Aoos/Vjosa River basin


The Aoos/Vjosa River basin is shared by Greece and Albania.

Hydrology and hydrogeology

The 260-km long Aoos/Vjosa River (70 km in Greece) has its source in the Northern Pindos Mountains, and ends in the Adriatic Sea (Mediterranean Sea). The basin has a pronounced mountainous character, with an average elevation of about 885 m a.s.l.

Major transboundary tributaries include the rivers Sarantaporos (870 sq. km) and Voidomatis (384 sq. km).


In Greece, the Aoos Springs Hydroelectric Dam was built on the river.

Of the basin area, 47% is covered with forests. Other forms of land use include: cropland (3.5%), grassland (13.6%), barren (6.4%) and shrubs (29.5%). In Greece, the Aoos is part of the Vikos-Aoos National Park, a Natura 2000 site.

The main pressures result from agricultural activities, animal production and aquaculture.

Pumping lifts have increased locally in Greece, where agricultural activities exert pressure on the Nemechka/Vjosa-Pogoni aquifer. There have been sulphate concentrations of 300-800 mg/l observed in many of the springs. In Albania, minor waste disposal and sewer leakages result in local and moderate pathogen occurrence in the aquifer.

Transboundary cooperation and responses

An agreement concluded between Albania and Greece, which entered into force in 2005, provides for the establishment of a Permanent Greek-Albanian Commission on transboundary freshwater issues. The specific tasks of the Commission include setting joint water-quality objectives and criteria, drafting proposals for relevant measures to achieve the water-quality objectives, and organizing and promoting national networks for water-quality monitoring.

In Greece, implementation of the WFD is in progress. Existing awareness and monitoring need improvement with regard to the aquifer; other measures need to be applied, or are planned, according to WFD requirements. No management measures are yet used in Albania for the aquifer, but a range of measures need to be applied.


The river has a “very good water quality”, which is appropriate for all uses in the basin. Nevertheless, an integrated approach of all environmental, social, economic and technical aspects of water resources management is needed in order to ensure water preservation and environmental integrity in the region.

Local and moderate degradation of ecosystems supported by the Nemechka/Vjosa-Pogoni aquifer has been observed in Albania, and related to issues linked to groundwater quantity. The aquifer, however, is not at risk since population is small and industry is not developed.

The river is known as Aoos in Greece and Vjosa in Albania.

Aoos/Vjosa River Basin Aquifers

Nemechka/Vjosa-Pogoni Aquifer - 136