Studies of runoff and soil loss have frequently been carried out at plot scale to evaluate the impact of natural conditions as well as land use and management since plots allow to directly isolate these effects from others such as topography, climate and soil properties. However, the small drainage areas associated with this spatial scale imply that only rill and interill erosion processes can usually be described.

The complexities involved in soil losses from concentrated flow (rills, ephemeral and permanent gullies), bedload and suspended load, bank failures, sediment transport and deposition (on hillslopes, and in rivers, reservoirs, etc) require that measurement methodologies and techniques are adapted to provide accurate data of characteristic erosive processes. Acquisition of information about key variables affecting soil erosion, e.g., ground cover or surface roughness, remains challenging at the catchment scale.

This session is intended to bring together analyses of soil loss at catchment scales, where the advantages, difficulties and limitations of techniques will be discussed. We encourage also the presentation of new and innovative techniques for quantification of soil erosion. The interpretation and evaluation of suitable quantitative analyses will improve our understanding of soil loss processes and will enhance decisions and optimization efforts for soil conservation.