河口河床长历时演变模拟方法探讨--以浙江省飞云江河口为例

基于河口平衡断面河相关系的基本概念建立了潮汐河口地区长历时河床演变模型,根据浙江省飞云江河口的实测水文、泥沙、地形资料对模型的有关参数进行了验证,结果表明无论是水力要素还是河床冲淤变化,计算与实测基本吻合。在验证的基础上,研究了上游建库引水、河道整治等水利工程对飞云江河口河床冲淤的影响。从模型计算结果可以清楚地看到河床对水利工程的响应主要产生两级响应,一级响应发生在水利工程建成初期,河床变形的时间尺度短,二级响应则在一级响应的基础上在长时间及长河段内进行河床再调整,河床变形的时间尺度长,系水利工程及局部河床调整对整个河口系统的影响。

Modeling of long-term fluvial processes in the estuarine zone--Taking Feiyun estuary in Zhejiang Province as an example

A model for the long-term fluvial processes in the estuarine zone has been set up based on hydraulic geometry of river channels.The model has been calibrated by using hydrographic field data as well as data on historical morphological changes of Feiyun estuay.After the calibration,the model has been applied to investigate the impact to the change of flow discharge due to the construction of reservoirs in the upstream and the land-reclamation / bend cut-off project on the Feiyun estuary.The morphological development in the Feiyun estuary appears to be strongly influenced by the upstream flow discharge.A systematic decrease of the flow discharge will cause sedimentation in the estuary.According to the model results the river regulation will cause sedimentation downstream of the project site due to decrease of the tidal volume.In the upstream of the project site sedimentation occurs in the first phase and erosion in case of bend cut-off.The morphological responses of the estuary to both considered cases involve multiple morphological time scales which are corresponding with their spatial length scales.The smallest time scale related to the local changes of the project is as small as only about one year.