 Earlier, before dams pooled the river into reservoirs, the river flowed gradually in broad turns which could be navigated by small boats.From "Stemberdalen" the valley again narrows with the hillsides steepening and the river channel increasing in gradient.At "Østerbø" ("Øvstebø, Aurdal"), at about , for a limited stretch the timberline reaches up to the middle of the hillsides.