South coast and eastern English Channel synthesis – geophysical survey cruise report

The MALSF have funded two regional environmental characterisation (REC) studies in the English Channel: the South Coast REC (James et al, 2010) and the Eastern English Channel Marine Habitat Map (EECMHM) (James et al, 2007). In 2009 the MALSF awarded a contract to a consortium led by the British Geological Survey (BGS) to provide a synthesis of the results of these two REC studies and fill gaps in the geographical coverage by extending the synthesis area to include the coastal platform from Newhaven to the east past Beachy Head to Dungeness.
The survey described in this report was designed to extend the geophysical survey coverage of the EECMHM (Figure 1) to the coast to match the adjacent South Coast REC coverage and enable an integrated dataset to be produced for the whole of the Synthesis area.
For planning and operational purposes a survey plan grid of around 600 km was devised. This was an aspirational figure based on good weather throughout the survey period with no operational problems. The planning grid also included lines within the EECMHM area for inclusion if time was available. In total 353 kilometres of survey were completed and provided a coverage which enabled a practical interpretation of the geology between Beachy Head and Dungeness to be undertaken.
The survey was carried out using a BGS owned surface tow boomer (STB), simultaneously with a hired C-MAX CM2 sidescan sonar (SSS) system. During the planning stages for the survey the inclusion of a multibeam system was considered but the logistics of mounting a multibeam on the Watchful was deemed too complicated and prohibitive within the survey budget.
This report provides a review of the survey procedures and outcomes.