The contribution of geomorphological mapping to sediment transfer evaluation in small alpine catchments

Abstract

The assessment of sediment transfer processes is necessary to understand the hydro-geomorphological functioning of small alpine watersheds prone to channelised debris flows because their occurrence often depends on the amount of debris available in the gully systems. Therefore, sediment budgets should be studied through the identification of erosion, transport and deposition processes. Sediment transfer processes were investigated in a small catchment by field measurements and, more specifically, through the application of a process-based geomorphological mapping method. The proposed methodology is based on data directly derived from GIS analysis using high-resolution DEM, field measurements and aerial photograph interpretations. It has been conceived to estimate sediment transfer dynamics, taking into account the role of different sediment stores in the torrential system. The proposed geomorphological mapping methodology is quite innovative in comparison with most legend systems that are not adequate for mapping comprehensively active and complex geomorphological systems such as debris-flow catchments. Maps representing the various sediment storages and their relationships can be used for hydro-geomorphological hazard mitigation.

Evidence for enhanced debris-flow activity in the Northern Calcareous Alps since the 1980s (Plansee, Austria)

“…Detailed mapping of the catchments and fans is a prerequisite for making reliable statements in terms of debris-flow ability, activity and risk assessment (Theler et al, 2010;Hearn and Hart, 2011). Due to the orthophotos, the active parts of the project area could be preliminary identified by field work, although the resolution and contrast of the photos caused some problems.…”

Rainfall simulation and Structure-from-Motion photogrammetry for the analysis of soil water erosion in Mediterranean vineyards

“…The concept of connectivity has increasingly been used in quantitative process-based sediment dynamics research, especially at catchment scales (Ali et al, 2014;Baartman et al, 2013;Bracken and Croke, 2007;Bracken et al, 2015;Brierley et al, 2006;Cavalli et al, 2013;Fryirs et al, 2007;Heckmann and Schwanghart, 2013;Lexartza-Artza and Wainwright, 2011;López-Vicente et al, 2013;Wainwright et al, 2011). Geomorphology has been considered as a major driver on determining sediment connectivity (Heckmann and Schwanghart, 2013;Theler et al, 2010), and geomorphometric indices have increasingly been developed to assess it (Borselli et al, 2008;Cavalli et al, 2013;López-Vicente et al, 2013;Reid et al, 2007;Sougnez et al, 2011). In this study we applied the index of connectivity (IC) as proposed by Cavalli et al (2013) based on the work of Borselli et al (2008), to evaluate the potential effect of sediment connectivity within the plots.…”

Methods for detecting channel bed surface changes in a mountain torrent – experiences from the Dorfbach torrent

“…Theler et al, 2010). Nowadays, various approaches including field work, aerial photo-and/or digital terrain model-based mapping are applied to acquire and present geomorphological forms and processes (Smith et al, 2011).…”