North Portsea Island project update

Coastal Partners have announced the start of a new construction season on the North Portsea Island coastal defense project.

According to the update, 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.

“To ensure our scheme does not cause any unnecessary disturbance to the birds in Langstone Harbour, all construction works stop over winter, starting again in the spring,” the officials said.

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 will 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. The rig holds the pile in the right position whilst creating the vibration to drive the pile into the ground.

To ensure further protection of the environment during construction, the crews will use a silt curtain along the frontage to capture any silt from the construction activities.

The North Portsea Island Scheme covers 8.4km of Portsmouth’s coastline from Tipner through to Milton. It is designed to a 1 in 500 year (plus allowance for climate change to 2100) standard of protection against flooding.

When fully complete in 2024, the scheme will reduce the risk of flooding from the sea to over 4,200 homes, 500 businesses, and critical infrastructure including the Eastern Road over the next 100 years.

Photo: Coastal Partners