- Time2h 40'
- Vertical rise55 m
- Vertical descent745 m
- Horizontal distance8,0 Km
- Type of journeyMountain Crossing
- Severity of the natural environment2
- Difficulty in movement2
- Amount of effort required2
From Respomuso refuge (2200 m), an obvious path signposted GR 11 borders the reservoir in a westerly direction some height above it, on the right bank. In the area near the dam a clear zigzag leads down (crossing route 08) to take us to the ancient ruins of the Virgen de las Nieves hermitage. The path follows the Aguas Limpias river on the right bank throughout this stage. Heading west on the first part of the route the descent becomes gentler. The first signs of forest start to appear, and on the left the Salto Pipós waterfall can be seen. The slope steepens and the path passes beneath a rocky outcrop (Paso dero Pino). On this stretch there is a fork to the right leading to the Ibons d'Arriel on a less obvious footpath. Ignore this fork and follow the GR marks which bear south-east to the left. After crossing the ravine from Os Arriels we cross Plano Cheto, the entrance to the spectacular Paso l'Onso mountain pass, where it was necessary to break through the rock to get through the gorge. The river can be seen far below and the precipice is high up (caution). Once through the pass, there is a turning (crossing route 23) to the right, towards Cuello de Soba and the Arriel peaks. Continue down the valley on the left hand track, somewhat more obvious, in a definite southerly direction. The final stretch of this walk crosses a couple of ravines and takes us over meadows and through dense forests until we head gently downhill to the end of the Sarra reservoir again (1438 m). This is accessible by vehicle on the paved road from Sallent de Gállego, although we can also continue to the town following the GR 11 markings.