The initial contact included distinct sub-projects that were necessary to attain the initial project of supplying water to the capital. The conservation of the existing water supply network, the reconstitution of the Aqueduct of Hadrian, the transfer of seawater from Faliron were some of the sub-projects. Among the major construction works constituted the Marathon Lake and dam project, the construction of the Boyati Tunnel, the water treatment plant "above Patission" and the water distribution network to consumers. In order to better organize the project, EYDAP undertook the construction of a small electric power plant, the improvement of the infrastructure of the port of Chalcis, and the building of a settlement destined to house up to 1,000 employees. This number corresponds approximately to one-third of the work population, as the rest of the employees came from the neighboring villages.