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Stwlan Dam sits high above Tanygrisiau in Eryri (Snowdonia) National Park, surrounded by the rugged Moelwyn mountains and the remains of the region’s slate-quarrying past. This 35-minute walking video follows mountain tracks and the access road toward Llyn Stwlan, with compact gravel, rough stone, grassy sections and occasional uneven ground.

The landscape changes between open mountain slopes and old industrial workings, with slate remains scattered across the hillsides. As the route approaches the reservoir, the massive Stwlan Dam becomes a prominent feature against the surrounding mountains. Beyond it, the rugged slopes and valleys of the Ffestiniog area open out across the landscape.

The actual approach to the dam has a noticeable uphill character, although the video uses around 5 km/h at 0% treadmill incline, keeping the walking effort relatively easy. A 2–4% incline would give an indoor walking workout more of the steady climbing feel found on the mountain road.

Llyn Stwlan is the upper reservoir of the Ffestiniog pumped-storage hydroelectric scheme, with the dam positioned high above Tanygrisiau. The reservoir sits within a landscape already heavily shaped by industry, where old quarry tracks, inclines and abandoned workings remain visible among the natural mountain terrain.

The Moelwyn mountains were extensively quarried for slate, and historic transport routes once carried slate down toward the Ffestiniog Railway. Today, the old quarry landscape and modern hydroelectric infrastructure sit alongside the open mountain scenery, creating an unusual mixture of industrial history and wilderness.

For a virtual walk or treadmill walking session, this is a distinctly rugged Eryri route. The scenery moves from mountain tracks and quarry remains toward the reservoir and enormous dam, with the surrounding Moelwyn landscape providing a constant backdrop.