Proglacial erosion rates and processes in a glacierized catchment in the Swiss Alps. Issue 4 (17th November 2017)

• Record Type: Journal Article
• Authors: Delaney, Ian; Bauder, Andreas; Huss, Matthias; Weidmann, Yvo
• Is Part Of: Earth surface processes and landforms. Volume 43:Issue 4(2018)
• Page Start: 765
• Page End: 778
• Publication Date: 2017-11-17
• Subjects: periglacial processes -- glacial sediment -- alpine sediment dynamics -- alpine hydrology -- glacier retreat; Geomorphology -- Periodicals; 551.4
• DOI: 10.1002/esp.4239
• Languages: English
• ISSNs: 0197-9337

Abstract

Abstract: In the Swiss Alps, climatic changes have not only caused glacier retreat, but also likely increased sedimentation downstream of glaciers. This material either originates from below the glacier or from periglacial environments, which are exposed as glaciers retreat, and often consist of easily erodible sediment. Griesgletscher's catchment in the Swiss Alps was examined to quantify erosion in the proglacial area, possible hydrological drivers and contributions of the sub‐ and periglacial sources. Digital elevation models, created from annual aerial photographs, were subtracted to determine annual volume changes in the proglacial area from 1986 to 2014. These data show a strong increase in proglacial erosion in the decade prior to 2012, coincident with increasing proglacial area size. However, examination of the gradient between discharge and sediment evacuation, and modeled sediment transport, could suggest that the proglacial area began to stabilize and sediment supply is limited. The large influx of sediment into the proglacial reservoir, which is roughly 2.5 times greater than the amount of sediment eroded from the proglacial area, demonstrates the importance of subglacial erosion to the catchment's sediment budget. Although far more sediment originates subglacially, erosion rates in the proglacial area are over 50 times greater than the rest of the catchment. In turn, both sub‐ and periglacial processes, in addition to constraining sediment supply, must be considered for assessing future sediment dynamics as glacier area shrinks and proglacial areas grow. © 2017 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd. Abstract : Using DEMs created from a near annual series of aerial photographs between 1986 to 2014, erosion rates and volumes for a proglacial area are determined. Analysis of this data shows that proglacial area erosion likely stabilizes within the study period and comparison of these erosion volumes with bathymetry of the proglacial reservoir suggests 2.5 times more material originates subglacially than from the proglacial area. However, specific proglacial erosion rates are nearly 50 times higher than the catchment as a whole.