We are used to handling complex projects. In this case, our creative, professional, dedicated organisation was certainly put to the test. How to safeguard the transport of 250 tonnes on difficult mountain terrain? A 15% gradient rising to 2,000 metres in height, without dropping, coming to a standstill or sliding backwards? And next, how to dredge without disturbing the running hydroelectric power installation? And where should the 70,000 m3 volume of sand and gravel be stored?
Large amounts of sand, gravel and silt from the mountains are a threat to the reservoirs and turbines of hydroelectric power plants. Turbulence had to be prevented around the suction mouth and the pronounced difference between the water levels had to be taken into account. Spraying the volume of 70,000 m3 on land was not permitted. Therefore, the material had to be stored in an underwater depot, especially provided for this purpose.
The depot was realised in the middle of the lake, a long distance from both the inlet/outlet of the hydroelectric power station and the downstream outlet. A 450 metres floating discharge pipe was used, in combination with a spreading pontoon.