Glacier retreat and long-term changes in land cover and fluvial morphology

The project is designed to identify the consequences of glacier retreat on land cover and downstream fluvial morphology over the long term. It is based on orthophotos from the last 70 years, but extends the temporal scale back to around 1800 CE. The GIS-based reconstruction of the historical land cover changes and of the fluvial system at different points in time within the last approx. 200 years will be conducted in analogy to the “regressive-iterative reconstruction method” developed by Hohensinner et al. (2013). In the present project, this methodological approach will be evaluated for the LTER study site at the glacier Jamtalferner and the downstream, approx. 12 km long River Jambach in Tyrol. For each point in time the areal extents of the glacier, (proglacial) channel network, debris depositions, natural vegetation cover and human modified land cover will be localized and quantified. The focus is on the configuration of the fluvial system of the Jambach – i.e., whether significant changes in morphological river type (straight, braiding, sinuous, oscillating, meandering, etc.), channel width, length and sinuosity of the river’s course can be detected. Alterations of the historical channel patterns reveal changes in the external framework conditions, i.e., an increase or reduction in debris/sediment supply or bankfull discharge. Moreover, the simultaneously ascertained changes in land cover will also allow for the identification of the potential causes of the historical fluvial modifications.