Long-term morphological change in the Ribble Estuary, northwest England
Long-term morphological change in the Ribble Estuary, northwest England
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DOI：
10.1016/s0025-3227(02)00476-0
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发表时间：
2002-09
期刊：
影响因子：
2.9
通讯作者：
D. Wal;K. Pye;A. Neal
中科院分区：
文献类型：
--
作者：
D. Wal;K. Pye;A. Neal
利用水深图、地形测量和遥感数据研究了英格兰西北部Ribble河口的地貌变化。通过对这些数据的分析，编制了泥沙平衡。研究结果揭示了近150年来的净增长趋势。主航道经历了较大的淤积。潮间带较高的部分(盐沼和沙洲)也积累了沉积物，而较低潮间带的沉积量基本保持不变。外口既有净冲刷区，也有净淤积区，潮下泥沙量净增量较小。与主要形态变化有关的充填在19世纪和20世纪初加速，主要是由于人类活动的结果。泥沙淤积增加的触发因素是1810年后堤防的修建和填海，使河口内的潮间带面积、潮流棱柱和流速逐渐减小。此外，在1847年至1910年间修建了一条经过训练的航道以确保航行，并通过疏浚对这条航道进行维护，集中了这条过度加深的航道中的退潮水流，减少了对两岸沙洲的周期性冲刷，增加了沉积。因此，人类活动对该地区地貌发育的影响超过了自然强迫因素的变化。
Morphological change in the Ribble Estuary (northwest England) has been studied, using bathymetric charts, topographical surveys and remote sensing data. A sediment budget has been prepared from the analysis of these data. The results reveal a net accretional trend over the last 150 years. The main channels experienced major infilling. Sediment also accumulated in higher parts of the intertidal zone (salt marshes and sand banks), while the sediment volume in the lower intertidal zone remained essentially the same. There were both zones of net erosion and deposition in the outer estuary, with a small net gain in subtidal sediment volume. Infilling, associated with major morphological change, was accelerated in the nineteenth century and early twentieth century, principally as a result of human activities. The triggering factors for increased sedimentation were embankment construction and reclamation after 1810, which progressively reduced the intertidal area, tidal prism and current velocities within the estuary. Additionally, construction of a trained channel between 1847 and 1910 to secure navigation, and maintenance of this channel by dredging, concentrated the ebb flow in this overdeepened channel and reduced periodic scour over the sand banks on both sides, enhancing sedimentation. Thus, the effects of human activities have outstripped those of changes in natural forcing factors on the morphological development in the area.