鄱阳湖与长江关系及三峡蓄水的影响

通过机理研究,结合实测资料分析,说明了鄱阳湖河相与湖相的分界水位,阐明了长江干流来流对湖口出流的顶托作用,并给出了湖口出现倒流的条件,得到了鄱阳湖对洪水的调节作用系数,初步理清了鄱阳湖与长江干流江湖相互影响规律。分析了三峡水库蓄水期的影响及鄱阳湖的枯水特性。三峡水库运用初期,其蓄水的前半段时间,鄱阳湖向长江干流多补水量23亿m3,后半段少补水量11亿m3。三峡水库运用30年后,在河道冲刷、可补水量减少和蓄水的共同作用下,鄱阳湖的枯水季节相当于提前了1个月左右。本研究对认识江湖关系及鄱阳湖治理具有重要意义。

Relationship between Poyang Lake and Yangtze River and influence of Three Georges Reservoir

Based on the mechanism study and data analysis,this article revealed the water level of the Poyang Lake dividing the lake phase and river phase,clarified the effect of Yangtze River water flow on the out flow of the lake,deduced the condition of the occurrance of backward flow,and derived the coefficient of the regulation effect of the lake on flood.The relation between the Poyang Lake and the Yangtze River is clarified.By analyzing the characteristis of the Poyang Lake,the influence of the Three Georges Reservoir storage in dry season is studied.It is found that in the early period of the operation of Three Georges Reservoir,in the forepart of impounding period,the Poyang Lake increased water by 2.3×109m3 to the river.But in the second part of impounding period,the Lake reduced water supplies by 1.1×109m3 to the river.It is predicted that after thirty years of the Three Georges Reservoir put into operation,due to the influences of the Three Georges Reservoir storage and riverbed erosion,the dry season of Poyang Lake will be shift to one month in advance.