First.
Travelling along the Canal del Freser aqueduct is currently prohibited (2026). This is stated on signs at the entrances to the aqueduct and in an official announcement. The reasons for this are the danger of rockfalls and the poor condition of the wooden deck and rock bridges.
See the official announcement here
Second.
The route itself is not difficult. However, it does require a certain amount of caution and attention. It is important to maintain the correct path when detouring around the siphon sections of the aqueduct, where the trail sometimes climbs up the slope among rocks and overgrown bushes. At the aqueduct itself, overgrown bushes in some places require careful walking along the edge of the cliff. The rotten boards of the wooden deck that cover the aqueduct also pose a risk. It is important to understand that falling into a watercourse can lead to tragic consequences due to the high speed and significant depth of the flow.
The real situation.
There is visible traffic along the canal, although not very intense. The Strava heatmap and the condition of the trail in the bypass sections show this clearly. But it is a little chance to meet anybody during the walk, even during the weekend.