In an area where the London Array Offshore Wind Farm export cables and the Kentish Flats Offshore Wind Farm cables cross each other, these high voltage cables are being protected by rock placements.
In total, four rock berms will be created, each approximately 150 metres long, 15 metres wide. Due to the height of the rock berms, the charted depth above these rock berms will be reduced to approximately 1 metre. The first rock berm has already been installed, and all the LAL export cables and rock protection is expected to be complete by the end of 2012.
In light of this change in charted depth, the UKHO has issued a Notice to Mariners/chart correction (622/2012 and 930/2012) giving the new charted depth in the area.
London Array Limited has consulted Trinity House Navigational Department. Trinity House has suggested that four special marks should be installed to square off the area of all four rock berms.
These buoys will be installed in the near future. Once installed, a relevant chart correction/Notice to Mariners will be issued via UKHO and Trinity House. At the moment, a guard vessel is in position in the Southern Estuary. The guard vessel will at regular intervals broadcast navigational warnings on VHF Ch. 16.
Over the next few years, there will be a number of different offshore construction activities ongoing in the Thames Estuary. Some of these are in relation to the construction of the London Array Offshore Wind Farm. All relevant Notice to Mariners/chart corrections will be issued via Admiralty Notice to Mariners/UKHO. For safety reasons, we encourage all sea users to update their navigational information on a regular basis. As well as using these formal channels, London Array is trying to reach stakeholders via a number of informal channels.
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Offshore WIND staff, April 26, 2012; Image: londonarray