龙刘水库联合运用对宁蒙河道冲淤的影响

Effects of joint operation of the Longyangxia and Liujiaxia Rservoirs on scouring and sedimentation of the Ningxia-Inner Mongolia Reach

通过对水流连续方程、水流动量方程和河床变形方程进行离散化处理,建立宁蒙河道的水文水动力学冲淤计算模型,利用该模型对龙刘水库联合运用对宁蒙河道冲淤的影响进行了计算和分析。选取龙刘水库联合运用初期的1987—1990年为计算时段,在相似的引水条件下研究龙刘水库运用对河道冲淤的影响,计算水沙未还原、水沙均还原、只还原水不还原沙和只还原沙不还原水等4种水沙条件下宁蒙河道的冲淤状况。结果表明,龙刘水库联合运用对宁蒙河道起到了增淤的作用,龙刘水库运用后,其蓄水所引起的河道淤积效应大于其拦沙所引起的河道减淤效应。

Based on the empirical generalization of the flow continuity equation, the flow momentum equation and the riverbed deformation equation, a computational model was established for the research on the scouring and sedimentation of the Ningxia-inner Mongolia Reach in the upper Yellow River. The effects of joint operation ofthc Longyangxia and Liujiaxia Reservoirs on the fluvial processes of the Ningxia-Inner Mongolia Reach were estimated and analyzed using this model. Taking the early operation stage of the two reservoirs （1987--1990） as calculating period, the scouring and sedimentation of the Ningxia-Inner Mongolia Reach was calculated under four kinds of water and sediment conditions. The results show that, joint operation of the Longyangxia and Liujiaxia Rservoirs increases the sedimentation of the Ningxia-Inner Mongolia Reach, the effect of sedimentation increase due to water storage is greater than the effect of deposition reduction resulting from sediment retaining.