气候变化领域集成服务门户(CCPortal): Shifting Sediment Dynamics in the Coos Bay Estuary in Response to 150 Years of Modification

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DOI	10.1029/2020JC016771
	Shifting Sediment Dynamics in the Coos Bay Estuary in Response to 150 Years of Modification
	Eidam E.F.; Sutherland D.A.; Ralston D.K.; Conroy T.; Dye B.
发表日期	2021
ISSN	21699275
卷号	126 期号:1
英文摘要	Estuaries worldwide have experienced modifications including channel deepening and intertidal reclamation over several centuries, resulting in altered fine sediment routing. Estuaries respond differently based on preexisting geometries, freshwater and sediment supplies, and extents and types of modification. The Coos Bay Estuary in Oregon is a relatively small estuary with complex geometry that has been extensively modified since 1865. A sediment transport model calibrated to modern conditions is used to assess the corresponding changes in sediment dynamics. Over ∼150 years, channel deepening (from ∼6.7 to 11 m), a 12% increase in area, and a 21% increase in volume have led to greater tidal amplitudes, salinity intrusion, and estuarine exchange flow. These changes have reduced current magnitudes, reduced bed stresses, and increased stratification, especially during rainy periods. Historically, fluvially derived sediment was dispersed across broad, deltaic-style flats and through small tidal channels. Now, river water and sediments are diverted into a dredged navigation channel where an estuarine turbidity maximum (ETM) forms, with modeled concentrations >50 mg/L and measured concentrations >100 mg/L during discharge events. This “new” ETM supplies sediment to proximal embayments in the middle estuary and the shallow flats. Overall, sediment trapping during winter (and high river discharges) has increased more than two-fold, owing to increased accommodation space, altered pathways of supply, and altered bed stresses and tidal asymmetries. In contrast to funnel-shaped estuaries with simpler geometries and river-channel transitions, these results highlight the importance of channel routing together with dredging in enhancing sediment retention and shifting pathways of sediment delivery. © 2020. American Geophysical Union. All Rights Reserved.
英文关键词	dredging; estuarine turbidity maximum; estuary; modification; sediment
语种	英语
来源期刊	Journal of Geophysical Research: Oceans
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/186511
作者单位	Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States; Department of Earth Sciences, University of Oregon, Eugene, OR, United States; Woods Hole Oceanographic Institution, Woods Hole, MA, United States; School of Science, University of Waikato, Hamilton, New Zealand; Department of Coastal Systems, Royal Netherlands Institute for Sea Research, AB Den Burg, Netherlands
推荐引用方式 GB/T 7714	Eidam E.F.,Sutherland D.A.,Ralston D.K.,et al. Shifting Sediment Dynamics in the Coos Bay Estuary in Response to 150 Years of Modification[J],2021,126(1).
APA	Eidam E.F.,Sutherland D.A.,Ralston D.K.,Conroy T.,&Dye B..(2021).Shifting Sediment Dynamics in the Coos Bay Estuary in Response to 150 Years of Modification.Journal of Geophysical Research: Oceans,126(1).
MLA	Eidam E.F.,et al."Shifting Sediment Dynamics in the Coos Bay Estuary in Response to 150 Years of Modification".Journal of Geophysical Research: Oceans 126.1(2021).