Semi-Probabilistic Safety Assessment of Pipelines near Leeves

Traditionally Dutch design codes require a minimum distance between a pipeline and the toe of the levee: the ‘safety zone’. The codes provide additional design and maintenance requirements for pipeline sections located within this ‘safety zone’. For existing pipelines, designed before the establishment of the codes, the sections located in the vicinity of the levee often do not pass the deterministic criteria of the flood risk assessment guidelines. Relocating the pipeline or the levee at those sections will dramatically impact on social and economic aspects and is therefore only recommended if absolutely necessary. Dutch flood risk assessment guideline and pipeline code do allow for a more advanced assessment of the safety of these sections. One of the options is a probabilistic assessment; however the code does not provide clear guidance on how to perform such an assessment. Royal HaskoningDHV has developed a semi-probabilistic design approach to assess the probability of levee failure due to pipeline rupture. The approach has been successfully applied to the levees along the River Meuse in the south of the Netherlands. The semi-probabilistic approach that has been developed compares the expected likelihood of a dike failure caused by a pipeline rupture with the allowable probability of failure. The method has been presented to both the Dutch Pipeline Design Community and the Water Board and has been positively received