****Øyarvatnet or Øyarvatn is a lake in Agder county, Norway. It sits on the border between the municipalities of Valle and Sirdal, about 30 km northeast of the village of Lunde in Sirdal and about 32 km west of Austad in Bygland. The lake is part of the Kvina river system. It is located just to the south of the lake Rosskreppfjorden, which flows into it. The dam at the south end of the 8.05 km2 lake keeps it at an elevation of 837 m.