EYDAP S.A has undertaken a group of projects that are co-financed by the European Union Cohesion Fund. These projects deal with the preservation and augmentation of the water conveyed via the external aqueduct system from the 4 raw water reservoirs (Mornos, Yliki, Marathon, Evinos) to the 4 Water Treatment Plants.

Furthermore, these projects aim for the reciprocity of the water aqueducts in order to ensure the Attica region with an uninterrupted water supply, under any conditions.
This goal is realized by the creation of a ring of aqueducts – called the Parnitha Ring – around the mountains of Kitherona and Parnitha.
That way, the access to the Water Treatment Plants from the West (Aspropirgos WTP and Acharnon WTP) as well as from the East (Marathona – Chelidonou – Galatsi and Marathonas – Chelidonou – Acharnon aqueducts) is achieved.

The main supply source of the Water Treatment Plants is the Mornos Aqueduct that has begins at the man-made reservoir of Mornos (200 km away from Athens). Starting from the Mornos reservoir, water is transferred to the WTPs through a system of open or closed canals.

The projects that have been completed along the Mornos Aqueduct up to the Kitheronas region (150 km of length) are presented below:

1. Taxiarchon Tunnel Project: Construction of the Taxiarchon Tunnel (550 m of length) in order to bypass an unsafe area of the Mornos Aqueduct.
2. Static reinforcement of various sections of the open canal (40 km of length) at:
 Chrisso

• Delfi 
• Kiriaki - Elikonas
• Thisvi - Ellopia

3. Thiva Canal Project: Reduction of leakages by relining sections of the Thiva canal with a special PVC membrane (14 km of length).

Projects currently in progress:

1. Connecting Aqueduct of Mornos - Yliki - Kremada - Dafnoula: The reinforcement (supply augmentation) of the aqueduct system conveying water from the Yliki aqueduct to the Mornos system and the securing of the interconnecting aqueduct for the gravity supply of the Yliki system from the Mornos Aqueduct.
2. Supply increase of Mornos Aqueduct downstream of the Kitheronas tunnel (installation of a new Φ 2000 steel pipeline and the structural reinforcement and coverage of the existing canal).
3. Installation of new Φ1700 steel pipeline (4 km in length) between Chelidonou and the Galatsi WTP and installation of new Φ1700 pipeline (6,5 klm of length) between Chelidonou and the Acharnon WTP to ensure the carrying capacity to all the WTP.
4. Operational improvements of the Mornos Reservoir Management System of water collection and transfer.
5. Upgrading of the three Water Treatment Plants for their improved operation.
6. Installation of 5 self-cleaning screening devices for improved water quality.
7. Improvement of the water intake works of the Marathon Reservoir at the entrance of the Bogiati tunnel.