Gully erosion in semi-arid landscapes - monitoring of processes and development

Abstract

The research project MoGul (Large-scale Monitoring of Gully Erosion in Semi-Arid Landscapes) at Trier and Frankfurt University investigates the various types, development and dependencies of gullies as well as geomorphological processes involved in gullying. The investigations are carried out at different sites following a transect from the semi-arid Ebro Basin in Northeast Spain, via the sub-humid Baza and Guadalentín Basins in Southeast Spain and the arid Drâa Valley in South Morocco to the semi-arid Oudalan in Sahelian Burkina Faso. Investigations on short-term gully change are mostly realised using field methods for quantification of linear headcut retreat rates. The lack of image resolutions corresponding to the magnitude and dynamics of gully erosion usually prevents the use of remote sensing data, which in contrast to field measurements allow for the rapid and spatially continuous coverage of a site (Marzolff, 1999; Ries and Marzolff, 2003). The objective of this paper is to present an overview of the first results of the MoGul project on gully monitoring which employs large-scale aerial photography taken from remote-controlled platforms (hot air blimp and kites).