近50 a东江干流惠州河段河道演变分析

Evolution of Huizhou Section of Dongjiang River during Last 50 Years

为获得近50 a来东江干流惠州河段的演变规律及来水来沙变化对演变的贡献率,收集并分析了1964—2013年河道地形及来水来沙资料。结果表明,20世纪60年代航道大整治后,东江干流惠州河段河床总体表现为小幅冲刷;20世纪70年代至21世纪初,河床基本在自然条件下淤积;2003—2009年全河段河床大幅下切,断面平均的冲刷厚度为1.9 m,冲刷总量近为7 200万m^3;2009—2013年,河道有冲有淤,总体以冲刷为主,河床总冲刷量为1 447万m^3,冲刷速度放缓,河道演变由全河段冲刷转向边滩淤积、主槽冲刷,禁采区淤积、可采区冲刷。分析同时段来水来沙条件变化,输沙量的减少对河道演变的贡献率约17%,人类活动主导了东江干流惠州河段河道演变。

In order to obtain the evolution law of Huizhou reach of Dongjiang mainstream in recent 50 years and the contribution rate of income water and sedi-ment changes to its evolution,the topographic data of the river channel and the incoming water and sediment from 1964 to 2013 are collected and analyzed.The study finds that:1)After the channel regulation in the 1960s,the riverbed was generally slightly eroded;2)From 1970s to the beginning of the 21st century,the riverbed was basically deposited under natural conditions;3)During 2003 to 2009,the riverbed was eroded largely,the average scouring thickness was 1.9m and the total scouring amount was nearly 72million m^3;4)During 2009 to 2013,the riverbed was eroded in most section and deposited also in local section,the total scouring amount was 14.47million m^3,scouring velocity was slow down.In the past 10 years,with the continuous deepening of sand excavation management,the evolution of river in Huizhou section has changed from full reach scouring to bank silting and main channel scouring,no mining area silting and mining area scouring.The result showes that the largest contribution rate of income water and sedi-ment changes to river sedimentation in Dongjiang River of Huizhou section is about 17%,human activities is the main reason for the rapid incised.