Similar to the Thames Barrier (though much smaller), the 20 metre wide gate will be raised during periods of extreme high tides to hold back the North Sea and, with the help of the sheet piling, keep Ipswich dry.
When finished, the project will reduce the risk of flooding to 1,608 homes and 422 businesses and support key infrastructure such as the fire station and council buildings. Everything upstream of the barrier will be protected against a tidal surge like the one experienced in 1953 and, more recently, in 2013.
The scheme included building a special tunnel to house two 132 kV cables, which replaced cables installed in the 1950's. The cables were at a high risk of damage from vibration caused by the construction work.
The cables have been diverted through a tunnel running underneath the Wet Dock Lock. The 2.1m diameter tunnel is 42 metres long, with 22m deep shafts on the east and west side of the Wet Dock Lock, with 8.2 and 6m diameters respectively.
You can read more about the project and its progress on a dedicated Environment Agency blog.