Community Proposed Options

Offshore Breakwater and Flood Gates

In 2019, the project team carried out two months of targeted engagement with local residents, where we discussed the leading defence options with those who would be directly impacted.

During this engagement, an alternative option was put forward involving the creation of an offshore breakwater and flood gates on the eastern side of the village. The project team agreed to revisit the option and undertake further assessment to re-assess its viability in more detail.

The assessment concluded that due to significant technical, social, environmental and cost issues associated with progressing this option the project team were not able to progress this option any further.

Natural England have been consulted on the breakwater option and have formally assessed its impacts. In their letter to Coastal Partners they state ‘Natural England has reviewed the potential environmental impacts of an offshore breakwater option in Chichester Harbour, as requested. While the advice contained in this letter is based upon an outline design which may be subject to further revision, it is Natural England’s view that the construction, operation and maintenance of a breakwater structure in the harbour will result in a number of adverse effects upon designated sites. On this basis, Natural England would not support the option of an offshore breakwater and encourages Coastal Partners to continue pursuing alternative less damaging solutions.’ 

The Chichester Harbour Conservancy has also been formally consulted on the breakwater option. Their response to Coastal Partners states ‘The Conservancy therefore has no choice but to oppose the offshore breakwater option since it would not be in keeping with our founding legislation. Furthermore, due to the scale of the proposals, we would consider this to be a ‘major development’ within the Area of Outstanding Natural Beauty (AONB). Aside from the need for an Appropriate Assessment and compensatory habitat, before any development of this scale can be permitted in a protected area all other alternatives must be considered and dismissed. In this case, there is viable alternative and preferred option. Consequently, the offshore breakwater option would be highly unlikely to gain the consents needed for the scheme to be implemented. The Conservancy is fully supportive of the preferred option of Coastal Partners and we look forward to working together during the detailed design stage.’ 

In summary, a breakwater with tidal gates is a technically viable solution which could be constructed and would provide the required standard of protection from flooding to Langstone village from the east.

However, the appraisal summarised in the Technical Note highlights the significant issues associated with progressing this option. The project team will therefore not be able to progress this option any further for the following reasons:

Environmental

• The breakwater would have a significant detrimental impact on the intertidal habitats and statutory ecological designations in the area. It is considered very unlikely that the Imperative Reasons of Overriding Public Interest (IROPI) mechanism could be used to justify the option given that there is a technically viable alternative solution which has less of an environmental impact (i.e. the preferred option).
• There would be requirement for delivering compensatory saltmarsh / mudflat habitat elsewhere to mitigate for losses. The average cost for creating intertidal habitat is estimated to be approximately £500k per hectare of habitat produced.
• There would be more damage (relative to the preferred option) to Habitats of Principal Importance under S41 of the Natural Environment and Rural Communities (NERC) Act 2006 and to species listed under Schedule 5 of the Wildlife and Countryside Act 1981.
• The breakwater option would be contrary to the Local Plan policy, the National Planning Policy Framework (NPPF) and the duty to have regard to conserving biodiversity conferred by the Natural England and Rural Communities (NERC) Act 2006

Cost

• The cost of the breakwater is estimated to be considerably greater than the preferred option:

  - construction costs estimated to be in the region of £10-20 million.

  - maintenance costs estimated to be in the region of £5-10 million over a 50-year period.

  - operational costs of the tidal gates will also be incurred.

• There would be an estimated funding shortfall of between £12-25 million

Social

• The breakwater would detrimentally impact navigation in the area, including rendering the public right of way along the ‘Wadeway’ as unusable.
• There is a risk that the breakwater could lead to sedimentation in the area behind the structure, which would have impacts on water quality, existing habitats and recreational uses in the area.
• There would be significant visible impacts from Langstone village
• The breakwater would also have a significant detrimental impact on the landscape, impacting the AONB and Langstone Conservation area.

Technical

• There are health and safety concerns associated with members of the public accessing the breakwater structure, with the potential for injuries and fatalities.
• Access onto the breakwater for maintenance and operation is an issue, particularly on the north side of the structure where new infrastructure would be required to enable vehicle access.
• Additional trained resources would be required to operate, man when in operation and test the tidal gates.
• New defences on the west of Langstone village would still be required and erosion defences on the east of the village would need to be replaced.

Property level resilience

In the absence of a wider scheme, property level resilience could be utilised, where possible, to mitigate the impact to properties at risk of flooding. However, this does not address the other strategic objectives of the scheme such as erosion risk and the replacement of failing/failed assets, reducing flood risk to the A3023 the only road onto and off of Hayling Island and associated impacts.

The funding being investigated and bid for to deliver the project is from a wide variety of sources. The majority of them are likely to fund the scheme due to outcomes of reduced impact on the A3023. In the absence of a scheme which delivers these wider objectives it is unlikely that enough funding will be available just for property level resilience.

However, if all the funding required to deliver the proposed scheme is not secured the responsibility to protect properties will be that of the landowners, as is currently the case, who could investigate property level resilience with the support of Coastal Partners.