Preliminary exploration of Triftsee
As part of a possible construction of the Trift water reservoir and power plant by the Kraftwerke Oberhasli AG (KWO) based in Innertkirchen, the construction of a new arch dam is planned. In the future, a 20-metre thick and 177-metre high arch dam should be built at approximately the same place where the suspension bridge currently crosses the Trift water. The backed-up water in the lake would amount to about 85 million cubic metres and would de facto be almost the same size as the Grimsel lake reservoir. The water would then be turbined in the new power plant at the top station of the Trift cable car.
As part of the geological investigation, we were commissioned to perform hydraulic packer tests (HPT) and dilatometer tests in 4 boreholes on both sides of the Trift bridge. The aim was to determine rock moduli, hydraulic permeabilities and the hydraulic head.