About Iskar Dam

Iskar Reservoir is the largest dam in Bulgaria and the primary source of drinking water for the capital city Sofia, supplying approximately 1.2 million residents. Located in the western Balkan Mountains within the Iskar gorge, the dam was completed in 1954 and impounds the Iskar River, the longest river that rises and flows entirely within Bulgaria. With a total capacity of 655.3 MCM, Iskar Reservoir has shaped the water security of the Sofia metropolitan area for seven decades. The reservoir stretches for nearly 20 kilometres through a dramatic canyon and is fed by snowmelt from the Rila and Vitosha mountain ranges, giving it a reliable annual recharge cycle. The Iskar cascade below the dam includes several hydroelectric power stations that contribute to Bulgaria's electricity grid. The reservoir is also an important habitat for migrating waterbirds and supports recreational fishing. The dam structure is a concrete gravity type standing 74 metres high. Water managers prioritise domestic supply above all other uses, with irrigation and hydropower generation allocated from surplus storage. Sofia's water utility SOFIYSKA VODA monitors Iskar levels daily, and the reservoir's fill percentage is closely watched during summer droughts as an indicator of the city's water security outlook for the coming months.