by Roger Falconer - Cardiff University
Paper 133: Xia, J., Falconer, R. A., Lin, B. and Tan, G. 2011. Modelling flash flood risk in urban areas. Proceedings of the Institution of Civil Engineers, Water Management. 164(6), 267-282.
Abstract
In urban areas the impacts of flash floods can be very high due to these regions being generally... more
Abstract
In urban areas the impacts of flash floods can be very high due to these regions being generally densely populated and containing vital infrastructure. Parts of the UK have been particularly prone to such serious urban flooding in recent years, such as the 2004 Boscastle flood. 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. Therefore, it is appropriate to estimate the potential flood risk to people and property for improved flood risk management. In the current study, an integrated numerical model for estimating the flood risk in urban areas is outlined herein, including the module for predicting the 2D hydrodynamic characteristics of urban floods, together with a new module for predicting the flood risk to people (including children and adults) and property (including vehicles and buildings). The hydrodynamic module of this model was then verified against laboratory experimental data and real flood tracks in urban areas. Finally, the integrated model was applied to predict the flood risk to people and property for the Boscastle floods, with different reoccurrence frequencies. The predicted results for different flood scenarios indicated that: (i) people would be swept away in the majority of the flooded area for a flood with P = 1% (a return period of 100 years) , while they would be in danger almost in all the flooded area for a high flood, with P = 0.25% (a return period of 400 years) or 0.1% (a return period of 1000 years); (ii) vehicles would be washed away from the parking area in the centre of a car park during a flood with P = 1%, while they would also be flushed on the main road and main street, and in the car park during a flood with P = 0.25 or 0.1% ; and (iii) there would be no damage to buildings during a flood with P = 1%, but severe damage to buildings would be likely to occur during high floods. Therefore, the developed integrated model can be used to predict the potential flood risk to people and property in urban areas, and these predictions can be used for improved flood risk management.
Download (.pdf) 