The river has carried rock debris, soil and parts of trees and plants from the mountain range of Aroania (also known as Chelmos, Χελμός), to deposit it in the valley. This occurs mainly in the wet seasons of the Quaternary. In addition, the Scree (rock fragments) from the surrounding mountains formed further layers of sediment in the valley. The surface of the valley was gradually covered by layers of clayish, fertile soil. Valley and river achieved their modern form. People of the villages and small towns cultivated the ground. At the confluence of the small rivers Λαγκάδα, Ξηρόρεμα and Kleitoras, coming from the carbonate mountains in the west, their alluvial fan expanded the valley drastically. Here, on a hill in the widened valley, the largest town of the valley has developed: Kleitoria. The local residents turned the whole valley into a picturesque, beautiful Cultural landscape with fields, gardens and many trees. Its name is Katsana.