清水沟流路河口河道主槽冲淤调整及其对水沙条件的响应

SCOUR-FILL ADJUSTMENT OF THE TRUNK OF QINGSHUIGOU CHANNEL AND THE RESPONCE TO FLOW-SAND REGIME

  • 摘要: 通过分析黄河口利津水文站1950-2006年水文、泥沙资料和1976-2006年利津至清7河段固定断面资料,结果表明:清水沟流路行水以来,进入河口区水沙通量总体偏低,来水来沙更集中于汛期,尤以泥沙量为甚,水沙搭配也较以前畸高;河口河道主槽淤积明显,且绝大部分淤积在CS7-清7河段,全河口段共淤积泥沙量为3.15亿m3,其中汛期淤积1.12亿m3,非汛期淤积2.03亿m3;河口河道主槽冲淤过程可分为4个阶段,即汛期强烈淤积、非汛期适度调整(1976-1979年),汛期强烈冲刷、非汛期强烈淤积(1981-1985年),汛期与非汛期持续淤积(1986-1996年),以及汛期冲刷、非汛期淤积(1996-2006年),并有2年期的"记忆"效应;河口河道主槽冲淤量与径流量、输沙量和来沙系数存在部分线性或秩相关,但来水来沙数量和水沙搭配参数并非为影响主槽冲淤的主要决定性因素,水沙过程、河床边界条件和人类活动干预等因素在主槽冲淤变化过程中起着更为重要的作用。

     

    Abstract: Daily observation data on river flow and sediment charges at Lijin hydrological station during 1950-2006,and fixed cross-section measurement data between Lijin and Qing 7 from 1976 to 2006 were employed to address the erosion/deposition pattern of the mouth channels of the Huanghe River and its relationship with water and sediment inputs since the Qingshuigou course was established.Results show that since then the incoming flow and sediment charges have remained in a lower level,with more sediment discharge concentrated in flooding season.Meantime,the accumulative dopositional amount in the main channel between Lijin and Qing 7 comes up to 3.15×108m3,of which 1.11×108m3 occur in flood season and 2.03×108m3 in dry season,and most sediment load deposit in the reach between CS7 and Qing 7.The scour and fill process of the mouth channel is roughly experienced four stages,i.e.strong fill in flood season and slight adjustment in dry season(1976-1979),strong scour in flood season and strong fill in dry season(1981-1985),continuous fill in whole year(1986-1996),and scour in flood season and fill in dry season(1996-2006).There are two-year cycle of memory effects.Sediment amount of scour or fill in the mouth channel partially exhibited linear and/or rank correlation with runoff,sediment discharge and incoming sediment coefficient. However,water and sediment flux and water/sediment coefficients are not the major determinating foctor of the scour/fill pattern at the main channel.Flow and sedimentation process,riverbed boundary conditions and human activities play vital roles in scouring and filling process of the mouth channels.

     

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