Measuring debris flow surface velocities through video image processing

This note present a technique based on video image processing for the estimation of surface velocity of debris flows. The method has been developed and tested using video images recorded on the occasion of two debris flows in an instrumented basin of the northern Italian Alps. Debris flows posses a great destructive power and often cause major damages to human infrastructures. Measurements of debris flows characteristics, such as flow height, impact force and velocity may help in the development of countermeasures and warning systems. Development and testing of techniques and methods for measuring these characteristics are of remarkable theoretical and practical importance. Time-lapse photography and electromagnetic Doppler speedometers have already been used for debris flow surface velocity measurements (Suwa et al. 1985). The automated shooting of videos of debris flows and the subsequent use of image processing techniques is here proposed as another method for this type of measurement. Hydroinformatics '98, Copenhagen 24-26 August 1998