Recently, the disasters in urban areas are frequent. If the city in the area of alluvial fans have been developed,along with the fact that heavy rain is increased by global warming,the possibility of landslides not only flood damage increases,and to understand the dynamics of sediment in the river,measures it is essential to take.It is important to capture the behavior of the sediment in the experimental geomorphology scale in actual rivers in order to combine the sediment transport processes and sediment transport model in the reality of the river.Time resolution and spatial resolution of thereto necessary data is not feasible even if the use of the existing satellite remote sensing and aerial photogrammetry,it is essential to the introduction of new technology.Technology to be used in this study,is a method of generating a high-resolution DSM by using the Unmanned Aerial Vehicle(UAV)and SfM-MVS(Structure from Motion-Multi-View Stereo)from around 2013 in Japan.The UAV is allowed to fly at low altitude,and 3D models of the earth's surface by analyzing the image obtained by at least plural photographed on SfM-MVS software.Give Ground Control Points(GCP)to the generated 3D model.Based on it,it is possible to produce orthophotos and Digital Surface Model(DSM).DSM resolution generated from this system is about 10-1~101[cm].As a study of the operational optimization of data acquisition using this technology,Ogura(2015),flight altitude and the UAV,analysis the number of images,depending on the position and the number of ground control points(GCP),the difference,It found that there was a difference,such as the resolution and accuracy.Currently by applying this system,we are monitoring the movement of gravel in Tedorigawa River,Ishikawa Pref.,Japan.This river is a leading Japanese rapids river,and sediment transport is intense because it is the alluvial fan river.Periodically obtaining an image from a UAV,and by the analysis SfM-MVS software,turned into 3D gravel(Figure 1),it based,to produce the DSM resolution 8mm.This was confirmed that it is possible to determine the shape and position of gravel(Fig.2).In the future,DSM periodically acquires,by extracting the difference of DSM,are quantitatively grasp the movement of gravel,to perform a simulation of sediment transport,and aims to contribute to disaster reduction river disaster.