Lake Copais, Kopais, or Kopaida (ancient Greek Κωπαΐς, modern Κωπαΐδα) used to be in the centre of Boeotia, Greece, west of Thebes until the late 19th century. The area where it was located, though now a plain, is still known as Kopaida.
While it still existed, the towns of Aliartos (ancient Haliartus), Orchomenus, and Chaeronea were on its shores. Rivers running into the lake included the Cephissus, the Termessus, and the Triton. The lake was (and is) surrounded by fertile land, but the lake increasingly encroached on the surrounding land because of inadequate drainage. In response to this, in 1867–1887 Scots and French engineers reclaimed the land for the British company Lake Copais Ltd., by building channels to drain water from the lake to the Cephissus and from there to Lake Yliki (Ylíki Limní, ancient Hylica). In total about 200 km² were reclaimed. This land was returned to the Greek government in 1952.
Kopais Lake Agency was created in 1957 to supervise the draining of the lake and construction of a new road. The task was completed during that same year, but the agency with full-time staff of 30 (including a driver for the president of the agency) still existed until 2010.
Before this the lake drained into the sea by numerous subterranean channels. Some of these channels were artificial, as the 1st century geographical writer Strabo records. Modern excavation has discovered enormous channels created in the 14th century BCE which drained water into the sea to the northeast; Strabo mentions work being done on these channels by an engineer named Crates of Chalcis at the time of Alexander the Great.
Lake Copais in ancient literature and mythology
Homer and other ancient authors refer to Copais as the "Cephisian lake", named for the river Cephissus. Strabo, however, argues that the poetic expression refers to the smaller Lake Hylice (the modern Lake Yliki), between Thebes and Anthedon.
There was a legend that the lake came into being when the hero Heracles flooded the area by digging out a river, the Cephissus, which poured into the basin. Polyaenus explains that he did this because he was fighting the Minyans of Orchomenus: they were dangerous horseback fighters, and Heracles dug the lake in order to unhorse them. Another story has the lake overflow in the mythical time of Ogyges, resulting in the Ogygian deluge.
- "Buildings of the Installations of Copais Company", Hellenic Ministry of Culture, accessed 12/2011; "Mycenaean Gla", accessed 12/2011.
- "The 'Atimorisia' Illness: Greece's Toothless Battle against Corruption - SPIEGEL ONLINE - News - International". Retrieved April 2012.
- Jason Manolopoulos (2011). Greece's 'Odious' Debt: The Looting of the Hellenic Republic by the Euro, the Political Elite and the Investment Community (Anthem Finance). Anthem Press. p. 288. ISBN 0-85728-771-0.
- Strabo 9.2.18.
- "Buildings of the Installations of Copais Company", Hellenic Ministry of Culture, accessed 12/2011; "Technology in Ancient Greece", accessed 12/2011.
- E.g. Iliad 5.708; Pausanias 9.24.1 makes the identification explicit.
- Strabo 9.2.20.
- Diodorus Siculus 4.18.7; Pausanias 9.38.7.
- Polyaenus Strategemata 1.3.5.
- Entry "Ogyges" in Oskar Seyffert, A Dictionary of Classical Antiquities, Revised and edited by Henry Nettleship and J.E. Sandys, New York: Meridian Books, 1956.
- Pausanias 9.24.2; Aristophanes Acharnians 880.
- Strabo on Lake Copais — see especially 9.2.16-27 (Perseus, tr. H.L. Jones, 1924)
- Pausanias on Lake Copais (Perseus, tr. W.H.S. Jones and H.A. Ormerod, 1918)