Potential and limitation of UAV for monitoring subsidence in municipal landfills

Multitemporal topographic measurements are essential for monitoring municipal landfills for economic and security reasons. Accurate evaluation of the landfill volumes still to exploit and the extent of subsidence occurring in the closed plots are critical parameters in landfill management. A municipal landfill located in central Italy has been imaged by a UAV helicopter able to fly in full autonomy in industrial areas. Very high resolution images have been processed by a photogrammetric chain in order to obtain Digital Surface Models and orthorectified images. The resolution of these products was 2.8 cm and the vertical precision of the DSM was at worse 0.5 m, resulting into acceptable errors (better than 5%) on available volume estimations. The DSM has been compared to elevation values produced by conventional theodolite and LIDAR measurements. It is shown that the UAV helicopter system is more flexible and more productive than the two other techniques for a similar precision.