Large-scale coastal change in the Columbia River littoral cell: An overview
Large-scale coastal change in the Columbia River littoral cell: An overview
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DOI：
10.1016/j.margeo.2010.02.007
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发表时间：
2010-08
期刊：
影响因子：
2.9
通讯作者：
G. Gelfenbaum;G. Kaminsky
中科院分区：
文献类型：
--
作者：
G. Gelfenbaum;G. Kaminsky
介绍了哥伦比亚河沿岸的单元（CRLC）的大尺度海岸变化。沿岸的单元覆盖了华盛顿西南部和俄勒冈州西北部海岸的165公里，由宽阔的低坡耗散海滩、宽阔的海岸沙丘和屏障平原、三个大河口组成，并以岩石岬为界。海滩和内陆架由来自哥伦比亚河的细粒沙组成，并暴露于高能冬季波浪气候。在整个全新世，CRLC经历了海岸线变化趋势的大幅波动，响应各种海岸变化驱动因素，包括海平面上升的变化率，罕见但灾难性的同震沉降事件，大量的区域沉积物供应，年际气候波动（厄尔尼诺周期），季节性变化的波浪气候和许多人为影响。人类活动对CRLC的影响包括在哥伦比亚河流域建造200多座大坝，疏浚航道，将沙子移到高地和离岸深水区，以及在哥伦比亚河和格雷港入口处建造大型入口码头。在过去的一百年里，这些世纪末建造的大型入口码头一直是大多数沿岸的单元沿海变化的主要驱动力。目前，沿岸的单元中的一些海滩正在受到侵蚀，这是由于a）封闭入口的落潮射流将先前较大的浅水落潮三角洲推向离岸深水，以及B）波浪分散近岸三角洲侧翼，最初向岸上，然后沿海岸远离码头。本综述描述了1）在多个时间和空间尺度上对沿岸的单元的沉积动力学进行全系统理解的动机，2）西南华盛顿海岸侵蚀研究的形成和方法，以及3）对该特刊论文的介绍。
This overview introduces large-scale coastal change in the Columbia River littoral cell (CRLC). Covering 165km of the southwest Washington and northwest Oregon coasts, the littoral cell is made up of wide low-sloping dissipative beaches, broad coastal dunes and barrier plains, three large estuaries, and is bounded by rocky headlands. The beaches and inner shelf are composed of fine-grained sand from the Columbia River and are exposed to a high-energy winter wave climate. Throughout the Holocene, the CRLC has undergone large fluctuations in shoreline change trends, responding to a variety of coastal change drivers, including changing rates of sea-level rise, infrequent, yet catastrophic, co-seismic subsidence events, a large regional sediment supply, inter-annual climatic fluctuations (El Niño cycles), seasonally varying wave climate, and numerous anthropogenic influences. Human influences on the CRLC include construction of over 200 dams in the Columbia River drainage basin, dredging of navigation channels removing sand to upland sites and offshore deep-water sites, and construction of large inlet jetties at the entrances to the Columbia River and Grays Harbor. The construction of these massive entrance jetties at the end of the 19th century has been the dominant driver of coastal change through most of the littoral cell over the last hundred years. Presently, some beaches in the littoral cell are eroding in response to nearshore sediment deficits resulting from a) ebb-jets of the confined entrances pushing the previously large, shallow ebb-tidal deltas offshore into deeper water, and b) waves dispersing the nearshore delta flanks initially onshore and then alongshore away from the jetties. This overview describes 1) the motivation for developing a system-wide understanding of sediment dynamics in the littoral cell at multiple time and space scales, 2) the formation and approach of the Southwest Washington Coastal Erosion Study, and 3) an introduction to the papers in this special issue.