In 1978 King’s Lynn suffered extensive flooding caused by a North Sea storm surge which also caused considerable damage on the entire east coast of England. King's Lynn suffered worse flooding in 1978 than in the storm of 1953. The River Ouse overflowed onto the Quays, King Street and the town’s medieval quarter and the town centre was left underwater causing damage totalling millions of pounds. At St Margaret's church in the town the flood depth was measured at 1190mm.
In response to that flood event, sixty flood gates and flood barriers were installed to protect the town against future flooding.
Some thirty years later on 5 December 2013 the defences were tested to their limit in that year’s storm surge event and held back the floodwater with great success. However, a refurbishment programme was deemed necessary for any future flood events.
Flood Control International was selected to replace a number of the worn out gates and flood barriers and refurbish the remainder as part of the Environment Agency scheme following this event.
Over sixty gates were involved: those that could be refurbished were removed, refitted with seals and hinge mechanisms where required, and then rehung and tested. Every existing gate had its own unique set of issues, from sticking hinges to insecure locking devices, or from corrosion to worn seals.
As well as refurbishing thirty of the gates, 15 new vehicle flood gates and 15 new demountable flood barriers were installed as part of the project. The new flood gates were selected due to their ease of use, as well as their effectiveness. The flood gates and flood barriers are operated by the local Environment Agency teams on high tides a number of times every year, and with so many gates, operation had to be quick, easy and reliable.
Flood Control International had a number of challenges to overcome. Bespoke gate designs were utilised to protect some areas where access was severely limited such as at the ferry landing stage - where work had to be undertaken safely in between ferry landings.
One element of the work also included a number of flood barrier ‘seats’ that pivoted upwards to form a flood barrier with the adjacent wall when required. Gas struts were utilised to reduce the effective weight of these barriers to make operation by one operative possible.
For the installation of so many flood barriers around the town in short timescales, bespoke storage trailers were designed for the beams and posts required.
The works were completed within the main contractor’s programme, and the gates handed over for another thirty years of service.