Performance of sandbags for domestic flood defence

The final line of defence against flooding lies with the property itself. Deploying effective domestic flood defence systems can mitigate the devastating effects of flooding. Traditionally, householders have relied upon the use of sandbags. The Environment Agency's and local authorities’ emergency response is strongly dependent on the use of sandbags. Nonetheless, there is very little published about the performance of sandbags as a domestic flood defence. This paper presents the results of experimental research carried out to assess the performance of sandbags as a domestic flood defence. The performance criteria included water leakage, structural integrity, ease of use and environmental impact. It is concluded that sandbags have only modest performance as a domestic flood defence. The results showed that leakage from sandbags increased rapidly with increase of the outside water level. A simple analytical analysis suggests that a sandbagged doorway behaves in a manner akin to a sharp-crested triangular weir. However, the efficiency of sandbags was dependent on the number of rows and the duration of the flood.