Application of a 3D Laser Scanner in the Assessment of Erosion and Deposition Volumes and Channel Change in a Proglacial River

Previous studies of channel morphological change have often relied upon sparse spatial and temporal data-sets, resulting in a degree of uncertainty in their conclusions. Furthermore, previous methodologies have been unable to quantify small-scale changes in channels composed of sand and fine gravel due to inadequate data density. This study reports the use of a high-resolution 3D laser scanner (LMS-Z210) in the assessment of erosion and deposition volumes in the proglacial zone of Glacier du Ferpècle and Mont Miné, Switzerland. High-resolution (>500 points/m2) data obtained across a 5881 m2 area of braid plain during the early part of the melt-water season permitted digital elevation models (DEMs) of bar surfaces and channels to be produced. The approach negates the need for complex surface interpolation algorithms required in surveys with lower point density, e.g. those obtained from global positioning systems or total stations. Furthermore, the technique has the advantage of being able to cover a large area over a comparatively short time period. Laser scanner returns revealed high vertical precision, ±0·02 m, for dry bar surfaces; however, submerged areas (