Annual Report for 2010/11 and Forward Programme - Sellafield Ltd

Figure 1 - Swath bathymetry of Scroby Sands windfarm, off the east coast of England, shows mobilebedforms (mega-ripples, scour pits, sand wave). The vertical red bars indicate the position ofmonopiles, and the purple line the line of the connecting cable. Red-orange areas indicate shallowerwater.The swath or multibeam survey data held by SL were analysed within the IVS3DFledermaus suite of visualisation and analysis software. This allows analysis of thebathymetry data to be undertaken at horizontal and vertical resolutions appropriate to thescale of the field of vision using a high speed “data mining engine”.3. Results3.1 Analysis of existing swath bathymetryThe “XYZ” data file held by SL was uploaded into the Fledermaus Package using a 1m by1m resolution in order to observe, characterise and map bedforms within the survey area.Figure 2 shows the coverage of the survey along the Cumbrian coastline, and reveals largescalebathymetric features.The swath bathymetry has been used by Halcrow to produce maps of the bathymetry alongthe Sellafield coastline (Figure 3). The data quality is sufficient to delineate large scaleseabed features, e.g. sand banks at a typical horizontal scale of ~100m, or for numericalmodelling purposes which uses a coarse resolution grid (~ 1km). The Halcrow report makesno attempt to go beyond this high-level interpretation.