潮汐河道河床活动性时空变化研究——以深圳河为例

Study on temporal and spatial variations of bed activity in tidal rivers:A case of Shenzhen River

潮汐河道的河床冲淤演变关系到河道治理和航道畅通,研究河床活动性及其时空变化特征具有重要意义。选取潮控型河道深圳河作为研究对象,对比分析不同河段洪枯季的水沙关系变化特征,采用马卡维耶夫法计算河道洪枯季的造床流量,并分析涨落潮流和洪水对其影响程度,进一步探讨河床活动性与造床流量的时空变化规律。研究结果表明:潮流是塑造河床形态的主要动力,河道存在一个造床作用基本相当的造床流量群。下段河道深圳河口的造床流量范围介于200~280 m^(3)/s,且洪季造床流量大于枯季;上段河道罗湖的造床流量则为40~60 m^(3)/s,洪枯季造床流量差异较小。河床洪冲枯淤的演变特性与造床流量变化的关系良好,河道上下段河床活动性则呈现明显的空间差异。

The evolution of erosion and deposition in tidal rivers is related to river regulation and smooth navigation,it is of great significance to study the riverbed activity and its variation in temporal and spatial.Taken the Shenzhen River,a typical tidal-dominant river,as an example,the variation characteristics of water and sediment relationship in different river reaches during flood and dry seasons are comparative analyzed,and the dominant discharges in different seasons are calculated by the Makayev method,the impacts of river runoff and tidal current on the dominant discharge are also discussed to further explore the temporal and spatial variations of riverbed activity.The results show that the periodic flood-ebb tidal current plays a substantive role on the riverbed evolution,there exists a cluster of dominant discharge with basically equivalent bed forming effect.The dominant discharge at Shenzhenhekou station in the lower reach ranges from 200 to 280 m^(3)/s,and it is greater in the wet season than that in the dry season.However,the dominant discharge at Luohu station in the upper reach is about 40~60 m^(3)/s,with small difference in different seasons.The characteristics of scouring in flood season and silting in dry season are in good relationship with the variation of dominant discharge,the riverbed activity in the upper and lower reaches of the Shenzhen River presents significant spatial differences.