Above them the Krimmler Ache is a different river altogether: around fifteen kilometres of natural water up the Achental, trading open meadow flats where you can count the stones for short, tumbling mountain stretches where you can't count much at all. It is fly only and catch-and-release throughout, with ten rods a day, so the brown trout, brook char and grayling have had rather more time to think than you'd like. The water is snowmelt- and glacier-cold, the season starts when the snow says it does, and a warm afternoon can put a little colour in it by teatime. Small nymphs for the pocket water, a dry fly for the flats, and no particular hurry — the valley road is closed to private cars, so you'll walk in or take the taxi.

• Gneiss

• Ecology: High
• Chemical: Failing to achieve good