AECOM successfully delivered multidisciplinary flood protection services for a waterfront development in South West St Helier.
The objective of the project was to provide and design the necessary flood protection measures for a new mixed-use and park development. Collaborating closely with clients, master planning consultant, environmental impact assessment consultant, and key stakeholders such as the Infrastructure Housing and Environment Department of the Government of Jersey, we successfully delivered the project within the agreed timeframe and budget.
Option appraisal and concept design
Our team firstly conducted a desk-based review to assess the proposed alignment's suitability for flood protection. Working closely with key stakeholders, we facilitated an option appraisal process to identify the most suitable coastal protection structures. Through productive workshops and meetings, we achieved consensus on appropriate concepts, considering factors like overtopping and structural feasibility. Furthermore, we evaluated tie-in details between the new defences and existing coastal structures. Our approach incorporated considerations such as coastal process impacts, engineering constraints and opportunities, slipway requirements, impacts on a key heritage asset, potential wave focussing, and sea lettuce and beach amenity impacts.
Flood risk assessment and design
Leveraging our existing wave and flood models, we validated the agreed alignment and defence heights, which informed the concept design parameters for the new defences and slipway. Our team conducted joint probability analysis and overtopping assessments to enhance the flood model's accuracy. We utilised our ‘Tuflow’ inundation model to develop flood maps, enabling us to determine the required level of defences for different design events and significantly reduce the site's risk. Pending consent and further design, the proposed scheme will provide a robust 1:200-year Standard of protection at 2070, accounting for climate change.
Structural stability and geotechnical concept design
Within our project scope, we thoroughly assessed the structural stability and formulated geotechnical concept designs. Our experienced team ensured that the proposed coastal protection structures and new slipway complied with engineering standards and effectively addressed the relevant constraints. Through our expertise, we evaluated the stability of the structures and provided geotechnical recommendations to support the successful onward detailed design and implementation of the project.
Collaboration and expertise
Throughout the project lifecycle, we consistently demonstrated our expertise and fostered close collaboration with the Government of Jersey’s flood and coastal teams. This led to agreed and aligned outcomes with no points of difference with the Government’s coastal and flood team at the public enquiry, which we also attended, and provided evidence to the inspector, on behalf of the client.
Our thorough approach to option appraisal, concept design, flood risk assessment, and structural stability evaluation adhered to the agreed programme and budget. The project manager from the Jersey Development Company praised our team's “efficiency, knowledge, and professionalism”. With a perfect client satisfaction score, our services were highly recommended for their outstanding quality. This project exemplifies our commitment to providing comprehensive and effective solutions for coastal development projects, ensuring the protection and long-term sustainability of waterfront areas.