Woodbridge Town Council

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Operation of the floodgate at Whisstocks Place

16 August 2018

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We have had several queries regarding the operation of the floodgate at Whisstocks Place during its recent closure. This notice will attempt to answer questions that have been raised about its operation.

Woodbridge Town Council was not involved in the specifications for the gate nor in its design, construction or installation. It is not automated, not electrified and has to be closed and opened manually. This operation is carried out by a team of qualified engineers from Suffolk Coastal Norse on our behalf using a battery operated hydraulic winch, cables and other equipment they have to transport to Whisstocks Place each time the gate has to be closed or opened.

Closure and then opening of the floodgate is undertaken on the instruction of the Environment Agency as the statutory body who issues severe weather, high tide and flood warnings. It is not a decision made by Woodbridge Town Council but a decision with which we are legally bound to comply.

Every floodgate individually has a ‘trigger level’ at which it must be closed depending on its level above the ‘local high water mark’. The Whisstocks floodgate is the lowest floodgate in Woodbridge so is the first to be ordered to be closed. The floodgate next to it on Tide Mill Way is approximately 4 feet higher than the Whisstocks floodgate so will frequently be open when our floodgate has been ordered to be closed.

The floodgate itself is 11 metres long and weighs 3.5 metric tons. To close the gate and ensure its integrity against flooding takes a minimum of 45 minutes after all the winches, cables etc have been connected and secured in position. This process involves securing a battery operated hydraulic winch to the ground, attaching a high tension cable to the floodgate and dragging it closed. It then needs a pneumatic seal around the sides and bottom of the floodgate to be inflated under pressure to ensure the floodgate is watertight.

For health and safety reasons, members of the public need to be kept well clear of the area when the floodgate is being opened or closed.

Working with the Environment Agency, Woodbridge Town Council has in place contingency emergency plans to deal with a partial or complete failure in the operation of the floodgate. This includes having arrangements with a local company to hold on our behalf and to deliver and install in an emergency such as an exceptional tide or tidal surge 135 x 1 ton bags of sand to block the 11 metre opening.

Please note that Woodbridge Town Council is under a ‘pre-warning’ from the Environment Agency that the Whisstocks Floodgate will probably be instructed to be closed from 21 to 26 August and 8 and 9 September. Such notices are confirmed or ‘stood down’ closer to the specified dates. ***UPDATE*** It is now highly unlikely the floodgate will be closed from 21 to 26 August. Pre-warning remains in place for 8 and 9 September. 

We will do our utmost to keep local residents informed of expected closures.

To watch a time lapse video of the floodgate being closed please click here.

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