The Passirio drops off the Timmelsjoch at nearly 3,500 metres, a very long way up, and spends its energy covering some forty kilometres down through the Passeier valley before it slides into the Adige at Merano, past the spa hotels and the palm trees that always look faintly confused to find themselves this far north. The water carries no such confusion — it runs off gneiss and mica schist, and it shows: clear, quick, faintly green in the deeper glides. Brown trout hold through the riffled upper valley; work down towards Merano and the pools deepen enough to hide marble trout, the fish South Tyrol quietly considers its own. Grayling turn up too, often enough that local guides talk about the Passirio's 'Grand Slam' — three species, one river, one reasonably ambitious day. None of it is secret water; it runs through a town. Fish it anyway. Town rivers with proper gradient and proper gravel don't come along often.

• Gneiss