Underwater maintenance works in the Gepatsch reservoir

As a result of sedimentation problems in the Gepatsch reservoir, a special structure was created to enable inspection and maintenance work to be carried out in the headrace and bottom outlet tunnels upstream of their locking devices, without the need to draw down the reservoir. Steel guide frames with sliding stoplogs were installed in front of the bottom outlet intake structure and the lower headrace intake at a depth of about 110 m by divers, using a saturation system. Innovative design features of this project are described here.