Educate logo-RGB_AZ.jpg

postgraduate programme in Water Resources and Environmental Management












See Achelous river dams in Google maps:,21.626587&spn=1.792897,3.521118&z=8





From the decade of 60s the Public Power Corporation (PPC-ΔΕΗ), was seeking for a place to settle a hydroelectricity plant. PPC had chosen the location “Logga Romosiou” where the two mountains converge. The investigations begun after 1970 but the artificial lake that was created covered the town of Mesochora which was not foreseen. Thus the idea for a small hydroelectricity plant was evolved to a large reservoir of 150 m in the context of the biggest artificial work in history of Greece, the Achelous diversion.   

General information


Location: Trikala prefecture

Dam type: Concrete Faced Rockfill (CFRD)

Dam Height: 150 m

Crest Length: 340 m

Dam Volume: 5 x106 m3

Reservoir capacity: 358 x106 m3

Reservoir surface: 7.8 x106 m2

Use: H (Hydropower)

Power: 160 MW

Energy: 372 GWh/yr

Owner: Public Power Corporation (PPC)

Year of operation: 1995



SYKIA DAM               


Sykia’s dam is part of the complex artificial work of Achelous river diversion. The dam works has not been completed. The works for Achelous diversion are suspended temporarily by decision of Supreme Administrative Court. The works has been suspended three times until now (1994, 2000 and 2005). The Court will decide again after the answers upon questions that have posed to The Court of Justice of European Union. The Achelous diversion has been probably the most controversial artificial work in history of Greece.

General information


Location: Trikala, Karditsa and Arta prefectures

Dam type: Earthfill (TE)

Dam Height: 170 m

Crest Length: 397 m

Dam Volume: 12.4 x106 m3

Reservoir capacity: 502 x106 m3

Reservoir surface: 12.8 x106 m2

Use: HI (Hydropower, Irrigation, Achelous Diversion)

Power: 160 MW

Installed Power: 126.5  MW

Owner: Hellenic Ministry for the Environment, Physical Planning & Public Works

Beginning of construction: 1996 (temporarily stopped)




The dam of Kremasta is located 3 klm away from the join point of river Tavropos and Agrafioti with river Achelous. Geographically the artificial lake belong to the prefectures of Evritania and Aitoloakarnanias while the hydroelectricity works (dam, station, village etc) belongs to Aitoloakarnania. The drainage basin is 3,750 km2


General information


Location: Evritania & Aitoloakarnania prefectures

Dam type: earthfill (TE)

Dam Height: 165 m

Crest Length: 456 m

Dam Volume: 8.1 x106 m3

Reservoir capacity: 3,800 x106 m3

Reservoir surface: 80,6 x106 m2

Use: H (Hydropower)

Power: 437.2 MW

Energy: 848 GWh/yr

Owner: Public Power Corporation (PPC)

Year of operation: 1965





§         BROCHURE

§         VIDEO 



The hydroelectricity plant of Kastraki is located 35 km at the downriver of the dam of Kremasta and north of Agrinio town. Its purpose is energy production, water supply and irrigation of the Agrinio area. The drainage basin of the reservoir is 4,118 km2.





General information


Location: Aitoloakarnania prefecture

Dam type: earthfill (TE)

Dam Height: 96 m

Crest Length: 547 m

Dam Volume: 5.2 x106 m3

Reservoir capacity: 785 x106 m3

Reservoir surface: 24 x106 m2

Use: HSI (Hydropower, Water Supply, Irrigation)

Power: 320 MW

Energy: 598 GWh/yr

Owner: Public Power Corporation (PPC)

Year of operation: 1969



§         BROCHURE

§         VIDEO

The Stratos Hydroelectric Dam (Greek: Υδροηλεκτρικό φράγμα του Στράτου Ydroilektriko fragma tou Stratou) is a dam that dams up the Acheloos River just east of Stratos and north of the GR-5/E55 (Antirrio - Amfilochia - Ioannina). The dam was first constructed in 1989 and created the Stratos artificial lake, the fourth of the lakes in the Acheloos projects after the Kastraki and Kremasta lakes. The dam is used for hydroelectricity production and irrigation as well.  In the dam contains two units of electrical production which powers up to 150 MW of electricity (STRATOS I and STRATOS II). The drainage basin of Stratos is 4,320 km2.


General information


Location: Aitoloakarnania prefecture

Dam type: earthfill (TE)

Dam Height: 26 m

Crest Length: 1900 m

Dam Volume: 2.8 x106 m3

Reservoir capacity: 11 x106 m3

Reservoir surface: 8.4 x106 m2

Use: HI (Hydropower, Irrigation)

Irrigated area: 400,000

Power: 150 MW

Energy: 237 GWh/yr

Owner: Public Power Corporation (PPC)

Year of operation: 1989






Acheloos River Diversion Scheme

(short review)


The partial Achelous river diversion is a complex a technical work that has its origin 30 years ago. The initial design of the work included the following part works:


·         Two dams with the commensurate reservoirs and hydroelectricity stations in Mesochora and Sykia locations

·         Diversion tunnel of Achelous dam towards Thessaly valley, 17.5 klm long. The total amount of water was estimated to 1,100 million cubic meters annually.

·         Open air hydroelectricity station in Pefkofyto region, located at the tunnel’s outlet

·         Two dams with the commensurate reservoirs, connection tunnel at Pyli location in Trikala prefecture and in Mouzaki location in Karditsa prefecture and hydroelectricity station at Mouzaki

·         Regulation tank at Mavromati region and hydroelectricity station at the same region


For these works have been contacted three environmental impact assessment studies, have been given two approval decisions for environmental terms. The Supreme Administrative Court has cancelled these two approval decisions. After that the Ministry of Environment has contacted new integrated environmental impact assessment in 1995. By this study the initial design was altered. More specific: 1.  The total amount of water to be diverted was minimized to 600 million cubic meters annually 2. The diversion scheme altered. Thus the party works are:


·       The Sykia dam and the homonymous hydroelectricity station

·       The diversion tunnel 17.5 klm long

·       The hydroelectricity station Pefkofyto in diversion tunnel’s outlet.

·       A regulation work in Mavromati




Picture 1. Sykia Dam, major project element of Achelous River Diversion (source:  )




Achelous River Diversion Scheme, Greece


Key Data


Estimated water transfer

600 million m³

Project elements



Mega dam (150m) and reservoir


MesochoraGlystra tunnel (7.5km)


Mega dam (150m) and reservoir


Sykia diversion channel to Thessaly (17.4km)


Major dam (135m) and reservoir


Dam (90m) and reservoir

Original funding estimate


National budget contribution


Estimated construction costs


Estimated total project cost

€3–4.5bn (1996)

Area to be irrigated

240,000ha to 380,000ha

Project Timeline


First suggested




Cost benefit study commissioned


EU funding applications


Opposition campaign launched


EU rejects funding application


First restraining order issued


Bern Committee formal complaint


Greek ministerial approval of EIA


Tunnel contract awarded


Second restraining order issued


Ministerial approval ruled illegal


National budget allocation announced


Resumption of construction


Construction suspended


Parliament pass legal amendments to allow work to proceed

19 July 2006

The Supreme Administrative Court poses 14 questions to The Court of Justice of European Union regarding the legality of diversion scheme

9 October 2009

Achelous Diversion works are temporarily suspended until The Court of Justice of European Union answer the questions

10 February 2010

Key Players


Client / sponsor

Ministry of Environment, Regional Planning and Public Works, Greece

HEP operator

DEH - Greek Public Power Corporation

Main contractor (diversion tunnel)

Impregilo-Gnomon-Tegk consortium

Financial consultants to Greek Government (cost benefit analysis)

Morgan Grenfell

Financial consultants to European Union (funding application)

Coopers & Lybrand

Engineering, installation and commissioning (Sykia and Pefkofyto HEP plants)

Prometheus Gas SA (in consortium with German and Russian supplier companies)

Other contractors

Itia, Kalaouzis, Electrowatt, Marinos, Koutsoyiannis

Environmental NGOs

WWF Greece, Hellenic Ornithological Society, Elliniki Etairia , Hellenic Society for the Protection of Nature WWF Germany, WWF UK, Greenpeace, Birdlife International, RSPB, European Environmental Bureau, Ornitologisk Forening (Denmark)


Sources & related websites:







6. (9/10/2009 – “The Supreme Administrative Court has posed 14 questions to The Court of Justice of European Union”, from skai tv)

7. (10/2/2010 – “Achelous Diversion works are temporarily suspended”, from skai tv)

8.     Koutsoyiannis, D., Study of the operation of reservoirs , General outline of the Acheloos River diversion project, Contractor: Directorate for Acheloos Diversion Works – General Secretariat of Public Works – Ministry of Environment, Planning and Public Works, Collaborators: G. Kalaouzis, ELECTROWATT, P. Marinos, D. Koutsoyiannis, 420 pages, 1996 ( )

9.     THE RIVER ACHELOOS DIVERSION SCHEME, Kimon Hadjibiros, Assistant Professor, National Technical University of Athens ( )