为确定三峡水库蓄水后荆江河段平滩河槽形态调整特点，提出基于河段尺度的平滩河槽形态参数的计算方法，计算上、下荆江段2002—2013年汛后河段平均的平滩河槽形态参数．结果表明：三峡工程运用后，坝下游河床冲刷加剧，个别河段河势变化剧烈，但总体河势仍基本稳定；尽管局部河段的崩岸现象较为突出，但河段平滩宽度总体变化不大，上、下荆江平均河宽分别为1388及1305m，而河段平滩水深平均增加1．6及1．0m，故荆江河段的平滩面积在持续增加．最后建立河段尺度的平滩河槽形态参数与前期5a平均的汛期水流冲刷强度之间的计算关系，用于预测该河段平滩河槽形态随水沙条件的变化趋势．%In order to determine the recent adjustments in the reach‐scale bankfull channel geometry of the Jingjiang Reach after the operation of the Three Gorges Project (TGP) ,an integrated approach to calculating reach‐scale bankfull channel dimensions was then proposed ,based on the measured section‐scale bankfull geometry in the reach .The bankfull channel dimensions of the Upper and Lower Jingjiang Reaches (UJR and LJR) were calculated using the proposed method and the surveyed post‐flood profiles during the period from 2002 to 2013 .Calculated results indicate that :the channel evolution in the UJR and LJR occurred mainly in the component of bankfull depth after the TGP operation ,although there were significant bank erosion processes in local regions ;the bankfull widths in the UJR and LJR slightly changed ,with the mean values of 1388 and 1305 m ,respectively ;the reach‐scale bankfull depth increased respectively by 1 .6 m in the UJR and 1 .0 m in the LJR ,which caused to the reach‐scale bankfull area to increase gradually . Finally ,empirical relationships for the UJR and LJR were developed between the reach‐scale bankfull channel dimensions and the previous five‐year average fluvial erosion intensity during flood seasons ,w hich can be used to predict the response of the reach‐scale bankfull geometry to the altered flow and sediment regime entering the Jingjiang Reach .
展开▼
