Limnological study on a newly built drinking water reservoir near Tirana, Albania

Bovilla Lake is a reservoir constructed 12 years ago for supplying the city of Tirana (Albania) mainly with drinking water. It has a surface area of 4.6 km2, a maximum depth of originally 60 m and is monomictic with a stratification period from early spring to end of October. The lake is oligotrophic with low nutrient concentrations (e.g. SRP in spring about 8 μg L − 1) and minor oxygen depletion in the hypolimnion during thermal stagnation. The lake is highly turbid due to severe particle import by several rivers during rain periods. This led to a massive deposition of sediments, lifting the maximum depth to 45 m in 2008. Furthermore, the photic zone reached hardly more than 10 m. Algal species diversity is high; however, diatoms from the genus Cyclotella dominate most of the year both in numbers and biomass. Our study describes for the first time the hydrography and limnology of the Bovilla Reservoir.