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Tributary Channel Gradation Due to Regulation of Peace River
Abstract: Channel gradation has been investigated in Peace River tributaries following regulation of the mainstem. Comparison of flood period stages in the tributaries and in the mainstem before and after regulation suggests that of order one meter of degradation might occur in the distal reaches of the tributaries. On the other hand, significant sediment delivery from the tributary might attenuate or reverse the effect. Investigations were pursued by examining the history of bar stabilization and vegetation establishment on the lower tributaries and by field surveys of elevation differences between these former bars—now young floodplains—and both older floodplain levels and recent bar surfaces. Dendrodating was undertaken to confirm the time of stabilization of vegetated surfaces. Tributaries within 100 km of the dams exhibit the expected degradation of about one meter near their confluence but, farther downstream, other factors create a more complex picture. These include reestablishment of the coincident timing of high water in both Peace River and the tributaries below the Pine River confluence, significant sediment delivery from some tributaries, including Moberly and Pine Rivers, and the growing influence, more than about 150 km downstream, of the seasonal ice regime in determining high water levels. Smoky River, nearly 400 km downstream and the primary tributary, appears to have aggraded following regulation, likely in consequence of its abundant sediment load. Dendrochronological evidence indicates that young floodplain surfaces have become established near tributary mouths in all decades since regulation.
Tributary Channel Gradation Due to Regulation of Peace River
Abstract: Channel gradation has been investigated in Peace River tributaries following regulation of the mainstem. Comparison of flood period stages in the tributaries and in the mainstem before and after regulation suggests that of order one meter of degradation might occur in the distal reaches of the tributaries. On the other hand, significant sediment delivery from the tributary might attenuate or reverse the effect. Investigations were pursued by examining the history of bar stabilization and vegetation establishment on the lower tributaries and by field surveys of elevation differences between these former bars—now young floodplains—and both older floodplain levels and recent bar surfaces. Dendrodating was undertaken to confirm the time of stabilization of vegetated surfaces. Tributaries within 100 km of the dams exhibit the expected degradation of about one meter near their confluence but, farther downstream, other factors create a more complex picture. These include reestablishment of the coincident timing of high water in both Peace River and the tributaries below the Pine River confluence, significant sediment delivery from some tributaries, including Moberly and Pine Rivers, and the growing influence, more than about 150 km downstream, of the seasonal ice regime in determining high water levels. Smoky River, nearly 400 km downstream and the primary tributary, appears to have aggraded following regulation, likely in consequence of its abundant sediment load. Dendrochronological evidence indicates that young floodplain surfaces have become established near tributary mouths in all decades since regulation.
Tributary Channel Gradation Due to Regulation of Peace River
Church, Michael (editor) / Ayles, Christopher P. (author) / Church, Michael (author)
The Regulation of Peace River ; 67-88
2014-12-03
22 pages
Article/Chapter (Book)
Electronic Resource
English
Downstream Channel Gradation in the Regulated Peace River
| Wiley | 2014
| Wiley | 2014