Excursion to the Gepatsch Reservoir

In the beginning of September, seven members of the project group visited the Gepatsch Reservoir Study area in the Upper Kaunertal Valley in Tyrol, Austria. The two-day excursion offered insights into the location, topography and landcover of the study area as well as the operating principle of the reservoir and its diversions. 

During those two days, in total three different water intakes were visited: the Verpeil intake (right), the Pitzbach intake (below left) and the Taschachbach (below right). 

1) At the Verpeil intake, which is a part of the diversion “Kaunertal East”, the working principle of the intake setup was explained.
2) At the Pitzbach intake, the group watched the flushing of the sediment from the desilting chamber to the riverbed, after probing the amount of bedload trapped in the desilting chamber.
3) The Taschachbach intake differs from the others: instead of the Tyrolean Weir and the desilting chamber, the coarse sediment is trapped in a basin behind an arch dam.

The first stop at the reservoir was the gate valve tunnel, before we went up to the lake (below, left). After a short stroll over the dam crest, were we could enjoy the view over the reservoir to the glaciers, we went below ground again. The exploration tunnel on the western side of the reservoir partly collapsed some years ago, due to a slow downward movement in the slope above. This sliding movement of the mountain is permanently observed with extensometers installed to the tunnel wall (below, right), in order to detect any accelerations in the sliding process and eventually prevent the initiation of a landslide.

Our next stop took us to the measurement stations of Gepatsch Alm and Weissee (below, left), before we went up to the glaciers, chasing the last sunrays. Overlooking the remaining ice masses and the surrounding mountain slopes we could clearly see the consequences of climate change. Snowless areas and foil covered patches of snow bear witness of the glacier retreat and melting permafrost (below, right). The now uncovered rock faces and fields of loose scree gave us an impression of the sediment amounts which will inevitably be transported to the reservoir in the next decades. This moment demonstrated again the importance of our project and the need for an adapted management strategy based on profound research outcomes.

Many thanks go out to Dr. Johannes Schöber and Franz Eiter from the TIWAG, for taking their time to show us around and providing us with helpful information.

the measurement stations of Gepatsch Alm and Weissee.
Snowless areas and foil covered patches of snow on the glacier