Coastal defence options for Colwyn Bay

Supporting decision-making for Colwyn Bay western coastal defences as part of the wider Colwyn Bay Waterfront Development Project.

As part of the wider Colwyn Bay Waterfront Development Project, Conwy Borough Council commissioned ABPmer to recommend the most appropriate defence option for the western part of Colwyn Bay, North Wales.

To identify a sustainable coastal defence solution, we used SEASTATES, modelling, coastal processes assessment and analysis. We developed conceptual understanding of beach behaviour including sediment sources, transport pathways and sinks, profile response to storm events and the system controls, which govern beach evolution, was of primary importance. We also considered how the natural hydrodynamic processes are modified by the local morphology. Particular attention was paid to describing the local wave effects and their effects on sediment movement along the western Colwyn Bay frontage.

The SEASTATES hindcast database was invaluable in providing wave conditions over the last 20 years, allowing an understanding of the baseline morphological regime. Once the observed morphological regime was accurately reproduced by our sediment transport model (forced by SEASTATES), we were able to present detailed insights into the likely impact of various scheme options.