The Oria river rises in several springs and their corresponding streams flowing down the dramatic slopes of the valley that merge in a main stream before the nucleus of the town .
The Oria river is the longest one in the province of Gipuzkoa .
The Oria river , the longest one in the province of Gipuzkoa , rises in several springs and their corresponding streams flowing down the dramatic slopes of the valley that merge in a main stream before the nucleus of the town .