干旱区生态环境知识资源中心(Arid): The hydromorphological effects of dams in an extreme desert environment

Arid

DOI	10.1016/j.geomorph.2024.109124
	The hydromorphological effects of dams in an extreme desert environment - The Fish River Canyon, Namibia
	Grodek, T.; Cloete, G.; Vazquez-Tarrio, D.; Benito, G.
通讯作者	Grodek, T
来源期刊	GEOMORPHOLOGY
ISSN	0169-555X
EISSN	1872-695X
出版年	2024
卷号	453
英文摘要	Arid ecohydrology relies on sporadic rainfall and flooding to sustain linear river oases, crucial for supporting flora and fauna during the long dry season and drought years. Growing water demands have led to large reservoir constructions, severely impacting the fragile arid ecosystems. We analyse the hydro-geomorphological impacts of the large Neckartal Dam (completed in 2019) on the Fish River oasis based on existing dams, regional studies, field surveys, hydrological data, and modelling. The Neckartal Dam, along with three smaller dams, impounds 80 % of the desert oasis basin (1235 Mm(3), 55,870 km(2)), exceeding the average annual runoff threefold. A gradient of dam-induced changes was identified, varying with distance from the dam wall. Immediate downstream, hydromorphological impacts include channel narrowing (similar to 15 %) and reduce mean annual sediment yield (similar to 20 %). Also, water distribution losses create chronic low flows, favour for invasive flora and fauna to spread, significantly disrupting the pristine nature of the desert ecosystem. This phenomenon has been observed over a 70 km stretch below the Hardap Dam. This situation is irreversible, as the invasive flora can withstand even large floods. As the distance increases, the dam suppresses low to moderate annual floods and prolongs droughts from months to years or even decades. Based on our flood routing model, only the largest floods (recurrence interval, RI >25 years) can exceed the dam storage, continue downstream, transport sediment and maintain the pool-bar morphology along 245 km of the oasis. The lack of significant flows between major floods means that sediment from smaller, lower arid basins accumulates in the Fish River valley, filling pools and further reducing water availability during dry periods. The Neckartal Dam's impact assessment demonstrates potential changes in arid river systems globally.
英文关键词	Large dam impact on fluvial geomorphology Sediment transport Desert river linear oasis Desert river ecohydrology Fish River, Namibia Neckartal Dam Dam flood-routing model
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:001222435000001
WOS关键词	CHANNEL CAPACITY DOWNSTREAM ; LOWER KUISEB RIVER ; COLORADO RIVER ; ADJUSTMENT ; RECHARGE ; CLOSURE ; FLOODS ; IMPACT
WOS类目	Geography, Physical ; Geosciences, Multidisciplinary
WOS研究方向	Physical Geography ; Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/403944
推荐引用方式 GB/T 7714	Grodek, T.,Cloete, G.,Vazquez-Tarrio, D.,et al. The hydromorphological effects of dams in an extreme desert environment - The Fish River Canyon, Namibia[J],2024,453.
APA	Grodek, T.,Cloete, G.,Vazquez-Tarrio, D.,&Benito, G..(2024).The hydromorphological effects of dams in an extreme desert environment - The Fish River Canyon, Namibia.GEOMORPHOLOGY,453.
MLA	Grodek, T.,et al."The hydromorphological effects of dams in an extreme desert environment - The Fish River Canyon, Namibia".GEOMORPHOLOGY 453(2024).