The Power of Water in the Cogne Valley

12/04/25

We have visited the Aosta valley so many times, but there are still new things to do even if we stay in the same places. In this blog post we visit three park ups we’ve been to before but the visits all felt pretty different.

Aymavilles

Near the entrance to the Cogne valley, Aymavilles was a park up we’d used before but we had no memory of it until we checked our blog. This is one of the reasons we continue keeping a blog. It helps jog the memory. Although in this case we still didn’t have much of a memory of the park up or the town.

Last time we visited we noted that we didn’t make it to the castle. So our first mission was a walk from the sosta up through the town to the castle. We picked an odd route up some terracing that seemed to channel either a drain or an aqueduct. We were too late to see inside the castle, but it is open for guided tours now, all the renovations we saw happening last time are complete. Instead we walked around its perimeter taking in the 18th and 19th century modifications that have been made to the original medieval four-tower castle. It looks too symmetrical to be real, especially with the pristine restoration of the external decoration.

Pont d’Aël

The following morning we made our way to the modern road bridge over the Grand Eyvia (the river that runs down from the head of the Cogne valley). In its lower stretches the valley is steep sided and narrow which made it possible for the Romans to build the Pont d’Aël, the objective of today’s walk.

We started with a climb up up the side of the valley and then a traverse high above the river and road that we knew were below us but couldn’t see due to the steepness of the cliffs. The recent hot sunny weather meant that the path was dry and dusty. We were accompanied by the rustling of lizards in the grass as they darted away from our footsteps. Once the path would have taken us through woodland, but today we were walking through the blackened remains of trees that had been burned in a wildfire the previous summer.

As the surroundings became more rocky we could see a cascade of water dropping from a small hydro electric plant high above us  The path routed us through a tunnel behind this stream so that we didn’t get a clear view of the waterfall until we were on the way home. The cool tunnel was a welcome relief from the heat, even more so when we found the window carved into the rock allowing us to feel the water’s spray. We tried to find out what this tunnel had been built for, but couldn’t find any information, we can only surmise that it was part of the hydro scheme which had possibly diverted or changed the nature of the water falling from above.

The Pont d’Aël spans a 12m wide gorge at the village of the same name part way up the Cogne valley. After we’d exited the tunnel the path started to drop and the river steadily rose to meet us. We started to get glimpses of the bridge in the narrow cleft of the valley.

Distant view of the Pont d’Ael

The Pont d’Ael was probably more important to the Romans as an aqueduct than as a bridge. Water was channelled from higher up the Grand Eyvia and routed down, across the river here at the Pont d’Aël and along the valley, providing water to a quarry situated somewhere between Aymavilles and Aosta. On the side of the aqueduct is the original inscription telling us that it was built by Caius Avillius Caimus during Emperor Augustus’ thirteenth consulship – in the year 3 BCE.

Anyone can walk across the top using the original water channel. The original pedestrian thoroughfare is below the aqueduct, inside the bridge. We paid €5 each to walk through this internal corridor. Glass floors gave us views into the internal structure of the bridge, the empty spaces beneath us designed to make the whole structure lighter.

To walk back we climbed out of the other side of the village and up to the valley road which we crossed to pick up a track which followed another, modern, aqueduct. It seemed to be a maintenance track rather than an official footpath but it was an easy way to get back to Aymavilles with just a final steep downhill bringing us out at the church of St Léger.

Returning to Aymavilles

Overnight in Cogne

After our walk we drove up to Cogne. Last spring there was significant flooding in a lot of locations in the Aosta valley. Cogne was one of the areas most significantly impacted, the road had been washed away leaving the villages higher up the valley cut off. These valleys are used to avalanches, rockslides and floods but this was something else. The pictures at the time were dramatic and we were interested to see how much progress had been made with repairs. We passed huge boulders in the river bed and could see where the river had scoured out rock and earth from the river banks. Where the road gets close to the river there was work going on building a new bridge and reinforcing the road. Smaller vehicles were directed on an alternative route up the valley. Now we’re in our new nippy van we were able to take this route rather than blocking the traffic on the original road.

When we got to Cogne we drove into the sosta which has been updated since we were last there. I hesitate to say improved. New electricity bollards have been introduced but were not working. The cost of the sosta has increased (electricity will be an additional cost too), and the friendly woman who manned the office before has been replaced with a machine. We toyed with driving up to Lillaz but decided to stop for the night and suck up the cost. Mainly to allow us to go into town and visit the lovely bakery. Despite it being a weekend the huge sosta had only one other van chose to stay. I don’t know if it is in response to the price of the sosta or because people were saving themselves for the impending Easter weekend.

Lillaz

After picking up some goodies at the bakery we decided to move onto Lillaz. The sosta in Lillaz is now using the same entry system as Cogne but the electricity bollards have not yet been replaced, meaning they were working and there was no additional cost for hooking up.

Looking at the sosta in Lillaz from across the river

The snowy mountains around us were beckoning so we picked up our snowshoes and microspikes and embarked on a walk up into the hills. Our first stop were the Lillaz waterfalls which are pretty but weren’t looking especially spectacular – probably meaning that not a lot of snow was melting further up stream.

Lillaz Waterfalls

The paths around the waterfalls were already icy and we had to don our microspikes to get higher up into the hills. As we ascended the snow got deeper and we switched to snowshoes. It was hard going and we decided to turn around at the Alpe di Loie, there was just so much snow and we could see clouds gathering in the valley, promising more.

On the way down we were surprised to see a pair of walkers in our footsteps, using branches as walking sticks and without any snow equipment. They asked us how the path was ahead and we explained we had just turned around because of the snow. It turned out they had followed us thinking that if we could do it so could they, I was impressed with the fact they had come so far but a little worried for them on the return, going down a steep slippery slope is a lot harder than going up. One of them wanted to continue but the other was clearly fed up and just wanted to turn around. She ended up winning their argument and they started back downhill while we swapped from snowshoes back to microspikes. We soon passed them again as they tentatively picked their way down the path. I could hear her muttering under her breath as we passed, obviously frustrated.

Leaving Italy

Overnight it snowed, none of it settled down in the village but we could see the new snow on the trees. The weather was breaking and more snow (a lot of snow) was forecast. Although it was very tempting to hang around for it, we had a ferry booking.

We made an early start down the valley and popped back to Aosta for some Italian themed shopping before driving back through the Mont Blanc tunnel.

Time to return to France.