气候变化领域集成服务门户(CCPortal): Geomorphic change and biogeomorphic feedbacks in a dryland river: The Little Colorado River, Arizona, USA

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DOI	10.1130/B35047.1
	Geomorphic change and biogeomorphic feedbacks in a dryland river: The Little Colorado River, Arizona, USA
	Dean D.J.; Topping D.J.
发表日期	2019
ISSN	167606
起始页码	1920
结束页码	1942
卷号	131 期号:2021-11-12
英文摘要	The Little Colorado River in Arizona, United States, has undergone substantial geomorphic change since the late 1800s and early 1900s, consisting of sediment accumulation following an earlier period of likely widespread sediment evacuation. We analyzed hydrologic and geomorphic data at different spatial and temporal scales to determine the primary mechanisms responsible for these changes, and to provide context for periods of sediment evacuation and accumulation in other rivers. Peak-flow magnitude has progressively declined since the 1920s despite the occurrence of four alternating periods of high and low total annual flow. Largely coincident with this hydrologic change, the channel has narrowed between 72% and 88% in some reaches since the 1930s, with increases in sinuosity in wide alluvial valleys causing ~21%-32% reductions in channel slope. Dense stands of vegetation colonized, and thus stabilized, the newly deposited floodplains. Although large, long-duration floods caused some channel widening, these floods have been too infrequent to offset the progressive narrowing. Channel narrowing, increases in sinuosity, decreases in slope, and increases in vegetative roughness appear to have caused biogeomorphic feedbacks, thereby exacerbating sediment deposition, disrupting flood conveyance, and contributing to decreases in peak-flow magnitude and in sediment transport. The progressive increase in water development in parts of the basin has also likely contributed to progressive declines in peak flow. These results show that biogeomorphic feedback processes combined with human water development may be as important as, if not more important than, changes in climate in driving hydrologic, geomorphic, and sediment-load change in dryland river environments. © 2019 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184931
作者单位	Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, U.S. Geological Survey, 2255 N. Gemini Drive, Flagstaff, AZ 86001, United States
推荐引用方式 GB/T 7714	Dean D.J.,Topping D.J.. Geomorphic change and biogeomorphic feedbacks in a dryland river: The Little Colorado River, Arizona, USA[J],2019,131(2021-11-12).
APA	Dean D.J.,&Topping D.J..(2019).Geomorphic change and biogeomorphic feedbacks in a dryland river: The Little Colorado River, Arizona, USA.Bulletin of the Geological Society of America,131(2021-11-12).
MLA	Dean D.J.,et al."Geomorphic change and biogeomorphic feedbacks in a dryland river: The Little Colorado River, Arizona, USA".Bulletin of the Geological Society of America 131.2021-11-12(2019).