三门峡水库蓄清排浑运用以来库区冲淤演变初步分析

Preliminary analysis of scour and silting evolvement in Sanmenxia reservoir area since the operation of storing clear water and releasing muddy

水库蓄清排浑运用以来 ,黄河潼关 1974～ 1986、1987～ 1995、1996～ 2 0 0 2年均水量较 195 0～ 195 9年减少9 1% ,35 5 %、5 5 5 % ,沙量减少 4 0 9%、4 9 6 %、6 6 2 %。潼关以下三个时段年均淤积量为 0 0 4 2、0 16 1、0 2 0 8亿m3。呈水沙量递减 ,淤积量递增趋势。潼关同流量水位 2 9年升高 2 31m ,受上游冲淤下延影响升高 1 0 5m占 4 5 5 % ,其他因素影响升高 1 2 6m占 5 4 5 %。小北干流非汛期冲刷、汛期淤积格局未变 ,反映了水库运用对小北干流没有明显影响。渭河华县站 1974～ 1986年水量较大 ,渭淤 1～ 10断面仅淤积 0 0 6 5亿m3,华县同流量水位升高 0 0 3m。以 1974～ 1986年为准 ,1987～ 1995年、1996～ 2 0 0 2年华县年均水量减少 2 2 8%、5 6 2 % ,年均沙量减少 11 6 %、34 4 %。渭淤 1～ 10断面 1987～ 1995年淤积 1 72亿m3,特别是 1994和 1995年的中小洪水 ,汛期淤积 0 85亿m3主河槽萎缩 ,华县同流量水位升高 1 0 7m。

Since the Sanmenxia reservoir used the operation of storing the clear water and releasing the muddy, the average annual flow at Tongguan for the three periods from 1974 to 1986, 1987 to 1995, and 1996 to 2002 reduced by 9 1%, 35 5%, and 55 5% respectively compared with the period from 1950 to 1959 Correspondingly, the annual sediment reduced by 40 9%, 49 6%, and 66 2% at the same periods. The annual depositions in the reservoir area below Tongguan for the three periods are 4 4, 16 1, and 20 8 million cubic meters respectively. This fact shows that the deposition gradually increased with the decrease of incoming flow and sediment. In the past 29 years, the water stage of same flow discharge at Tongguan rose by 2 31m, of which 1 05m, accounting for 45 5%, came from the influence of the deposition in the upper reach, and the rest 1 26m, accounting for 54 5%, came from other factors. The fact that the character of deposition in flood season and erosion in non_flood season in Xiaobeiganliu didn't change indicates that the operation of Sanmenxia reservoir didn't make an obvious affect to Xiaobeiganliu. From 1974 to 1986, due to the large incoming flow at Huaxian station, the accumulative deposition in the reach of cross section 1 to 10 in the lower Weihe River is only 0 065×10 8 m 3 and the water level of same flow discharge rose by just 0 03m. However, the average annual flow at Huaxian reduced by 22 8% and 56 2% respectively for the periods from 1987 to 1995 and 1996 to 2002 compared with the period of 1974 to 1986, which caused a severe deposition in the reach of cross section 1 to 10 and the water level of same flow discharge at Huaxian station rose by 1 07m.