The ability to remotely sense bankfull elevations was of particular interest in this study because bankfull mapping depends on topographic indicators. The method proposed here and integrated in a GIS environment combines the hydraulic depth and the flow height for each cross section. The local maxima values indicate a sudden increase in flow width where water spills across the floodplain. Such an approach has been implemented as a GIS tool in the QGIS software, and provides a resulting polygonal map of the bankfull limits. The algorithm was applied on several fluvial reaches in Umbria (central Italy). The source code is available as open source. Preliminary results are presented in Section 4, comparing remotely sensed bankfull limits to those obtained from fields surveys and, more recently, by operator-expert interpretation of aerial orthophotos.
Dealing with the evaluation of the risk connected to the formation of landslide dams at regional scale, it is important to estimate the volume of the depleted material that can reach the riverbed. This information, combined with other elements (river dimensions, valley width, landslide velocity, etc.) allows making predictions on the possibility of river blockage. One of the problems of this approach is the lack of data concerning the shape and position of the sliding surface; this does not permit us to estimate the volume of the landslide material. The IFFI (Inventario dei Fenomeni Franosi in Italia, i.e. Landslide Inventory in Italy) project furnishes information, at different levels of precision, on nearly totality of the landslides existing in Italy. The first level of the IFFI (compiled for all slides) does not contain information on the depth of the sliding surface but contains data regarding the type and the activity of the slope movement. Along with this information the IFFI project also furnishes vector maps containing the boundary of each landslide and the main sliding direction. This paper describes the implementation of an algorithm aimed to define, with an adequate approximation, the 3D geometry of the sliding surface of rotational slides for which, on the basis of geologic maps available at regional scale, some geotechnical parameters can be known or estimated. The work also required the creation of a computer code useful for the 3D analysis of slope stability (3D safety factor) using the simplified Janbu method. All computer code has been created on a GNU-Linux OS and using shell scripting, based on GRASS GIS and R statistical software.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.