A risk assessment of ponding using grated drainage system in urban areas of Western Sydney in Australia

Urban flooding is a major issue in Australia and causes significant property damages and loss of lives. On-site detention and retention methods are generally used to reduce the risk of flooding, which are however relatively expensive options. Temporary on-site ponding has the potential to significantly reduce the cost of flooding. However, risks are associated with this approach. This paper presents the outcome of an assessment of temporary ponding of drains in urban areas in Western Sydney, Australia. The risk assessment focussed on the hazards of the ACO grated drainage system in an urban area. This was achieved through a workshop in cooperation with industry partners, academics and other stakeholders. The outcome of the risk assessment includes design limits and a conceptual risk management plan for ponding of an ACO drainage system. These limits are based on maximum allowable ponding as per the Australian Standards. It is expected that these maximum values will result in a more accurate design and a medium risk level for a drainage system.