Channel morphodynamics on a small proglacial braid plain (Fagge River, Gepatschferner, Austria)

Braid plains are important sediment stores in high mountains, particularly in the glacier forefields of Alpine glaciers. Proglacial braid plains receive sediment input from glacial meltwater and proglacial sediment sources like moraines and glacio-fluvial deposits. The channel morphodynamics on the braid plains are strongly related to the sediment transport and flow regime of the proglacial river. This study deals with channel morphodynamics on a small proglacial braid plain in the European Alps. It focuses on two different time scales. Decadal channel planform changes were assessed by remote sensing approaches. The recent channel bed changes were investigated by cross-sectional surveys and particle counts in 2013. This study is part of the DFG/FWF funded interdisciplinary research project PROSA (High-resolution measurements of morphodynamics in rapidly changing PROglacial Systems of the Alps)

A Sediment Budget of the Upper Kaunertal

This chapter presents the sediment budget of the Upper Kaunertal (Ötztal Alps, Austria) for the years 2012–2014 as obtained in the framework of the PROSA (high-resolution measurements of morphodynamics in rapidly changing PROglacial Systems of the Alps) research project. An important methodological basis of this high-mountain sediment budget is the usage of study area-wide LiDAR data (TLS and ALS) of comparatively high temporal and spatial resolution to measure rates of erosion and deposition, and to regionalize/upscale rates at the local scale. After several billion measurement points and data from fieldwork, mapping, and modeling efforts had been processed and evaluated, it was possible to identify and quantify sediment transfer by all relevant processes at the scale of the 62 km2 study area. These processes include rockfall of three different magnitude classes, debris flows, avalanches, creep on talus, fluvial processes (hillslopes and main fluvial system), rock glaciers, and glaciers. After a short presentation of the process-specific methods to obtain catchment-wide rates, we discuss process-specific results and the budget. The sediment budget does not only show the relative importance of the mentioned processes and spatial subunits (proglacial vs. non-proglacial) in the Upper Kaunertal. It also gives insight into the importance of high-magnitude events and the configuration of the sediment transport system

Sediment Connectivity in Proglacial Areas

Sediment connectivity is an emerging property of geomorphic systems and has become a key issue in research on geomorphic processes and sediment cascades. Sediment connectivity represents coupling relationships between system compartments and elementary units, and thus its understanding has important implications for the behaviour of hydro-geomorphic systems. The investigation and characterization of sediment connectivity and its evolution through time are of particular importance in proglacial areas and high-mountain environments since they are subject to intense morphodynamics and frequent changes in their structure and subsequent variations in sediment connectivity. This chapter aims to review the state of the art of sediment connectivity in proglacial and high-mountain environments studies, provides a synopsis of the most widespread landforms in mountain headwater catchments and describes their role with respect to coarse sediment connectivity. In addition, a section of the chapter is dedicated to the description of a recently developed topography-based sediment connectivity index. An example application to two contrasting alpine glacier forefields shows the effectiveness of this index for investigating and interpreting spatial patterns of connectivity in high-mountain catchments. Finally, we sketch avenues for future research regarding sediment connectivity (not only) in proglacial systems

Sediment Transport in Proglacial Rivers

Suspended and bedload transport in mountain rivers are notoriously difficult to monitor and thus to quantify. Even more challenging are proglacial streams that are generally characterized by high flow velocities, high sediment concentrations and transport rates, large and abrupt temporal variability of water discharge and transport rates, as well as by frequent morphological changes. However, the quantification of suspended and bedload transport rates is crucial to understand and predict shortand long-term morphodynamics in such sensitive systems. In this chapter, we present an updated summary on the current knowledge on the monitoring methods and on the observed dynamics of sediment transport in proglacial rivers, including both suspended and bedload fractions