VALIDATION AND IMPROVEMENT OF THE PREDICTION MODEL FOR FLOOD FLOWS AND BED VARIATIONS IN THE GO RIVER CONFLUENCES BASED ON DETAILED OBSERVATIONS OF FLOOD WATER LEVELS AND BED CONDITIONS

Abstract

The Go River confluences are composed of three rivers having a comparable drainage area. The prediction model for flood flows and bed variations in the confluences is needed for investigating the flow and bed variation characteristics and estimating flood water storages by the river confluences. This paper validates the prediction model based on the BVC method against water levels observed at 200- 400m intervals in the confluence during two large floods of different rainfall patterns. Moreover, the cause of the excessive bed scouring around the flow attacking point of the confluence is explored from observations about local bed profiles and conditions around the flow attacking point by using a radio control boat and unmanned submarine. The changes in local bed conditions around complicated flow areas are considered in order to refine the prediction model for flood flows and bed variations.