THE EFFECT OF CONFIGURATION ON FLOOD FLOW IN STREAM VALLEY

The flood disaster in a stream valley is discussed with experimental results by water surface flow visualization and water level measurement. From a field survey, it is found that the magnitude of damage is dependent on valley width, which implies the change of flood flow depth on the alluvial plain, and river width at the bend apex. As experimental results, the magnitudes of water surface velocity and divergence around the apex are large for deep condition on the flood plain and narrow channel width at the bend apex, implying that significant erosion can occur around a bend. Thus it is important to understand the effect of configuration on flood flows and appropriate river width at the bend apex to reduce flood damages in a stream valley.