Herodotus, taking notice of the shoreline-transforming power of the Acheloos River, even compared it to the Nile in this respect: It is said to have been called more anciently Thoas, Axenus and Thestius.

[3] The river Achelous begins at about 2,000 metres (6,600 ft) elevation on the eastern slope of Lakmos mountain in the Pindus range, near the village Anthousa in the westernmost part of the Trikala regional unit.

In antiquity, the Achelous was the largest and most celebrated river in Greece, rising in Mount Pindus, and after flowing through the mountainous country of the Dolopians and Agraeans, entered the plain of Acarnania and Aetolia near Stratus, and discharged itself into the Ionian Sea, near the Acarnanian town of Oeniadae.

It subsequently formed the boundary between Acarnania and Aetolia, but in the time of Thucydides the territory of Oeniadae extended east of the river.

Its waters are of a whitish yellow or cream colour, whence it derives a later name of Aspropotamo or the White river, and to which Dionysius Periegetes probably alludes in the epithet ἀργυροδίνης.

This plain was celebrated for its fertility, though covered in great part with marshes, several of which were formed by the overflowings of the Achelous.

The dam, made of concrete, took years to complete, eventually flooding a portion of the western part of the prefecture of Eurytania.

The goal of the project is to divert 600,000,000 m3 (490,000 acre⋅ft) annually from the river west towards the Thessaly plains in order to help irrigate 240,000–380,000 ha (590,000–940,000 acres) of mostly cotton crops.