Maximising the Standard of Protection of a Rock Revetment in Lahinch for a Predefined Capital Budget

The design of a rock revetment in Lahinch, County Clare, adopted an alternative approach to setting scheme performance standards. This approach sought to offer the maximum performance standard possible for a predefined capital budget. Here multiple defence geometries, offering a range of standards of protection were designed using batch processing routines that allowed thousands of defence combinations to be analysed quickly and easily. These multiple design variants were costed through a comparative assessment to identify the best ‘value for money’ standard of protection that could be achieved by the scheme considering the predefined capital budget. It was found that for a marginal increase in cost (15%), the standard of protection offered by the scheme could be improved from 1 in 20-year standard of protection in 2115 to a 1 in 200-year standard of protection in 2115. The use of batch processing routines considerably sped up the design process allowing numerous iterations to be tested, costed and compared to provide the optimal defence geometry, achieving the highest possible standard of protection for Lahinch.