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变动回水区河段的侵蚀基准面在蓄水期抬升,在消落期和汛期逐渐恢复为天然状态,其冲淤调整特点不同于自然条件.以三峡库区嘉陵江与长江交汇河段为例,分析了175m试验性蓄水期前后交汇河段冲淤特性的变化.结果发现,175m试验性蓄水以前,交汇河段由于上游来沙持续减少出现了累积性冲刷,175m试验性蓄水以后,侵蚀基准面的抬升抑制了交汇河段的冲刷发展态势;其中支流嘉陵江来沙量减少的程度高于长江干流以及2008-2012年汛期汇流比大于2003-2007年,使得嘉陵江支流河段继续冲刷,而长江干流河段转为淤积.175m试验性蓄水前后交汇河段年内汛淤枯冲的基本规律未变,但主要走沙期由汛后推迟到了次年的水位消落期,走沙量减少.
The erosion datum of the fluctuating backwater area reaches up during the water storage period and gradually returns to the natural state during the ebb and flood season, and the characteristics of scouring and silting adjustment are different from the natural conditions.Taking the intersection of the Jialing River and the Yangtze River in the Three Gorges reservoir area as an example , And analyzed the variation of scouring and silting characteristics before and after the 175m experimental period.The results showed that before the 175m experimental period, accumulative scour occurred at the junction with continuous decrease of sediment flow in the upper reach, and after 175m experimental water storage , The elevation of the erosion datum refrains the trend of scouring at the intersected river; the sediment concentration of the Jialing River in the tributaries decreases more than that of the Yangtze River and the confluence of the flood season in 2008-2012 is greater than that in 2003-2007, which makes the branch of the Jialing River continue to scour , While the mainstream of the Yangtze River turned into siltation.The basic law of flood and slush before and after the experimental reach of 175 m of experimental impoundment remained unchanged during the year, but the main strike-away period was postponed from the flood season to the next flood season, Decrease