河床下切对珠江三角洲峰值水位演变的影响

Effect of channel deepening on the evolution of peak water level in the Pearl River Delta

为研究珠江三角洲峰值水位对采沙造成的河床下切响应过程,通过调和分析方法去除水位时间序列中潮汐节点调制波动的影响,并提出概率密度函数法诊断河网内峰值水位的历史演变趋势。结果表明:三角洲上游峰值水位随着河床的下切而显著降低;河网中腹部地区,峰值水位随着河床的下切出现显著的上升,从而增加了中腹部地区的防洪风险;在下游地区,峰值水位的变化与海平面上升或其他人类活动相关。

To study the response process of peak water level of the Pearl River Delta on the river-bed deepening due to sandmining,the harmonic analysis is used to remove the influence of nodal modulated fluctuation of tide in water level time series,and a method called the probability density function is adopted to explore the evolution trend of water levels in the delta.The results show that the peak water level decreases significantly after the channel deepening in the upstream regions.In the transition regions,the peak water level rises.In the tide-dominated regions or downstream region,changes of peak water level should be related to the sea level rise or other human activities.