This study was commissioned to evaluate the risk of coastal flooding across assets managed by a leading water utility. The nature of their assets meant that they were positioned close to the sea, and as such experienced inundation due to tidal processes, storm surges and wave impacts. The risk assesment was designed to identify those assets that are at greatest risk of flooding now and in the future, to identify when assets will graduate into a high-risk category, and prioritise further studies and assessments accordingly.
The assessment followed a risk-based approach, where the probability of coastal inundation and its impact was quantified. Inundation probability was estimated based on the liklihood of extreme coastal processes reaching each asset, including its relative protection due to coastal defences and their potential for defence failure. Consequence were considered from the perspective of the impacts to the water network in terms of Cost of Failure.
The study highlighted 268 assets potentially at risk of coastal flooding. When considering the overall Risk Factor, the assets deemed to be at greatest risk were not always closest to the sea, and included assets further landwards but offered a greater route criticality.