The Libardón descends from limestone-slate mixed Picos country, a spate-responsive river arriving into the eastern network. The upper reaches show step-pool through mixed lithology; the descent is steep. The water carries the blended character of limestone and slate. The middle Libardón opens into partly-confined pool-riffle on mixed cobble. The pools are productive and hold traditional respect. The river's character is of responsive descent from high country. The wading demands attention throughout the upper sections.

Wading: Wet mudstone slabs in headwater gorge

In the mountain-to-sea trout rivers of Asturias, olives and other mayflies do much of the work in spring whenever levels and colour allow, followed by strong evening caddis and steady buzzer life through early and mid-summer, with terrestrials and mixed surface food from wooded, pastoral banks rounding out the diet whenever flows drop back into safe wading range.