Abstract
This study reports the resultus of velocity measurements among groynes in River Chikuma.
Two large vortices contribute to flowing in, settling and heaping of suspended particles. The uppside vortex of the impermeable groyne has a characteristic life cycle. It has a negative correlation with fluctuation of a water level.
In time of flood, streamwise vortices released from lowerside of the impermeable groyne rise and flush humus mud on a river bed.
