Biodiversity assessment, habitat mapping, and environmental impact assessment from the decomissioning of a submarine pipeline near the port of Archirodon

4 months (February 2020 – May 2020)

Funded by:
Vassiliko Cement Works Public Company Ltd.

Project Description:
Vasiliko Bay is a heavily industrialized semi-enclosed bay which faces an increasing number of human pressures including aquaculture, tourism, naval base, ports, cement station,  power plant, energy infrastructure including VTTV jetty. Government plans are already underway for the expansion of hydrocarbon-related industries in the area and the establishment of anchorage areas, construction of storage facilities, deployment of submarine pipelines, and dredging for the facilities establishment.

In the present study, Vassiliko Cement Works Public Company Ltd. hired MER to conduct an environmental baseline survey and impact assessment from the decommissioning of an inactive undersea pipeline laying on the seafloor. The pipeline was installed in the 1970s and used for unloading petroleum (fuel oil) but was locked since it became inactivated for at least two decades. The exact route of the pipeline was unknown and toxic pollutants remained in the locked pipeline which imposed risks to the marine environment; especially in case of dredging and excavation activities.

The aim of this study was to map the pipeline and the priority habitats of the area using field visits, aerial and acoustic tools. The entire pipeline underwater route was video recorded divers, the seagrass Posidonia oceanica was mapped using GIS and the condition of the protected meadows was assessed using multiple shoot density measurements, biodiversity was recorded using underwater visual census carried out by scientific divers, sediment was collected with a Van Veen grab from several sites for physicochemical analysis, bibliographic secondary data were collated.

Possible impacts to the marine environment from the decomissioning works were assessed and mitigation measures were proposed.