This Natural Area is set around the mouth of the Piedras River, where fluvial sediments along with tidal influence have formed a unique landscape comprising a system of marshes and an unusual sandy formation reaching from some ten kilometres, parallel to the coast, known as a "flecha litoral" (bar).

Mainly comprising Marram grass, broom and stone pine.

Besides protecting the coast from the force of the Atlantic Ocean, the vegetation provides shelter to interesting species like the chameleon.

The waters of this marshland are very productive, rich in invertebrates, crustaceans, molluscs and fish, which in turn are a source of food for water and marine birdlife that come to this area on their migratory routes. You can see waders such as the unmistakable oystercatcher with its white and black plumage, contrasting with its pink feet, and the bright-coloured red-crested pochard, which spends the winter here. You can also see cormorants and various species of gulls in flight.

When you follow the Flecha del Rompido Trail you will see the vital importance of this belt of dunes, formed on top of coastal sediment. You will be struck not only by the flora and fauna, but also by the beauty of this place. Its low profile, along with gentle tones of colour, make this a place of unique beauty.