Sediment - related Comprehensive Measures to Ensure 'the River Bed Should not Rise with the Deposition of Sediment'

摘要

Since 1950, the total deposition of sediment on the lower Yellow River hit 10 billion tons with which the river bed has risen by 2 to 4 meters. Moreover, sine the mid — 1980s, due to the over- use of water resources, inadequate interference and some natural influence the remaining flow was usually too small to reach the river s environmental and ecological need. Also, the main course shrunk and the so - called "the second stage suspended river becomes more and more serious. Most of the main courses in the lower Yellow River are now above their nearby flood plains which are 4 - 6 meters higher than the ground outside the dikes. In some parts the cross — section bed slopes reach 1 per thousand to 2 per thousand which are much greater than the river slope(0.14 per thousand). As the "the second stage suspended river develop fast the possibility of cross — section flow direction and inclined flow direction occur more frequently. Thus, we need to do more to keep the safety of the dikes. So, to reduce and stop the rising of the river bed is now one of the most important tasks of the management of the Yellow River. To ensure "the river bed should not rise with the deposition of sediment" we need to use comprehensive measures to solve the problems causing by sediment. On the upper reach the importing of sediment should be stopped or reduced while on the middle and lower reaches regulation of the relationship of flow and sediment transport needs to be done to stop the deposition process. Only with all these measures can we maintain and protract the the life of the present river channel. The four goals, "The dike should not breach in flood; zero -flow should not occur in water shortage; the pollution should not exceed the standard during the deterioration of ecology; the river bed should not rise with the deposition of sediment , are the real meaning of a "healthy" Yellow River. Also, the four goals are the necessary qualifications to realize the sustainable development of the Yellow River. Of all the four goals the most difficult one is to realize "the river bed should not rise with the deposition of sediment". The key reasons for most Yellow River problem are limited flow with very high sediment transport rate and the un - balance of water and sediment. In order to ensure the channel bed should not rise with the deposition of sediment" we must deal with the problem of sediment deposition. At the same time, if we want solve the problem of sediment we need to use all kinds of measures together to stop both the importing and deposition of sediment. With the study of the characteristics of the Yellow River and practical measures ever used, this article explains the main ideas of the comprehensive measures dealing with the sediment of the Yellow River, which are "retaining, discharging, diverting, regulating, digging of sediment".