are geologically speaking young 

 and that the agriculturist found it necessary to use the bulk 

 of these areas before nature had completed them. Hence 

 from the earliest period in China's history we find levees 

 or dykes being employed to keep the rivers within their 

 normal bounds and it seems probable that the requirements 

 of humanity will compel this course to be perpetually 

 adopted. This has the somewhat curious result that it 

 accelerates the growth of the coast so that the past and 

 present operatons of the hydraulic engineer in China are 

 actually enlarging the territory at a greater rate than would 

 naturally occur. The question of inadequate channel 

 occurs in a peculiarly aggravated form in the Yellow Eiver 

 which will be referred to later. 



In this connection it may be mentioned that there is a 

 long standing controversy as to the respective merits of 

 dykes and dredging. 



The latter is of course the process of excavating 

 mechanically the bed of a stream. It is claimed for the 

 dyke on the one hand that by restraining the waters within 

 one comparatively narrow area they are compelled to scour 

 out a deep channel which will not deteriorate. On the other 

 hand it is asserted that judicious excavation of the bed will 

 so guide the flowing water that they will naturally deepen 

 the excavation and lower the flood level, while it is alleged 

 against the dyke system that the channel and flood level 

 will gradually rise so that the dykes will be eventually over- 

 tipped. In actual fact it seems that the conditions are so 

 complex that there is no absolute advantage in favour of 



