Impact of Hydropower Plant Waters on the Destabilization of Slopes and Causing Landslides to Its Shores

Albania has numerous and biggest dams belonging to the hydroelectric power plant system. This cascade is composed by Fierza, (1978), Komani (1985) and Vau Dejës (1971) hydro power plant. Fierza Hydroelectric Power Plant at higher river flow, has an installed power of 500 MW. The volume of water in its artificial lake is 2.7 billion m3, and lake depth averagely 133 m. The dam has a length on head of 400 meters and height 167 meters. Difference between maximal and minimal levels of surface water in lake was varied over the years from some meters up to 30 or more meters, depending on the annual meteorological conditions.

The exploitation of hydrotechnical work over the last 25 has influenced the modification of their physical-mechanical properties and constructive structure, but also to the lake shore slopes and water reservoirs.

There are observed active landslides in the lakeshores. The most biggest is landslide at Porava village, about 2,5 km from the Fierza dam, etc. These landslises represent a great geological risk for hydropower plants, and Porava village. Walls of the houses are broken in Porava villages.

Results of the complex geological-geophysical-geodesic investigations in above mentioned landslides, and impact of the lake water on slope’s soil and rocks, are presented in the paper.