Feasibility of lowering Tongguan elevation

Based on analysis of historical data before construction of the Sanmenxia Dam/Reservoir and a summary of the previous research,pointed out that the main cause for the serious situation of flood control in downstream of the Weihe River is the growing elevation at Tongguan site.Historical data of almost 2000 years showed that the annual sediment deposit was only 0.008 m before the dam construction.After the reservoir use,high water level is the main cause of raising Tongguan elevation.The change of elevation is directly related to operation of the reservoir.Our comprehensive analysis concluded that it is possible to lower Tongguan elevation without a significant decrease of the reservoir operation efficiency.Through rational management,Tongguan elevation 328 m at present may be lowered by 2m.This will help recover the flood control level of downstream levee of the Weihe River.The paper also proposed several suggestion in lowering Tongguan elevation based on investigational analysis.