n a small watershed of mountainous areas, it is difficult to calibrate roughness of slope surface, gully and stream, due to laking measured data of natural flow movement. As a result, when flash flood occurs, the flow pridiciton of slope surface, gully and streams disagrees with the acutal case. Based on the fractal theory and the projective covering method, this paper develped a method for measureing directly roughness coefficeint of overland flow, gully and stream flows. In order to verify the method, the bed roughness of mountain rivers was measured by means of 3-D Laser Scanner. Applying the measured data, the roughness of the river was determined using the method proposed in the paper.. It is shown that there is a good agreement with the computed and acutal values.
