North Portsea Island Phase 4b Update April 2022
We are back!
For the coastal defence team the new construction year begins in April. This is due to regulations not allowing work on the foreshore from October to March to protect overwintering birds.
Respecting nature is a priority of the scheme and the team works closely with Natural England. Langstone Harbour is an extremely special natural area, and as part of the Solent it is one of the most important coastal zones in the UK - providing a nationally and internationally recognised and protected overwintering zone for waders, ducks and geese. To ensure our scheme does not cause any unnecessary disturbance to these and all other coastal birds in Langstone Harbour, all construction works stop over winter, starting again in the spring.
Piling up the progress
The first stage of construction includes preparing the base for the next stretch of flood defence wall, installing a so-called sheet pile wall. 5m long steel piles are driven into the ground to provide structural support from the sea for the new wall.
Prior to piling, an 8-tonne mini digger is used to dig a trench in the foreshore in preparation for concrete work for the base of the wall.
The sheet piles are then installed using a Movax piling rig mounted to an excavator (see image). The rig holds the pile in the right position whilst creating the vibration to drive the pile into the ground. Piling work is expected to happen throughout April.
To ensure further protection of the environment during construction, a silt curtain is used along the frontage to capture any silt from the construction activities. The curtain has a floating top which allows it to rise and drop with the tides and ensures that water quality is not affected.