Abstract
Flood-channel excavation is not only countermeasure against river flooding but also effective operation for floodplain restoration. In the Ibi River, 14 excavation sites varying in relative height to water level were investigated to examine process of microtopgraphy formation after the flood-channel excavation. Deposit rate was lower in the sites with lower relative height. The proportion of water area (i.e. floodplain waterbodies) in the excavation sites was 10-20%. Sediment profiles were also surveyed at 10 locations in two representative sites and were elaborated in relation to microtopographies that were classified into four types: natural-levee, low land behind natural-levee and isolated and connected waterbodies. Moreover, the microtopography formation process and factors were estimated based on the results of the field survey.
