Photogrammetric measurement methods of the gully rock wall retreat in Istrian badlands

Abstract

Badlands in Central Istria share a very frequent characteristic with other worldwide badland sites, the rapid erosion rate. Rock wall retreat measurement on such a relief is associated with all types of problems because a certain effort has to be put into the measurement equipment design. Spear vegetation and a few previous studies encouraged the testing of different photogrammetric technologies and data acquisition methods for the determination of the denudation rate in Istrian badlands. The main aim of this paper is the establishment of the most suitable methodological combination for the determination of the badland denudation rate, which is the gully rock wall retreat rate.The photogrammetric approach was tested by measuring and comparing the amount of denudation on the test site, which was established on a gully sidewall. The photogrammetric measurement was used twice within one year. The analysis of the photogrammetric technologies and data acquisition methods focused on the field and laboratory equipment and the accuracy and difference models obtained from the test site measurements. The analysis shows that the combination of digital photogrammetry and fully automatic matching data acquisition provides the most suitable measurement technique of the rock wall retreat in Central Istria badlands and other similar badlands.