It is formed by the connection of the rivers Karpenisiotis and Krikelopotamos at the location called Dipotama Prousou just before the Monastery of Panagia Prousiotissa in the region of Evritania. It is one of the most important tributaries of the Acheloos river and important feeder of the artificial lake of Kremasta. Its most beautiful point is in the gorge with the steep cliffs, the islets and the shady places where the plane trees grow.
It is considered one of the most "technical" rivers for rafting as it moves meandering, with continuous sharp U-turns, in a narrow gorge with foamy waves. This makes the route exciting. The rafting route of the river is about 9 km and is considered to be of the 3rd difficulty level and is ideal for the experienced athletes.