Modelling flash flood risk in urban areas

Abstract

In urban areas, the impacts of flash floods can be very severe as these regions are generally densely populated and contain vital infrastructure. Parts of the UK have been particularly prone to serious urban flooding in recent years, such as Boscastle in 2004. Due to climate change, the occurrence of urban flooding is predicted to increase in the future, which is likely to lead to increasing flood risk to people and property in urban areas. It is therefore appropriate to estimate potential flood risk to people and property for improved flood risk management. This paper outlines an integrated numerical model for estimating flood risk in urban areas. The model includes a module for predicting the two-dimensional hydrodynamic characteristics of urban floods and a new module for predicting the flood risk to people (both children and adults) and property (including vehicles and buildings). The hydrodynamic module of this model was verified against laboratory experimental data and real flood tracks in urban areas. The integrated model was also applied to predict the flood risk to people and property for the Boscastle 2004 floods, with different recurrence frequencies. The developed integrated model can be used to predict the potential flood risk to people and property in urban areas and such predictions can be used as a rough assessment in improving flood risk management.