What is Detailed Design?
The options appraisal culminated in an outline design proposal for the most achievable solution, also known as the ‘leading options’. The detailed design phase progresses these leading options to a higher level of design detail, where we aim to refine the elements described below:
Design and Buildability
The Design Consultant will complete the structural, geometric and interface designs as well as prepare the necessary design drawings. As well as using their own experience, they will collaborate on the design with a Contractor, who has experience in the successful delivery of similar coastal schemes to ensure the design considers its buildability in its unique setting. These will be used to provide detail for the planning approval and consenting process, and also in Construction.
During our consultations we have received feedback regarding the inclusion of some existing structures (walls) in the design. Following this, the design consultant will be undertaking targeted structural investigation of the existing walls.
Structural investigations as part of this phase of the project will be undertaken in the following areas:
- The walls between the Ship and Langstone High Street.
- The quay wall in front of the Royal Oak and adjacent properties
- Private defences at Mill Lane and Harbourside.
These investigations are likely to be undertaken in a phased approach to limit risk and intrusion into private property. The scope and extent of each phase will be tailored and refined based on the results of the previous stage. These early investigations will identify the intrusive investigations where absolutely essential.
The results of the structural investigation will influence the development of the design and determine, whether efficiencies of using existing structures can be included in the final design.
Materials, Appearance and Finish
Further work will be undertaken at this stage of design to establish the necessary materials required for construction, and to develop visualisations of the final appearance and finish. We will seek wherever possible to work together with the community, through representative groups, and our stakeholders for the selection of the materials and finishes.
It is very important that the appropriate materials and finishes are chosen so that they are acceptable to the regulators and valued by the local community. There will be opportunities for feedback on the proposals and we welcome comments from residents and stakeholders.
Further Ground Investigation is required to support the detailed design and construction stages of the Scheme. This will build upon a review of available information and look to complete our understanding of ground conditions over the whole scheme alignment.
The work will involve undertaking visual inspections, collecting samples and undertaking in-situ testing.
The Ground Investigations as well as the Structural Investigations will be some of the very earliest work that is undertaken by our design consultant. The consultant will ensure that they have all the necessary permits and permission required and we will keep the community updated on the project progression.
Ecological Surveys and Studies
Coastal Partners are passionate about the environment. Undertaking coastal projects can provide opportunity to enhance the environmental biodiversity where appropriate. Ecological surveying will contribute towards our understanding of the habitats, landscape and heritage of the area. Coastal Partner’s Environmental Team will undertake several different surveys and studies as part of this stage.
The following will be undertaken:
- Breeding and Overwintering bird surveys
- Bat and Badger survey
- Reptile Survey
- Botanical Survey
- Habitat Suitability Index assessment for Great Crested Newt
- Tree survey and Arboricultural Impact Assessment
- Phase 2 Intertidal Survey
Environmental Impact Assessment
To support the detailed design, we will undertake research to build the evidence base for the Environment Impact Assessment (EIA). EIA is a tool used to identify the environmental, social and economic impacts of a project prior to decision-making for approval of the required licences and consents.
We have produced an EIA Screening and Scoping report setting out what we believe to be necessary for inclusion in the EIA, and this has been submitted to our regulators for their opinion.
We are anticipating that an EIA will be required and that the following assessments will need to be included as a minimum:
- Marine and Terrestrial Ecological Surveys and assessments
- Bird Surveys and assessment
- Habitat survey and assessment
- Heritage Statement
- Landscape and Visual Impact Assessment
Operation of active flood assets
The new flood defence scheme at Langstone introduces some active flood defence assets, such as flood gates or barriers. These are required to be closed when high water levels are anticipated.
Working in partnership with the community and HBC the design consultant will develop a robust operation procedure.
An important part of this procedure will be to collaborate with any Community Flood Plan and local flood resilience activities.
Detailed design will enable us to refine our cost estimation for building and operating the scheme. To ensure affordability, an independent Cost Consultant will work with Coastal Partners throughout the design stage. Affordability elements of the scheme will include:
- Increase cost certainty on the whole life costs of the Langstone FCERM Scheme
- Draw in partnership funding contributions to close a funding shortfall for delivery
- Refine the financial business case to be made to draw down funding administered by the Environment Agency
Partnership Funding Contributions
The construction of the scheme is dependent upon full funding being achieved.
Huge progress has been made in securing contributions, however the scheme still has a funding shortfall of approximately 10-15% of the whole life costs.
Coastal Partners will be working with the community and stakeholders to secure additional private partnership funding. Delivery of a FCERM scheme at Langstone will be dependent on the ability for it to be fully funded.
Please visit here for more information on funding and investment for the Scheme.
Approvals, Licencing and Consents
In preparation for construction, the following applications will be submitted for licences and consents:
|Approval, Licenses and Consents|
|Planning Permission and discharge planning consents|
|Listed building consents|
|Harbour Works Licenses|
|Land Drainage Act Notices|
|Flood Risk Action Plan (FRAP)|
To provide the project with a high level of success for these approvals we will continue to liaise and consult with our stakeholders and regulators throughout detailed design. The consenting process is estimated to require 8 to 12 months following the completion of the scheme’s detailed designs and will be undertaken throughout 2022.