Located in Bulgaria, Studena is a crucial structure for supply of potable water and of water for industrial purposes. As such, its uninterrupted operation was mandatory during waterproofing works.
Funded by the World Bank, Studena is an outstanding example of rehabilitation that aimed to prevent critical situations and extend the functional life of the dam. It was carried out with a remarkably sustainable system, including dry and underwater repair.
The largest part of Studena dam was repaired underwater by skilled divers, using innovative tensioning profiles, flat profiles, and point anchors to fasten the waterproofing liner to the dam face.
Since the dam was kept partially full during waterproofing liner installation, the upper portion was installed in the dry (grey surface), while the lower portion was installed underwater (blue surface).
Surface preparation was limited to removal of the unstable shotcrete layer and to the installation of an anti-puncture geotextile at such specific locations.
To keep the geomembrane taut to the surface, tensioning profiles (1, in blue), point anchors (2, in black), batten strips (3, in green), and perimeter seals (4, in red) were used.
Unrolling the geomembrane liner over the anti-puncture geotextile. Using a geosynthetic underlayer allows savings on the costs for underwater works.
Installation of the second component of the tensioning profiles assembly. The configuration of tensioning profiles adopted for this project was developed and patented by Carpi.
