Effects of catchment characteristics and hydro-meteorological scenarios on sediment connectivity in glacierised catchments

Buter, Anuschka, Heckmann, Tobias, Fillisetti, Lorenzo , Savi, Sara, Mao, Luca, Gems, Bernhard and Comiti, Francesco (2022) Effects of catchment characteristics and hydro-meteorological scenarios on sediment connectivity in glacierised catchments. Geomorphology . p. 108128. ISSN 0169-555X

Full content URL: https://doi.org/10.1016/j.geomorph.2022.108128

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Effects of catchment characteristics and hydro-meteorological scenarios on sediment connectivity in glacierised catchments
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Abstract

In the past decade, sediment connectivity has become a widely recognized characteristic of a geomorphic system. However, the quantification of functional connectivity (i.e. connectivity which arises due to the actual occurrence of sediment transport processes) and its variation over space and time is still a challenge. In this context, this study assesses the effects of expected future phenomena in the context of climate change (i.e. glacier retreat, permafrost degradation or meteorological extreme events) on sediment transport dynamics in a glacierised Alpine basin. The study area is the Sulden river basin (drainage area 130 km2) in the Italian Alps, which is composed of two geomorphologically diverse sub-basins. Based on graph theory, we evaluated the spatio-temporal variations in functional connectivity in these two sub-basins. The graph-object, obtained by manually mapping sediment transport processes between landforms, was adapted to 6 different hydro-meteorological scenarios, which derive from combining base, heatwave and rainstorm conditions with snowmelt and glacier-melt periods. For each scenario and each sub-basin, the sediment transport network and related catchment characteristics were analysed. To compare the effects of the scenarios on functional connectivity, we introduced a connectivity degree, calculated based on the area of the landforms involved in sediment cascades. Results indicate that the area of the basin connected to its outlet in terms of sediment transport might feature a six-fold increase in case of rainstorm conditions compared to “average” meteorological conditions assumed for the base scenario. Furthermore, markedly different effects of climate change on sediment connectivity are expected between the two sub-catchments due to their contrasting morphological and lithological characteristics, in terms of relative importance of rainfall-triggered colluvial processes vs temperature-driven proglacial fluvial dynamics.

Keywords:functional connectivity, graph theory, climate change, geomorphic systems
Subjects:F Physical Sciences > F820 Geomorphology
Divisions:College of Science > School of Geography
ID Code:47885
Deposited On:01 Feb 2022 16:00

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