Recent developments in loss of life modelling for flood defence and dambreak risk assessments

To date the work done in the UK to assess the loss of life as a result of flooding has been limited, with the “Risk To People” model being the most commonly used tool to assess flood fatalities. However, it is an empirical, generalised model that does not use detailed information on each individual receptor in its “broad scale” estimates of loss of life. For a more accurate assessment of loss of life an agent-based model is required. An agentbased model simulates the interactions of autonomous receptors with a view to assessing their effects on the system as a whole. It can model the simultaneous operations of multiple agents (in this case people and vehicles) with floodwater, in an attempt to re-create and predict the actions of complex phenomena such as those that occur in a flood emergency. A prototype, agent-based Life Safety Model (LSM) has been used to estimate the loss of life for two embayments in the Thames Estuary. The LSM models individual receptors (e.g. people and cars) and their dynamic interaction with the flood wave. This is done by integrating transport routing models with the results of two dimensional hydrodynamic modelling. The LSM estimates fatalities from: drowning; exhaustion; building collapse; and vehicles being swept away. The LSM offers a scientifically robust method of assessing the residual risk behind flood defences and for dam breaks in terms of injuries and lives lost. Importantly, it allows the comparison of different emergency management strategies that could assist in reducing the loss of life during future flood incidents. The model was validated against historical data from the 1953 Canvey Island flood