Autor: Moritz Altmann

In August 2024, the SEHAG Group set up a research camp in the Horlachtal for several days to carry out various surveys at and on Lake Grastal (2500 metres above sea level).

Using sonar technology (sound navigation and ranging), the lake bed of the Grastalsee was surveyed in order to subsequently analyse the underwater topography and the corresponding sediment input. The corresponding technology was installed on a boat, with which the lake bed could be surveyed with centimetre precision in around three hours.

Several channel sections of the Grastal stream above and below the Grastalsee were also surveyed using UAV aerial photography in order to be able to generate digital elevation models. In comparison to earlier models, corresponding changes are to be determined.

Another aim of the camp was to use a rainfall system to simulate various precipitation events on an active debris cone resulting from the LIA glacier forefield of the Grastalferner and reaching into the Grastalsee. For this purpose, different areas with different durations of sedimentation (e.g. between 1997 and 2006 as well as 2021 and 2022) were irrigated. The aim is to investigate the different erosion activity of these younger and older deposits.

Camping ground at Grastalsee.

Survey on the Grastalsee with the sonar-equipped boat.

UAV surveying.

Working on the rainfall system on the debris cone extending into the Grastalsee.

Transport of the work material by helicopter.

In mid-August 2022, a research visit lasting several days was carried out in the Horlachtal in the glacier forefield of the Grastalferner at an altitude of approx. 2900 metres above sea level. Dr Peter Fischer (Department of Soil Geography & Soil Erosion at KU), Moritz Altmann, Jakob Rom, Fabian Fleischer, Eva Schien and Christian Sender were involved in this field campaign as scientific staff. Using a rainfall simulation system and the Erosion3D model, the fluvial erosion patterns of these areas are to be simulated. The aim was therefore to carry out various rainfall simulations on the loose material of the lateral moraine and to take corresponding soil physical parameters, which then have to be analysed in the laboratory for the modelling. The measurements lasted one hour each, with a rainfall intensity of 40 mm per hour, which corresponds to a heavy rainfall event. The area of interest of one square metre was photogrammetrically recorded both before and after the rainfall simulation in order to determine corresponding erosion processes using a DEM of difference (DoD). Using prognosticated precipitation data up to 2050, the future morphodynamics of these areas are to be estimated. The rainfall simulation system was transported to the glacier forefield by helicopter due to its weight and the difficult accessibility of the terrain.

This year’s edition of the DFG calendar focuses on the topic “Digitalisation” and presents 12 DFG-funded projects that use digital processes in their work. The photo submitted by the SEHAG Group as part of a competition represents the month of March.

The image shows a historical photo (from 1924) that has been positioned over a current orthophoto from 2020 and a digital elevation model using photogrammetric methods by determining the exact location of the photographer at that time. The modelled glacier surface from 1924 shows the strong changes of the Gepatschferner in the Kaunertal. The glacier has lost a thickness of about 100 metres at this point. The length of the glacier has decreased by about 2 kilometres since 1924.

The calendar is available for download here.

How can a complicated scientific question be presented in 90 seconds? That was the task for the doctoral students and postdocs of the Catholic University of Eichstätt-Ingolstadt at this year’s Young Researcher Day 2021. This day was aimed at all doctoral students and postdocs at KU with various offers, such as scientific career planning. The task was to present the own research project in a short video. The winners were the three doctoral students Moritz Altmann, Jakob Rom and Fabian Fleischer from the SEHAG subproject Hillslope processes. The video shows the journey from Eichstätt to one of the study areas, the geomorphological slope processes to be studied, the various ways of measuring the earth’s surface, the processing of historical digital elevation models and several successive shaded elevation models that make the dynamics of the slope processes visible. The results show firstly the high geomorphological activity and instability of a recently deglaciated lateral moraine and secondly the acceleration of a rock glacier that we have observed since the 1990s.

The winner’s video can be viewed on the Facebook page of the University of Eichstätt-Ingolstadt.

Airborne Laser Scanning (ALS) is a method of scanning the earth’s surface from the air with a laser beam while recording the reflected signal. From this point cloud, the earth’s surface can be displayed in 3D with a very high degree of accuracy. Using this data, researchers in SEHAG can detect changes in the landscape by comparing these models with older ones. This could be the melting of glaciers, debris flows or vegetation growth. From 22.09.2021 to 24.9.2021, all three valleys of the SEHAG project were flown and recorded. The flight duration amounted to approx. 6-7 hours per valley. The valleys were flown over systematically so that a good data set could be collected for the entire area.