CEFAS24-28 Contract for BEEMS Bathymetric and Bank Surveys, Sizewell, Suffolk

The BEEMS (British Energy Estuarine and Marine Studies) programme is funded by Sizewell C Limited. Through this programme, Cefas provide authoritative scientific information on the marine and transitional waters in the vicinity of potential new build nuclear power stations.

The purpose of this procurement is to provide bathymetric data for the Greater Sizewell Bay (GSB) to assess the geomorphological changes of the region, hence contributing to the ongoing monitoring of the Sizewell Coastline.

Two longshore bars (important geomorphological features) exist in shallow waters within the Area of Interest (AOI), with the inner bar being subaerial during some low tide periods. The results gained from the below specified surveys will support the calibration of Cefas instruments located on shore, as well as the ongoing monitoring of the Sizewell coastline. There is a high priority for the furthest landward coverage possible to be achieved by the survey, so that bathymetric data can be meshed to aerial topographic surveys of the beach, typically undertaken at low tide.

In addition to the above, the survey also seeks to obtain Side Scan Sonar (SSS), alongside multibeam data, to detect the presence of potential Sabellaria reef in the offshore infrastructure area. This area has previously been surveyed and shown to comprise outcropping Coralline Crag, which supports Sabellaria formations, and as such the data should be of high enough quality to determine and detect potential reef areas.

Cefas require two shallow water Multibeam Echosounder (MBES) bathymetric surveys to IHO Special Order (at a minimum) within the Greater Sizewell Bay (GSB) as below:

1. Spring Survey - Full extent (offshore) bank survey (MBES) undertaken in the Spring/Summer months; with data collection in nearshore AOI (MBES) and an offshore infrastructure area (MBES and SSS) to be prioritised first.

2. Nearshore Autumn survey (MBES only).