Ölfusá river
Selfoss
Ölfusá river is the most voluminous in Iceland, with an average flow of 423 m³/sec.
Three large floods occurred in the 20th century, and beside the restaurant, Tryggvaskáli, are lines showing each flood's height. All the floods happened during the wintertime due to heavy rains and high temperatures, which caused the snow to melt unusually fast.
Ölfusá River is relatively short, about 25 km (14 miles) long. About 6 km (4 mi) north of Selfoss are two rivers, Sogið and Hvítá, and combined form Ölfusá.