Sediment Flux and Bed Level Measurements from a Macro Tidal Mudflat
Sediment Flux and Bed Level Measurements from a Macro Tidal Mudflat
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DOI：
10.1006/ecss.1999.0525
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发表时间：
1999-11
影响因子：
2.8
通讯作者：
M. Christie;K. Dyer;P. Turner
中科院分区：
文献类型：
--
作者：
M. Christie;K. Dyer;P. Turner
本文详细分析了英国亨伯河口Spurn湾一年来悬沙通量和床面的变化。悬沙浓度与流速相关，波浪活动主导侵蚀过程，并支配剩余潮通量。向岸流动和几毫米沉积物的逐渐堆积是平静水动力条件的典型特征。相比之下，大浪造成几厘米厚的沉积物被侵蚀，阻止了在静水上的沉积，产生了大量的向海迁移。这些被侵蚀的物质在平静的情况下可以在短短几天内得到补充。泥滩水位不断变化，以便与波浪气候、潮汐周期、河流径流和季节效应达到某种平衡。当模态强迫条件出现显著偏差时，泥滩形态迅速出现大的差异。这些相对短期的事件往往会随时间而互相抵消，而床面变化的净季节性变化约为几毫米。多元回归分析被用来产生经验表达式预测剩余泥沙通量和床面容易观察到的环境参数。结果量化了影响剩余潮汐通量的主要物理过程，并建立了一些特定地点的关系，为更一般的通量预测提供了基础。
A detailed analysis is presented of the variations in suspended sediment flux and bed level, measured for one year in the Spurn Bight, Humber Estuary (U.K.). Suspended sediment concentrations were correlated to flow speed, and wave activity dominated the erosion processes and governed the residual tidal flux. An onshore flux and gradual accretion of a few millimetres of sediment were typical of calm hydrodynamic conditions. In contrast, large waves caused the erosion of several centimetres of sediment and prevented deposition over slack water, producing significant seaward transport. This eroded material could be replenished in just a few days under calm conditions. The mudflat level was continually changing in order to reach some equilibrium in balance with the wave climate, tidal cycle, river runoff and seasonal effects. Large differences in the mudflat morphology rapidly occurred when there were significant deviations from the modal forcing conditions. These relatively short term events tended to cancel out with time, and the net seasonal changes in bed level variations were about a few millimetres. Multiple regression analysis was used to produce empirical expressions predicting the residual sediment flux and bed level from readily observable environmental parameters. The results quantified the dominant physical processes affecting the residual tidal flux and established some site-specific relationships that provide a basis for more general flux predictions.