Abstract:

With the construction of huge cascaded reservoirs,the water and sediment regime in the upstream basin of Yangtze River has been changed. The authors statistically analyzed the variations of runoff and sediment transport at major hydrological control stations in the mainstream and tributaries of Yangtze River based on over 5-decade’s hydrological data. It’s revealed that the annual average runoff measured at almost all the major stations has been decreasing,down 4%-24%,except for Pingshan station in Jinsha river,whose runoff variation was not obvious. On the other hand,the annual average sediment transport at all major stations has been decreasing more evidently by 30%-88%. Moreover,the new situation and problems posed by the construction of huge cascaded reservoirs on the upper Yangtze River and the countermeasures are discussed.

Key words: upper Yangtze River , reservoir construction , runoff and sediment variation , variation regularity , countermeasures