Aposelemis Dam, Water Treatment and Water Supply Projects in Northern Crete


Project description


The project concerns the greater Heraklion and Ag Nikolaos towns water supply and includes the dam, the reservoir, Aposelemis reservoir water mains, TBM tunnel for diversion from the Lasithi plateau, water mains to the treatment plants, water treatment plants, water mains to Heraklion and Ag. Nikolaos, other access works and road construction.


The dam is 56 m height. It is of rockfill type with an impervious clay core, upstream and downstream rock cells, spillway, spillway delivery canal and flip bucket

  • The Lasithi plateau diversion to the Aposeslemis reservoir includes a TBM excavated 3,5km long and 14% steep tunnel
  • The water treatment plants include pre-ozonation, coagulation, sedimentation, filtering, post-chlorination and sludge treatment
  • The main pipelines from the dam to the water treatment plant, ~ 8 km long, consist of D1200 and D1100 steelpipes and 2 tunnels (1590, 2050m long).
  • The water main to Heraklion is a D1100 to D500 steelpipe, ~30 km long.
  • The water mains to Ag Nikolaos (~ 32.5 km long) are a D500 to D600 steelpipe and a 670 long, 3m diameter tunnel.

Services: Consulting, Design
Consulting Services: Technical, Management
Expertise: Dams and Reservoirs, Hydrology, Procurement, Project finance, Project Management, Tender Documents, Water, Water Resources Management
Country: Greece
Region: Crete Prefecture, Crete island
Client: Hellenic Ministry of Development, Competitiveness, Infrastructure, Transport and Networks
Services provided

Co-ordination and representation of professional individuals and companies forming the Joint Venture for the technical and managerial provision services.
Multiple contracts required design, tecnical and management consultant services for construction.

  • Dam and related works study revision
  • Pipeline to Heraklion and Ag Nikolaos.
  • Water treatment plant
  • Additional Environmental Impact Assessment of the Lasithi plateau
  • Impact assessment and remedial measures for St Konstantinos church
  • Hydrologic studies and modeling. Flood design study
  • Water resources management
  • Water saving measures definition study for the city of Heraklion
  • Study for the issuing of a Water Regulating authority– Phase A and specifications for phase B
  • Specifications and tender documents for the Leakage determination and control, Water Resourses and Works (Phase B) Regulating authority creation studies
  • Tender Documents review and update.
  • Construction Supervision Support on site and in Ministry headquarters.
  • Validation of submitted bills of quantities and contractor payments.
  • Quality control.
  • EU funding assistance
  • Dam break analysis
  • Emergency Action Plan


The technical and management consultant provision of services included:

  • Resident engineers. Specialised staff was assigned on site
  • Existing data were reviewed (studies, investigations etc)
  • Regular onsite visits and meetings with the client and experts were made
  • Experienced scientific staff

Services current status: Completed
Construction progress: Under construction

35.3121, 25.091

35.2498, 25.4005

35.3022, 25.3564