Recent evolution of the Messolongi Lagoon (Western Greece)

Abstract

The evolution of the Messolongi lagoon and the Acheloos river during the Holocene are controlled by the sea level fluctuations and the Quaternary tectonics of the area. The Acheloos river was not able to cross the gorge located to the north of the depression of Etolikon, very probably aggraded, and was forced to build a new channel flowing west of the gorge. Therefore the river moved the mouth in correspondence of Nisos Tholi, westward to the previous, flowing on the deltaic plain of Messolongi. The course of the Acheloos has moved more and more westward to the actual mouth with a strong progradation of the plain and of the mouth incorporating some of the Echinades Islands, as observed by Thucidide. At present all sandy barrier ridges of the lagoon of Messolongi have been eroded as the subsidence of the wider region was not compensated by the fluvial supply. The sandy bodies that encircle the Klisova Lagoon are still present because of the continuous supplying of the river Evinos.