A €1.21 million project is moving forward to fully restore extensive damage and subsidence in the underground channel of the Ilissos River in Kallithea, southern Athens.
A contract for the project was signed by Attica Regional Governor Nikos Hardalias, launching the long-awaited restoration of a serious infrastructure problem that has remained unresolved for more than eight years.
The project has a total budget of €1,209,500, excluding 24% VAT, and includes interventions at two separate points of the underground river channel, as well as the full restoration of a collapsed section of the road surface in an outdoor parking area next to the Tavros ISAP suburban railway station.
Athens – Torrential Rain // Ilissos River. (Eurokinissi)
Damage first identified in 2018
The problem became apparent in May 2018, when the ground subsided in the outdoor parking area alongside Panagi Tsaldari Street.
The subsidence revealed extensive damage to the covered section of the Ilissos channel. Part of the channel’s stone retaining wall had collapsed, while a significant section of the channel bed had been eroded.
Technical investigations in the area also identified an underground stormwater pipe and water infiltration that had further aggravated the condition of the structure.
The findings confirmed the need for a comprehensive intervention to repair the damage and prevent further deterioration.
Work to cover at least 120 meters
The first intervention area, designated as Site A, is located beneath the outdoor parking area.
Work will cover at least 60 meters and will include repairing the subsided channel bed and rebuilding the section of the stone retaining wall that has partially collapsed. The damaged section of the parking area’s road surface will also be fully restored.
The second intervention area, Site B, is located about 850 meters downstream from the first site, in the direction of the river’s flow.
There, workers will repair subsidence affecting at least another 60 meters of the channel bed.
Together, the two interventions will cover at least 120 meters of the underground Ilissos channel.
Flood protection and infrastructure safety
According to the project plans, the restoration is expected to strengthen flood protection and the structural stability of the underground channel.
Repairing the channel bed and rebuilding the retaining wall will help maintain the smooth flow of water while reducing the risk of further erosion, undermining and new subsidence.
The project is also intended to better protect urban infrastructure and nearby utility networks from potential future damage.
The damaged road surface will be restored as well, allowing the parking area to reopen as a safe and fully functional facility in a densely populated part of Kallithea with significant daily demand.
Hardalias: Infrastructure safety is a daily responsibility
Following the signing of the contract, Hardalias said the project would provide a permanent solution to an infrastructure problem that had remained unresolved since 2018 and had directly affected public-space safety and residents’ daily lives.
He emphasized the importance of maintaining underground infrastructure, saying it requires systematic monitoring, timely maintenance and decisive intervention when damage or subsidence is identified.
“For us at the Attica Regional Government, maintaining and protecting critical infrastructure is a daily responsibility to citizens,” Hardalias said. He added that available resources should produce measurable results for the safety and quality of life of residents.
He also said the regional government would closely monitor the progress of the work until the underground section of the Ilissos was fully restored and the parking area could be safely returned to residents and visitors.
Kallithea mayor welcomes long-awaited project
Kallithea Mayor Kostas Askounis, who attended the contract-signing ceremony, described the project as a long-standing request of the municipality that was now becoming a reality.
He said the work would restore safety in a particularly affected part of the city, protect nearby infrastructure and allow the safe reopening of the parking area next to the ISAP station.
Askounis thanked Hardalias for his contribution to advancing the project and said the municipality would work closely with the Attica Regional Government to ensure the construction proceeds according to plan and the area is returned to the public in a safe and fully functional condition.
The contract-signing ceremony was also attended by South Athens Vice Regional Deputy Governor Gina Adamopoulou, Director General for Development Planning of Projects and Infrastructure Miltiadis Kyrkos, and Chara Bitzileki, supervisor of the Attica Regional Government’s Technical Works Directorate.
