Iijoki

Iijoki is a river of Finland in the region of Northern Ostrobothnia. The river has many tributaries. It flows for into the Gulf of Bothnia. Some of its main tributaries are Siuruanjoki and Livojoki. It has about 150 rapids.
Further reading.
Kalle Päätalo has written a 26 part novel; "Juuret Iijoen törmässä".