This paper describes the work being undertaken on the Dti SAM project (a 3 year research project completed in 2009) that developed a procedure and supporting tools to enable a risk based approach for assessing the consequences and cost of flooding and to attribute these costs back to the drainage system to enable effective management of drainage assets. This procedure has the potential to radically change the current approach to drainage management which is focused on system performance standards, and does not directly consider flood consequences or take into account potential systems failure.
The methodology allows, for the first time, process-based quantified assessment of flood risks in urban areas based on a range of system states, which is an essential requirement for flood risk management. The methodology not only looks at the performance of the system as it is designed to operate using all possible loading conditions (rainfall, river level), but also considers the risks associated with all possible system states; taking into account the possible collapse and blockage in pipe systems, which are responsible for up to half of all flooding incidences. The methodology is designed to allow an integrated approach which allows consideration of other systems to be assessed together with drainage systems, such as river and coastal flooding.
The procedure will enable asset managers to prioritise their investment and make the most cost effective use of available funds.