Flood risk assessment of temporary works for infrastructure projects

Infrastructure projects within floodplains have the potential to expose receptors to flooding risk. This risk can result from both the permanent and temporary works associated with the project. Best practice (Australian Rainfall and Runoff, 2016 and AIDR, 2017) indicates that a risk-based decision-making process be performed to manage risks generated by relatively short-term projects, such as temporary works. However, in practice, temporary works are often assessed to the same design standards as permanent works. Temporary works projects have a shorter expected service life compared to permanent infrastructure. Therefore, the flood risk assessment should be conducted considering this shorter service life. Despite the availability of relatively simple but effective statistical methods to adequately calculate the probability of flooding for use in risk assessments of temporary works, these have not been widely adopted within industry. This paper provides guidance on how to estimate an appropriate likelihood and design standard for use in a flood risk assessment of temporary works. The results show the equivalent exceedance probability between permanent and temporary works taking in to account the respective expected service lives.