Borda de Juanene, 31879, Navarra.
|self guided, L=5 km. D=2 h.
|Nacedero del Larráun.
|As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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The Nacedero del Larráun is, as the name says, the source of the Larráun River. The Basque name is Aitzarratetako iturburua or Larraun ibaiaren iturburua. It is also known as Nacedero de Aitzarrateta (Source of Aitzarrateta).
This is a rather small spring, but it is a karst spring, located at the foot of a high limestone cliff, and it forms some rapids. The elevation of those rapids was used by a watermill, but only some ruins of the building remain. This cliff was created by the retrograde erosion by the spring itself. The river has cut a valley and flows northeast to the small village Iribas. The water of the spring is used as drinking water and to produce electricity. For this purpose a canal brings a part of the water to Iribas, where about 500 m south of the village, a estación depuradora de agua potable (drinking water treatment plant) is located. But only a part of the water is used as drinking water. The rest flows in the canal to Iribas, where in the valley below the village, east of the church, a small hydroelectric power plant named Central de Iribas generates electricity. These are not the only sights along the way, there are numerous small caves along the valley. Right below the water treatment plant is the Lezegalde leizea or Lezegaldeko leize-zuloa.
The spring is only 250 m from the road NA-7510, although it is much lower and there are several serpentines in the way down. This is the obvious access to the spring, the trail starts at km 5 of the road. Main drawback is the lack of parking space, and it's forbidden to park along the narrow road.
There are numerous walking trails published on the web, which start at Iribas and follow the valley to the spring, They are, depending on the actual route between 4.5 and 5 km long and typically include all above-mentioned sites. There are several educational signs along the trail, and the route is very well signposted. We strongly recommend this route. With enough time for the ascending and some sightseeing it may take 1.5 to 2 hours.