整治工程后径流变化对长江口南支分流分沙的影响

Impact of Runoff on Water and Suspended Sediment Division in the Southern Branch of the Yangtze Estuary

基于2010~2016年长江口南支下游南北港、南北槽分流断面的水沙观测资料,根据各分流汊道之间涨潮/落潮/净泄的潮量/输沙量/分流/分沙比及水沙分配不均匀系数,分析了上游径流对南北港、南北槽分流分沙的影响。结果表明,随着流量的增大,南北港与南北槽涨潮水沙量减小、落潮水量增大、落潮输沙量变化不明显、净泄水沙量增大;南港与南槽涨潮分流分沙比上升、落潮分流分沙比下降、净泄分流分沙比上升,北港与北槽涨潮分流分沙比下降、落潮分流分沙比上升、净泄分流分沙比下降;南北港、南北槽分水和分沙的不均匀系数呈现明显的下降趋势。

Based on the measured data of water and sediment discharge in the North/South Passage and North/South Channel at the downstream of the South Branch of the Yangtze Estuary from 2010 to 2016,this paper analyzed the impact of the upstream flow on the water and suspended sediment division according to the tidal volume/sediment transport/di-version/sediment ratio and the asymmetry of water and sediment distribution between each diversion channel.The results show that with the increase of river discharge,the flood and subtidal tidal volume and sediment transport of the North/South Passage and North/South Channel decrease,while the ebb tidal volume increases and the ebb sediment transport has little change.In the South Passage and South Channel,the flood and subtidal divided flow and sediment ratios increa-ses,and the ebb divided flow and sediment ratios decreases,while in the North Passage and North Channel,the flood and subtidal divided flow and sediment ratios decreases,and the ebb divided flow and sediment ratios increases.The asymme-tr y of water and sediment distribution in the North/South Passage and North/South Channel decrease with the increase of river discharge.