financial backing to complete the average-sized project. Under EEY, a Ulen-controlled consortium with the Bank of Athens and the Greek Government was formed. Construction The foundation stone for the dam was laid in October 1926 by Prime Minister Alexandros Zaimis; Venizelos was also present at the ceremony. With 450 workers, construction continued on the dam and water network for three years and in 1929, the reservoir began to fill. Work on the dam and water network was complete in May 1931. A year after inauguration, the Boyati Tunnel was transferring per second of water treated at the Galatsi Water Treatment Plant to Athens. The dam would serve as the primary water supply for Athens until 1959, when water was pumped from Yliki lake. Seismicity During and after the filling of the Marathon Dam's reservoir, there was seismic activity, with all the epicenters being within of the reservoir. The first earthquakes were felt in 1931, with two 5MW+ earthquakes occurring in 1938. All but two of the earthquakes were believed to have occurred during rapid rises in the reservoir level. This seismic activity is the earliest known example of earthquakes being caused by reservoir filling. Design The dam is a tall, long gravity dam with a crest width of and base width of . The dam's spillway is located near its southern abutment and is an uncontrolled chute-type with a discharge capacity. It is at an elevation of above sea level while the dam crest is at . The dam creates a reservoir with a maximum capacity of of which is usable. The reservoir has a maximum depth of and surface area of The dam is located at the head of a drainage area with an average annual run-off of , of which is captured. Average rainfall in the basin is . Symbolism The Marathon Dam was seen as a major symbol of modernization in Greece. The dam's location near Marathon signified a connection to Greece's past with the Athenians' victory at the Battle of Marathon, while its modern structure, the largest project in the Balkans at the time, signified a connection to the future and victory over nature. A replica of the Athenian Treasury temple at Delphi constructed at the base of the dam further illustrates the connection. A plaque on the temple reads: "To commemorate their victory at the battle of Marathon, the Athenians erected a treasury at Delphi.