三峡水库库尾泥沙减淤调度研究与实践

Study and practice of the Three Gorges Reservoir regulations for sedimentation reduction in its tail region

三峡水库175m试验性蓄水后，库尾重庆主城区河段主要走沙期从天然情况下的9～10月份逐步延后至消落期的4—6月份。为加大消落期走沙能力，避免局部河段泥沙淤积引起的碍航问题，本文采用一维非恒定流水沙数学模型，研究提出了三峡水库库尾泥沙减淤调度方案。即当寸滩流量7000m^3／s左右，三峡坝前水位从160～162m开始集中消落、日降幅按0．4～0．6m控制，走沙效果较好。2012年和2013年消落期，根据上述研究成果，三峡水库成功实施了库尾减淤调度试验。试验期间，库尾重庆大渡口．涪陵段（含嘉陵江段）冲刷量分别为241．1、441-3万m^3，取得了较好的减淤效果。同时，应用2012年实测资料对模型计算结果进行了复核。与实测资料相比，模型计算结果在冲淤定性上是一致的，绝大部分河段在定量上也基本合理。

Afterthe impoundment of the Three Gorges Reservoir, major period of erosion in the tail reaches has gradually changed from the period of September to October undernatural condition to fluctuating period of April to June. In order to increase the erosion in fluctuating period and reduce the sedimentation in local reaches which may block navigation. Regulations to reduce sedimentation in the tail area of the reservoir are presented based on one-dimensional unsteady flow-sediment model. It is shown that better erosion effects can be achieved by controlling the stage in front of the dam within the range of 160-162m and the stage fall in a day within 0.4-0.6m in the condition of Cuntan flow about 7000m^3/s. According to these results, in-situ experiments were successfully completed in the fluctuating periods of 2012 and 2013. Analysis of the measured data indicate that the total erosion in the tail reaches is 2.411 and 4.413 million m^3 during the two years＇ regulation periods respectively, a good effect in sedimentation reduction. The measured data in 2012 were used to validate the mathematical model. A comparison with the calculations shows that the model is effective in qualitative calculation of erosion and deposition and basically reasonable in quantities for most of the reaches.