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In the months of May and June 2023, LS Engenharia Geográfica carried out high-resolution hydrographic surveys in the maritime area of Armação de Pêra. The main objective was to obtain hydrographic data on what is the largest natural reef in Portugal, for a study promoted by the Centro de Ciências do Mar da Universidade do Algarve (CCMAR).
Hydrographic Survey Specifications
The specifications for this work provided for the acquisition of hydrographic data using multibeam systems, therefore, Exclusive Order hydrographic surveys, according to the specifications of the International Hydrographic Organization. The parameters to be observed in an area of approximately 200 km2 would be the bathymetry and the water column, but also the geological characterization of the bottom.
Challenges and Characteristics of the Region
Pedra do Valado – the popular name given to the reef – is located approximately 3 nautical miles from Armação de Pêra. Navigation in the area – with depths ranging between 10 and 30 meters – is not a demanding challenge, although there is always a lot of wind and swell, which sometimes makes it difficult to acquire data with the required quality. These operations involved the mobilization of a team that included 2 hydrographic surveyors and a sailor, and the appropriate logistics for this type of survey, which requires the use of sophisticated equipment and additional care to maintain the quality required to carry the job.
Hydrographic Coverage and Natural Beauty
The Hydrographic Survey of this area is carried out in “strips” with a side overlap of 20%, in order to guarantee total coverage of the bottom. In a total work distance of around 334 nautical miles (618 km), it was possible to confirm – through bathymetry – the theory that this was once an emerged coastal area. Today, the largest shallow coastal rocky reef in Portugal, it is one of the richest areas in biodiversity, with around 905 identified species, equivalent to 70% of the entire Algarve marine coastline, which is important to know, protect and value.
