DOI: 10.1002/esp.4717
论文题名: Tributary-junction fans as buffers in the sediment cascade: a multi-decadal study
作者: Leenman A. ; Tunnicliffe J.
刊名: Earth Surface Processes and Landforms
ISSN: 1979337
出版年: 2020
卷: 45, 期: 2 语种: 英语
英文关键词: Alluvial fans
; Fluvial geomorphology
; Sediment routing
; Tributary junctions
Scopus关键词: Deforestation
; Sediments
; Storms
; Alluvial fans
; Basin characteristics
; Fluvial geomorphology
; Fluvial transport
; Global standards
; Sediment accumulation
; Sediment cascades
; Sediment-routing
; Rivers
; alluvial fan
; basin evolution
; deforestation
; environmental disturbance
; fluvial geomorphology
; geoaccumulation
; tributary
; Atlantic Coast [North America]
; Atlantic Coast [United States]
; New Zealand
; United States
英文摘要: Alluvial fans at tributary junctions modulate sediment flux through river networks, by buffering the mainstem channel from disturbance in the tributaries. Buffering occurs through the storage (and release) of sediment in fans. Here, we use an extensive historic dataset to characterise the ways in which fan buffering can change as sediment supply varies. In New Zealand's East Coast region, sediment supply and fluvial transport are prolific by global standards. We reconstruct how tributary-junction fans in this region have responded to sediment generated by deforestation and extreme storms. The dynamics of five fans along the Tapuaeroa River are examined for the period 1939–2015. In response to major sediment loading, fans aggraded by up to 12 m and prograded by up to 170 m. Net sediment accumulation ranged from near zero to 1.5×106 m3. Fan size, gradient, sediment storage and buffering were influenced by both upstream and downstream controls. Key upstream (tributary) influences were sediment supply and stream power; downstream (mainstem) influences included distal confinement and, importantly, the nature of fan interaction with the mainstem, which aggraded by up to 6 m. The fans' ability to buffer the Tapuaeroa River from change in the tributaries was largely governed by this downstream interaction: as the mainstem aggraded, it increasingly curtailed fan progradation, thus limiting buffering. Previous studies of tributary-junction fans have related fan morphometry to basin characteristics. However, we find that fan slope and area can vary considerably at decadal, annual or even monthly timescales. Consequently, we suggest that such studies could benefit by examining regional histories of disturbance. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/159736
Appears in Collections: 气候变化与战略
There are no files associated with this item.
作者单位: School of Environment, University of Auckland, Auckland, New Zealand; Department of Geography, University of British Columbia, Vancouver, BC, Canada
Recommended Citation:
Leenman A.,Tunnicliffe J.. Tributary-junction fans as buffers in the sediment cascade: a multi-decadal study[J]. Earth Surface Processes and Landforms,2020-01-01,45(2)