Risk Based Integrated Urban Flood Management of Drainage Assets

This document is aimed at summarising a new procedure for drainage system analysis which is based on the assessment of risk, rather than focusing on the performance of the network. This enables investment decision targeted more effectively to areas of greatest need

Management of urban flood risks-the development of a risk-based method

Serious flooding in the UK over recent years has increased the attention on urban flooding and highlighted the need to better understand and manage urban flood risk. Further to this, water companies are under increasing pressure to reduce the number of flooding incidents as a result of inadequate network capacity and asset failure. Recent reports have highlighted that flooding has to be managed in an integrated manner. As the responsibility for drainage assets is distributed between a number of organisations, there is not only a need to cooperate and collate data from a range of sources, but also to attribute flooding to the various assets and the responsible organisations. This paper describes the work being undertaken on the DTI SAM project that is developing a procedure and supporting tools to enable decision-makers to take into account the probability and consequences of flooding, and attributing the flooding proportionally to assets that generate that flooding. In particular this presentation focuses on the risk methodology for attributing the Expected Annual Damage (EAD) to every part of the system, to enable the engineer to address its performance limitations

An urban drainage flood risk procedure - a comprehensive approach

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