About Mornos Dam

Mornos is the largest water supply reservoir in Greece, located in Phocis in central Greece on the Mornos River. Built in 1979, the earth-fill dam stands 126 metres tall and holds a capacity of 780 million cubic metres — a strategic cornerstone of water infrastructure for the greater Athens metropolitan region. Water from Mornos reaches Athens through the Mornos-Athens Aqueduct, a remarkable engineering feat consisting of 105 kilometres of underground tunnel that carries approximately 40% of Attica's total water supply to the 3.7 million residents of the Athens metropolitan area. The Mornos River catchment drains the Phocis mountains and the eastern slopes of the Pindus range, a zone that receives moderate to heavy winter rainfall, particularly when Atlantic frontal systems track across the eastern Mediterranean. For decades, Mornos functioned as a resilient buffer against drought, routinely reaching full capacity in wet years. However, the intensifying regional water scarcity of recent years has put exceptional pressure on the reservoir. In October 2025, Mornos hit its lowest level in 15 years, dropping to approximately 45% below the previous year's level — a sharp decline that prompted emergency measures across the Attica water system and raised public concern about long-term water security for the capital. In response, the Greek government announced a comprehensive €2.5 billion water investment plan in October 2025 that includes infrastructure improvements, enhanced monitoring systems, and investment in alternative water sources such as desalination. Mornos remains the vital heart of Athens's water supply, and its reservoir levels are scrutinised constantly by water managers, civil engineers, and the broader public — when Mornos is healthy, Attica's water future seems secure; when it runs low, the urgency of regional water planning becomes painfully apparent.