The project consists of the Brantlalm storage pond with associated pumping station including cooling tower system, piste construction measures in areas around the planned storage pond as well as field pipelines to supply existing snow areas. The storage pond, with a capacity of about 155,700 m³, is to be built directly below the Brantlalm in a natural hollow (approx. 1,360 m above sea level). The Brantlalm storage pond will be constructed as a geomembrane-sealed pond. The sealing will be done with 2.5 mm thick AGRU HDPE LINING SYSTEMS and will be protected against damage on both sides with non-woven geotextiles or drain mats according to the state of the art. A 30 cm thick layer of gravel is then applied.
Basin sealing
AGRU supplied a total of 22,830 m² of Microspike+/HighGrip geomembranes and smooth geomembranes to seal the storage pond. The geomembranes are protected from mechanical damage both from the substrate and from the water side by non-woven geotextiles. The plastic geomembrane is connected to the concrete extraction structure by welding it to a HDPE strip inserted in the concrete. The weight of the gravel is transferred to the soil by friction, so that there is no tensile stress on the geomembrane or the protective geotextiles. The protective geotextiles and the AGRU geomembrane are laid into the embedment trench, which is constructed at the height of the top of the dam embankment with an embedding length of at least 2,5 m. The extraction trench runs from the extraction structure to the pumping station and crosses under the ski slope. Since the pond is largely buried in the terrain, the trench is about 16 m deep at its deepest point.