潼关高程抬升成因相关分析

三门峡水库建库后，库区冲淤变化是潼关高程变化的内在动力和条件，水库运用方式和潼关上游来水条件的改变是库区冲淤变化的潜在原因；潼关上游来沙条件是造成潼关高程上升的唯一根源，但它与潼关高程之间的关系并不密切，它是介于水库运用方式和来水量之间对潼关高程起调节平衡作用的淤积体供应源；水库运用方式对潼关高程产生影响的实质是，通过抬高水流侵蚀基准面，降低水流比降和水流冲刷力，使潼关高程在年内得不到有效的冲刷而使潼关高程保持持续上升状态；潼Dian段河床变化是潼关高程变化的直观的、外在原因，它的作用就是根据库区冲淤变化，通过自身的调整，使其上游河床得到调整；潼Dian段的累计淤积量及Dian（土夺）高程对潼关高程具有重要的影响，但不是影响潼关高程升降的独立影响因素。

Cause of formation of riverbed aggradations at Tongguan

The Sanmenxia reservoir was put into operation in 1960,which is the pioneer water conservancy project after liberation in China on the Yellow River with the heaviest sediment load in the world.Lack of sufficient study in the characteristics of incoming water and sediment,serious sediment silt in the reservoir not only made Tongguan riverbed rise rapidly,but also caused environment upstream watershed of Tongguan seriously deteriorated,so the reservoir has been reconstructed twice and its operation mode has been improved three times,and It has also played an important role in flood control and icy prevention and has created rich experiences for maintaining effective storage for reservoir built on river with heavy sediment load.In this paper,based on analysis on riverbed evolution at Tongguan Reach after the Sanmenxia reservoir was put into operation,the authors think that the changes in erosion and silt in reservoir downstream of Tongguan is the inherent drive and precondition for the riverbed change in the Tongguan reach;the reservoir operation mode,the upstream incoming water and sediment of Tongguan is the potential cause for variation of erosion and silt in the reservoir,and are also the important factors to lead Tongguan riverbed elevation rising;the riverbed changes in the reach of Tongguan and Guduo is the intuitionnistic and extrinsic cause for the riverbed change at Tongguan,and its function is to have the upstream reach riverbed adjusted by itself changes according to the changes in erosion and silt in the reservoir;the accumulative silt amount between Tongguan and Guduo,and Guduo riverbed elevation are of important impaction on Tongguan riverbed elevation,but they are the dependent factors to lead Tongguan riverbed elevation rising;the main mechanism that operation mode of the reservoir exert impaction on Tongguan riverbed elevation is to reduce water surface slope and erosion capacity of flow by raising erosion datum plane of flow,and then to have Tongguan riverbed not to be effective eroded,thereby keeping Tongguan riverbed rising continually.