Engineers building a new barrier to protect thousands of homes and businesses from the risk of flooding have shown off the latest stage of the development.
The £58m project is being funded by the Environment Agency and should protect Ipswich from all but a once-in-300-year event.
The barrier will be placed in a cofferdam (watertight enclosure) that has been built into the New Cut stretch of the River Orwell beside the Island site. It provides a dry area 10 metres deep in what would normally be the river.
The barrier will be lowered into the frame, that is currently being built, later in the year. The cofferdam will then be flooded and the current diversionary route of the New Cut will be filled in.
The flood barrier should become fully operational at the end of 2017 or in early 2018.
It will operate like a mini-Thames barrier and should offer protection to 1,600 homes and more than 400 businesses.
Once fully operational it will be tested every month and is expected to be needed to give protection about once every 12 years – the same as expected use of the Thames Barrier before it was commissioned, although that has been used much more often in recent years.
A party of media and VIPs including Ipswich MP Ben Gummer and council leader David Ellesmere were shown the work so far and given a unique chance to stand in the dry several feet below water level.
Mr Gummer said: “It is really impressive, and will really make a difference to Ipswich. It is a substantial investment in the town’s security – £58m in total including £30m on the barrier itself.”
Mr Ellesmere said it was very important because the flood protection would reduce the danger for many properties and would allow more of the town centre to be developed with confidence.
The barrier will protect the town against surge tides similar to that which caused concern last month and back in October 2013.
It will take an hour to raise or lower the barrier because to do it any faster would risk it creating its own surge tide in a restricted area of the river.
Project manager Andrew Usborne said this was not normally a problem because there was always reasonable notice of potential surge tides giving plenty of time to close the barrier if necessary.
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