This Natural Monument is located in a section of Âncora river. Its source is 805 m high, in Arga Mountain, and it flows into the ocean near Vila Praia de Âncora after a 21 km journey. The Âncora hydrographic basin, with an area of 77 km², lies between the Minho basin to the north and the Lima basin to the south (esq. A).

Cascades and other types of waterfalls

A waterfall is a sudden break in the slope of a riverbed. In what concerns the shape, there are various types of waterfalls: cascades, cataracts, plunge, block, punchbowl, among others.

A cascade is a particular type of waterfall presenting several steps naturally excavated in the rock which are originated by water erosion.

Cataracts are typically wider than tall and discharge a large volume of water. In plunge waterfalls, water falls without contacting the rock. In block waterfalls, the rock surface from which the water falls is wide. In a punchbowl, the water goes down along a narrow channel and is collected in a basin.

How waterfalls form?

The sudden break in the slope of a riverbed waterfall is associated with erosion which is related with certain characteristics such as (esq. B):

- the different strength of the rocks;

- the occurrence of faults and other tectonic movements; - sea level changes;

- the melting of glacier ice.

Ferida Má Cascades is 2.25 km long, between Montaria and Amonde, presents a high slope (7,6%), between 260 and 90 m of high, and is 15 m far from the coastline. Upstream, on the granite western flank of Arga Mountain, the slope is even more pronounced but downstream it becomes quite gentle (esq. C).

References:

Pereira, P; Henriques, R.; Brilha, J. & Pereira, D.I. (2019). Conteúdos científicos para a caracterização dos 8 monumentos naturais locais” enquadrado no projeto Geoparque Litoral de Viana do Castelo – 2ª fase. Município de Viana do Castelo, Relatório Final GEOSITE, 273 p.