A noticeable shift has taken place in recent weeks at Lake Mornos, in south-central mainland Greece, as robust rainfall during over the recent winter season and last month caused a significant increase in water levels. As a result, the long-submerged village of Kallio is once again gradually disappearing beneath the surface of the lake.
This marks a stark contrast to last year, when falling water levels revealed more of Kallio’s remains. The re-emergence of the village, in 2025, had drawn public attention and concern over declining water reserves.
The history of Kallio is closely tied to the water supply of the greater Athens-Piraeus agglomeration (Attica prefecture). In the early 1980s, villagers were forced to abandon the settlement to allow for the construction of the Mornos Dam—an infrastructure project that remains one of the most critical sources of water for Attica today.
Lake Mornos
Reservoir Levels Show Strong Recovery
Recent data indicate a clear improvement in water reserves.
According to figures from the Athens area’s water and sewerage utility (EYDAP), the volume of water in the reservoir stood at 487 million cubic meters on April 6, 2026. By May 6, 2026, it had risen to 525 million cubic meters, marking a substantial increase within just one month, largely attributed to persistent spring rainfall.
The contrast with last year is particularly striking. During the same period in 2025, reserves had dropped to just 319 million cubic meters, raising serious concerns about water sufficiency in Attica.
The impact of drought on Lake Mornos, Greece, one of Athens’ main water reservoirs. /European Union, Copernicus Sentinel-2 imagery
The sharp recovery in water levels is also documented in recent photographs, capturing the reservoir’s renewed state following months of heavy rainfall.
The developments align with broader media reports over the past year, which had highlighted ongoing concerns about drought conditions and water management challenges across Greece prior to this recent turnaround.
