PPS 15 Planning and Flood Risk (Revised)·Page 78·E7
Active Resistance – Temporary Flood Mitigation Measures
Temporary and demountable flood defences require effective warning systems and community alert schemes but are generally not appropriate for new developments due to reliability concerns; they are more suitable for existing buildings in the floodplain.
Active resistance – involves the use of temporary flood mitigation measures and requires an effective flood warning system or a neighbourhood alert scheme to allow for a reasonable lead in time in order to have the mitigation in place. Stand alone temporary and demountable defences are not normally considered appropriate for new developments due to the likelihood of them not being in place on time, being damaged by flood debris or the potential for being breached or overtopped. The main advantage of these temporary arrangements is that they would normally be less expensive than the more permanent solutions and are more practical and suitable for buildings already within the floodplain.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/PPS 15 - Planning and Flood Risk (Revised).pdf