The UK’s critical infrastructure is at greater risk of deterioration and failure under a changing climate. To build resilience into the design of mitigation solutions, a thorough understanding of the historical role of site-specific processes, geomorphological and geological conditions and possible future climate scenarios is needed. This webinar will present a case study of an engineering scheme developed to protect a section of the A40 in Carmarthenshire from erosion by the River Towy. Due to rapid lateral erosion rates, it was estimated that with no intervention the A40 would be undercut within 10 to 15 years. Hence, a mitigation solution was proposed that would provide both protection from imminent risk of failure but also consider resilience to future risk under a changing climate.
To provide a resilient solution, an optioneering exercise was undertaken to identify the constraints, risks and uncertainties of a range of options. A phased process of acquiring, analysing and integrating site-specific information was undertaken to arrive at a design that would provide long-term resilience for the A40, through which the preferred solution of an anchored embedded sheet pile retaining wall was determined. This process included:
- a desk study of historical mapping, aerial imagery and LiDAR to appraise the changes in the river planform over time,
- consideration of the benefits and limitations of different approaches based on site constraints, river morphology and geological information, and
- integrating all the information gathered through a geomorphological assessment of the options considering the future impact of climate change.
The steps taken in this approach will be outlined and discussed, from risk assessment and optioneering to design and construction, and will highlight the necessary multi-disciplinary, risk-based decision-making process that is required to develop resilient solutions.
