After Putting Into Operation Of Xiaolangdi Reservoir The Research For Sanmenxia Reservoir Operation Scheme

The Sanmenxia Project is one of the key projects built during the first phase of the Yellow River Rectification. It has played a very important role in both the flood control and the integrated utilization of the water resources in the Yellow River. However, it also has undergone some turbulent periods during its construction and operation, e.g. it has experienced twice the reconstruction and the adjustment of operation schemes. In general, the history of the construction and management of the Sanmenxia Project has become very useful for the development and management of the sediment-rich rivers.After the Xiaolangdi Reservoir was put into operation and the input of water and sediment into the Sanmenxia Reservoir has changed, how to adjust the operation schemes of the Sanmenxia Reservoir has been one of hottest topics in the water resources domain. For the time on, Tsinghua University, China Water Resources Institute and some other organizations are carrying out the researches of the four possible adjustment schemes, considering the factors influencing the Tongguan elevation, the methods of controlling Tongguan elevation, and the current situation of the Sanmenxia Reservoir. The Ministry of Water Resources has also organized the prototype experiments of altering the operation scheme of the Sanmenxia Reservoir. It is certain that the alteration of the operation scheme of the Sanmenxia Reservoir will bring lots of problems to the operation of the Sanmenxia Reservoir, and to the economical development and ecological environments of the reservoir area down from the Tongguan.Through the survey in the fields and the collection of the historical data, the construction and operation history of the Sanmenxia Reservoir during the past 43 years and the factors influencing the Tongguan elevation has been discussed in this thesis. The ecological environments of the reservoir area down from the Tongguan, the effects of the reservoir on the wetlands, the reservoir displacement, and the impacts of "Store Clear Water, Discharge the Sediment Water" scheme on the reservoir economy are also been presented. According to the prescribed water and sediment input and the water level of each new operation scheme, the hydropower output of the Sanmenxia Hydropower Station is calculated and the impacts on the operation of the Sanmenxia Reservoir are analyzed.The comparisons of the impacts on the reservoir ecological environments, reservoir displacement, and the industrial and agricultural water withdrawal under the different water levels have also been done. The efficiencies of different operation schemes in lowering the Tongguan elevation are preliminarily analyzed.It is suggested that the reasonable Tongguan Elevation index should be determined and the efficient reservoir operation schemes, together with other measures, should be adopted to lower the Tongguan elevation. In this way, the impacts caused by the adjustment of operation schemes on both the Sanmenxia Reservoir and the reservoir area down from Tongguan can be reduced, thus the sustainable development of the Sanmenxia Project and the reservoir area can be promoted.