3:30 PM - 3:45 PM
[ACG42-07] Sediment budget analysis and geomorphological evolution in alluvial river – Case study in the lower Yodo River –
★Invited Papers
Keywords:Alluvial river, Sediment budget, Geomorphological evolution
This study starts with presenting field evidences that illustrate the occurrence of significant bank erosion in the lower section of the Yodo River. It then demonstrates that the resulting escarpments were not mere local adjustments, but are an indicator as to how extensively the Yodo River has undergone appreciable amounts of channel erosion over the entire 70km-long section. The datasets on which the discussion is based include: the cross-channel topographical data (200m intervals along the river course) in first half of 1970s, early 1990s and late 2000s made available from the Yodogawa Office, MLIT. A careful geomorphological analysis of the datasets in terms of GIS, permitted the determination of tempo-spatial changes of areal sediment storage in the Uji River, a tributary of Yodo River.
When integrated over the entire river course, the overall volume of sediment loss due to erosion proved to amount to 41.3 ×104 tons a year in the period from first half of 1970s up to late 2000s. A discussion is made to identifying its practical implications for future riverine management. Furthermore, a discussion is made of the linkage between the extent of the channel erosion and the depositional environments of the sediment that constitutes the boundary of the river channel.
When integrated over the entire river course, the overall volume of sediment loss due to erosion proved to amount to 41.3 ×104 tons a year in the period from first half of 1970s up to late 2000s. A discussion is made to identifying its practical implications for future riverine management. Furthermore, a discussion is made of the linkage between the extent of the channel erosion and the depositional environments of the sediment that constitutes the boundary of the river channel.