Safeguarding critical infrastructure against landslip risk on a large dam in Albania

The 80m high, 960m long Banja Dam located on the Devoll River in central Albania has a clay core and gravel shoulders. It is founded mainly on Eocene flysch bedrock, which comprises a repetitive sequence of thin beds of mudstone, siltstone and sandstone, with variable dip. Where the beds dip out of the natural topography, slopes are prone to instability.

The Banja Hydropower Project had been started originally in the 1980s but funding difficulties and political upheaval halted construction in the 1990s. At that time, there were also significant technical challenges, with landslips affecting the powerhouse excavation and the headrace tunnel, and with concerns over the stability of the whole hillside above the left abutment.

When construction started again in 2013 there was concern that these historical landslips would be re-activated, and that critical parts of the project would once again be affected by the threat of slope instability. However, during construction the site supervision team took measures to manage these risks and to allow the works to proceed to a successful conclusion. The key components of these measures were regular monitoring of key stability indicators and the construction of a large stabilising berm.