Located on the right bank of the estuary that forms the river Lima near its mouth, and in the heart of the city, the Parque Ecológico Urbano of Viana do Castelo, covering about 20 hectares, is located on the Lima floodplain, which results from the deposition of sediments such as gravel, sand and silt. This type of environment is crucial for the formation of certain types of habitats, allowing the colonization of different living beings.

The Park is fed daily by brackish water from the tide and also by fresh water from the S. Vicente stream (ribeira), forming transitional habitats, perfectly adapted to variations in salinity. Here plant species that tolerate the permanent presence of water in their roots (hydrophytic vegetation) and salinity (halophyte vegetation) predominate, and can be considered as the “First Halophyte Park in the Country”. This habitat is very important both for the sedentary birds that inhabit and nest here, as well as for the migratory birds that need it as a stopping, resting and feeding point.

The Urban Ecological Park is also known as “Caldeira de D. Prior” or “Caldeira de Maré”. It was in this area that the conditions were met to retain water during high tide that would put the Azenhas de D. Prior tide mill (built in the early 19th century) into operation.

It is a space prepared for recreation, leisure, environmental education and nature conservation activities, integrated in the Environmental Monitoring and Interpretation Center (CMIA), which includes temporary thematic exhibitions, awareness workshops, training activities, celebration of thematic days, etc.