The Soča valley, and the river that is the wrong colour

Most rivers are some shade of brown, green or grey. The Soča is something else. It rises in the Julian Alps of north-western Slovenia and runs south towards Italy and the Adriatic, and for much of its length it is an extraordinary colour, a vivid turquoise-emerald that looks unreal even in photographs. The colour comes from the limestone it flows over. The water carries very fine particles of rock, and together with its clarity, the light it reflects and the white stones of its bed, they give it that milky, luminous green. It is at its most intense on a bright day, when the sun is high.

The river is clean and very cold, fed by snowmelt and springs, and in summer its rapids are full of kayaks and rafts. Its source, a spring in a cave in the Trenta valley, can be reached by a short, steep path with fixed cables. It is also famous for its trout, the marble trout, a species found only in the rivers of this part of the Adriatic basin.

Over the Vršič Pass

The most dramatic way into the valley is from the north, over the Vršič Pass, the highest road pass in Slovenia. The road climbs from Kranjska Gora in fifty hairpin bends, each one numbered, through forest and bare rock, past a small wooden Russian chapel built by Russian prisoners of war who worked on the road in the First World War, in memory of their comrades killed by an avalanche. At the top, at a little over 1,600 metres, there are views across the peaks of the Julian Alps.

The road then drops into the Trenta valley, where the Soča begins, and follows the river down to Bovec, a small town in a wide basin ringed by mountains, the centre for rafting and walking in the valley.

The Isonzo front

The Soča was not always peaceful. In the First World War, after Italy joined the Allies in 1915, the valley became the front line between Italy and Austria-Hungary. The Italians called the river the Isonzo, and for over two years they launched attack after attack across it in an attempt to break through to the east. There were twelve battles of the Isonzo, fought in terrible conditions in the mountains, and hundreds of thousands of men were killed or wounded on both sides.

The last of them, in October 1917, was a sudden breakthrough by Austro-Hungarian and German forces near the town of Kobarid, then known as Caporetto, which drove the Italian army back many miles. Ernest Hemingway, who served as an ambulance driver on the Italian front, described the retreat in A Farewell to Arms. Kobarid now has a museum of the front, and the trenches, tunnels and military cemeteries are still visible in the hills, linked by a walking route.

Kobarid is also a good base for the valley's walks. A short path leads from the town to the Kozjak waterfall, which falls into a green pool inside a narrow rock chamber, past Napoleon's Bridge, a stone arch over the Soča whose name recalls the French army that passed this way. The Soča Trail, a waymarked path of about twenty-five kilometres, follows the river from its source in the Trenta valley down towards Bovec, crossing it on suspension bridges above the green water.

The tours

Just You's Secret Slovenia, seven nights for solo travellers, starts in Ljubljana and travels to Kranjska Gora, over the Julian Alps to Bovec and Triglav National Park, with time at Lake Bled, Lake Bohinj, the Bohinj valley and Mount Vogel.

Travelsphere's Scenic Slovenia & Lake Bled, seven nights, follows the high road through Kranjska Gora and the Trenta valley to the Soča river, Bovec and the Predil Pass, as well as visiting Ljubljana, Bled and the Vintgar Gorge.

The Vršič Pass is usually open from late spring to autumn, depending on the snow. Summer is the season for swimming in the Soča's pools, if you can bear the cold. Late September and October bring autumn colour to the beech forests and empty roads, and the river is as green as ever.