Langstone Coastal Defence Improvement Scheme

Havant Borough Council are undertaking a feasibility study to appraise options and develop outline designs for sea defences at Langstone to reduce coastal flood and erosion risk to 86 properties over the next 100 years, as well as critical infrastructure including the A3023, the only road access to Hayling Island.

In March 2018, the Eastern Solent Coastal Partnership (ESCP) on behalf of Havant Borough Council (HBC), secured £376,000 of funding made up from Regional Flood and Coastal Committee Levy and HBC Community Infrastructure Levy to progress the outline design stage of the Langstone scheme.

Where is the Langstone Frontage?

The Langstone scheme aims to develop a preferred coastal defence scheme for the Langstone frontage, near Havant, as recommended in the Portchester to Emsworth Flood and Coastal Erosion Risk Management (FCERM) Strategy (the Strategy - Environment Agency 2011).

The ~1km long Langstone frontage is located on the mainland immediately north of Hayling Island (see figure 1 below). Both Langstone and Chichester Harbours are sensitive sites, designated environmentally at a Local, National and International level.

The frontage is popular with locals and tourists due to its unique setting and is an important cultural heritage area, with 8 listed buildings in the Langstone Conservation Area and a historic Wadeway from Langstone to Hayling Island.

Why is there a need for a scheme?

The Strategy identifies that 56 residential and 3 non-residential properties are currently at significant risk of tidal flooding from a 0.5% AEP (1 in 200 year) event. In 100 years’ time, as a result of predicted sea level rise, this increases to 81 residential and 5 non-residential properties at risk from a 0.5% AEP event.

The A3023 road, classed as critical infrastructure, is at risk of tidal flooding and also erosion.  Securing the road and bridge from flooding and erosion is essential for emergency access on and off the island.

The existing defences consisting of a mixture of concrete walls, concrete block revetments and masonry quay walls which are in a poor condition. Currently maintained by HBC and other private owners, the majority of present defences have residual lives of less than 5 years (without any maintenance) and therefore, without a Langstone Scheme the existing community will continue to be at significant flood risk.

What is happening next?

The project team will be engaging with the local community and businesses in the upcoming months to understand their aspirations for this much needed scheme, followed by close engagement with key stakeholders throughout development of the scheme.

Ground and Structural Investigation Work

We will be undertaking ground and structural investigation (GI/SI) works around the Langstone seafront to determine the condition of existing defences. These works will involve undertaking a series of boreholes, trial pits and concrete cores to collect samples to determine the ground and existing defence structure conditions.

The data collected will help inform the options appraisal process.

Given the potential for archaeological finds, there will be an archaeological contractor onsite undertaking a watching brief alongside these GI/SI works.

How long will the works take?

The works are due to start on site the week commencing the 17th September 2018 and will last for approximately 2 weeks. During this time machinery, including a Cable Percussive Drilling Rig and a Dynamic Probing Rig will be used to determine ground conditions.

How will I be affected?

A small compound will be set up in the corner of the public car park adjacent to the Ship Inn, this will be fenced off for the duration of the works. Our contractors will fence off their work areas during the day and return it to public use at the end of each day.

There may be restricted access to the foreshore and temporary public footpath closures around the frontage. In the event of a footpath closure, diversions and signage will be put in place.

Please remain vigilant when using the footpath, particularly when machinery and materials is being delivered to site.

What will I see?

A compound will be set up in the corner of The Ship Inn carpark. A 4x4 vehicle transporting machinery from the compound around the site, including on the foreshore. The works will be kept separate from the public as far as possible.

 

Southmoor Scheme

The planning application for the Southmoor Managed Realignment Scheme was withdrawn recently by the Environment Agency (EA), due to a number of major constraints within the site relating to important utility infrastructure assets. The escalating requirements needed to protect these assets meant a decrease in the available land for potential habitat creation and a significant increase in scheme construction costs.  Even with contributions secured towards the costs of the scheme, the scheme is not financially viable and therefore will not be progressed any further by the EA. The ESCP will review the Southmoor scheme from a flood risk management perspective during the appraisal stage of the Langstone scheme. 

Click here to view the ESCP Southmoor position statement.

 

Figure 1 | Estimated Scheme extent location map

If you would like further information on the Langstone Coastal Defence Improvement Scheme, please email coastal.team@havant.gov.uk

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